Jack

Claim 1

IN A JACK, CYLINDER MEANS, AN EXTENDABLE RAM MEANS HAVING A PISTON ASSEMBLY RECIPROCABLY MOUNTED IN SAID CYLINDER MEANS, A FLUID RESERVOIR, OPERATING PASSAGE MEANS CONNECTING SAID FLUID RESERVOIR TO SAID CYLINDER MEANS, VALVE MEANS CONTROLLING FLOW OF FLUID BETWEEN SAID CYLINDER MEANS AND SAID FLUID RESERVOIR, PUMP MEANS TO PUMP FLUID FROM SAID RESERVOIR INTO SAID CYLINDER MEANS TO EXTEND SAID RAM MEANS, BYPASS PASSAGE MEANS CONNECTING SAID CYLINDER MEANS TO SAID FLUID RESERVOIR TO PROVIDE A BYPASS FOR RETURNING FLUID FROM SAID CYLINDER MEANS TO SAID FLUID RESERVOIR, VALVE MEANS MOUNTED ON AND MOVABLE WITH SAID RAM MEANS FOR CONTROLLING SAID BYPASS PASSAGE MEANS, SAID VALVE MEANS COMPRISING A SLEEVE MEMBER MOVABLY MOUNTED ON SAID RAM MEANS FOR MOVEMENT BETWEEN SPACED POSITIONS AND BEING SPACED FROM SAID PISTON ASSEMBLY, A VALVE MOVABLE TO AN OPEN BYPASS POSITION DURING MOVEMENT OF SAID SLEEVE MEMBER TO ONE SPACED POSITION AND MOVABLE TO A CLOSED BYPASS POSITION DURING MOVEMENT OF SAID SLEEVE MEMBER TO THE OTHER SPACED POSITION, MEANS TO NORMALLY BIAS SAID SLEEVE MEMBER TO SAID OTHER SPACED POSITION, AND MEANS LOCATED IN ENGAGING ALIGNMENT WITH SAID SLEEVE MEMBER IN A PREDETERMINED EXTENDED POSITION OF SAID RAM MEANS AND ADAPTED TO ENGAGE AND DISPLACE SAID SLEEVE MEMBER TOWARD SAID ONE POSITION TO BYPASS FLUID THEREAFTER TENDING TO FURTHER EXTEND SAID RAM MEANS.