Vehicle seat with side air bag assembly

Abstract: A vehicle seat equipped with a side air bag assembly (20) the air bag (22) of which is assembled within a side cavity (14) formed in one side of a back rest (10a) of the vehicle seat in a folded condition, wherein a rear attachment board (13) is mounted on a support frame (12) of the back rest, the rear attachment board (13) having a back portion (13c) formed to cover the rear face of the back rest (10a) and a side portion (13d) formed to cover the air bag (22) in the side cavity, and wherein the side portion (13d) of the rear attachment board (13) is formed as a door portion to be opened outwardly when applied with a thrust force caused by inflation of the air bag.

Description: The present invention relates to a vehicle seat equipped with a side air bag assembly mounted within one side of a back rest of the vehicle seat to ensure safety of a passenger from a great impact applied to a side portion of the vehicle body from the exterior in the occurrence of collision. In Japanese Patent Laid-open Publication No. 4(1992)-356246, (corresponding to the preamble of claim 1) there has been proposed a vehicle seat equipped with a side air bag assembly of this type which is composed of a casing housed within a side cavity formed in one side of a back rest of the vehicle seat and fixed to a back frame of the back rest, an inflator contained within the casing, an air bag assembled within the casing in a folded condition to be inflated by activation of the inflator and an air bag lid assembled with the casing to cover an opening of the side cavity. The air bag lid is hinged with an opening end of the casing at its base end to be opened outwardly when subjected to a thrust force caused by inflation of the air bag. In the conventional side air bag assembly, it is difficult to adjust a load acting on the air bag at the hinged portion of the air bag lid. In a condition where the side air bag assembly has been mounted within the one side of the back rest, the air bag lid is exposed to the exterior. This deteriorates the appearance of the vehicle seat. There is also a fear that the air bag lid is mischievously opened by hand. In the case that the air bag lid is covered with the seat cover of the back rest to avoid the foregoing problems, it is required to properly adjust a seamed portion of the seat cover where the air bag lid is opened outwardly to permit inflation of the air bag. However, the destruction strength of the seam portion is greatly influenced by the outer skin material of the seat cover and sewing thread. For this reason, the outer skin material of the seat cover is limited to an outer skin material such a vinyl chloride leather or a thin knitted cloth breakable at the seamed portion, and the sewing thread is also limited to a thread releasable at the seamed portion. In the case that a natural leather or a thick knitted cloth is used as the seat cover, it is required to increase the explosive force of the inflator. It is, therefore, a primary object of the present invention to provide a vehicle seat equipped with a side air bag assembly wherein the back rest of the vehicle can be designed in a desired form of high quality without any restriction to the material and design of the seat cover. According to the present invention, the object is accomplished by providing a vehicle seat equipped with a side air bag assembly the air bag of which is assembled within a side cavity formed in one side of a back rest of the vehicle seat in a folded condition, wherein a rear attachment board is mounted on a support frame of said back rest, characterized in that the rear attachment board has a back portion formed to cover the rear face of said back rest and a side portion formed to cover the air bag in said side cavity, wherein the side portion of said rear attachment board is formed as a door portion to be opened outwardly when subjected to a thrust force caused by inflation of said air bag. For a better understanding of the present invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Fig. 1 is a vehicle seat equipped with a side air bag assembly in accordance with the present invention; Fig- 2 is a sectional view taken along line 2-2 in Fig. 1; Fig. 3 is a sectional view illustrating an inflated condition of an air bag in the side air bag assembly shown in Fig. 2; Fig. 4 is a perspective view of a back frame assembly of a back rest of the vehicle seat shown in Fig. 1 and a casing to be mounted on one side of the back frame; Fig. 5 is a rear view of a rear attachment board assembled with the back rest of the vehicle seat shown in Fig. 1; Fig. 6(a) is a cross-sectional view taken along line 6-6 in Fig. 5; Fig. 6(b) is a cross-sectional view of a modification of the rear attachment board; Fig. 6(c) is a cross-sectional view of another modification of the rear attachment board; Fig. 7(a) is a vertical sectional view of the rear attachment board taken along line 7-7 in Fig. 5 in a folded condition of the air bag; Fig. 7(b) is a vertical sectional view of the rear attachment board taken along line 7-7 in Fig. 5 in an inflated condition of the air bag; Fig. 8(a) is a vertical sectional view of a first modification of the rear attachment board, corresponding with Fig. 7(a); Fig. 8(b) is a vertical sectional view of the first modification corresponding with Fig. 7(b); Fig. 9(a) is a vertical sectional view of a second modification of the rear attachment board, corresponding with Fig. 7(a); Fig. 9(b) is a vertical sectional view of the second modification of the rear attachment board, corresponding with Fig. 7(b); Fig. 10(a) is a vertical sectional view of a third modification of the rear attachment board, corresponding with Fig. 7(a); and Fig. 10(b) is a vertical sectional view of the third modification of the rear attachment board, corresponding with Fig. 7(b). Illustrated in Fig. 1 of the drawings is a vehicle seat equipped with a side air bag assembly 20 mounted within one side of a back rest 10a of the vehicle seat as shown in Fig. 2. The back rest 10a of the vehicle seat is in the form of a back rest cushion 11 supported by a back frame assembly 12 shown in Fig. 4. The back rest cushion 11 is composed of a cushion pad 11a covered with a seat cover 11b. As shown in Fig. 4, the back frame assembly 12 is composed of a U-letter shaped main frame 12a, a pair of vertically spaced lateral support members 12b fixed to the main frame 12a, a pair of vertical brackets 12c fixed to the opposite sides of the main frame 12a and a pair of support rods 12d fixed to the opposite sides of main frame 12a. As shown in Fig. 2, the seat cover 11b is provided at its opposite sides with a plurality of hooks 11c which are engaged with the support rods 12d of back frame assembly 12 to retain the cushion pad 11a on the back frame assembly 12. The side air bag assembly 20 is housed within a side cavity 14 formed by a rear attachment board 13 which is fixed to the lateral support members 12b of back frame assembly 12 and spaced in a predetermined distance from the rear face of back rest cushion 11. The rear attachment board 13 is in the form of a base plate 13a covered with an outer skin material 13b. The seat back board 13 has a back portion 13c formed to cover the rear face of back rest cushion 11 and a pair of laterally spaced side portions 13d formed to cover both the side faces of back rest cushion 11. The side cavity 14 has a vertical rectangular opening covered by the side portion 13d of rear attachment board 13. The air bag assembly 20 includes an inflator 21 housed within a casing 23 mounted on the vertical bracket 12c of back frame assembly 12 as shown in Fig. 4 and an air bag 22 connected with the inflator 22 and contained in the casing 23 in a folded condition. The inflator 21 is connected to a collision sensor (not shown) mounted on a side portion of the vehicle body such as a side door. When the occurrence of collision at the side portion of the vehicle body is detected by the collision sensor, the inflator 21 is activated by an electric signal applied from the collision sensor under control of an electric controller (not shown) to inflate the air bag 22 at a side portion of the back rest 10a as shown in Fig. 3. As shown in Figs. 1 and 5, one of the side portions 13d of the rear attachment board 13 is formed with a pair of vertically spaced lateral slits 13d1 which are extended to a position adjacent a corner between the back portion 13c and side portion 13d of the rear attachment board 13. The lateral slits 13d1 are formed in such a manner as to completely cut off the base plate 13a and outer skin material 13b of the rear attachment board 13. As shown in Fig 5(a), the seat back board 13 is further formed at its internal surface with a vertical groove 13e which is located at the corner of the back portion 13c and side portion 13d between the lateral slits 13d1. With the vertical groove 13e, the corner between the back portion 13c and side portion 13d of rear attachment board 13 is formed as a hinge portion, and the side portion 13d of rear attachment board 13 between the lateral slits 13d1 is formed as a door portion 13d2 to be opened outwardly when subjected to a thrust force from the interior. Assuming that the air bag 22 has been inflated by activation of the inflator 21 in the occurrence of collision at the side portion of the vehicle, the door portion 13d2 of rear attachment board 13 is opened outwardly by a thrust force applied thereto from the interior to permit the inflation of the air bag 22 as shown in Fig. 3. In this instance, the lateral slits 13d1 of rear attachment board 13 are expanded as shown in Fig. 7(b). Since in the vehicle seat, the side portion 13d of rear attachment board 13 between the lateral slits 13d1 is formed as the door portion 13d2 to permit inflation of the air bag 22, a load acting on the air bag 22 can be adjusted in a simple manner at the hinge portion of rear attachment board 13. Thus, the back rest 10a of the vehicle seat can be designed in a desired form without any restriction to the material and design of the seat cover 11b to provide a vehicle seat of high quality with a superior appearance. In addition, maintenance and inspection of the air bag assembly 20 can be carried out in a simple manner by removal of the rear attachment board 13 from the back frame assembly 12. Illustrated in Fig. 6(b) is a modification of the hinge portion of the rear attachment board 13, wherein the base plate 13a of attachment board 13 is formed with a plurality of parallel vertical grooves 13f between the lateral slits 13d1 so that a hinge portion is formed by the outer skin material 13b at the corner between the back portion 13c and side portion 13d of the rear attachment board 13. In Fig. 6(c) there is illustrated another modification of the hinge portion of the rear attachment board 13, wherein the base plate 13a of attachment board 13 is formed with a vertical slit 13g between the lateral slit 13d1 so that a hinge portion is formed by the outer skin material 13b at the corner between the back portion 13c and side portion 13d of the rear attachment board 13. In Fig. 8(a) there is illustrated a first modification of the lateral slits 13d1 of attachment board 13, wherein a backing plate 13h is adhered to an internal surface of the base plate 13a respectively at the lateral slits 13d1 while the outer skin material 13b is inwardly folded respectively at the lateral slits and adhered to the backing plate 13h to form a lateral groove 13d3. In this modification, the outer skin material 13b and backing plate 13h are cut off at the center of the lateral groove 13d3 to be separated as shown in Fig. 8(b) when subjected to a thrust force caused by inflation of the air bag 22. Illustrated in Fig. 9(a) is a second modification of the lateral slits 13d1 of attachment board 13, wherein the lateral slits 13d1 each are covered with the outer skin material 13b adhered to the base plate 13a to be removed therefrom as shown in fig. 9(b) when subjected to a thrust force from the interior. In Fig. 10(a) there is illustrated a third modification of the lateral slits 13d1 of attachment board 13. wherein a connecting plate 131 is adhered to the base plate 13a to cover the lateral slit 13d1. In this modification, the connecting plate 13i is formed with a lateral v-groove at the center of lateral slit 13d1 to be broken as shown in Fig. 10(b) when subjected to a thrust force from the interior.

Claims: A vehicle seat equipped with a side air bag assembly (20) the air bag (22) of which is assembled within a side cavity (14) formed in one side of a back rest (10a) of the vehicle seat in a folded condition, wherein a rear attachment board (13) ist mounted on a support frame (12) of said back rest, characterized in that the rear attachment board (13) has a back portion (13c) formed to cover the rear face of said back rest (10a) and a side portion (13d) formed to cover the air bag (22) in said side cavity (14), wherein the side portion (13d) of said rear attachment board is formed as a door portion (13d 2 ) to be opened outwardly when subjected to a thrust force caused by inflation of said air bag. A vehicle seat as claimed in Claim 1, wherein said rear attachment board (13) is formed with a hinge portion (13e) at a corner between said back portion (13c) and side portion (13d) thereof. A vehicle seat as claimed in Claim 1, wherein the side portion (13d) of said rear attachment board (13) is formed with a pair of vertically spaced lateral slits (13d 1 ) at a place opposed to an opening of the side cavity (14) in said back rest, a hinge portion (13e) is formed at a corner of the back portion (13c) and side portion (13d) of said rear attachment board (13) located between said lateral slits (13d 1 ), and the side portion (13d) of said rear attachment board located between said lateral slits (13d 1 ) is formed as said door portion (13d 2 ) to be opened outwardly when subjected to a thrust force caused by inflation of said air bag. A vehicle seat as claimed in Claim 2, wherein said rear attachment board 13 is composed of a base plate (13a) covered with on outer skin material (13b), and wherein the base plate (13a) of said attachment board is formed at its internal surface with a vertical groove (13e) at the corner between said back portion (13c) and side portion (13d) to provide said hinge portion. A vehicle seat as claimed in Claim 2, wherein said rear attachment board (13) is composed of a base plate (13a) covered with an outer skin material (13b), and wherein the base plate (13a) of said attachment board is formed at its internal surface with a plurality of vertical grooves (13f) at the corner between said back portion (13c) and side portion (13d) to provide said hinge portion. A vehicle seat as claimed in Claim 2, wherein said rear attachment board (13) is composed of a base plate (13a) covered with an outer skin material (13b), and wherein the base plate (13a) of said attachment board is formed with a vertical slit (13g) at the corner between said back portion (13c) and side portion (13d) to provide said hinge portion. A vehicle seat as claimed in Claim 3, wherein said rear attachment board (13) is composed of a base plate (13a) covered with an outer skin material (13b), and wherein said lateral slits (13d 1 ) are covered with the outer skin material (13b) of said base plate. A vehicle seat as claimed in Claim 3, wherein said rear attachment board (13) is composed of a base plate (13a) covered with an outer skin material (13b), and wherein a backing plate (13h) is adhered to an internal surface of said base plate (13a) respectively at said lateral slits (13d 1 ) while the outer skin material (13b) is inwardly folded respectively at said lateral slits and adhered to the backing plate (13h) to form a lateral groove (13d 3 ), said outer skin material (13b) and said backing plate (13h) being cut off at the center of the lateral groove (13d 3 )to be separated when subjected to a thrust force caused by inflation of said air bag (22).

Inventors: HASEGAWA YASUNORI, KATO HISAAKI, OHNO MITSUYOSHI, OYABU MASANORI, YANASE HITOSHI, HASEGAWA, YASUNORI, KATO, HISAAKI, OHNO, MITSUYOSHI, OYABU, MASANORI, YANASE, HITOSHI, Hasegawa, Yasunori, c/o Toyota Jidosha K.K., Kato, Hisaaki, c/o Toyota Jidosha K.K., Ohno, Mitsuyoshi, c/o Toyota Jidosha K.K., Oyabu, Masanori, c/o Toyota Jidosha K.K., Yanase, Hitoshi, c/o Araco K.K.
Applicants: ARACO KK, TOYOTA MOTOR CO LTD, ARACO KABUSHIKI KAISHA, TOYOTA JIDOSHA KABUSHIKI KAISHA
Application year: 1996
Main classification: B60R21
IPC codes: B60R21