Abstract: A prosthetic ankle and foot combination has an ankle joint mechanism constructed to allow damped rotational movement of a foot component relative to a shin component. The mechanism provides a continuous hydraulically damped range of ankle motion during walking with dynamically variable damping resistances, and with independent variation of damping resistances in the plantarflexion and dorsiflexion directions. An electronic control system coupled to the ankle joint mechanism includes at least one sensor for generating signals indicative of a kinetic or kinematic parameter of locomotion and/or walking environment, the mechanism and the control system being arranged such that the damping resistances effective over the range of motion of the ankle are adapted automatically in response to such signals. Single and dual piston hydraulic damping arrangements are disclosed, including arrangements allowing independent heel-height adjustment.

Abstract: A prosthetic knee joint mechanism has an hydraulic load-activated knee-stabilizing device for resisting joint flexion. A rotary piston (34) connected to one part of the mechanism is rotatable within a fluid-filled fluid displacement chamber (18) associated with another part of the mechanism to drive fluid through a fluid passage which contains a main valve (38) which restricts or allows joint flexion according to the position of a valve member within the valve. The valve member is movable towards an open position in response to fluid pressure in the fluid passage upstream of the valve member caused by application of a flexion torque to the knee joint mechanism, movement of the valve member in the direction of the open position being at least resisted by a valve control arrangement actuated by application of the wearer's weight. The weight-responsive valve control arrangement is preferably a weight-responsive pilot valve (32) for hydraulically resisting movement of the valve member of the main valve.

Abstract: A prosthetic ankle and foot combination has an ankle joint mechanism constructed to allow damped rotational movement of a foot component relative to a shin component. The mechanism provides a continuous hydraulically damped range of ankle motion during walking with dynamically variable damping resistances, and with independent variation of damping resistances in the plantarflexion and dorsiflexion directions. An electronic control system coupled to the ankle joint mechanism includes at least one sensor for generating signals indicative of a kinetic or kinematic parameter of locomotion, the mechanism and the control system being arranged such that the damping resistances effective over the range of motion of the ankle are adapted automatically in response to such signals. Single and dual piston hydraulic damping arrangements are disclosed, including arrangements allowing independent heel-height adjustment.

Abstract: An hydraulic heel-height adjustment device for a lower limb prosthesis has a foot-mounting component (18) for detachably mounting a prosthetic foot and a shin component pivotally connected to the foot-mounting component allowing angular adjustment of the foot-mounting component relative to the shin component about a heel-height adjustment axis. The relative angular position is set by an hydraulic piston (42) and cylinder assembly which has a chamber (40) in the shin component containing a piston (42) arranged to execute a translational movement in the chamber when adjustment is required. A bypass passage interconnects parts of the chamber on opposite sides of the piston, this passage containing a manually operable valve which is spring-biased towards a closed position. The piston has a piston rod pivotally connected to the foot-mounting component by a pivot joint defining a medial-lateral axis parallel to and spaced from the heel-height adjustment axis.

Abstract: A self-aligning prosthetic foot and ankle assembly has an ankle unit pivotally mounting a foot component. The ankle unit contains a hydraulic piston and cylinder assembly having a piston which is linearly movable within a cylinder. The axis of the cylinder is coincident with a shin axis defined by a shin connection interface on the ankle unit. Bypass passages containing damping resistance control valves provide continuous hydraulic damping of dorsi and plantar ankle flexion, the unit being such that, over the major part of the range of damped movement, there is no resilient biasing in either the dorsi or the plantar direction. This confers a number of advantages, including stabilisation of standing, balance control, and improved stair-walking and ramp-walking.

Abstract: A lower limb prosthesis for an above-knee amputee has an adaptive control system which includes a knee flexion control device arranged to resist flexion at the knee joint both hydraulically and pneumatically by means of a dual piston and cylinder assembly. Sensors arranged to sense knee bending moments and knee flexion angle provide electrical signals which are fed to a processing circuit for automatically adjusting the hydraulic and pneumatic resistance to flexion according to the activity mode of the amputee and, when walking, according to the speed of the cylinder containing hydraulic fluid. The hydraulic resistance to flexion predominates during the stance phase and pneumatic resistance predominates during the swing phase. Provision is made for programmable resistance during level walking, walking on an incline, descending stairs and during a stumble.