Hydraulic boom for gantry and the like

摘要

A hydraulic boom gantry and a method of lifting a load associated therewith. The gantry includes telescoping sections with a hydraulic cylinder mounted therein. A swiveling plate structure allows minor deviation between sets of telescoping sections. A collar structure and a pinning structure lock the telescoping sections together. A cam mechanism prevents accidental section retraction and a powered rigging device traverses a beam connecting the telescoping sections.