Pressure responsive hydraulic control circuit
AssigneeCaterpillar Inc.
InventorJerry J. Burckhartzmeyer
Life of this patent
Estimating the term…
Abstract
Backhoes are useful for digging trenches, ditches, etc. However, a performance deficiency caused by the formation of voids in the hydraulic control motor occurs sometimes if the swinging mass of the backhoe is abruptly stopped by quickly moving the directional control valve to the neutral position. The present invention provides a control circuit having a charging valve for communicating pressurized fluid from the supply conduit connected to the pump to charge the makeup valves with pump discharge fluid to minimize or avoid the formation of voids when the directional control valve is moved to the neutral position to stop the swinging movement of the backhoe mechanism.
Claims8
A pressure responsive hydraulic control circuit for controlling a hydraulic motor comprising;
- a directional control valve having an inlet port, an outlet port and a pair of motor ports, said control valve being movable between a neutral position at which the ports are all isolated from one another and an operating position at which the inlet port is in communication with one of the motor ports and the other motor port is in communication with the outlet port;
- a source of variable pressure fluid;
- a supply conduit connecting the source of variable pressure fluid to the inlet port;
- a pair of motor conduits connecting the motor ports with the respective sides of the hydraulic motor;
- a pair of makeup valves connected to the respective motor conduits;
- an exhaust conduit connected to the pair of makeup valves;
- and
- means for communicating pressurized fluid from the supply conduit to the exhaust conduit and super-charging the makeup valves only when the directional control valve is in the neutral position.
A pressure responsive hydraulic control circuit for controlling a hydraulic motor comprising;
- a directional control valve having an inlet port, an outlet port and a pair of motor ports, said control valve being movable between a neutral position at which the ports are all isolated from one another and an operating position at which the inlet port is in communication with one of the motor ports and the other motor port is in communication with the outlet port;
- a source of variable pressure fluid;
- a supply conduit connecting the source of variable pressure fluid to the inlet port;
- a pair of motor conduits connecting the motor ports with the respective sides of the hydraulic motor;
- a pair of makeup valves connected to the respective motor conduits;
- a fluid reservoir;
- an exhaust conduit connected to the pair of makeup valves and being in communication with the fluid reservoir;
- means for communicating pressurized fluid from the supply conduit to the exhaust conduit only when the directional control valve is in the neutral position;
- and
- means for restricting fluid flow through the exhaust conduit to the fluid reservoir so that the makeup valves are super-charged only when the directional control valve is in the neutral position.
Dependencies are inferred from the claim text.