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A hydraulic lifting arrangement for a lift assembly on a materials-handling vehicle includes a working piston-cylinder device (17) for raising and lowering the lift assembly, a reversible pump assembly (40) for operating the piston-cylinder device, and an electric motor for driving the pump assembly

A hydraulic lifting arrangement for a lift assembly on a materials-handling vehicle includes a working piston-cylinder device (17) for raising and lowering the lift assembly, a reversible pump assembly (40) for operating the piston-cylinder device, and an electric motor for driving the pump assembly. The piston-cylinder device (17) is a double-acting device and has two working chambers (28,29), which are connected to the pump assembly by connecting pipes (46,47). The pump assembly comprises a first and a second hydraulic pump (41,42) having fixed displacements. The pumps are so arranged in the system that together they supply hydraulic medium to and receive hydraulic medium from solely the first chamber (28) whereas only the pump motor (41) supplies and receives hydraulic medium to and from the second chamber (29). The relationship between the displacement of the first pump (41) and the sum of the displacements of both pumps (41,42) corresponds essentially to the relationship between the respective active piston areas in the second and the first chambers. Conveniently, a pressure-gas chamber (26) is arranged in the piston-cylinder device for biassing the piston (19) so as to enable the dead weight of the lift assembly and a given part of the load to be counter-balanced.

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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 assembl

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.