| 摘要 |
A HYDRAULIC CIRCUIT SYSTEM FOR A JACK COMPRISES AN INLET CIRCUIT, A RETURN CIRCUIT AND AN OVERLOAD PROTECTION CIRCUIT WITH A PISTON-CYLINDER ASSEMBLY (4, 10), A SEQUENCE VALVE (B), A SAFETY VALVE (D) AND A RELIEF VALVE (C), THE INLET CIRCUIT EXTENDING FROM AN OUTER RESERVOIR (2) VIA A CHECK VALVE (A1) TO AN OIL CHAMBER (3) OF A MANUAL PUMP (20), THE OIL CHAMBER (3) BEING CONNECTED TO AN INNER OIL CHAMBER (41) FORMED IN THE PISTON ROD (4) VIA ANOTHER CHECK VALVE (A2) TO FORM A CLOSED CIRCUIT. THE OIL CHAMBER (3) OF THE PUMP (20) IS CONNECTED TO AN INNER RESERVOIR (1) IN THE HYDRAULIC CYLINDER (10) VIA A SEQUENCE VALVE (B), AND THE INNER RESERVOIR (1) IS CONNECTED TO THE OUTER RESERVOIR (2) VIA A CHECK VALVE (A3). WHEN THE MAXIMUM EFFECT CAPACITY OF THE OIL CHAMBER (3) OF THE PUMP (20) A GREATER THAN OR EQUAL TO THAT OF THE INNER OIL CHAMBER (41) OF THE PISTON ROD (4), A SINGLE TOUCH OF THE PUMP (20) CAN RAISE THE HYDRAULIC JACK TO A REQUIRED LOADING POSITION UNDER NO LOAD OR LIGHT LOAD CONDITIONS.(FIG. 1) |
