| 摘要 |
<p>The rotary tower crane which folds up completely for transport has a telescopic section (6) which is first swung from a horizontal position to a vertical position at the start of erection. The jib, which is in two parts (13, 13') attached by hinges, can then be swung outwards from a vertical folded position. This extends at right angles from the top of the vertical tower formed by the telescopic section, when fully erected, and carries a travelling crab (11). The cable system uses a winding drum and a set of cables with a large number of pulleys forming one set of strands (10) for operating the crab and load lifting and another set of strands with an upper set of pulleys (22) and lower set (14) for erection. These are interconnected by a connection with a bridging member (7) which is locked to the tower during erection.</p> |
