Constant-speed reciprocable hydropneumatic motor

Claim 1

A UNDIRECTIONALLY CONSTANT-SPEED RECIPROCABLE HYDROPNEUMATIC MOTOR COMPRISING A CYLINDER HAVING A CYLINDER BORE THEREIN AND HAVING A CLOSED END AND AN OPEN END, A RESTRAINED PISTON RECIPROCABLY MOUNTED IN SAID CYLINDER BORE, SAID RESTRAINED PISTON HAVING A PISTON HEAD DEFINING WITH SAID CYLINDER BORE AND CLOSED END AN INNER CHAMBER ADAPTED TO CONTAIN HYDRAULIC FLUID, SAID RESTRAINED PISTON HAVING A HOLLOW RESTRAINING PISTON ROD EXTENDING FROM SAID PISTON HEAD OUTWARDLY THROUGH THE OPEN END OF SAID CYLINDER AND HAVING A CLOSED OUTER END, SAID PISTON ROD HAVING A LONGITUDINAL BORE THEREIN, A FREE PISTON FLOATINGLY MOUNTED IN SAID RESTRAINED PISTON ROD BORE AND DEFINING WITH SAID PISTON HEAD A MIDDLE CHAMBER ADAPTED TO CONTAIN HYDRAULIC FLUID AND DEFINING WITH SAID CLOSED PISTON ROD END AN OUTER CHAMBER ADAPTED TO CONTAIN A COMPRESSED PNEUMATIC FLUID, AND YIELDING-URGED VALVE MEANS IN SAID PISTON HEAD HAVING A VALVE PASSAGEWAY OF VARIABLE CROSS-SECTIONAL AREA INTERCONNECTING SAID INNER AND MIDDLE CHAMBERS, SAID VALVE MEANS BEING RESPONSIVE TO THE FLOW OF HYDRAULIC FLUID IN ONE DIRECTION BETWEEN SAID MIDDLE CHAMBER AND SAID INNER CHAMBER RESULTING FROM RELATIVE MOTION BETWEEN SAID CYLINDER AND SAID RESTRAINED PISTON IN ONE DIRECTION FOR VARYING THE EFFECTIVE CROSS-SECTIONAL AREA OF SAID VALVE PASSAGEWAY TO MAINTAIN A SUBSTANTIALLY CONSTANT RATE OF FLOW OF HYDRAULIC FLUID THROUGH SAID PASSAGEWAY IN SAID ONE DIRECTION OF HYDRAULIC FLUID FLOW, SAID VALVE MEANS INCLUDING A MOVABLE VALVE MEMBER AND RESILIENT MEANS URGING SAID VALVE MEMBER IN A PASSAGEWAY-OPENING DIRECTION, SAID VALVE MEMBER HAVING AN ORIFICE THEREIN RESPONSIVE TO FLOW OF HYDRAULIC FLUID THERETHROUGH TO CREATE A DIFFERENTIAL PRESSURE ON OPPOSITE SIDES THEREOF TO MOVE SAID VALVE MEMBER IN THE DIRECTION OF SAID FLOW IN A PASSAGEWAY-CLOSING DIRECTION WHICH IN COOPERATION WITH THE OPPOSING URGE OF SAID RESILIENT MEANS UPON SAID VALVE MEMBER VARIES THE CROSS-SECTIONAL AREA OF SAID VALVE PASSAGEWAY TO MAINTAIN A CONSTANT RATE OF HYDRAULIC FLUID FLOW IN ONE DIRECTION THERETHROUGH AND CONSEQUENTLY TO IMPART A CONSTANT SPEED OF RECIPROCATION OF SAID MOTOR IN ONE DIRECTION IRRESPECTIVE OF THE VARIATION OF HYDRAULIC PRESSURE WITHIN SAID MOTOR.