Power plants – Pressure fluid source and motor – Condition responsive control of pump or motor displacement
Reexamination Certificate
2005-12-29
2008-10-07
Lazo, Thomas E (Department: 3745)
Power plants
Pressure fluid source and motor
Condition responsive control of pump or motor displacement
C060S452000
Reexamination Certificate
active
07430859
ABSTRACT:
A fluid pump control system for excavators enables fluid pumps to produce hydraulic flows of a quantity great enough to actuate hydraulic actuators for smooth composite operations. The system includes variable displacement fluid pumps, fluid quantity control mechanisms for controlling the discharge quantity of the respective fluid pumps, fluid quantity control signal lines respectively connected to the fluid quantity control mechanisms, signal pressure control lines for bringing the fluid quantity control signal lines into connection with a fluid tank to drop the fluid quantity control signal pressures within the fluid quantity control signal lines, and a plurality of cutoff valves attached to the signal pressure control lines in tandem and shiftable in concert with the shifting movement of spools of a control valve for increasing the fluid quantity control signal pressures within the signal pressure control lines in proportion to the shifting amounts of the cutoff valves.
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Jang Dal Sik
Jung Ki Nam
Doosan Infracore Co., ltd.
Lazo Thomas E
Lee Hong Degerman Kang & Schmadeka
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