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Hydraulic controller, especially for the movement of a prosthetic joint

  • US 4,958,705 A
  • Filed: 10/28/1988
  • Issued: 09/25/1990
  • Est. Priority Date: 10/30/1987
  • Status: Expired due to Term
First Claim
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1. A hydraulic controller, especially for the movement of a prosthetic joint, comprising:

  • a piston-and-cylinder unit having a cylinder, and a piston displaceable in said cylinder and having a piston rod extending ut of one end of said cylinder, said piston defining within said cylinder and on opposite sides of said piston a first cylinder chamber free from said rod and a second cylinder chamber through which said rod extends, said cylinder chambers communicating with one another;

    a compensation chamber adapted to receive hydraulic fluid from said first chamber in excess of that required by said second chamber upon displacement of said rod into said cylinder and corresponding to a volume of said rod in said second chamber;

    a first check valve communicating between said first chamber and said compensation chamber and oriented to block flow from said first chamber to said compensation chamber but permitting flow from said compensation chamber to said first chamber;

    a bypass connected across said first check valve between said first chamber and said compensation chamber and provided with a first throttle element throttling flow of said fluid therebetween;

    means forming a passage connecting said second chamber with said compensation chamber and provided with a further throttle element for throttling flow of said fluid therebetween; and

    a further check valve connected between at least one of said first and compensation chambers and said second chamber and oriented to block flow of said fluid from said second chamber but permitting flow into said second chamber and filling of said second chamber upon said displacement of said rod, said further check valve being provided in a flow passage communicating between said first and second chambers and connected to said first and second chambers between said throttle elements and first and second said chambers, respectively, said check valves and throttle elements being provided directly in said piston and said rod.

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