Piston return mechanism

Claim 1

IN AN AXIAL PISTON PUMP OR MOTOR DEVICE, HOUSING MEANS, A ROTATABLE CYLINDER BLOCK IN SAID HOUSING MEANS HAVING A PLURALITY OF AXIAL CYLINDERS AND A CENTRAL RECESS, A DRIVE SHAFT IN SAID RECESS CONNECTED FOR ROTATION WITH THE CYLINDER BLOCK, BEARING MEANS IN SAID HOUSING FOR CONSTRAINING AXIAL MOVEMENT OF SAID SHAFT, A PLURALITY OF PISTONS HAVING ENDS RECIPROCABLE IN SAID CYLINDERS, A CAM PLATE AT ONE END OF SAID CYLINDER BLOCK HAVING A BEARING FACE INCLINED TO THE END OF THE CYLINDER BLOCK, SAID DRIVE SHAFT EXTENDING COMPLETELY THROUGH SAID CYLINDER BLOCK AND SAID CAM PLATE, SAID BEARING MEANS SUPPORTING SAID DRIVE SHAFT IN SAID HOUSING AT BOTH ENDS THEREOF, SECOND BEARING MEANS ON THE OUTER ENDS OF SAID PISTONS ENGAGING SAID CAM PLATE, PORTS COMMUNICATING THE CYLINDERS WITH THE OPPOSITE END OF SAID CYLINDER BLOCK, A PORT MEMBER ADJACENT THE OPPOSITE END OF THE CYLINDER BLOCK, AND SPRING MEANS WHOLLY WITHIN SAID DRIVE SHAFT FOR URGING SAID SECOND BEARING MEANS INTO ENGAGEMENT WITH SAID CAM PLATE.