A bridge type crane arranged on two supporting legs to form a portal frame. This kind of crane runs on the ground track, which is mainly used for carrying and installing in the open storage yard, dock, power station, port and railway freight station. Gantry crane lifting mechanism, trolley running mechanism and bridge structure, and bridge crane is basically the same. Due to the large span, most of the crane operating mechanism adopts the separate driving mode to prevent the crane from running askew and increasing the resistance, or even accidents. Gantry crane crane trolley running on the bridge, some crane trolley is an jib crane. The supporting legs on both sides of the bridge are generally rigid; When the span is more than 30 meters, one side is usually a rigid supporting leg, while the other side is a flexible supporting leg connected with the bridge through the ball hinge, making the portal frame a statically determinate system, which can avoid additional stress caused by lateral thrust under external load, and can also compensate for the longitudinal temperature deformation of the bridge. The gantry crane has a large wind area. In order to prevent it from sliding or toppling under the action of strong wind, it is equipped with a wind meter and a crane rail clamp which is interlocked with the operating mechanism. The bridge may be cantilevered at either end; It may also be cantilevered at one end or at both ends to extend the operating range. The semi-gantry crane bridge has supporting legs at one end and no supporting legs at the other end. There are four types of gantry cranes.
(1) general gantry crane: this crane (see color map) is the most widely used, can carry a variety of articles and scattered materials, lifting weight of 100 tons or less, span of 4 ~ 35 meters. The working level of ordinary gantry crane with grab bucket is higher.
Longmen crane of hydropower station: it is mainly used for lifting and opening and closing gate, and can also be installed. It has a lifting weight of 80 ~ 500 tons and a small span of 8 ~ 16 meters. The lifting speed is low, 1 ~ 5 m/min. Although this crane is not often lifted, but once the use of work is very heavy, so appropriate to raise the level of work.
(3) shipbuilding gantry crane: used for building the hull of the slipway, there are always two lifting carts: one has two main hooks, in the bridge flange of the track; The other, with a main hook and a secondary hook, runs on a track under the bridge flange to flip and lift large hull sections. Lifting weight is generally 100 ~ 1500 tons; The span is 185 meters; The lifting speed is 2 ~ 15 m/min, and the fretting speed is 0.1 ~ 0.5 m/min.
Gantry container crane: for container terminal. The quaywall container carrier bridge will be transferred from the ship to the yard or the rear by the trailer, which will be piled up by the container gantry crane or directly loaded onto the truck, thus speeding up the turnover of the container carrier bridge or other cranes. Can pile up 3 ~ 4 layers high, wide 6 rows of containers yard, generally used in the form of tires, but also useful rail. Compared with the container gantry crane, its span and the height on both sides of the gantry are larger. In order to meet the transportation needs of the port wharf, this kind of crane works at a higher level. Lifting speed is 8 ~ 10 m/min; The span is determined by the number of container rows that need to be crossed, the maximum is about 60 meters. The corresponding starting weights for 20ft, 30ft and 40ft containers are about 20t, 25t and 30t respectively.
Introduction to gantry crane