U.S. patent application number 11/447781 was filed with the patent office on 2007-01-04 for ribbon hub and spool assembly.
Invention is credited to Dennis R. White.
Application Number | 20070003351 11/447781 |
Document ID | / |
Family ID | 37025081 |
Filed Date | 2007-01-04 |
United States Patent
Application |
20070003351 |
Kind Code |
A1 |
White; Dennis R. |
January 4, 2007 |
Ribbon hub and spool assembly
Abstract
A ribbon hub and spool assembly includes a hub having at least
two cantilever beams having a smooth, tapered, and curved crown,
and a spool having curved and tapered splines. The cantilever beams
balance the forces when inserting the hub into the spool, and the
shape of the crowns of the hub and splines of the spool enable easy
insertion and alignment of the hub and spool assembly.
Inventors: |
White; Dennis R.; (Yorba
Linda, CA) |
Correspondence
Address: |
MACPHERSON KWOK CHEN & HEID LLP
2033 GATEWAY PLACE
SUITE 400
SAN JOSE
CA
95110
US
|
Family ID: |
37025081 |
Appl. No.: |
11/447781 |
Filed: |
June 6, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60692197 |
Jun 17, 2005 |
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Current U.S.
Class: |
400/242 |
Current CPC
Class: |
B41J 35/28 20130101;
B41J 33/00 20130101 |
Class at
Publication: |
400/242 |
International
Class: |
B65H 75/00 20060101
B65H075/00 |
Claims
1. A ribbon hub and spool assembly, comprising: a hub, comprising:
a cylindrical body having at least two recessed portions; at least
two flexible beams, each beam having a first end attached to a
bottom portion of the cylindrical body and a second end attached to
a curved and tapered crown, wherein the beams are radially movable
within the recessed portions; and a top portion; and a ribbon
spool, comprising: opposing flat discs; a cylindrical ring
connecting the two flat discs, wherein the cylindrical ring has an
inner surface and an outer surface; and a plurality of splines
along the inner surface of the ring, wherein the splines have at
least one curved and tapered end.
2. The assembly of claim 1, wherein the hub further comprises a
plurality of splines having curved ends extending toward the top
portion.
3. The assembly of claim 1, wherein the crown has a narrow tip
tapering laterally and radially outward, a guide portion having a
width corresponding to a portion between the splines of the spool,
and a center ridge extending from the narrow tip to the guide
portion.
4. The assembly of claim 1, wherein at least one of the beams has a
guide portion below the crown and extending outward, wherein the
guide portion has a width corresponding to a portion between the
splines of the spool.
5. The assembly of claim 1, wherein the hub further comprises a
bottom portion have a ledge with a larger circumference than the
cylindrical body.
6. The assembly of claim 1, wherein the spool further comprises an
angled annular surface connecting the cylindrical ring with the
flat disc.
7. The assembly of claim 1, wherein the flexible beams oppose each
other.
8. The assembly of claim 1, wherein the top portion has a
circumference smaller than the cylindrical body and an angled
surface tapering toward the outer circumference of the cylindrical
body.
9. A hub and spool assembly for a ribbon printing system,
comprising: a hub having at least one spline with a curved end, at
least two movable beams parallel to the spline, and a smoothly
curved and tapered crown at the end of each beam; and a spool
having a plurality of curved and tapered splines along an interior
portion of the spool, wherein the spline and crowns of the hub fit
between the splines of the spool during an assembly of the hub and
spool and when the hub and spool are fully assembled.
10. The assembly of claim 9, wherein the spool further comprises an
angled annular surface between the curved and tapered portion of
the splines and one of two planar surfaces of the spool.
11. The assembly of claim 9, wherein the hub further comprises an
annular surface angled inward from the curved end of the spline to
a top surface of the hub.
12. The assembly of claim 9, wherein at least one of the beams
comprises a guide portion extending outward from the beam.
13. The assembly of claim 9, wherein at least one of the crowns
comprises a guide portion extending from a bottom portion of the
crown.
14. The assembly of claim 9, wherein the hub further comprises a
bottom ledge extending beyond the at least one spline.
15. The assembly of claim 9, wherein the beams are connected to a
bottom portion of the hub.
16. The assembly of claim 9, wherein the crowns extend above a top
surface of the hub.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present invention claims priority to U.S. Provisional
Application Ser. No. 60/692,197, filed Jun. 17, 2005, and which is
incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Field of Invention
[0003] The present invention relates to a printer ink ribbon spool
and hub assembly.
[0004] 2. Related Art
[0005] Impact printers incorporate inked ribbon to supply ink for
the printing process. Typically this inked ribbon is provided as a
long length of fabric wound-up onto a supply spool, or it is stored
inside a cartridge in one long continuous loop. During the printing
process, the inked ribbon, whether on spools or in a cartridge, is
pulled through the printing station by means of one or more
motor-driven hubs that engage splines in the spools or
cartridge.
[0006] The ribbon system, including the inked fabric and its
associated cartridge or set of spools, is a consumable product that
must be periodically replaced. Replacement of the ribbon involves
lifting the cartridge or spools from motor driven hubs, and
re-installing a new cartridge or spools onto those hubs.
[0007] FIGS. 1 to 5 show a conventional spool and hub assembly 10.
Assembly 10 includes a spool 12 (FIGS. 3 and 4) and a hub 14 (FIGS.
1 and 2). As shown in FIG. 1, hub 14, which is typically
motor-driven, has one or more axially oriented splines 16. Splines
16 engage similar splines 18 within spool 12 (as shown in FIG. 3)
or drive rollers within the cartridge, i.e., splines 16 of hub 14
fit in the groove between splines 18 of spool 12. Hub 14 also has a
snap feature that prevents the spools or cartridge from moving
axially on the hubs. In this way the vertical alignment of the
ribbon with respect to the printing station is assured. In the
reciprocating spool design, this alignment is crucial.
[0008] There are a few aspects of the ribbon removal and
replacement procedure that are problematic for the user, to which
this invention is addressed. In the present art, most or all ribbon
drive hubs contain a single, cantilever beam type 20 of locking
feature. This beam must be deflected towards the central axis of
the hub (or pushed inward) in order to remove or install a ribbon.
The deflection force is typically applied by pushing against beam
20 with the spool as it is being installed, or by deflecting beam
20 with the thumb while lifting the spool away from the hub.
Because it is a single beam, the force required to deflect the beam
is not counter-balanced with an opposing force, making the
procedure awkward and difficult. FIG. 5 shows spool 12 and hub 14
assembled and locked. As seen, to remove hub 14 from spool 12, the
user has to depress beam 20, while also pushing hub 14 and spool 12
away from each other.
[0009] Installment of a new spool or cartridge is also complicated
by the need to visually or tactilely align spool splines 18 between
hub splines 16. This alignment involves rotating the spool or drive
roller so that the splines properly interleave. In a cartridge
application, because the internal splines within the cartridge
cannot be accessed or seen, this alignment can be very difficult if
the deflection of a cantilever snap feature is involved.
[0010] Therefore, there is a need for a printer ribbon spool and
hub assembly that overcomes the disadvantages discussed above.
SUMMARY
[0011] According to one aspect of the present invention, a hub and
spool assembly includes a hub having two or more tapered cantilever
beam snaps, a tapered top portion, and rounded splines along the
circumference of the hub, and a spool having a plurality of rounded
and tapered splines along a tapered interior of the spool. Such a
hub and spool assembly provides numerous advantages over
conventional assemblies.
[0012] The plurality of cantilever beam snaps enables opposing
forces to balance the loads when the beams are deflected during
spool or cassette installation. A tapered, rounded, or smoothly
blended crown or ridge on the top of the cantilever beam snaps lets
the user more easily begin insertion of the hub into the hole of
the spool. This also, in conjunction with the rounded splines of
the hub and the rounded, tapered splines of the spool allows for
self-alignment, resulting in an easier alignment of spool and hub.
The tapered edge along the opening of the spool enables easy
insertion of the hub. In addition, once "locked", the geometry of
the beam snaps and tapered edge allows the hub to be removed by
simply pushing out the hub, thereby eliminating the need to
directly depress the beam snaps.
[0013] In another embodiment, the crown of the beam snaps have a
tapered lower portion so that the spool does not need to have a
tapered edge along the opening. The tapered lower portion would
rest against the spool when the hub and spool are "locked". The
tapered lower portion would then similarly allow the user to remove
the hub by simply pushing out the hub, since the physical action of
pushing out the hub causes the cantilever to depress for easy
removal.
[0014] Embodiments of the present invention and their advantages
are best understood by referring to the detailed description that
follows.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1 is a perspective view of a conventional motor-driven
hub;
[0016] FIG. 2 is a top view of the hub of FIG. 1;
[0017] FIG. 3 is an enlarged view of the hole of a conventional
ribbon spool showing splines located therein;
[0018] FIG. 4 shows the hub of FIG. 1 being inserted into the spool
of FIG. 3;
[0019] FIG. 5 shows the hub of FIG. 1 fully inserted into the spool
of FIG. 3;
[0020] FIG. 6 is a side view of a motor-driven hub according to one
embodiment of the present invention;
[0021] FIG. 7 is a perspective view of the hub of FIG. 6;
[0022] FIG. 8 is a top view of the hub of FIG. 6;
[0023] FIG. 9 is an enlarged view of the splines along the interior
of a spool according to one embodiment of the present invention;
and
[0024] FIG. 10 shows the hub of FIG. 6 being inserted into the
spool of FIG. 9.
[0025] It should be appreciated that like reference numerals are
used to identify like elements illustrated in one or more of the
figures.
DETAILED DESCRIPTION
[0026] According to one embodiment of the present invention, a hub
and spool assembly for a printer system includes a hub with at
least two tapered cantilever beams, rounded splines, and a tapered
top, and a spool having rounded and tapered splines and a tapered
opening.
[0027] FIG. 6 is a side view of a hub 100 according to one
embodiment of the invention. FIG. 7 is a perspective view of hub
100, and FIG. 8 is a top view of hub 100. Hub 100 can be a
motor-driven hub for use in an impact printer system. In this
embodiment, hub 100 has a top flat surface 102 with an angled or
tapered portion 104 extending to the outer circumference of the
hub. A plurality of splines 106 is located along the outer
circumference of the hub, where splines 106 extend parallel to the
axis of rotation. Each spline 106 has a rounded or curved top
portion 108 at or near angled portion 104.
[0028] Hub 100 also has two opposing cantilever beams 110. Other
embodiments can have more than two such beams. Beams 110 are
attached to the base or a bottom portion of hub 100. The bottom
portion of hub 100 has a ledge 111 with a larger circumference than
the body of the hub. Hub 100 has recessed portions corresponding to
beams 110 so that an upper portion of beams 110 can be flexibly
pushed into the center of hub 100. In other words, when no force is
applied to beams 110, there is a gap in the recessed portion
between the center of the hub and the beams. Both hub 100 and beams
110 can be made by molding plastic or other suitable material. The
opposing beams enable forces to be balanced when inserting the hub
into a corresponding spool, where insertion pushes the beams toward
the center of the hub.
[0029] Cantilever beams 110 have a top portion or crown 112
extending above top surface 102 of hub 100. Crown 112 has a tapered
point 114 and a curved outer surface. Tapered point 114 extends
down a center ridge to flattened portion 116 having a width a
little less than the width between splines of the spool, as will be
discussed below. Tapered point 114 enables easy alignment with the
spool. The curved outer surface, center ridge, and angled portion
104 enable easy and smooth insertion into the spool. Flattened
portion 116 enables secure alignment with the spool. In one
embodiment, one of the cantilever beams has a guide portion 118
having a width approximately the same as the width of flattened
portion 116, i.e., a little less than the width between splines of
the spool, extending along a central portion of the beam. Guide
portion 118 extends to approximately the same plane as flattened
portion 116. This additional guide portion 118 engages with the
groove between splines of the spool for easy insertion and stable
alignment.
[0030] FIG. 9 shows an interior portion of a spool 200 according to
one embodiment of the present invention. Spool 200 has a hole which
hub 100 fits through. A plurality of splines 202 is located along
the interior portion or hole of spool 200. In one embodiment, spool
200 has a small beveled or tapered ring 204, where the taper
extends from the surface of the spool into the hole. Tapered ring
204 is present on both sides of spool 200. Splines 202 have curved
tapered ends 206 at both ends extending to the edge of tapered ring
204. In other words, the ends of the splines are sloped downward
toward the tapered ring. The combination of the tapered ring and
curved tapered ends of the splines enables easy insertion and
alignment of the hub.
[0031] FIG. 10 is a top view showing hub 100 being inserted into
spool 200. In operation, hub 100 is first pushed into the opening
of spool 200. Initially, the tapered point of the crowns contacts
the interior surface of the spool. The tapered ring of the spool
and the curved and tapered crown allows the user to easily insert
the hub into the spool. The two opposing cantilever beams are then
forced together as the hub is continually inserted into the spool.
The force from the cantilever beams are balanced so that the user
simply needs to push the hub into the spool to engage the beams
against the spool. This is in contrast to hubs having only one
cantilever beam, which can make both initial and continued
insertion difficult.
[0032] As the hub is continually pushed into the spool, the hub
quickly self-aligns with the splines of the spool. The curved and
tapered crowns and center ridge position themselves into the
grooves between splines of the spool. Continued insertion slides
the splines of the hub and the flattened portion and guide portion
of the cantilever beams along the grooves between the splines of
the spool. When the bottom ledge of the hub contacts the spool, the
hub is completed inserted into the spool. The crown of the
cantilever beams are then released from the inner portion of the
spool and expand over the surface of the spool.
[0033] When removing the hub from the spool, the user simply pushes
the hub back out. The opposing cantilever beams balance the force
for an easier movement. The tapered ring on the spool engages and
pushes inward the crown of the cantilever beams, thereby
eliminating the need for the user to directly push together the
crowns for hub removal. In other embodiments, the bottom of the
crowns may be tapered upward, with the spool having no tapered
ring. This would also enable the user to push out the hub without
directly pushing in the crowns.
[0034] Having thus described embodiments of the present invention,
persons skilled in the art will recognize that changes may be made
in form and detail without departing from the scope of the
invention. For example, the figures show numerous features for both
the hub and spool. However, not all are required to achieve
advantages over conventional hub and spool assemblies. Further, the
figures show two cantilever beams directly opposing each other.
Embodiments with more than two beams are also suitable, with each
beam spaced equally in angle from each other so that forces are
balanced. For example, if three beams are used, each beam would be
120.degree. apart. Thus the invention is limited only by the
following claims.
* * * * *