Hydraulic pump

Claim 1

A VARIABLE DISPLACEMENT PUMP DEVICE FOR USE IN VARIOUSLY CONTROLLING A HYDRAULIC CYLINDER AND PISTON ACTUATOR UNITS CONNECTED WITH A CONVENTIONAL OUTBOARD MOTOR FOR TILTING THE SAME RELATIVE TO ITS MOUNTING ABOUT A HORIZONTAL TRANSVERSE AXIS, SAID DEVICE COMPRISING: A HOUSING STRUCTURE HAVING A RESERVOIR CHAMBER THEREIN ADAPTED TO CONTAIN A PREDETERMINED AMOUNT OF HYDRAULIC FLUID, A FIRST RECESS IN SAID HOUSING DEFINING A LOW PRESSURE LARGE VOLUME DISPLACEMENT CHAMBER, A SECOND RECESS IN SAID HOUSING OF SUBSTANTIALLY SMALLER VOLUMETRIC SPACE THAN SAID FIRST RECESS AND DEFINING A HIGH-PRESSURE, LOW-VOLUME DISPLACEMENT CHAMBER, A PAIR OF MANUALLY OPERABLE ELONGATE DISPLACEMENT PISTONS EACH BEING RECIPROCABLE WITHIN ONE OF SAID DISPLACEMENT CHAMBERS, SAID DISPLACEMENT PISTON WITHIN SAID LOW-PRESSURE, HIGH-VOLUME CHAMBER BEING SUBSTANTIALLY LARGER THAN THE PISTON WITHIN THE HIGH-PRESSURE, LOW-VOLUME CHAMBER, EACH OF SAID PISTONS HAVING ONE END THEREOF PROJECTING EXTERIORLY OF THE HOUSING STRUCTURE, A PAIR OF ACTUATING MEMBERS EACH BEING SECURED TO ONE OF SAID EXTERIORLY PROJECTING ENDS OF THE PISTONS, EACH PISTON BEING SUBSTANTIALLY SMALLER IN CROSS-SECTIONAL SIZE THAN THE ASSOCIATED DISPLACEMENT CHAMBER, A PAIR OF PASSAGES IN SAID HOUSING, EACH INTERCONNECTING SAID RESERVOIR CHAMBER AND ONE OF SAID DISPLACEMENT CHAMBERS, A PAIR OF SUBSTANTIALLY IDENTICAL PRESSURE RESPONSIVE VALVE MEMBERS EACH NORMALLY CLOSING ONE OF SAID PASSAGES, AND OPENING ITS ASSOCIATED PASSAGE IN RESPONSE TO A REDUCTION OF FLUID PRESSURE IN THE ASSOCIATED DISPLACEMENT CHAMBER, A DISCHARGE PORT IN SAID HOUSING CONNECTIBLE IN COMMUNICATING RELATION WITH CYLINDER AND PISTON ACTUATOR UNITS WHICH ARE CONNECTED TO THE OUTBOARD MOTOR FOR ADJUSTABLY TILTING THE SAME ABOUT A TRANSVERSE HORIZONTAL AXIS, A TRANSFER PASSAGE IN SAID HOUSING INTERCONNECTED IN COMMUNICATING RELATION WITH SAID DISPLACEMENT CHAMBERS AND BEING INTERCONNECTED IN COMMUNICATING RELATION WITH SAID DISCHARGE PORT, WHEREBY FLUID INTRODUCED INTO A SELECTED DISPLACEMENT CHAMBER DURING THE RETRACTION STROKE OF THE ASSOCIATED PISTON WILL BE DIRECTED THROUGH THE DISCHARGE PORT DURING THE RETURN STROKE OF SAID LAST MENTIONED PISTON, A PAIR OF SIMILAR EXPANSION CHAMBERS EACH BEING INTERPOSED BETWEEN AND INTERCONNECTED TO ONE OF SAID DISPLACEMENT CHAMBERS AND SAID TRANSFER PASSAGE, A RETURN PASSAGE IN SAID HOUSING INTERCONNECTING SAID TRANSFER PASSAGE IN COMMUNICATING RELATION WITH SAID RESERVOIR CHAMBER, AND AN ADJUSTABLE VALVE INTERPOSED IN FLOW CONTROLLING RELATION BETWEEN SAID TRANSFER AND RETURN PASSAGES FOR SELECTIVELY CLOSING AND OPENING SAID RETURN PASSAGE WITH RESPECT TO SAID TRANSFER PASSAGE.