Lifting device

Claim 1

A LIFTING DEVICE INCLUDING FIRST AND SECOND CYLINDRICAL MEMBERS, SAID MEMBERS BEING POSITIONED IN TELESCOPIC RELATION, SAID FIRST CYLINDRICAL MEMBER INCLUDING A TOP CLOSURE WALL AND THEREBY FORMING A CLOSED CHAMBER WHICH IS OPEN AT THE BOTTOM, SEAL MEANS CARRIED BY ONE OF SAID MEMBERS AND COOPERATING WITH THE OTHER OF SAID MEMBERS TO PREVENT LEAKAGE THEREBETWEEN, SAID SECOND CYLINDRICAL MEMBER INCLUDING A LOWER PORTION ENGAGING A SUPPORTING SURFACE, SAID SECOND MEMBER BEING ALSO OPEN TO SAID SUPPORTING SURFACE, PRESSURE MEANS BETWEEN SAID MEMBERS FOR URGING SAID MEMBERS APART, MEANS FOR CONDUCTING SAID PRESSURE MEANS INTO SAID CHAMBER, VALVE MEANS INCLUDED IN SAID CONDUCTING MEANS AND HAVING AN OPENING, MEANS OPERATIVELY CONNECTED TO SAID VALVE MEANS AND RESPONSIVE TO THE RELATIVE POSITION OF SAID MEMBERS FOR VARYING SAID OPENING AND REGULATING THE VERTICAL POSITION OF SAID FIRST MEMBER, A PARTITION EXTENDING TRANSVERSELY OF SAID CYLINDRICAL MEMBER AND DIVIDING SAID CHAMBER INTO UPPER AND LOWER SPACES, SAID PARTITION CARRYING SAID SEAL MEANS, SAID VALVE OPENING COMMUNICATING WITH SAID UPPER SPACE, AND METERING PASSAGE MEANS IN SAID PARTITION CONNECTING SAID SPACES FOR METERING THE FLOW FROM SAID UPPER SPACE TO SAID LOWER SPACE.