Abstract: A mobile lifting apparatus having an extendable boom assembly supported by a plurality of hydraulic cylinders extending upwardly from a wheeled chassis, and further having a fork attachment coupled to the extendable boom assembly. The fork attachment is configured to engage palletized loads and permits such loads to be raised and transported upon extension of the hydraulic cylinders. The fork attachment includes a buttress assembly that remains relatively stationary as the boom assembly is horizontally extended and retracted. The fork assembly further includes a pair of forks that are pivotal relative to the buttress assembly around a generally horizontal axis. The forks are coupled to the horizontally extendable portion of the boom assembly so that extension and retraction of the boom pivots the forks to change the angular orientation of the forks relative to horizontal. Such angular movement of the forks facilitates engagement and disengagement of the forks with the palletized load.

Abstract: A mobile lifting apparatus has a chassis with front driving wheels and steerable rear wheels. A vertical mast comprised of a pair of extendible hydraulic cylinders is spacedly mounted on the front of the chassis. One or more jam stay cylinders are mounted on the chassis rearwardly of the vertical mast. A pair of extendable booms are mounted on the vertical mast and jam stay cylinders. The load may be attached to the end of the booms. A hydraulic or other power supply extends and retracts the boom and drives the driving wheels. A counterweight is mounted on the rear of the chassis and the chassis may be extended to increase the capacity and stability of the lifting apparatus.

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.