×

Controlled electric pump drive for hydraulic lifting arrangement with gas spring in motor

  • US 4,961,316 A
  • Filed: 10/21/1988
  • Issued: 10/09/1990
  • Est. Priority Date: 10/28/1987
  • Status: Expired due to Term
First Claim
Patent Images

1. A hydraulic lifting arrangement for a lift on a materials-handling vehicle, said arrangement comprising a working piston-cylinder device which includes a cylinder housing having axially movable therein a piston with a hollowed piston head and a hollow piston for raising and lowering the lift assembly, and further comprising a pump assembly which co-acts with a system of pipes for operating the piston-cylinder device, and an electric motor for driving the pump assembly;

  • wherein the piston-cylinder device is a double-acting device having a first and a second working chamber which are isolated sealingly from one another, and includes a tube which extends into the piston head of the piston rod and sealingly delimits a pressure chamber arranged to act as an integrated gas spring for biassing the piston-cylinder device;

    the pump assembly includes a first and a second hydraulic pump of which at least the first pump is a reversible pump, and the pumps are mutually connected in parallel.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×