Design Theory Of The Odd-even Ratios Hook-device For Luffing Jib Tower Crane

With the density of city buildings increasing, skyscrapers of steel structure manifolding, and many cranes having to work together, etc, large and medium luffing jib tower cranes are being used more and more. Owing to being limited by rope quantity of hoist mechanism, large and medium luffing jib tower cranes adopt commonly the 1-2 ratios hook-device. Due to relating to odd-even ratios, it is difficult to accomplish the ratios transform semiautomatically and automatically. Therefore, studying and seeking after the odd-even ratios hook-device that can transform ratios semiautomatically or automatically have great practical value to the crane industry.Aimed at designing and studying the odd-even ratios hook-device, and based on summarizing the correlative knowledge of the ratios transform and analysing study actuality of the ratios transform device, the dissertation studies this hook-device's structure design, movement analysis, statics analysis, stability analysis, dynamic analysis, etc. The creative contributions are summarized as follows.1. For the first time, the correlative knowledge of ratios transform and the study actuality of the ratios transform device were summarized. The definition of the hook-device's ratio is given. And the computing formula of the ratio is described.2. The structure design of the odd-even ratios hook-device is finished. For the first time this device accomplishes semiautomatically the odd-even ratios transform through the structure.3. The hook-device's movement curves are analysed in different work-modes of luffing jib tower crane. In even ratio the device's movement curve with rope rising is pictured near the top of the jib. It provides a theory basis and the data information for control problem of speed and hoist position when transforming ratios. The movement process of the hook-device transforming ratios is anatomized. The movement curve is drawed. It prove rationality and feasibility of the hook-device.4. The hook device's planar forces are analysed using planar elastic mechanics theory. Inside-plate is carried out finite element analysis. The deformed picture and the stress distributing picture are described. According to special forced method, inside-plate subassembly is carried out buckling analysis making use of plate-shell's stability theory. The finite element model of the plate-beam structure is established. The buckling loads and the modes are obtained.5. Inside-plate subassembly is carried out mode analysis. Its dynamics model is built. Natural frequencies and mode shapes are obtained. Whereafter, Inside-plate subassembly is performed dynamic analysis. Displacement graph of the node on the forced plane is drawn. It represents fluctuant curve visually that the inside-plate's forced plane is going with dynamic load.In this dissertation, the odd-even ratios hook-device is designed for D800/50 luffing jib tower crane. But its structure and principle of the ratios transform are applicable completely to other crane, and have great practical value. The research result in theory of this dissertation will lay a solid foundation for the in-depth study of the odd-even ratios hook-device.