Speed and directional control valve for double acting lift cylinder

Claim 1

A CONTROL VALVE FOR A REVERSIBLE FLUID MOTOR, CHARACTERIZED BY: (A) A BODY MEMBER HAVING (1) AN INLET TO RECEIVE PRESSURE FLUID FROM A PUMP, (2) FIRST AND SECOND SERVICE PASSAGES WHICH ARE ADAPTED TO BE CONNECTED WITH THE OPPOSITE SIDES OF A FLUID MOTOR, (3) AND AN OUTLET COMMON TO SAID SERVICE PASSAGES AND THROUGH WHICH FLUID CAN BE RETURNED TO A RESERVOIR; (B) A VALVE MEMBER IN THE BODY MEMBER, MOVABLE FROM A NEUTRAL POSITION TO AT LEAST THREE WORKING POSITIONS; (C) COOPERATING MEANS IN THE BODY MEMBER AND ON THE VALVE MEMBER EFFECTIVE IN A FIRST WORKING POSITION OF THE VALVE MEMBER TO DIRECT FLUID FROM THE INLET TO THE FIRST SERVICE PASSAGE AND TO DIRECT EXHAUST FLUID RETURNING TO THE SECOND SERVICE PASSAGE TO SAID OUTLET, SAID MEANS INCLUDING FLOW CONTROLLING MEANS IN ONE OF SAID MEMBERS, WHICH IS EFFECTIVE IN SAID FIRST WORKING POSITION OF THE VALVE MEMBER TO RESTRICT FLOW OF EXHAUST FLUID TO THE OUTLET, WHEREBY A MOTOR THEN CONNECTED WITH THE SERVICE PASSAGES WILL BE CAUSED TO OPERATE IN ONE DIRECTION AT A SUBSTANTIALLY SLOW RATE, SAID FLOW CONTROLLING MEANS BEING RENDERED INEFFECTIVE IN CONSEQUENCE OF MOVEMENT OF THE VALVE MEMBER TO ALL OTHER POSITIONS THEREOF INCLUDING ITS NEUTRAL POSITION; (D) COOPERATING MEANS IN THE BODY MEMBER AND ON THE VALVE MEMBER EFFECTIVE IN A SECOND WORKING POSITION OF THE VALVE MEMBER TO DIRECT FLUID FROM THE INLET TO THE SECOND SERVICE PASSAGE AND TO DIRECT EXHAUST FLUID RETURNING TO THE FIRST SERVICE PASSAGE TO SAID OUTLET, ALL IN BYPASS RELATION TO SAID FLOW CONTROLLING MEANS, SO AS TO CAUSE OPERATION OF THE MOTOR IN THE OPPOSITE DIRECTION AT ONE SPEED, AND EFFECTIVE IN A THIRD WORKING POSITION OF THE VALVE MEMBER TO DIRECT SAID EXHAUST FLOW FROM THE FIRST SERVICE PASSAGE TO THE SECOND SERVICE PASSAGE WHILE MAINTAINING FLOW OF FLUID FROM THE INLET TO THE SECOND SERVICE PASSAGE, ALL IN BYPASS RELATION TO SAID FLOW CONTROLLING MEANS, SO AS TO CAUSE OPERATION OF THE MOTOR IN SAID OPPOSITE DIRECTION AT A HIGHER SPEED; (E) AND COOPERATING MEANS IN THE BODY MEMBER AND ON THE VALVE MEMBER EFFECTIVE IN THE NEUTRAL POSITION OF THE VALVE MEMBER TO CLOSE OFF THE SERVICE PASSAGES FROM THE INLET AND TO BLOCK COMMUNICATION BETWEEN THE INLET AND SAID FLOW CONTROLLING MEANS.