Abstract: Variable discharge and energy recovery is produced by an adjustable spool in fluid communication with the outlet chamber for adjustably providing pressurized fluid from the outlet chamber to selected portions of the demeshing area of the intermeshing teeth to vary the discharge flow of the pump and the amount of energy recovery. This results in maintaining a positive pressure in selected portions of the demeshing area as well as equalizing the pressure in the selected areas to the pressure in the outlet chamber.

Abstract: A flow control and load check valve in a spool valve between a first power core (20) and the motor ports (22,24,26) for controlling the flow therebetween as a function of the differential pressure of the first power core and the inlet pressure. A piston (66) responsive to said two pressure positions a sleeve (76) to determine the flow rate. The sleeve (76) also serves as a load check.

Abstract: A hydraulic control system having a supply of low pressure hydraulic fluid and a hydraulic pump having a fluid inlet and a fluid outlet through which fluid is delivered at a high operating pressure when the pump is pumping at its capacity. A valve is placed in fluid communication with the supply of hydraulic fluid and the pump fluid inlet for permitting fluid communication between the supply of hydraulic fluid and the pump fluid inlet when in one mode of operation and for substantially preventing fluid communication between the supply of hydraulic fluid and the pump fluid when in a second mode of operation. A control means prevents the valve from assuming its second mode of operation until the magnitude of the pressure at the pump fluid outlet is below a predetermined pressure. The predetermined pressure is set to be substantially below the pump operating pressure.

Abstract: A mechanical detent for engaging a valve spool having a linear element wire spring positioned transverse to the valve spool for engaging circumferential grooves in the spool. The linear element spring includes a single wire spring having a triangular or square shape, or alternatively, one or more non-integral straight wire springs. Extensions of the linear element spring extend a distance away from the spool that is greater than the spring wire diameter. The extensions allow the spring to be movable out of the groove, while still permitting a small diameter spring wire.