US Patent 11180056 Vehicle-mounted seat device

A vehicle-mounted seat device includes an SB main frame, a backrest, a relay disk secured at the center in the width direction of the backrest, a plurality of radial wires for suspending the backrest such that the backrest can swing relative to the SB main frame with the relay disk as the center, an SB subframe capable of swinging together with the backrest, a headrest, a headrest stay extending downward from the headrest and mounted on the SB main frame so as to rotate around a rotation shaft; a pressure-receiving body secured on the headrest stay so as to be disposed behind and opposed to the relay disk; and a provisional connection mechanism for provisionally connecting the headrest stay to the SB main frame.