Study On The Key Techniques Of Luffing Jib Cranes

The luffing jib way is widely used in various types of cranes, such as offshore cranes, ship cranes and tower cranes. In the design of these cranes, there are some key technologies, such as how to determine the length of truss joint of the chord; the three pin-connected joints coordinates of the luffing system and the method to calculate the lifting performance and so on. While in the previous journals, there are some discuss to some specific issues, the research method is complex, which is not aimed at the overall design of the crane, whose conclusions are not be well applied to the actual design, so there are some limitations.In allusions to the issues mentioned above, some key techniques are to be studied systematically in this paper in the mechanical point of view, which is a reference to the design of this kind of the cranes. The main research and the results of the paper are as follows:(1)The realization form of movable-counterweight is summed and the change law of the movable-counterweight center of gravity position and the boom angle is found out. In the end of this section, take the form of wire rope as an example, the factors considered in the design of the movable-counterweight are described, which provides a reference to the design of movable-counterweight in tower cranes.(2) Considering of the strength and stability of the ideal compressed bar, actual compressed bar and compression bending bar in two-way, the method to determine the length of truss joint of the chord is derived in the mechanical point of view. In the same time, the biggest axial pressure to a given component is derived, which provides a reference to the design of the truss-type jib system.(3) Considering of the actual force to the components, the relationship of the three pin-connected joints coordinates of the luffing system and the force to them is derived in the mechanical pin-connected joints of view. We can use simple mathematical relationship to pre-judge whether the pin-connected joints coordinates are rational, which can avoid the debugging process in the optimal design and provide a reference to the design of luffing system.(4) Luffing jib cranes aided design system is developed, whose main task is to check the structure and compute the lifting performance of all this kind of cranes. This system is suitable for the structure design of any luffing jib cranes and it contains the complete analysis process for various kinds of codes. At the same time, take TCR6055-32, cooperating between DUT and Zoomlion, as an example by FEM to reason the correctness and feasibility of the method proposed, and the practicability of the soft developed.