Abstract: A hydraulic power system is disclosed which comprises an internal combustion engine having a speed regulator, and which serves to drive a hydraulic system including a pump and a consumer or load. A throttle valve is positioned in the hydraulic system, and the throttle valve is connected to an adjustable controller, such that the volume flow rate to the consumer is proportional to the control signal delivered to the throttle valve by the controller. The same control signal of the controller is also delivered to the speed regulator of the engine. In one disclosed embodiment, the hydraulic system includes a plurality of consumers connected to a common pump, and each consumer includes an associated throttle valve and controller. Also, means are provided for weighting the several control signals from the controllers, and summing the weighted signals so that a composite adjusting signal is delivered to the speed regulator of the engine.

Abstract: A hydraulic flow control apparatus is provided which is adapted to provide a constant pressure differential between a pump and an external load. The apparatus includes a housing, and a balance piston slideably mounted therein. The pump pressure acts to bias the piston in a direction toward a pump bypass position, and the piston is urged in the other direction and toward its operating position by the consumer pressure and a spring. Means are also provided whereby the pressure of the pump necessary to move the piston toward its bypass position and against the force of the spring, may be minimized during operation in the idling mode, to thereby minimize power consumption.

Abstract: A hydraulic flow control apparatus is provided which is adapted to provide a constant pressure differential between a pump and an external load. the apparatus includes a housing, and a balance piston slideably mounted therein. The pump pressure acts to bias the piston in a direction toward a pump bypass position, and the piston is urged in the other direction and toward its operating position by the consumer pressure and a spring. Means are also provided whereby the pressure of the pump necessary to move the piston toward its bypass position and against the force of the spring, may be minimized during operation in the idling mode, to thereby minimize power consumption.