GB2262919A

GB2262919A - Vehicle air bag.

Info

Publication number: GB2262919A
Application number: GB9226595A
Authority: GB
Inventors: Akira Kokeguchi; Hideo Nakajima
Original assignee: Takata Corp
Current assignee: Takata Corp
Priority date: 1992-01-06
Filing date: 1992-12-21
Publication date: 1993-07-07
Anticipated expiration: 2012-12-21
Also published as: CA2085702A1; GB9226595D0; JPH05186961A; KR930016284A; DE4300125C2; DE4300125A1; FR2685894A1; GB2262919B; FR2685894B1

Description

1 A; 2262919

TITLE OF THE INVENTION

Structure for Stitching a Tether Belt of an Air Bag FIELD OF THE INVENTION

The present invention concerns a structure for stitching a tether belt of an air bag in an air bag device mounted on a vehicle. More in particular, it relates to a structure for stitching a tether belt of an air bag capable of firmly stitching the tether belt to the bag.

DESCRIPTION OF THE PRIOR ART

As is well-known, an air bag device is adapted to extend an air bag upon collision of a vehicle or the like thereby protecting an occupant.

In the air bag device, a tether belt is stitched to the bag so that the air bag is extended into a predetermined shaje.

Fig. 2 is a perspective view illustrating the extended shape of an air bag in an air bag device for use in a passenger seat. An air bag 10 is attached at a flanged portion 14 of an opening 12 to a container tot illustrated) by means of bolts or rivets. Then, when a gas from en inflator (not illustrated) is introduced passing through the opening 12 to the inside of the air bag 10, the air 1 bag extends as shown in the drawing. 18 denotes a vent hole.

For keeping the central portion on the front side of the air bag 10 from protruding toward an occupant, the central portion on the front side and a vicinity of the opening 12 of the air bag 10 are connected by a tether belt 20.

Fig. 3 shows a stitching structure between a cloth substrate (base cloth) 22 of the air bag 10 and the tether belt 20 in the prior art. As shown in Fig. 3, a seam 30 is generally in the shape of a numerical figure of "eight" comprising-first and second seams 31, 32 perpendicular to the longitudinal direction of the tether belt 20 and third and fourth seams 33 and 34 oblique to the longitudinal direction. The third and fourth seams 33 and 34 connect the ends of the first and the second seams 31 and 32 to each other. As shown in the drawing, the first and the second sedns 31 and 32 are stitched only the central portion while leaving the lateral ends of the tether belt unstitched.

When the air bag extends, a large tension is applied to the tether belt 20 in the longitudinal direction. In a case where the seam 30 is present only in the central portion of the tether belt 20 as shown in Fig. 3, all the tension including that at the lateral ends of tether belt 2 1 11 are concentrated to the vicinity of the ends of the first and the second seams 31 and 32. In particular, if the tether belt 20 is in an oblique state as shown by dashes and dotted lines in Fig. 3, an extremely large force is exerted near the end A of the seam 31. In view of the above, it has been necessary to firmly set the seams 31 and 32, which makes the stitching of the tether belt 20 laborious.

OBJECT AND SUMMARY OF THE INVENTION

An object of the present invention is to provide a simple and convenient structure capable of firmly connecting a tether belt and air bag.

In accordance with the first aspect of the present invention, in a structure for stitching a tether belt of an air bag in which a tether belt is disposed at the inside of a bag main body of an air bag and an end of the tether belt is stitched to.the bag main body, a seam of the stitclYed portion laterally traverses the tether belt.

In accordance with the second aspect of the present invention, in a structure for stitching a tether belt of an air bag as defined in the first aspect, the seam is generally in the shape of a numeral figure of "eighC comprising a first stitch and a second stitch laterally traversing the tether belt, and third and fourth seams that connect ends of the first and the second seams to 3 each other and obliquely traverse to the tether belt.

According to the structure for stitching a tether belt of an air bag in the present invention, since the seams completely traverse the tether belt, a large stress is prevented from exerting locally on the tether belt even if a tensile stress is applied to the tether belt. Therefore, the stitching strength required for the seams can be reduced to facilitate stitching. In particular, in the second aspect, each of the first through fourth seams completely transverses the tether belt and the tether belt can be retained firmly to a cloth substrate of the bag main body.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a plan view illustrating a structure for stitching a tether belt of an air bag in a preferred embodiment according to the present invention; Fig.--;2 is a perspective view of an air bag for-use in a passenger seat in an extended state; and Fig. 3 is a plan view illustrated a structure for stitching a tether belt of a air bag in the prior art.

PREFERRED EMBODIMENT Fig. 1 is a plan view for a stitched portion illustrating a structure for stitching a tether belt of an air 4 CL is bag in a preferred embodiment according to the present invention. A tether belt 20A is stitched to a cloth substrate (base cloth) 22A of a bag main body by means of a seam 40 which is generally of a shape of a numerical figure of "eight" comprising first, second, third and fourth seams 41, 42, 43 and 44. The first and the second seams 41 and 42 laterally. traverse the tether belt 20 and both ends of the seams are present beyond the tether belt 20A.. The third and the fourth seams 43 and 44 obliquely traverse the tether belt 20A and both ends of the seams are present beyond the tether belt 20A. The third and the fourth seams 43 and 44 connect the ends of the first and the second seams 41 and 42 to each other.

In this way, in the structure for stitching the tether belt of the air bag according to this embodiment, since the seam 40 completely traverses the tether belt, if a tensile stress is applied to the tether belt 20A, a large stress can be prdvented from exerting locally on the tether-belt 20A. Accordingly, the stitching strength required for the seam 40 can be reduced to facilitate stitching. In particular, in this embodiment, each of thefirst through fourth seams 41 - 44 completely traverses the tether belt 20A and the tether belt 20A can firmly be secured to the cloth substrate 22A.

This embodiment concerns an air bag for use in the - 5 passenger seat but the present invention is also applicable to an air bag for use in a driver seat.

As has been described above, in the structure for stitching the tether belt of the air bag in accordance with the present invention, since the seam completely traverses the tether belt, a large stress can be pre vented from exerting locally on the tether belt and the stitching strength required for the seam can be reduced to facilitate stitching.

6 1

Claims

WHAT IS CLAIMED IS

1. A structure for stitching a tether belt of an air bag in which a tether belt is disposed at the inside of the air bag and the end of the tether belt is stitched to said air bag, wherein a seam of a stitched portion laterally traverses the tether belt.

2. A structure for stitching a tether belt of an air bag as defined in claim 1, wherein the seam is generally in the shape of a numerical figure of "eight" comprising a first seam and a second seam laterally traversing the tether belt, as well as a third seam and a fourth seam for connecting the ends of the first seam and the second seam to each other and obliquely traversing the tether belt.

3. A structure as defined in claim 2, wherein each of the firstz-through fourth seams is present also in the portion on the lateral sides of the tether belt.

4. A structure for stitching a tether belt of an air bag substantially as hereinbefore described with reference to Figure 1 of the drawings.