| 摘要 |
PROBLEM TO BE SOLVED: To provide an expansion device of a telescopic boom, which can improve operability of the telescopic boom while achieving cost reduction, and can achieve efficient insertion work as well as reduction in assembly man-hour.SOLUTION: An expansion device 3 of a telescopic boom 1 comprises an expansion cylinder 4 for expanding and contracting a second boom 22, and an expansion mechanism 5 for expanding and contracting a top boom 24 and a third boom 23 simultaneously while interlocking with the expansion/contraction operation of the expansion cylinder 4. The expansion mechanism 5 comprises a rod-like support member 10. The rod-like support member 10 is disposed inside the top boom 24 while its one end side is fixed to a base end side inside the third boom 23. The rod-like support member 10 is formed so as to be built inside the top boom 24 while a top boom expansion sheave 71, (71) is disposed at a distal end side. A top boom contraction sheave 91, (91) is disposed at a base end side of the rod-like support member.SELECTED DRAWING: Figure 1 |
