U.S. patent application number 11/470087 was filed with the patent office on 2007-01-25 for magnetic tape cassettes, tape reels for use therewith, resinous leaf springs, and a process for producing them.
This patent application is currently assigned to FUJI PHOTO FILM CO., LTD.. Invention is credited to Kazuo HIRAGUCHI, Wataru IINO, Shozo ONMORI.
Application Number | 20070018024 11/470087 |
Document ID | / |
Family ID | 19065645 |
Filed Date | 2007-01-25 |
United States Patent
Application |
20070018024 |
Kind Code |
A1 |
HIRAGUCHI; Kazuo ; et
al. |
January 25, 2007 |
MAGNETIC TAPE CASSETTES, TAPE REELS FOR USE THEREWITH, RESINOUS
LEAF SPRINGS, AND A PROCESS FOR PRODUCING THEM
Abstract
A magnetic tape cassette includes a case that is formed by
joining an upper half and a lower half, one or more tape reels, a
window and a reel urging member having a tape reel contacting
portion which contacts an upper part of the tape reel(s), bent arms
connected to opposite sides of the tape reel contacting portion and
sliding end portions provided at distal ends of the bent arm. A
slide groove is provided in an inner surface of a perimeter of a
window opening in the upper half and a window member has
hold-and-retain portions which hold the sliding end portions in
cooperation with a bottom surface of the slide groove into which
the sliding end portions have been fitted. A tape reel suitable for
use with the magnetic tape cassette, a resinous leaf spring and its
production process are also provided. Tape reels housed in a
cassette case can be urged toward the lower half by a member whose
structure is simple and permits easy fitting and removal. Assorted
collection of constituent materials, particularly for assorted
collection of resin materials and selective collection of resin
materials as separate from metal materials are possible.
Inventors: |
HIRAGUCHI; Kazuo; (Kanagawa,
JP) ; IINO; Wataru; (Kanagawa, JP) ; ONMORI;
Shozo; (Kanagawa, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
FUJI PHOTO FILM CO., LTD.
210, Nakanuma, AMinami-sahigara-shi
Kanagawa
JP
|
Family ID: |
19065645 |
Appl. No.: |
11/470087 |
Filed: |
September 5, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10209257 |
Aug 1, 2002 |
7121493 |
|
|
11470087 |
Sep 5, 2006 |
|
|
|
Current U.S.
Class: |
242/345.2 ;
G9B/23.025; G9B/23.065; G9B/23.066; G9B/23.069 |
Current CPC
Class: |
G11B 23/08728 20130101;
G11B 23/113 20130101; G11B 23/08721 20130101; G11B 23/037 20130101;
G11B 23/08771 20130101; G11B 23/0875 20130101 |
Class at
Publication: |
242/345.2 |
International
Class: |
G11B 23/04 20060101
G11B023/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 1, 2001 |
JP |
2001233941 |
Claims
1. A magnetic tape cassette comprising: a case that is formed by
joining an upper half and a lower half; a tape reel or tape reels
around which magnetic tape is wound and which are housed in said
case; and a kinky leaf-like reel urging spring that urges said tape
reel or each of said tape reels toward said lower half, said reel
urging spring having an engagement hole at an end and an
engage-and-stop grooved portion at the other end, said engagement
hole coming into engagement with an engaging pin erected on an
inner surface of said upper half so as to fix said pin and said
engage-and-stop grooved portion being such that an engage-and-stop
pin erected on the inner surface of said upper half is fitted
loosely into the engage-and-stop grooved portion so that it has
free play along a length of the engage-and-stop grooved portion.
Description
[0001] This is a divisional of application Ser. No. 10/209,257
filed Aug. 1, 2002. The entire disclosure of the prior application,
application Ser. No. 10/209,257 is hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates to magnetic tape cassettes such as
digital video cassette (DVC), tape reels for use with them that can
be broken down into parts, resinous (plastic) leaf springs, and a
process for producing them.
[0003] More specifically, the invention relates to a magnetic tape
cassette that has magnetic tape housed in a case made by joining an
upper and a lower half in a face-to-face relationship and which can
be disposed of by assorting the constituent materials simply enough
to reduce the impact on the environment, thereby facilitating the
recycling of the used cassette.
[0004] In order to ensure that the magnetic tape cassette discarded
after use is broken down into various parts which are then assorted
by material and recycled as feedstock for a second production, the
invention also provides tape reels in a magnetic tape cassette
which are of such a structure that the lower flange can be easily
separated from the upper flange, the two flanges capable of being
securely joined together at high enough precision in assembly to
minimize wobbling of the upper flange.
[0005] The invention also relates to resinous (plastic) leaf
springs that can be molded while achieving proper adjustment of
spring load, as well as a process for producing such leaf
springs.
[0006] Recording media cartridges and cassettes conventionally used
as the recording media in external storages in computers and the
like are divided into two major classes, magnetic or
magneto-optical disk cartridges, etc. that use disks such as
magnetic disks or magneto-optical disks as the recording media, and
magnetic tape cartridges or cassettes, etc. that use magnetic tape
as the recording media (and which are hereunder collectively
referred to as "magnetic tape cassettes").
[0007] The magnetic or magneto-optical disk cartridges and the
magnetic tape cassettes are also used to record and store data from
computers and the like. In order to protect the stored valuable or
important information, design consideration is made such that
magnetic or magneto-optical disks will not be damaged or that
magnetic tape will not jam or receive damage or will not be pulled
accidentally out of the record/reproduce apparatus.
[0008] The magnetic tape cassettes of the second class are used as
record/reproduce media in consumer or professional sound or image
recording/reproducing apparatus (including various types of
recorders such as video tape recorder and video cameras) or as
large-capacity recording media to back up data in external storages
in computers and the like.
[0009] Such magnetic tape cassettes are available in two types, the
first type comprising magnetic tape stretched between a pair of
tape reels that are housed rotatably within a case (body case)
composed of an upper and a lower half (this is a so-called two-reel
type) and the second type comprising magnetic tape wound around a
single tape reel which is also housed rotatably in the case (this
is a so-called one-reel type). Known examples of such magnetic tape
cassettes include those whose structural and dimensional
specifications are described in JIS X6127, X6129, X6130, X6171 and
X6172, as well as in ECMA-288, etc.
[0010] On the pages that follow, a magnetic tape cassette of a
two-reel type is described specifically as an example of the
magnetic tape cassette. Intended typically for use as a digital
video cassette (DVC), it consists of a case that contains a pair of
tape reels around which magnetic tape is wound and which allow the
magnetic tape to run for information recording and
reproduction.
[0011] FIG. 53 is an exploded perspective view showing the
structure of the prior art two-reel type magnetic tape cassette. As
shown, the case of the magnetic tape cassette which is generally
indicated by 450 consists of an upper half 452 and a lower half 454
that each have a rectangular bottom plate and peripheral walls and
which are joined in a face-to-face relationship and secured by a
plurality of fasteners such as screws 455 (which are five in the
illustrated case).
[0012] In the interior of the case 450 which is composed of the
upper half 452 and the lower half 454, magnetic tape 458 which is
stretched between a pair of tape reels 456, one on the supply side
and the other on the take-up side, is rotatably housed. Various
other parts are also housed in the interior of the case 450. The
pair of tape reels 456 are positioned along a sidewall 454c of the
lower half 454 and their movement in a plane is regulated by, for
example, a plurality of ribs 454e erected on the bottom plate 454a
of the lower half 454. Each of the tape reels 456 consists of a
reel hub (take-up hub) 456b to which an upper flange 456c and a
lower flange 456d are both welded.
[0013] The bottom plate 454a of the lower half 454 has two
extensions 460 that extend from the right and left sides in a
forward direction (to the left in FIG. 53). The extensions 460 have
semi-cylindrical tape guides 464 that stand vertically on the
bottom plate 454a and by which the magnetic tape 458 stretched
between the tape reels 456 is allowed to thread through a
predetermined path to become exposed in an opening 462 at the front
face of the cassette case. The space between the extensions 460 is
not occupied by the lower half 454 but forms the opening 462 in the
cassette case.
[0014] The bottom plate 454a of the lower half 454 also has two
reel shaft insertion holes 454b. By means of the insertion holes
454b, a pair of tape reels 456 between which the magnetic tape 458
is stretched are supported rotatably and, in addition, when the
magnetic tape cassette is loaded on the record/reproduce apparatus,
reel shafts (not shown) on the record/reproduce apparatus pass
through insertion holes (not shown) in the lower side of the tape
reels 456 to engage them and thereby drive them to rotate.
[0015] The bottom plate 452a of the upper half 452 has openings so
that the amount in which the magnetic tape 458 has been wound
around the tape reels 456 can be seen (checked visually) from the
outside of the case 450. In the openings, transparent window
members (inspection windows) 452b made of transparent plastic
(resin) are mounted by a suitable method such as ultrasonic or
thermal welding.
[0016] A pair of reel retaining springs 466 in the form of a
metallic leaf-like reel urging spring are provided on the inner
surface of the upper half 452 (the lower surface in FIG. 53) in
positions that correspond to the respective tape reels 456. Each of
the reel retaining springs 466 is a leaf spring; its distal end
portion 466a is bent downwardly and its basal end portion 466b is
fastened to the lower surface of the bottom plate 452a of the upper
half 452 (its inner surface) by a suitable means such as screwing,
ultrasonic welding or thermal welding (neither is shown) so that
the distal end portion 466a is cantilevered and depresses the
center of the corresponding tape reel 456 to be urged toward the
lower half 454.
[0017] In order to ensure that dust will not get into the upper
half 452 when the magnetic tape cassette is not in service, the
front face of the upper half 452 (the left lateral face in FIG. 53)
is fitted with a front cover (lid) 467 which covers and protects
the magnetic tape 458 (its front and back sides) as it is stretched
between a pair of tape guides 464 on the lower half 454. The front
cover (lid) 467 consists of three members, an outer lid 468, an
upper lid 470 and an inner lid 472. The outer lid 468 has lock pins
(guide pins) 474 that project inwardly from both lateral plates
468a. Since the lock pins 474 fit into engage-and-stop grooves 452d
in two sidewalls 452c of the upper half 452, the whole of the front
cover 467 can rotate to open in a direction approaching the upper
surface of the upper half 452. On the other hand, torsion coil
springs 475 fitted on the lock pins 474 urge the lid 467 in such a
direction that it closes the opening 462 between the two extensions
460 of the bottom plate 454a of the lower half 454 of the magnetic
tape cassette.
[0018] Sidewall portions 454c of the lower half 454 are fitted with
rotatable lid locking members 476 that engage the lock pins 474 on
the outer lid 468 to keep it closed. The lid locking members 476
are urged to engage the lock pins 474 by means of lid locking
springs (not shown) which are similarly mounted on the lower half
454.
[0019] When the magnetic tape cassette is taken out of the
record/reproduce apparatus, the lid locking members 476 keep the
outer lid 468 closed so that the operator will not inadvertently
touch the magnetic tape 458. When the magnetic tape cassette is
reloaded into the record/reproduce apparatus, the engagement is
removed by release pins (not shown) that project from the
record/reproduce apparatus, whereupon the outer lid 468 can be
rotated to open.
[0020] The lower half 454 also has a tape reel locking member 478
mounted in the rear end portion (the right farther end in FIG. 53).
The tape reel locking member 478 has tape reel engage-and-stop arms
478a and a slidable body 478b. The slidable body 478b is slidably
held by a pair of guide ribs 454d erected on the bottom plate 454a
of the lower half 454 and it is urged forward by a compressive coil
spring 480; as a result, each of the tape reel engage-and-stop arms
478a that spread in a V-shape come into engagement at the distal
end with engaging teeth 456a formed on the circumference of the
lower flange of the corresponding tape reel 456, thereby preventing
it from rotating to ensure that the magnetic tape 458 will not
unwind accidentally to get slack.
[0021] The lower half 454 is also fitted with an anti-erasure plug
482 that prevents inadvertent erasure of the data recorded on the
magnetic tape 458. The anti-erasure plug 482 has a finger that
projects from a lateral surface (the farthest side in FIG. 53) to
become exposed to the outside through an opening in a peripheral
wall of the upper half 452. By external manipulation of the finger,
the anti-erasure plug 482 can be moved back and forth along a guide
rib erected on the bottom plate 454a of the lower half 454, thereby
closing or opening a detection hole in the bottom plate 454a of the
lower half 454. A machine such as the record/reproduce apparatus
reads the state of the detection hole and, depending on whether it
is open or closed, determines whether new data can be written to
the magnetic tape 458.
[0022] The upper half 452, the lower half 454, the front cover 467
(i.e., the outer lid 468, the upper lid 470 and the inner lid 472)
and other principal components of the magnetic tape cassette are
formed of the same resin (plastic) material by injection molding.
The tape reels 456 (each consisting of the reel hub 456b, the upper
flange 456c and the lower flange 456d), the tape reel locking
member 478 and other members are formed of a different plastic
material by injection molding. The magnetic tape cassette may of
course use other injection molded members as appropriate.
[0023] As already mentioned, the conventional magnetic tape
cassette uses the reel retaining springs 466 that keep the tape
reels 456 from rotating in order to ensure that the magnetic tape
458 will not get slack or otherwise deteriorate. The reel retaining
springs 466 are metallic reel urging springs.
[0024] As shown in FIG. 53, such metallic reel urging springs are
commonly a pair of reel retaining springs 466 that correspond to
the pair of reels 456. Of course, various other designs of reel
retaining spring have been used or proposed.
[0025] FIG. 54 shows another conventional method that is commonly
used to hold the pair of reels 456; as shown, the reels are
retained by means of a single reel retaining spring 486.
[0026] FIG. 54 is a perspective view showing the inside of the
upper half fitted with a reel retaining spring of a different
design than is shown in FIG. 53. The reel retaining spring 486 of
the design shown in FIG. 54 has two end portions 486a bent
downward, with the center portion 486b being fixed to the lower
surface of the bottom plate 452a of the upper half 452 by a
suitable method such as screwing, ultrasonic welding or thermal
welding; both end portions 486a of the reel retaining spring 486
depress the tape reels 456 at the center so that they are urged
toward the lower half 454 (see FIG. 53). The two end portions 486a
of the reel retaining spring 486 are each cantilevered by means of
the center portion 486b and this parallels with the reel retaining
springs 466 shown in FIG. 53.
[0027] JP 60-166879 U discloses a reel retaining spring which is a
mesa-shaped leaf spring and indicated by 488 in FIGS. 55A and 55B.
The leaf spring 488 is provided for each of tape reels 490 and it
has a center portion 488a and two end portions 488b and 488c; the
center portion 488a will contact a pivot (convex) 490b on the top
of the center reel hub 490a of each tape reel 490 and depresses and
urges it toward the lower half 492, and the two end portions 488b
and 488c are bent down toward opposite sides of the center portion
488a to fit into grooves 496 made in the inner surface of the upper
half 494. The end portion 488b has a larger width at the distal end
that fits into a corresponding wider portion 496a of the groove
496. In order to load the magnetic tape cassette into the
record/reproduce apparatus and drive the tape reels 490 to rotate,
the reel shafts (not shown) on the record/reproduce apparatus are
passed through the reel shaft insertion holes 492a in the lower
half 492 and inserted into the holes 490c formed in the lower sides
of the tape reels 490; due to the resulting engagement, the pivot
490b on each tape reel 490 depresses the center portion 488a of the
leaf spring 488, whereupon the two end portions 488b and 488c of
the leaf spring 488 that fit into the grooves 496 in the upper half
494 contact the end portions of the respective grooves 496 in their
longitudinal direction, deforming to urge the tape reels 490 toward
the lower half 492.
[0028] JP 52-53205 Y discloses a reel retaining spring unit which,
being indicated by 500 in FIGS. 56A and 56B, is an integral
assembly of a spring body 500a and a plurality of legs 500b that
extend radially from the spring body 500a (and which are three in
the illustrated case). The spring units 500 each have a slider 500c
at the distal end of the leg 500b and these sliders 500c are placed
within slots 504 in the upper half 502 such that projections 504a
in the slots 504 are brought into engagement with lugs 500d of the
sliders 500c of the spring units 500; each of the sliders 500c is
allowed to slide along the slot 504 until the spring body 500a of
the spring unit 500 contacts a metal ball 506b fitted at the center
of the reel hub 506a of each tape reel 506 and urges it toward the
lower half 508.
[0029] JP 3-242889 A discloses a reel retaining spring which, being
indicated by 512 in FIG. 57, consists of a plurality of radially
extending legs 512a (that are four in the illustrated case) and
which is mounted as an integral unit with the center of the upper
surface of each tape reel 510, namely, on the upper surface of the
reel hub 510a. According to the patent, the reel retaining spring
512 is made of metal or highly resilient plastic. While there is no
specific disclosure of how to render the reel retaining spring 512
integral with the tape reel 510, the patent shows by illustration
that the legs 512a of the reel retaining spring 512 can be secured
to the upper surface of the reel hub 510a of the tape reel 510 by
screwing or welding as in the prior art (see FIG. 57).
[0030] As mentioned above, the magnetic tape cassettes are made of
metal or various kinds of resin. With the recent growing concern
over environmental problems, increasing attention is drawn to the
possibility that the increase in various kinds of wastes including
those of metals, resins (plastics) and composite materials may
cause adverse effects on the environment. A design consideration
that is becoming important is reducing the impact on the
environment by producing less wastes or developing products which,
if discarded, will not cause air, water or soil pollution and hence
do not become any problem in environmental conservation. To this
end, it is necessary to design industrial products, in particular,
magnetic tape cassettes that can be recycled at an existing plant
system.
[0031] To meet this need, JP 11-273295 A discloses a design that
can be applied to magnetic tape cassettes in order to facilitate
assorted collection of metals and plastics. This is achieved by a
mesa-shaped metallic reel retaining spring which, being indicated
by 522 in FIGS. 58A, 58B and 58C, comprises a central depressing
portion 522a that depresses the central area of a tape reel 520,
support portions 522c at opposite ends that are detachably
supported on the upper half 524, and a slope 522b that bridges the
central depressing portion 522a and the support portion 522c at
either end. To mount the mesa-shaped reel retaining spring 522 on
the upper half 524, the support portions 522c at opposite ends of
the spring 522 are passed into insertion areas 528 formed in lugs
526a at four sites on the perimeter of a transparent window member
526 in the upper half 524. The insertion areas 528 may be
through-holes or may be closed at an end. The window member 526 has
a weld rib 526b formed inward of the lugs 526a and on the perimeter
of the side which faces the upper half 524; by melting the weld rib
526, the window member 526 can be welded to the upper half 524.
[0032] Because of this design, the tape cassette disclosed in JP
11-273295 A has the advantage that no special jig or cutting tools
need be used to dislodge the metallic reel retaining spring (reel
urging spring) from the upper half and collect it as metal
material.
[0033] The prior art products described above have their own
problems. First, the metallic or resinous reel retaining springs
illustrated in FIGS. 53, 54 and 57 which are used in prior art
magnetic tape cassettes are mounted on the inner surface of the
upper half by securing means such as crimping, welding and
screwing. Hence, when disassembling a conventional magnetic tape
cassette after use and separating the components according to
whether they are made of resin or metal or resinous parts are
separated by resin type with a view to collecting the components by
material, the reel retaining spring cannot be dislodged easily;
needless to say, it cannot be removed unless the cassette case is
disassembled and dislodging the reel retaining spring from the
inner surface of the upper half is a complex operation that
involves considerable labor and cost. This has been a factor that
precludes the effort to break down the magnetic tape cassette
according to material and collect and recycle the respective
components in assortment.
[0034] The reel urging, metallic leaf spring 488 illustrated in
FIGS. 55A and 55B is simply retained by the force of friction with
the groove 496 into which it has been fitted, so it can be easily
disengaged from the groove 496. On the other hand, the leaf spring
488 may potentially come out of engagement with the groove 496
during assembly. As another problem, the lateral surfaces of the
leaf spring 488 contact two walls of the groove 496 in the
direction of shorter side whereas the two end portions 488b and
488c contact the other two walls of the groove 496 in the direction
of longer side (see FIG. 55B) and this may potentially result in
chipping the wall portions of the groove 496.
[0035] The metallic spring unit 500 illustrated in FIGS. 56A and
56B is such that the slider 500c of the leg portion 500b is
constricted at the lug 500d to receive the projection 504a
extending from the slot 504 to come into engagement with the lug
500d. It is not very difficult to bring the two lugs out of
engagement but, on the other hand, assembling the metallic spring
unit 500 is a complicated work, causing various problems such as
the potential breaking of the resinous projection 504a and resin
chipping of the bottom of the slot 504 due to the sliding of the
slider 500c.
[0036] The metallic reel retaining spring 522 illustrated in FIGS.
58A, 58B and 58C can be easily dislodged from the upper half 524;
however, if each of the insertion areas 528 has a closed end, the
distal end of each support portion 522c of the reel retaining
spring 522 may potentially cause resin chipping of the insertion
areas 528 whereas if they are through-holes, difficulty is involved
in molding operations or there is the need to form each insertion
area 528 by securing two parts together and an extra step must be
performed to make the lugs 526a on the inner surface of the upper
half 524. What is more, the reel retaining spring 522 may be easy
to separate from the upper half 524 but, on the other hand, the
window member 526 which is welded to the upper half 524 cannot be
easily dislodged.
[0037] These problems are by no means limited to the metallic reel
retaining spring 522, they also occur in resinous reel retaining
springs.
[0038] Speaking of various prior art magnetic tape cassettes
including the above-described two-reel type which has a web of
magnetic tape stretched between a pair of tape reels that are
housed rotatably within a cassette case, if they are discarded
after use, they are simply disposed of as unburnable waste in the
current practice. However, as already mentioned, in order to save
resources or protect the environment, it is most desirable to break
down the discarded magnetic tape cassette into various parts,
assort them by material and recycle the respective materials as
feedstock for a second production.
[0039] In the conventional magnetic tape cassette, however, a pair
of tape reels between which a web of magnetic tape is stretched are
usually each composed of a lower flange integral with a reel hub
around which the magnetic tape is wound and an upper flange fixed
to the upper end of the reel hub, and the two flanges which are
made of different materials are fastened together by ultrasonic or
thermal welding. Once the upper and lower flanges are fastened
together by ultrasonic or thermal welding to make a tape reel,
considerable difficulty is involved in disassembling it safely and
assorting the individual components by material.
[0040] The precision in assembly of the upper flange relative to
the reference plane of the lower flange (which is usually its lower
surface) is desirably as small as possible in order to prevent
wobbling of the upper flange and keeping the magnetic tape wound in
neat form and, most desirably, the precision is about 0.01 mm and
less. However, the surface of the upper flange which is to be
welded to the lower flange and the reference plane of the lower
flange are not usually molded by a single die but molded by two
dies, one fixed and the other movable, and on account of various
factors including the precision in mating of dies, its thermal
deformation and the pressure of molten plastic being injected, the
mating position of dies is inevitably subject to change and it has
been difficult to secure adequate precision in assembly of the
upper flange. As a further problem, the upper flange is welded to
the lower flange in a position much inward of its circumference and
the wobbling of the upper flange will increase progressively from
the center outward; as an inevitable result, the practically
feasible precision in assembly of the upper flange has been about
0.1 mm-0.5 mm.
[0041] As already mentioned, the magnetic tape cassette is
disassembled into respective components which are assorted so that
they can be recycled as feedstock for a second production. In view
of this, the components to be assorted are desirably made of the
fewest kinds of materials and total elimination of metal from the
magnetic tape cassette has been proposed. Hence, it is desired that
the reel retaining spring which is conventionally made of metal and
used to prevent unwanted rotation of magnetic tape should also be
replaced by a plastic leaf spring. In addition, in order to ensure
that the leaf spring is not an impurity that gets into the
discarded upper half when it is recycled as feedstock for a second
production, the retaining spring is desirably made of the same
material as the upper half on which it is to be mounted.
[0042] However, the upper half which combines with the lower half
to make the cassette case must have sufficiently high rigidity and
strength that it can not only be loaded into or unloaded from the
record/reproduce apparatus but also withstand transport. If highly
rigid plastic is chosen to make the reel hub retaining spring of
the same material as the upper half, the spring load will change
considerably with the slightest change in thickness. Hence, in
order to determine the thickness of the spring that assures an
appropriate spring load for preventing unwanted rotation of
magnetic tape, a lot of samples must be prepared at different
thicknesses and it is necessary to check for the appropriate
thickness of spring; on top of this, variations in thickness must
be controlled but this adds to the complexity in manufacturing
procedures.
SUMMARY OF THE INVENTION
[0043] The present invention has been accomplished under these
circumstances and has as an object providing a magnetic tape
cassette that is free from the aforementioned problems of the prior
art and which meets the various requirements of recycling its
components at an existing plant system.
[0044] Another object of the invention is to provide a tape reel
that can be broken down and which is suitable for use with the
magnetic tape cassette.
[0045] Still another object of the invention is to provide a
resinous leaf spring.
[0046] Yet another object of the invention is to provide a process
for producing the resinous leaf spring.
[0047] Thus, one of the principal objects of the invention is to
provide a magnetic tape cassette that is free from the problems of
the prior art, that permits tape reels in a cassette case to be
urged by means of a member which is simple in structure and can be
easily fitted and removed, and that is advantageous for assorted
collection of constituent materials, particularly for assorted
collection of resin materials and selective collection of resin
materials as separate from metal materials.
[0048] Specifically, a first object of the invention is to provide
a magnetic tape cassette that permits tape reels in a cassette case
to be urged by means of a member which is simple in structure and
can be easily fitted and removed and that is advantageous for
assorted collection of constituent resin materials.
[0049] A second object of the invention is to provide a magnetic
tape cassette that permits a reel retaining spring to be easily
removed from a cassette case, that allows the spring to be easily
separated even if it is made of metal and which therefore is
advantageous for selective collection of resin materials as
separate from metal materials.
[0050] Another principal object of the invention is to provide a
tape reel that is free from the problems of the prior art and which
will not tear apart during service but which can be easily broken
down for collection.
[0051] Specifically, a third object of the invention is to provide
a tape reel that can be easily broken down when a magnetic tape
cassette discarded after use is disassembled into respective
components so they are assorted by material but which will not tear
apart accidentally during service of the magnetic tape
cassette.
[0052] A fourth object of the invention is to provide a tape reel
which can be easily broken down into a lower flange and an upper
flange in order that a magnetic tape cassette discarded after use
is disassembled into respective components so they are assorted by
material and recycled separately as feedstock for a second
production, thereby contributing to the saving of resources or
protection of the environment and which is so designed that the
upper flange will wobble by the smallest possible amount.
[0053] Still another principal object of the invention is to ensure
that when a magnetic tape cassette discarded after use is recycled
as feedstock for a second production, the respective components
into which the magnetic tape cassette has been broken down can be
assorted by material as easily as possible.
[0054] More specifically, a fifth object of the invention is to
provide a resinous (plastic) leaf spring which replaces the
conventional metallic, reel hub retaining spring used to prevent
unwanted rotation of magnetic tape and of which the spring load can
be easily adjusted to a desired value during molding, as well as a
process for producing the resinous leaf spring.
[0055] A sixth object of the invention is to provide a magnetic
tape cassette in which a tape reel in a cassette case can be urged
by means of a resin member of simple structure, thereby
facilitating selective collection of different materials.
[0056] A seventh object of the invention is to provide a magnetic
tape cassette in which a tape reel in a cassette case can be urged
by means of a resin member of simple structure without using a
metallic spring, thus proving advantageous for assorted collection
of resin materials.
[0057] An eighth object of the invention is to provide a magnetic
tape cassette which, even if it is so designed as to permit easy
mounting and dismounting of a reel retaining spring, can be
assembled no less efficiently than the magnetic tape cassette of
conventional design and which is not at all affected in its basic
performance by adopting that design.
[0058] A ninth object of the invention is to provide a magnetic
tape cassette with a reel retaining spring that is not only made of
resin (plastic material) but also so shaped as to allow for easy
assembling during manufacture and disassembling during
recycling.
[0059] With a view to attaining the various objects stated above,
the present inventors took various approaches in reducing the
wastes from magnetic tape cassettes having the aforementioned
various designs (i.e., reducing their impact on the environment)
and made intensive studies on a structure that would enable a reel
retaining spring to be easily taken out of the magnetic tape
cassette. As a result, the inventors found various designs for
cassette case that would be effective in assorting different
materials and which could simplify the procedure of breaking it
down, in particular, those designs which would allow the reel
retaining spring to be easily taken out of the cassette case. The
present invention has been accomplished on the basis of this
finding.
[0060] The present inventors thought that the magnetic tape
cassette of the invention should further satisfy the following
requirements: it should be assembled no less efficiently than
magnetic tape cassettes of conventional designs; the reel urging
spring used as a reel retaining spring should be easily mounted in
and dismounted from the magnetic tape cassette so that there will
be no drop in strength and shape stability (i.e., no torsion or
warpage should occur); most importantly, the alteration in the
design for mounting the reel urging spring should not cause any
adverse effects on the basic performance of the magnetic tape
cassette. The present invention has been accomplished on the basis
of these additional considerations.
[0061] In order to attain the first principle object, in particular
the first object described above, a first aspect of the present
invention provides a magnetic tape cassette comprising:
[0062] a case that is formed by joining an upper half and a lower
half;
[0063] a tape reel or tape reels around which magnetic tape is
wound and which are housed in the case;
[0064] a window through which the magnetic tape is visible and with
which the upper half is provided; and
[0065] a reel urging member having a tape reel contacting portion
which contacts an upper part of the tape reel or each of the tape
reels, bent arms connected to opposite sides of the tape reel
contacting portion and sliding end portions provided at distal ends
of the bent arms,
[0066] wherein a slide groove along which the sliding end portions
of the reel urging member slide is provided in an inner surface of
a perimeter of a window opening in the upper half and a window
member which is removably fitted in the window opening has
hold-and-retain portions which hold the sliding end portions in
cooperation with a bottom surface of the slide groove into which
the sliding end portions have been fitted.
[0067] In order to attain the above-mentioned first principle
object, in particular the second object described above, a second
aspect of the present invention provides a magnetic tape cassette
comprising:
[0068] a case that is formed by joining an upper half and a lower
half;
[0069] a tape reel or tape reels around which magnetic tape is
wound and which are housed in the case; and
[0070] a kinky leaf-like reel urging spring that urges the tape
reel or each of the tape reels toward the lower half, the reel
urging spring having an engagement hole at an end and an
engage-and-stop grooved portion at the other end, the engagement
hole coming into engagement with an engaging pin erected on an
inner surface of the upper half so as to fix the pin and the
engage-and-stop grooved portion being such that an engage-and-stop
pin erected on the inner surface of the upper half is fitted
loosely into the engage-and-stop grooved portion so that it has
free play along a length of the engage-and-stop grooved
portion.
[0071] In order to attain the second principle object, in
particular the third object described above, a third aspect of the
present invention provides a tape reel that can be broken down and
which has:
[0072] a lower flange having a reel hub around which magnetic tape
is wound;
[0073] engage-and-stop lugs provided on the reel hub of the lower
flange; and
[0074] an upper flange that fits to an upper end of the reel hub
and which has engage-and-stop pawls that are fixed by coming into
engagement with the engage-and-stop lugs.
[0075] The third aspect of the present invention also provides a
tape reel which further includes a reel urging spring having a
central base from which a plurality of elastic arms extend radially
to urge the tape reel, magnetic tape being wound around the tape
reel which is housed in a case formed by joining an upper half and
a lower half, the elastic arms of the reel urging spring coming
into slidable engagement with an engagement groove provided in
either the reel hub of the lower flange or the upper flange or in
both, and the central base contacting an inner surface of the upper
half so that the reel urging spring urges the tape reel toward the
lower half.
[0076] In order to attain the third object described above, a
fourth aspect of the present invention provides a tape reel that
can be broken down and which has:
[0077] a lower flange having a reel hub around which magnetic tape
is wound and also having a first engage-and-stop pawl;
[0078] an upper flange that fits to an upper end of the reel hub of
the lower flange and which has a second engage-and-stop pawl which,
when twisted, meshes with the first engage-and-stop pawl to become
fixed; and
[0079] an engage-and-stop member which not only fits to the lower
flange but also has a third engage-and-stop pawl which, when
twisted, engages the position where the first and second
engage-and-stop pawls on the lower flange and the upper flange are
in engagement with each other, thereby preventing undesired
twisting of the upper flange.
[0080] In order to attain the above-mentioned second principle
object, in particular the fourth object described above, a fifth
aspect of the present invention provides a tape reel that can be
broken down and which has a lower flange having a reel hub around
which magnetic tape is wound and an upper flange mounted on an
upper end of the reel hub of the lower flange, the tape reel
having:
[0081] engage-and-stop lugs provided on the lower flange;
[0082] engage-and-stop members that are provided on the upper
flange and which come into contact and engagement with the
engage-and-stop lugs so as to join the lower flange with the upper
flange;
[0083] an area of contact between the lower flange and the upper
flange which is situated inward of the engage-and-stop members on
the upper flange but in a position away from a flange surface of
the upper flange; and
[0084] an urging means that applies urging force between an area of
contact and the engage-and-stop members on the upper flange that
have come into contact and engagement with the engage-and-stop lugs
on the lower flange, thereby causing the engage-and-stop members to
be elastically secured to the engage-and-stop lugs,
[0085] wherein the lower flange is molded by a pair of dies
including a fixed die and a movable die, with a reference plane of
the lower flange and the engage-and-stop lugs as molded being
provided by parallel die surfaces oriented in a same direction that
have been formed on either the fixed die or the movable die.
[0086] In a preferred embodiment of the fifth aspect, said area of
contact is provided by an elastic convex formed in the center of
said reel hub of said lower flange or in the center of said upper
flange, with said upper flange being fixed in a predetermined
position by the urging force of said elastic convex. In another
preferred embodiment, said area of contact is provided by a convex
formed in the center of said reel hub of said lower flange or in
the center of said upper flange, with the upper flange being fixed
in a predetermined position by the urging force created when said
upper flange deforms elastically.
[0087] In yet another preferred embodiment, said area of contact is
provided by an elastic convex formed in the center of said reel hub
of said lower flange or in the center of said upper flange, with
said upper flange being fixed in a predetermined position by the
interaction between the urging force of said elastic convex and the
urging force created when said upper flange deforms elastically.
More preferably, said engage-and-stop members are engage-and-stop
pawls that come into engagement with said engage-and-stop lugs by
snap fit.
[0088] In order to attain the third principle object, in particular
the fifth object described above, a sixth aspect of the present
invention provides a resinous leaf spring which has thin-walled
portions or recesses or cutouts formed in selected areas and the
spring load of which is adjusted by changing either a thickness of
the thin-walled portion or a size or depth of the recesses or the
cutouts or their position during molding of the leaf spring.
[0089] The present invention also provides a process for producing
a leaf spring with a die assembly, the die assembly having a base
part which defines a basic shape of the leaf spring and a moving
part that is capable of movement relative to the base part, either
the base part or the moving part being equipped with a movable part
that allows adjustment of a spring load of the leaf spring and
which is adjusted in position to provide a specified spring
load.
[0090] Said movable part that allows adjustment of the spring load
is desirably one that adjusts said spring load by changing the
thickness of said leaf spring or one that adjusts said spring load
by changing the sizes, depths or positions of recesses or cutouts
formed in selected areas of said leaf spring.
[0091] In order to attain the above-mentioned third principle
object, in particular the sixth object described above, a seventh
aspect of the present invention provides a magnetic tape cassette
comprising:
[0092] a case that is formed by joining an upper half and a lower
half;
[0093] a tape reel or tape reels around which magnetic tape is
wound and which are housed in the case; and
[0094] a reel urging member which urges the tape reel or each of
the tape reels toward the lower half, which is generally of a V
shape in cross section and which has a base portion secured to an
inner surface of the upper half and a tape reel contacting portion
in a form of an inclined plane that is connected to an end of the
base portion via a bend.
[0095] In order to attain the above-mentioned third principle
object, in particular the seventh object described above, an eighth
aspect of the present invention provides a magnetic tape cassette
comprising:
[0096] a case that is formed by joining an upper half and a lower
half;
[0097] a tape reel or tape reels around which magnetic tape is
wound and which are housed in the case; and
[0098] a reel urging member which urges the tape reel or each of
tape reels toward the lower half and that deforms elastically in a
direction generally perpendicular to a direction in which the tape
reel or each of the tape reels are urged.
[0099] Preferably, said reel urging member comprises a pair of
flexible ribs erected on the inner surface of said upper half to
extend toward said lower half and a contact member that is fitted
over the distal ends of said flexible ribs and which have an
inclined inner surface describing a generally U shaped cross
section.
[0100] In another preferred embodiment, said reel urging member
comprises a pair of flexible ribs erected on the inner surface of
said upper half to extend toward said lower half and a recess in
the form of an inverted cone that is made in the upper surface of
the tape reel and into which the distal ends of said flexible ribs
are inserted.
[0101] In order to attain the above-mentioned third principle
object, in particular the eighth object described above, a ninth
aspect of the present invention provides a magnetic tape cassette
having a recording medium housed between an upper half and a lower
half joined to each other in a face-to-face relationship, wherein a
reel urging spring an insertion portion of which has at least two
bends is inserted into a reel urging spring insertion area provided
in the upper half and a cover portion of the reel urging spring
insertion area is an easy-to-break part.
[0102] In a preferred embodiment of the ninth aspect, said
easy-to-break part is surrounded by a groove formed in a selected
region of the cover portion of said reel urging spring insertion
area in such a way that said cover portion can be easily broken.
The groove may be provided in the upper surface (obverse surface)
of said upper half or it may be provided in its lower surface. The
depth of the groove may be determined as appropriate.
[0103] In another preferred embodiment of the ninth aspect, said
reel urging spring insertion area provided in said upper half may
be formed by conventional molding technology without using a slide
core. The at least two bends formed on said reel urging spring
preferably exhibit a specified degree of spring elasticity when the
reel urging spring is inserted into said reel urging spring
insertion area.
[0104] In order to attain the above-mentioned third principle
object, in particular the ninth object described above, a tenth
aspect of the present invention provides a magnetic tape cassette
comprising:
[0105] a case that is formed by joining an upper half and a lower
half in a face-to-face relationship and in which magnetic tape is
housed;
[0106] a tape reel or tape reels for winding up the magnetic
tape;
[0107] a reel urging spring having a central base from which a
plurality of elastic arms extend radially to urge the tape reel or
each of the tape reels; and
[0108] spring seats that are provided in the central base portion
of an upper flange of the tape reel or each of the tape reels and
which hold in position the reel urging spring by placing distal
ends of the elastic arms to rest on the spring seats or by fitting
them into the spring seats,
[0109] wherein the central base portion of the reel urging spring
contacts an inner surface of the upper half and urging force
developed by the reel urging spring as a result of deformation of
the elastic arms urges the tape reel or each of the tape reels
toward the lower half.
[0110] Preferably, said spring seats are provided in a recess
formed in the center of the upper flange of said tape reel and the
distal ends of the elastic arms of said reel urging spring lie in
the same plane as the central base of said reel urging spring.
[0111] It is also preferred that the central base of said reel
urging spring is formed at a higher position than the distal ends
of said elastic arms.
[0112] In another preferred embodiment, a downwardly projecting
pivot is formed on said upper half in the position corresponding to
the center of said tape reel and a recess into which the pivot is
fitted is provided in the central base of said reel urging
spring.
[0113] In yet another preferred embodiment, an upwardly projecting
pivot may be formed in the central base of said reel urging spring
and a recess into which the pivot is fitted is provided in the
inner surface of the upper half.
[0114] The pivot provided to project either from said upper half or
from the central base of the reel urging spring is preferably made
of plastic having low enough friction coefficient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0115] FIG. 1 is a perspective view showing how the inner surface
of an upper half of an example of the magnetic tape cassette
according to the first aspect of the invention looks like;
[0116] FIG. 2A is a perspective view showing the structure of an
upper half of another example of the magnetic tape cassette
according to the first aspect of the invention;
[0117] FIG. 2B is a partial enlarged view of FIG. 2A;
[0118] FIG. 3 is a perspective view of a window member to be fitted
on the upper half shown in FIGS. 2A and 2B;
[0119] FIG. 4 is a perspective view of a reel urging member to be
fitted on the upper half shown in FIGS. 2A and 2B;
[0120] FIG. 5 is a perspective view showing the inner surface of an
upper half of yet another example of the magnetic tape cassette
according to the first aspect of the invention;
[0121] FIG. 6A is a plant view showing the inner surface of an
upper half of an example of the magnetic tape cassette according to
the second aspect of the invention, as well as the structure of a
leaf-like reel urging spring used in the upper half;
[0122] FIG. 6B is section A-A of FIG. 6A;
[0123] FIG. 7A is a perspective view showing the structure of an
example of the reel urging spring in the magnetic tape cassette
according to the second aspect of the invention;
[0124] FIG. 7B is a perspective view showing another example of the
reel urging spring;
[0125] FIG. 8 is a schematic cross-sectional view showing the
structure of an upper half in another example of the magnetic tape
cassette according to the second aspect of the invention;
[0126] FIG. 9A is a schematic cross-sectional view illustrating how
the reel urging spring is retained temporarily in the upper half
shown in FIG. 8;
[0127] FIG. 9B is a schematic cross-sectional view illustrating how
the reel urging spring is mounted on the upper half,
[0128] FIG. 10 is a perspective view showing a reel urging member
as it has been fitted on the upper half of a magnetic tape cassette
according to an example of the seventh aspect of the invention;
[0129] FIG. 11 is a schematic cross-sectional view illustrating how
a tape reel is urged by means of the reel urging member shown in
FIG. 10;
[0130] FIG. 12 shows in conceptual form a reel urging member
according to another example of the seventh aspect of the
invention;
[0131] FIG. 13A is a schematic cross-sectional view illustrating
the structure of a reel urging member of an example of the magnetic
tape cassette according to the eighth aspect of the invention;
[0132] FIG. 13B is a schematic cross-sectional view illustrating
how a tape reel is urged by means of the reel urging member;
[0133] FIG. 14 is a plan view showing the inner surface of an upper
half in an example of the magnetic tape cassette according to the
eighth aspect of the invention,
[0134] FIG. 15A is a schematic cross-sectional view illustrating
the structures of a reel urging member and a tape reel in another
example of the magnetic tape cassette according to the eighth
aspect of the invention;
[0135] FIG. 15B is a schematic cross-sectional view illustrating
how a tape reel is urged by means of the reel urging member;
[0136] FIG. 16A is a perspective view showing the whole external
appearance of a magnetic tape cassette according to an example of
the ninth aspect of the invention;
[0137] FIG. 16B is a partial enlarged view of FIG. 16A;
[0138] FIG. 17 shows in section an area of the magnetic tape
cassette according to the example shown in FIGS. 16A and 16B where
a reel urging spring is inserted;
[0139] FIG. 18 shows how the reel urging member shown in FIG. 17
looks like in the free state;
[0140] FIG. 19 shows in section an area of the magnetic tape
cassette according to another example of the ninth aspect of the
invention where a reel urging spring is inserted;
[0141] FIG. 20 shows in section an area of the magnetic tape
cassette according to yet another example of the ninth aspect of
the invention where a reel urging spring is inserted;
[0142] FIG. 21 is a perspective view showing an example of the reel
urging structure in the magnetic tape cassette according to the
tenth aspect of the invention as it has been mounted in a tape
reel;
[0143] FIG. 22 is a perspective view showing enlarged the reel
urging structure of FIG. 21 as it has been mounted in the tape
reel;
[0144] FIG. 23 is a perspective view showing spring seats as
elements of the reel urging structure shown in FIG. 22;
[0145] FIG. 24 is a perspective view showing the upper surface of a
reel urging spring as another element of the reel urging structure
shown in FIG. 22;
[0146] FIG. 25 is a perspective view showing the lower surface of
the reel urging spring shown in FIG. 24;
[0147] FIG. 26 is a perspective view showing how the recess in the
reel urging spring shown in FIG. 24 is associated with a pivot
provided on the upper half;
[0148] FIG. 27 is a perspective view showing another example of the
reel urging structure in the magnetic tape cassette according to
the tenth aspect of the invention as it has been mounted in a tape
reel;
[0149] FIG. 28 is a perspective view showing in partial section
still another example of the reel urging structure in the magnetic
tape cassette according to the tenth aspect of the invention as it
has been mounted in a tape reel;
[0150] FIG. 29 is a perspective view showing the reel urging spring
mounting portion of the reel urging structure shown in FIG. 28,
except that the upper flange of the tape reel has been removed;
[0151] FIG. 30 is a perspective view showing the shape of the reel
urging spring shown in FIG. 28;
[0152] FIG. 31 is a perspective view showing in partial section the
overall shape of an example of a tape reel that can be broken down
according to the third aspect of the invention;
[0153] FIG. 32 is a perspective view showing an example of the
lower flange as a component of the tape reel shown in FIG. 31;
[0154] FIG. 33 is a perspective view showing an example of the
upper flange as another component of the tape reel shown in FIG.
31;
[0155] FIG. 34 is a perspective view showing an example of the reel
urging spring as still another component of the tape reel shown in
FIG. 31;
[0156] FIG. 35 is a perspective view showing in partial section the
overall shape of an example of a tape reel that can be broken down
according to the fourth aspect of the invention;
[0157] FIG. 36 is a perspective view showing an example of the
lower flange as a component of the tape reel shown in FIG. 35;
[0158] FIG. 37 is a perspective view showing an example of the
upper flange as another component of the tape reel shown in FIG.
35;
[0159] FIG. 38 is a perspective view showing an example of the
engage-and-stop member as still another component of the tape reel
shown in FIG. 35;
[0160] FIG. 39 is a perspective view showing in partial section the
essential part of the lower flange as a component of the tape reel
shown in FIG. 35;
[0161] FIG. 40 is a perspective view showing in partial section the
essential part of the upper flange as another component of the tape
reel shown in FIG. 35;
[0162] FIG. 41 is a perspective view showing in partial section the
essential part of the engage-and-stop member as still another
component of the tape reel shown in FIG. 35;
[0163] FIG. 42 is a fragmentary perspective view showing the
essential part in which the lower flange, the upper flange and the
engage-and-stop member have been combined in an example of the
fourth aspect of the invention;
[0164] FIG. 43 is a cross-sectional view showing the essential part
(central part) of a specific example of the tape reel that can be
broken down according to the fifth aspect of the invention;
[0165] FIG. 44 is a cross-sectional view showing the structure of
the essential part (central part) of a die assembly for molding the
reel hub of the lower flange in the same example of the fifth
aspect of the invention;
[0166] FIG. 45 is a cross-sectional view showing the essential part
(central part) of another example of the fifth aspect of the
invention;
[0167] FIG. 46 is a perspective view showing the shape of a reel
urging spring in the form of a resinous leaf spring according to an
example of the sixth aspect of the invention;
[0168] FIG. 47 is a cross-sectional view showing an exemplary die
assembly that may be used to mold the reel urging spring shown in
FIG. 46;
[0169] FIG. 48 is a perspective view showing the shape of a reel
urging spring in the form of a resinous leaf spring according to
another example of the sixth aspect of the invention;
[0170] FIG. 49 is a cross-sectional view showing an exemplary die
assembly that may be used to mold the reel urging spring shown in
FIG. 48;
[0171] FIG. 50 is a cross-sectional view showing the shape of a
resinous leaf spring (shape 1) according to still another example
of the sixth aspect of the invention;
[0172] FIG. 51 is a perspective view showing the shape of a
resinous leaf spring (shape 2) according to yet another example of
the sixth aspect of the invention;
[0173] FIG. 52 is a perspective view showing the shape of a
resinous leaf spring (shape 3) according to a further example of
the sixth aspect of the invention;
[0174] FIG. 53 is an exploded perspective view showing the
principal components of a conventional magnetic tape cassette;
[0175] FIG. 54 is a perspective view showing how the inner surface
of the upper half of a magnetic tape cassette looks like if it is
fitted with a different example of the conventional reel retaining
spring than is shown in FIG. 53;
[0176] FIG. 55A is a partial perspective view showing how the inner
surface of the upper half of a magnetic tape cassette looks like if
it is fitted with another example of the conventional reel
retaining spring;
[0177] FIG. 55B is a partial cross section of the magnetic tape
cassette as it has been fitted with the reel retaining spring shown
in FIG. 55A;
[0178] FIG. 56A is a perspective view of yet another example of the
conventional reel retaining spring;
[0179] FIG. 56B is a partial cross section of the magnetic tape
cassette as it has been fitted with the reel retaining spring shown
in FIG. 56A;
[0180] FIG. 57 is a perspective view of a tape reel in a magnetic
tape cassette as it has been fitted with still another example of
the conventional reel retaining spring;
[0181] FIG. 58A is a partial cross section of a magnetic tape
cassette as it has been fitted with a further example of the
conventional reel retaining spring;
[0182] FIG. 58B is a plan view of a window member as it has been
fitted with the reel retaining spring shown in FIG. 58A; and
[0183] FIG. 58C is a partial perspective view showing how one of
the lugs on the window member shown in FIG. 58B looks like if it is
seen from the inside.
DETAILED DESCRIPTION OF THE INVENTION
[0184] The magnetic tape cassettes of the invention, the tape reels
for use with them, as well as the resinous leaf spring and the
process for producing it are described below in detail with
reference to the preferred embodiments shown in FIGS. 1-52 in the
accompanying drawings.
[0185] On the pages that follow, the magnetic tape cassette of the
invention (which is hereunder sometimes referred to simply as the
cassette) will be described in detail. In the following
description, the term "upper" refers to the side on which the upper
half is located, the term "lower" refers to the side on which the
lower half is located, the term "front" refers to the side on which
the front cover is located, and the term "rear" refers to the
opposite side.
[0186] The concept of the invention is applicable to magnetic tape
cassettes having magnetic tape and a case in which the magnetic
tape is housed rotatably. It is applicable to magnetic tape
cassettes of either a one-reel type or a two-reel type, in which
magnetic tape is wound around a single tape reel or stretched
between a pair of tape reels, said tape reel or tape reels being
housed in the case at a specified area or specified areas such that
the magnetic tape can be pulled out of the case or allowed to run
in either a forward or reverse direction.
[0187] According to the invention, the case of the cassette (or
cassette case) refers to a component that has the upper and lower
halves as the principal components and include other members that
are to be fitted on the upper or lower half, as well as those
members which are fitted on the upper or lower half in order to
retain or house the tape reel or tape reels around which the
magnetic tape are wound and part of the magnetic tape that has been
drawn from the tape reels. Speaking of the magnetic tape cassette
of a two-reel type which is illustrated in FIG. 53, the other
members are those which are formed by combining the upper and lower
halves as they are composed of a plurality of members including the
front cover (i.e., the outer lid, upper lid and inner lid) that is
fitted on the upper half.
[0188] To start, we describe the magnetic tape cassette according
to the first aspect of the invention with reference to FIGS.
1-5.
[0189] In the magnetic tape cassette according to the first aspect
of the invention, the tape reels housed in the case are urged
toward the lower half by means of a reel urging member. Depending
upon the tape reels housed in the case, one or more reel urging
members are provided on the inner surfaces of the perimeters of the
windows in the upper half. For example, the magnetic tape cassette
shown in FIG. 53 has two or more reel urging members instead of the
leaf-like reel urging springs.
[0190] In the magnetic tape cassette according to the first aspect
of the invention, the reel urging member has a tape reel contacting
portion which contacts the upper part of the tape reel housed in
the case and two bent arms formed on opposite sides of the tape
reel contacting portion, with a sliding end portion being provided
at the distal end of either bent arm.
[0191] The tape reel contacting portion is a site that contacts the
upper part of the tape reel housed in the case which is formed by
combining the upper and lower halves; it may be flat, or generally
of an inverted V shape or in any other shapes including one that
contacts the upper part of the tape reel at one or more sites.
[0192] Both sides of the tape reel contacting portion are bent as
arms and at the distal end of each bent arm, there is provided a
sliding end portion that is to be inserted into a slide groove made
in the inner surface of the perimeter of the opening in the upper
half.
[0193] In order to ensure that the magnetic tape in the case can be
visually checked from the outside, a removable transparent window
member is fitted in the opening which forms an inspection window in
the upper half. In order that the tape reel around which the
magnetic tape is wound and which is housed in the cassette case is
urged toward the lower half, the sliding end portions of the reel
urging member are inserted into and slid along the slide groove
which is made in the inner surface of the perimeter of the
opening.
[0194] The slide groove traverses the center of the tape reel
housed in the case and it is made in the inner surface of the
perimeter of the opening to extend toward the front and rear sides
of the upper half such that the tape reel contacting portion of the
reel urging member whose sliding end portions are to be inserted
into the slide groove will contact the center of the reel hub in
the tape reel. The sliding end portions of the reel urging member
are inserted into the slide groove and, after being located in the
front and rear slide grooves which are on opposite sides of the
center in the longitudinal direction of the slide groove, the
sliding end portions slide on the inner bottom surfaces of the
front and rear slide grooves.
[0195] The transparent window member which is to be removably
fitted in the window opening has hold-and-retain portions that are
to be placed on the lower surfaces of the front and rear slide
grooves along which the sliding end portions of the reel urging
member as inserted into the slide groove will slide and which hold
the sliding end portions in cooperation with the inner bottom
surfaces of the front and rear slide grooves. The distal ends of
the hold-and-retain portions are fitted in a stepped area formed
along the slide groove in the inner surface of the upper half.
[0196] In the first aspect of the invention, the slide groove along
which the sliding end portions of the reel urging member slides in
order to retain the reel urging member on the inner surface of the
upper half is made in the inner surface of the upper half and the
distal end of each of the hold-and-retain portions of the window
member which hold the sliding end portions in cooperation with the
slide groove is fitted into the stepped area formed along the slide
groove in the inner surface of the upper half; hence, there is no
need to provide extra projections on the inner surface of the upper
half.
[0197] When the tape reel in the cassette according to the first
aspect of the invention depresses the tape reel contacting portion
of the reel urging member toward the upper half as it contacts the
tape reel, for example, in the case where the magnetic tape
cassette is loaded in the record/reproduce apparatus and the tape
drive unit is fitted in the lower part of the tape reel so that the
latter is depressed toward the upper half, the tape reel contacting
portion is depressed toward the upper half and the sliding end
portions of the bent arms slide on the inner bottom surface of the
slide groove toward its front and rear ends as the bent arms deform
to spread, whereupon the tape reel is urged toward the lower
half.
[0198] The sliding end portions of the reel urging member which are
to be held by the hold-and-retain portions of the window member in
cooperation with the inner bottom surfaces of the slide groove
(i.e., the front and rear slide grooves) are free ends and, in the
absence of any part that constrains (contacts) the distal end of
either sliding end portion of the reel urging member while they
slide, the sliding end portions are free to slide and this
contributes to eliminating or reducing problems such as resin
chipping.
[0199] To assemble the cassette according to the first aspect of
the invention, the following procedure may be taken. The window
member is fitted in the window opening in the upper half and the
distal ends of the hold-and-retain portions of the window member
are fitted in the stepped area formed along the slide groove on its
perimeter; then, each of the sliding end portions of the reel
urging member is inserted between the inner bottom surface of the
slide groove and the associated hold-and-retain portion, whereby
the reel urging member is fitted on the upper half. The upper half
thus fitted with the reel urging member, the lower half, the front
cover and any other required members and components are fitted and
combined to assemble the magnetic tape cassette having the
above-mentioned reel urging member.
[0200] To disassemble the cassette of the invention, the following
procedure may be taken. The case is broken down so that the upper
half is uncoupled from the lower half and the tape reel contacting
portion of the reel urging member fitted on the upper half is
pulled to extract the sliding end portions of the reel urging
member each of which has been inserted between the inner bottom
surface of the slide groove and the associated hold-and-retain
portion; in this way, the reel urging member can be easily
separated and dislodged from the upper half. In the first aspect of
the invention, the window member is adapted to be removable from
the window opening in the upper half and, hence, the reel urging
member can be easily dislodged when the window member is removed
from the window opening in the upper half.
[0201] FIGS. 1-5 illustrate an exemplary design for the structures
of the reel urging member and the upper half of the magnetic tape
cassette according to the first aspect of the invention. The
constituent elements of the cassette according to the first aspect
of the invention excepting those indicated by reference numerals in
FIGS. 1-5 are not limited in any particular way and may be the same
as those used in the prior art magnetic tape cassette shown in FIG.
53; hence, those constituent elements are not shown specifically in
FIGS. 1-5, nor are they explained in the following description.
[0202] FIG. 1 is a perspective view showing the inner surface of an
example of the upper half of the magnetic tape cassette. In the
magnetic tape cassette shown in FIG. 1, the reel urging member
generally indicated by 1 urges the tape reel in the case toward the
lower half.
[0203] As shown in FIGS. 1 and 4, the reel urging member 1 has a
tape reel contacting portion 3, generally of an inverted V shape in
cross section, that is brought into contact with the upper part of
the tape reel, bent arms 5a and 5b connecting to opposite sides of
the tape reel contacting portion 3, and sliding end portions 7a and
7b which are at the distal ends of the bent arms 5a and 5b,
respectively.
[0204] As shown in FIG. 2A and FIG. 2B which is a partial enlarged
view of FIG. 2A, the upper half 9 has a window opening 11 and the
inner surface 13 on its perimeter has a slide groove 15 into which
the sliding end portions 7a and 7b of the reel urging member 1 will
be inserted. The slide groove 15 traverses the center of the tape
reel housed in the case and it is made in the inner surface 13 of
the perimeter of the opening 11 to extend toward the front and rear
sides of the upper half 9 such that the tape reel contacting
portion 3 of the reel urging member 1 whose sliding end portions 7a
and 7b are to be inserted into the slide groove 15 will contact the
center of the reel hub in the tape reel. The sliding end portions
7a and 7b of the reel urging member 1 are inserted into the slide
groove 15 and, after being located in the front and rear slide
grooves 17a and 17b which are on opposite sides of the center in
the longitudinal direction of the slide groove 15, the sliding end
portions 7a and 7b slide on the inner bottom surfaces of the front
and rear slide grooves 17a and 17b.
[0205] As shown in FIG. 3, the transparent window member 19 which
is to be fitted in the window opening 11 has hold-and-retain
portions 21a and 21b that are to be placed on the lower surfaces of
the front and rear slide grooves 17a and 17b along which the
sliding end portions 7a and 7b of the reel urging member 1 as
inserted into the slide groove 15 will slide and which hold the
sliding end portions 7a and 7b in cooperation with the inner bottom
surfaces of the front and rear slide grooves 17a and 17b. The
distal ends 23a and 23b of the hold-and-retain portions 21a and 21b
are fitted in a stepped area 25 formed along the slide groove 15 in
the inner surface of the upper half 9.
[0206] When the tape reel in the magnetic tape cassette having the
upper half as it has been fitted with the reel urging member 1 of
the design shown in FIG. 1 depresses the tape reel contacting
portion 3 of the reel urging member 1 toward the upper half as it
contacts the tape reel, for example, in the case where the magnetic
tape cassette is loaded in the record/reproduce apparatus and the
tape drive unit is fitted in the lower part of the tape reel so
that the latter is depressed toward the upper half 9, the tape reel
contacting portion 3 is depressed toward the upper half 9 and the
sliding end portions 7a and 7b of the bent arms 5a and 5b slide on
the inner bottom surfaces of the front and rear slide grooves 17a
and 17b toward the front and rear ends of the slide groove 15 as
the bent arms 5a and 5b deform to spread, whereupon the tape reel
is urged toward the lower half.
[0207] To assemble the magnetic tape cassette having the upper half
fitted with the reel urging member shown in FIG. 1, the following
procedure may be taken. The window member 17 shown in FIG. 3 is
fitted in the window opening 11 in the upper half 9 and the distal
ends 23a and 23b of the hold-and-retain portions 21a and 21b of the
window member 17 are fitted in the stepped area 25; then, the
sliding end portion 7a (or 7b) of the reel urging member 1 shown in
FIG. 4 is inserted between the inner bottom surface of the front
slide groove 17a (or the rear slide groove 17b) and the
hold-and-retain portion 21a (or 21b), whereby the reel urging
member 1 is fitted on the upper half 9. The upper half 9 thus
fitted with the reel urging member 1, the lower half, the front
cover and any other required members and components are fitted and
combined to assemble the magnetic tape cassette having the
above-mentioned reel urging member 1.
[0208] To disassemble the magnetic tape cassette under
consideration, the following procedure may be taken. The case is
broken down so that the upper half is uncoupled from the lower half
and the tape reel contacting portion 3 of the reel urging member 1
fitted on the upper half is pulled to extract the sliding end
portion 7a (or 7b) of the reel urging member 1 which has been
inserted between the inner bottom surface of the front slide groove
17a (or the rear slide groove 17b) and the hold-and-retain portion
21a (or 21b); in this way, the reel urging member 1 can be easily
separated and dislodged from the upper half 9.
[0209] FIG. 5 is a perspective view showing the inner surface of
the upper half of another example of the cassette according to the
first aspect of the invention.
[0210] The magnetic tape cassette shown in FIG. 5 is such that the
upper half 27 has the window opening 11 in either the right or left
area of the upper plate 29 but has no window opening in the other
area. The reel urging member 1 shown in FIG. 4, particularly its
sliding end portions 7a and 7b, are inserted into the slide groove
15 made in the inner surface 13 of the perimeter of the window
opening 11, and a reel urging member 31 different from the reel
urging member 1 is provided in the area of the upper plate 29 which
has no window opening.
[0211] The reel urging member 1 in the upper half 27, the slide
groove 15, the window member to be fitted in the window opening 11,
the hold-and-retain member associated with the window member and
the stepped area 25, as well as their structures,
interrelationships and actions are identical to those illustrated
in FIGS. 1-4; hence, the members and sites which are identical to
those shown in FIGS. 1-4 are identified by like numerals and will
not be described in detail.
[0212] The reel urging member 31 has a tape reel contacting portion
33, generally of an inverted V shape in cross section, that is
brought into contact with the upper part of the tape reel, bent
arms 35a and 35b connecting to opposite sides of the tape reel
contacting portion 33, and sliding end portions 37a and 37b which
are at the distal ends of the bent arms 35a and 35b,
respectively.
[0213] The reel urging member 31 is provided on the inner surface
39 of the upper half 27; the reel urging member 31 traverses the
center of the tape reel housed in the case and it extends toward
the front and rear sides of the upper half 27 such that the tape
reel contacting portion 33 will contact the center of upper part of
the reel hub in the tape reel. The sliding end portions 37a and 37b
of the reel urging member 31 are inserted such that they come into
engagement with engage-and-stop portions 41a and 41b erected on the
inner surface 39.
[0214] The engage-and-stop portions 41a and 41b have insertion
holes through which the sliding end portions 37a and 37b are to be
fitted.
[0215] When the tape reel depresses the tape reel contacting
portion 33 of the reel urging member 31 toward the upper half as it
contacts the tape reel, for example, in the case where the magnetic
tape cassette is loaded in the record/reproduce apparatus and the
tape drive unit is fitted in the lower part of the tape reel so
that the tape reel is depressed toward the upper half 27, the tape
reel contacting portion 33 is depressed toward the upper half 27
and the sliding end portions 37a and 37b of the bent arms 35a and
35b in engagement with the engage-and-stop portions 41a and 41b,
respectively, slide on the inner surface of the upper half 27 as
the bent arms 35a and 35b deform to spread, whereupon the tape reel
is urged toward the lower half.
[0216] To assemble the magnetic tape cassette having the upper half
27 fitted with the reel urging members 1 and 31 shown in FIG. 5,
the following procedure may be taken. The window member 17 shown in
FIG. 3 is fitted in the window opening 11 in the upper half 27 and
the distal ends 23a and 23b of the hold-and-retain portions 21a and
21b of the window member 17 are fitted in the stepped area 25;
then, the sliding end portion 7a (or 7b) of the reel urging member
1 shown in FIG. 4 is inserted between the inner bottom surface of
the front slide groove 17a (or the rear slide groove 17b) and the
hold-and-retain portion 21a (or 21b), whereby the reel urging
member 1 is fitted on the upper half 27. In addition, the sliding
end portions 37a and 37b of the reel urging member 31 are inserted
into the engage-and-stop portions 41a and 41b, respectively,
whereby the reel urging member 31 is fitted on the upper half 27.
The upper half 27 thus fitted with the reel urging members 1 and
31, the lower half, the front cover and any other required members
and components are fitted and combined to assemble the magnetic
tape cassette having the above-mentioned reel urging members 1 and
31.
[0217] To disassemble the magnetic tape cassette under
consideration, the following procedure may be taken. The case is
broken down so that the upper half is uncoupled from the lower half
and the tape reel contacting portion 3 of the reel urging member 1
fitted on the upper half 27 is pulled to extract the sliding end
portion 7a (or 7b) of the reel urging member 1 which has been
inserted between the inner bottom surface of the front slide groove
17a (or the rear slide groove 17b) and the hold-and-retain portion
21a (or 21b); further, the tape reel contacting portion 33 of the
reel urging member 31 is pulled to extract the sliding end portions
37a and 37b from within the engage-and-stop portions 41a and 41b,
respectively; in this way, the reel urging members 1 and 31 can be
easily separated and dislodged from the upper half 27.
[0218] Described above are the basic structural features of the
magnetic tape cassette according to the first aspect of the
invention.
[0219] We now describe the magnetic tape cassette according to the
second aspect of the invention with reference to FIGS. 6-9.
[0220] The magnetic tape cassette according to the second aspect of
the invention uses a leaf-like spring as the reel urging spring. It
has a kinky shape and the kink may be a generally inverted V shape,
mesa-shaped, arcuate or of any other cross-sectional shape;
depending on shape, any point such as the crest or a point halfway
the bent arm is brought into contact with the upper part of the
tape reel, say, the reel hub so that the tape reel is depressed and
thereby urged toward the lower half.
[0221] The reel urging spring has an engagement hole at an end and
an engage-and-stop grooved portion at the other end. The engagement
hole comes into engagement with an engaging pin erected on the
inner surface of the upper half, whereby the end of the reel urging
spring having this hole is constrained in movement relative to the
upper half and it becomes the fixed end of the reel urging spring.
The engaging pin may be erected on a lip-like step that is formed
on the inner surface of the upper half such that it can be torn
off. This is a preferred embodiment since the cassette case is
sufficiently thin in the lip-like step area that the reel urging
member can be taken out of the case without breaking it down but by
simply applying pressure from the outside to split the lip-like
step open. More preferably, the lip-like step is formed by making a
cutout in the upper plate of the upper half since this provides
ease in applying pressure from the outside of the case to split the
lip-like step open.
[0222] The engage-and-stop pin erected on the inner surface of the
upper half is fitted loosely into the engage-and-stop grooved
portion so that it has free play along the length of the
engage-and-stop grooved portion. In consequence, as the reel urging
spring flexes in the vertical direction, the engage-and-stop
grooved portion moves in the longitudinal direction of the reel
urging spring, constantly giving an appropriate urging force to the
tape reel.
[0223] The engage-and-stop grooved portion is formed along the
length of the reel urging spring and its other end preferably has a
split shape which is open at the distal end. This is an effective
design since if pressure is applied to the aforementioned lip-like
step from the outside to split it open and the other end of the
reel urging spring is extracted, the reel urging spring can be
easily dislodged from the upper half without breaking down the
case.
[0224] If desired, the cassette according to the second aspect of
the invention may have a temporary locking recess on the straight
line connecting the engaging pin and the engage-and-stop pin on the
inner surface of the upper half and in a position closer to the
engage-and-stop pin such that the engaging pin is fitted into the
engagement hole and secured in position before the upper half is
coupled to the lower half while at the same time the
engage-and-stop end of the reel urging spring is brought into
engagement with the temporary locking recess, thereby allowing the
reel urging spring to be locked temporarily to the upper half. If
the upper half to which the reel urging spring has been locked
temporarily is coupled to the lower half to assemble the cassette
case with the tape reel in it, the reel urging spring contacts the
upper part of the tape reel which then depresses the reel urging
spring so that its engage-and-stop end is no longer in temporary
engagement with the temporary locking recess but moves toward the
engage-and-stop pin until it comes into engagement with the
engage-and-stop pin. This offers the advantage of not only
facilitating the work of mounting the reel urging spring during the
process of assembling the cassette of the invention but also
providing ease in removing the reel urging spring in the process of
assembly in order to break down the cassette case or re-mounting it
in order to assemble the case.
[0225] FIGS. 6-9 illustrate an exemplary design for the structures
of the upper half and the leaf-like reel urging spring in the
magnetic tape cassette according to the second aspect of the
invention. The following description mainly concerns the upper half
and the reel urging spring and the other constituent elements (e.g.
members and components) of the magnetic tape cassette such as the
constituent elements (e.g. members and components) other than the
upper half and the reel urging spring in the magnetic tape cassette
illustrated in FIG. 53 are not limited in any particular way and
may be the same as those used in the prior art magnetic tape
cassette shown in FIG. 53; hence, those constituent elements are
not shown specifically in FIGS. 6-9, nor are they explained in the
following description.
[0226] FIG. 6A is a plan view showing an exemplary design for the
structures of the upper half and the reel urging spring in the
magnetic tape cassette according to the second aspect of the
invention. FIG. 6B is section A-A of FIG. 6A.
[0227] In FIG. 6A, two reel urging springs 55 in the form of a
kinky leaf are shown to be fitted on the inner surface 53 of the
upper half 51.
[0228] As shown in FIG. 7A, the leaf-like reel urging spring 55 is
of an inverted V shape in cross section which is kinky with a crest
57 in the middle; it has an engagement hole 59 at an end and an
engage-and-stop grooved portion 63 at the other end which is split
to form a groove 61 that permits free play.
[0229] As shown in FIGS. 6A and 6B, the inner surface 53 of the
upper half 51 has a lip-like step 65 and this forms a recess in the
inner surface 53 since a cutout 67 is provided on its perimeter and
since the lip-like step 65 is thin-walled. An engaging pin 69 is
erected on the lip-like step 65 such that it comes into engagement
with the engagement hole 59. The lip-like step 65 has a smaller
wall thickness than the upper plate of the upper half in the
surrounding area; in addition, it has the cutout 67 on the
perimeter and, hence, the lip-like step 65 can be easily split to
open by applying pressure to the upper half from the outside (from
the other side of the paper) and the remaining part of the lip-like
step 65 can be easily torn off, which is indeed a preferred
embodiment of the invention.
[0230] An engage-and-stop pin 71 is also erected on the inner
surface 53 of the upper half 51 and this pin is loosely fitted into
the free play groove 61 in the engage-and-stop grooved portion 63
which is provided at the other end of the reel urging spring 55.
When the engage-and-stop pin 71 is loosely fitted into the free
play groove 61, the engage-and-stop grooved portion 63 constrains
the direction of action of the reel urging spring 55 such that it
is free to move along the engage-and-stop grooved portion 63 only
in the longitudinal direction.
[0231] In the magnetic tape cassette under consideration which has
the upper half 51 and the leaf-like reel urging spring 55, the
crest 57 of the reel urging spring 55 contacts the upper part of
the tape reel rotatably housed in the interior of the case formed
by coupling the upper and lower halves and the tape reel is urged
toward the lower half, with the crest 57 working as the apex. In
this situation, the engaging pin 69 is fitted into the engagement
hole 59 in the reel urging spring 55 and secured in position;
hence, the end of the reel urging spring 55 at which the engagement
hole 59 is made is constrained in movement relative to the upper
half 51 and becomes the fixed end of the latter.
[0232] The engage-and-stop pin 71 erected on the inner surface of
the upper half 51 is fitted loosely into the free play groove 61 in
the engage-and-stop grooved portion 63 and brought into engagement
such that it is free to move along the length of the free play
groove 61. In consequence, as the reel urging spring 55 flexes in
the vertical direction, the engage-and-stop grooved portion 63
moves in the longitudinal direction of the reel urging spring,
constantly giving an appropriate urging force to the tape reel.
[0233] To disassemble the magnetic tape cassette under
consideration, pressure may be applied to the lip-like step 65 from
the outside of the upper half 51 until it splits open; the lip-like
step 65 is then pulled out to take the reel urging spring 55 from
within the upper half 51. The lip-like step 65 has a smaller wall
thickness than the upper plate of the upper half in the surrounding
area; in addition, it has the cutout 67 on the perimeter and,
hence, the lip-like step 65 can be easily split open by applying
pressure to the upper half from the outside (from the other side of
the paper) and the remaining part of the lip-like step 65 can be
easily torn off. In addition, the free play groove 61 in the
engage-and-stop grooved portion 63 has a split shape that is open
at the distal end of the engage-and-stop grooved portion 63;
therefore, the reel urging spring 55 can be smoothly pulled out of
the upper half without letting the other end of the reel urging
spring 55 to get stuck on the engage-and-stop pin 71.
[0234] As a result, the metallic reel urging spring 55 can be
easily dislodged from the cassette case without breaking it
down.
[0235] FIG. 7B illustrates another example of the leaf-like reel
urging spring which is different from the one shown in FIG. 7A.
[0236] The leaf-like reel urging spring indicated by 73 in FIG. 7B
is similar to the reel urging spring 55 shown in FIG. 7A which has
an inverted V shape in cross section, in that it has an engagement
hole 75 at one end into which the engaging pin on the upper half is
to be fitted and secured in position whereas it has an
engage-and-stop grooved portion 79 at the other end with a split
shape at the distal end having a free play groove 77; the
difference is that the leaf-like urging spring 73 is mesa-shaped in
cross section which is kinky with a flat crest 81. Except for the
crest 81, the reel urging spring 73 performs in the same way, has
the same function and achieves the same effect as the reel urging
spring 55 shown in FIG. 7A.
[0237] In the cases shown in FIGS. 6 and 7, the apex 57 of the
leaf-like reel urging spring 55 which has an inverted V shape in
cross section or the flat crest 81 of the leaf-like reel urging
spring 73 which is mesa-shaped in cross section contacts the upper
part of the tape reel, say, the upper part of the reel hub.
However, there is no particular limitation on the site at which the
reel urging spring in the cassette of the invention contacts the
tape reel and any part of the reel urging spring may contact the
tape reel. For example, the reel urging spring 55 shown in FIG. 7A
may contact the tape reel at a site halfway between the engagement
hole 9 and the apex 57 or at a site halfway between the
engage-and-stop grooved portion 63 and the apex 57.
[0238] FIG. 8 illustrates still another example of the upper half
of the cassette according to the second aspect of the invention.
The upper half indicated by 83 in FIG. 8 has a temporary locking
recess 89 on the straight line connecting an engaging pin 85 and an
engage-and-stop pin 87 and in a position closer to the
engage-and-stop pin 87.
[0239] As shown in FIG. 9A, the magnetic tape cassette using the
upper half 83 has the engaging pin 85 fitted into the engagement
hole 93 in the leaf-like reel urging spring 91 to provide a fixed
end while at the same time the distal end 95 of the engage-and-stop
grooved portion 94 of the reel urging spring 91 is brought into
temporary engagement with the temporary locking recess 89, thereby
allowing the reel urging spring 91 to be locked temporarily to the
upper half 83. If the upper half 83 to which the reel urging spring
91 has been locked temporarily is coupled to the lower half (not
shown) to construct the cassette case with the tape reel in it, the
reel urging spring 91 contacts the upper part of the tape reel
which then depresses the reel urging spring 91 so that it comes out
of temporary engagement with the temporary locking recess 89; then,
as shown in FIG. 9B, the engage-and-stop grooved portion 94 moves
toward the engage-and-stop pin 87 until it is loosely fitted into
the free play groove 97 to allow free movement in the longitudinal
direction.
[0240] The foregoing design enables the manufacturer of the
magnetic tape cassette to perform various operations with the
leaf-like reel urging spring locked temporarily to the upper half
and this offers the advantage of not only facilitating the work of
mounting the reel urging spring during the assembling process but
also providing ease in removing the reel urging spring in the
process of assembly in order to break down the cassette case or
re-mounting it in order to assemble the case.
[0241] Described above are the basic structural features of the
magnetic tape cassette according to the second aspect of the
invention.
[0242] Before describing the tape reel that can be broken down
according to the third to fifth aspects of the invention, as well
as the resinous leaf spring according to the sixth aspect of the
invention and the process for producing it, we will continue to
describe the magnetic tape cassette of the invention as it concerns
the seventh to tenth aspects of the invention.
[0243] The magnetic tape cassette according to the seventh aspect
of the invention is described below with reference to FIGS.
10-12.
[0244] In the magnetic tape cassette according to the seventh
aspect of the invention, the reel urging member comprises a base
portion which is to be secured to the inner surface of the upper
half and a tape reel contacting portion in the form of an inclined
plane connecting to an end of the base portion via a bent portion.
When the tape reel contacting portion contacts the upper part of
the tape reel, the bent portion will deform under the pressure
exerted by the tape reel and the resiliency against this
deformation causes the tape reel to be urged toward the lower half.
Generally speaking, the angle .theta. the base portion of the reel
urging member forms with the tape reel contacting portion at the
bent portion is preferably in the range of 5-70 degrees and from
the viewpoint of causing the tape reel to be pressed against the
lower half by spring force, a particularly preferred range is 20-60
degrees. If .theta. is excessive, difficulty may be encountered in
mounting the tape reel.
[0245] The upper half can be secured to the base portion by any
methods without particular limitation. Exemplary methods that can
be used include welding and bonding.
[0246] In the seventh aspect under consideration, the tape reel
contacting portion of the reel urging member is a site which
contacts the upper part of the tape reel, particularly the crest of
the reel hub, when the tape reel is housed in a cassette case
constructed by coupling the upper and lower halves. The tape reel
contacting portion may have any cross-sectional shape as
exemplified by a flat plate and it may be of such a shape that it
contacts the upper part of the tape reel at one or more sites. The
tape reel contacting portion (107) may have a recess (113) at a
site which contacts the crest (119) of the reel hub (117) such that
the crest (119) can be fitted into the recess (113); this design is
effective since it enables the tape reel to be supported in a
stable manner. The tape reel contacting portion (125) may further
be provided with a contacting area (129) that is bent in a U shape
in cross section which is convex toward the base portion (127) and
the distal end of which contacts the base portion (127). This
design is preferred since it can not only control the spring force
but also minimize the effect that is exerted on the spring force by
the means of mounting the base portion (127) to the upper half.
[0247] Further in addition, a convex or a ridge (131) may be
provided on the side of the base portion (127) which faces the tape
reel contacting portion (125); this is a more effective design
since the pressing force exerted upon the tape reel can be further
stabilized by bending the tape reel contacting portion (125) until
it contacts the ridge (131).
[0248] FIGS. 10-12 illustrate an exemplary design for the
structures of the reel urging member and the upper half of the
magnetic tape cassette according to the seventh aspect of the
invention. The constituent elements of the cassette according to
the seventh aspect of the invention excepting those indicated by
reference numerals in FIGS. 10-12 are not limited in any particular
way and may be the same as those used in the prior art magnetic
tape cassette shown in FIG. 53; hence, those constituent elements
are not shown specifically in FIGS. 10-12, nor are they explained
in the following description.
[0249] FIG. 10 is a perspective view showing the inner surface of
an example of the upper half to be used in the seventh aspect of
the invention. In the upper half generally indicated by 101 in FIG.
10, the reel urging member generally indicated by 103 urges the
tape reel (not shown) in the case toward the lower half.
[0250] As shown in FIGS. 10 and 11, the reel urging member 103 is
generally of a V shape in cross section, specifically of a V shape
with one side lying horizontally, and has a base portion 105 in the
form of a flat plate and a tape reel contacting portion 107 also in
the form of a flat plate which connects to an end of the base
portion 105 via a bend 106 at angle .theta.. The base portion 105
has a mounting portion 109 and the tape reel contacting portion 107
has a recess 113 formed in the surface 111 at the center.
[0251] As shown in FIG. 11, the magnetic tape cassette has the reel
urging member 103 mounted on the inner surface 121 of the upper
half 101 by welding the mounting portion 109 of the base portion
105 such that the crest 119 of the reel hub 117 in the tape reel
115 will be in a position where it fits into the recess 113.
[0252] When the upper half 101 having the reel urging member 103
mounted on the inner surface and the lower half (not shown) are
coupled to construct a cassette case with the tape reel in it, the
crest 119 of the reel hub 117 in the tape reel 115 causes the tape
reel contacting portion 107 in contact with the crest 119 to be
pressed toward the upper half 101 (see FIG. 11), whereupon the bend
106 deforms elastically and its resiliency causes the tape reel 115
to be urged toward the lower half (downward in FIG. 11).
[0253] FIG. 12 illustrates another example of the seventh aspect of
the invention. In the illustrated example, the reel urging member
generally indicated by 123 is essentially the same as what is shown
in FIGS. 10 and 11, except that the tape reel contacting portion
125 is provided with a contacting area 129 that is bent in a U
shape in cross section which is convex toward the base portion 127
and the distal end of which contacts the base portion 127; another
difference is that a ridge 131 is provided on the side of the base
portion 127 which faces the tape reel contacting portion 125. This
design is preferred since it can not only control the spring force
but also minimize the effect that is exerted on the spring force by
the means of mounting the base portion 127 to the upper half.
[0254] Described above are the basic features of the magnetic tape
cassette according to the seventh aspect of the invention.
[0255] We next describe the magnetic tape cassette according to the
eighth aspect of the invention with reference to FIGS. 13-15.
[0256] In the eighth aspect of the invention, the reel urging
member contacts the tape reel and deforms elastically in a
direction generally perpendicular to the direction of urging the
reel, thereby causing the tape reel to be urged toward the lower
half. In the eighth aspect of the invention, the direction of
urging the reel is from the upper half toward the lower half;
elastic deformation in a direction generally perpendicular to the
direction of urging the reel means that flexible ribs deform
elastically by bending through angles within 90 degrees either
inwardly (as shown in FIG. 13B) or outwardly (as in FIG. 15B) with
respect to the direction of urging the reel.
[0257] In the eighth aspect of the invention, the reel urging
member is one of the following types: (1) it comprises flexible
ribs erected on the inner surface of the upper half to extend
toward the lower half and a contact member that is fitted over the
distal ends of the flexible ribs; (2) it comprises flexible ribs
erected on the inner surface of the upper half to extend toward the
lower half, with a recess in the form of an inverted cone being
made in the upper surface of the tape reel such that the distal
ends of the flexible ribs are to be inserted into the recess; or
(3) it consists of any other shapes that permit the tape reel to be
urged toward the lower half by elastic deformation of flexible
ribs.
[0258] In the eighth aspect of the invention, the flexible ribs are
erected on the inner surface of the upper half such that they
extend toward the lower half from positions that are determined by
the positions where the tape reels are housed in the cassette case.
The flexible ribs may take any shapes including a pair of ribs that
are erected parallel on the inner surface of the upper half.
[0259] The flexible ribs each have an engage-and-stop end portion
at the distal end which is to be either fitted into a fitting
portion that is formed by the inclined inner surface of a
downwardly convex contact member having a generally U shaped cross
section or inserted into a recess in the form of an inverted cone
that is made in the upper surface of the tape reel; the
engage-and-stop end portions preferably have sliding ends that
slide in contact with the inclined inner surface of the fitting
portion or the recess. It is also preferred that the flexible ribs
which are to be fitted into the contact member have engage-and-stop
shoulders that come into engagement with an engage-and-stop flange
formed at the upper edge of the inclined inner surface of the
contact member.
[0260] In the cassette of the eighth aspect of the invention, the
reel urging member may be composed of flexible ribs and a contact
member. If the upper half of this design is assembled, the
engage-and-stop shoulders of the engage-and-stop end portions at
the distal ends of the flexible ribs as fitted into the fitting
area of the contact member come into engagement with the
engage-and-stop flange formed at the upper edge of the contact
member. The upper half fitted with this reel urging member is
coupled with the lower half to construct the cassette case. When
the tape reel is housed in the cassette case, the crest at the
lower part of the contact member is brought into contact with the
upper part of the tape reel. As a result of this contact, the reel
urging member is depressed by the tape reel, whereupon the contact
member is pressed upward; in response to the developed pressing
force, the sliding ends of the flexible ribs slide on the U-shaped,
inclined inner surface of the contact member, causing the flexible
ribs to deform elastically by bending in a direction generally
perpendicular to the direction of urging the tape reel; this
elastic deformation develops a drive force that urges the tape reel
toward the lower half.
[0261] Alternatively, the reel urging member may be composed of
flexible ribs, with a recess being formed in the upper part of the
tape reel such that the flexible ribs are inserted into the recess.
The upper half fitted with the flexible ribs on the inner surface
is coupled with the lower half to construct the cassette case. When
the tape reel having the recess formed in the upper part is housed
in the cassette case, the distal ends of the flexible ribs are
inserted into the recess in the upper part of the tape reel. As a
result of this contact, the flexible ribs are pressed upward; in
response to the developed pressing force, the flexible ribs deform
elastically by bending in a direction generally perpendicular to
the direction of urging the tape reel; this elastic deformation
develops a drive force that urges the tape reel toward the lower
half.
[0262] In the cassette according to the eighth aspect of the
invention, the reel urging member is provided on the inner surface
of the upper half in a position where it urges the tape reel and
which is determined by where in the cassette case the tape reel is
to be housed. For instance, it may be provided on the inner surface
of the upper half at a site which corresponds to an upper part
where the reel hub in the tape reel is to be located.
[0263] If the flexible ribs and the contact member combine to form
the reel urging member, the cross-sectional shape of the contact
member is not limited in any particular way and it may be of an
inverted cone, one of the two longitudinally split sections of a
tube or any other shape that has an inclined inner surface
describing a U-shaped cross section which makes slidable contact
with the distal ends of the flexible ribs. In a particularly
preferred case, the contact member has a cross-sectional shape of
one of the two longitudinally split sections of a tube.
[0264] If the recess into which the distal ends of the flexible
ribs are to be inserted is made in the upper part of the tape reel,
the shape of the recess is not limited in any particular way and it
may be of any shape such as an inverted cone or one of the two
longitudinally split sections of a tube.
[0265] If the reel urging member of the cassette according to the
eighth aspect of the invention is composed of flexible ribs and a
contact member into which the flexible ribs are to be fitted, both
the flexible ribs and the contact member may be formed of a resin
material. In particular, the flexible ribs may be formed of the
same resin material as the upper half of which it is an integral
part; alternatively, they may be formed of a different resin
material than the upper half. If the contact member is formed of
the same resin material as the upper half and the flexible ribs,
the upper half need not be broken down into the respective parts
and this is effective for the purpose of assorted collection of
resin materials.
[0266] If the reel urging member is composed of flexible ribs and a
recess is formed in the upper part of the tape reel such that the
flexible ribs are inserted into the recess, the flexible ribs may
again be formed of the same resin material as the upper half of
which it is an integral part; alternatively, they may be formed of
a different resin material than the upper half. If the flexible
ribs are formed of the same resin material as the upper half, the
upper half need not be broken down into the respective parts and
this is effective for the purpose of assorted collection of resin
materials.
[0267] FIGS. 13-15 illustrate an exemplary design for the
structures of the reel urging member and the upper half of the
magnetic tape cassette according to the eighth aspect of the
invention. The constituent elements of the cassette according to
the eighth aspect of the invention excepting those indicated by
reference numerals in FIGS. 13-15 are not limited in any particular
way and may be the same as those used in the prior art magnetic
tape cassette shown in FIG. 53; hence, those constituent elements
are not shown specifically in FIGS. 13-15, nor are they explained
in the following description.
[0268] FIG. 13A is a schematic cross-sectional view of the reel
urging member which is generally indicated by 151 and which urges
the tape reel in the case toward the lower half.
[0269] The reel urging member 151 has a pair of flexible ribs 157a
and 157b and a contact member 159. The flexible ribs are erected
parallel on the inner surface 155 of the upper half 153 to extend
toward the lower half (not shown), and the contact member 159 is
one of the two longitudinally split sections of a tube which is
oriented convex downward to be fitted over the distal ends of the
flexible ribs 157a and 157b.
[0270] The flexible ribs 157a and 157b have engage-and-stop end
portions 161a and 161b, respectively, at the distal ends. The
engage-and-stop end portion 161a (or 161b) has an engage-and-stop
shoulder 165a (or 165b) that engages an engage-and-stop flange 163
formed at the upper edge of the contact member 159, as well as a
sliding end portion 171a (or 171b) that slides in contact with the
inclined inner surface 169 of a U-shaped cross section which faces
the fitting area 167 inside of the contact member 159.
[0271] If the upper half fitted with the reel urging member 151 is
assembled, the engage-and-stop shoulders 165a and 165b of the
engage-and-stop end portions 161a and 161b at the distal ends of
the flexible ribs 157a and 157b as fitted into the fitting area 167
of the contact member 159 come into engagement with the
engage-and-stop flange 163 formed at the upper edge of the contact
member 159.
[0272] The upper half fitted with this reel urging member 151 is
coupled with the lower half to construct the cassette case. When
the tape reel is housed in the cassette case, the crest 173 at the
lower part of the contact member 159 is brought into contact with
the upper part of the tape reel (indicated by the short-and-long
dashed line in FIG. 13B). As a result of this contact, the reel
urging member 151 is depressed by the tape reel, whereupon the
contact member 159 is pressed upward; in response to the developed
pressing force, the sliding end portions of 171a and 171b of the
flexible ribs 157a and 157b slide on the U-shaped, inclined inner
surface 169 of the contact member 159, causing the two flexible
ribs 157a and 157b to deform elastically by bending inwardly in
opposite directions; this elastic deformation develops a drive
force that urges the contact member 159 toward the tape reel.
[0273] In the magnetic tape cassette having the reel urging member
151, the reel urging member is provided on the inner surface of the
upper half in a position where it urges the tape reel and which is
determined by where in the cassette case the tape reel is to be
housed. Consider, for example, a two-reel type magnetic tape
cassette; as in the exemplary design illustrated in FIG. 14, the
reel urging member generally indicated by 179 which is composed of
flexible ribs 175 and a contact member 177 may be provided on the
inner surface 183 of the upper half 181 at two sites where the reel
hub in the tape reel is to be located.
[0274] FIG. 15 is a schematic cross-sectional view illustrating
another exemplary design for the reel urging member in the cassette
according to the eighth aspect of the invention.
[0275] The reel urging member generally indicated by 185 consists
of a pair of flexible ribs 187a and 187b which are erected parallel
on the inner surface (not shown) of the upper half to extend toward
the lower half, with a recess 195 in the form of an inverted cone
being made in the upper surface 191 of the tape reel 189 such that
the distal ends 193a and 193b of the flexible ribs 187a and 187b
are to be inserted into the recess.
[0276] The flexible ribs 187a and 187b have sliding end portions
199a and 199b that contact the inclined inner surface 197, in the
form of an inverted cone, of the recess 195 in the tape reel
189.
[0277] When the upper half fitted with the flexible ribs 187a and
187b that combine together to form the reel urging member is
coupled with the lower half to construct the cassette case as it
contains the tape reel, the distal ends 193a and 193b of the
flexible ribs 187a and 187b are inserted into the recess 195 in the
upper surface 191 of the tape reel 189, whereupon the sliding end
portions 199a and 199b come into contact with the inclined inner
surface 197 of the recess 195. As a result of this contact, the
flexible ribs 187a and 187b are pressed upward by the tape reel
189; in response to the developed pressing force, the sliding end
portions 199a and 199b of the flexible ribs 187a and 187b keep
contacting the inclined inner surface 197 of the recess 195 and, as
shown in FIG. 15B, the flexible ribs 187a and 187b bend in the
direction of arrow A and deform elastically in a direction
generally perpendicular to the direction of urging the tape reel
189; this elastic deformation develops a drive force that urges the
tape reel 189 toward the lower half.
[0278] In the magnetic tape cassette having the flexible ribs 187a
and 187b as reel urging members, those flexible ribs 187a and 187b
are provided on the inner surface of the upper half in such
positions that they urge the tape reel 189 and these positions are
determined by where the tape reel 189 is housed within the cassette
case.
[0279] The reel urging members illustrated in FIG. 13A and 15A have
a simple and straightforward structure and are yet capable of
adequately urging the tape reel toward the lower half; what is
more, they can be formed of a resin material instead of a metal
material. Hence, the magnetic tape cassette having these reel
urging members are advantageous for assorted collection of resin
material.
[0280] Described above are the basic features of the design for the
magnetic tape cassette according to the eighth aspect of the
invention.
[0281] We now describe a magnetic tape cassette according to the
ninth aspect of the invention with reference to FIGS. 16-20.
[0282] The following description concerns the case of applying the
ninth aspect of the invention to a two-reel type magnetic tape
cartridge (magnetic tape cassette).
[0283] FIG. 16A is a perspective view of a magnetic tape cassette
according to an example of the ninth aspect of the invention, and
FIG. 17 shows in section a reel urging spring insertion area of the
magnetic tape cassette shown in FIG. 16A. In FIGS. 16A and 17, no
parts of the magnetic tape cassette that are irrelevant to the
ninth aspect of the invention are shown. In the following
description, the overall construction of the magnetic tape cassette
already described with reference to FIG. 53 is omitted and only the
essential parts will be described.
[0284] In the example shown in FIG. 17, reel urging spring
insertion areas 210 are each provided in the upper half 200 at a
specified position in a hook (crank) shape that penetrates the
upper half 200. To be more exact, each of the reel urging spring
insertion areas 210 as provided in the upper half 200 at specified
positions consists of two staggered recesses 211 and 212, one of
which faces the bottom surface (inner surface) of the upper half
200 and the other facing the outer surface (upper surface). The two
recesses 211 and 212 connect to each other as they are spaced apart
by a small distance.
[0285] In the example under consideration, the leaf-like reel
urging spring 220 is typically of the shape shown in FIG. 17 and
consists of an insertion part having two hairpin-like bends 222
which are U-shaped in opposite directions and a flat portion 224 at
the terminal end of the bend 222, and an elastic portion 223
provided in the distal end portion of the bend 222. The bend 222
has been worked to exhibit a specified degree of spring elasticity
when the flat portion 224 of the reel urging spring 220 makes face
contact with the bottom surface of the recess 211 and when the bend
222 as inserted into the reel urging spring insertion area 210
makes face contact with both lateral surfaces of the recess
212.
[0286] FIG. 18 illustrates the reel urging spring 220 as it has
been taken out of the reel urging spring insertion area 210.
[0287] As FIG. 18 shows, the bend 222 of the reel urging spring 220
taken out of the reel urging spring insertion area 210 has spread
considerably than when it was inserted into the reel urging spring
insertion area 210. To be more specific, in the example under
consideration, the reel urging spring 220 having the bend 222 of
size d (the width of the bend in the natural state) shown in FIG.
18 is compressed by a certain degree (to size d' in FIG. 17) when
it is inserted into the reel urging spring insertion area 210, thus
assuring more positive engagement.
[0288] In the illustrated case, that part of the reel urging spring
220 which is to be inserted into the reel urging spring insertion
area 210 is designed to have two hairpin-like bends 222. However,
the shape of this part is by no means limiting and it may be
designed to have any shape that exhibits a specified degree of
spring elasticity when the reel urging spring 220 is inserted into
the reel urging spring insertion area 210.
[0289] FIG. 16A is a perspective view showing the whole exterior
appearance of the magnetic tape cassette according to the example
under consideration which is furnished with the reel urging spring
engage-and-stop mechanism of the design just described above, and
FIG. 16B shows enlarged the region around the reel urging spring
insertion area 210.
[0290] As shown in FIGS. 16A and 16B, the magnetic tape cassette
according to the example under consideration has the recess 211 in
the reel urging spring insertion area 210 exposed on the upper
surface.
[0291] The upper half has a portion 213 that overhangs the recess
211 and which is surrounded by a groove 216 facing the recess 212.
When pulled up, the portion 213 breaks and so does the reel urging
spring insertion area 210. In other words, the portion 213 is an
easy-to-break part that enables the reel urging spring 220 to be
taken out of the magnetic tape cassette without separating and
breaking down the upper and lower halves.
[0292] In the illustrated case, the easy-to-break part 213 is
surrounded by the groove 216 formed in only the obverse surface of
the upper half 200. This is not the sole case of the invention and
a groove may be formed in the reverse surface or in both the
obverse and reverse surfaces of the upper half 200. The groove need
not surround the entire perimeter of the easy-to-break part 213 or
it may be discontinuous rather than continuous. The easy-to-break
part 213 as surrounded by the groove 216 also has a capability for
preventing dust particles from getting into the cassette. The
reference numeral 202 designates the lower half and the reference
numeral 200a designates a transparent inspection window.
[0293] The magnetic tape cassette according to the example
described above has not only the advantage that by disassembling it
into the upper and lower halves, the reel urging spring 220 can be
taken out of the cassette without using any special tool and the
like; another advantage is that without disassembling the magnetic
tape cassette into the upper and lower halves but by using a
suitable jig, one can remove the reel urging spring 220 alone and
thereby contributes to facilitating the assorted collection of
constituent materials.
[0294] FIG. 19 shows in section a reel urging spring insertion area
of the magnetic tape cassette according to another example of the
ninth aspect of the invention. The difference from the example
shown in FIG. 17 lies in the shape of the reel urging spring 230.
As shown, the reel urging spring 230 according to the example under
consideration has not only a dual bend 232 that is inserted into
the recess 212 in the reel urging spring insertion area 210 to
contact the upper half 200 but also an additional bend 232a which
is oriented perpendicular to the bend 232 and placed in contact
with the inner surface of that area of the upper half 200 which
faces the recess 212, thereby protecting the reel urging spring
insertion area 210 (recess 212) more effectively against dust
coming from the outside. In addition, the reel urging spring 230
clamps a lug 214 formed in the lower part of the recess 211 in the
upper half 200 and this assures more positive engagement of the
reel urging spring 230. Needless to say, the reel urging spring 230
has an elastic portion 233 at the distal end of the bend 232 and a
flat portion 234 at the terminal end of the bend 232a.
[0295] FIG. 20 shows in section a reel urging spring insertion area
of the magnetic tape cassette according to yet another example of
the ninth aspect of the invention. The difference from the examples
shown in FIGS. 16 and 19 is that the shape of the reel urging
spring 240 is simpler. To be specific, the reel urging spring 240
according to the example under consideration has a very simple
shape in that the portion which is to be brought into engagement
with the recess 212 in the reel urging spring insertion area 210
has only two bends and this design facilitates the manufacture of
the reel urging spring. To be more specific, the reel urging spring
240 consists of an elastic portion 243, a hook (or crank) shaped
bend 242 that is continuous from the elastic portion 243 at an
acute angle and which then bends at right angles, and a flat
portion 244 continuous from the bend 242.
[0296] In the example under consideration, a recess 252 which comes
into engagement with a projection 245 on the reel urging spring 240
is provided in the reel urging spring insertion area 210 (i.e., on
the bottom of the recess 211 in the illustrated case) in order to
assure positive engagement of the reel urging spring 240. This
design is simple and yet has the advantage of bringing the reel
urging spring 240 into positive engagement with the reel urging
spring insertion area 210.
[0297] Again, the magnetic tape cassettes using the reel urging
spring engage-and-stop mechanisms according to the examples just
described above offer the advantage that there is no need to use
tools in order to take out the reel urging spring from the magnetic
tape cassette as it is torn apart; in addition, constituent
materials of the magnetic tape cassette can be efficiently assorted
according to their kind.
[0298] Described above are the basic features of the design for the
magnetic tape cassette according to the ninth aspect of the
invention.
[0299] We next describe a magnetic tape cassette according to the
tenth aspect of the invention with reference to FIGS. 21-30.
[0300] In the following description of the magnetic tape cassette
according to the tenth aspect of the invention, a two-reel type
magnetic tape cassette is taken as an example. The magnetic tape
cassette according to this example of the tenth aspect of the
invention has basically the same construction as the prior art
magnetic tape cassette shown in FIG. 53, except for the design of
the reel urging spring used as the reel retaining spring.
Therefore, the following description is directed to only the design
of the reel urging spring.
[0301] FIG. 21 is a perspective view showing an example of the reel
urging spring structure in the magnetic tape cassette according to
the tenth aspect of the invention as it has been mounted in a tape
reel; FIG. 22 is a perspective view showing enlarged the reel
urging structure of FIG. 21 as it has been mounted in the tape
reel; FIG. 23 is a perspective view showing spring seats as
elements of the reel urging structure shown in FIG. 22; FIG. 24 is
a perspective view showing the upper surface of a reel urging
spring as another element of the reel urging structure shown in
FIG. 22; FIG. 25 is a perspective view showing the lower surface of
the reel urging spring shown in FIG. 24; and FIG. 26 is a
perspective view showing how the recess in the reel urging spring
is associated with a pivot provided on the upper half.
[0302] As shown in FIGS. 21-26, the reel urging spring in the
magnetic tape cassette according to the example under consideration
is buried in the center of the upper flange 302 of the tape reel
300; a plurality of spring seats 304 are provided in a recessed
area in the center of the upper flange 302 and the reel urging
spring 306 in the form of a plurality of elastic arms 306a
extending radially from the central base (in the same plane) is
placed to rest on the spring seats 304. The plurality of elastic
arms 306a (six in the illustrated case) in the reel urging spring
306 are fitted into grooves 304a in the plurality of spring seats
304 (six in the illustrated case) and fixed in position; thus, the
reel urging spring 306 needs only to be placed on the spring seats
304 in order to be situated in the center of the upper flange 302
of the tape reel 300.
[0303] A spherical concavity 306b is provided in the central base
of the reel urging spring 306; a pivot 308 having a spherical
convex 308a formed at the tip with a smaller radius of curvature
than that of the concavity 306b is provided on the inner surface of
the upper half (not shown) in the position corresponding to the
center of the tape reel 300 and in such a way as to project
downward. As shown in FIG. 26, the convex 308a of the pivot 308
provided on the inner surface of the upper half is fitted into the
concavity 306b at the central base of the reel urging spring 306
and then depressed, whereupon the reel urging spring 306 is
depressed to cause a downward deformation of the elastic arms 306a;
the urging force developed by the deformed elastic arms 306a causes
the tape reel 300 to be depressed toward the lower half. The
above-described structural design of the reel urging spring
according to the example under consideration has the advantage that
even if the elastic arms 306a of the reel urging spring 306 are not
completely fixed at their distal ends, the reel urging spring 306
can always be situated at the center of the flange of the tape reel
300 by fitting the convex 308a of the pivot 308 into the concavity
306b.
[0304] The elastic arms 306a of the reel urging spring 306 may be
in the form of metallic leaf spring; however, considering the need
to disassemble the discarded magnetic tape cassette and collect the
respective components after assorting them according to material,
the elastic arms 306a are desirably made of nonmetallic highly
elastic materials such as rigid rubber and highly elastic plastics,
with highly elastic plastics being particularly desirable. The
elastic arms 306a suitably range from two to eight in number and,
in order to ensure that they can be placed in stable position while
preventing them from being cluttered, the elastic arms 306a are
desirably from three to six in number.
[0305] In order to ensure that the elastic arms 306a provide an
appropriate urging force, the reel urging spring 306 may have a
thin-walled portion 306c in the lower part of each elastic arm 306a
as shown in FIG. 25. The thin-walled portion 306c may be a
semicircular recess as shown in FIG. 25; alternatively, it may be
long enough to cover almost the entire length of each elastic arm
306a. While the thickness of each elastic arm 306a varies with the
constituent material or the required urging force, it is generally
desired to select a value of about 0.6 mm.
[0306] Of course, the relative positions of the pivot and the
concavity may be reversed so that the concavity is provided in the
inner surface of the upper half whereas the pivot is provided at
the central base of the reel urging spring 306. If desired, the
pivot may be made of plastic having a lower friction coefficient
than the reel urging spring 306 or the inner surface of the upper
half or, alternatively, the surface of the pivot may be coated with
a material of lower friction coefficient so that the drive force
required to rotate the tape reel 300 is sufficiently reduced to
permit smoother rotation of it.
[0307] FIG. 27 is a perspective view showing another example of the
design for the reel urging spring in the magnetic tape cassette
according to the tenth aspect of the invention as it has been
mounted in a tape reel. As shown, the tape reel 310 has a plurality
of slit-like spring seats 314 (four in the illustrated case) formed
in the surface of an upper flange 312 and the tips of a plurality
of elastic arms 316a (four in the illustrated case) that extend
radially from the central base of the reel urging spring 316 are
inserted into the respective slits such that the central base of
the reel urging spring 316 is situated at a higher position than
the tips of the respective elastic arms 316a. In the example under
consideration, a convex 316b provided at the central base of the
reel urging spring 316 is depressed by the inner surface of the
upper half (not shown) so that the elastic arms 316a deform
downward, whereupon an urging force develops to depress the tape
reel 310 toward the lower half.
[0308] The convex 316b at the central base of the reel urging
spring 316 is not necessarily an essential element; however,
smaller friction occurs if the reel urging spring 316 makes point
contact with the inner surface of the upper half in the position
where it is being depressed by the latter and, hence, the convex
316b is desirably provided at the central base of the reel urging
spring 316. On the other hand, there is no need to form a concavity
in the inner surface of the upper half because the elastic arms
316a, with their tips inserted into the slit-like spring seats 314,
are completely controlled in their position so that the central
position of the reel urging spring 316 automatically aligns with
the center of the tape reel 310. As for other design considerations
including the constituent material of the elastic arms 316a, the
number of the arms, the formation of thin-walled portions and the
use of a material of lower fiction coefficient, the comments given
in connection with the example shown in FIGS. 21-26 will apply and
there is no need to give detailed explanation here.
[0309] FIG. 28 is a perspective view showing in partial section a
third example of the design for the reel urging spring in the
magnetic tape cassette according to the tenth aspect of the
invention as it has been mounted in a tape reel. FIG. 29 is a
perspective view showing the reel urging spring mounting portion of
the tape reel, with the upper flange being removed. FIG. 30 is a
perspective view showing the shape of the reel urging spring shown.
As these figures show, the reel urging spring of the example under
consideration has such a structure that a circular center hole 322a
is provided in the center of an upper flange 322 of a tape reel 320
and that a plurality of spring seats 324 (four in the illustrated
case) into which the tips of a plurality of elastic arms 326a (four
in the illustrated case) that extend from the central base of the
reel urging spring 326 are to be inserted are formed beneath the
perimeter of the center hole 322a.
[0310] In the example under consideration, the tape reel 320 is
assembled with the reel urging spring 326 being mounted inside of
it in order to ensure that once inserted into the spring seats 324,
the reel urging spring 326 will not come off. To this end, the
spring seats 324 are formed on the upper surface of a hub 330 in a
tape reel substrate 328 (see FIG. 29) before the upper flange 322
is mounted; on these spring seats 324, the reel urging spring 326
whose central base is at a higher position than the tips of the
elastic arms (see FIG. 30) are placed and the upper flange 322 is
then placed on top of the reel urging spring 326 such that the
latter passes through the center hole 322a in the upper flange 322
and project therefrom.
[0311] In the example under consideration, no convex is provided at
the central base of the reel urging spring 326 but, if necessary, a
convex may be provided as mentioned above. Again, the center of the
reel urging spring 326 is depressed by the inner surface of the
upper half so that the elastic arms 326a deform downward, whereupon
an urging force develops to depress the tape reel 320 toward the
lower half. In the example under consideration, the tips of the
elastic arms 326a of the reel urging spring 326 are designed to be
capable of moving lengthwise through the spring seats 324, so on
account of the depressing force exerted by the inner surface of the
upper half, the elastic arms 326a slide through the spring seats
324 such that the reel urging spring 326 is depressed to a lower
position.
[0312] As for other design considerations including the constituent
material of the elastic arms 326a, the number of the arms, the
formation of thin-walled portions and the use of a material of
lower fiction coefficient, the comments given in connection with
the example shown in FIGS. 21-26 will also apply and there is no
need to give detailed explanation here. When disassembling the
discarded magnetic tape cassette and collecting the respective
components by assorting them by material, one needs only to pull up
the central base of the reel urging spring 326, whereupon it can be
easily dislodged from the tape reel 320 without causing undue
burden on the personnel who are working on the magnetic tape
cassette to break it down.
[0313] While the two examples in the foregoing description are
directed to a two-reel type magnetic tape cassette, the concept of
the invention is equally applicable to a one-reel type magnetic
tape cassette.
[0314] Described above are the basic features of the design for the
magnetic tape cassette according to the tenth aspect of the
invention.
[0315] A tape reel that can be broken down according to the third
aspect of the invention is now described with reference to FIGS.
31-34.
[0316] Note that the tape reel that can be broken down according to
the third aspect of the invention is applicable to both the
above-mentioned one-reel type magnetic tape and the conventional
two-reel type magnetic tape cassette illustrated in FIG. 53. Also
note that the constituent elements of the cassette other than the
tape reel according to the third aspect of the invention are not
limited in any particular way and may be the same as those used in
the prior art magnetic tape cassette shown in FIG. 53; hence, those
constituent elements are not shown specifically in FIGS. 31-34, nor
are they explained in the following description.
[0317] FIG. 31 is a perspective view showing in partial section the
overall shape of a tape reel that can be broken down according to
an example of the third aspect of the invention; FIGS. 32-34 are
perspective views showing an example each of the lower flange, the
upper flange and the reel urging (retaining) spring as components
of the tape reel shown.
[0318] As shown in FIG. 31, the tape reel 340 that can be broken
down according to the third aspect of the invention comprises a
lower flange 344 formed as an integral part of a reel hub 342
around which magnetic tape (not shown) is to be wound and an upper
flange 346 which is circular and formed as a generally flat plate.
The tape reel 340 is combined with a reel urging spring 348 that
contacts the inner surface of the upper half 12 to urge the tape
reel 340 toward the lower half 14.
[0319] The lower flange 344 formed as an integral part of the reel
hub 342 has three concentric cylindrical tubes 342a, 342b and 342c,
with a fixing end 342d (see FIG. 32) provided in part of the
outermost cylindrical tube 342a for fixing an end of magnetic
tape.
[0320] A multiple of ribs 342e are provided between the outermost
cylindrical tube 342a and the intermediate cylindrical tube 342b
which is connected to the innermost cylindrical tube 342c by an
intermediate wall 342f and the upper end of the innermost
cylindrical tube 342c is fitted with a cover 342g; this structural
design prevents deformation of the three concentric cylindrical
tubes 342a, 342b and 342c and guarantees adequate mechanical
strength.
[0321] A plurality of engage-and-stop lugs 342h (three in the
example under consideration) are formed on the circumference of the
innermost cylindrical tube 342c to extend outward. Engagement
grooves 342i are provided in the upper surface of the intermediate
cylindrical tube 342b at a position intermediate between adjacent
engage-and-stop lugs 342h.
[0322] As shown in FIG. 33, the upper flange 346 has a cylindrical
portion 346a that fits to the inside of the upper end of the
intermediate cylindrical tube 342b of the reel hub 342 and from
this cylindrical portion 346a, engage-and-stop pawls 346b project
downward in a number that corresponds to the number (three in the
example under consideration) of engage-and-stop lugs 342h on the
reel hub 342.
[0323] When the cylindrical portion 346a of the upper flange 346 is
inserted to a specified position inside the intermediate
cylindrical tube 342b of the reel hub 342, the engage-and-stop
pawls 346b of the upper flange 346 are brought into engagement with
the engage-and-stop lugs 342h of the reel hub 342. Provided at a
position intermediate between engage-and-stop pawls 346b of the
cylindrical portion 346a is an engagement groove 346c of the same
width as the engagement groove 342i in the reel hub 342.
[0324] The reel urging spring 348 functions as a reel retaining
spring; a leg 348a is inserted into the engagement groove 342i in
the upper surface of the intermediate cylindrical tube 342b of the
reel hub 342 and into the engagement groove 346c of same width in
the cylindrical portion 346a of the upper flange 346, whereupon the
tape reel according to the example under consideration is prevented
from lifting up toward the inner surface of the upper half; as
shown in FIG. 34, the reel urging spring 348 has three of such legs
348a that extend radially outward from the central base.
[0325] As just described above, the engage-and-stop pawls 346b of
the upper flange 346 are brought into engagement with the
engage-and-stop lugs 342h of the reel hub 342, whereby the upper
flange 346 forms an inseparable integral unit with the lower flange
344. At the same time, the legs 348a of the reel urging spring 348
are inserted into the engagement grooves 346c in the upper flange
346 and into the engagement grooves 342i in the upper end of the
reel hub 342, whereby the tape reel is prevented from lifting up
toward the inner surface of the tape reel. As a result of these
actions, the lower flange 344 and the upper flange 346 make a
positive integral unit and will not tear apart during service.
[0326] As is clear from FIG. 34, the legs 348a of the reel urging
spring 348 describe a generally conical shape such that a spherical
convex 348b at the central base will project from the upper surface
of the upper flange 346. Hence, when the lower half 454 is combined
with the upper half 452 to make the cassette case (see FIG. 53) and
the tape reel 340 is assembled into the case to fabricate the
magnetic tape cassette, the legs 348a and the convex 348b come into
contact with the inner surface of the upper half 452, acting
together as a spring that urges the tape reel 340 toward the lower
half 454.
[0327] When the magnetic tape cassette is discarded after use and
the respective parts are assorted by material, the following
procedure may simply be taken; the reel urging spring 348 is first
removed and then a screwdriver or the like is inserted into the
reel hub 342 from below and the engage-and-stop pawls 346b on the
upper flange 346 are disengaged from the engage-and-stop lugs 342h
on the reel hub 342, whereupon the magnetic tape cassette can be
easily broken down into respective parts. The magnetic tape
cassette can be broken down more easily if the tips of the
engage-and-stop lugs 342h are tapered as shown in FIG. 31 and
pushed outward by means of an inserted dedicated tool in a
cylindrical form.
[0328] The foregoing example is just one case of the invention and
should by no means be taken as limiting. Various improvements and
modifications can of course be made without departing from the
spirit and scope of the invention; for instance, the width and
thickness of the legs 348a of the reel urging spring 348 may be
modified or the number of the legs 348a may be changed so as to
modify the force by which the tape reel 340 is urged toward the
lower half 454.
[0329] Described above are the basic features of the design for the
magnetic tape cassette according to the third aspect of the
invention.
[0330] A tape reel that can be broken down according to the fourth
aspect of the invention will now be described with reference to
FIGS. 35-42.
[0331] Note that the tape reel that can be broken down according to
the fourth aspect of the invention is applicable to both the
above-mentioned one-reel type magnetic tape and the conventional
two-reel type magnetic tape cassette illustrated in FIG. 53. Also
note that the constituent elements of the cassette other than the
tape reel according to the fourth aspect of the invention are not
limited in any particular way and may be the same as those used in
the prior art magnetic tape cassette shown in FIG. 53; hence, those
constituent elements are not shown specifically in FIGS. 35-42, nor
are they explained in the following description.
[0332] FIG. 35 is a perspective view showing in partial section the
overall shape of a tape reel that can be broken down according to
an example of the fourth aspect of the invention; FIGS. 36-38 are
perspective views showing an example each of the lower flange, the
upper flange and the engage-and-stop member as components of the
tape reel shown. FIGS. 39-41 are perspective views showing in
partial section the essential part of the lower flange, the upper
flange and the engage-and-stop member as components of the tape
reel shown. FIG. 42 is a fragmentary perspective view showing the
essential part in which the lower flange, the upper flange and the
engage-and-stop member have been combined in the example under
consideration.
[0333] As shown in FIGS. 35 and 36, the tape reel 350 that can be
broken down according to the fourth aspect of the invention
comprises a lower flange 354 formed as an integral part of a reel
hub 352 around which magnetic tape (not shown) is to be wound, an
upper flange 346 which is circular and formed as a generally flat
plate, and an engage-and-stop member 358 that secures the lower
flange 354 and the upper flange 356 as an integral unit.
[0334] The lower flange 354 formed as an integral part of the reel
hub 352 has three concentric cylindrical tubes 352a, 352b and 352c,
with a fixing end 352d (see FIG. 36) provided in part of the
outermost cylindrical tube 352a for fixing an end of magnetic
tape.
[0335] A multiple of ribs 352e are provided between the outermost
cylindrical tube 352a and the intermediate cylindrical tube 352b
which is connected to the innermost cylindrical tube 352c by an
intermediate wall 352f, this structural design prevents deformation
of the three concentric cylindrical tubes 352a, 352b and 352c and
guarantees adequate mechanical strength.
[0336] A first group of engage-and-stop pawls 352g (three in FIG.
36) are formed at the upper end of the innermost cylindrical tube
352c to extend outward (see FIG. 39).
[0337] As shown in FIGS. 37 and 40, the upper flange 356 has a
cylindrical portion 356a that fits to the inside of the
intermediate cylindrical tube 352b of the reel hub 352 and from the
lower end of this cylindrical portion 356a, a second group of
engage-and-stop pawls 356b project inward in a number that
corresponds to the number (three in the illustrated example) of the
first group of engage-and-stop pawls 352g on the reel hub 352. When
the cylindrical portion 356a of the upper flange 356 is inserted
inside the intermediate cylindrical tube 352b of the reel hub 352
and twisted clockwise, the second group of engage-and-stop pawls
356b will be brought into engagement with the first group of
engage-and-stop pawls 352g; positioning of the second group of
engage-and-stop pawls 356b in the rotational direction is effected
by means of a stopper 356c (see FIG. 42).
[0338] As shown in FIGS. 38 and 41, the engage-and-stop member 358
is inserted between the intermediate cylindrical tube 352b of the
reel hub 352 and the innermost cylindrical tube 352c and has a
third group of engage-and-stop pawls 358a (three in the illustrated
example) that extend downward. After being inserted between the
intermediate cylindrical tube 352b of the reel hub 352 and the
innermost cylindrical tube 352c, the third group of engage-and-stop
pawls 358a are twisted counterclockwise to the position where the
first group of engage-and-stop pawls 352g are in engagement with
the second group of engage-and-stop pawls 356b, whereupon the
second engage-and-stop pawl 356b of the upper flange 356 is
securely held between the first engage-and-stop pawl 352g of the
reel hub 352 and the third engage-and-stop pawl 358a to prevent
further twisting of the upper flange 356 (see FIG. 42).
[0339] To be more specific, the upper flange 356 cannot be twisted
any further in a clockwise direction because the stopper 356c on
the second engage-and-stop pawl 356b contacts the first
engage-and-stop pawl 352g on the reel hub 352 (see FIG. 42); the
upper flange 356 cannot be twisted any further in a
counterclockwise direction because the second engage-and-stop pawl
356b is held between the first engage-and-stop pawl 352g and the
third engage-and-stop pawl 358a.
[0340] Any insufficiency in the holding power to be exerted by the
first engage-and-stop pawl 352g and the third engage-and-stop pawl
358a can be easily dealt with by forming tiny asperities in the
mating surfaces of the first engage-and-stop pawl 352g and the
second engage-and-stop pawl 356b or by making those mating surfaces
slightly tapered to provide large enough friction against the
twisting of the upper flange 356.
[0341] The engage-and-stop member 358 has a conical elastic portion
358b formed in the center and a spherical convex 358c is provided
at the center such that it will project from the upper surface of
the upper flange 356. When the lower half 454 is combined with the
upper half 452 to make the cassette case (see FIG. 53) and the tape
reel 350 is assembled into the case to fabricate the magnetic tape
cassette, the elastic portion 358b and the convex 358c come into
contact with the inner surface of the upper half 452, acting
together as a spring that urges the tape reel 350 toward the lower
half 454. Thus, in the example under consideration, the
engage-and-stop member 358 also functions as a reel retaining
spring.
[0342] The foregoing example is just one case of the invention and
should by no means be taken as limiting. For instance, the
engage-and-stop pawls 352g to be provided on the reel hub 352 may
be interchanged for the engage-and-stop pawls 356b (356c) provided
on the upper flange 356 and L-shaped engage-and-stop pawls may be
provided on the reel hub 352 rather than on the upper flange
356.
[0343] Various other improvements and modifications can of course
be made without departing from the spirit and scope of the
invention; for instance, slits may be provided as appropriate in
the elastic portion 358b of the engage-and-stop member 358 in order
to modify the force by which the tape reel 350 is urged toward the
lower half 454.
[0344] Described above are the basic features of the design for the
magnetic tape cassette according to the fourth aspect of the
invention.
[0345] A tape reel that can be broken down according to the fifth
aspect of the invention is now described with reference to FIGS.
43-45.
[0346] Note that the tape reel that can be broken down according to
the fifth aspect of the invention is applicable to both the
above-mentioned one-reel type magnetic tape and the conventional
two-reel type magnetic tape cassette illustrated in FIG. 53. Also
note that the constituent elements of the cassette other than the
tape reel according to the fifth aspect of the invention are not
limited in any particular way and may be the same as those used in
the prior art magnetic tape cassette shown in FIG. 53; hence, those
constituent elements are not shown specifically in FIGS. 43-45, nor
are they explained in the following description.
[0347] FIG. 43 is a cross-sectional view showing the essential part
(central part) of a specific example of the tape reel that can be
broken down according to the fifth aspect of the invention. As
shown in FIG. 43, the tape reel 360 that can be broken down
according to the fifth aspect of the invention comprises a lower
flange 364 formed as an integral part of a reel hub 362 around
which magnetic tape (not shown) is to be wound and an upper flange
366 which is circular and formed as a generally flat plate.
[0348] The reel hub 362 formed as an integral part of the lower
flange 364 consists of an outer tube 362a around which magnetic
tape (not shown) is to be wound and an inner tube 362c provided in
its interior with a coupling portion 362b into which the reel shaft
on the record/reproduce apparatus is to be inserted (the specific
shape of the coupling portion 362b is not shown); the outer tube
362a and the inner tube 362c are joined integrally by means of ribs
362d.
[0349] An engage-and-stop lug 368 is provided on the inner surface
of the outer tube 362a in such a way as to project inward whereas
an engage-and-stop lug 370 is provided on the outer surface of the
inner tube 362c in such a way as to project outward. The upper part
of the inner tube 362c is closed and a convex 362e is provided at
the center of the closed top such that the lower flange 364 will
contact the upper flange 366 via the convex 362e.
[0350] Provided in the center of the upper flange 366 is a space
366a reserved for the means of urging the tape reel 360 toward the
lower half; engage-and-stop pawls 372 and 374 extend downward from
below the space 366a. The engage-and-stop pawls 372 and 374 work as
engaging members that bring the upper flange 366 into contact and
engagement with the lower flange 364; the engage-and-stop pawl 372
is snap fitted to the engage-and-stop lug 368 whereas the
engage-and-stop pawl 374 is snap fitted to the engage-and-stop lug
370, thus causing the upper flange 366 to be secured to the lower
flange 364. In the example under consideration, three
engage-and-stop pawls 372 are provided as spaced apart by 120
degrees such that they come into contact and engagement with the
engage-and-stop lug 368 on the outer tube 362a and three
engage-and-stop pawls 374 are provided as spaced apart by 120
degrees such that they come into contact and engagement with the
engage-and-stop lug 370 on the inner tube 362c. It should be noted
here that the engage-and-stop pawls 372 and 374 are not both
required and either one of them will do.
[0351] To mount the upper flange 366 onto the lower flange 364, the
following procedure may be taken. First, the engage-and-stop pawls
372 are inserted and strongly depressed from above, whereupon the
convex 362e at the center of the upper part of the inner tube 362c
on the reel hub 362 made integral with the lower flange 364 deforms
elastically, causing the engage-and-stop pawls 372 and 374 to snap
fit to the engage-and-stop lugs 368 and 370 on the lower flange
364, whereby the upper flange 366 is mounted onto the lower flange
364. If the applied depressing force is removed after inserting the
engage-and-stop pawls 372, the elastically deformed convex 362e
causes the force that urges the upper flange 366 upward and this
urging force is strong enough to get the upper flange 366 to be
joined and secured tightly to the lower flange 364.
[0352] If the upper flange 366 is joined to the lower flange 364 in
the way just described above, the convex 362e at which the lower
flange 364 contacts the upper flange 366 is situated inward of the
engage-and-stop pawls 372 and 374 on the upper flange 366 but in a
position a reasonable distance away from the flange surface 376 of
the upper flange 366; the urging force developed by the elastically
deformed convex 362e acts in such a way as to urge the upper flange
366 upward.
[0353] As a consequence, the axial position of the upper flange 366
is determined by the distance from the reference plane A of the
lower flange 364 to the engage-and-stop lug 368 or 370 and by the
length from the reference plane B of the upper flange 366 to the
engage-and-stop pawl 372 or 374; hence, the position of the flange
surface 376 of the upper flange 366 can be accurately determined by
ensuring that the heights of the engage-and-stop lugs 368 and 370
and the lengths of the engage-and-stop pawls 372 and 374 have
accurate values.
[0354] In addition, as will be apparent from the foregoing
description, the convex 362e at which the lower flange 364 contacts
the upper flange 366 is desirably situated inward of the
engage-and-stop pawls 372 and 374 on the upper flange 366 but in a
position a reasonable distance away from the flange surface 376 of
the upper flange 366, namely, either at the center of the reel hub
362 or in a nearby area; most desirably, the convex 362e is
situated at the center of the reel hub 362 as illustrated in the
specific example above. The convex 362e serves as the means of
exerting an urging force on the engage-and-stop pawls 372 and 374
on the upper flange 366 that have been snap fitted to the
engage-and-stop lugs 368 and 370 on the lower flange 364 and it can
obviously be provided on the upper flange 366 rather than on the
lower flange 364.
[0355] FIG. 44 is a cross-sectional view showing the structure of
the essential part (central part) of a die assembly for molding the
reel hub 362 of the lower flange 364 in the specific example under
consideration. The die assembly generally indicated by 380 has
essentially the same structure as the ordinary type and comprises a
moving upper die 382 and a fixed lower die 384; into the space
defined by the upper die 382 and the lower die 384, molten plastic
is injected to mold a shape. The reference plane A of the lower
flange 364 is formed in the lower die 384 and planes C and D which
provide the engage-and-stop lugs 368 and 370 that are to be engaged
by the engage-and-stop pawls 372 and 374 are also formed in a fixed
core 386 secured integrally to the lower die 384.
[0356] Thus, the reference plane A of the lower flange 364 formed
in the lower die 384 and the planes C and D formed in the fixed
core 386 are provided parallel in the same orientation in either
the fixed die or the moving die (in the fixed die in the specific
example under consideration) and this assures high precision in
plastics processing. Even if the mating position of dies changes on
account of various factors including the precision in mating of
dies, its thermal deformation and the pressure of molten plastic
being injected, the relative positions of the reference plane A and
the planes C and D will not change and the precision in the molding
dies will be directly transferred to shaped parts.
[0357] The precision in the distance between the reference plane A
and the plane C or D can be adjusted to 0.01 mm without any
particular difficulty. Similarly, the distance from the reference
position B of the upper flange 366 to the engage-and-stop pawl 372
or 374 can be adjusted to 0.01 mm without any particular difficulty
since the they can be molded by a fixed die on the same side of the
die assembly; compared to the prior art, a ten times high precision
can be achieved with relative ease and the wobbling of the upper
flange 366 can be reduced drastically.
[0358] If the magnetic tape cassette using the tape reel that can
be broken down according to the example just described above is to
be discarded after service, a suitable tool is inserted into the
tape reel from below and the engage-and-stop pawls 372 and 374 are
disconnected from the engage-and-stop lugs 368 and 370, whereby the
upper flange 366 can be easily separated from the lower flange 364;
in this way, the respective parts of the magnetic tape cassette can
be assorted by material.
[0359] FIG. 45 is a cross-sectional view showing the essential part
(central part) of another specific example of the tape reel that
can be broken down according to the fifth aspect of the invention.
The example illustrated in FIG. 45 has the following differences
from the example shown in FIG. 43: the engage-and-stop lug 368 and
the engage-and-stop pawl 372 shown in FIG. 43 are omitted and only
the engage-and-stop lug 370 and the engage-and-stop pawl 374 are
used; the convex 362e as the area where the lower flange 364
contacts the upper flange 366 is replaced by a mesa-shaped
projection 388 that will not deform elastically and an elastically
deformable portion 390 is provided on the upper flange 366.
[0360] The other features of the design shown in FIG. 45 are
identical to those of the specific example shown in FIG. 43 and
need not be described here in detail. Needless to say, the design
features of the specific example shown in FIG. 43 may be combined
with those of the specific example shown in FIG. 45 so that an
elastically deformable urging means is provided on both the lower
flange 364 and the upper flange 366 to ensure that the upper flange
366 is urged upward by the interaction of the two urging means.
[0361] The tape reel that can be broken down according to the fifth
aspect of the invention is by no means limited to the foregoing
examples and it goes without saying that various improvements and
alterations are possible without departing from the scope and
spirit of the invention; for instance, various modifications are
possible for the elastically deformable urging means and the urging
force can be adjusted to various intensities.
[0362] Described above are the basic design features of the tape
reel that can be broken down according to the fifth aspect of the
invention.
[0363] We next describe the resinous (plastic) leaf spring
according to the sixth aspect of the invention and the process for
its production with reference to FIGS. 46-52.
[0364] Note that the resinous leaf spring according to the sixth
aspect of the invention is applicable to both the above-mentioned
one-reel type magnetic tape and the conventional two-reel type
magnetic tape cassette illustrated in FIG. 53. Also note that the
constituent elements of the cassette other than the resinous leaf
spring according to the sixth aspect of the invention are not
limited in any particular way and may be the same as those used in
the prior art magnetic tape cassette shown in FIG. 53; hence, those
constituent elements are not shown specifically in FIGS. 46-52, nor
are they explained in the following description.
[0365] FIG. 46 is a perspective view showing the shape of a reel
urging spring in the form of a resinous (plastic) leaf spring
according to an example of the sixth aspect of the invention and
FIG. 47 is a cross-sectional view showing an exemplary die assembly
that may be used to mold the reel urging spring shown in FIG.
46.
[0366] The reel urging spring in the form of a resinous leaf spring
which is generally indicated by 400 in FIG. 46 functions as a reel
retaining spring and can be substituted for the conventional reel
retaining spring 466 in the form of a metallic leaf spring which is
shown in FIG. 53. As in the case of the conventional reel retaining
spring 466, the leaf spring 400 shown in FIG. 46 is turned upside
down before it is mounted on the upper half. To be more specific,
both end portions 400a of the leaf spring 400 are bent down and
with the aid of through-holes 400c in the center portion 400b, the
leaf spring 400 is fixed to the lower side of the bottom plate 452a
of the upper half 452, typically by ultrasonic or thermal welding
as in the case of the prior art. Mounted in this way, the reel
urging spring 400 depresses the centers of two tape reels 456 by
the end portions 400a so that they are urged toward the lower half
454.
[0367] The top (i.e., center 400b) of the mesa-shaped reel urging
spring 400 in the form of a resinous leaf spring is defined by two
inflection points 400d and the legs (i.e., end portions 400a) are
defined by two inflection points 400e. In the example under
consideration, thin-walled portions 400f are formed in the upper
part of areas near the inflection points 400d and thin-walled
portions 400g are also formed in the upper part of areas near the
inflection points 400e. The thin-walled portions 400f and 400g of
the leaf spring 400 having the shape shown in FIG. 46 contribute to
reducing the rigidity of the leaf spring 400. Without question, the
spring load of the leaf spring is in effect determined by the
rigidity of the thin-walled portions and, therefore, the spring
load of the leaf spring taken as a whole can be controlled by
adjusting the thickness of the thin-walled portions.
[0368] The mesa-shaped resinous leaf spring 400 having the
thin-walled portions 400f and 400g can be molded with a die
assembly of the design illustrated in FIG. 47, which is a
cross-sectional view showing an exemplary die assembly that may be
used to mold the reel urging spring 400 shown in FIG. 46. The die
assembly generally indicated by 402 in FIG. 47 has an upper die 404
and a lower die 406 as the base parts that define the basic shape
of the reel urging spring 400. In the example under consideration,
a moving part (movable core) 408 that can control the spring load
by adjusting the thickness of the reel urging spring 400 is
provided in the lower die (core) 406 under the inflection points
400d defining the top (i.e., center 400b) of the mesa-shaped reel
urging spring 400 and under the inflection points 400e defining the
legs (i.e., end portions 400a). The die assembly is so designed
that the moving cores 408 are moved up and down during molding in
order to control the thickness of the thin-walled portions 400f and
400g.
[0369] As indicated by two-head arrows in FIG. 47, the movable
cores 408 are capable of vertical movement and can be fixed at any
position. If the movable cores 408 are pushed up, the thicknesses
of the thin-walled portions 400f and 400g provided under the
inflection points 400d and 400e of the reel urging spring 400
decrease and so does the rigidity of the thin-walled portions to
reduce the spring load of the leaf spring taken as a whole; if the
movable cores 408 are pulled down, the thicknesses of the
thin-walled portions 400f and 400g provided under the inflection
points 400d and 400e of the reel urging spring 400 increase and so
does the rigidity of the thin-walled portions to increase the
spring load of the leaf spring taken as a whole. Hence, the die
assembly 402 has the advantage that it can mold the reel urging
spring 410 at various values of spring load by simply changing the
position of the movable cores 408.
[0370] FIG. 48 is a perspective view showing the shape of a reel
urging spring in the form of a resinous leaf spring according to
another example of the sixth aspect of the invention. As in the
case of the reel urging spring 400 shown in FIG. 46, the reel
urging spring generally indicated by 412 in FIG. 48 is turned
upside down before it is mounted on the upper half. To be more
specific, both end portions 412a of the reel urging spring 412 are
bent down and with the aid of through-holes 412c in the center
portion 412b, the reel urging spring 412 is fixed to the lower side
of the bottom plate 452a of the upper half 452, typically by
ultrasonic or thermal welding. As with the reel urging spring 400
shown in FIG. 46, the reel urging spring 412 depresses the centers
of two tape reels 456 by the end portions 412a so that they are
urged toward the lower half 454.
[0371] The reel urging spring 412 of the example under
consideration and the reel urging spring 400 shown in FIG. 46
differ in the following point: the reel urging spring 400 depends
on the thin-walled portions 400f and 400g for controlling spring
load but in the reel urging spring 412 according to the example
under consideration, recesses 412f and 412g are formed near
inflection points 412d and 412e and the sizes or depths of these
recesses 412f and 412g or their positions are changed to control
spring load.
[0372] The reel urging spring 412 described above can be molded
with a die assembly of the design illustrated in FIG. 49, which is
a cross-sectional view showing an exemplary die assembly that may
be used to mold the reel urging spring 412 shown in FIG. 48. The
die assembly generally indicated by 414 in FIG. 49 has an upper die
416 and a lower die 418 as the base parts that define the basic
shape of the reel urging spring 412. Moving pins 420 and 422 that
can control the spring load of the reel urging spring 412 are
provided on the upper die 416 near the inflection points 412d which
define the top (i.e., center 412b) of the mesa-shaped reel urging
spring 412 and on the lower die 418 near the inflection points 412e
which define the legs (i.e., end portions 412a).
[0373] By moving the pins 420 and 422 up and down, the sizes of the
recesses 412f and 412g (the depths of their dimples) relative to
the thickness of the leaf spring can be adjusted; at the same time,
by moving the pins 420 and 422 back and forth in a direction normal
to the paper, the depths of the recesses 412f and 412g in the
direction of the width of the leaf spring (how far the recesses
extend widthwise) can be adjusted.
[0374] The pins 420 and 422 are not only movable in the vertical
direction. They are also depressed by means of adjusting blocks 424
and 426; if the adjusting blocks 424 and 426 are moved to the right
and left as indicated by arrows in FIG. 49, the adjusting pins 420
and 422 are moved up and down and can be fixed at a desired
position, thereby adjusting the sizes (dimple depths) of the
recesses 412f and 412g which are provided in the reel urging spring
412 near the inflection points 412d and 412e. In addition, by
moving the pins 420 and 422 back and forth in a direction normal to
the paper, the depths of the recesses 412f and 412g in the
direction of the width of the leaf spring can be adjusted.
[0375] As in the example illustrated in FIG. 46, the reel urging
spring 412 according to the example under consideration allows
spring load adjustment by increasing the sizes of the recesses 412f
and 412g (the depths of their dimples) or the depths of the
recesses 412f and 412g, whereupon the rigidity of the reel urging
spring 412 at the recesses decreases to reduce the spring load of
the leaf spring or, alternatively, by reducing the sizes of the
recesses 412f and 412g (the depths of their dimples) or the depths
of the recesses 412f and 412g, whereupon the rigidity of the reel
urging spring 412 increases to increase the spring load of the leaf
spring. Hence, the die assembly 414 has the advantage that it can
mold the reel urging spring 426 at various values of spring load by
simply moving the pins 420 and 422 either vertically or in a
direction perpendicular to the paper.
[0376] If desired, the pins 420 and 422 may be moved to the right
and left (this case however is not shown in FIG. 49), whereupon the
positions of the recesses to be formed in the leaf spring are
changed so that the length of the leaf spring is effectively
changed to adjust its spring load. If the pins 420 and 422 are
positioned within the thicker portion of the leaf spring 428 as
illustrated in FIG. 50, holes 428a can be opened into a lateral
side of the leaf spring 428. In this alternative case, the spring
load of the leaf spring 428 can be adjusted by changing the depth
and position of the holes 428a made in a lateral side of the leaf
spring 428. If the holes 428a are through-holes, the spring load of
the leaf spring can be adjusted by effectively changing its length
or thickness.
[0377] FIGS. 51 and 52 are perspective views showing still other
examples of the sixth aspect of the invention.
[0378] The resinous leaf spring generally indicated by 430 in FIG.
51 is not intended for use in any particular application and it has
the mesa shape commonly adopted by resinous leaf springs. The leaf
spring 430 has cutouts 430a and 430b formed on opposite sides near
inflection points that define the mesa shape and the spring load of
the leaf spring 430 is adjusted by changing the depths of the
cutouts 430a and 430b. The depths of the cutouts 430a and 430b to
be formed in the leaf spring 430 can be easily controlled by
changing the position of the moving core in the direction of width
of the leaf spring 430.
[0379] The resinous leaf spring generally indicated by 432 in FIG.
52 has a plurality of legs 432a that extend radially from the
central base in a plurality of directions (three in the illustrated
case); the legs 432a have cutouts 432b that are similar to the
cutouts 430a and 430b in the leaf spring 430 illustrated in FIG. 51
and which are formed only in the neighborhood of inflection points
at the upper end of the leaf spring 432. In this case, too, the
spring load can be adjusted by changing the depth of the cutouts
432b. The depth of the cutouts 432b can also be changed easily by
varying the positions of pins in the direction of the width of the
leaf spring. A convex 432c that contacts the inner surface of the
upper half is provided at the central base of the leaf spring
432.
[0380] The resinous leaf springs 430 and 432 shown in FIGS. 51 and
52 are similar to the reel urging springs 400 and 412 in the form
of a resinous leaf spring in that they function as reel retaining
springs.
[0381] The die assembly used to mold the resinous leaf spring
according to the sixth aspect of the invention is in no way limited
to the foregoing examples and various other methods may be adopted.
Modified methods of forming thin-walled portions include forming
thin-walled portions each comprising a plurality of steps on the
leaf spring using a plurality of moving cores, as well as providing
a moving core in the direction of spring width in order to mold a
leaf spring that is reduced in width over a specified length rather
than forming recesses or cutouts in selected areas as shown in
FIGS. 50-52.
[0382] Modified methods can also be employed to form recesses or
cutouts. In one modification, through-holes sufficiently smaller
than the thickness of a leaf spring are provided through the
thickness of the leaf spring and moved in the direction of its
thickness so as to change the thicknesses of portions both above
and under the through-holes; in another modification, through-holes
are provided in a direction perpendicular to the thickness of a
leaf spring and the positions of the holes are changed along the
length of the leaf spring in order to vary its effective length. In
the foregoing examples, thin-walled portions and recesses or
cutouts are provided in the neighborhood of inflection points but
this is not the sole case of the invention and thin-walled portions
and recesses or cutouts may be situated at any position in the area
that works as a spring.
[0383] Described above are the basic design features of the
resinous leaf spring according to the sixth aspect of the invention
and the process for producing it.
[0384] While the magnetic tape cassette according to the invention,
the tape reel for use with it, as well as the resinous leaf spring
according to the invention and the process for producing it have
been described above in detail with reference to examples, it
should be understood that the invention is by no means limited to
the specific examples given and such examples can obviously be
adopted in any desired combinations. In addition, there is no need
to say that various improvements and alterations can be made
without departing from the spirit and scope of the invention.
[0385] As described above in detail, according to the first aspect
of the invention, tape reels housed in a cassette case can be urged
toward the lower half by means of a member whose structure is
simple and permits easy fitting and removal. For this reason, the
magnetic tape cassette according to the first aspect of the
invention is advantageous for assorted collection of resin
materials.
[0386] As described above, according to the second aspect of the
invention, a leaf-like reel urging spring can be easily removed
from the cassette case and even a metallic reel urging spring can
be easily separated for collection. For this reason, the magnetic
tape cassette according to the second aspect of the invention is
effective for the purpose of separating its constituent materials
into resin and metal and collecting them by material.
[0387] As described above in detail, according to the third, fourth
and fifth aspects of the invention, tape reels as parts of a
magnetic tape cassette discarded after use can be easily separated
and assorted by material.
[0388] To be specific, according to the third aspect of the
invention, there are provided tape reels that will not accidentally
tear apart during service of a magnetic tape cassette.
[0389] According to the fourth aspect of the invention, there are
provided tape reels that are protected against accidental tearing
apart during service of a magnetic tape cassette by preventing the
unwanted twisting of the upper flange.
[0390] According to the fifth aspect of the invention, there are
provided tape reels that can be broken down and which are so
designed that the upper flange wobbles to the smallest possible
extent.
[0391] As described above in detail, according to the sixth aspect
of the invention, thin-walled portions or recesses or cutouts are
formed in a resinous leaf spring, typically in the neighborhood of
inflection points; hence, by using a die assembly that can change
the thickness of thin-walled portions or the size or depth of
recesses or cutouts or their positions, one can easily adjust
spring load while molding the spring. Hence, the manufacturer who
is attempting to determine the appropriate spring load by trial
molding has no need to make a lot of expensive die assemblies and
he can produce many samples of leaf spring at low cost that have
different spring loads.
[0392] The die assembly used to mold the leaf spring comprises the
base part which defines the basic shape of the leaf spring and a
moving part that is capable of movement relative to said base part,
either said base part or said moving part being equipped with a
movable part that allows adjustment of the spring load of the leaf
spring and which is actuated to change the thickness of the leaf
spring or form recesses or cutouts in selected areas of the leaf
spring at varied sizes, depths or positions, thereby adjusting the
spring load of the leaf spring being molded. This offers the
advantage of enabling the manufacturer to prepare die assemblies
with ease on the basis of the conventional mold fabrication
technology.
[0393] Further, as described above, according to the seventh aspect
of the invention, tape reels housed in a cassette case can be urged
by means of a resinous member of a simple structure and they still
can be easily separated for collection by material.
[0394] As described above, according to the eighth aspect of the
invention, tape reels housed in a cassette case can be urged by
means of a simple and straightforward structure without using
metallic springs and this proves advantageous for assorted
collection of resin materials.
[0395] In addition, as described above in detail, according to the
ninth aspect of the invention, a reel urging spring the insertion
portion of which has at least two bends is inserted into a reel
urging spring insertion area provided in the upper half of a
magnetic tape cassette (recording media cartridge), whereby the
reel urging spring is brought into engagement with the upper half.
This offers the marked advantage of realizing a magnetic tape
cassette from which the reel urging spring can be easily taken
out.
[0396] Further in addition, as described above, according to the
tenth aspect of the invention, the metallic leaf spring
conventionally used as a reel urging spring in magnetic tape
cassettes is replaced by a nonmetallic spring which is mounted on
the tape reel, not as in the prior art being fixed to the inner
surface of the upper half by screwing, ultrasonic or thermal
welding, and the spring not only has an unconventional unique shape
but it can also be assembled into the cassette by simply being
placed in position. As a result, the need to perform screwing,
ultrasonic or thermal welding or otherwise secure the reel urging
spring is eliminated to enable the manufacture of magnetic tape
cassettes at even lower cost.
[0397] Another advantage that is offered is evident when a magnetic
tape cassette discarded after use is broken down into respective
parts which are assorted by material, collected and recycled at an
existing plant. To begin with, there are no metal parts that need
manual separation and, secondly, the reel urging spring can be
easily separated by simply breaking down the cassette or pulling up
the central part of the reel urging spring after the cassette is
torn apart; this contributes to substantial cut on the recycling
cost.
* * * * *