Caterpillar Inc.

Randall L Mooberry

James D Rinaldo

Jose M Salazar-Vior

Daniel J Schartman

John H Hill

Jeffery A Crosser

A brake assembly, having a plurality of co-operating rotating and non-rotating brake discs, includes a dump valve mechanism, including a spool valve. The spool valve is adapted to move between first and second positions to close and open fluid communications between a fluid supply passage and a fluid dump passage. Excess cooling fluid supplied to a brake assembly when the brakes are inactive causes 'brake drag' which wastes power and decreases machine efficiency. By dumping the cooling fluid to a fluid dump passage when the brakes are inactive, the 'brake drag' is reduced.

Brake assembly having a dump valve

Cushioned swing circuits sometimes have a restricted passage between the motor conduits to allow the implement controlled by the swing circuit to coast to a stop. However, opening and closing of the restricted passage was manually controlled, thereby requiring an additional manipulative step by the operator. The present cushioned swing circuit includes a cushion valve moveable to an open position to establish communication through vent line means when a pressure differential greater than a predetermined level is generated in one of the motor conduits connecting a directional control valve to a hydraulic motor. The cushion valve is retained in the open position for a predetermined limited time after the pressure differential drops below the predetermined level so that the inertia generated pressure in the circuit is dissipated through the vent line means. At the end of the predetermined limited time, the cushion valve is moved to the closed position blocking communication through the vent line means whereupon the circuit is hydraulically locked. The cushion valve is moved between the opened and closed positions automatically and requires no additional effort by the operator.

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East Peoria, IL, United States of America

Randall L Mooberry