Abstract: Solenoid operated directional valves are disclosed which have a modular construction wherein electrical connections between component parts are made integral and concurrent with the act of mounting the component parts together. The modular construction means that no separate lead wires are required to be connected between the component parts. The modular construction: reduces the time required to assemble valves in the factory; facilitates installation and maintenance procedures in the field; permits optional features to be selectively incorporated into or removed from valves in a non-destructive waste-free fashion; and essentially eliminates the possibility of improperly connecting electrical circuits within valves.

Abstract: A solenoid operated directional valve comprises a plug-in type solenoid which makes electrical connection with a terminal block on the valve body via plug-in type terminals. The plug-in type terminals are on a connector element which is selectively positionable on the solenoid to select either a portion of the solenoid winding which is for 60 hertz energizing current or a portion which is for 50 hertz current.

Abstract: A solenoid operated directional valve 10 that has cushioning chambers 48 and 50 into which the attenuation elements 52 and 54 on the ends of the spool 38 are received for cushioning the movement of the spool, and a transfer loop 56 through which fluid can travel during the cushioning operation, characterized in that the attenuation elements are constructed and arranged so that they will function to purge air or other gaseous fluids from the cushioning chambers and the transfer loop as an incident to reciprocal movement of the spool.

Abstract: A solenoid operated directional valve with a valve body provided with a bore that has axially spaced annuli, a mounted surface with ports arranged in a pattern of standard configuration, and ducts extending from the ports to the annuli to provide passageways for flow of fluid, and a spool mounted for movement axially in said bore for controlling flow of fluid through said passageways, the passageways being formed in a unique manner in said body so that a minimum pressure drop occurs in the fluid flowing through each passageway.

Abstract: Control apparatus 24 for use with a pressure-flow compensated variable displacement pump assembly 10 for saving energy by limiting the power output of the pump 12 to the load requirements, or to the pump drive capacity, comprising a pressure regulated variable orifice means 52 through which the pumped fluid to load flows, the orifice means being responsive to changes in pressure of the pumped fluid from the pump assembly to vary inversely the effective area of the orifice means, the flow compensator 28 of the pump assembly functioning to hold the pressure drop across the orifice means constant so that the flow across the orifice means also varies inversely with the pressure to limit to a preselected value the horsepower supplied by the pump assembly to load.

Abstract: A wet plunger type solenoid primarily for use with hydraulic valves adapted for high pressure hydraulic fluid systems, the armature assembly being constructed so that a stainless steel armature tube can be employed to provide a strong plunger chamber that will withstand high pressures of the hydraulic fluid, and the armature tube and the associated yoke and stop pieces at the ends of the plunger chamber are arranged so that the non-magnetic tube does not cause an "air gap" in the magnetic fluid of the solenoid, thereby allowing the solenoid to operate at lower electrical loads and temperatures.

Abstract: Apparatus for assembling a complete modular valve system, including modules containing manifold blocks in which are mounted valves, such as flow controls, checks, pressure reducers and reliefs, the modules being sandwich mounted between a directional valve and a standard subplate for use in conjunction with hydraulic cylinders and the like, and the valves being arranged in the manifold blocks so that multiple-function modules can be provided.

Abstract: Variable differential pressure control apparatus is used in a hydraulic system including a pump, an accumulator for receiving hydraulic fluid under pressure from the pump and for discharging hydraulic fluid to a work device, and an unloading valve in the circuit between the pump and the accumulator for regulating pressure of the fluid to the accumulator. The control apparatus is connected with the unloading valve for opening and closing the latter and is adjustable (1) for selectively setting the maximum fluid pressure to the accumulator and (2) for selectively setting the variation between the maximum pressure to the accumulator, at which pressure the unloading valve will open, and the minimum pressure to the accumulator at which pressure the unloading valve will close for recharging the accumulator.

Abstract: Variable differential pressure control apparatus is used in a hydraulic system including a pump, an accumulator for receiving hydraulic fluid under pressure from the pump and for discharging hydraulic fluid to a work device, and an unloading valve in the circuit between the pump and the accumulator for regulating pressure of the fluid to the accumulator. The control apparatus is connected with the unloading valve for opening and closing the latter and is adjustable (1) for selectively setting the maximum fluid pressure to the accumulator and (2) for selectively setting the variation between the maximum pressure to the accumulator, at which pressure the unloading valve will open, and the minimum pressure to the accumulator at which pressure the unloading valve will close for recharging the accumulator.