Caterpillar Tractor Co.

John R Cryder

Lowell R Hall

Stanley B Adams

Gerald D Hall

Edward A Wirtz

James A Thomas

Frederick A Carbaugh

Samuel G Dunlap, Jr

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 hydraulic motor and control system which comprises a pump delivering fluid to a control valve. The control valve has a Float position which connects a first end of the motor to sump, a First position for applying fluid from the pump to power the motor in a first direction by delivering fluid to the motor's first end 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 motor's first end and normally blocks reverse flow therethrough. A mechanism opens the check valve to permit reverse flow therethrough responsive to operation of the control valve in the Float position and in the Second position.

Load check valve cylinder mounted

A pre-adjusted control module comprises a bracket assembly adapted for attachment to a support structure of a construction vehicle. A control lever is pivotally mounted within the bracket assembly along with a bellcrank having a roller mounted on a first arm thereof. The roller is adapted to selectively engage either one of two notches formed on a lower end of the control lever and is biased in that direction by a tension coil spring connected between the bracket assembly and a second arm of the bellcrank. A control rod is reciprocally mounted in the bracket assembly and has its first end pivotally connected to the control lever and is adapted to have its second end connected to a self-centering valve spool of a directional control valve. A preadjusted sensing means, including a compression coil spring, is connected between the bracket assembly and the control rod to alert the operator upon approach of one of the two detent positions of the control lever, as effected by engagement of the roller with one of the two notches formed on the control lever.

Pre-adjusted control module for construction vehicles

In an improved method and apparatus for harvesting a tree, the pressure exerted on the tree by a grapple assembly is at a first preselected value during shearing of the tree trunk and positioning the severed tree for further processing. The pressure exerted on the tree by the grapple assembly is thereafter reduced to a second preselected value and the tree is further processed.

Apparatus for harvesting a tree

A hydraulic control system having a plurality of hydraulic motors is provided with a sequencing control means for sequentially controlling or operating the motors from a single selector valve. The selector valve is operative to direct pilot fluid through a sequential controlling valve for pilot operation of separate pilot-operated control valves for the separate motors. The sequential control valve is operative to direct the fluid for operation of one of the control valves first for full operation of the first motor and then for directing pilot fluid to the second valve for operating the second motor. For operating the motors in the reverse direction, the second control valve is operative to control the second motor to its fully retracted position and then the first control valve becomes operative until the first motor is fully retracted.

Growing community of inventors

Joliet, IL, United States of America

John R Cryder