U.S. patent number 3,854,774 [Application Number 05/386,043] was granted by the patent office on 1974-12-17 for swing-away footrest for invalid wheelchairs.
This patent grant is currently assigned to Gendron-Diemer, Inc.. Invention is credited to Paul D. Limpach.
United States Patent |
3,854,774 |
Limpach |
December 17, 1974 |
SWING-AWAY FOOTREST FOR INVALID WHEELCHAIRS
Abstract
A swing-away footrest assembly for invalid wheelchairs having an
improved latching mechanism for effectively locking the footrest in
a position of use and facilitating unlocking the footrest to permit
the same to be swung to a position of non-use or completely removed
from the wheelchair.
Inventors: |
Limpach; Paul D. (Napoleon,
OH) |
Assignee: |
Gendron-Diemer, Inc. (Archbold,
OH)
|
Family
ID: |
23523919 |
Appl.
No.: |
05/386,043 |
Filed: |
August 6, 1973 |
Current U.S.
Class: |
297/423.37;
248/408 |
Current CPC
Class: |
A61G
5/128 (20161101); A61G 5/125 (20161101); A61G
5/12 (20130101) |
Current International
Class: |
A47C
7/00 (20060101); A47C 7/52 (20060101); A61G
5/12 (20060101); A61G 5/00 (20060101); A47c
007/50 () |
Field of
Search: |
;297/417,429,433
;248/407-409 ;5/331 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nunberg; Casmir A.
Attorney, Agent or Firm: Wilson; David H.
Claims
What I claim is:
1. A latching mechanism for releasable locking a swinging footrest
assembly to an adjacent part of a wheelchair upon which the
footrest is pivotally supported to swing about a vertical axis
comprising:
a plunger affixed to said part normally biased to a latching
position, said plunger mounted to reciprocate along an axis;
a washer-like means affixed to said footrest for selective
engagement with said plunger; and
lever means pivotally mounted on said part for reciprocating said
plunger out of latching position.
2. The invention defined in claim 1 includes a helical spring for
biassing and plunger.
3. The invention defined in claim 1 wherein said lever includes an
elongate slot for receiving one end of said plunger.
4. The invention defined in claim 3 wherein the opposite end of
said plunger is hemispherical in shape.
5. The invention defined in claim 1 wherein said plunger is mounted
to reciprocate along an axis normal to said vertical axis.
Description
BACKGROUND OF THE INVENTION
Efforts have been made to develop swingable and removable
footrests. However the assemblies in the prior art have required
locking pins which had to be physically or bodily removed to enable
the footrest to be swung away from a locked position of non-use or
completely removed from the wheelchair. The obvious problem is
encountered should the locking pins be misplaced or lost. Such
structure is illustrated for example in U.S. Pat. No. 2,592,449
entitled "Removable Footrest for Wheel Chairs."
Other attempts to produce an acceptable mechanism have included a
spindle arrangement received in a vertically mounted and slotted
socket on the front post of the wheelchair. In order to lock the
footrest, a lever must be swung about a horizontal axis into a
slotted head of the spindle to secure the footrest in a
foot-supporting position. Manifestly such an operational mode
requires a separate operation with a different motion from the
actual mounting and swinging of the footrest into a working
position.
SUMMARY OF THE INVENTION
The present invention has produced a latching and locking mechanism
for a removable and swingable footrest assembly for wheelchairs
which overcomes the problems of the prior art wherein the latching
and unlatching of the removable and swingable footrest is
accomplished by single integrated movement of a latching lever and
swinging of the footrest. More specifically, the footrest may be
readily swung to a position adjacent the side of the wheelchair, by
merely depressing a latch arm against the bias of an associated
spring which withdraws a plunger from a recess in the footrest, and
thence swinging the footrest from the operative to the inoperative
positions. In order to effect a movement of the footrest from the
inoperative position to the operative position, the footrest is
merely caused to be swung about its vertical mounting axis so as to
cause the footrest to cam the plunger against the bias of the
spring until a recess in the footrest aligns with the plunger, at
which moment the plunger is biassed to a locked position positively
securing the footrest in the operative position.
The objects of the invention are effectively achieved by a latching
mechanism for releasably locking a swinging footrest assembly to an
adjacent part of a wheelchair upon which the footrest is pivotally
supported to swing about a vertical axis comprising a plunger
affixed to the part normally biassed to a latching position, the
plunger mounted to reciprocate along an axis; a detent on the
footrest for engagement with the plunger; and means for
reciprocating the plunger out of latching position.
BRIEF DESCRIPTION OF THE DRAWINGS
The above, as well as other objects and advantages of the invention
will become manifest to one skilled in the art from reading the
following detailed description when cconsidered in the light of the
accompanying drawings, in which:
FIG. 1 is a fragmentary side elevational view of a wheelchair
having a swingable footrest embodying the features of the
invention;
FIG. 2 is an enlarged fragmentary view of the latching and locking
mechanism of the invention;
FIG. 3 is a sectional view of the mechanism illustrated in FIG. 2
taken along line 3--3 thereof;
FIG. 4 is a view similar to FIG. 3 showing the footrest in an open
and unlatched condition; and
FIG. 5 is an elevational view of the structure illustrated in FIG.
4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings FIG. 1 illustrates a portion of an
invalid wheelchair which typically comprises two opposed side frame
members which generally are of the type capable of being collapsed
toward one another for purposes of storage and shipping. Each of
the side frames generally indicated by reference numeral 10 is
formed from tubular metal stock which contributes substantial
strength and light overall weight to the construction. As
illustrated, each side frame 10 has a front generally vertically
extending tubular member 12, the upper portion of which is bent
rearwardly into a horizontal portion 14 constituting an armrest.
Pivotally mounted to the bottom portion of each of the vertically
extending tubular members 12 is a caster assembly 16 for effecting
support of the front portion of the wheelchair.
The individual side frame members 10 may be connected one to the
other by means of the conventional diagonal cross brace structure
which consists of a pair of X-braces, each formed by two diagonal
rods. The rods may be connected together intermediate the ends
thereof to satisfactorily enable the side frames to be folded one
toward the other for purposes of storage.
In accordance with the present invention, forwardly extending
footrest assemblies 18 are swingably supported on the vertically
extending tubular member 12 to project forwardly of the wheelchair
frame. Each of the footrest assemblies 18 consists of a tubular
member 20, the upper portion of which is pivotally connected to the
upper portion of a tubular member 22 the lower end of which is bent
to extend outwardly and terminate in a spoke 24 to receive and
support the pivotally connected member 20.
The lowermost end of the tubular member 20 receives in a
telescoping fashion one end of a tubular member 26, the other end
of which is provided with a treadle or footrest 28 which is
hingedly or swingably mounted thereto between limits. The vertical
disposition of the footrest 28 may be varied by removing a threaded
fastener 30 which is adapted to extend through pairs of aligned
apertures in the tubular member 20 and selectively through pairs of
aligned apertures in the tubular member 26. The raising or lowering
of the tubular member 26 and its associated treadle 28 is effected
by withdrawing the fastener 30, moving the tubular member 26, and
reinserting the fastener 30 at the desired level.
A pair of spaced apart plate members 32 and 34 are mounted on the
vertically extending portion of the tubular member 22 to project
outwardly and rearwardly thereof. The plate members 32 and 34 are
each provided with an aperture 36, and 38, respectively. The
apertures 36 and 38 are disposed radially outwardly from the
tubular member 22.
A U-shaped bracket or saddle 40 having diametrically spaced tapered
slots 42 and 44 and vertically downwardly projecting portions 46
and 48. On the tubular member 12 are upper and lower transverse
pins 50 and 52 respectively. The slots 42 and 44 are adapted to
seat onto the upper transverse pin 50 of the wheelchair frame
member. The projections 46 and 48 extending downwardly from the
bottom of the saddle 40 are adapted to contact the rearward side of
the lower transverse pin 52. To effect a connection between the
saddle 40 and the tubular frame member 12 of the wheelchair frame
10, the saddle 40 is caused to embrace the tubular member 12 at a
point the slots 42 and 44 are above the transverse pin 50 and the
downwardly extending projections 46 and 48 are above the transverse
pin 52. The saddle 40 is then allowed to be lowered such that the
extremities of the transverse pin 50 engage within the slots 42 and
44 and the extremities of the transverse pin 52 engage the upper
portion of the tapered downwardly extending projections 46 and 48
such that a snug fit is achieved between the saddle 40 and the
associated tubular member 12.
A pair of outwardly extending bracket members 54 and 56 are secured
by welding to extend outwardly from the saddle 40. The bracket
members 54 and 56 are spaced apart an amount substantially equal to
the spacing between the associated plate members 32 and 34 of the
footrest assemblies. The bracket members 54 and 56 are each
provided with an upwardly extending pin member 58 and 60,
respectively. Preferably, the lower pin 60 is somewhat longer than
the upper pin 58, so that in applying the footrest assembly 18 to
the saddle 40, the lower pin 60 may be caused to enter its
associated aperture 36 in the member 32 before the upper pin 58
enters its associated aperture 38 in the member 34. Thus, with the
entry of the lower pin into the aperture 36 in the lower plate 32,
the upper pin 58 can be easily guided into the associated aperture
in the plate 34 and entire footrest assembly 18 allowed to be
lowered into place during assembly when the elements are in the
position illustrated in FIGS. 4 and 5.
Then the footrest assembly 18 may be swung toward the latched or
locked position illustrated in FIGS. 1, 2 and 3. To maintain the
footrest 18 in a locked position with respect to the wheelchair
frame 10 and the saddle 40, an improved latching mechanism is
employed. The latching mechanism includes an outwardly extending
mounting bracket 64 which is welded or otherwise secured to the
outer wall of the saddle 40. A cylinder 66 is secured, by welding
for example, to the bracket 64. A plunger 68, adapted for
longitudinal movement, is disposed within the interior of the
cylinder 66. One end 70 of the plunger 68 generally hemispherical
in shape and normally biassed by a helical spring 69 to the
latching position as clearly illustrated in FIGS. 3 and 4. The
opposite end of the plunger 68, is provided with exterior threads
to receive a threaded fastener 72.
A lever 74, formed of sheet metal, for example, has ears 76 and 78
struck outwardly out of the plane of the lever body to contain an
integral pivot pin 80 therebetween. The pivot pin 80 is adapted to
pass through a suitable aperture in the bracket 64. Spacer means 82
and 84 may be employed to position the lever 74 with respect to the
bracket 64. One end of the lever 74 is provided with a slot 86 of a
width sufficient to permit the passage of the threaded portion of
the plunger 68 but narrower in width than the threaded fastener
72.
A curved washer 88 is brazed or otherwise suitably secured to the
outer wall of the tubular member 22 of the footrest 18. Preferably,
after the washer 88 is secured to the member 22, the member is
drilled to form an aperture aligned with the aperture in the washer
88.
As mentioned earlier, the footrest assembly 18 may be readily moved
from the open or unlatched position illustrated in FIGS. 4 and 5 to
the latched position illustrated in FIGS. 1, 2 and 3. As the
pivotal movement of footrest 18 occurs, the outwardly projecting
portion 70 of the plunger 68 is caused to contact the curved outer
surface of the washer 88 which tends to cam the plunger 68
rearwardly against the bias of the helical spring 69. When the
portion 70 of the plunger 68 aligns with the apertures of the
washer 88 and the tubular member 22, the spring 69 causes the
portion 70 to seat within the apertures and thereby suitably lock
the footrest 18. To insure for a firm and quiet connection, a
resilient bumper 90 is affixed to the member 22 so that in the
latched position, the bumper 90 is slightly compressed between the
tubular member 22 and the outer wall of the saddle 40.
To move the footrest 18 to a position of non-use or to remove it
from the side frame 10, the lever 74 is moved in a clockwise manner
(as viewed in FIG. 3) about the pivot pin 80. The portion of the
lever 74 which defines the slot 86 will thereupon contact the
undersurface of the threaded fastener 72 and thereby urge the
plunger 68 against the bias of the spring 69 to unseat the plunger
end 70 from the apertures in the washer 88 and the tubular member
22. With continuing pressure on the lever 74, the entire footrest
18 will tend to swing about the pins 58 and 60. Manifestly when the
plunger end 70 is free from the locking apertures, the footrest may
also be grasped and swung to a position of non-use alongside the
side frame 10 of the wheelchair.
In the event, it is desired to entirely remove the footrest
assembly 18 from the side frame 10 of the wheelchair the footrest
18 need only be moved to an unlatched position as in FIGS. 4 and 5
and pulled upwardly until the members 32 and 34 are each above
their respective pins 58 and 60.
In accordance with the provisions of the patent statutes, I have
explained the principle and mode of operation of my invention and
have illustrated and described what I now consider to represent its
best embodiment. However, it must be understood that within the
spirit and scope of the appended claims, the invention may be
practiced otherwise than as specifically illustrated and
described.
* * * * *