Crane with telescopic tower - has rear tie and compensation ropes holding jib permanently horizontal during erection

摘要

The quick-erecting tower crane has an outer tower section attached at the bottom to a slewing platform, and accommodating a sliding inner section supporting the jib, the entire tower and jib being foldable. It has rear tie (2) and compensation ropes (3), attached to the platform (8) before coupling to the rear part of a counterweight unit. The compensation rope is reeved round pulleys so as to form a fall inside the tower before anchoring to the top of the outer tower section (6). The length of both ropes is such that one of them is permanently taut, holding the jib (4) in the horizontal position during the various stages of erection, telescoping, increasing height and assembly.