Patent ID: 6840581
Filing Date: 2005-01-11
Classification: A47C

Abstract:
1. A height adjustment mechanism mounted in a chair, comprising: a horizontal recess in a rear side of a backrest, the recess having a central, cylindrical hole; a resilient element anchored in the hole; a substantially T-shaped trigger member inserted in the recess for biasing against the resilient element, the trigger member comprising a horizontal section having a projecting finger tab located between two spaced portions; a plate releasably secured onto the recess, the plate having a central, horizontal slit, with the finger tab and the two spaced portions of the trigger member through the horizontal slit; two upright tubes on opposite sides of a vertically stationary upright backrest support which is attached to a backside of the backrest and an underside of a seat, with the two upright tubes being below the recess; an inverted U-shaped rod having two vertical rods, with each of said vertical rods including a plurality of notches in a forward side facing the backrest, the finger tab being disposed between the vertical sections of the rod, and with the two spaced portions in the horizontal section of the trigger member being simultaneously received in two notches in a non-operating position; and a predetermined member mounted on a top of the rod, wherein pushing of the finger tab moves the T-shaped trigger member into the recess towards the backrest and compresses the resilient element until the spaced portions in the horizontal section of the trigger member clear from the notches, raising or lowering of the rod while continuously pushing the finger tab moves the rod relative to the trigger member until a desirable height of the rod is reached and the finger tab is aligned with two other notches, and releasing of the finger tab causes the trigger member to bounce rearward for moving the spaced portions in the horizontal section of the trigger member in the two other notches for fastening the inverted U-shaped rod to the backrest again.