Gantry cranes represent the constructions with the horizontal bridge based on two pillars, moving on land rail tracks. Both bearings have a tight junction with the bridge, while one of the pillars of the bridge can be held by hinges.
Those cranes whose superstructure rests on one side of the support leg and the other one mounted directly on the truck running, are called semi-cranes. Rail tracks in this case are located at different levels, one on land and the other one on a special trestle or columns of the building.
There are two basic schemes used for bridge design – beam and girder. Single-girder bridges with triangular and quadrangular cross section with sled monorail are the most widespread. This construction has proved its cost-efficiency, and the large industry players, like Granada Material Handling, focusing on gantry hoist and overhead crane manufacturing, concentrate plenty of their effort on single-girder bridges.
The span girder and double-girder bridges in their design are usually similar to the beam overhead cranes. Rigid and flexible support of gantry cranes is carried out through individual racks which design depends on the type of support. Flexible support pillar has a single element or a farm, rotate in a direction perpendicular to the bridge. (more…)