U.S. patent number 3,826,251 [Application Number 05/320,957] was granted by the patent office on 1974-07-30 for locking knee joint for orthopedic leg brace.
Invention is credited to Charles Ross.
United States Patent |
3,826,251 |
Ross |
July 30, 1974 |
LOCKING KNEE JOINT FOR ORTHOPEDIC LEG BRACE
Abstract
A pivoted knee joint for an orthopedic leg brace provides for
both pivoting and relative sliding movement. When the user's weight
is placed on the braced leg and the leg is substantially straight,
the joint is locked against pivoting but is freely pivotable when
the leg is lifted. If the weight of the user is placed on the leg
while the leg is partially bent at the knee, the joint locks
against pivoting to prevent collapse of the user.
Inventors: |
Ross; Charles (Bethesda,
MD) |
Family
ID: |
23248570 |
Appl.
No.: |
05/320,957 |
Filed: |
January 4, 1973 |
Current U.S.
Class: |
602/16; 602/23;
623/44 |
Current CPC
Class: |
A61F
2/646 (20130101); A61F 5/0123 (20130101); A61F
2005/0158 (20130101); A61F 2005/016 (20130101) |
Current International
Class: |
A61F
2/60 (20060101); A61F 5/01 (20060101); A61F
2/64 (20060101); A61f 003/00 () |
Field of
Search: |
;128/8F,8R,8A
;3/27,26,28,29,22 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Yasko; J.
Attorney, Agent or Firm: Bacon & Thomas
Claims
I claim:
1. A joint between upper and lower portions of an orthopedic knee
brace, said portions having laterally spaced elongated members
adapted to receive a user's knee therebetween and means for
securing said brace to a leg of the wearer with the wearer's knee
between said members, comprising:
at least one elongated lower member having a longitudinal slot
therethrough adjacent the upper end thereof;
the corresponding elongated upper member having a first transverse
pin adjacent its lower end slidably positioned in said longitudinal
slot;
cooperating means on said members guiding said members for only
relative pivotal movement about the axis of said pin and only when
said pin is at the upper end of said slot and permitting
substantial downward movement of said pin in said slot only when
said members are substantially longitudinally aligned; and
interengageable means on said leg members, movable into engagement
when said pin moves downwardly in said slot, to hold said leg
members against relative pivoting in either direction.
2. A joint as described in claim 1 including resilient means urging
said interengageable means to disengage.
3. A joint as defined in claim 2 wherein said interengageable means
includes a longitudinally facing socket on one of said members and
detent means on the other member seatable in said socket, said
resilient means comprising a spring pressed plunger extending into
said socket from the bottom thereof.
4. A joint as defined in claim 1 wherein said cooperating means
include, an arcuate slot in said upper member, concentric to said
first transverse pin and a second transverse pin on said lower
member, slidable in said slot; said slot having a generally radial
slot portion at one end thereof extending generally upwardly from
said second transverse pin when said members are substantially
longitudinally aligned.
5. A joint as defined in claim 3 including a surface portion on
said one member for guiding said detent means into said socket.
6. A joint as defined in claim 4 wherein the lower end of said
upper member comprises laterally spaced plate portions and the
upper end of said lower member comprises a single plate portion
slidably and rotatably received between said spaced plate portions;
said first transverse pin extending between said spaced plate
portions and said arcuate slot being formed in at least one of said
spaced plate portions.
7. A joint as defined in claim 1 wherein said members are
respectively provided with openings therethrough that are in
alignment when said members are longitudinally aligned whereby a
locking member may be selectively positioned in said aligned
openings to lock said members against relative movement.
8. A joint as defined in claim 1 including cooperating locking
means on said members positioned to be freely movable past each
other when said members pivot about each other with said first
transverse pin at the upper end of said longitudinal slot but being
brought into locking engagement when said first transverse pin
moves a small distance downwardly in said longitudinal slot during
relative pivoting of said members.
Description
BACKGROUND OF THE INVENTION
This invention is in the field of orthopedic leg braces and relates
particularly to the pivot joint at the knee of the brace.
Persons needing and using orthopedic leg braces usually do not have
sufficient muscular control and strength to hold the leg straight
and rigid in supporting the weight of the user on that leg
particularly while walking. Efforts have been made heretofore to
provide a leg brace wherein a pivoted knee joint locks against
pivotal movement when the weight of the user is placed on that leg.
However, such devices have been quite complicated in structure and
in many cases not truly reliable. Those of complicated structure
were subject to malfunction and excessive wear in addition to being
relatively expensive to produce.
SUMMARY OF THE INVENTION
The present invention is a pivot joint for an orthopedic leg brace
of extremely simple construction since it involves essentially no
relatively movable parts other than the two leg members that are
pivotally joined. The joint provides for both pivotal and relative
sliding movement between the upper and lower leg members such that
when the user's leg is lifted, as in walking, the weight of the
lower leg portion causes the two members to slide relative to each
other and the lower leg portion becomes pendulously pivotal
relative to the upper portion. When the upper and lower leg members
are nearly in alignment and the weight of the user is placed on
that leg, the upper leg member slides downwardly relative to the
lower member a small amount and interengaging means on the two
members lock the members against pivotal movement, thus ensuring
that the user's leg will not collapse or fold when weight is placed
thereon. Means are also provided to urge the leg members apart when
weight is relieved therefrom to ensure a return to a freely pivotal
condition and one form of the invention provides a further safety
feature whereby in the event the user loses balance or
inadvertently places weight on his or her braced leg while the knee
is bent, limited sliding movement between the members takes place
to lock the brace against further pivotal movement and thus prevent
the user's falling by collapse of his or her bent leg.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of an orthopedic leg brace
embodying the present invention;
FIG. 2 is a side elevational view of the device of FIG. 1 with
certain parts broken away;
FIG. 3 is a side view, on an enlarged scale, of one of the joints
employed in the brace of FIG. 1 and with parts thereof broken
away;
FIG. 4 is a vertical sectional view taken along the line 4--4 of
FIG. 3;
FIG. 5 is a view similar to FIG. 3 but showing the parts in
different relative positions; and
FIG. 6 is a view similar to FIG. 5 of a modified form of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, the leg brace shown comprises laterally
spaced upper leg members 2 and 4 adapted to extend along the thigh
portion of a user's leg. Each leg member comprises an upper bar 6
and a lower bar 8 each being provided with a plurality of openings
10 whereby the bar members may be longitudinally adjusted and held
in longitudinally adjusted position by suitable fasteners 12 to
adjust the device to the length desired for a particular user. An
upper band structure 14 is secured to the upper bar members 6 and
is provided with straps 16 and buckles 18 whereby it may be secured
to the upper thigh of the user. As shown, a further cradle pad 20
is secured to the upper leg members to assist in holding the device
in fixed relation to the user's thigh. At their lower ends the bar
members 8 are pivotally and slidably joined to lower leg members 22
by pivot joints 24 which will be further described in greater
detail. The lower leg members 22 comprise upper bar members 26 and
lower bar members 28 adjustably secured together in the same manner
as described with reference to the upper leg bar members 6 and 8 to
be adjustable to accommodate the particular length of leg found on
the user. At their lower ends the lower leg members 22 are
pivotally joined, at pivot joint 30, to a clamp device 32 usually
fixed to a special shoe which is customarily part of the apparatus.
The pivot joint 30 corresponds to the user's ankle and the lower
leg member 22 has fixed thereto an encircling clamp pad device 32,
also supplied with straps and buckles similar to the upper pad
member 14. The structure thus far described may be considered more
or less conventional, the novelty residing in the pivot joints 24
which will now be described in greater detail. As shown, there is a
pivot joint 24 on each of the inner and outer leg bar members but
since each pivot joint is similar to the other, being merely a
mirror image thereof, a detailed description of one will
suffice.
Referring now to FIGS. 3 to 5, the upper leg bar member 8 has
secured thereto a bracket structure 36 in the form of a yoke having
spaced side plates 38. The lower leg bar member 26 has a bracket
structure 40 fixed to its upper end and defining a single
plate-like member 42 slidably received between the side plates 38
of the upper bracket 36. The plate 42 is provided with an elongated
slot 55 therein, which slot extends in the direction of the length
of the lower leg member, as clearly shown in the drawings. A
transverse pin 46 extends through the spaced plates 38 and extends
slidably through the slot 55. Preferably, the pin 46, and other
transverse pins to be described later, are loosely positioned in
aligned openings in the plates 38 and normally held therein by a
cover member 48 having side plates 50 lying against the outer
surfaces of the plates 38 and a front web portion 52. The cover
member 48 is secured to the upper bracket 36 by screws 54 but may
be readily removed when access to the inner mechanism is
desired.
A further transverse pin or detent 56 extends between the plates 38
and the periphery of the bracket plate 42 is formed to define an
arcuate edge portion 58, a generally straight edge portion 60 and a
semi-circular socket or notch 62 at the upper end of a lateral
enlargement 64. When the lower leg member is drawn downwardly by
gravity or the like, the slot 44 slides downwardly over pin 46
until the lower leg member hangs on the pin 46 by the upper end of
slot 44 and the parts are then in the position of FIG. 5. When the
pin 46 is thus at the upper end of slot 44, the further pin 56
clears both the surface 60 and the arcuate edge surface 58 and the
upper and lower leg members may freely pivot relative to each
other, as is clearly evident from FIG. 5. With the parts in the
relative positions shown in FIG. 5, assume that the upper leg is
dropped to more nearly vertical position, as in walking, the lower
leg portion, being pendulous, will remain generally upright and the
pin or detent 56 will appear to move to the left, as seen in FIG.
5, over the straight edge surface 60. Under these conditions, if
the weight of the user is placed on the leg having the brace, the
upper leg portion will tend to slide downwardly on the lower leg
portion with pin 46 moving downwardly in slot 44. The pin 56 will
then engage surface 60 and tend to forcibly swing the upper and
lower leg members into longitudinal alignment with the pin 56
sliding downwardly on surface 60 until it seats in the semicircular
slot 62, as shown in FIG. 3. Under these conditions, it is apparent
that the leg members are locked against pivotal movement. When the
user's weight is lifted slightly, a compression spring 66 in a bore
68 of extension 64 acts on a headed plunger 70 to project its pin
portion 72 upwardly into socket 62 and thus ensure that the pin 56
is lifted out of the socket to assist in causing longitudinal
movement of the parts toward a free pivoting position. The socket
62 is preferably at least a full semi-circular socket and thus
tends to grip the pin 66 snugly and gravity alone acting on the
lower leg members and the user's lower leg might not be sufficient
to unseat the pin 56 from socket 62. The bore 68 is closed at its
lower end by a threaded plug member 74 against which the spring 66
reacts and which plug may be adjusted to regulate the force exerted
by spring 66. Obviously, the spring 66 may be easily compressed
when the weight of the user is placed on the braced leg but is
sufficiently strong to ensure unseating of the pin 56.
It will be obvious from FIG. 5 that when the parts are in the
position shown in that figure, the upper leg portion may be swung
more nearly horizontal and the lower leg portion can freely and
pendulously pivot about the pin 46, the pin 56 merely swinging
downwardly spaced a slight distance from the arcuate surface
58.
To further ensure locking of the leg brace when the members are
substantially in alignment at least one of the spaced plates 38 is
provided with an arcuate slot 76 concentric to the pin 46 and
extending throughout about the angular range shown in the drawings.
A third pin 78 extends through the plate 42 and slidably projects
into slot 76 but is quite loose therein, being of a diameter
somewhat less than the width of the arcuate slot 76. When the parts
are in the relative position of FIG. 5, it is apparent that the leg
members may freely pivot about the axis of pin 46 with the pin 78
merely sliding along the slot 76, the ends of the latter, however,
serving as stops to limit the relative pivotal movement of the leg
members. The slot 76, at one end, is provided with a generally
radially extending slot portion 80 extending generally radial to
the pin 46. When the user's leg is substantially straight, as shown
in FIG. 3, and the weight of the user is not on the leg having the
brace, the pin 78 will remain adjacent or on the bottom edge of the
slot 76 and pin 56 will be spaced above the socket 62. However,
when the weight of the user is placed on that leg, the upper leg
portion moves downwardly relative to the lower leg portion to the
locked position of FIG. 3 wherein the pin 56 is seated in socket 62
and the end portion 80 of slot 76 moves downwardly to embrace the
pin 78 and thus serve as a further lock against pivotal movement of
the parts. In this condition, all three pins, 46, 56 and 78, serve
to key the upper and lower leg members against pivotal movement.
The direction of extent of the end portion 80 of slot 76 assists
the surface 60 in directing the parts to the locked position shown
in FIG. 3.
The spaced plates 38 and the plate 42 therebetween are provided
with further openings which are in axial alignment when the parts
are in the position of FIG. 3, those aligned openings being
identified in FIG. 3 by the numeral 82. Such openings perform no
function in the described operation of the device but are provided
so that the user may selectively position a locking pin in those
aligned openings to thus convert the leg brace to a single rigid
brace, incapable of pivotal movement at any time. Thus, the user
may selectively employ the described leg brace as a pivoted brace
that is self-locking when the user's weight is thereon or as a
rigid brace extending throughout the length of the leg.
FIG. 6 illustrates a further embodiment of the invention wherein
the parts are all identical to those described with reference to
FIGS. 3-5 except for the following differences:
Whereas the pin 56 of FIGS. 3-5 may be loosely contained in
openings in the plates 38, the corresponding pin 84 of FIG. 6 is
rigidly fixed in the plates 38 against pivotal movement therein and
it is formed to define a detent nose portion 86. The arcuate
surface 58 of FIGS. 3-5 is shown therein as a smooth edge surface
whereas the corresponding edge of FIG. 6 is provided with detent or
ratchet teeth 88. In normal use of the brace of FIG. 6, the detent
nose 86 is spaced outwardly from the teeth 88 so that the parts do
not engage or interfere with each other during normal pivotal
movement of the parts. However, if the user's leg is in such
position that the parts are pivoted to the relative position shown
in FIG. 6 and if the user loses his or her balance or for some
other reason places weight on the braced leg, the looseness of pin
78 in the slot 76 permits sufficient downward movement of the upper
leg portion relative to the lower leg portion to bring the detent
nose 86 into engagement with one of the teeth 88 and thus lock the
pivot joint against further pivotal movement in a direction which
could result in complete collapse of the user's leg and his falling
to the ground. Thus, the brace structure supports the user until
his or her balance can be regained.
While the proper operation of the present invention depends in part
upon the described sliding of the parts, it must be remembered that
a person's leg is not of rigidly fixed length, the knee and ankle
joints permit enough shortening and lengthening movement to provide
the necessary relatively small movements for the described device
to operate properly.
Although a limited number of specific embodiments of the invention
have been shown, the same are merely illustrative of the principles
involved and other embodiments may be resorted to. For example, the
basic principles of the invention may be practiced by eliminating
the arcuate slot 76 and pin 78, particularly where the user has
considerable strength in his leg.
* * * * *