| 摘要 |
A vehicle seat comprises a seat pan, a backrest pan, and a pair of connector plates connected to opposite lateral sides of the seat pan. Backrest height adjustment means are connected between the connector plates and the backrest pan to enable the backrest pan to be raised or lowered vertically to desired positions relative to the seat pan wherein it then becomes locked. The backrest height adjustment means comprises: a pair of spaced apart brackets connected to the backrest pan, each having a vertical track and a vertical guide slot, a rotatable control rod extending through the guide slots and having a pair of track sprockets fixed thereon and engaged with the vertical tracks, planocentric gears, including a spur gear fixed to one end of the control rod and a ring gear having internal teeth engaged with the spur gear and fixed to one of the connector plates, an eccentric pin rotatable by a height adjustment knob located outside of the connector plate and having eccentric cylindrical portions, said pin engaged with a circular hole in the spur gear and with a circular hole in the connector plate, whereby knob rotation causes slight harmonic travel (oscillation) and rotation of the spur gear and corresponding rotation of the control rod sprockets along the tracks to cause vertical motion of the backrest pan. A stop member on the spur gear is engageable with stop pins on the ring gear to limit vertical travel. A slideable connection is provided between the other connector plate and the backrest pan.
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