Patent ID: 8104832

Claim:
A seat comprising: a torsion bar disposed in one of a neighborhood of a front end and a neighborhood of a rear end of a seat cushion section along a width direction; a parallel link mechanism including a first link plate pivotally supported by said torsion bar, a second link plate pivotally supported by the other of the neighborhood of the front end and the neighborhood of the rear end of the seat cushion section, and a connection link plate connecting the first link plate and the second link plate, wherein operational directions of the first link plate and the second link plate are set to almost coincide with a vertical direction along a surface of a seat back section; and a cushioning member supported by said parallel link mechanism, wherein said torsion bar is configured so that a restoring force does not work at a neutral point where no load is applied to said torsion bar, and it is configured so that, when the first link plate and the second link plate operate from the neutral point of said torsion bar in a top dead center direction or a bottom dead center direction, said torsion bar is twisted in one direction or in a reverse direction, thereby making the restoring force to restore the first link plate and the second link plate in a neutral point direction work.