Abstract: A hydraulic swing phase control unit for an artificial lower limb including a thigh part and a shin part connected at a knee joint, includes a hydraulic cylinder connected to one of the thigh part and the shin part, a piston movable in the hydraulic cylinder and connected to the other of the thigh part and the shin part, a fluid passage positioned to pass hydraulic fluid pressurized by movement of the piston in the hydraulic cylinder; and a variable sharp edged orifice at the fluid passage. The variable orifice is formed from a sharp edged orifice and a manually rotatable sleeve positioned to at least partly overlap the orifice. At least one low restriction fluid passage in the cylinder is fluidically connected in parallel with the variable sharp edged orifice to permit minimal resistance to movement of the piston during a portion of the movement thereof.

Abstract: A knee mechanism for a lower limb prosthesis which maintains knee stability over an initial range of flexion and includes an upper member for connection to or forming part of the thigh component of a prosthesis, a lower member for connection to or forming part of the shin component of a prosthesis, and a slider and a crank connecting the upper member to the lower member. The locus of the instantaneous center of rotation of the mechanism is a curve which commences above the knee and posterior to the load line and which, over an initial range of flexion of the mechanism, moves continuously downwards and to the posterior, the curve being convex towards the posterior. The lower member, the slider and the crank preferably constitute a slider crank mechanism with the crank pivotally connected to the upper and lower members and the slider pivotally connected to the lower member and slidably connected to the upper member.

Abstract: A hydraulic system including a variable-delivery pump and a pressure compensator having a spring load applied to one end of the compensator spool. Means are provided for applying a force to the other end of the compensator spool proportional to the pressure obtained from a variable pressure-dividing system connected between the pressure line and tank. This pressure dividing system may consist of a pair of restrictors at least one of which is adjustable. Alternatively, it may consist of a spring-loaded check valve between the pressure line and the compensator chamber and a restrictor from the compensator chamber to tank.