| 摘要 |
PROBLEM TO BE SOLVED: To enable a boom erecting operation when a hook is stored. SOLUTION: This crane comprises a boom telescoped and elevated by a boom telescoping cylinder 13 and a boom elevating cylinder 14, respectively, and a winch hoisted up and down by a winch motor 15 and stops each operation of hook hoist up, boom extension, and boom erection when the a hook is overwound. In this case, the crane further comprises a hook storing switch valve 45 for performing a hook storing operation to hoist up the hook in the state of being overwound and a hook releasing operation to lower the hook and a boom erecting switch valve 44 for erectedly operating the boom according to the hook storing release operation of the hook storing switch valve 45.
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