Patent attributes
An adjusting device of a chair backrest includes a movable base, a connecting block and a positioning unit. The movable base encompasses an adjusting opening having plural continuous V-shaped grooves in two vertical sidewalls, a stopping groove and a projecting-downward portion, and two sliding rails. The connecting block is fitted in the movable base, possessing a rectangular recess. The positioning unit is installed in the rectangular recess, having two upholding feet fixed with the connecting block and respectively having a locking projection and a locking groove corresponding to each other. A spring is put between the upholding feet to elastically expand them. With the movable base fixed with the backrest and the connecting block fixed with a connecting rod, the movable base can be moved up and down together with the backrest, with the height of the backrest adjusted.
