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 Crane Rental, aimed a greater lateral space cranes to the goods passed legs. 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. L-type L-type hook gantry crane gantry crane which is mainly composed of the door frame, lifting the car, traveling mechanism, cab and electrical control system. Mast box-shaped structure electric single girder overhead crane, from the weight of the car when 20t or less vertical trans roller, is greater than the level of anti-20t car used roller, running on the side of the main beam, the main beam off-track in the form of a single-girder crane , L-shaped legs, big lifting space, over cross-ability, easy to transport from a cross inside the object to the next boom. Operation with closed cab, there are adjustable seats, floor mats laying insulation, windows with tempered glass, equipped with fire extinguishers, fans, heating and air conditioning can be configured, Xiangqi, walkie-talkies and other items according to user requirements. Heavy cranes _ generous (certified) _ Crane Co., Ltd. Nanning provided by generous heavy machinery in Henan Province. Heavy Machinery Co., Ltd., Henan Province, generous (www.hnqizhongshebei.com) (www.hnqizhongshebei.com) is Zhengzhou, engineering, construction cranes leaders, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum Limits to meet customer needs. In heavy generous leadership with the staff warmly welcome all inquiries negotiations to create a better future for heavy generous.