Seat lifter device

#The present invention relates to a seat lifter device that adjusts the vertical position of a seat cushion.

#Some of the seats of a vehicle such as the front seats include, for example, a seat lifter device, which allows a seat occupant to adjust the vertical position of a seat cushion in accordance with the size of the seat occupant to obtain a desired eye level. Conventionally, various types of such seat lifter devices have been proposed. For example, a seat lifter device disclosed in Patent Document 1 includes lifter mechanisms, which are mounted on base plates on upper rails. The lifter mechanisms adjust the vertical position of the seat cushion. Brackets are fixed on the base plates, and a seat back is fixed on the brackets via reclining mechanisms. According to this seat lifter device, only the seat cushion moves vertically with respect to the base plates and the seat back.

#In a seat lifter device disclosed in Patent Document 2, the seat cushion is supported on lower frames via front links and rear links that form quadric crank chains. The front links and the rear links adjust the vertical position of the seat cushion. The seat back is fixed on the seat cushion via the reclining mechanisms. According to this seat lifter device, unlike the device of Patent Document 1, the seat cushion and the seat back integrally move up and down.

#FIG. 1 is a perspective view illustrating a vehicle seat to which a seat lifter device according to a first embodiment of the present invention is applied;

#FIG. 2 is a plan view illustrating the seat lifter device of FIG. 1;

#FIG. 3 is an exploded perspective view illustrating the seat lifter device of FIG. 1;

#A first embodiment of the present invention will now be described with reference to the drawings.

#FIG. 1 is a perspective view showing a seat 1, which is a front seat of a vehicle such as an automobile. As shown in FIG. 1, a pair of lower rails 2, which face each other in the widthwise direction of the seat 1 and extend in the fore-and-aft direction, is fixed on a vehicle floor F (see FIG. 4). An upper rail 3 is mounted on each of the lower rails 2 to be movable relative to the associated lower rail 2. The pair of lower rails 2 and the pair of upper rails 3 form a slide mechanism.

#A plate-like bracket 4 (a seat support member), which extends upward, is coupled to each of the upper rails 3. More specifically, as shown by a transverse sectional view in circle C in FIG. 1, each upper rail 3 includes a pair of members 3a, which is formed by bending plate materials that face each other. The pair of members 3a is symmetrical. Each bracket 4 is fastened to a vertical wall formed at the center of the corresponding upper rail 3 with, for example, a bolt and a nut or a swage pin. A seat main body 5 is secured to and supported by the brackets 4 via a lifter mechanism 10. The seat main body 5 includes a seat cushion 6, a seat back 7, which is tiltably (rotationally) supported at the rear end portion of the seat cushion 6, and a headrest 8, which is supported at the upper end portion of the seat back 7. The fore-and-aft position of the seat main body 5 is adjustable by the slide mechanism, and the vertical position of the seat main body 5 is adjustable by the lifter mechanism 10. Thus, a seat occupant of the seat main body 5 adjusts the vertical position of the seat main body 5 in accordance with the size of the seat occupant, for example, to obtain a desired eye level.