Hydraulic controller, especially for the movement of a prosthetic joint

Abstract From the Canadian patent

A hydraulic controller for the motion of the prosthetic joint comprises a piston-and-cylinder unit whose working chambers on opposite sides of the piston are connected to each other by a connecting passage and to a compensating chamber which stores a volume of hydraulic fluid to compensate for the difference in the volumes of the cylinder chambers resulting from the fact that the piston rod passes through one of them. Regardless of the direction of movement of the piston in the cylinder, utilizing checkvalves and adjustable throttle elements, the flow is controlled between the chambers so the separate throttle elements can effectively control the opposite movements while checkvalves permit …