Patent ID: 7445283

Claim:
A headrest height adjusting apparatus comprising: a basal member to be 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: and 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 to a collapse of the transmitting member in response to an impact applied in a vertical direction between the driving member and the movable member and absorbs energy of the impact, wherein the transmitting member further includes: a transmitting member body engaged with an input member of the movable member and transmitting the driving force of the driving member to the input member,, and a metal-made core, which is inserted into the body part, facing the input member in the vertical direction.