Patent ID: 7159944

Claim:
A backrest for a chair, comprising: a back support having a top end portion provided with a pivot shaft that has two opposite end portions; a backrest cushion disposed adjacent to said top end portion of said back support and having a rear wall that is formed with a pair of threaded holes; a coupling cover having an open end facing toward said rear wall of said backrest cushion, covering said pivot shaft, and having a back wall that is formed with a pair of counter bores; a pair of screw bolts extending respectively through said counter bores in said back wall of said coupling cover and engaging threadedly and respectively said threaded holes in said rear wall of said backrest cushion so as to drive said coupling cover toward said backrest cushion and to permit abutment of said open end of said coupling cover against said rear wall of said backrest cushion; and a pair of pivoting members, each of which has a pivot sleeve that is sleeved rotatably on a respective one of said end portions of said pivot shaft, and a linkage that extends from said pivot sleeve and that is coupled to a respective one of said screw bolts so as to pivot said backrest cushion together with said coupling cover about said pivot shaft.