Single axis knee joint assembly

• US 6,673,117 B1
• Filed: 11/28/2001
• Issued: 01/06/2004
• Est. Priority Date: 11/30/2000
• Status: Expired due to Fees

• Current Assignee: Adam Soss, David F. Ackley
• Original Assignee: Adam Soss, David F. Ackley
• Inventors: Ackley, David F., Soss, Adam
• Primary Examiner(s): Willse, David H.
• Assistant Examiner(s): Blanco, Javier G.
• Application Number:
  US10/002,099
• Time in Patent Office: 769 Days
• Field of Search: 623/24-27, 623/32-37, 623/39, 623/40, 623/42-46
• US Class Current: 623/24
• CPC Class Codes: A61F 2/64 Knee joints
• CPC Class Codes: A61F 2/644 of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2/72 Bioelectric control, e.g. myoelectric
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2/741 using powered actuators, e.g. stepper motors or solenoids
• CPC Class Codes: A61F 2/748 Valve systems
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers for implantable joints A61F2002/30563
• CPC Class Codes: A61F 2002/503 for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2002/5032 for adjusting fluid pressure
• CPC Class Codes: A61F 2002/5033 for adjusting damping damping means A61F2002/5003
• CPC Class Codes: A61F 2002/5075 Multiple spring systems including two or more helical springs
• CPC Class Codes: A61F 2002/607 Lower legs
• CPC Class Codes: A61F 2002/704 computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2002/7635 for measuring force, pressure or mechanical tension
• CPC Class Codes: F16F 9/5123 responsive to the static or steady-state load on the damper

Abstract

A prosthetic leg having a knee joint assembly that includes a plunger-activated, three-chamber cylinder body, a control valve, a control valve actuator, a pylon shaft and artificial foot. The knee joint assembly rotates in a single axis and provides two-stage hydraulic gait control and shock absorption relative to two spring-biased pistons. A cam linkage and actuator valve having a moveable piston and piston chamber responds to knee flexion and switches fluid flow at the control valve and cylinder between a “soft” spring and a “hard” spring to provide two levels of adjustable control to stabilize the user. Alternative microprocessor directed electronic and hydraulic controllers are also disclosed that can be adapted to a knee assembly to sense myoelectric activity and rotation, strain, and/or linear movement of the prosthesis.

Claims

1. A prosthetic knee comprising:

a) an axle and first and second yokes and wherein said first and second yokes are coupled to rotate relative to one another and at least one of said first and second yokes is coupled to rotate about said axle;

b) a hydraulic cylinder having first, second and third chambers mounted to one of said first and second yokes, wherein said first and second chambers include first and second springs mounted to bias first and second pistons to resist fluid flow directed against said first and second pistons by a plunger piston mounted in said third chamber and coupled to said axle;

c) a control valve body having a fluid flow channel coupled to said hydraulic cylinder and including a control member mounted in a fluid path to said hydraulic cylinder to divert fluid flow from said third chamber to a selected one of said first and second chambers to resist movement of said plunger piston; and

d) an actuator coupled to said control valve body and responsive to external forces applied to one of said first and second yokes for manipulating said control member relative to external forces experienced by said knee.

2. A prosthetic knee as set forth in claim 1 including a cam mounted to one of said first and second yokes and a push rod mounted to the other of said first and second yokes and wherein said push rod is coupled to said actuator.

3. A prosthetic knee as set forth in claim 2 wherein said actuator comprises first and second pieces displaced from one another and mounted for reciprocating linear motion relative to one another in opposition to longitudinal forces experienced by said first and second yokes, wherein one of said first and second pieces contains an actuator piston, and wherein when one of said first and second yokes rotates a predetermined angular displacement, said push rod directs said actuator piston to manipulate said control member.

4. A prosthetic knee as set forth in claim 2 in combination with means coupled to one of said first and second yokes for mounting to a leg stump, wherein a prosthetic foot and a pylon are coupled to the other of said first and second yokes, wherein said actuator is coupled to said pylon and comprises an actuator body that includes an actuator piston, and wherein said push rod is coupled to said actuator body to induce said actuator piston to direct fluid to manipulate said control member.

5. A prosthetic knee as set forth in claim 4 wherein said actuator comprises first and second pieces displaced from one another and mounted for reciprocating linear motion relative to one another in opposition to longitudinal forces directed from said foot to said pylon and to said first and second yokes, wherein said actuator piston is mounted in a piston chamber in a cylinder of said actuator body, and wherein when one of said first and second yokes rotates a predetermined angular displacement, said push rod directs said actuator piston to manipulate said control member.

6. A prosthetic knee as set forth in claim 1 wherein said first and second springs exhibit different spring constants.

7. A prosthetic knee as set forth in claim 6 including means for adjusting the compression of at least one of said first and second springs.

8. A prosthetic knee as set forth in claim 7 wherein said control valve body includes a needle valve in said fluid flow channel for selectively controlling fluid flow therethrough.

9. A prosthetic knee as set forth in claim 1 wherein said actuator comprises an actuator body that includes an actuator piston, wherein a pylon is mounted to said actuator body to permit reciprocating movement relative to said actuator piston and such that when one of said first and second yokes rotates a predetermined angular displacement, said pylon directs said actuator piston to manipulate said control member.

10. A prosthetic knee as set forth in claim 1 wherein said actuator includes a servo and means for sensing myo-electric signals at a leg stump and means responsive to said myo-electric signals for directing said servo to manipulate said control member.

11. A prosthetic knee as set forth in claim 1 wherein said actuator includes a servo and means for sensing rotational movement at said knee and responsively coupling drive signals to said servo to manipulate said control member.

12. A prosthetic knee as set forth in claim 1 wherein said actuator includes a servo and means for sensing linear movement at said knee and responsively coupling drive signals to said servo to manipulate said control member.

13. A prosthetic knee as set forth in claim 1 wherein said actuator comprises an actuator body, a pylon mounted to said actuator body and a prosthetic foot coupled to said pylon and wherein said actuator includes a servo and means for sensing strain at said pylon and responsively coupling drive signals to said servo to manipulate said control member.

14. A prosthetic knee comprising:

a) an axle and first and second yokes and wherein said first and second yokes are coupled to rotate about said axle;

b) a hydraulic cylinder having first, second and third chambers mounted to one of said first and second yokes, wherein said first and second chambers include first and second springs mounted to bias first and second pistons to resist fluid flow directed against said first and second pistons by a plunger piston coupled to said axle and mounted in said third chamber;

c) a control valve body having a fluid flow channel coupled to said hydraulic cylinder and including a control member mounted in a fluid path to said hydraulic cylinder to divert fluid flow from said third chamber to a selected one of said first and second chambers to resist movement of said plunger piston;

d) an actuator coupled to said control valve body and responsive to external forces applied to said first and second yokes for manipulating said control member relative said external forces and comprising first and second pieces displaced from one another and mounted for reciprocating motion relative to one another; and

e) a cam mounted to one of said first and second yokes and a linkage coupling said cam to said actuator, such that when one of said first and second yokes rotates a predetermined angular displacement said linkage directs said actuator to manipulate said control member.

15. A prosthetic knee as set forth in claim 14 in combination with means coupled to one of said first and second yokes for mounting to a leg stump, wherein a prosthetic foot and a pylon are coupled to the other of said first and second yokes, wherein said actuator is coupled to said pylon and comprises an actuator body that includes an actuator piston, and wherein said cam is mounted to a push rod linkage coupled to said actuator piston.

16. A prosthetic knee as set forth in claim 14 wherein said first and second springs exhibit different spring constants.

17. A prosthetic knee as set forth in claim 14 including means for adjusting the compression of at least one of said first and second springs.

18. A prosthetic knee as set forth in claim 14 wherein said control valve body includes a needle valve in said fluid flow channel for selectively varying the dimensions of said flow channel.

19. A prosthetic leg comprising:

a) a prosthetic knee including,

1) an axle and first and second yokes and wherein said first and second yokes are coupled to rotate about said axle;

2) a hydraulic cylinder having first, second and third chambers mounted to one of said first and second yokes, wherein said first and second chambers include first and second springs mounted to bias first and second pistons to resist fluid flow directed against said first and second pistons by a plunger piston coupled to said axle and mounted in said third chamber;

3) a control valve body coupled to said hydraulic cylinder and including a control member mounted in a fluid path between said hydraulic cylinder and said control valve body for diverting fluid flow from said third cylinder to a selected one of said first and second chambers to resist movement of said plunger piston;

4) an actuator coupled to said control valve body and responsive to external forces applied to said first and second yokes for manipulating said control member relative said external forces and comprising first and second pieces displaced from one another and mounted to accommodate reciprocating motion relative to one another and wherein one of said pieces includes an actuator piston; and

5) a cam mounted to one of said first and second yokes and a linkage responsive to movement of said cam coupled to said actuator, and wherein when said first and second yokes rotate to a predetermined relative angular relationship and when a predetermined displacement condition exists between said first and second actuator pieces said linkage directs movement of said actuator piston and thereby movement of said control member;

b) means coupled to one of said first and second yokes for mounting to a leg stump; and

c) a prosthetic foot and a pylon coupled to said prosthetic foot and to said actuator.

20. A prosthetic knee as set forth in claim 19 wherein said first and second springs exhibit different spring constants.