A prosthetic knee component for an above knee prosthesis having a frame member and a bracket member pivotally connected to the frame member, thereby creating a center of rotation for the knee component. The knee component further including a gait control unit pivotally positioned between the frame member and the bracket member by flanges extending from a rear portion of the bracket member. A flexion bumper is positioned through the frame member away from the center of rotation and is sufficiently compressible in a flexion phase of the knee component to provide controlled energy absorbing compliance under force exerted on the bumper by the rear flanges. The knee component further includes an optional running gait flexion limiter positioned on an interior surface of the frame member for limiting flexion and providing inertia to the lower leg component during a running gait. The running gait flexion limiter provides inertia to the lower leg component by being sufficiently resilient in a flexion phase of the knee component to provide a controlled spring rate to the flanges on the bracket member to quickly return the lower leg component to an extension phase.

A fluid cushioning apparatus acting as a pivoting medium of two objects having a pivoting feature includes a sleeve, a shaft and a partitioning piece. The shaft has two radially enlarged annulations being closely and rotatably mounted in the sleeve and a dividing wall being axially and radially extended between the two annulations to closely engage with the interior wall of the sleeve. The sleeve is mounted on a first object and the shaft is mounted on a second object which is always to have a pivoting relationship with the first object. The partitioning piece is capable of being closely fitted among the sleeve, the shaft and the two annulations and is secured on the sleeve so that the space formed between the shaft and the sleeve is divided into two compartments. The shaft is a hollow member one end of which is mounted a replenishing cushioning fluid supplier while the other end of which is mounted a check valve and a first hole is provided on the shaft so that the liquid supplier will supply the space with new cushioning fluid through the check valve and the first hole when there is a fluid loss in the space. The shaft is further provided with a second hole to let the fluid contained in one of the two compartments flow through the first and second holes to the other one compartment when the first and second object are in relative pivoting movement to obtain a neat cushioning effect.

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.

An artificial leg includes a knee mechanism having means for restricting knee flexing movement during the stance phase of the walking cycle. The restricting means includes a piston and cylinder assembly so coupled in the mechanism that the piston is movable in the cylinder with knee flexion and extension. The knee mechanism includes two chassis parts arranged to move relatively to each other when an axial load is applied to the limb. One end of the piston and cylinder assembly is connected to one of the chassis parts while the other chassis part engages a control member coupled to a valve inside the piston and cylinder assembly so that the valve is operated in response to relative load-dependent movements of the chassis parts in order to restrict the flow of fluid and thereby create resistance to knee flexion during the stance phase. The chassis parts are connected together by an anterior pivot joint and are resiliently moveable relative to each other according to applied load. The piston and cylinder assembly is also operable to resist movement during the swing phase of the walking cycle, and the interaction of the knee chassis parts with the control member is arranged so that movement of the member is reduced or does not occur at all for flexion angles greater than a predetermined value between 30.degree. and 40.degree..

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. An annular seal engages an inner portion of the piston rod and prevents the continuous higher hydraulic static pressure in the displacement chamber from transferring to the operating chamber and the annular seal between the housing and the outer portion of the piston rod.