Telescopic tower crane with folding jib - has rope to jib head unfolding jib automatically on tower extension

摘要

The crane has a telescopic tower with fixed and moving lattice-work sections, also a jib with head section hinging on the foot section and the latter derricking on the top of the moving tower section. A constant-length rope (14) is reeved from the jib head section to a point on the fixed (6) or moving (7) tower section and round pulleys (16, 8) on the jib foot section (9) and the tower sections, in such a manner that the jib is fully folded and unfolded as the moving tower section is extended and retracted.