| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent falling out of a pipe shaft in spite of performing an operation of pulling out the pipe shaft in a walking supporting pole of an extensible type consisting of an extensible bar pipe assembly in which a plurality of pipe shafts of a small-diameter side are put into a pipe shaft of a large- diameter side in the state of being capable of successively putting in and out. SOLUTION: In the neighborhood of the base end part of a pipe shaft of a small-diameter side 6 always fitted to a pipe shaft of a large-diameter side 4, a locking piece 20 biased outward in a radial direction, which retractably projects from a hole part 6a formed peripherally, is provided. Then, in the neighborhood of the tip of the shaft 4, a hole part 4h with which the locking piece is engaged is provided. In addition, a sleeve 10 covering a level difference part with the pipe shaft of the small-diameter side is fixed to the tip of the pipe shaft of the large diameter side. A recess part 10c preventing the falling out of the pipe shaft of the small-diameter side by engaging the locking piece of the small-diameter side is formed on the inner peripheral surface of this sleeve. Then, the part 10c is an annular groove and has a tapered slope which reduces the depth of the part 10c with moving toward the pipe shaft of the large diameter side. |
