Abstract: An artificial leg has a femoral member (1); a lower-leg member (2) articulated to the femoral member about a knee joint axis (3') and adapted for connection to a prosthetic foot; and a hydraulic device (4) for controlling the knee joint functions of the artificial leg. The hydraulic device comprises a cylinder member (4a) which is articulated to the lower-leg member, and a piston rod (4b) which is articulated to the femoral member. The hydraulic device (4) is operated by an operating rod (11). The lower-leg member consists of an upper part (2a) which is articulated to the femoral member (1) and supports the hydraulic device (4) whose cylinder member (4a) is articulated to the upper part, and a lower part (2b) which is adapted for connection to the prosthetic foot and to which the operating rod (11) is connected. The upper part (2a) is articulated to the lower part (2b) about a pivot pin (13) located in front of the knee joint axis (3') to which it is parallel, to be pivoted relative to the lower member.

Abstract: A hydraulic device for controlling the knee-joint function in a leg prosthesis has a cylinder which is divided into first and a second cylinder parts adapted to be fixed to the lower leg of the prosthesis, and a piston rod which carries one piston in each cylinder part and is fixed to the upper leg of the prosthesis. The pistons divide the interior of the respective cylinder parts into two chambers. The adjacent first chambers of the cylinder parts are interconnected by a throttle device. The two, second chambers are also interconnected. One piston has a sealing member which is of a single-acting type to allow leakage of hydraulic fluid from the second chamber to the first chamber when the piston is moved in a direction reducing the volume of the second chamber, while it is completely sealing when the piston is moved in the opposite direction. A connection is provided between one of the first chambers and one of the second chambers.

Abstract: A hydraulic device for controlling the knee-joint function in a leg prosthesis has a cylinder which is divided into first and a second cylinder parts adapted to be fixed to the lower leg of the prosthesis, and a piston rod which carries one piston in each cylinder part and is fixed to the upper leg of the prosthesis. The pistons divide the interior of the respective cylinder parts into two chambers. The adjacent first chambers of the cylinder parts are interconnected by a throttle device. The two, second chambers are also interconnected. One piston has a sealing member which is of a single-acting type to allow leakage of hydraulic fluid from the second chamber to the first chamber when the piston is moved in a direction reducing the volume of the second chamber, while it is completely sealing when the piston is moved in the opposite direction. A connection is provided between one of the first chambers and one of the second chambers.