Introduction: for the ship to assemble the hull, standing with two lifting trolley: one has two main hook, on the track in the trajectory of the bridge; the other has a main hook and a hook, Run on the track in order to flip and hoist large hull segments. Lifting capacity is generally 100 to 1500 tons; span of 185 meters; lifting speed of 2 to 15 m / min, there are 0.1 to 0.5 m / min fretting speed.
Gantry crane hoisting mechanism, car running mechanism and bridge structure, and bridge crane is basically the same. As the span is large, the crane operating mechanism are mostly driven separately to prevent the crane from generating skew operation and increase resistance, and even accidents. Gantry crane crane is running on the bridge, and some crane is a boom crane. The legs on both sides of the bridge are generally rigid legs; span of more than 30 meters, often one side of the rigid legs, and the other side through the ball hinge and bridge connecting the flexible legs, so that the gantry into a static system , So as to avoid the external load due to lateral thrust caused by additional stress, but also to compensate for the longitudinal deformation of the bridge gantry crane wind area, in order to prevent the use of strong winds under the taxi or tipping, equipped with wind measuring instrument and A crane gripper for interlocking with an operating mechanism. The bridge can be either cantilevered at both ends; it can also be cantilevered at one end or both ends to expand the operating range. The semi-gantry crane has one end with a leg and the other end without a leg, running directly on a high platform.