Gantry crane is a type of overhead type crane that develops into crane span structure by setting both landing legs on horizontal cable tray. This type crane runs on ground pathway. It has similar structure to bridge crane in hoisting mechanism, trolley travel mechanism and crane span structure. On account of large span, crane operating mechanism mostly adopts separate driving method to prevent crane from producing deflected operation and increasing resistance, leading to accidents. Gantry cranes application greatly lowers handling labors working strength, perfects workers operation condition and enhances handling operation working capacity and labor productivity. So, it is critical hoisting equipment in enhancing packaging construction quality and benefit.

Gantry crane is mainly applied in transportation and installation in places like open yard, dock, power station, port and railway freight depot. In various industries, we can see its application. For example, it is used in ground combination, manufacturing process coordination, cement frame prefabrication and article swing on electric field equipment. For another, it is applied in railway goods yard for assembling and disassembling train or cars, in ship yard for hoisting ship, in hydropower station dam for lifting gate, in port dock for disassembling container, in factory for craning and transporting cumbersome piece article, in construction installation site for field operation and in lumber storage yard for wood accumulation.

Commonly, gantry crane bridge bilateral landing legs are rigid landing legs. When the span surpasses 30 meters, one side is rigid landing leg and another side becomes flexible landing leg connected to bridge by spherical hinge so that gantry mounting becomes static determinacy system. It is quite the case especially for super large sized gantry crane. In this way, it can avoid subsidiary stress caused by bilateral thrust under the function of external loading. As well, it can compensate crane bridge vertical temperature deformation and gantry crane large windward area. In order to prevent landing leg from sliding or turning over for fierce wind force, it is installed with wind meter and operation structure interlocking crane rail clamp. Out of the aim of expanding operation range, bridge can have no cantilever on both ends, have cantilever on one end or have cantilever on both hands.

As being indicated by gantry crane manufacturer, gantry crane can be divided into following types. Common gantry crane is a mostly widely applied type which can transport various piece article and bulk material. The starting hoisting weight is below 100 tons and span is between 4 to 35 meters. Hydropower station gantry crane is mainly applied for lifting job and starting or stopping gate, also for installation. The starting weight reaches 80 to 500 tons. Its minimum span is between 8 to 16 meters. It has slow hoisting speed. Ship building gantry crane is mainly applied for shipway to assembly ship. The starting lifting weight is commonly at 100 to 1500 tons. And the span can reach 185 meters. Container gantry crane is primarily applied in container dock. The span is determined according to the container bay number needs span. The maximum span is at about 60 meters.