| 摘要 |
PROBLEM TO BE SOLVED: To weaken hitting when housing an aerial sheave unit in a pair of housing support members without lowering work efficiency.SOLUTION: A drive mechanism for an aerial sheave unit 14 derricking a luffing jib mounted to the tip of a telescopic boom in a crane working vehicle include a controller 45 winding a jib wire 15 wound around the aerial sheave unit 14, by a jib winch 12 to house the aerial sheave unit 14, and a mechanical switch 41 detecting the housed aerial sheave unit 14. When the housed aerial sheave unit 14 is detected by the mechanical switch 41, the controller 45 determines whether the crane working vehicle 1 is in a housed state, and decelerates winding of the jib wire 15 by the jib winch 12 when the crane working vehicle is in the housed state but does not decelerate winding of the jib wire 15 by the jib winch 12 in a state other than the housed state. |
