Tower for tower crane - is assembled from square frames fastened to each other by corner bolts

摘要

The tower of a tower crane is constructed from frames bolted together. Each frame has four corner members which extend vertically. The corner members of one frame (1) have tongues (5) which fit between the side members (7) of the upper frame (3). The two frames are fastened together by a bolt (15) with a stepped diameter. The steps in diameter corresp. to the sizes of the holes (9,11,13) in the two frames. The dia. decrease from the head end (29) to the tapered end (27). The shank of the bolt has a spiral groove (31). USE - Erection of towers of tower cranes.