Patent ID: 6726280
Filing Date: 2004-04-27
Classification: A47C

Abstract:
A mechanism for adjusting the height of the back support of a chair comprising:a frame being mounted on a rear portion at a bottom of a chair seat, a back support, a first link pivotably connecting to said frame at a top thereof and a rear wall of said back support, and a second link pivotably connecting to said frame at a top thereof and said rear wall of said back support, said second link being in parallel to said first link; a lower pivotal point at which an end of said first link and said frame connect and a lower pivotal point at which an end of said second link and said frame connect being arranged in a way that a line defined by said lower pivotal points is oblique to the horizontal direction at a definite angle, an upper pivotal point at which the other end of said first link and said rear wall of said back support connect and an upper pivotal point at which the other end of said second link and said rear wall of said back support connect being arranged in a way that a line defined by said upper pivotal points maintains a constant oblique angle to the horizontal direction during a process of changing said back support's height; said back support therefore being held vertical during said process.