Abstract: An extensible stabilizing tower similar to those positioned about hydraulic cylinders having multiple extensible stages is modified to effectively connect cylinders vertically in series. An upper stage of the stabilizing tower supports an upper cylinder or parallel cylinders, and base parallel cylinders connected to the base of the stabilizing tower are operative to lift the upper stage supporting the upper cylinder. A load connected to the header of the upper cylinder is lifted a distance equal to the sum of the extension of the base cylinders and the subsequent extension of the upper cylinder.

Abstract: A large gantry for straddling and handling a heavy load comprises a pair of vertical support assemblies which support a horizontal load-bearing gantry beam. Each support assembly comprises three vertically disposed independently extendable/retractable hydraulic rams. A tiltable self-leveling sole plate is located between the upper ends of the three rams in each support assembly and the underside of an end of the gantry beam. A control system which includes selectively operable panel-mounted joy-stick actuated control switches and control valves effects operation of the rams in unison to raise and lower the gantry beam and also effects independent individual operation of any ram to level the beam if necessary. The arrangement increases the stability, the load-handling capacity and the operational safety of the gantry.