DOUBLE-ACTING HYDRAULIC PUMP AND AIR MOTOR THEREFOR

摘要

A hydraulic pump and double-acting air motor therefor including means for controlling the inlet and exhaust of air to and from the opposite sides of the piston in the air cylinder. A pilot valve operated by the air piston controls one operating valve for the cylinder and a pilot relay valve. The pilot relay valve controls another operating valve which is in reverse phase with respect to the first-operating valve. The piston-operated pilot valve has a snap action feature so that the pilot valve, the pilot relay valve and the operating valves all reverse condition abruptly with a minimum dwell to provide a smoother power transmission. Also a muffler which inhibits ice formation is operatively associated with the operating valves for muffling the noise of the air being exhausted from the air cylinder through the operating valves with minimal accumulation of ice.