Lorry-mounted jib crane - has duplex telescopic jib halves supported in separate brackets with derricking rams below

摘要

A duplex telescopic jib is derricked by a ram about a horizontal axis on the slewing crane superstructure, and the equal telescoping sections are joined by cross-members at the outer ends, the outermost ones accommodating a fly jib between them. Each of the parallel halves of the duplex jib is supported at the base in a bearing bracket with individual bearings. The derricking rams, are mounted below the jib foot pins. The lower links of the rams can be designed also to accommodate a single lattice jib in place of the duplex one, working in conjunction with a derricking gantry pivoting between the bearing bracket, instead of with the fly jib.