Abstract: A load responsive fluid power control system using servo type flow control valves and fluid motors supplied by a variable displacement pump. The pump displacement is regulated by a control valve in response to the motor load pressure to vary the pump displacement to maintain a constant preselectable ratio between the pump outlet pressure and motor load pressure and to vary the pressure differential between pump outlet pressure and motor load pressure with variation in magnitude of the load. The pump control also limits maximum and minimum system pressures.

Abstract: A direction flow control valve for control of positive and negative loads equipped with a load responsive positive load control which automatically regulates valve inlet pressure to maintain a relatively constant pressure differential between inlet pressure and load pressure. The load responsive control of the direction flow control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive fluid power multiple load control system using load responsive direction and flow control valves in combination with pump control responding to highest system load. Each direction flow control valve is equipped with a single load responsive controller which automatically regulates fluid flow into and out of the fluid motor to maintain a constant pressure in front of a variable flow controlling orifice, during the control of both positive and negative loads. The load responsive controller of each direction control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive direction and flow control valve for use in fluid power load responsive system. The valve maintains a selected constant flow level for control of both positive and negative loads, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. System is powered by a single fixed or variable volume pump. The direction flow control valve is equipped with a load responsive control which automatically regulates pump discharge pressure to maintain either a constant low pressure level or low pressure differential at the motor exhaust. The pump discharge pressure is either regulated by bypassing of excess flow to reservoir, or by a special load responsive control, which varies the pump displacement. Direction control valve may also be equipped with a control responsive to load pressure for controlling negative loads and an inlet pressure throttling control for simultaneous control of multiplicity of loads.

Abstract: A load responsive fluid power multiple load control system using load responsive direction and flow control valves in combination with pump control responding to highest system load. Each direction flow control valve is equipped with a load responsive pressure control which automatically regulates valve inlet pressure to maintain a constant low pressure level at the motor exhaust and a load responsive negative load control to control a constant pressure differential at the motor exhaust. The load responsive control of each direction control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive fluid power multiple load control system using load responsive direction and flow control valves in combination with pump control responding to highest system load. Each direction flow control valve is equipped with a load responsive pressure control which automatically regulates valve inlet pressure to maintain a constant low pressure level at the motor exhaust and a load responsive negative load control to control a constant pressure differential at the motor exhaust. The load responsive control of each direction control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive direction and flow control valve for use in a fluid power load responsive system. The valve maintains a selected constant flow level for control of both positive and negative loads in parallel or series type circuits, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. When controlling positive or negative loads the valve maintains a constant pressure differential across a flow control metering orifice utilizing a single load responsive controller, first by throttling fluid entering the inlet chamber and then by throttling the fluid leaving the outlet chamber. The load responsive controller blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive direction and flow control valve for use in fluid power load responsive system. The valve maintains a selected constant flow level for control of both positive and negative loads, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. When controlling positive or negative loads the valve maintains a constant pressure differential across a flow control metering orifice utilizing a single control slide member, first by throttling fluid entering the inlet chamber and then by throttling the fluid leaving the outlet chamber. The valve may be used with fixed displacement pumps, fixed displacement pumps equipped with differential pressure relief valves, with variable pumps equipped with pressure compensators and variable pumps equipped with differential pressure compensators.

Abstract: A load responsive fluid power multiple load control system using load responsive direction and flow control valves in combination with pump flow control responding to highest system load. Each direction flow control valve is equipped with a load responsive negative load control. The negative load responsive control of each direction control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust while maintaining a constant pressure in front of a variable flow metering land.

Abstract: A direction flow control valve for control of positive and negative loads equipped with a load responsive control which automatically blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive fluid power multiple load control system using load responsive direction and flow control valves in combination with pump control responding to highest system load. Each direction flow control valve is equipped with a load responsive positive load control which automatically regulates valve inlet pressure to maintain a relatively constant pressure differential between pump inlet pressure and load pressure at a first level and a load responsive negative load control which automatically regulates valve inlet pressure to maintain a relatively constant pressure differential between pump inlet pressure and load pressure at a second higher level. The load responsive control of each direction control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A load responsive fluid power control system using servo type flow control valves and fluid motors supplied by a variable displacement pump. The pump displacement is regulated by a control valve in response to the motor load pressure to vary the pump displacement to maintain a constant preselectable ratio between the pump outlet pressure and motor load pressure and to vary the pressure differential between pump outlet pressure and motor load pressure with variation in magnitude of the load. The pump control also limits maximum and minimum system pressures.

Abstract: A load responsive direction and flow control valve for use in fluid power load responsive system. The system is powered by a single fixed or variable displacement pump. The valve maintains a selected constant flow level during control of positive loads and automatically blocks pump flow to the actuator in presence of a negative load, providing the actuator inlet flow requirement from the valve exhaust manifold. The direction and flow control valve is equipped with a load responsive control which during control of positive load maintains a constant low pressure level at the actuator outlet and retains its control characteristics in a system in which multiple positive loads are simultaneously controlled.

Abstract: A load responsive direction and flow control valve for use in fluid power load responsive system. The valve maintains a selected constant flow level for control of both positive and negative loads, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. When controlling positive or negative loads the valve maintains a constant pressure differential across a flow control metering orifice utilizing a single control slide member, first by throttling fluid entering the inlet chamber and then by throttling the fluid leaving the outlet chamber. The valve may be used with fixed displacement pumps, fixed displacement pumps equipped with differential pressure relief valves, with variable pumps equipped with pressure compensators and variable pumps equipped with differential pressure compensators.

Abstract: A pressure compensated load responsive flow control valve for use in a system controlling a plurality of loads. The system is powered by a single, fixed displacement pump. The flow control valve is equipped with a load responsive control, which during simultaneous control of multiple loads automatically maintains the pump discharge pressure at a level higher than the pressure required by the largest load being controlled. To obtain unidirectional flow, load sensing passages of individual valve spools are connected by check valves with the load responsive control, which is equipped with a leakage control, maintaining a relatively constant leakage from load sensing circuit, irrespective of sensing circuit pressure and permitting fast response of pressure compensated load responsive flow control valve without excessive leakage losses.

Abstract: A load responsive fluid power multiple load control system using load responsive direction and flow control valves in combination with pump control responding to highest system load. Each direction flow control valve is equipped with a load responsive positive load control which automatically regulates valve inlet pressure to maintain a relatively constant pressure differential between pump inlet pressure and load pressure at a first level and a load responsive negative load control which automatically regulates valve inlet pressure to maintain a relatively constant pressure differential between pump inlet pressure and load pressure at a second higher level. The load responsive control of each direction control valve blocks the pump flow to the motor while controlling negative load, providing the motor inlet with fluid from the motor exhaust.

Abstract: A mixed loop hydrostatic transmission circuit for use principally with orbit, gear, vane and other non-piston type motors, which generate contaminants making them less suitable for applications using conventional closed loop hydrostatic transmission circuits. The mixed loop hydrostatic transmission drive retains the precise load control and high efficiency of a closed loop system, while introducing the benefits of contamination control of open loop hydrostatic transmission circuits. While maintaining the speed of the motor proportional to the output flow of the pump, both in positive and regenerative modes of operation, the flow of fluid is diverted from the motor to an injector type inlet booster connected to the reservoir, which supplies the full flow of fluid, required by the pump.

Abstract: A load responsive direction and flow control valve for use in fluid power load responsive system. The valve maintains a selected constant flow level for control of both positive and negative loads, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. System is powered by a single fixed or variable volume pump. The direction flow control valve is equipped with a load responsive control which automatically regulates pump discharge pressure to maintain either a constant low pressure level or low pressure differential at the motor exhaust. The pump discharge pressure is either regulated by bypassing of excess flow to reservoir, or by a special load responsive control, which varies the pump displacement. Direction control valve may also be equipped with a control responsive to load pressure for controlling negative loads and an inlet pressure throttling control for simultaneous control of multiplicity of loads.

Abstract: A load responsive direction and flow control valve for use in fluid power load responsive system. The valve maintains a selected constant flow level for control of both positive and negative loads, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. When controlling positive or negative loads the valve maintains a constant pressure differential across a flow control metering orifice utilizing a single control slide member, first by throttling fluid entering the inlet chamber and then by throttling the fluid leaving the outlet chamber. The valve may be used with fixed displacement pumps, fixed displacement pumps equipped with differential pressure relief valves, with variable displacement pumps equipped with pressure compensators and variable displacement pumps equipped with differential pressure compensators.

Abstract: A direction and flow control valve for use in a central fluid power load responsive system having plurality of loads. The valve maintains a selected constant flow level for control of both positive and negative loads, irrespective of the change in the load magnitude or change in the fluid pressure, supplied to the valve. System is powered by a single variable volume pump equipped with a load responsive control, which automatically maintains pump discharge pressure at a level higher than the pressure required by the system's largest load. Each direction and flow control valve is equipped with a differential pressure regulating control, which is responsive to the load pressure for controlling the negative loads and preferably a second differential pressure regulating control for controlling the positive loads.