Patent attributes
A headrest includes a reverse input blocking clutch and a displacement mechanism. The reverse input blocking clutch includes input and output shafts that respectively receive and output rotational torque, an outer ring and a side plate in which rotation is restricted, cylindrical rollers that control blocking of the rotational torque reversely input from the output shaft and transmission of the rotational torque from the input shaft through engagement and disengagement between the outer ring and output shaft, and a cage to retain the cylindrical rollers. The displacement mechanism has one end fixed to stays and another end fixed to a headrest main body positioned at a top of a seat back, and displaces the headrest main body through the rotational torque from the output shaft of the reverse input blocking clutch. The another end of displacement mechanism has the side plate of the reverse input blocking clutch mounted thereto.
