| 摘要 |
PROBLEM TO BE SOLVED: To provide a holding mechanism for a telescopic mast that can hold all the masts of each stage in the middle of being telescoped.SOLUTION: The holding mechanism for a telescopic mast includes: gate bar mechanisms 20 each of which is provided in the outer peripheral side of each of apexes of the lower mast 2 and the intermediate masts A, B and has gate bars 26 that freely exit and enter the inside of each mast and actuates so as to hold the mast A, B or 1 when the gate bars 26 enter each mast, while not to hold the mast A, B or 1 when the gate bars 26 exit each mast; and a changeover mechanism 22 which 22 switches the operation state of each gate bar mechanism 20. The changeover mechanism 22 includes telescopic sheath pipes 28a, 28b that extends vertically along the outer peripheral side of the masts 2, A, B and follow the telescopic motion of the mast mechanism, and the changeover mechanism 22 can change over the operation state of each gate bar mechanism 20 in conjunction with each other by operating these sheath pipes 28a, 28b so as to turn around the tube axis. |
