Caterpillar Tractor Co.

Gerald D Hall

Allyn J Hein

John R Cryder

Lloyd D Swayze

Samuel G Dunlap, Jr

An axially oriented variable displacemnt pistoned device adaptable for use as motor and having a pivoted swash plate angularly positionable for establishing displacement of the device is fitted with externally mounted low pressure hydraulic actuators operably connected with the swash plate for operation thereof. Adjustable stops are provided in the device body to limit travel of the swash plate under urging of the low pressure hydraulic actuators.

Two position variable displacement motor

A hydraulic motor and control system therefor which includes a pump for delivering fluid to a control valve, the control valve having a Float position which connects a first end of the motor to a sump, a First position for applying fluid from the pump to power the motor in a first direction by delivering fluid to the first end of the motor via a flow path and a Second position in which the motor moves in a second and opposite direction. A conduit connects the control valve to the sump. A check valve is provided in the flow path which always allows flow therethrough towards the first end of the motor and normally blocks reverse flow therethrough and also a mechanism for opening the check valve to allow reverse flow therethrough responsive to operation of the control valve in the Float position and in the Second position.

Load check with mechanical venting means

A loader vehicle includes a loading implement movable to a dump and a rack-back position by means of actuation of cylinders. The movement of the cylinders is provided by fluid control valves in turn operated by means which provide for both a slow dump and a fast dump movement of the implement, with fast dump movement initially selected being automatically changed to slow dump movement dependent on the position of the implement.

Implement circuit for motor with slow and fast dump

A flow responsive poppet relief valve includes a housing having an outlet chamber and an inlet passage opening thereon to define an annular valve seat therebetween, a spool disposed for axial movement in the housing and having a head with a conical nose portion thereon, a spring disposed intermediate the housing and the spool for biasing the conical nose portion axially closably against the valve seat and whereby the spool is axially openly moved away therefrom by a fluid in the inlet passage at a predetermined pressure, and an outwardly flared surface portion on the head for assuring that upon opening movement of the spool a relatively thin fluid stream is guided by the conical nose portion in axially relatively low force-transmitting impinging relation glancingly against the flared surface portion, and upon further opening movement of the spool a relatively thicker fluid stream is guided by the conical nose portion in axially relatively greater force-transmitting impinging relation against the flared surface portion, with the streams being deflectably diverted angularly outwardly therefrom to the outlet chamber, in order to assure a stable response and a relatively high degree of pressure regulation of the poppet relief valve.

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Joliet, IL, United States of America

Gerald D Hall