Caterpillar Tractor Co.

Leon E Hicks

Wayne A Peterson

Lawrence F Schexnayder

Cyril W Habiger

Robert Casey

John W Grant

Loyal O Watts

A method and plural embodiments of apparatus for delivering a pressure-compensated supply of fluid to a hydraulic steering circuit, wherein first and second pumps are respectively operated by a vehicle engine and by a ground wheel when the vehicle is in motion, output fluid from the two pumps being simultaneously directed to the steering circuit by a control valve with inlet relief valve means modulating output pressure of the sources in response to operation of the control valve. One embodiment contemplates dual inlet relief valves for separately modulating output from the two pumps while another embodiment contemplates one of the pumps having a variable output.

Dual source hydraulic steering system

A fluid drive assembly has a pump, a variable displacement motor, a fluid circuit connecting the pump to the motor, and an actuator device for controlling the displacement of the motor. The actuator device is movable between a first position at which the displacement of the motor is at a preselected maximum and a second position at which the displacement of the motor is at a preselected minimum. A control system for the fluid drive assembly includes a source of fluid at a first preselected pressure value. A valve device is connected to the source of fluid and to the actuator device for controlling the fluid flow therebetween and is movable between a first position at which the source of fluid is in communication with the actuator device and a second position at which the source of fluid is blocked from communication with the actuator device. A first device automatically moves the valve device to the second position in response to the fluid pressure in the fluid circuit exceeding a second preselected pressure level. A second device retains the valve device in the first position until the fluid pressure in the fluid circuit decreases from the second preselected pressure level to a third preselected pressure level.

Control system for a fluid drive

A spline lubricating device comprises a capsule defining a chamber filled with lubricating fluid on one end of a splined shaft. The splined shaft and lubricating capsule is inserted into an internally splined member which contains a centrally disposed slinger, and a plunger mounted in the slinger for engaging the capsule for releasing the fluid from the lubricating capsule with the slinger directing the fluid to the spline teeth.

Capsule lubricator

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.

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Joliet, IL, United States of America

Leon E Hicks