Chair height adjustment mechanism

摘要

A control assembly for adjustable displacement of a chair seat or the like comprises a lead screw threaded to a nut for relative longitudinal movement in order to adjust the height of the chair with the relative movement of the screw and nut. The control assembly also includes a rotational bearing for swiveling the seat while maintaining the desired seat height; the rotational bearing also allows backdriving, for example rotation of the screw, without rotation of the seat. The control assembly also includes a locking mechanism for selectively preventing relative movement of the screw with respect to the nut in order to maintain the desired seat height. A power spring can be provided on the assembly to drive selective elevation, for example of the screw and seat, when the screw has been unlocked.