Hydraulic starting system and valves therefor

Claim 1

A HYDRAULIC STARTING AND PUMPING SYSTEM COMPRISING (A) AN OVERCENTER MOTOR-PUMP UNIT HAVING HIGH AND LOW PRESSURE PORTS AND A DISPLACEMENT CONTROL ELEMENT WHICH IS MOVABLE BETWEEN POSITIONS AT OPPOSITE SIDES OF A ZERO DISPLACEMENT POSITION TO REVERSE THE DIRECTION OF FLOW THROUGH THE UNIT; (B) AN ACCUMULATOR FOR SUPPLYING MOTIVE FLUID TO THE MOTOR-PUMP UNIT TO DRIVE SAME AS A MOTOR; (C) FIRST CONDUIT MEANS CONNECTING THE ACCUMULATOR WITH THE HIGH PRESSURE PORT AND CONTROLLED BY A START VALVE; (D) A FLUID RESERVOIR; (E) PRESSURE ACTUATED MEANS FOR POSITIONING THE DISPLACEMENT CONTROL ELEMENT AND INCLUDING A FLUID PRESSURE MOTOR, A VALVE HAVING SUPPLY AND EXHAUST POSITIONS IN WHICH, RESPECTIVELY, IT CONNECTS THE MOTOR WITH THE HIGH PRESSURE PORT AND THE RESERVOIR, AND AN ACTUATING MOTOR FOR HOLDING THE VALVE IN ONE OF ITS POSITIONS DURING THE STARTING CYCLE; (F) SECOND CONDUIT MEANS CONNECTING THE ACTUATING MOTOR WITH THE FIRST CONDUIT MEANS; (G) MEANS FOR PERMITTING FLOW FROM THE ACCUMULATOR TO THE SECOND CONDUIT MEANS ONLY WHEN THE START VALVE IS OPEN; (H) MEANS FOR PREVENTING FLOW FROM THE MOTOR-PUMP UNIT TO THE SECOND CONDUIT MEANS; (I) A CHECK VALVE IN THE SECOND CONDUIT MEANS ORIENTED TO PREVENT FLOW FROM THE ACTUATING MOTOR; (J) THIRD CONDUIT MEANS CONNECTING THE ACTUATING MOTOR WITH THE RESERVOIR; (K) A VENT VALVE CONTROLLING THE THIRD CONDUIT MEANS; AND (L) ACTUATING MEANS WHICH CLOSES AND OPENS THE VENT VALVE AS IT OPENS AND CLOSES, RESPECTIVELY, THE START VALVE.