| 摘要 |
A tower crane contains a running frame with a rotating platform located on it, a tower, which consists of separate sections, with a device for installation of crane and a saddle jib made from three-dimensional sections connected together by inserts and fixing elements located at the ends of the belts of sections, on which a load trolley is installed, which contains the frame with transverse and longitudinal beams, vertical and horizontal rollers, blocks enclosed by load rope, and equipped with support for load rope, and device for fixation of load rope at horizontal position of jib located in the basic part of the jib, which is made with possibility of turning in vertical plane. In the load trolley the blocks are installed on the brackets fixed on the cross beams of the trolley frame. The axes of brackets are located on the bisector of the angle formed by rope, and passing through the center of the weight of section of cross beams frame. The belts of adjacent sections of saddle jib are made with decrease of cross section toward the end and are installed with eccentricity relative to each other. The insert of each joint is also made with variable section, which corresponds to the internal cavities of belts. Device for securing of load rope includes hingedly attached on the jib of hook gripper connected by hinged thrust with the tower, in lower part of which the device for installation of the crane is installed, which contains a fixed block with guides for displacing the trolley with the aid of extended polyspast formed by assembly rope, which blocks are located from two opposite sides of fixed block fixed block and trolley, they are divided into two groups. Assembly rope is reeved consecutively first to blocks of one of the groups, then to the blocks located from the opposite side of fixed block, and after this to the blocks of the second group. The quantity of branches of assembly rope, which cover each of the mentioned groups, is equal to half of quantity of branches located from the opposite side of fixed block.
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