| 摘要 |
<p>A prosthetic leg (10) has a pivotal knee joint (18) and a hydraulic fluid control unit (20) connected to provide variable forces which dampen flexion and extension of the knee and also bias the leg tc its extended position. The unit includes an aluminum housing (22) lined with an axially adjustable sleeve (48) and control bushing (55) defining a cylindrical operating chamber (85) which receives a piston (70) mounted on a tubular piston rod (28). The housing and operating chamber receive hydraulic fluid or oil which flows during movement of the piston through fluid control ports (60), channels (62) and adjustable gaps (98) defined by the sleeve and bushing for damping the movement of the rod. The piston rod encloses a gas filled flexible bladder (140) which forms an oil accumulator during inward movement of the piston rod into a displacement chamber (42) and also produces variable forces for moving the piston rod outwardly to its extended position. An annular seal (66) engages an inner portion of the piston rod and prevents the higher hydraulic pressure in the displacement chamber from transferring to the operating chamber and the annular seal (121) between the housing and the outer portion of the piston rod. <IMAGE></p> |
