Tower crane crab rope reeving system - has further double pulleys at hinge between folding jib sections

摘要

The rope-reeving system is for the crab of a tower crane with a folding jib, the rope being fixed to the crab and wound several times round a winch drum. At the jib hinge there is a frame joining its two sections together. The rope is reeved round further double pulleys (12, 12'), the longest run here being at least as great as the maximum space required by the jib in the transverse direction when folded. The pulleys can work with opposite cable runs, while a third one (14) is mounted at the end of the frame (13). The run of rope between these two pulleys and the third one is as long as the distance between the undersides of the jib sections when folded, plus the distance between the two pulleys and the third in this position.