Abstract: A backrest frame 5 is provided with a cushion plate 31 of one substantially square plate form positioned behind the waist from the upper part of the back of a vehicle seat occupant, movably back and forth by way of a plurality of upper and lower parallel seat springs, one end of either one of a pair of right and left seat springs 34B of the plurality of upper and lower parallel seat springs is connected to a pair of lower link mechanisms 35 provided rotatably on the backrest frame 5, and a rear end collision sensor 40 is formed by the cushion plate 31 between the seat springs 34B for moving a headrest 4 forward, and a coupling part 39 of the other end of the seat spring 34B is directly attached to the lower link mechanism 35.

Abstract: A vehicle seat of the invention has an upper movable member (10) supporting a headrest (3), a lower movable member (30) provided inside a backrest, and a coupling mechanism for coupling the upper movable member and the lower movable member. The coupling mechanism includes an upper link mechanism (15) positioned in an upper part of a side frame (40) and coupled to the upper movable member, a lower link mechanism (32) positioned in a lower part of the side frame and coupled to the lower movable member, and a rod (27) extending along the side frame and coupling the upper link mechanism and the lower link mechanism. The upper link mechanism amplifies a backward moving amount of the lower movable member, and moves the headrest forward.

Abstract: A vehicle seat of the invention includes: a rectangular-shaped seat back frame (5) having a pair of side frames (6); a plurality of seat springs (34A, 34B) disposed between the side frames; a single plate-shaped flexible cushion plate (31) attached to the seat springs; a seat cushion (9) provided on the front side of the cushion plate; link mechanisms (15, 35) provided near the side frames; and a headrest (4) coupled to the link mechanisms (15). Both ends of the seat spring (34B) are coupled to the link mechanisms. When the seat spring (34B) is moved rearward, the headrest is moved forward. Both sides of each of the remaining seat springs (34A) are mounted to the side frames.