Abstract: 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.

Abstract: 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.

Abstract: In a vehicle seat system equipped with an active headrest mechanism (30) and a lumbar support (21), a load-receiving part (32) of the active headrest mechanism (30) is positioned behind the lumbar support (21) as viewed from front of the seat. The vehicle seat system is arranged so that when a specified amount or more of load is applied from front of the seat to a lumbar support plate (22) of the lumbar support (21), one end part of a plate support member (23) supporting the lumbar support plate (22) exits from an insertion hole (17) provided at a side frame (4) to disengage from a seatback frame (2), and the disengaged end part of the plate support member (23) then abuts on the load-receiving part (32).

Abstract: In a vehicle seat system equipped with an active headrest mechanism (30) and a lumbar support (21), a load-receiving part (32) of the active headrest mechanism (30) is positioned behind the lumbar support (21) as viewed from front of the seat. The vehicle seat system is arranged so that when a specified amount or more of load is applied from front of the seat to a lumbar support plate (22) of the lumbar support (21), one end part of a plate support member (23) supporting the lumbar support plate (22) exits from an insertion hole (17) provided at a side frame (4) to disengage from a seatback frame (2), and the disengaged end part of the plate support member (23) then abuts on the load-receiving part (32).