Crane with auxiliary lifting gear - has small jib at base of crane mast operated by pulley arrangement

摘要

The crane has a cable (B), winch (4) and an auxiliary jib (14) fixed to the vertical mast (1) near the base to handle ballast blocks of concrete. The jib (14) has a lifting cable (A) of constant length, with hooks (17) at one end. The other end is fixed in a moving pulley (6) inside a loop formed by the crane cable (B). Downward movement of the pulley is caused by its weight and upward movement by the cable (B). Movement is limited by a stop (D). The pulley is mounted in a fork (7) to which is fixed part of the auxiliary cable (A).