Abstract: A split-discharge balanced dual-lobe vane-type rotary hydraulic machine that comprises a housing, a rotor mounted within the housing and having a plurality of radially extending peripheral slots, and a plurality of vanes individually slidably mounted in the rotor slots. A cam ring within the housing surrounds the rotor and has a radially inwardly directed surface forming a track for sliding engagement with the vane. Opposed symmetrical pressure cavities are formed between the cam ring surface and the rotor, and fluid inlet and outlet passages in the housing are coupled to the fluid pressure cavities. The fluid inlet and outlet passages include a fluid inlet port opening into each cavity adjacent to one circumferential edge thereof, a first fluid outlet port opening into each cavity adjacent to the opposing circumferential edge thereof, and a second fluid outlet port opening into each cavity at a position circumferentially between the inlet and first outlet ports.

Abstract: A cartridge type sleeve and plunger hydraulic valve is retained in a blind bore along with a biasing spring by a closure plug. Spaced transverse passages intersecting the bore are either separated or connected depending upon whether the plunger is either shifted by the spring bias or by fluid pressure overcoming the spring bias. An elastomeric seal eliminates leakage when the valve is in closed position. To insure against accidental fall out of any loose parts when the valve is disassembled under difficult working conditions, as in mines, O-rings are utilized as retainers for the spring and other parts.

Abstract: A speed controller for a rotary pump and motor hydraulic power transmission comprises a pair of pulse generators, one driven at a reference speed and the other proportionally to motor speed. An algebraic summing circuit connects the two pulse generators to the displacement regulator of the hydraulic pump. Error signals produced by the changes in phase of the pulse generators adjust the pump displacement to maintain the motor speed in step with the reference speed.