| 摘要 |
A chair includes a base and a seat each having two side tracks and a front track. Three pairs of pivotal bars have upper ends coupled to the tracks of the seat and have lower ends coupled to the tracks of the base. The bars may expand and fold when the seat moves up and down relative to the base. A tube is extended in the base, the seat includes a downward extending rod slidably engaging in the tube and threaded with a bolt. A motor is coupled to the bolt for driving the bolt and for moving the seat up and down relative to the base to adjust the height of the seat relative to the base.
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