Crane jib head sheave with extension pulley - is attached to lever to maintain effort on jib in line with cable tension

摘要

The crane jib head (2) is fitted with a pulley (3) which guides the cable (13). The pulley has a lever (37) mounted on the same axis and the lever carries a second pulley (38), so that it can oscillate on the support bracket (4). The support bracket can rotate on the jib head about the longitudinal axis (14) parallel to the jib axis. The bracket is attached to the jib through a bearing (30), with a fixed sleeve in the bore of the jib. The bearing is made up of two coaxial elements, one inside the other. The inner element is fixed to the jib head and the outer is fixed to the support bracket. The two elements are mounted so as to be able to rotate w.r.t. one another.