It has been proposed to provide air-bags located at many positions within motor vehicles, with the air-bags being adapted to be inflated in the event that an accident should occur to provide protection for an occupant of the vehicle.

It has been proposed to make air-bags from various fabrics and materials. A woven fabric has been widely used, but it has been found that when a tear appears in the fabric, it is commonplace for the tear to increase in size rapidly due to the fact that the fabric is woven, and, at any one instant, the load appearing between the two opposed edges of the tear is applied to only one or two fibres. Thus the fibres break sequentially enabling the tear to grow rapidly.

It has been proposed to provide an air-bag formed from a plastics material film and a reinforcing member arranged in connection with the film for arresting the propagation of a tear in the film. US-A-5746446 shows an arrangement of this type, but the member associated with the plastics material film is a net. Thus this arrangement also suffers from the problem of a tear

being prone to extend in length due to the sequential breaking of parts of the net.

According to one aspect of this invention, there is provided an air-bag, the air-bag being formed from a layer of material, the layer being reinforced by randomly orientated fibres.

Preferably, the fibres are extruded.

Conveniently, the fibres are relatively long having average length in excess of 25mm.

Preferably, the fibres are adhered to the plastics film.

Alternatively, the fibres are embedded in the plastics film.

Conveniently, at least one area of the material forming the air-bag has a larger proportion of fibres than another area of the material forming the air-bag.

Preferably, at least one area of the material forming the air-bag have different properties to the properties of the fibres in the rest of the material.

Conveniently, said layer is a plastics material film.

According to another aspect of this invention there is provided a material for use in forming an air-bag the material comprising a plastics film to which is adhered a plurality of fibres in a random orientation.

Preferably the fibres are extruded fibres.

Conveniently the fibres have a average length in excess of 25mm.

According to the further aspect of this invention there is provided a method of manufacturing a material for use in making an air-bag, the method comprising the steps of taking a layer of material, applying adhesive to one side of the layer, and bonding a plurality of fibres in a random orientation to the adhesive.

In one embodiment of the invention the fibres are applied to the adhesive by a spreading machine which spreads the fibres across an adhesive coated side of the plastics material.

In an alternative embodiment of the invention the fibres are air-blown on to the adhesive.

In a further embodiment of the invention the fibres are initially located on a first surface and the adhesive coated film is lowered on to the fibres, with the adhesive coating coming into contact with the fibres.

Preferably, the layer of material is a film of plastics 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 view illustrating the tearing of a fabric or net,

FIGURE 2 is a plan view of part of a material in accordance with the invention, FIGURE 3 is a cross-sectional view of part of the material of Figure 2 and FIGURE 4 is a view of an air-bag made from the material of Figures 2 and 3.

Referring initially to Figure 1 of the accompanying drawings a woven or net-like material 1 is shown consisting of generally parallel yams or fibres 2 constituting a"weft"and also generally parallel yams or fibres 3 constituting a "warp". A"tear"has commenced as shown as the tear 4. It can be seen that the tear separates two distinct areas 5,6 of the woven material, and if these areas tend to move further apart a substantial force is applied to the particular yarn or fibre 7 appearing at the base or apex of the tear. That particular yarn or fibre 7 may thus readily break, increasing the size of the tear 4 and then applying a similar pressure or force to the next adjacent weft yarn or fibre 8.

Thus the tear can rapidly grow in size.

Figures 2 and 3 illustrate a material in accordance with the invention.

The material of Figures 2 and 3 comprises a thin layer of material which in this embodiment is a plastics film 10. One surface of the film 10 is provided with an adhesive layer 11 which adheres randomly orientated fibres to the film 10.

The plastics material film may initially be spread out flat on a bed or table. A layer of adhesive 11 may be applied to the top of the film and long fibres, such as extruded fibres 12, may be randomly spread out on the adhesive

layer 11. The fibres may be spread using a fibre spreading machine which may deposit fibres on the adhesive film 11 and, by means of a knife or blade having its lower edge spaced immediately above the adhesive film 11, may move the fibres across the top of the adhesive film until the fibres are spread evenly across and adhered to the adhesive film. Finally, the plastics film 10, the adhesive 11 and fibres 12 on top of the adhesive may be passed through an appropriate roller unit to ensure that the fibres 12 are firmly bonded, by the adhesive layer 11, to the film 10. As can be seem in Figure 2 the fibres adopt a random orientation or pattern. Figure 2 shows part of the film surrounding a hole or aperture 13.

The fibres used in performing the invention are preferably extruded fibres and may thus be fibres of a polyamide material or some other polymer material. However, other fibres may be utilised. Fibres may be long or short but it is preferred to use long fibres, as long fibres provide enhanced strength.

It is preferred for the average length of the fibres to exceed 25mm.

While one method of applying the fibres to the adhesive coated layer or film has been described, the fibres may be applied to the adhesive using many alternative techniques. For example, fibres may be air-blown on to the adhesive layer. Alternatively the fibres may be spread out upon a table or other surface, and then the plastics material film, with one side thereof coated with adhesive, may be lowered on to the table, with the adhesive coating coming into contact with the fibres. A roller or other mechanism may be used to press the plastics film 10 downwardly so that the adhesive 11 becomes firmly bonded to the fibres 12.

Figure 3 illustrates an air-bag 20 made from a material as described above. The air-bag 20 is mounted in a steering wheel 21 of a motor vehicle to

provide protection for an occupant 22 of the vehicle. The air-bag is shown as it inflates. It may be desirable for a specific area of the material forming the air- bag, such as the area 23 which is the area of the air-bag which, when fully inflated, will be impacted by the occupant of the vehicle 22, to be somewhat stiffer than other areas of the air-bag. Thus the material used in the manufacture of the air-bag 20 may be such that the number of fibres present in the material will be increased or enhanced in the area 23 as opposed to the remaining areas of the material, thus enhancing the stiffness of this area. The air-bag has a vent hole 24. The area 25 of the material around the vent hole may have fibres with different properties as compared with the fibres in other parts of the material forming the air-bag. The fibres may be stronger, for example by being of greater diameter, to withstand the high load generated adjacent the vent hole.

Whilst the invention has been described with reference to embodiments in which fibres are adhered to a plastics film, it is to be appreciated that a material in accordance with the invention may be fabricated using other techniques. For example, fibres may be incorporated into a hot-melt of polymer, with that hot-melt of polymer subsequently being processed to produce a film of plastics, that film of plastics having the elongate fibres incorporated therein.

In the present Specification"comprise"means"includes or consists of' and"comprising"means"including or consisting of".