Abstract: An open center type control valve for a hydraulic motor, wherein pressure fluid from a source is caused to flow from the valve inlet to a motor port at a substantially uniformly metered rate despite fluctuations in the load on the governed fluid motor, due to the operation of a flow control mechanism which regulates bypass of excess fluid through the open center passage to the valve outlet in accordance with variations in the pressure differential between the inlet and outlet end portions of the open center passage.

Abstract: A source fluid supply and pressure control system for hydraulic motors, comprising a motor control valve having valve instrumentalities to govern pressure at its inlet and at its motor ports, and to also limit the supply of source fluid to the inlet in accordance with demand.

Abstract: A spool type control valve mechanism for use with backhoes, front end loaders, and other apparatus having a number of hydraulic cylinder driven work performing members whose motions must be coordinated in order to produce a prescribed work operation. Pressure compensating valve means which provides for regulation of the rate of flow to the cylinders of pressure fluid from a common supply passage also functions automatically to control connection of the cylinders with the supply passage in accordance with the work load on the cylinders, at times when the valve spools of all the control valves are in their working positions.

Abstract: A pressure reducing valve mechanism maintains pressure in one of the service passages of a control valve at a desirably low value except at times when the control valve element is actuated to a position effecting flow of pressurized supply fluid to said service passage for delivery to a motor governed by the control valve.