Single axis knee joint assembly

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.

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.