Patent attributes
A chair backrest adjusting mechanism includes a seat supporting frame, a backrest supporting arm, amount, a supporting arm cover, and a ball-shaped handle. The seat supporting frame is fixedly connected at a lower end to a base below a chair seat, and pivotally connected at an upper end to two pivot brackets at a lower end of the backrest supporting arm, which is further pivotally connected at an upper end to the mount on a rear side of a chair backrest. The supporting arm cover is fitly covered on the backrest supporting arm with upper and lower ends pivotally connected to the mount and the upper end of the seat supporting frame. A threaded rod is fixedly mounted in and turned via the ball-shaped handle to drive the backrest supporting arm to tilt forward or backward, and accordingly adjust the backrest to different positions relative to the chair seat.