| 摘要 |
PROBLEM TO BE SOLVED: To provide a telescopic device of a telescopic boom in which operability of the telescopic boom can be improved while reducing a cost, an insertion work can be efficiently performed, and a cross sectional area of the entire telescopic boom can be limited to a minimum required area.SOLUTION: A telescopic device 3 of a telescopic boom 1 comprises: a telescopic cylinder 4 which extends/contracts a second boom 22; and a telescopic mechanism 5 which simultaneously extends/contracts a top boom 24 and a third boom 23 while being interlocked with a telescopic motion of the telescopic cylinder 4. The telescopic mechanism 5 comprises: a rod-like support member 10 arranged in parallel with the telescopic cylinder 4; a sheave 71(71) for extending the top boom which is arranged on a tip side of the rod-like support member 10; and a sheave 61 for extending the third boom which is arranged on a tip side of the telescopic cylinder 4. The rod-like support member 10 is formed such that a part of the sheave 61 for extending the third boom is arranged inside the member.SELECTED DRAWING: Figure 1 |
