Vickers, Inc.

Sperry Corporation

Sperry Rand Corporation

Henry D Taylor

Robert H Breeden

Vinod K Nanda

Robert G Farrell

A hydraulic control system comprising a hydraulic actuator having opposed openings adapted to alternately function as inlets and outlets for moving the element of the actuator in opposite directions and a variable displacement pump with loading sensing control for supplying fluid to said actuator. A pilot pressure operated meter-in valve is provided to which the fluid from the pump is supplied and pilot pressure is applied to the meter-in valve for controlling the direction and displacement of movement of the meter-in valve and the direction and velocity of the actuator. A pair of lines extends from the meter-in valve to the respective openings of the actuator and a pilot pressure operated meter-out valve is associated with each line of the actuator for controlling the flow out of the actuator when that line to the actuator does not have pressure from from the pump applied thereto. A spring loaded poppet valve is associated with each line and a passage extends from at least one of the poppet valves to the meter-out valve and operable, when the meter-out valve is closed after being open, to reduce the pressure holding the spring loaded poppet valve closed, thereby permitting the spring loaded poppet valve to open at a relatively low pressure developed in one of the lines associated with the one meter-out valve, thereby allowing the one meter-out valve to open.

Power transmission

A hydraulic control system comprising a hydraulic actuator having opposed openings adapted to alternately function as inlets and outlets for moving the element of the actuator in opposite directions, a pump for supplying fluid to said actuator, pilot operated meter-in valve to which the fluid from the pump is supplied for controlling the direction of movement of the actuator, and pilot operated meter-out valve associated with at least one opening of the actuator for controlling the flow out of said actuator. The pressure of fluid being supplied to the actuator by the meter-in valve means is sensed and caused to produce a force opposing the movement of the meter-in valve means by the pilot pressure and also applied to a device for controlling an overhauling load resulting in a smooth and accurate control of the movement of the actuator.

A hydraulic system for synchronizing telescoping sections of a crane boom comprising a fixed section and second, third and fourth sections that can be extended and retracted, hydraulic cylinders between the sections for extending and retracting the adjacent sections relative to one another and a control valve for each cylinder. Cables are provided between the sections such that a non-uniformity in movement of the sections causes a change in displacement of the cables which is sensed by position sensing devices to provide a hydraulic pilot signal for modifying flow of hydraulic fluid to the cylinders.

A hydraulic system for controlling hydraulic motors for driving a tracked vehicle which circuit utilizes a single manual control lever to control valve control units to direct pilot pressure to actuate bi-directional valves that control the direction of movement of the hydraulic motors.

Hydraulic steering system for full-track vehicles

A multifunction hydraulic flow metering valve and a circuit therefore comprising a main valve, a bleed flow orifice, and a servo valve acting with the main valve provides for proportional speed control for lowering loads and as an anti-cavitation check valve. A pilot valve in the circuit acting with the main valve provides the circuit with a pressure limiting relief valve.

A hydraulic pressure relief circuit including a main valve, a bleed flow orifice to provide stability to the main valve, a pilot valve having a differential area piston and a damping orifice in conjunction with an accumulator chamber. System pressure is limited by opening the main valve and allowing fluid flow from the system back to tank. The main valve is controlled as a bleed flow servo wherein the pilot valve meters the bleed flow from the bleed flow orifice to tank thereby controlling the opening of the main valve. Fluid flow through the damping orifice in conjunction with the accumulator chamber acts on the pilot valve to provide damping forces acting on the pilot valve with both rising and falling system pressures thereby limiting the maximum rate of pressure increase in the circuit.

A hydraulic control system comprising a hydraulic actuator having opposed openings adapted to alternately function as inlets and outlets for moving the element of the actuator in opposite directions and a variable displacement pump with loading sensing control for supplying fluid to said actuator. A meter-in valve is provided to which the fluid from the pump is supplied and a pilot controller alternately supplies fluid at pilot pressure to the meter-in valve for controlling the direction and displacement of movement of the meter-in valve and the direction and velocity of the actuator. A pair of lines extends from the meter-in valve to the respective openings of the actuator and a meter-out valve is associated with each line of the actuator for controlling the flow out of the actuator when that line to the actuator does not have pressure fluid from the pump applied thereto. Each meter-out valve is pilot operated by the pilot pressure from the controller.

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Pontiac, MI, United States of America

Henry D Taylor