| 摘要 |
PROBLEM TO BE SOLVED: To provide a liftable column body capable of easily lifting it and restricting its overturning when a gap between an guide cylinder and the liftable column body becomes smaller due to thermal expansion. SOLUTION: A guide cylinder 2 having a hook with groove 21, which is fitted to the inside of an upper end portion of a fixed cylinder 1 embedded in the ground and has a hook with groove, is equipped with a liftable column body 3 which is fitted to the inside of the guide cylinder 2 in a liftable manner and has a projection 4 to stop lifting linked to the hook with groove 21 at a raised position; also projections 6 and 7 are provided for restricting the overturn of the liftable column body 3 by the projection 4 to stop lifting at the center between the lower side and the upper side of the projection 4 to stop lifting. By this configuration, the lifting resistance to the liftable column body 3 can be reduced even though the gap between the guide cylinder 2 and the liftable column body 3 decreases due to the thermal expansion.
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