US Patent 7445283 Headrest height adjusting apparatus

A headrest height adjusting apparatus includes: a basal member attached to a seatback and supporting a driving member; a movable member linked to a headrest and lifted up and down relative to the basal member; a transmitting member transmitting a driving force of the driving member to the movable member and lifting up and down the headrest linked to the movable member. The transmitting member having a frangible portion that leads a collapse of the transmitting member against an impact applied in a vertical direction between the driving member and the movable member and absorbs energy of the impact.