U.S. patent number 3,791,624 [Application Number 05/329,458] was granted by the patent office on 1974-02-12 for extendible tube assembly.
This patent grant is currently assigned to Roberts Consolidated Industries, Inc.. Invention is credited to Buford L. Payson.
United States Patent |
3,791,624 |
Payson |
February 12, 1974 |
EXTENDIBLE TUBE ASSEMBLY
Abstract
An extendible and locking assembly of telescoping tubular
members is described which can be secured in a carpet stretcher
system to provide a unique and highly efficient action in use of
the stretcher. The assembly comprises a pair of telescoping tubes,
one of which bears a lock tube and the other bears a sliding lock
that fits about the tube and prevents retraction of the members.
Manual release means are provided on the sliding lock to permit its
release when the members are to be retracted. When used in a carpet
stretcher assembly a unique "pump and pull" action results in which
the stretcher head or the tubes can be extended simply by
depressing and reaising the handle of the stretcher. This avoids
the conventional and tedious shifting and relocating of the
stretcher head. The assembly is preferably used in combination with
a ratchet lock power stretcher.
Inventors: |
Payson; Buford L. (Garden
Grove, CA) |
Assignee: |
Roberts Consolidated Industries,
Inc. (City of Industry, CA)
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Family
ID: |
23285493 |
Appl.
No.: |
05/329,458 |
Filed: |
February 5, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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186085 |
Oct 4, 1971 |
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Current U.S.
Class: |
254/212; 285/298;
403/321 |
Current CPC
Class: |
A47G
27/0493 (20130101); Y10T 403/59 (20150115) |
Current International
Class: |
A47G
27/00 (20060101); A47G 27/04 (20060101); A47g
027/04 () |
Field of
Search: |
;254/62,63,114,116,119
;287/58CT ;138/114,155 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Simpson; Othell M.
Assistant Examiner: Watson; Robert C.
Attorney, Agent or Firm: Harris, Kern, Wallen &
Tinsley
Parent Case Text
This is a continuation of application Ser. No. 186,085, filed Oct.
4, 1971 and now abandoned.
Claims
I claim:
1. An assembly of extendible, telescoping tubular members having
lock means preventing their retraction which comprises:
an outer tubular member;
an inner tubular member concentric in said outer tubular
member;
an elongated locking member secured at one of its ends in one of
said members with its opposite end projectintg within the other
tubular member and extending a substantial distance therealong;
lock means comprising a collar about said elongated member and
loosely carried by the other of said members by attachment means to
one edge of said collar to provide a free edge thereof that is
movable to permit tilting of said collar between a first position
in locking engagement with said elongated locking member to prevent
relative movement in one direction between said tubular members and
a second position releasing said collar from said elongated locking
member and permitting relative movement between said tubular
members in a direction opposite to said one direction;
resilient means engageable by seat means carried by said other of
said tubular members and biased against said collar to urge it into
said first position; and
release means engageable with said collar whereby the collar can be
manually moved from its said first to its second position.
2. The assembly of claim 1 wherein said elongated locking member is
secured to said outer tubular member and said lock means is carried
in said inner tubular member.
3. The assembly of claim 1 wherein said elongated locking member is
secured to said one of said members by attachment means permitting
a limited degree of radial movement of said tubular and elongated
locking members whereby said members will be in axial
alignment.
4. The assembly of claim 2 wherein said elongated member has at
said opposite end a bearing means in contact with the inner
periphery of said inner tubular member and wherein said bearing
means is attached to said elongated locking member by locking
member attachment means permitting a limited degree of radial
movement of said tubular and elongated locking members whereby said
members will be in axial alignment.
5. The assembly of claim 4 wherein both said elongated locking
member attachment means comprises a plug carried by said outer
member adjacent one end thereof, a central bore through said plug
and a screw of lesser diameter than said bore projecting
therethrough and into a threaded tap in the end and on the
centerline of said elongated member.
6. The assembly of claim 1 wherein said release means comprises a
rod extending along the inner member and eccentric thereto and
having one end engageable with the free edge of said collar,
actuating means carried adjacent the free end of said inner member
and link means interconnecting the opposite end of said rod with
said actuating means.
7. The assembly of claim 1 wherein said release means comprises a
third tubular member concentrically disposed within said inner
tubular member with one end thereof engageable against the free
edge of said collar, hand lever means carried at the free end of
said inner member, and link means interconnecting the opposite end
of said third tubular member with said lever means.
8. The assembly of claim 1 wherein said seat means comprises a
second collar surrounding said elongated locking member in a freely
sliding relationship and attached rigidly to said inner tubular
member.
9. The device defined by claim 1, in which one of the tubular
members is attached to the base of a power carpet stretcher having
a carpet engaging head, a handle pivotably attached to said head, a
link member having one end attached at one end in a fulcrum
relationship to said handle and pivotably attached at its other end
to said base, said handle having adjacent its outer end a hand
lever attached by a cable to the release means of the assembly and
movable to operate said release means.
Description
DESCRIPTION OF THE INVENTION
The invention relates to a locking, telescoping tubular member
assembly and, in particular, to such an assembly for use with
carpet installation equipment.
Carpet is commonly installed by stretching it across a floor with
tools that have a head which grips the carpet and a pole which
extends to a base or wall plate that is placed against a wall to
provide the support for the stretcher. The pole is commonly formed
of steel tubes which are furnished in units of two concentric tubes
which are approximately 31/2 feet long. These tubes can be extended
and interlocked at set intervals up to about 5 to 6 feet. The inner
tube carries a pair of spring biased buttons at each end while the
outer carries apertures at its ends so that the tubes can be
connected, head-to-tail, to provide a rigid load bearing pole.
This conventional construction prevents the most efficient use of
the stretcher equipment. The tubes can be interconnected only at
certain lengths which are determined by the location of the
apertures. For maximum usefulness, a stretcher head should be
capable of being located at any point from the base, however, the
limitation of the extensions to distances that are fixed by the
location of the apertures often results in gaps or blind spots
where the head can not be located.
The conventional stretcher head has a tube for connection to the
pole extension that has rows of several apertures to be engaged by
the buttons of the pole. Frequently, as the head is moved along the
wall, the buttons of the pole unit must be reset to extend the head
and/or the base must be moved along the opposite wall. The
resetting of the head using the buttons to interlock the stretcher
head to the pole unit or by moving the base is time consuming.
With conventional stretchers, the pole must be set at the proper
distance to position the head with a tolerance of only a few
inches. The head must then be engaged in the carpet to the correct
bite that will provide exactly the desired tension when the
stretcher handle is fully depressed. Accordingly, a considerable
degree of skill is required and even skillful operators frequently
must reset the head or the pole units before the desired tension is
achieved.
This invention eliminates the aforedescribed failings of the prior
pole units for carpet stretchers by providing an extendible pole
assembly which has a locking action at all points throughout its
extension. The invention, furthermore, provides a slip and lock
action whereby the head and/or pole units of the stretcher can be
moved across the floor by a simple pumping action on the handle or
by pulling on the tube behind the head. The pole assembly also
improves the efficiency in operation of the stretcher. Contrary to
the frequent resetting of the head which is necessary with
conventional stretchers to obtain the correct bite, this invention
permits the operator to simply drop the head at a position close to
its desired or final position. At this point the base can be away
from the opposite wall and the stretcher handle can be pumped to
extend the pole while retaining the head in place or the end of the
pole can simply be pulled by hand until the base has been moved
into position against the opposite wall. No difficulty is
experienced in obtaining the exact bite for the head because it can
be placed anywhere near the edge of the carpet, preferably
sufficiently near the edge that no substantial area will remain
unstretched. The stretcher handle can be operated throughout its
use in the lower portion of its arc where the maximum lever
advantage exists and, if the carpet is stretched taut before the
handle is fully depressed to a lock position, the excess or
remaining arc can be taken up by the sliding lock of the pole
assembly of this invention. When the pole assembly is used in the
preferred combination which includes the ratchet locking handle,
the sliding lock need not be used to take up the excess of the head
bite, but instead, the head can be locked at any of many of its
extensions.
The invention comprises an assembly of inner and outer concentric
tubular members which, preferably, are compatible with the tubes
commonly used in stretcher poles, i.e., are of the same shape and
diameters and bear at their outboard ends, the standard
interconnecting means such as the aforedescribed spring buttons and
mating apertures. The assembly has internal lock means formed of an
elongated lock member that is secured with one of its ends
attached, preferably with self aligning means, to one of the
tubular members adjacent the outboard end of such member and which
projects along the length of the members. The other of the tubular
members supports lock means comprising a collar which surrounds the
lock member by attachment means which, preferably, are also self
aligning and which permit the collar to tilt between a first,
locking position against the lock member and a second, releasing
position. Resilient means are provided between seat means carried
on the other of the tubular members and the collar in a biasing
position to urge the collar into the first, locking position.
Release means are also provided to engage the collar with link
means to the outside of the assembly to permit manual unlocking of
the assembly.
The invention will now be described by reference to the Figures of
which:
FIG. 1 illustrates the assembly of the invention;
FIG. 2 illustrates the assembly in a carpet stretcher assembly;
FIG. 3 illustrates the details of a preferred ratchet locking
stretcher to be used with the assembly of the invention;
FIG. 4 is a cross sectional view of the assembly of FIG. 1;
FIG. 5 is a view of an alternate embodiment of the invention;
and
FIGS. 6 through 8 show various alternate embodiments.
Referring now to FIG. 1, the device is shown as an assembly of two
concentric tubular members, outer tube 10 and inner tube 12 which
telescopes within tube 10. Preferably these tubes are compatible
with the conventional carpet stretcher tubes and tube 10 is 1.785
inches outside diameter and 1.645 inches inside diameter. Tube 12
is 1.625 inches outside diameter and 1.495 inches inside diameter.
The tubes are formed of steel, typically 10 -24 or 10-15 rolled
mild steel with welded seams. The tubes are commonly chrome plated.
Lighter weight aluminum or aluminum alloy tubes can also be used
and such tubes can be provided with a hard coating by anodizing or
by the Sanford process. Any of various means to interlock the tubes
can be used and such means are carried at the ends of the
tubes.
As illustrated, however, the outer tube 10 bears the conventional
apertures 14 at its free end which are spaced at 180.degree. in the
same plane and are positioned about 3.75 inches from the end. These
are female interlocking means to provide attachment whereby the
tube can be interlocked to smaller diameter tubes of pole units
which bear male interlocking means comprising opposed and spring
biased buttons at their ends to engage the apertures. One or more
sets of such apertures can be provided at the standard spacings
from the end of the tube to insure the universal compatibility of
the assembly with all stretcher poles.
The small diameter tube 12 bears, at its free end, a pair of spring
biased buttons 18. These buttons are conventional in structure and
purpose; they are the male interlocking means to permit the tube
assembly to be interconnected with standard stretcher components.
The buttons have a diameter of about 0.375 inch and project through
opposed apertures spaced about 1.25 inches from the free end of the
smaller tube. The buttons are commonly secured to the free ends of
a bifurcated, resilient leaf spring which fits into the end of the
tube.
The remainder of the tube assembly, externally, appears the same as
the conventional extendible units of stretcher systems except for
the absence of many apertures along the length of tube 10 and
except for the tube lock release means which is shown as collar 20.
As will be described in greater detail hereinafter, the collar 20
can be urged toward the tube 10 to unlock the assembly and permit
tube 12 to telescope into or be withdrawn from tube 10.
Referring to FIG. 2, the assembly is shown in a carpet stretcher
unit. The stretcher head unit comprises a plate 11 bearing teeth to
engage the carpet. The plate is attached to shaft 13 which slides
within tube 15. This tube is the base of the head unit and has a
link member 17 pivotably attached thereto. The other end of the
link member is attached to lever 19 to provide a fulcrum support
therefor. The end of lever 19 is pivotably attached to head plate
11.
Preferably, the head unit has means to permit locking shaft 13 at
any of a multiple of extension in tube 15 such as disclosed in my
copending application, Ser. No. 173,779 now U.S. Pat. No.
3,693,936, filed on Aug. 23, 1971. Such means can comprise rack
means 21 shown cut into shaft 13 with pawl means carried by tube 15
which also carries spring means to bias the pawl into engagement
with the rack means and actuation means, lever 23 carried by lever
19 with linking means such as cable 25 that is operative to retract
the pawl from the rack. Preferably such rack and spring means are
carried internally of tube 15 in the manner described in the
aforedescribed application. A head unit such as described herein is
commercially available as the KT-175 model from the Kindead
Industries Inc., Chicago, Illinois.
Alternatively, arcuarate rack means can be positioned on link 17
adjacent its pivotable connection to lever 19 and the pawl and
spring means can be carried by lever 19. Such a construction is
shown in FIG. 3 where the arcuate rack 24 is placed on link 17 on a
radius about pin 27 and pawl 29 is pivotably connected between the
sidewalls of lever 13 and biased into engagement with the rack by
spring 31 which is secured to arm 33 that is rigidly linked to the
pawl. A push rod 35 extends to lever 33 to retract the pawl 29.
Referring again to FIG. 2, the remainder of the stretcher unit
comprises one or more of the extendible tube assemblies of this
invention, tubes 10 and 12. Although the assembly can be
interlocked in the pole unit at any place in its length, it is
preferred to place one of the assemblies of the invention directly
behind the stretcher head unit so that the manual release means can
be readily available to the operator of the stretcher. The forward
end of tube 12 is interlocked by its buttons 18 into the end of
tube 15 of the head unit. Tube 10 is also connected to a tube
extension that is shown as a conventional extendible tube unit
formed of inner tube 35 which bears a first set of spring biased
buttons to interlock in apertures 14 and a second set of buttons to
interlock within any set of a plurality of apertures 37 along outer
tube 39 of the unit. The tubes are shown in FIG. 2 with a
disproportionately large diameter for ease of illustration.
A conventional wall block or plate 41 is carried at the end of tube
39 by shaft 43 which fits within tube 39 and which also has a pair
of spring biased buttons to interlock within the last of apertures
37 in this tube. Preferably, shaft 43 is attached to plate 41 with
bracket means permitting it to pivot in a horizontal plane relative
to plate 41.
Referring now to FIG. 4, the assembly of this invention is shown in
longitudinal section. The outer tube 10 carries a block 22
intermediate its length, preferably adjacent one end as shown and
spaced inwardly from apertures 14 sufficiently to avoid any
interference with the end of a mating tube and thereby permit
interlocking by buttons carried by such tube engaging apertures 14.
Typically, this distance is from 1.25 inches to about 2 inches from
the apertures. Block 22 comprises a cylindrical member that fits
inside tube 10 and is secured thereto by suitable means such as set
screws, welding or equivalent means. The block has means for the
attachment of the locking elongated member which is in the form of
tube 26. A solid shaft is shown for this member, however, it is
preferably tubular. The cross section of this member can also be of
any shape, e.g., square, oval, etc.
The preferred attachment means to secure member 26 to block 22 has
means that permits a limited radial displacement of tube 26. This
is preferred since the assembly of the tubes to an exact axial
alignment requires a high precision in manufacture. If however tube
26 is free to "float" slightly while still secured to block 22 the
manufacture is easier. The means permitting this radial
displacement of the tube assembly comprises end plugs 6 and 7 in
tube 26 which are bored and threaded along the centerline of the
tube. Block 22 bears a large diameter bore 8 and a screw 9 having a
shank of lesser diameter than bore 8. The screw extends through the
bore and into threaded engagement with the threaded bore in plug 6
and the tolerance between the shank of the screw and the bore in
plug 22 provides the limited degree of radial movement to tube 26
which imparts a self-aligning action to the entire assembly.
The free end of tube 26 projects substantially the entire length of
tube 10 and is concentrically disposed within inner tube 12. The
free end of this tube, preferably but not necessarily, bears a
short sleeve 28 that can be formed of brass, aluminum, or more
preferably of a plastic having a low coefficient of friction such
as Nylon, Teflon or Deldrin. This sleeve has a diamter sufficient
to engage the inner wall of tube 12, and is attached to tube 26 by
screw 34 and plug 7, the latter being secured to the tube by set
screws, welding or equivalent means. As with block 22, the bore
through sleeve 28 is slightly oversized to permit self alignment of
the tube assembly.
As thus described, the unit has two concentric and telescoping
tubular members with the inner tubular member being supported by an
internal bearing sleeve carried by a central member that is secured
at one end to the outer tube. While this construction could be
reversed, the illustrated embodiment is preferred. This
construction provides a telescoping assembly having a very smooth
action with little or no tendency for the elements to bind or
become misaligned even at full extension.
Sleeve 28 also servies as means limiting the extension of the
tubular members to prevent their separation. The rear face of this
sleeve will butt against the fore face of collar 32 and stop
further extension of the assembly when its full extension is
reached.
The inner tubular member carries the lock means which engages the
elongated locking member 26 in a slip and hold manner. The lock
means comprises a collar 32 which surrounds tube 26. This collar is
free to tilt to a slight angle, e.g., from 2.degree. to about
30.degree. to a plane perpendicular to tube 26. One solid collar
can be used as shown or a stack of several thin collars can be
stamped from sheet metal and used for this purpose.
One side of the collar 32 is fixed in the assembly. This is
accomplished by attachment means comprising an aperture in tube 12
and providing a finger or projection on one side of the collar 32
that extends into the aperture. Alternately, the attachment means
shown can be used wherein the collar is bored and a pin such as 36
can be placed through the bore and turned into a threaded
engagement with fixed means such as collar 30 that is also carried
by tubular member 12. Pin 36 has a shank 38 of reduced diameter
that passes through bore 45 and a head 40 to provide retaining
means for the edge of collar 32 and thereby permit the collar to
tilt slightly about this retaining attachment means between a
first, tilted position where it engages tube 26 in a lock that
prevents retraction of tubular member 12 within member 10 and a
more tilted position where it releases tube 26 and permits tubular
member 12 to retract within member 10.
A resilient means such as spring 42 is provided to bias collar 32
into its tilted, locking position. The spring seats against seat
means carried by tubular member 12, e.g., collar 30 and a bore 44
can be provided in the face of this collar to secure the spring.
The face of collar 32 is also bored and threaded at 46 and the
threaded end of rod 48 is turned into this bore. This rod comprises
the release means operative to unlock collar 32 and it extends
substantially the length of tubular member 12 and terminates
adjacent collar 20.
Sleeve 28 is bored at 50 and rod 48 extends through this bore. The
rod is attached to collar 20 by screw 52 and tubular member 12
bears an elongated aperture 54 through which screw 52 extends.
Screw 52 is secured to rod 48 by suitable means, e.g., by passing
it through a mating aperture in the rod. This aperture permits
sliding of collar 20 for a slight distance on tubular member 12
and, through rod 48, the retraction of the free edge of collar 32
against the bias of spring 42.
The abutment or seat means for spring 42 comprises the collar 30
which has a diameter slightly greater than tubular locking member
26 and which is secured to tubular member 12 adjacent its inside
end in the assembly with set screws, welding or equivalent
means.
The set of spring biased buttons 18 which comprise the male
interconnecting means for attachment of the assembly to
conventional stretcher tubes are shown at the left of tubular
member 12. The member bears opposed apertures and buttons 18
project through these apertures. The buttons are supported at the
free ends of bifurcated leaf spring 58. The latter is conventional
in construction, and any other means for spring biasing buttons 18
can be used such as by mounting the buttons in a sleeve with a
compression spring positioned between the inboard ends of the
buttons, etc.
An alternate embodiment of the invention is shown in FIG. 5. This
embodiment uses a concentric tube rather than the rod 48 and a
lever rather than collar 20 of the embodiment of FIGS. 1 and 4. As
illustrated, outer tubular member 10 is to the left of FIG. 5 and
bears block 22 and inner locking elongated member 26 with sleeve 28
and screws 9 and 34, all identical to those of FIG. 4, with
exception that sleeve 28 is of slightly lesser diameter to fit
within tube 60. As with the embodiment shown in FIG. 4, the inner
tube 26 has attachment means permitting radial movement of the
individual tubes, thereby insuring that the assembly is in axial
alignment. These means are the same as those described with regard
to FIG. 4.
The inner tubular member 12 and collar 30 supported thereon by set
screws such as 62 are also identical to the same elements of FIG. 4
with the exception that tubular member 12 bears an aperture 64 near
its inboard end. Collar 66 is slipped over member 26 and fits
within tubular member 12 and has a tail 68 that fits into aperture
64. A single large diameter compression spring 65 is placed between
collars 30 and 66 and comprises the resilient means to bias collar
66 forward into a locking position on tube 26.
The forward face of collar 66 has a maximum height above the face
of the collar on the side opposite finger 68. Tube 60 which engages
against the leading edge of rim 70 and projects forward in tubular
member 12 terminates therein near the opposite end of this member.
At the extreme outboard end of the tubular member 12, not shown,
are positioned female interlocking means such as buttons 18 and
spring 58 shown in FIG. 4.
A collar 72 is fitted on tubular member 12 and secured thereto by
set screws, welding or equivalent means. This collar bears bracket
means 74 for the pivotable support of lever means 76. Lever 76 has
a pin 78 or equivalent finger means which projects through an
elongated aperture 80 in and a similar aperture in tubular member
12. The free end of pin 78 projects into engagement with tube 60
which can have a small aperture in which the pin is seated. The
lever means and tube 60 thus comprise release means whereby the
locking engagement of collar 66 about tube 26 can be disengaged.
Pressing down on lever 76 will move tube 60 inwardly and force
collar 66 against the bias of spring 65.
Referring now to FIG. 6, a preferred embodiment of the invention is
shown. In this embodiment, the outer tube 10 bears block 22 by set
screws. The block is the same as that described with regard to FIG.
4 and it supports the elongated lock member, tube 26 with radial
adjustment means comprising oversized bore 8 in block 22 and cap
screw 9. The screw 9 is engaged in a threaded bore of plug 6 which
is secured to the end of tube 26. Tube 26 projects within the tube
assembly and bears a short sleeve 28 which serves as a bearing
support for the tube.
The inner tube 12 carries end plate 90 which has a rim 91 that
bears against the end of tube 12 and a body which fits within the
tube and is locked thereto by set screws, welding or equivalent
means. A second plate 92 is positioned transversely within tube 12
a short distance from the end of this tube and secured thereto by
any convenient attachment means such as plug welds 93. Both plates
90 andd 92 have a central, large diameter aperture which surrounds
tube 26 with a sufficient tolerance to permit the tube to be
slightly displaced in a radial direction in the assembly, e.g., the
diameter of this aperture is from 0.065 inch to about 0.125 inch
greater than the outside diameter of tube 26. Collar 28 has a
greater diameter than the aperture in plate 92 to provide means to
limit the extension of the assembly when the rear face of sleeve 28
butts against plate 92. The locking tube 26 is preferably formed of
hardened alloy steel, e.g., 4130 alloy steel which has been heat
treated to a high hardness. The tube could also be a solid shaft,
however, a hollow tubular member is preferred to minimize the
weight of the assembly. The locking collar can be cast iron, cast
steel or forged steel that is preferably case hardened to a
thickness of about 0.010 to 0.020 inch.
Collar 103 is a generally circular plate having a central aperture
which is at a slight angle, e.g., from 5.degree. to about
30.degree. , preferably, from about 2.degree. to 8.degree., to its
face. This aperture fits loosely about tube 26. A pin 94 is placed
in a bore on one face of the collar 103. This face of the collar
103 can be slightly raised as shown, however, this is not critical.
Plate 92 also has an aperture 95 which is placed at the same radial
distance from the center of plate 92 as pin 94 is from the center
of collar 103 so that the pin will project through the plate when
collar 103 is placed within the tube 12 as shown in FIG. 6. The
aperture 95 should be of suffucient diameter to permit pin 94
freedom of movement as collar 103 is moved between its varied
angular positions in the assembly. If desired, pin 94 need not be
secured on collar 103, but instead, it could be placed in aperture
95 and be provided with a head of larger diameter than aperture 95
to prevent the pin from being displaced from this aperture. The
head end of the pin would then bear against the collar 103.
A plate 87 is placed within tube 12 and this plate bears against
the side and edge of collar 103 which are opposite from pin 94 so
that the extremity of collar 103 is locked between this plate and
transverse plate 92. Resilient means, compression spring 96 is
placed around tube 26 and the lock housing is closed by securing
plate 90 to tube 12. Plate 90 has one or more tapped bores 97 that
are spaced at the radius of spring 96 and set screws can be
inserted into these bores to urge washer 102 against the tension of
spring 96 and thereby serve as means for adjustment of the tension
of this spring.
The free end of pin 94 projects through plate 92 and is engaged by
the inboard end of tube 60 which surrounds tube 26. The inboard end
of this tube can bear a plate such as 98 that serves to align the
tube and to bear against the end of pin 94. The opposite end of
tube 60 bears collar 104 which is bored and fitted at 99 with pin
means 100. The latter projects through an elongated aperture 101 of
tube 12 and serves as the manual release or as a linking member to
the manual release.
Various modifications can be made in the illustrated embodiments.
FIG. 7 shows a stack of thin sheets 120 which can be cut or stamped
from sheet metal and which can be assembled on tube 26 rather than
collar 103. These sheets would provide a multiple of gripping edges
as shown at 123 and 124 and thus could improve the locking action
of the device. After stamping the sheets are preferably heat
treated by conventional methods, e.g., by selective hardening
wherein the metal sheets are heated to a high temperature and then
quenched in an oil bath or cooled rapidly in air. Other methods
such as nitriding or carburizing can also be used.
FIG. 8 shows an alternate manual release which has a less sensitive
or less of a "hair trigger" action than that shown in FIG. 4. In
this embodiment, tube 12 carries bracket means 105 on its inside
surface adjacent the end of tube 60. A lever 106 is mounted on the
bracket and has a cam 107 which bears against collar 104 of tube
60. The free end of lever 106 projects through an elongated
aperture in tube 12 to serve as the manual release so that movement
of the lever will, through cam 107, urge tube 60 rearwardly and
release the locking collar 32.
FIG. 8 also illustrates use of a link 110 which is carried by the
stretcher unit and which can be connected to the manual release to
achieve remote actuation. In this embodiment, a cable such as 25 is
extended from a hand lever such as 23 shown in FIG. 2 that is
carried by the stretcher handle. The cable extends to a housing 111
which is attached to the end tube 112 of the stretcher by means
such as band 113.
Housing 111 has a slot 114 in its side walls and link 110 passes
through the slot and into the housing where it is secured to the
end of cable 25. The opposite end of link 110 can be dropped over
the end of lever 106 so that retraction of the cable will actuate
the lever and force the tube 60 rearwardly against the bias of the
spring, e.g., spring 96, and unlock the collar.
Housing 111 also can contain a spring means 115 shown through slot
114 which biases the link rearwardly. This spring is shown biased
against slide means in the form of block 116 within the housing
with link 110 being passed through a bore in this block. Cable 25
is secured to this block, either directly or by a shaft or pin.
In the illustrated embodiments, the pole extension is shown as a
separate unit that can be removably attached to a stretcher as
shown in FIG. 2. The extension unit, however, could be an integral
portion of the stretcher, e.g., tube 15 could be the same as tube
12 as shown in FIG. 2.
The operation of a stretcher equipped with a pole extension of this
invention is farily apparent from the preceding discussion. The
stretcher assembly as shown in FIG. 2 can be placed in
approximately the desired position on the carpet to be stretched
with the head of the stretcher dropped close to the final position.
The operator can then pull on the outer tube of the assembly to
move the base plate against the opposite wall. The teeth of the
stretcher can then be engaged in the carpet and the handle can be
pumped to take up the slack in the carpet. No difficulty is
experienced in setting the exact bite necessary for the last
movement of the handle since if an excessive bite is taken and the
carpet is stretched taut before the handle is fully depressed, the
operator can simply touch the manual release of the pole unit and
the remaining arc of the handle movement can be taken up by the
sliding or retraction of the pole assembly. The operator also need
not repeatedly engage and reset the teeth in the carpet while
taking up the slack in the carpet since the telescoping tube
assembly will provide ample extension with a single setting, e.g.,
from about 20 to 40 inches or more can be obtained, depending on
the overall length of the assembly in use. Since the sliding lock
on the unit permits locking of the assembly against retraction at
any point along its extension, the handle of the stretcher can be
used throughout the last portion of its arc, e.g., during the last
45.degree. to 15.degree. of its arc where the maximum lever
advantage exists. As the operator moves across the room, resetting
the head in successive steps along the wall, the base plate can
remain set at its original position against the opposite wall and
the increasingly greater lengths of the pole that are required can
simply be obtained by extending the sliding pole assembly. This
increase in length of the pole can be made almost unconsciously by
the operator simply by picking up the head, moving it to the new
position and dropping it into the carpet at the new position. The
weight of the pole extension and the base will generally be
sufficient to retain the base against the wall during this
operation; if the base should be dragged from the wall, it can be
easily returned by pulling on the outer tube of the assembly or by
pumping on the handle of the stretcher.
The invention has been described with reference to the presently
preferred and illustrated embodiments. It is not intended by this
illustration that the invention be unduly limited but rather it is
intended that the invention be defined by the means and their
obvious equivalents set forth in the following claims.
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