Classification of gantry cranes

Gantry cranes can be classified according to gantry structure, main beam structure and use form. 1. According to the portal structure, it can be divided into portal crane and cantilever portal crane. Gantry crane 1. Full gantry crane: the main girder is not cantilevered, and the trolley is carried out in the main span. 2. Semi-portal crane: The height difference of legs can be determined according to the requirements of site civil engineering. Cantilever gantry crane 1. Double cantilever gantry crane: the most common structural form, with reasonable structural stress and effective use of site area. 2. Single cantilever gantry crane: due to the limitation of the site, this structure is often chosen. Second, according to the main girder form 1. The single-beam gantry crane has the advantages of simple structure, convenient manufacture and installation, and light weight. The main beams are mostly derailed box frame structures. Compared with the double-beam gantry crane, the overall stiffness is weak. Therefore, this form can be adopted when the lifting weight Q is ≤ 50t and the span S is ≤ 35m. There are two kinds of portal legs of single-beam gantry crane: L-shaped and C-shaped. L-shape is easy to manufacture and install, with good stress conditions and light weight, but the space for lifting goods through legs is relatively small. The C-shaped leg is made into an inclined or curved shape, in order to have more lateral space for goods to pass through the leg smoothly. 2. Double-beam double-beam gantry crane has strong bearing capacity, long span, good overall stability and many varieties, but its own mass is larger and its cost is higher than that of single-beam gantry crane with the same lifting capacity. According to the difference of main girder structure, it can be divided into box girder and truss. Generally, box structure is adopted. Three, according to the main girder structure 1. Truss beam is welded by angle steel or I-beam, which has low cost, light weight and good wind resistance. However, due to many welding points and the defects of the truss itself, the truss beam also has some shortcomings, such as large deflection, small stiffness, relatively low reliability and frequent detection of welding points. Suitable for places with low safety requirements and small lifting weight. 2. The box girder is welded by steel plates, which has the characteristics of high safety and high rigidity. Generally used for large tonnage and super-large tonnage gantry cranes. As shown in the picture on the right, MGhz 1200, lifting capacity 1200 tons, is the largest portal crane in China, and the main girder adopts box beam structure. Box girder also has the disadvantages of high cost, heavy weight and poor wind resistance. 3. Honeycomb beams are generally called "isosceles triangular honeycomb beams". The end face of the main girder is triangular, with honeycomb holes on the inclined abdomen on both sides and chords on the upper and lower sides. Honeycomb beam absorbs the characteristics of truss beam and box beam, and has greater stiffness, smaller deflection and higher reliability than truss beam. However, due to the use of steel plate welding, the weight and cost are slightly higher than those of truss beams. Suitable for sites or beam yards with frequent use or large lifting capacity. Because this type of beam is a patented product, there are few manufacturers. Fourth, according to the use form 1. Common Gantry Crane Track Gantry Crane This kind of cranes mostly adopt box-type and truss-type structures, which are the most widely used. It can carry all kinds of finished goods and bulk materials, with a lifting weight below100t and a span of 4-39m. The working level of ordinary gantry crane with grab bucket is higher. Ordinary gantry cranes mainly refer to hook, grab, electromagnetic and hoist gantry cranes, as well as semi-gantry cranes. 2. The gantry crane of hydropower station is mainly used for hoisting and opening and closing the gate, and can also be installed. The lifting capacity is 80 ~ 500 tons, and the small span is 8 ~16m; The lifting speed is low, which is 1 ~ 5m/min. Although this kind of crane is not often hoisted, once it is used, the work is very heavy and it needs to be improved appropriately. 3. Shipbuilding gantry crane is used to assemble the hull on the berth, and there are always two lifting trolleys: one with two main hooks runs on the track on the upper flange of the bridge; The other one has a main hook and an auxiliary hook, which runs on the track of the flange under the bridge to overturn and hoist large hull sections. The lifting weight is generally 100 ~ 1500 tons; Span185m; The lifting speed is 2 ~ 15m/min, and there is also a fretting speed of 0. 1 ~ 0.5m/min. 4. Container gantry crane is used in container terminal. The trailer will transport the container rail gantry crane unloaded from the container crane on the shore to the yard or the rear, and then it will be piled up by the container gantry crane or directly loaded and transported away, which can speed up the turnover of the container crane or other cranes. Generally, the yard where 3 ~ 4-storey and 6-row wide containers can be stacked is of tire type or track type. Compared with the container straddle carrier, the container gantry crane has a larger span and a higher height on both sides of the gantry. In order to meet the transportation needs of ports and docks, the working level of this crane is relatively high. The lifting speed is 8 ~10m/min; The span is determined according to the number of container rows to be crossed. The maximum span is about 60 meters, corresponding to the lifting weights of 20-foot, 30-foot and 40-foot containers of about 20 tons, 25 tons and 30 tons respectively.