Patent ID: 8360522

Claim:
A vehicle seat comprising: a seatback frame including a pair of side frames; a seat spring mounted between the side frames; a single plate-shaped flexible cushion plate having a back face mounted to the seat spring; a seatback cushion provided in front of the cushion plate; a single plate-shaped flexible auxiliary plate provided between the seatback cushion and the cushion plate and mounted on the cushion plate; wherein the auxiliary plate curves to form a forward bulge when a lower portion of the auxiliary plate moves upward with respect to the cushion plate, wherein the forward bulge retracts when the lower portion of the auxiliary plate moves downward with respect to the cushion plate, and wherein the cushion plate has a vertically extending rib with which the lower portion of the auxiliary plate comes in contact, the vertically extending rib extending from a position below a position on the cushion plate that is opposed to the forward bulge of the auxiliary plate to a position near a bottom of the cushion plate.