三、四联杆铰接组合臂架起升钢绳是沿着杆件(一般都沿拉杆、象鼻梁)从象鼻梁头部通到吊钩的,在变幅过程中,吊钩按照象鼻梁头部的运行轨迹平行移动,因此对象鼻梁头部的运行轨迹进行分析,其结果对吊钩也是适用的。象鼻梁的前后三点1、2、3(图2—1)有两种布置方式:一种是三点成一直线,称 Three or four linkage articulated boom lifting rope is along the rod (usually along the rod, the nose bridge) from the head of the nose to the hook, in the luffing process, the hook in accordance with the nose head Department of the parallel movement of the trajectory, the nose of the nose to track the object for analysis, the results of the hook is also applicable. Trinocular three points before and after 1,2,3 1,2,3 (Figure 2-1) There are two arrangements: one is the three-point into a straight line, said