| 摘要 |
A swivel chair having a non-keywayed main screw rotatably connecting the chair seat and a supporting base to enable rotational movement of the seat with respect to the base. The top portion of the main screw is secured to the bottom of the seat, and the bottom portion is contained in the base for rotation therein. A ring shaped member, formed of a high coefficient of friction material such as rubber, is mounted on the screw at a position above the base. A nut is mounted on the screw and has a threaded portion the bottom of which comes in contact with the ring shaped member which is in turn rotatably mounted on the base by a washer formed of Teflon or similar low friction material. During normal rotation of the seat and thus the screw, the ring shaped member serves to grip the nut and rotate it with the screw, thereby keeping the seat at a constant vertical position. Relative rotational movement of the screw and the nut, which is accomplished manually, causes an effective raising or lowering of the vertical position of the seat relative to the base.
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