| 摘要 |
PROBLEM TO BE SOLVED: To prevent a worker from forgetting to remove a spacer of a back stop when shifting to usual work after lifting work by his/her own physical strength and forgetting to pull out a gantry cylinder mounting pin when performing the lifting work by his/her own physical strength. SOLUTION: This crane is constituted in such a way that the spacer 19 for preventing contraction action of a back stop main body 15 when mounting and dismounting a counterweight by his/her own physical strength is formed into a U-shape, the spacer is attached to an outer pipe 14 so as to turn between a set position where it is fitted into an inner pipe 13 by using its front side as a fulcrum and a position where it turns downward and forward and leaves the inner pipe, and the spacer turns from the set position to the leaving position by its self-weight by elongation and forward inclining operation of the back stop main body operating in the interlocking relationship with forward falling-down of a boom when shifting to usual work after counterweight mounting work by his/her own physical strength. The mounting pin 22 of a gantry cylinder 6 is commonly used as a main body fixing pin for preventing elongation action of the back stop main body 15 when mounting and dismounting the counterweight by his/her own physical strength. COPYRIGHT: (C)2007,JPO&INPIT
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