Power plants – Pressure fluid source and motor – Condition responsive control of or by input to input pump...
Patent
1995-01-26
1997-07-22
Nguyen, Hoang
Power plants
Pressure fluid source and motor
Condition responsive control of or by input to input pump...
60477, F16D 3102
Patent
active
056494220
ABSTRACT:
A hydraulic lift apparatus for a battery driven lift truck includes a hydraulic lift cylinder. A hydraulic pump operates as a pump in a load raising mode, so as to feed pressure fluid to the lift cylinder. The hydraulic pump operates as a motor in a load lowering mode. The hydraulic pump is driven by the pressure fluid displaced by the lift cylinder. A direct current machine is coupled to the hydraulic pump, so as to operate as an electric motor in the load raising mode and to operate as a generator in the load lowering mode. A useful brake circuit is energized by the direct current machine in the load lowering mode. A valve assembly is disposed in the pressure fluid path between the lift cylinder and the hydraulic pump. Control apparatus are provided for controlling the valve assembly and including speed regulating apparatus for varying the speed of the direct current machine. At least one secondary hydraulic consumer is adapted to be connected to a hydraulic pressure source via an associated control valve. A lowering branch is provided between the valve assembly and a connection is provided between a check valve and the inlet of the hydraulic pump. The secondary hydraulic consumer receives fluid from the hydraulic pump via the valve assembly. There is provided an externally excited direct current machine having its speed controlled by the speed regulating apparatus in response to operation of the valve assembly.
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Baginski Ralf
Claussen Hans-Peter
Doss Hans-Joachim
Klatt Andreas
Jungheinrich Aktiengesellschaft
Nguyen Hoang
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