Abstract: An articulated knee brace includes a pair of arms pivotally connected by corresponding pivot pins and gear segments supported by a set of hub plates having holes for receiving adjustable stop pins. The arms are attached by flexible and releasable bands to a person's limb on opposite sides of a joint, and one of the arms carries an adjustable hydraulic control unit. The unit includes a tubular housing enclosing a pair of axially spaced pistons rigidly connected by a shaft, and a curved link member connects the pistons to the hub plates eccentrically of the pivot axes. A set of manually rotatable valves are supported by the housing between the pistons and variably control the flow of hydraulic fluid through the valves and between the piston chambers in response to pivoting of the arms for selectively and independently adjusting the resistance to flexion and extension of the brace and limb.

Abstract: A prosthetic leg has a pivotal knee joint and a hydraulic fluid control unit connected to provide variable forces which dampen flexion and extension of the knee and also bias the leg to its extended position. The unit includes an aluminum housing lined with an axially adjustable sleeve and control bushing defining a cylindrical operating chamber which receives a piston mounted on a tubular piston rod. The housing and operating chamber receive hydraulic fluid or oil which flows during movement of the piston through fluid control ports, channels and adjustable gaps defined by the sleeve and bushing for damping the movement of the rod. The piston rod encloses a preferably sealed gas pressurized flexible bladder which forms an oil accumulator during inward movement of the piston rod into a displacement chamber and also produces variable forces for moving the piston rod outwardly to its extended position.

Abstract: A prosthetic leg has a pivotal knee joint and a hydraulic fluid control unit connected to provide variable forces which dampen flexion and extension of the knee and also bias the leg to its extended position. The unit includes an aluminum housing lined with an axially adjustable sleeve and control bushing defining a cylindrical chamber which receives a piston mounted on a tubular piston rod. The housing and chamber receive hydraulic fluid or oil which flows during movement of the piston through fluid control ports, channel and adjustable gaps defined by the sleeve and bushing for damping the movement of the rod. The piston rod encloses a gas filled flexible bladder which forms an oil accumulator during inward movement of the piston rod and also produces variable forces for moving the piston rod outwardly to its extended position. The housing confines a gap defining ring which compensates for changes in oil viscosity with heat.