Patent ID: 8100473

Claim:
An automobile seat including a seat cushion having a seat cushion frame, a seat back tiltably mounted on the seat cushion, and a headrest mounted on an upper portion of the seat back, said automobile seat comprising: a seat back frame having a pair of side frames mounted on the seat cushion frame and a sub-frame mounted to the side frames via a hinge so as to be swingable with respect to the side frames; a pressure member mounted on a lower portion of the sub-frame; and a swinging motion restraint mechanism for restraining a swinging motion of the sub-frame relative to the side frames, said swinging motion restraint mechanism comprising a swing axis mounted on the sub-frame and swingable between a forward position and a rearward position, and an elastic member for biasing the swing axis; wherein in an initial state in which no load is applied to the seat back, the swing axis is held at the forward position by an elastic force of the elastic member, and in a normal sitting condition in which a load less than a predetermined value is applied to the seat back, the swing axis is swingably held by the elastic force of the elastic member; when a load greater than the predetermined value is inputted to the seat back in a rearward direction, the pressure member is moved rearward to thereby move the swing axis rearward against the elastic force of the elastic member, swing the sub-frame about the hinge, move the headrest forward, and hold the headrest at a position after the movement by the elastic force of the elastic member; and wherein the seat back can be returned to the initial state by applying a force to the sub-frame against the elastic force of the elastic member.