U.S. patent application number 10/642220 was filed with the patent office on 2005-02-24 for artificial knee joint with a push rod biased to rotate a prosthetic lower leg rapidly to align with a residual thigh.
Invention is credited to Chen, Chien-Chuan, Chen, Chien-Liang, Chen, I-Chun.
Application Number | 20050043821 10/642220 |
Document ID | / |
Family ID | 34104638 |
Filed Date | 2005-02-24 |
United States Patent
Application |
20050043821 |
Kind Code |
A1 |
Chen, Chien-Liang ; et
al. |
February 24, 2005 |
ARTIFICIAL KNEE JOINT WITH A PUSH ROD BIASED TO ROTATE A PROSTHETIC
LOWER LEG RAPIDLY TO ALIGN WITH A RESIDUAL THIGH
Abstract
An artificial knee joint includes a joint seat, a support frame,
a hydraulic device, a push rod, and a biasing member. The joint
seat has a joint body and a rotatable member connected pivotally to
the joint body and connected fixedly to a residual thigh. The
support frame is connected rotatably to the joint body, and is
connected fixedly to a prosthetic lower leg. The push rod is
movable relative to the joint body between an extended position,
where a free end of the rotatable member is spaced apart from the
joint body to align the lower leg with the thigh, and a retracted
position, where the free end of the rotatable member abuts against
the joint body. The biasing member biases the push rod to the
extended position.
Inventors: |
Chen, Chien-Liang; (Taipei
City, TW) ; Chen, Chien-Chuan; (Taipei City, TW)
; Chen, I-Chun; (Taipei City, TW) |
Correspondence
Address: |
FOLEY AND LARDNER
SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Family ID: |
34104638 |
Appl. No.: |
10/642220 |
Filed: |
August 18, 2003 |
Current U.S.
Class: |
623/44 ;
623/46 |
Current CPC
Class: |
A61F 2002/5075 20130101;
A61F 2002/745 20130101; A61F 2002/503 20130101; A61F 2/646
20130101; A61F 2/644 20130101 |
Class at
Publication: |
623/044 ;
623/046 |
International
Class: |
A61F 002/64 |
Claims
We claim:
1. An artificial knee joint for connecting a residual thigh of a
prosthetic wearer to a prosthetic lower leg, said knee joint
comprising: a joint seat including a joint body and a rotatable
member that is adapted to be connected fixedly to the thigh and
that has a pivot end connected pivotally to said joint body, and a
free end; a hollow support frame having an upper end and a lower
end that is adapted to be connected fixedly to the lower leg; a
connecting unit for connecting said upper end of said support frame
rotatably to said joint body so as to permit rotation of the lower
leg relative to the thigh; a hydraulic device disposed within said
support frame and having a piston rod that is disposed movably in
said support frame and that is connected to said joint body; a push
rod disposed movably within said joint body and movable between an
extended position, where an upper end of said push rod projects
from said joint body and where said free end of said rotatable
member is spaced apart from said joint body to align the lower leg
with the thigh, and a retracted position, where said upper end of
said push rod is retracted into said joint body and where said free
end of said rotatable member abuts against said joint body; and a
biasing member for biasing said push rod to said extended position
so that said free end of said rotatable member turns away from said
joint body, thereby facilitating movement of the lower leg to a
full extension position, where the lower leg is aligned with the
thigh.
2. The artificial knee joint as claimed in claim 1, wherein said
rotatable member is configured generally as a horizontal plate,
said joint body having a top surface that is formed with a vertical
hole, said push rod being disposed within said vertical hole in
said joint body, said biasing member being configured as a coiled
compression spring and being disposed within said vertical hole in
said joint body so as to press said push rod upward against said
free end of said rotatable member.
3. The artificial knee joint as claimed in claim 2, wherein said
joint body further has an adjustment bolt that is disposed in said
vertical hole and immediately under said coiled compression spring
and that is adjustable to change biasing force of said coiled
compression spring.
4. The artificial knee joint as claimed in claim 1, wherein said
connecting unit includes a horizontal pivot pin extending into said
upper end of said support frame and said joint body.
5. The artificial knee joint as claimed in claim 1, wherein said
connecting unit includes four upright links, each of which has an
upper end that is connected pivotally to said joint body, and a
lower end that is connected pivotally to said upper end of said
support frame.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an artificial knee joint, and more
particularly to an artificial knee joint that includes a push rod
biased to rotate a prosthetic lower leg rapidly to align with a
residual thigh.
[0003] 2. Description of the Related Art
[0004] Referring to FIGS. 1 and 2, a conventional artificial knee
joint 200 is shown to include a joint seat 80, two links 81 (only
one is shown), a support frame 82, and a hydraulic device 83. The
joint seat 80 is connected fixedly to a thigh 8 of the prosthesis
wearer, and is connected rotatably to the support frame 82 by the
links 81. The hydraulic device 83 includes a cylinder body 830 that
has upper and lower oil chambers 832, 833, and a piston rod 831
that is connected to the links 81 and that is movable within the
cylinder body 830. The upper and lower oil chambers 832, 833 are in
fluid communication with each other via an oil passage 834. As
such, the hydraulic device 83 can retard relative rotation of the
thigh 8 and the lower leg 9 during extension and flexion of the
artificial knee joint 200.
[0005] When the thigh 8 is raised to flex the joint 200, as shown
in FIG. 1, a coiled compression spring 835 is compressed by the
piston rod 831. Subsequently, when the thigh 8 is turned
frontwardly to align the thigh 8 with the lower leg 9, as shown in
FIG. 2, the coiled compression spring 835 returns to its stretched
state. Although the coiled compression spring 835 can push the
piston rod 831 upwardly so as to bias the thigh 8 to align with the
lower leg 9 during movement of the artificial knee joint 200 from
the flexed position shown in FIG. 1 to the extended position shown
in FIG. 2, the movement of the piston rod 831 is retarded due to
presence of hydraulic liquid within the cylinder body 830 so that
it takes a relatively long time to rotate the lower leg 9 relative
to the thigh 8 from the position shown in FIG. 1 to that shown in
FIG. 2. As such, the lower leg 9 may not be able to align with the
thigh 8 when the lower leg 9 is pressed against the ground by the
thigh 8 during fast walking, thereby resulting in falling of the
prosthesis wearer.
SUMMARY OF THE INVENTION
[0006] The object of this invention is to provide an artificial
knee joint that includes a push rod biased to rotate a prosthetic
lower leg rapidly to align with a residual thigh.
[0007] According to this invention, an artificial knee joint
includes a joint seat, a support frame, a hydraulic device, a push
rod, and a biasing member. The joint seat has a joint body and a
rotatable member connected pivotally to the joint body and
connected fixedly to a residual thigh of a prosthesis wearer. The
support frame is connected rotatably to the joint body, and is
connected fixedly to a prosthetic lower leg. The push rod is
disposed movably within the joint body, and is movable between an
extended position, where the push rod projects from the joint body
and where a free end of the rotatable member is spaced apart from
the joint body to align the lower leg with the thigh, and a
retracted position, where the push rod is retracted into the joint
body and where the free end of the rotatable member abuts against
the joint body. The biasing member biases the push rod to the
extended position so that the free end of the rotatable member
turns away from the joint body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] These and other features and advantages of this invention
will become apparent in the following detailed description of the
preferred embodiments of this invention, with reference to the
accompanying drawings, in which:
[0009] FIG. 1 is a partly sectional, schematic side view of a
conventional artificial knee joint, which is in a flexed state;
[0010] FIG. 2 is a partly sectional, schematic side view of the
conventional artificial knee joint, which is in an extended
state;
[0011] FIG. 3 is a schematic side view of the first preferred
embodiment of an artificial knee joint according to this invention,
which is in a flexed state;
[0012] FIG. 4 is a side view of the first preferred embodiment,
which is in an extended state;
[0013] FIG. 5 is a side view of the first preferred embodiment,
illustrating arrangement of a pushing device;
[0014] FIG. 6 is a schematic rear view of the first preferred
embodiment, illustrating the positions of two pushing units of the
pushing device relative to a piston rod;
[0015] FIG. 7 is a side view of the first preferred embodiment,
illustrating a retracted position of a push rod of one pushing unit
of the pushing device; and
[0016] FIG. 8 is a side view of the second preferred embodiment of
an artificial knee joint according to this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] Before the present invention is described in greater detail
in connection with the preferred embodiments, it should be noted
that similar elements and structures are designated by like
reference numerals throughout the entire disclosure.
[0018] Referring to FIGS. 3, 4, 5, and 6, the first preferred
embodiment of an artificial knee joint according to this invention
is shown to include a joint seat 1, a hollow support frame 2, a
hydraulic device 3, and a pushing device 4 consisting of two
pushing units 40 (see FIG. 6), each of which includes a push rod
41, a biasing member 42, and an adjustment bolt 43.
[0019] The joint seat 1 includes a joint body 11 and a rotatable
member 12 that is adapted to be connected fixedly to a residual
thigh 8 of a prosthesis wearer and that has a pivot end 121
connected pivotally to the joint body 11, and a free end 122. The
rotatable member 12 is configured generally as a horizontal plate.
The support frame 2 has a lower end that is adapted to be connected
fixedly to a prosthetic lower leg 9. A connecting unit includes a
horizontal pivot pin 5 extending into an upper end of the support
frame 2 and the joint body 11 so as to connect the upper end of the
support frame 2 rotatably to the joint body 11 to thereby permit
rotation of the lower leg 9 relative to the thigh 8. The hydraulic
device 3 is disposed within the support frame 2, and has a piston
rod 31 that is disposed movably in the support frame 2 and that is
connected pivotally to a link 6, which is connected pivotally to
the joint body 11. The pushing units 40 are located at two sides of
the piston rod 31, as shown in FIG. 6. Since the pushing units 40
are identical in construction, only one of the pushing units 40
will be described in the succeeding paragraph.
[0020] The push rod 41 is disposed movably within a vertical hole
112 in a top surface of the joint body 11, and is movable between
an extended position shown in FIG. 5, where an upper end of the
push rod 41 projects from the joint body 11 and where the free end
122 of the rotatable member 12 is spaced apart from a rear end of
the joint body 11 to permit the lower leg 9 to align with the thigh
8, and a retracted position shown in FIG. 7, where the upper end of
the push rod 41 is retracted into the joint body 11 and where the
free end 122 of the rotatable member 12 abuts against the rear end
of the joint body 11. The biasing member 42 is configured as a
coiled compression spring, and is disposed within the vertical hole
112 in the joint body 11 so as to press the push rod 41 upward
against the free end 122 of the rotatable member 12. As such, when
no external force is applied to the free end 122 of the rotatable
member 12, the push rod 41 is biased by the biasing member 42 to
its extended position, thereby facilitating movement of the lower
leg 9 to a full extension position, where the lower leg 9 is
aligned with the thigh 8. The adjustment bolt 43 is disposed in the
vertical hole 112 in the joint body 11 and immediately under the
biasing member 42, and is adjustable to change the biasing force of
the biasing member 42.
[0021] When the artificial knee joint is flexed to deflect the
lower leg 9 from the thigh 8, the free end 122 of the rotatable
member 12 turns downward relative to the joint body 11 such that
the push rod 41 is pressed by the free end 122 of the rotatable
member 12 to move from the extended position shown in FIG. 5 to the
retracted position shown in FIG. 7. At this time, the biasing
member 42 is compressed, and is able to provide a restoration force
for returning the push rod 41 to the extended position so as to
rotate the lower leg 9 rapidly to align with the thigh 8 when the
rotatable member 12 is released.
[0022] FIG. 8 shows the second preferred embodiment of an
artificial knee joint according to this invention, which is similar
to the previous preferred embodiment in construction. Unlike the
previous preferred embodiment, the connecting unit includes four
upright links 7 (only two are shown), each of which has an upper
end that is connected pivotally to the joint body 11 in a known
manner, and a lower end that is connected pivotally to the upper
end of the support frame 2 in a known manner.
[0023] With this invention thus explained, it is apparent that
numerous modifications and variations can be made without departing
from the scope and spirit of this invention. It is therefore
intended that this invention be limited only as indicated by the
appended claims.
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