| 摘要 |
PURPOSE:To obtain a lifting/lowering device capable of being kept in a perfectly locked state both in the upward and downward directions by providing two rings of the upper and lower rings which have been inserted in a pipe inside a stand part and cam parts at two places which operate the one of two rings at the operating part of ring. CONSTITUTION:A lower ring 1 is provided beneath an upper ring 105, and has a long length when measured from the center of inside diameter to the end face of the ring in the direction of operational knob 3, and is not engaged to be locked with a spring 104. On the half of the end face of the knob 3 a cam 3a extending in the horizontal direction is provided, and on the other half of it another cam 3b extending in the vertical direction is provided. And it is so constituted that only either of the both cam parts can be operated. Thus, the locked engagement of pipe can be ensured both in the upward and downward directions.
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