Hydraulic device

Claim 1

A HYDRUALIC SYSTEM FOR ACCELERATING AN ENGINE COMPRISING (A) A HYDRAULIC MOTOR CONNECTED WITH THE ENGINE FOR DRIVING SAME AND HAVING INLET AND DISCHARGE PORTS; (B) AN AUXILIARY ENGINE; (C) A HYDRAULIC MOTOR-PUMP UNIT OF THE OVERCENTER TYPE CONNECTED WITH THE AUXILIARY ENGINE AND HAVING HIGH AND LOW PRESSURE PORTS AND A DISPLACEMENT CONTROL ELEMENT SHIFTABLE BETWEEN FIRST SECOND MAXIMUM DISPLACEMENT POSITIONS ON OPPOSITE SIDES OF A NEUTRAL ZERO DISPLACEMENT POSITION; (D) AN ACCUMULATOR; (E) A FIRST CONDUIT CONNECTING THE ACCUMULATOR WITH THE HIGH PRESSURE PORT OF THE MOTOR-PUMP UNIT; (F) MEANS BIASING THE DISPLACEMENT CONTROL WITH THE TOWARD THE FIRST MAXIMUM DISPLACEMENT POSITION; (G) A FLUID PRESSURE CONTROL MOTOR CONNECTED WITH THE DISPLACEMENT CONTROL ELEMENT FOR MOVING IT TOWARD THE SECOND MAXIMUM DISPLACEMENT POSITION; (H) A SECOND CONDUIT CONNECTING THE HIGH PRESSURE PORT OF THE MOTOR-PUMP UNIT WITH THE INLET PORT OF THE HYDRAULIC MOTOR; (I) FIRST AND SECOND STARTER VALVES CONTROLLING FLOW THROUGH THE FIRST AND SECOND CONDUITS, RESPECTIVELY, EACH VALVE BEING SHIFTABLE BETWEEN OPEN AND CLOSED POSITIONS; (J) A CONTROL VALVE HAVING AN INLET PASSAGE CONNECTED WITH THE HIGH PRESSURE PORT OF THE MOTOR-PUMP UNIT, AN OUTLET PASSAGE CONNECTED WITH THE CONTROL MOTOR, AND AN EXHAUST PASSAGE AND INCLUDING A MOVABLE VALVE MEMBER SHIFTABLE BETWEEN FIRST AND SECOND POSITIONS IN WHICH, RESPECTIVELY, THE OUTLET PASSAGE IS CONNECTED WITH THE EXHAUST PASSAGE AND THE INLET PASSAGE AND HAVING AN INTERMEDIATE LAP POSITION IN WHICH THE OUTLET PASSAGE IS ISOLATED FROM BOTH THE EXHAUST PASSAGE AND THE INLET PASSAGE; (K) A SPRING BIASING THE VALVE MEMBER TOWARD THE FIRST POSITION; (L) A MOVABLE SPRING SEAT FOR THE SPRING SHIFTABLE BETWEEN LOW SPRING LOAD AND HIGH SPRING LOAD POSITIONS; (M) MEANS RESPONSIVE TO THE PRESSURE IN THE INLET PASSAGE FOR URGING THE VALVE MEMBER TOWARD THE SECOND POSITION; (N) A FIRST ACTUATING MOTOR ACTING IN OPPOSITION TO THE SPRING; (O) A SECOND ACTUATING MOTOR CONNECTED WITH THE MOVABLE SPRING SEAT AND ARRANGED TO MOVE THE SEAT TOWARD THE HIGH SPRING LOAD POSITION; (P) RESERVOIR MEANS CONNECTED WITH THE LOW PRESSURE PORT OF THE MOTOR-PUMP UNIT, THE DISCHARGE PORT OF THE HYDRAULIC MOTOR, AND THE EXHAUST PASSAGE OF THE CONTROL VALVE; (Q) MEANS FOR SELECTIVELY ENERGIZING AND DE-ENERGIZING THE FIRST ACTUATING MOTOR; AND (R) MEANS FOR SELECTIVELY ENERGIZING AND DE-ENERGIZING THE SECOND ACTUATING MOTOR.