Vehicle speed control

Claim 1

IN COMBINATION WITH A THROTTLE CONTROLLED, ENGINE DRIVEN, VEHICLE TRANSMISSION UNIT HAVING A SOURCE OF RELATIVELY CONSTANT INTENSITY PRESSURE FLUID AND A SOURCE OF VEHICLE SPEED RESPONSIVE PRESSURE FLUID ASSOCIATED THEREWITH, A VEHICLE SPEED SENSING AND SPEED CONTROL DEVICE COMPRISING A FIRST VALVE UNIT CONNECTED TO EACH OF SAID SOURCES OF PRESSURE FLUID AND OPERABLE BY THE PRESSURE VARIATION OF THE VEHICLE SPEED RESPONSIVE PRESSURE FLUID, A SECOND MANUALLY CONTROLLED VALVE UNIT CONNECTED TO SAID SOURCE OF RELATIVELY CONSTANT INTENSITY PRESSURE FLUID, AND A CYLINDER BORE HAVING ONE END CONNECTED TO SAID FIRST VALVE UNIT AND THE OTHER END CONNECTED TO THE SECOND VALVE UNIT BY CONDUIT MEANS ARRANGED TO APPLY SAID RELATIVELY CONSTANT INTENSITY PRESSURE FLUID TO THE OPPOSITE ENDS OF SAID CYLINDER BORE UNDER THE SELECTIVE CONTROL OF SAID FIRST AND SECOND VALVE UNITS, A PISTON MOVABLY MOUNTED IN SAID CYLINDER BORE, AND A PISTON ROD CONNECTED TO SAID PISTON AND TO THE THROTTLE CONTROL FOR SAID VEHICLE ENGINE, SAID PISTON ROD CONNECTION TO SAID PISTON PROVIDING FOR MOVEMENT OF SAID PISTON ROD RELATIVE TO SAID PISTON TOWARDS SAID ONE END OF SAID CYLINDER BORE AND CONJOINTLY THEREWITH TOWARDS SAID OTHER END OF SAID CYLINDER BORE, PRESSURIZATION OF SAID ONE END OF SAID CYLINDER BORE WITH SAID RELATIVELY CONSTANT INTENSITY PRESSURE FLUID APPLYING A FORCE TO SAID PISTON ROD THAT OPPOSES THROTTLE OPENING MOVEMENT OF SAID ENGINE THROTTLE CONTROL AT A PRESELECTED VEHICLE SPEED.