Synchronization of fluid power drives

Claim 1

IN A SELF-PROPELLED VEHICLE HAVING A FRAME, AN ENGINE AND DRIVING WHEELS MOUNTED ON SAID FRAME, TRANSMISSION MEANS INTERPOSED BETWEEN SAID DRIVING WHEELS AND SAID ENGINE, SHIFT MEANS ARRANGED TO CHANGE THE DRIVING RATIO OF SAID TRANSMISSION MEANS, MECHANICAL CLUTCH MEANS INTERPOSED BETWEEN SAID TRANSMISSION MEANS AND SAID ENGINE, SAID MECHANICAL CLUTCH MEANS HAVING MECHANICAL ACTIVATING MEANS TO SELECTIVELY DISCONNECT SAID ENGINE FROM SAID TRANSMISSION MEANS, AT LEAST ONE STEERING WHEEL PIVOTALLY MOUNTED ON SAID FRAME, THE COMBINATION THEREWITH OF A FLUID POWER TRANSMISSION AND CONTROL SYSTEM DISPOSED TO DRIVE SAID STEERING WHEELS COMPRISING, FLUID MOTOR MEANS MOUNTED ON SAID STERING WHEELS AND DRIVINGLY ENGAGED THEREWITH, A VARIABLE FLOW PUMP DISPOSED TO DRIVE SAID FLUID MOTOR MEANS, PRESSURE RESPONSIVE CONTROL MEANS TO VARY THE FLOW OF SAID PUMP TO MAINTAIN A RELATIVELY CONSTANT SYSTEM PRESSURE, UNLOADING MEANS DISPOSED TO SELECTIVELY UNLOAD SAID PRESSURE RESPONSIVE CONTROL MEANS AND BRING SAID PUMP INTO CONDITION OF MINIMUM FLOW AND PRESSURE, MEANS TO ACTUATE SAID UNLOADING MEANS, CONTROL MEANS INTERPOSED BETWEEN AND FUNCTIONALLY INTERCONNECTING SAID MEANS TO ACTUATE SAID UNLOADING MEANS AND SAID MECHANICAL CLUTCH ACTUATING MEANS AND RESPONSIVE TO SELECTIVE POSITIONS OF SAID MECHANICAL CLUTCH ACTUATING MEANS, WHEREBY SELECTIVE POSITIONS OF SAID MECHANICAL CLUTCH ACTUATING MEANS WILL UNLOAD SAID FLUID POWER TRANSMISSION AND CONTROL SYSTEM.