| 摘要 |
A pair of metal plates sandwich a spacer made of low-friction material and a relatively large diameter circular opening passes through the three members which are held rotatably together by a flared ring or bushing or collar along the edge of the opening. One of the plates is mounted to the floor and a seat is coupled to the other plate. The seat may be attached to a slide carriage comprising one of the aforementioned swivel plates and another rectangular plate, each plate having tracks and rails along parallel outer edges which slidably mate with respectively corresponding rails and tracks on the other plate.
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