GB2328185A

GB2328185A - Seat belt airbag

Info

Publication number: GB2328185A
Application number: GB9717258A
Authority: GB
Inventors: Simon Valkenburg; Jan Valkenburg; David Stow; Andreas Bissinger; Gerhard Koch
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 1997-08-14
Filing date: 1997-08-14
Publication date: 1999-02-17
Anticipated expiration: 2017-08-14
Also published as: GB2328185B; GB9717258D0

Abstract

A safety device comprises an elongate seat belt 1 comprising two superimposed layers 2, 3 which are connected together in some areas 4 but not in others 5, so as to form a pocket 6 within the belt, said pocket receiving an airbag 13 and being formed with an opening 8 closed by breakable or yieldable means. The pocket may be formed between a seam 7 on one edge of the belt and the breakable or yieldable means adjacent the other edge. The belt may be formed by a one piece weaving technique, the seams at the edges of the belt being formed by threads from one layer being interwoven with the other layer, one of which may be a weak seam, eg by using weak threads to interconnect the layers. A passage 10 may be provided within the belt from the pocket to an end of the belt, said passage may carry a pipe for inflating gas for the airbag. The part of the belt around the airbag may have an appearance, eg words or colour, to indicate the presence of the airbag.

Description

IMPROVEMENTS IN OR RELATING TO A SEAT BELT THIS INVENTION RELATES to a seat belt, and more particularly relates to a seat belt intended for use in a motor vehicle.

It has been proposed to provide a seat belt with an airbag mounted in or on the lap part of the seat belt, the airbag being adapted to be inflated in the event that an accident should arise to provide protection for the occupant of the seat. US-A-3430979 shows a seat belt of this type adapted to provide protection for a front seat passenger, but a seat belt of this type may be of particular benefit for a rear seat passenger, where it is difficult to find a place to store an uninflated airbag that may be inflated to be in an appropriate position in the event that an accident should arise.

The invention seeks to provide an improved seat belt.

According to this invention there is provided a seat belt as defined in the accompanying claims In order that the invention may be more readily understood and so that further features thereof may be appreciated the invention will now be described by way of example with reference to the accompanying drawings in which FIGURE 1 is a side view of a seat belt with an airbag in accordance with the invention, with the airbag inflated following detection of an accident, FIGURE 2 is a plan view of part of the belt shown in Figure 1, FIGURE 3 is a section taken on line III-III of Figure 2, FIGURE 4 is a section taken on line IV-IV of Figure 2, FIGURE 5 is a section taken on line V-V of Figure 2, FIGURE 6 is a view corresponding to Figure 2, but illustrating a modified embodiment of the invention, and FIGURE 7 is a view of part a further modified embodiment of the invention.

Refening to Figures 1 to 5 a seat belt 1 in accordance with the invention may be used with a seat belt for a front seat of a motor vehicle, but is preferably used with a rear seat. The seat belt is made of two superimposed layers of fabric 2,3, and is formed as a one-step operation using a one-piece weaving technique. In using this technique two layers of fabric are woven simultaneously on a single loom, and in selected areas of the fabric threads from one of the layers of fabric are interwoven with threads from the other of the layers of fabric to form a region forming, for example, a seam.

In the embodiment show, in a first area 4 the upper and lower of the superimposed layers of fabric are interconnected by weaving threads from each of the layers with the treads of the other of the layers. In a second area 5 the layers are not interconnected. A rectangular pocket 6 is defined between the two separate layers of the area 5. The pocket is bounded, adjacent one longitudinal side edge of the belt, by a seam 7, which is formed by a strong interconnection between the upper and lower layers of fabric. The pocket is bounded, adjacent the other longitudinal side edge of the belt by a yieldable or breakable seam 8. The seam 8 is so located that the parts of the fabric adjacent the seam form an opening that is initially closed by means of the seam. The seam 8 is thus relatively weak. The seam 8 may be made from just a few threads from one of the layers of fabric being interwoven with the threads of the other layer, or with threads that have only a very few interweavings with threads of the other layer of fabric, although the fabric may include specially selected weak threads which are proved to be interwoven with the threads of the other fabric layer in the region of the seam 8 to form a seam that will readily break.

Thus the pocket 6 forms a chamber 9 within the part of the seat belt that is adapted to lie on the lap of an occupant of the seat when the seat belt is in use. The chamber 9 is connected, by means of a narrow conduit 10 that extends axially of the belt, again formed by part of the second area 5 where the layers of fabric are not interconnected, to a chamber 11 located at one end of the belt. The chamber 11 is formed by another part of the second area 5.

The chamber 11 is adapted to receive part of a gas generator 12 which is adapted to be connected to an anchor point 13 to anchor that end of the seat belt 1 firmly in position. The gas generator is connected, by means of a pipe, to an airbag which is initially in a folded and uninflated state within the pocket 6.

The gas generator is controlled by a sensor which responds to an accident being senses, for example by the detection of a substantial deceleration, to inflate the airbag As the gas from the gas generator flows along to the pipe to inflate the airbag the relatively weak seam 8 yields or breaks, thus establishing an opening in the pocket. The airbag emerges from the pocket through the opening to be located, as shown at 13 in figure 1 , in front of the person using the seat belt.

The seam 8 is directed away from the torso of the occupant, and thus there is part of the seat belt between the torso of the occupant and the bag. The bag is located in an appropriate position to protect the occupant.

The end of the seat belt provided with the pocket and the gas generator is adapted to extend over the lap of the occupant. The other end of the seat belt, in the region 14 of Figure 2 is intended to be wound on a retractor. So that this part of the belt has an appropriate characteristic, the facilitate reeling, this part of the belt may be made with a substantial amount of interweaving the threads of the two layers so that the belt presents, in this region, the features of a belt comprising a single thick layer of fabric.

In the region of the pocket 6 the nature of the fabric layers may be modified. One or both of the layers may be formed from threads that have a reduced tension or which are relatively slack, so that the fabric is yieldable or has 'give'. This will facilitate the insertion of the airbag in the chamber 9. The upper layer of fabric may have a different appearance in this region, by being a different colour, or even by having readable words woven into the fabric in threads of different colours, to act as a warning to the occupant that this part of the belt must be correctly positioned.

In the embodiment of Figures 1 - 5 the pocket 6 may initially be made to be open, with no seam 8 being present initially, with the seam being created by stitching after the airbag has been inserted into the pocket.

Figure 6 illustrates an alternative form of the invention in which the pocket extends from the position in the part of the belt which is to lie on the lap of the occupant of the seat to the end of the belt that is to be anchored in position. This arrangement facilitates the insertion of the airbag into the pocket.

The part of the pocket that is to receive the airbag is bounded by a strong seam 7 and a weak stream 8, but the parts of the pocket that do not receive the airbag are bounded by strong seams 15,16. The seam 15 is actually a continuation of the seam 7, while the seam 16 is a continuation, with enhanced strength, of the seam 8.

Figure 7 illustrates a modified embodiment in which at the two opposed ends of the belt there are areas 20, 21, where the two fabric layers are interconnected, and in a central region there is a tubular chamber 21 in an area where the fabric layers are not interconnected. A longitudinally extending slit 22 is provided giving access to the chamber 21. The fabric is woven so that relatively strong thread extend axially of the belt, and these threads absorbs any load applied to the seat belt should an accident occur. The transverse thread are relatively weak, and the cutting of the threads to form the slit does not significantly weaken the belt.

An airbag is located in the pocket, and a pipe 23 leads from a gas generator 24, through the slit into the airbag in the pocket. One end of the belt is provided with an anchor plate 25 which is to be connected to an anchor point. The gas generator may be located near the anchor point. The pocket may be provided with a region constituted by a weak seam of the type described above adapted to break to create an opening on inflation of the airbag.

Alternatively, the threads used which extend transversely of the belt in the region of the slit 22 may be selected to be weak so that as the air bag inflates the weak threads break and the slit becomes elongated, thus creating an opening through which the inflating airbag may emerge.

Claims

1. A seat belt, said seat belt comprising an elongate element comprising two superimposed layers, the seat belt having a first predetermined are in which the two layers are connected together, and having a second area where the two layers are not connected together, the second area defining a pocket to receive an air bag, the pocket having means adapted to form an opening therein, which is initially closed by yieldable or breakable means.

2. A seat belt according to claim 1 wherein one side of the pocket is defined adjacent one edge of the seat belt by seam means which securely interconnect the two superimposed layers, and the other side of the pocket is defined adjacent the opposite edge of the seat belt by said yieldable or breakable means.

3. A seat belt according to claim 1 wherein the pocket is provided with an initial opening in the form of a slit.

4. A seat belt according to claim 1 wherein the seat belt is formed using a onepiece weaving technique.

5 A seat belt according to claim 2 wherein the seam means adjacent the one edge of the belt comprises a seam where threads from one of the layers of fabric are interwoven with the threads from the other layer of fabric to form a strong seam.

6.A seat belt according to claim 3 wherein the seam means adjacent the other edge of the belt comprises a seam where threads from one layer of fabric are interwoven with threads from the other layer of fabric to form a weak seam.

7. A seat belt according to claim 6 wherein the said seam adjacent the other edge of the belt is formed using threads that are weaker than the remaining threads forming the fabric layers.

8. A seat belt according to any one of the preceding claims wherein, in said first area, the two layers of fabric are interconnected by threads from one of the layers of fabric which are interwoven with threads from the other of the layers of fabric.

9. A seat belt according to any one of the preceding claims wherein the pocket is connected to the end of the seat belt by a communicating passage that extend substantially axially of the belt to the said end of the belt.

10. A seat belt according to any one of claims 1 to 6 wherein the pocket is formed so that the pocket communicates with one end of the seat belt.

11. A seat belt according to claim 10 wherein said yieldable or breakable means extend over part of the length of the pocket, and stronger seam means extend over the rest of the length of the pocket.

12. A seat belt according to any one of claims 9 to 11 wherein the other end of the seat belt comprises a single layer of fabric woven from the threads that form said two layers.

13. A seat belt according to any one of the preceding claims wherein at least one of the layers of fabric is modified, as compared with the rest of the layers of fabric, in the region of said pocket.

14. A seat belt according to claim 13 wherein in the region of the pocket at least one of the layers of fabric is woven with threads of a different tension to make the fabric more yieldable.

15.A seat belt according to claim 13 wherein in region of the pocket one of the layers of fabric is woven to have a different appearance.

16. A seat belt according to any one of the preceding claims wherein the pocket contains an airbag, the airbag having a gas generator adapted to inflate the airbag in response to a detected accident.

17. A seat belt according to any one of the preceding claims wherein the gas generator is provided at an anchor point for the belt.

18. A seat belt according to any one of the preceding claims mounted in a motor vehicle so that, in use, when an airbag in the pocket inflates an emerges through the initially closed opening the airbag is directed away from the occupant of the seat wearing the seat belt, with part of the seat belt being located between the occupant and the bag.

19. A seat belt substantially as herein described with reference to and as shown in the accompanying drawings.

20. Any novel feature or combination of features disclosed hertein.