crane, truck crane, in particular to a teleskopausleger and a spitzenausleger and method for mounting the spitzenauslegers on teleskopausleger

摘要

A mobile crane comprises a multisection telescopic boom and an optionally usable multisection telescopic lattice type jib (having a base section and axially movable intermediate and fly sections) which when not in use is telescoped and stored on a support in parallel reverse disposition alongside the boom. Each jib section comprises four hollow tubular longitudinal members (each of rectangular cross section) arranged in parallel spaced apart relationship with a plurality of angularly disposed tubular cross braces connected between each pair of members to define a jib section of rectangular cross section. Each longitudinal member is rotated on its axis to present opposite inwardly and outwardly facing flat bearing surfaces and also to present two other opposite flat surfaces to which the ends of the cross braces are welded. Bearing means are provided to facilitate relative sliding motion and to transmit thrust forces between adjacent jib sections. The bearing means comprises inwardly facing slide pads mounted at the lower front ends of the base and intermediate sections and outwardly facing slide pads mounted at the upper and lower rear ends of the intermediate and fly sections; each slide pad being mounted on a support secured within the hollow end of a tubular longitudinal member and engaged with an appropriate bearing surface on an adjacent jib section. To unstore the jib and set it up for use, the foot end of the jib is releasably connected by pivot pin means to the point end of the boom and the boom is partially extended to axially move the jib forward clear of its support. At this stage the unextended jib may be swung 180 DEG about the pivot pin means into axial alignment with the boom and rigidly secured thereto by suitable attachment means. Or, the jib may be partially or fully extended prior to being swung 180 DEG by connecting either the jib intermediate section or the jib fly section, respectively, by releasable rear pin means to the boom base section and by then further extending the boom, either partially or fully, respectively. In all cases, prior to swinging the jib, a guy wire jib mast pivotally attached to the boom point and folded back alongside the boom is swung into upright position. The jib is designed so that it can be rigidly connected at an angle to the boom axis and so that the jib fly section can be rigidly connected at an angle to the jib axis.