Patent ID: 8668263

Claim:
A vehicle seat comprising: a seat back frame; a collision sensor provided to the seat back frame, and said collision sensor being movable backward when a seat occupant of the vehicle seat is moved relatively backward to the seat back frame by a rear-end collision; a headrest attached to the seat back frame and being movable between a normal support position and a head protection position anterior to the normal support position, and said headrest being movable from the normal support position to the head protection position when the collision sensor is moved backward; and a lock mechanism attached to the seat back frame, said lock mechanism including a locking member that is moved to a lock position by inertia when receiving an external force by the rear-end collision to regulate a return of the headrest from the head protection position to the normal support position; wherein the lock mechanism has a return spring to make the locking member disengage from the lock position, and the locking member is configured to move to the lock position by inertia against an elastic force of the return spring at the time of rear-end collision, and wherein the lock mechanism has a touching spring to bias the locking member in a direction opposite to the return spring, the touching spring having an elastic force stronger than that of the return spring, and the locking member is held at a withdrawal position by touching the headrest when the headrest is at the normal support position, and the touching spring makes the locking member at the withdrawal position touch the headrest elastically.