Patent ID: 8740991

Claim:
A prosthetic foot and ankle assembly comprising a combination of: a foot component, and an ankle joint mounted to the foot component and having a fixed range of dorsi-plantar flexion during walking, the ankle joint comprising a joint mechanism providing resistance to ankle flexion, wherein the joint mechanism comprises: a hydraulic linear piston and cylinder assembly having a piston which is movable so as to define a pair of variable-volume chambers, one chamber located on each side of the piston and which is constructed and arranged to provide hydraulic damping continuously over the range of dorsi-plantar flexion, and a valve arrangement controlling the flow of hydraulic fluid between said chambers, the valve arrangement comprising first and second adjustable valves respectively comprising first and second orifices each adjustable in area for independently presetting dorsi-flexion damping resistance and plantar-flexion damping resistance respectively such that during walking said first orifice is preset to provide hydraulic damping at a first setting whenever the ankle joint is flexed in a dorsi-flexion direction and said second orifice is preset to provide hydraulic damping at a second setting whenever the ankle joint is flexed in a plantar-flexion direction, wherein the joint mechanism includes a first flexion limiter that limits dorsi-flexion of the joint mechanism to a dorsi-flexion limit and a second flexion limiter that limits plantar-flexion of the joint mechanism to a plantar-flexion limit, thereby defining said fixed range of dorsi-plantar flexion, the first and second flexion limiters comprising mechanical abutments of the joint mechanism.