| 摘要 |
A triangulated gantry includes a front ground-supported boom positioned laterally between and longitudinally remote from left and right rear ground-supported booms of the machine. The booms are functionally interconnected by a system of horizontal beams that may form an at least generally triangular shape when viewed in top plan. The resultant gantry is extremely stable and extremely maneuverable when compared to traditional four boom gantries. Maneuverability may be enhanced further by configuring each of the bases of the booms so as to be steerable through an angle of at least 360° with respect to the remainder of the boom. One or more of the horizontal beams may be extendible and retractable to increase and reduce the size of the footprint of the machine, permitting the machine to maneuver towards a load through tight spaces and to subsequently expand to straddle the load.
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