Hydraulic control system
AssigneeGeneral Signal Corporation
InventorRobert C. Westveer
Life of this patent
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Abstract
A hydraulic control system for regulating the distribution of fluid from a variable displacement pump to a plurality of fluid actuated devices is disclosed. The control system includes at least first and second control valves, each of which valves regulates the flow of fluid to a fluid actuated device. Each of the first and second control valves includes, respectively, a first means for developing a first pressure signal and a second means for developing a second pressure signal. A selector means senses the first and second pressure signals and transmits a control pressure signal which is the smaller of the two pressure signals to a fluid actuated displacement control means which regulates the displacement of the pump in response to the magnitude of the control pressure signal.
Claims17
A hydraulic control system, comprising:
- a fluid reservoir;
- a variable displacement pump having a fluid input in fluid communication with said fluid reservoir and a fluid output;
- a first control valve having a fluid input in fluid communication with said fluid output of said variable displacement pump, said first control valve being adapted to regulate a flow of fluid to a first fluid actuated device and including first means for developing a first pressure signal;
- at least a second control valve having a fluid input also in fluid communication with said fluid output of said variable displacement pump, said second control valve also being adapted to regulate a flow of fluid to a second fluid actuated device and including second means for developing a second pressure signal;
- selector means for sensing individually said first and second pressure signals and for providing a control pressure signal which is the smaller of said first and second pressure signals and which is independent of the load placed on said first or second control valves by said first or second fluid actuated devices;
- and
- fluid actuated displacement control means, which control means is in fluid communication with said selector means, for sensing said control pressure signal provided by said selector means and for regulating the displacement of said pump in response to the magnitude of said control pressure signal.
A hydraulic control system comprising:
- a fluid reservoir;
- a variable displacement pump having a fluid input in fluid communication with said fluid reservoir and a fluid output;
- a first control valve having a fluid input in fluid communication with said fluid output of said variable displacement pump and a fluid output, said first control valve being adapted to regulate a flow of fluid to a first fluid actuated device and including first means for developing a first pressure signal indicative of the demand of said first control valve;
- flow control means having a fluid input in fluid communication with said input of said first control valve for developing a second pressure signal independent of the demand of said first control valve at a fluid output;
- at least a second control valve having a fluid input in said fluid communication with said fluid output of said first control valve and said flow control means, said second control valve being adapted to regulate a flow of fluid to a second fluid actuated device and including second means for developing a third pressure signal indicative of said first and second pressure signals and the demand of said second control valve;
- fluid actuated displacement control means for sensing said third pressure signal and for regulating the displacement of said pump in response to the magnitude of said third pressure signal;
- and
- wherein said second pressure signal in combination with said first pressure signal as input to said displacement control means through said second control device prevents said pump from going maximum displacement in response to said first pressure signal when said third pressure signal does not include a demand component of said second control device.
Dependencies are inferred from the claim text.