| abstract |
A lower limb prosthesis 10 comprises a foot component 12 and an ankle unit 16 pivotally mounted to the foot component 12. The ankle unit 16 comprises an ankle joint mechanism 18 comprising a hydraulic piston and cylinder assembly for providing hydraulic damping whenever the ankle joint flexes at pivot 26, and a vacuum mechanism 20 comprising a pneumatic piston (94, see figure 2) and cylinder assembly 106 for generating a vacuum. The pneumatic piston and cylinder assembly generates a vacuum in chamber 106D during plantar-flexion of the ankle unit 16 (see figure 11), which is transferred via fluid line 40a, 40c to socket 36 through one-way valves 42a. Valve 42b allows fluid to exit the system during dorsi-flexion. The system ensures that suction at the socket connection of the stump to the prosthesis is increased during swing phase of the gait cycle. |