Construction for pump/motor devices

Claim 1

IN A PUMP/MOTOR DEVICE OF THE AXIAL PISTON TYPE HAVING A BODY INCLUDING MEANS PRESENTING A VALVE SURFACE, AN INLET PORT AND AN OUTLET PORT SPACED THEREFROM ENTERING ON SAID VALVE SURFACE, AND A ROTATABLE BARREL ENGAGING SAID VALVE SURFACE AND CONTAINING RECIPROCABLE PISTONS IN CYLINDERS, SAID CYLINDERS COMMUNICATING SEQUENTIALLY WITH SAID INLET PORT AND SAID OUTLET PORT AT THE END OF SAID BARREL AS SAID BARREL IS ROTATED; A PRECOMPRESSION PORT ENTERING ON SAID VALVE SURFACE AND COMMUNICATING WITH SAID CYLINDERS SEQUENTIALLY AT A POSITION SPACED BETWEEN SAID INLET PORT AND OUTLET PORT, A VALVE, A FLUID PASSAGE IN SAID BODY BETWEEN SAID PRECOMPRESSION PORT AND SAID OUTLET PORT INCLUDING SAID VALVE, AND PRESSURE RESPONSIVE MEANS OPENING SAID VALVE WHEN PRESSURE AT SAID INLET PORT EXCEEDS PRESSURE AT SAID OUTLET PORT, SAID PRECOMPRESSION PORT ENTERING ON SAID VALVE SURFACE AT A POSITION APPROXIMATELY HALF-WAY BETWEEN THE ANGULAR POSITION OF MAXIMUM CYLINDER FLUID VOLUME AND SAID OUTLET PORT, SAID PRECOMPRESSION PORT BEING SPACED FROM SAID OUTLET PORT BY A DISTANCE GREATER THAN THE DIMENSION OF SAID CYLINDER AT THE END OF SAID BARREL.