ARTIFICIAL HYDRAULIC ANKLE JOINT

• US 3,871,032 A
• Filed: 04/04/1974
• Issued: 03/18/1975
• Est. Priority Date: 03/08/1974
• Status: Expired due to Term

• Current Assignee: Wolfgang Karas
• Original Assignee: Wolfgang Karas
• Inventors: Karas, Wolfgang
• Primary Examiner(s): Frinks, Ronald L.
• Application Number:
  US05/458,049
• Time in Patent Office: 348 Days
• Field of Search: 3/1.2,30-35
• US Class Current: 623/26
• CPC Class Codes: A61F 2/6607 Ankle joints
• CPC Class Codes: A61F 2/74 fluid , i.e. hydraulic or pneumatic
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers

Abstract

An artificial ankle joint with an articulate connection between the foot part and the lower leg part of an artificial leg. A damping device comprising at least two hydraulic cylinders connected by conduits and each provided with a piston is hinged to the foot part and the lower leg part, respectively. The pistons have hollow chambers filled with storage oil and pressure-balancing channels lead to the upper end of the hollow chambers. Between the pressure chambers of the hydraulic cylinder and the hollow chamber of the piston a snifting valve is provided which sucks hydraulic liquid from the hollow piston chamber.

Claims

1. An artificial ankle joint comprising a foot part and a lower leg part, an articulate connection arranged therebetween and a damping device hinged, on the one hand to the foot part and, on the other hand to the lower leg part, which damping device comprises at least two hydraulic cylinders with pressure chambers connection conduits connecting the hydraulic cylinders hollow pistons having a bottom part and an upper end and hollow chambers filled with storage oil pressure-balancing channels in contact with the surrounding atmosphere and guided as far as the upper end of the hollow chambers a spring-loaded snifting valve arranged between the pressure chamber of each hydraulic cylinder and the hollow chamber of each piston.

2. The artificial ankle joint set forth in claim 1, wherein the spring-loaded snifting valve is arranged in the bottom part of the piston.

3. The artificial ankle joint set forth in claim 1, wherein the lower leg part is provided with two rollers of equal diameter arranged symmetrically in relation to the articulate connection, which rollers are connected by means of a tension spring with the pistons of two equally dimensioned hydraulic cylinders arranged parallel, the pistons being held in contact with the rollers by means of the tension springs.

4. The artificial ankle joint set forth in claim 3, wherein the pistons are supported by means of a tappet on the rollers the tappets having roll-off surfaces acting against the roller surfaces.

5. The artificial ankle joint set forth in claim 1, wherein in the connection conduits of the cylinders throttle valves with obstacles for ensuring a permanently turbulent flow are installed.