Hydrostatic transmission

Claim 1

IN A HYDROSTATIC TRANSMISSION, AN AXIAL PISTON PUMP HAVING AN INLET AND AN OUTLET, AN INPUT SHAFT EXTENDING AXIALLY THROUGH SAID PUMP, A VALVE PLATE MOUNTED AGAINST SAID AXIAL PISTON PUMP AND HAVING INLET AND OUTLET PORTS THEREIN, AN AXIAL PISTON MOTOR HAVIONG AN INLET AND AN OUTLET MOUNTED AFJACENT SAID VALVE PLATE, SAID PUMP AND MOTOR INLETS AND OUTLETS COMMUNICATING WITH THE INLET AND OUTLET PORTS ON THE VALVE PLATE TO DEFINE A CLOSED HYDRAULIC CIRCUIT, A MAKEUP PUMP MOUNTED IN SAID VALVE PLATE HAVING AN INLET AND AN OUTLET FOR SUPPLYING MAKEUP FLUID TO THE CIRCUIT CONNECTING THE PISTON PUMP AND MOTOR INCLUDING A ROTATABLE IMPELLER WHEEL HAVING RESILIENTLY FLEXIBLE BLADES CAPABLE OF DEVELOPING A PREDETERMINED PRESSURE IN SAID CIRCUIT AND YIELDING AT PRESSURES IN EXCESS OF THE PREDETERMINED PRESSURE TO THEREBY LIMIT THE PRESSURE OF MAKEUP FLUID TO A PREDETERMINED VALUE, SAID IMPELLER BEING CONNECTED TO SAID INPUT SHAFT, CONDUIT MEANS LEADING FROM THE MAKEUP PUMP TO THE CIRCUIT CONNECTING THE PISTON PUMP AND MOTOR, A VALVE MEMBER IN SAID CONDUIT MEANS CONTROLLING COMMUNICATION BETWEEN THE MAKEUP PUMP SAND SAID FLUID CIRCUIT AND RESPONSIVE TO PRESSURE IN THE HIGHER PRESSURE PORT CONNECTING THE PISTON PUMP AND MOTOR, AND VALVING ON SAID VALVE MEMBER FOR CONNECTING THE LOWER PRESSURE PORT TO SAID MAKEUP PUMP OUTLET.