塔式起重机、升降机的设计、研发、制造、销售、安装、维修、租赁；道路货物运输；建筑机械的销售及租赁；建材、钢材的销售；货物进出口、技术进出口；房屋租赁；计算机软、硬件开发与销售；电机、减速机、制动器的生产、销售；钢结构加工；智能停车设备、立体仓库设备、自动化物流设备的设计、研发、生产、安装、销售及售后维保；停车场自动收费系统的设计、研发；停车场规划设计、建设及经营管理以及其他按法律、法规、国务院决定等规定未禁止和不需经营许可的项目。（依法须经批准的项目，经相关部门批准后方可开展经营活动）
Based on the current situation that the independent height of the tower crane is further raised,the building is far from the center of the tower crane,and the requirements for the length and stability of the attachment rod of the tower crane are increasing,the key factors such as the length of the tower crane cantilever,load condition,attachment distance and attachment rod orientation are taken into account,and combined with the action factors of wind load,a general force analysis model is given based on the mechanical theories such as theory of steel structures and mechanics of materials to calculate the internal force of each rod of the three-rod attachment rod.According to the mechanical theory of the attachment rod and engineering calculation examples,it is concluded that the factors affecting the stability of the attachment rod include the cross-sectional shape,the slenderness ratio and the stay rod installation angle of the attachment rod,etc.By calculating the stiffness,strength and overall stability of the super-long equal-section type attachment rod,the correctness of the mechanical analysis is verified.
In order to improve the reliability of bolt joint design,for the high strength bolts commonly used in the engineering lifting appliance industry,the performance and characteristics of two types of highstrength bolt joints,slip-critical joint and bearing-type joint,are analyzed,as well as the calculation methods of design values of tensile and shear capacities.The calculation methods of the two types of bolt joints are studied and analyzed,and the effectiveness of the calculation methods is verified by practical examples.
In order to enhance the load-bearing capacity of the counter-jib lug of the flattop tower crane and improve its stress condition,on the basis of the stress analysis of the lug,the tension of the tie rod,the position of the lug axis and the angle between the counter-jib and the tie rod are determined in line with the actual operating conditions of the crane.On this basis,the strength of the lug is calculated,and ANSYS is applied for finite element analysis of the lug to obtain the stress distribution law of the lug,and the structure optimization and design of the original lug are carried out.After theoretical calculation,the overall strength of the optimized lug meets the requirements,the stress distribution is uniform,and the stress state is improved.
