| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotational positioning structure for legless chair.SOLUTION: An annular ring 3 having concave parts 31 circumferentially provided thereon is provided in a space above a sleeve 2 attached to an upper part of a gas pressure cylinder 1. A rod step portion 5 having a spring 52 connected thereto is provided on a pipe step portion 22. A notch opening 61 on one end of a top contact fitting 6 which is fitted into a concave hole 71 of an operation knob 7 is fitted to a convex portion 23 of the pipe step portion 22 of the sleeve 2, and then a screw 73 is screwed into a hole 72 of the operation knob 7, thereby fastening the spring 52 to one end of the fittingly provided rod step portion 5. When the operation knob 7 is not rotated, the rod step portion 5 inside the pipe step portion 22 at one end of the sleeve 2 is subjected to a directional restriction of the operation knob 7, and is inserted into the concave portion 31 of the annular ring 3 inside the sleeve 2 to exert a directional restriction. When the operation knob 7 is rotated, the rod step portion 5 is retracted from the concave portion 31 of the annular ring 3 by a movement of the operation knob 7, and the legless chair can thereby be rotated in direction. |
