GB2410009A

GB2410009A - An air-bag unit

Info

Publication number: GB2410009A
Application number: GB0401095A
Authority: GB
Inventors: Jean Francois Jambut; Thierry Jacqmarcq; Marianne Pobelle
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2004-01-19
Filing date: 2004-01-19
Publication date: 2005-07-20
Also published as: GB0401095D0

Abstract

An air-bag unit 1 comprises a housing 3 defining a chamber 4 to receive a folded air-bag 9. The interior of the chamber is shaped so that the shape of the interior of the chamber corresponds with the shape of the exterior of the folded air-bag. The folded air-bag is thus retained securely in position within the chamber. The housing is preferably provided with a hinged mounting panel 5 which can be hinged from an open position to a closed position to close the chamber and also trap part of a safety-belt so that the unit is mounted on the safety-belt.

Description

24 1 0009

DESCRIPTION OF INVENTION

"AN AIR-BAG UNIT" THE PRESENT INVENTION relates to an air-bag unit and more particularly relates to an air-bag unit for use with a "bag-in-belt" system.

It has been proposed previously to provide an air-bag which is to be mounted on the LAP part of a conventional lap-and-diagonal or three-point safety-belt.

If an air-bag is provided which is mounted on the lap part of a lap-anddiagonal safety-belt, the air-bag can be deployed to be in a precisely predetermined position relative to the seat occupant. This can be advantageous, since difficulties can arise if an air-bag is inflated at a position which is not precisely pre-determined with regard to the torso of the seat occupant. If an air- bag is mounted, for example, in a steering-wheel or dashboard, the seat occupant may be a relatively short person, having their seat adjusted to a forward-most position, or alternatively may be a tall person, having their seat adjusted to a rear-most position. In these two extreme cases the position of the torso relative to the position of the air-bag is very different. l

Various types of air-bag unit have been proposed before to be mounted on a safety-belt. The present invention seeks to provide an improved air-bag unit.

According to this invention there is provided an air-bag unit, the airbag unit comprising a housing defining an interior chamber, the chamber receiving a folded air-bag, the housing being provided with a mount to mount the housing on a safety-belt, the interior of the chamber being shaped such that the shape of the interior of the chamber corresponding with the shape of the exterior of the folded air-bag.

Preferably part of the housing defining the chamber is formed from a material which incorporates a thermo-compressive material, the thermo compressive material having been thermo-compressed to provide the 1 S appropriate shape.

Conveniently the thermo-compressive material is a foamed material.

Preferably the foamed material is a foamed polyurethane or foamed polyethylene.

Alternatively the housing is provided with an injected foamed instill, the injected foamed infll having a shape corresponding to the shape of the exterior of the folded air-bag.

Preferably the exterior of the housing is provided with an outer layer foamed from style fabric, leather, simulated leather or a soft plastics material.

Preferably the chamber is closed by a closure, the closure being secured in position.

Advantageously the closure is secured by snap-fastening, welding, stitching, gluing or by a zip fastener.

Conveniently the mount comprises a mounting panel connected to the housing.

Preferably the mounting panel is the closure and can be moved from an open position in which access is available to the interior of the chamber within the housing, and a closed position in which the chamber is closed.

Advantageously part of the housing defining the chamber is provided with a split-line.

Preferably the split-line is a line of mechanical weakness.

Alternatively the split-line is a seam.

In some embodiments the split-line is on the top of the unit directed away from the safety-belt when in use.

In other embodiments the split-line is on the side of the unit.

Conveniently the unit is provided with a pre-moulded end cap.

Alternatively an end part of the unit is sewn.

The invention also relates to a unit of the type described above when mounted on a safety-belt.

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 perspective view of an air-bag unit in accordance with the invention mounted on a safety-belt, FIGURE 2 is a view showing the unit of Figure 1 in an opened condition with the air-bag separated from the housing of the unit, FIGURE 3 is a sectional view showing the material from which part of the unit is fabricated, FIGURE 4 is a view corresponding to Figure 1 illustrating a split-line in the unit, FIGURE 5 is a drawing corresponding to Figure 1 showing another split-line in the unit, FIGURE 6 is a drawing corresponding to Figure 1 showing yet another split-line in the unit, and FIGURE 7 is a view of an end cap which may be utilised with the unit.

Referring initially to Figure 1, an air-bag unit 1 is provided which is to be mounted on a belt or strap 2 which may conveniently form a lap-anddiagonal seat-belt arrangement. The unit may be mounted on the lap part of such a safety-belt arrangement.

The air-bag unit 1 comprises an upper or housing part 3, the upper or housing part 3 defining an interior chamber 4. In the illustrated embodiment, a mounting panel 5 is provided which is hingedly connected to one side of the housing part 3 that defines the chamber 4. The mounting panel 5 is hingedly mounted in position about a hinge-line 6 and may move, in the direction generally indicated by the arrow 7, from an open position, as shown in Figure 2, in which there is ready access to the chamber 4, to a closed position in which the panel effectively closes the under-surface of the chamber 4. The panel may be secured in position by means of a snap-fastening, welding, stitching, gluing or even a zip fastener. The safety-belt 2 may be trapped between the panel 5 and the under-part of the housing 3 that defines the chamber 4, enabling the unit to be mounted in position on a safety-belt 2 as shown in Figure 1. In a modified embodiment the chamber itself is provided with a closure which is secured in position to close the chamber, before the panel 5 is moved to trap the belt against the chamber 4.

The chamber 4 is provided, at one end, with an access passage 8 which leads to the exterior of the housing.

The chamber 4 receives a package 9, which constitutes a folded air-bag.

The folded air-bag 9 is provided with an umbilical 10 which extends through the passage 8. The umbilical may contain an electric cable to supply a signal to a gas generator present within the folded air-bag 9. Alternatively the umbilical 10 may be a gas duct extending from a remote gas generator.

The air-bag 9 is folded so that the lower surface of the folded air-bag, that is to say the surface visible in Figure 2, which is to lie immediately adjacent the safety-belt 2 is substantially flat. However, the upper surface of the air-bag, which is the surface which will be in contact with that part of the housing 3 which defines the chamber 4, will most probably be of an irregular form, due to the nature of the folding process.

To ensure that the folded air-bag is retained appropriately within the chamber 4, whilst the exterior of the chamber has a pleasing smooth or flush appearance, the interior surface of the chamber 4 is shaped to have a shape corresponding to or congruent with the shape of the exterior of the folded air bag 9. The shaping of the interior of the housing may be achieved in a number of ways.

Figure 3 illustrates, in cross-section, a preferred material utilised to fabricate that part of the housing 3 which defines the chamber 4. The material 20 comprises three layers. An inner layer 21 is provided which is formed of a material selected for its desired mechanical properties. The material may therefore be a muslin net or scrim-like material.

The next adjacent layer, layer 22, in the preferred embodiment is a foamed material formed of polyurethane or polyethylene, for example. The foam layer may be provided with an appropriate shape as will be described below.

The upper-most layer, which will form the exterior of the unit, is layer 23 which may be formed of a style fabric, a leather or simulated leather, or a "soft" plastics material such as an appropriate polyvinyl chloride. The upper layer provides an appropriate look and feel to the unit, so that the unit is acceptable within the environment of the cabin of a motor vehicle.

As mentioned above, the foam layer 22 may be shaped. The foam layer may be shaped using a thermo-compression technique. It is possible to utilise a hot mould with a cold material of the type shown in Figure 3, the mould being lO utilised to thermo-compress the foam layer 22 so that the interior of the chamber 4 possesses the appropriate shape. Alternatively a cold mould may be utilised with material 20 whilst the material 20 is hot.

In an alternative embodiment of the invention, instead of using a material of the type shown in Figure 3, the housing 3 may be made of a substantially rigid material. The chamber 4 within the housing will be dimensioned so that when the folded air-bag 9 has been located within the chamber, a space exists between the air-bag 9 and the chamber. A foamed plastics material may then be injected into the space between the folded air-bag and the interior of the housing 3, the foam automatically adopting an appropriate shape, corresponding to the shape of the exterior of the folded air- bag. In this situation the interior of the chamber 4 is still shaped with a shape corresponding to the shape of the exterior of the folded air-bag.

The upper-most part of the housing 3 may be provided with an appropriate split-line, the split-line being a line of mechanical weakness intended to rupture when the air-bag is inflated, or a seam. The split-line may, as shown in Figure 4, have the form of an open "U", the split-line being line 30.

In an alternative embodiment, as shown in Figure 5, the split-line 31 may have the form of a "I" or very broad "H". Alternatively again the splitline may be on the side of the housing facing the lap of the occupant, as shown by split one 32 in Figure 5.

If desired the unit 1 may be provided with a moulded end cap 32, as shown in Figure 7 to be mounted on the end of the unit when it is in position on the seat-belt. The end cap will ensure that the unit is appropriately located and has an appropriately pleasing appearance. Alternatively, the end part of the housing may be sewn, as shown by stitching 33 in Figure 5.

It is to be understood that the air-bag unit, when mounted on the air-bag has substantial integrity, in that prying fingers cannot obtain access to the interior of the unit. The unit has a pleasing appearance and has an appropriate exterior feel. The folded air-bag is retained firmly within the unit due to the congruence of the shape of the exterior of the folded air-bag and the shape of the interior of the cavity or chamber within the housing, so that the air-bag itself is held firmly in position within the housing, without the air-bag moving relative to the interior of the housing. The air-bag itself may be packaged within the chamber in such a way that the unit may subsequently be mounted on a safety-belt.

When used in this Specification and Claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

Claims

CLAIMS: 1. An air-bag unit, the air-bag unit comprising a housing defining

an interior chamber, the chamber receiving a folded air-bag, the housing being provided with a mount to mount the housing on a safety-belt, the interior of the chamber being shaped such that the shape of the interior of the chamber corresponding with the shape of the exterior of the folded air-bag.
2. A unit according to Claim 1 wherein part of the housing defining the chamber is formed from a material which incorporates a thermo-compressive material, the thermo-compressive material having been thermo-compressed to provide the appropriate shape.
3. A unit according to Claim 2 wherein the thermo-compressive material is a foamed material.
4. A unit according to Claim 3 wherein the foamed material is a foamed polyurethane or foamed polyethylene.
5. A unit according to Claim 1 wherein the housing is provided with an injected foamed infill, the injected foamed infill having a shape corresponding to the shape of the exterior of the folded air-bag.
6. A unit according to any one of the preceding Claims wherein the exterior of the housing is provided with an outer layer formed from style fabric, leather, simulated leather or a soft plastics material.
7. A unit according to Claim 1 wherein the chamber is closed by a closure, the closure being secured in position.
8. A unit according to Claim 8 wherein the closure is secured by snapfastening, welding, stitching, gluing or by a zip fastener.
9. A unit according to any one of the preceding Claims wherein the mount comprises a mounting panel connected to the housing.
10. A unit according to Claim 9 as dependent on Claim 7 and Claim 8 wherein the mounting panel is the closure and can be moved from an open position in which access is available to the interior of the chamber within the housing, and a closed position in which the chamber is closed.
11. A unit according to any one of the preceding Claims wherein part of the housing deeming the chamber is provided with a split-line.
12. A unit according to Claim 11 wherein the split-line is a line of mechanical weakness.
13. A unit according to Claim 11 wherein the split-line is a seam.
14. A unit according to any one of Claims 11 to 13 wherein the split-line is on the top of the unit directed away from the safety-belt when in use.
15. A unit according to any one of Claims 1 1 to 13 wherein the splitline is on the side of the unit.
16. A unit according to any one of the preceding Claims wherein the unit is provided with a pre-moulded end cap.
17. A unit according to any one of Claims 1 to 16 wherein an end part of the unit is sewn.
18. An air-bag unit substantially as herein described with reference to and as shown in the accompanying drawings.

l 9. Any novel feature or combination of features disclosed herein.