Patent ID: 7819473

Claim:
A chair comprising: (a) a base portion; (b) a first link fixed to a seat and rotatably connected to the base portion; (c) a second link fixed to a seat back rest and rotatably connected to the first link; (d) a first torque-generating mechanism that generates torque in accordance with the angle of the first link relative to the base portion; (e) a second torque-generating mechanism that generates torque in accordance with the angle of the second link relative to the first link; and (f) an added torque-generating mechanism including an elastic body connecting the base portion and the second link, and that simultaneously generates torque, which acts on a joint that connects the base portion and the first link, and torque, which acts on a joint that connects the first link and the second link in accordance with the angle of the first link relative to the base portion and the angle of the second link relative to the first link.