| 摘要 |
<p>A device for adjusting the height of the back-rest of a seat back portion, in particular in office chairs, characterised by comprising: a guide element (9, 34) rigid with the support plate of the seating portion (6), for supporting the back-rest (8), a slide (17, 30) engageable with said guide element (9, 34) and slidable along it, means (18) rigid with said slide (17) (said guide element 34) which are engageable elastically and selectively in the teeth of a toothed portion (11) provided on said guide element (9) (said slide 30) to ensure the stability of the position of said slide relative to said guide, said elastic means (18) being able to slide freely along the passive flanks of the teeth of the toothed portion (11, 32) during the raising of the back-rest, and being locked by the active flanks after each passage over a tooth, said elastic means (18), following their elastic reaction and for a predetermined position of said slide (17, 35) relative to said guide element, being disengageable from said teeth to hence enable said slide (17, 30) to slide by gravity relative to said guide element (9, 34).</p> |
