U.S. patent number 3,663,967 [Application Number 04/758,031] was granted by the patent office on 1972-05-23 for joint movement limiting arrangement for prosthetic legs.
Invention is credited to Clarence W. Vermillion.
United States Patent |
3,663,967 |
Vermillion |
May 23, 1972 |
JOINT MOVEMENT LIMITING ARRANGEMENT FOR PROSTHETIC LEGS
Abstract
A stop arrangement for a joint of an artificial leg is described
which normally limits pivotal movement of a leg portion connected
to the joint to a predetermined extent commensurate with stable
walking on the leg. The arrangement includes a stop in the joint
which prevents over travel of the leg portion connected to the
joint and buckling of the leg under the amputee. The stop mechanism
is selectively releasable to permit full pivotal movement of the
joint as required for sitting, or the like and, if desired, may be
locked in the released position.
Inventors: |
Vermillion; Clarence W.
(Roseburg, OR) |
Family
ID: |
25050197 |
Appl.
No.: |
04/758,031 |
Filed: |
September 6, 1968 |
Current U.S.
Class: |
623/31; 623/38;
623/43; 403/112 |
Current CPC
Class: |
A61F
2/605 (20130101); A61F 2/604 (20130101); Y10T
403/32549 (20150115) |
Current International
Class: |
A61F
2/60 (20060101); A61f 001/08 (); A61f 001/04 () |
Field of
Search: |
;3/14-17,2,21,22-29
;287/92,99 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Temporary Prostheses For Lower Extremity Amputees, Pamphlet TR-1,
VA Prosthetics Center, 252 Seventh Ave., New York, 1 N.Y. Sept. 1,
1962, pages 5, 6, 10, 12, 13 and 15-16..
|
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Frinks; Ronald L.
Claims
I claim:
1. An articulated joint arrangement for an artificial leg having
first and second portions, said joint arrangement comprising a
first mounting means adapted for securance to a first portion of
the leg and being provided with a hinge collar, a second mounting
means adapted for securance to a second portion of the leg, said
first and second mounting means being hingedly secured together for
pivotal movement with respect to one another in at least a first
direction to provide an articulated joint between said leg
portions, and stop means carried by said first and second mounting
means for preventing pivotal movement thereof in said first
direction beyond a predetermined angular relationship of said leg
portions, said stop means being selectively releasable to permit
further pivotal movement in said first direction; said second
mounting means being in the form of a yoke adapted for securance to
said second leg portion and having spaced legs, said yoke being
hingedly secured to said first mounting means by a pivot pin
extending between the legs of said yoke and through a hinge collar
of said first mounting means; said stop means including a stop lug
projecting from said first mounting means, a stop block mounted
between the legs of said yoke for movement transversely
therebetween between first and second positions respectively
engageable with and non-engageable with said lug, and means coupled
to said stop block for selectively moving the same between said
first and second positions; said selectively moving means
comprising a plunger pin extending through said spaced legs of said
yoke and through said stop block, a collar fixedly secured to said
pin between said block and one of said legs of said yoke, and a
compression spring coaxially disposed on said pin between said
block and the other leg of said yoke.
2. An artificial leg comprising a bucket adapted to be strapped
about the waist of a wearer and receive the remaining portion of a
hip, a yoke mounting means for hingedly connecting a yoke to said
bucket, a yoke engageable with said mounting means to stop pivotal
movement of said yoke in the rearward direction relative to said
bucket, a thigh portion secured to said yoke, a knee joint secured
to said thigh portion, a shank portion secured to said knee joint,
and stop means carried by said mounting means and yoke for limiting
pivotal movement of said yoke in the forward direction relative to
said bucket to a predetermined extent, said stop means being
selectively releasable to permit unlimited pivotal movement of said
yoke in said forward direction; said mounting means being a plate
secured to said bucket, said yoke being of U-shaped configuration
with parallel spaced legs hingedly connected to said plate and a
web interconnecting said spaced legs, said stop means including a
stop lug projecting from said plate, a stop block carried by the
web of said yoke for movement between first and second positions
respectively engageable and non-engageable with said lug, and means
coupled to said stop block for selectively moving the same between
first and second positions.
3. An artificial leg according to claim 2, further defined by the
selective moving means comprising a plunger pin extending through
said spaced legs of said yoke and through said stop block, a collar
fixedly secured to said pin between said block and one leg of said
yoke, and a compression spring coaxially disposed on said pin
between said block and the other leg of the yoke.
Description
BACKGROUND OF THE INVENTION
In the field of prosthetics, various artificial legs have been
devised to enable the amputee to resume walking. In the case of an
amputee having a leg removed above the knee or hip joint, a
suitable artificial leg requires mechanical counterparts of the
missing joints in order that leg movement may be effected.
Heretofore, artificial legs for replacing legs removed above the
hip joint have included a pivot joint connecting the thigh portion
to a bucket adapted to be strapped about the waist and receive the
remaining portion of the trunk of the amputee. The joint typically
includes a stop to prevent excessive rearward movement of the leg,
while forward movement is resiliently constrained by a stiff
resilient strap connected between the bucket and the shank or lower
portion of the leg. The strap is such as to resiliently retain the
leg in vertical position with the joint engaging the stop. The leg
may be thrust forward, by appropriate movement of the wearer,
against the restoring force of the strap to a forward position in
engagement with the ground surface. The restoring force then
facilitates return of the leg to vertical position in the
completion of a step. However, extreme care must be taken that the
leg is not thrust too far forward beyond a dead center position
wherein the leg will continue to pivot forward rather than be
returned rearward and thus buckle beneath the wearer. Although
disadvantageous in walking, this movement beyond dead center
position permits the leg to assume a horizontal position to enable
the wearer to sit. Existing knee joints employed in artificial legs
are basically similar to the above described conventional hip
joints insofar as they limit movement in one direction, while
permitting constrained movement in the opposite direction. However,
with a knee joint the directions are reversed, forward movement
being limited and constrained, rearward movement being permitted.
Under some circumstances rearward movement of the knee joint may be
excessive and cause buckling of the leg under the wearer.
SUMMARY OF THE INVENTION
The basic object of the present invention is to provide selectively
releasable stop means in a joint for an artificial leg for limiting
the intended constrained movement of a leg portion connected to the
joint to a non-excessive amount during walking to prevent
inadvertent buckling of the leg under the wearer. Upon release of
the stop means by the wearer, the joint if freed for conventional
full movement to enable the wearer to assume a sitting position.
The joint includes a first mounting means for connection to the
bucket, in the case of a hip joint, or to the thigh portion of the
leg in the case of a knee joint. A second mounting means is adapted
for securance to a lower portion of the leg, and the two securing
means are hingedly secured together for pivotal movement with
respect to one another. In accordance with the particularly salient
aspects of the invention, a stop lug is rigidly secured to one of
the mounting means, and a stop block is carried by the other. The
stop block is selectively movable between a normal position
engageable with the stop lug to prevent excessive pivotal movement
of the joint, and a release position non-engageable with the lug to
permit conventional full pivotal movement of the joint. Thus,
pivotal movement of the joint is limited to prevent buckling of the
leg while free pivotal movement may be provided as required to
permit sitting, etc. A lock is provided for locking the stop block
in the release position whenever desired, such as when a joint
actuation or control mechanism is utilized with the leg.
An artificial leg in accordance with the invention may be arranged
to include a stopped hip joint in combination with a conventional
knee joint, a stopped knee joint alone in instances where the
wearer has a thigh stump, or a stopped hip joint and a stopped knee
joint. In the latter case, the leg may be arranged to facilitate
simultaneous release of the stops of both joints under the control
of a single release actuator. The leg may be arranged to permit
adjustment of the length of the pivotal leg portion connected to
each joint, as well as variation in the extent of limited pivotal
movement thereof to accommodate the needs of the individual
wearer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view with portions broken-away of an
artificial leg in accordance with the present invention, the leg
including a stopped hip joint and conventional knee joint and being
depicted in standing position.
FIG. 2 is a view similar to FIG. 1, but depicting the leg in
stopped forward position in the taking of a step.
FIG. 3 is a view similar to FIGS. 1 and 2, but depicting the leg in
stop released forward position assumed in sitting, or the like.
FIG. 4 is an exploded perspective view of the stopped hip joint
arrangement of the leg.
FIG. 5 is a front elevational view with portions broken-away of the
joint arrangement.
FIG. 6 is a sectional view taken at line 6--6 of FIG. 5.
FIG. 7 is a partial perspective view of the stop block plunger pin
depicting a bayonet lock arrangement by which the stop block may be
selectively locked in a release position.
FIG. 8 is a perspective view of a modified form of joint in
accordance with the present invention arranged for use with
existing artificial legs.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, FIGS. 1-3 in particular, there is
shown an artificial leg 11 for an amputee having the leg removed at
or above the hip joint. As is conventional, the leg includes a
bucket 12 which may be strapped about the waist of the wearer and
is adapted to receive the portion of the trunk remaining after the
amputation is performed. A thigh portion 13 is hingedly secured to
a small leg portion depending from the bucket by means of a
mechanical articulated hip joint 14. The thigh portion includes a
cover 16 or hard plastic, or the like.
In accordance with standard practice, the joint 14 is arranged to
limit pivotal movement of the thigh portion 13 in the rearward
direction to a substantially vertical position, as shown in FIG. 1,
and to permit constrained pivotal movement in the forward direction
to enable the leg to assume a walking position, as shown in FIG. 2,
or a sitting position, as shown in FIG. 3. In this regard, a
stiffly resilient strap 17 of hard rubber or the like is secured
between a point on the bucket rearward of the joint 14 and a point
adjacent the lower end of the cover 16. Thus, the strap resiliently
constrains the forward pivotal movement of the thigh portion 13,
and when same is thrust forward, as shown in FIG. 2, the strap
tends to return the thigh portion rearward to vertical position as
shown in FIG. 1. However, when the thigh portion is thrust too far
forward, it exceeds a dead center position and the strap pulls the
thigh portion forward and upward. This is necessary in order that
the thigh portion may assume the horizontal sitting position
depicted in FIG. 3.
The leg illustrated in FIGS. 1-3 is also provided with a
conventional lower leg or shank portion 18 pivotally connected to
the thigh portion 16 by means of a conventional knee joint 19, of,
for example, the constant friction counterweighted variety. Such a
joint limits forward pivotal movement of the lower leg portion to a
substantially vertical position and permits constrained rearward
movement thereof. As in the case of the hip joint, the knee joint
has a dead center position beyond which movement of the lower leg
portion will continue rearwardly.
It will be appreciated that although the over movement of both the
hip and knee joints is required to permit sitting, it is
undesirable in walking. In accordance with the present invention,
an articulated joint arrangement is provided which facilitates
selective prevention of the pivotal movement of one of the leg
portions with respect to another beyond the dead center position
during walking, and release of the joint to permit conventional
full pivotal movement for sitting. More particularly, with regard
to the hip joint 14, and referring to FIGS. 4-7, it is to be noted
that same includes a first mounting means in the form of a plate 21
secured to the bucket 12, as by means of screws 22. A second
mounting means in the form of a U-shaped yoke 23 is pivotally
connected to the plate, and a shaft 24 is secured to the web of the
yoke to depend therefrom interiorly of the cover 16 and define the
core of thigh portion 13. Shaft 24 is adjustable in length to
accommodate the needs of the individual wearer. In this regard, the
shaft is preferably comprised of telescoping inner and outer
sections 20 and 25 which may be locked together by set screws as
shown.
The lower end of shaft 24 is provided with an outwardly flared
annular flange 26 to facilitate securance to a disc member 27 of
the conventional knee joint 19. Pivotal connection of the yoke to
the plate is preferably facilitated by means of a sleeve or collar
28 fixedly secured to the plate and fitted with ball bearings 29 in
its opposite ends. A headed pivot pin 31 extends through the
parallel spaced sides or legs of the yoke, the bearings 29, and
sleeve 28 to receive a cap screw 32 and thus complete the pivotal
connection.
The previously mentioned selective limiting and release of pivotal
movement in a first direction is preferably facilitated by means of
a stop lug 33 which projects outwardly from sleeve 28 and
terminates in a face 30 which is engageable with a selectively
movable stop block 34 carried by the yoke 23. The yoke has a
V-shaped rear end portion 36 between the parallel spaced sides
thereof, and the upper face of the end portion engages the plate 21
to limit rearward pivotal movement to a position wherein the thigh
portion 13 is substantially vertical. The block 34 then includes a
V-shaped end 37 conformed to the end portion 36 of the yoke. A
headed bushing 38 is threadably received in and extends through one
of the sides of the yoke to project interiorly therefrom, and a
headed plunger pin 39 extends through an aperture in the opposite
side of the yoke and is received in the bushing. The pin also
extends through the lock 34 and a rectangular collar 41 on the
opposite side of the block from the bushing. The collar is fixedly
secured to the pin 39 as by means of a set screw 42 and is of a
length to extend between the block and side of the yoke when the
block is in a first position engageable with the lug 33. In this
regard, it is to be noted that a cushioning washer 40 is provided
on pin 39 between block 41 and the side of the yoke. A spring 43 is
coaxially disposed on the pin 39 with one end engaging one of the
sides of the yoke concentrically with the bushing 38 and the other
end engaging the block. The spring is in compression and thus
resiliently urges the block away from the bushing to a position
determined by the collar 41 engaging the opposite side of the yoke,
as shown in full line in FIG. 5. As previously noted, the block is
engageable with the lug in this position. The headed end of the
plunger pin is also extended from the side of the yoke. Upon
forward pivoting of the yoke when the thigh portion 13 is thrust
outward as shown in FIG. 2, the block hence engages the lug, as
shown in phantom line in FIG. 6, to prevent excessive pivotal
movement of the thigh portion beyond dead center position. When it
is desired to sit and full pivotal movement is required, the
plunger pin 39 is depressed to a second position depicted in
phantom lines in FIG. 5 to in turn translate the block out of
engagement with the lug. The yoke is thus free to pivot to the
extent required. Once the yoke has pivoted the edge of block 34
past face 30 of lug 33, the side of the lug maintains the block in
the released position so that it is unnecessary for the user to
hold it in such position against the pressure of spring 43. When
the wearer stands and the yoke pivots rearward, the spring 43 urges
the block and plunger pin to their normal position once the edge of
the block passes by the face 30 and stopped forward pivotal
movement is restored.
In some instances, it is desirable that the leg joint be freely
pivotal without interference by the stop block even when the wearer
is standing. For example, if the leg includes a joint control or
actuation mechanism the wearer may wish to override the pivot
limiting stop means. As an important feature of the invention,
means are provided for selectively locking the stop block in the
second position and out of the way of travel of the stop lug. With
reference to FIG. 7, bushing 38 includes a longitudinally extending
slot 44 which terminates at its inner end in a transverse slot 46.
A pin 47 radially projects from plunger pin 39 to normally ride
within slot 44. Upon actuation of the plunger pin to translate
block 33 to its second, releasing position, pin 47 becomes located
at the inner end of slot 44 adjacent slot 46. Rotation of plunger
pin 39 in the direction of arrow 48 in FIG. 7 will thus cause pin
47 to enter slot 46, thereby locking pin 39 in its plunged position
and block 33 in the release position. The head 49 of plunger pin 41
includes a diametrically extending projecting rib 51 to facilitate
gripping of the head to cause the pin rotation whenever it is
desired to so lock the block in the release position.
Referring now to FIG. 8, there is shown a modified form of the
joint which is arranged for use with a wooden leg. The modified
joint 14' is generally similar to that previously described except
that the yoke 23' includes a pair of parallel spaced straps 51
depending from the opposite sides thereof. The straps are provided
with vertically spaced apertures 52 for receiving screws to be
threaded into a wooden thigh portion inserted therebetween. The
provision of more than one set of apertures in the straps permits
adjustment of the length of a leg to accommodate the needs of an
individual wearer.
While the locking arrangement of the invention has been described
in connection with the hip joint of an artificial leg, it will be
appreciated that it could also be utilized in a knee joint.
Moreover, hydraulic or other control means may be used to effect
movement of the stop means between the pivot releasing and limiting
positions, such as when it is desired to actuate the stop means
from a location remote from the joint in which it is
incorporated.
* * * * *