Patent ID: 8109567

Claim:
An active headrest adapted for use with a seat, and to selectively support the head of an occupant, said headrest comprising: an exterior shell defining an interior space and outer surface configured to engage the head of the occupant; an actuator disposed within the space, and operable to adjust the distance or engagement between the surface and head, wherein the actuator includes a bar linkage system presenting at least one selectively deployable swing arm pivotally coupled to the seat and shell, and further includes an active material element drivenly coupled to the arm, so as to selectively cause or enable the arm to pivot, when the element is exposed to or occluded from an activation signal; and a power source communicatively coupled to the actuator, and operable to generate the signal, wherein the actuator further includes a selectively engaged ratchet and pawl cooperatively configured to allow the headrest to translate in a first direction and prevent translation in the opposite direction when engaged, the ratchet defines a channel section having a distal depression, the pawl includes a cam configured to slidingly engage the channel during translation in the first direction, and the channel and cam are cooperatively configured to cause the ratchet and pawl to disengage, so as to allow translation in the opposite direction, when the cam engages the depression.