Abstract: A pressure compensated pump which supplies fluid to a common header has an automatic pressure compensator adjustment mechanism which adjusts the pressure setting of the pressure compensator in response to changes in the displacement of the pump, such that the compensator pressure setting of the pump is reduced when the displacement of the pump increases to increase pump flow and the pressure setting is increased when the displacement of the pump decreases to reduce pump flow.

Abstract: A control arrangement is provided for controlling the operation of an hydraulic assist turbocharger of the type including an hydraulic turbine driven by an hydraulic fluid under pressure to supplementally drive a turbocharger during engine operating conditions when supplemental air flow is required. The control arrangement includes a dual function control valve responsive to engine speed and load to regulate the supply of hydraulic fluid to the hydraulic turbine in accordance with engine air flow requirements.

Abstract: A hydraulic fluid feeding device for a power steering device is proposed which has a plurality of pumps for feeding hydraulic fluid to the power steering device and a flow path change-over valve for switching the paths between the pumps and the power steering device, wherein the feeding rate of the hydraulic fluid to the power steering device is controlled by the action of the flow path change-over valve. The flow path change-over valve is operated according to the magnitude of the load exerted on the power steering device so that hydraulic fluid from all the pumps combined is fed to the power steering device when the load is great, and the hydraulic fluid from at least one of the pumps is fed to the power steering device when the load is small. With this device, the control of the feeding rate becomes efficient. It also becomes possible to bypass the hydraulic fluid from some of the pumps to a tank, independently of the delivery rates of the pumps, so that the power consumption may be reduced.

Abstract: A drive system for construction machinery in which hydraulic circuit is provided with a plurality of variable-displacement hydraulic pumps and a plurality of hydraulic actuators, each pump being connected in closed circuit to one or a plurality of the actuators via a solenoid-operated valve or valves to drive a movable member or members connected to the actuator or respective actuators when pressurized fluid is supplied to the actuator or actuators from the pump. At least one of the selected hydraulic actuators is further connected in closed circuit through a solenoid-operated valve to at least one of the hydraulic pumps other than the hydraulic pump which is connected in closed circuit to the hydraulic actuator. The hydraulic circuit means is controlled such that timing for switching the solenoid-operated valves is controlled in conjunction with the operation of the pump so as to absorb the shock which would otherwise be produced when each actuator is rendered operative and inoperative.

Abstract: An improved arrangement for operating a hydraulic hammer at a distance from the hydraulic supply. The hydraulic hammer which can be used for breaking rocks, concrete, and the like is disposed at the end of a movable boom, remote from its pressurized hydraulic supply. The hammer is connected to the pressurized hydraulic supply by flexible lines and is movable with respect to the pressurized supply. Disposed in series in the pressurized hydraulic supply line is a hydraulic motor. The hydraulic motor is mounted in close proximity to the hydraulic hammer at the end of the boom. The outlet port of the hydraulic motor connects to the inlet port of the hydraulic hammer. The hydraulic motor drives a suction pump which is also located at the end of the positionable boom. The hydraulic motor and the suction pump are movable with a mounting assembly which supports the hydraulic hammer at the end of the boom. The suction inlet of the hydraulic pump is directly connected to the outlet port of the hydraulic hammer.

Abstract: Hydraulic system for operation of winches which are associated with powered friction pulleys for hauling a wire, the winch winding the wire onto the drum being provided with valves permitting the friction pulleys to idle freely when it is convenient to use the winch drum proper also for hauling the wire.

Abstract: A hydrostatic drive system for connecting a prime mover and a hydraulically operable load such as a hydraulic motor connected to the vehicular wheel has a constant-displacement pump and a variable-displacement pump both connected to the prime mover. The variable-displacement pump is completely reversible and is of maximum displacement substantially greater than the constant displacement pump. This variable-displacement pump is permanently connected across the hydraulic motor of the load. A clutch connects the constant-displacement pump to the same shaft as the variable-displacement pump. The outputs of the constant-displacement pump may be connected by a valve either in parallel to the outputs of the variable-displacement pump, or may simply connect them together for operation of the load only by the variable-displacement pump.

Abstract: A valve device having a pressure operable valve piston, particularly for booster steering systems, to selectively control pressure flow to a consumer device such as a hydraulic servomotor in order to permit use of a reserve pump in event of failure of a main pump. The valve in a neutral position blocks the output of both pumps to a sump but is responsive to a first increase in flow rate beyond a predetermined limit to shunt flow from the reserve pump to a sump. Upon further increase in flow rate the valve piston moves to a position to also shunt part of the output from the main pump to a sump. Differential pressure acting on a valve piston effects shifting and means are provided to vary the differential pressure required to shift the valve piston so that a greater differential pressure is needed for the shifting of the valve piston for the partial shunting of the main pump output. Signal means is actuated by movement of the valve piston to apprise a vehicle driver that the valve device is operative.

Abstract: Flow sensing and control apparatus is provided to selectively combine the fluid output of an auxiliary pump with a hydraulic system. The apparatus includes a valve body having a primary pump passage therein through which fluid from one of a pair of primary pumps is conducted to its respective inlet of a control valve, an auxiliary pump passage interconnected between the auxiliary pump and the primary pump passage and a fluid receiving passage which is connected to the auxiliary pump passage. A pilot operated valve is disposed within the fluid receiving passage and operative in response to fluid flow through the primary pump passage for selectively controlling fluid to the fluid receiving passage so as to permit the combining of any available fluid from the auxiliary pump with that of the primary pump up to a predetermined minimum flow rate through the primary pump passage and for diverting any excess fluid from the auxiliary pump to the receiving passage above that necessary to maintain the minimum flow rate.