| 摘要 |
PROBLEM TO BE SOLVED: To hold a hook suspension length at a constant when a boom is telescoped by interlockingly performing a boom telescoping operation and a winch winding up and down operation. SOLUTION: A crane comprises a boom telescoped by a boom telescoping hydraulic cylinder 8 and a winch winding up and down a hook by a winch hydraulic motor 10. The crane further comprises an extension and winding down interlocking pipe 32 allowing the extension pipe 34 of the boom telescoping hydraulic cylinder 8 to communicate with the winding down pipe 28 of the winch hydraulic motor 10 through an interlocking switching valve 30 and a retraction and winding up interlocking pipe 31 allowing the retraction pipe 27 of the boom telescoping hydraulic cylinder 8 to communicate with the winding up pipe 29 of the winch hydraulic motor 10 through the interlocking switching valve 30. A flow distributing and combining valve 40 distributing and combining flows so that the ratio of a flow on the boom telescoping hydraulic cylinder 8 side to a flow on the winch hydraulic motor 10 side becomes a specified one is installed in the extension and winding down interlocking pipe 32.
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