Crane self-assembly system

Abstract

A method of assembling a heavy duty mobile crane having a load handling boom that has a boom base section and other component parts. The method includes positioning the component parts adjacent said crane, such as on a truck, raising the parts from the truck bed in sequence with a self-contained lifter associated with said base section, lowering and placing each part in a position adjacent ground level for connection to said crane, and then connecting the parts to the crane so as to provide a complete working crane. The method applies particularly to assembling the boom sections and connecting them to the crane. Extension sections of the boom are handled by placing them at ground level and preassembling the sections to form an upper boom, and then connecting the upper boom to the base section. The method steps are reversed to disassemble the crane. The method also includes transporting the crane to a work site with the boom base section connected to the mobile crane. The apparatus to carry out the method includes a lifter, preferably a pair of hydraulic cylinders, mounted in the base section of the boom. A line, such as a wire rope, is attached to each cylinder and extends over a sheave adjacent the distal end of the base section. A sling may be attached to the hook on the end of the lines for handling the component parts of the crane. For certain parts, such as counterweights, a hook or other connector is attached directly to the part. The lines are snugged when not in use with the hook/connector coupled to an eye on the underside of the boom base section.