Backrest height adjustment for office chair

摘要

A housing is fixed on the backrest and supports the same for vertical sliding movement on the upper end portion of a vertical support member. Notches are spaced vertically along the upper portion of the support member and a pawl is pivotally supported on the housing and includes a ratchet finger movable between an operative position with the ratchet finger in engagement with the notches and an inoperative position with the ratchet finger out of engagement with the notches. A spring is associated with the pawl and is operable to selectively maintain the pawl and ratchet finger in either the operative or inoperative positions. When the backrest is raised to the uppermost adjusted position, the pawl; is switched to the inoperative position and the backrest may be freely lowered to the lower end of the adjustment limit in preparation for a subsequent adjustment in the upward direction.