Abstract: There is herein disclosed a lift control system for a press unloader having an extendable and retractable jaw means for gripping and removing a part from the die cavity of a press with pivotal frame means supporting the jaw means for pivotal movement to lift the part from the die cavity and interconnected air operated power cylinder means to sequentially extend the jaw means, grip the part, lift the part, and retract the jaw means.

Abstract: A steering shaft, linked with the dirigible wheels of an automotive vehicle and coupled with a hydraulic servomotor for rotation in either direction under the control of a main valve, has two abutments for alternately opening two normally closed ancillary valves in respective limiting positions of the shaft, these ancillary valves being inserted in branches of two feeder lines extending from the main valve to respective cylinder chambers of the servomotor. Either ancillary valve, when opened, connects one cylinder compartment of a differential valve to the feeder line then under low pressure, the other compartment of that differential valve being connected to a supply conduit whereby a pressure difference is created across a spring-loaded piston in that valve whose two compartments are interconnected by a bleeder line. The piston, upon being displaced by this pressure against its spring force, vents the supply conduit to the low-pressure side of the fluid source to arrest the servomotor.

Abstract: A dual hydraulic clutch with two operating positions and an intermediate neutral position receives pressure fluid through a three-position selector valve communicating with a pair of piston cylinders which are alternately under high and low fluid pressure in operation and are both under low pressure in neutral. Shifting the control valve partly unloads one of the cylinders into a throttled discharge line with generation of a pressure drop therein to actuate a bypass valve for instantly lowering the pressure in a supply line; the disappearance of this pressure drop upon termination of shifting gradually recloses the bypass valve for progressively raising the supply pressure to its operating level.

Abstract: A hydraulic brake booster is disclosed for use in a vehicle hydraulic braking system. The booster provides a spool valve having spaced lands and grooves cooperating with corresponding lands and grooves on the booster housing to control communication between an inlet port, an outlet port, an exhaust port, and the booster pressure chamber. The spool valve has an internal passage which communicates the booster pressure chamber to one of the aforementioned ports depending upon the position of the spool valve. A check valve is provided in a branch passage communicating with the groove communicated with the booster inlet port so that the pressure level in the pressure chamber never exceeds the pressure level at the inlet regardless of the position of the spool valve. This feature enhances spool stability.

Abstract: A load limiting hydraulic control system for a hydraulic cylinder adapted to raise or tilt a load including a control valve having an inlet port and a movable valving member adapted to direct pressure flow to said cylinder. A fluid responsive valve is connected to a source of fluid supply and said inlet port. A control circuit is provided connected to the control valve and the fluid responsive valve, and the fluid responsive valve is responsive to the pressure in the control circuit to control the fluid supplied to said control valve. The system incorporates a unique limit valve mechanism connected to the cylinder and the control circuit and is responsive to a predetermined pressure at the cylinder to interrupt the control circuit to reduce the fluid supply and prevent further actuation of the cylinder.

Abstract: Multiple embodiments of a hydraulic control circuit for a double-acting hydraulic motor to provide fluid at a relatively high pressure for operating the motor in a selected direction and otherwise providing operating fluid to the motor at a relatively low pressure, the control circuit including a dual pressure relief valve which is operatively responsive to the motor or an implement positioned by the motor to provide the two operating pressures. An additional dual pressure relief valve regulates the flow of exhaust fluid from one side of the motor to allow controlled response of the motor to external forces. The hydraulic control circuit of the present invention is preferably contemplated for operating a push-pull coupling to permit selective tandem operation of two vehicles.

Abstract: An integral power steering assembly of the type which includes a housing defining a power cavity with a rack-toothed piston movably supported in the cavity and in meshing engagement with a sectored gear which in turn rotates an output shaft. A control valve is supported by the housing for controlling the flow of pressurized fluid from a source to the cavity on one side or another of the piston and the return flow from the opposite side of the piston whereby the piston is moved in alternative and opposite directions. An input shaft forms a part of and controls the control valve. Mechanical connections also interconnect the input shaft and an output shaft for rotating the output shaft in response to rotation of the input shaft in the event of the lack or loss of fluid pressure to move the piston hydraulically. These components are in the form of an integral or unitized package which may be attached to a vehicle as one unit.