1. The main beam in the form of single-master single girder gantry crane girder structure is simple, easy to manufacture and installation, low quality of their main beam mostly Partial rail box-shaped frame structure. Compared with double girder gantry crane, the overall stiffness weaker. Therefore, when the starting weight Q≤50t, when the span S≤35m, can this form. Single girder gantry crane doors leg has L and C forms. L type of manufacture and installation convenience, the force was better, the smaller their own quality, but, lifting goods through space at the relatively small number of legs. C-type legs made of sloped or curved shape, aimed at a greater horizontal space, so that goods pass foot. 2. The double main beam double girder gantry crane carrying capacity, span, the overall stability, variety, but the quality of their starting weight compared with the same single-girder gantry crane to be bigger, the cost is higher. Depending on the main beam structure, it can be divided into box beams and trusses in two forms. More commonly used box structure. 2. box beam using steel plate welded into a box structure, with high security, rigidity and other characteristics. Generally used for large tonnage and large tonnage gantry crane. Such as the right MGhz1200, from the weight of 1,200 tons, is the largest gantry crane, the main beam with a box beam structure. Box girder also has high cost electric single girder overhead crane, self-important, poor wind resistance and other shortcomings. 3. Cellular beams are generally referred to as "castellated beams isosceles triangle," the Ends of the main triangle, honeycomb holes on both sides of the oblique abdominal, upper and lower portions have a chord. Cellular beams and joists absorb the characteristics of cantilever box girder cranes, representing joist have greater stiffness, small deflection crane manufacturers, the reliability is higher. However, due to the use of welded steel, the weight and the cost is slightly higher than the joist. Applicable to the use of frequent or large venues or lifting beam field. Because of this beam type is the patented product, thus producing fewer manufacturers. Electric single-girder overhead crane, Zhongshan cranes, heavy generous generous by heavy machinery Co., Ltd., Henan Province. Heavy Machinery Co., Ltd., Henan Province, generous (www.hnqizhongshebei.com) (www.hnqizhongshebei.com) strong, credible, in Zhengzhou, Henan engineering, construction crane industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving generous innovative ideas will lead into the brilliant heavy and you work for a better future!