Trench digging vehicle with drive and work motors - has drive motor pump valve responsive to work motor pump pressure and bypass

摘要

A feed transfer mechanism for a trench excavating machine effects the automatic transfer of pressurized fluid from the machine's propulsive motor to the motor actuating working parts and utilizes separate pumps feeding respective motors with a valve in the drive motor feed and a bypass pipe with a non-return valve connecting the two feed pipes. The first valve is controlled by a calibrated spring acting to open the valve and controlled by the pressure prevailing in the working part pump feed, the non-return valve permitting flow in the direction of the working pump part feed.