GB2299306A

GB2299306A - Inflatable airbag for a vehicle

Info

Publication number: GB2299306A
Application number: GB9506129A
Authority: GB
Inventors: Anthony Bruce Pike
Original assignee: AIRBAG PROTECTION SYSTEMS Ltd
Current assignee: AIRBAG PROTECTION SYSTEMS Ltd
Priority date: 1995-03-25
Filing date: 1995-03-25
Publication date: 1996-10-02
Also published as: GB9506129D0

Abstract

An inflatable airbag for incorporating in the headrest (1a) of a seat (1) in a vehicle and actuable in the event of crash, the airbag having a first portion (5) with a connecting portion (4) for connection to a source of pressurised gas (2) releasable into the airbag upon crash. A second portion (7), remote from the connecting portion (4), is arranged to face, and receive the impact of, a vehicle passenger upon crash in the seat behind. The first portion (5) comprises a plurality of flexible, inflatable tubes (6) each extending from the connecting portion (4) to the second portion (7), which presents a substantially continuous face (7A), when inflated, to receive a passenger impact. The skeletal form of the airbag reduces air pressure problems upon inflation in the confined space of a vehicle.

Description

INFLATABLE AIRBAG FOR A VEHICLE This invention relates to an inflatable airbag for use in a vehicle and actuable in the event of crash.

Known airbags in cars are connected to a source of pressurised gas which is released into the airbag upon vehicle crash, in order to receive the impact of and protect a vehicle passenger (including driver) in the crash.

Such airbags are rapidly inflated to a comparatively large volume of around 50 litres. This can cause problems in vehicle passenger compartments because of the increased pressure thereby produced.

According to the present invention, there is provided an inflatable airbag for use in a vehicle and actuable in the event of crash, the airbag having a first portion with a connecting portion for connection to a source of pressurised gas releasable into the airbag upon crash, and a second portion, remote from said connecting portion, arranged to face, and receive the impact of, a vehicle passenger upon crash; said first portion comprising a plurality of flexible, inflatable tubes each extending from said connecting portion to said second portion and said second portion presenting a substantially continuous face, when inflated, to receive a passenger impact.

The invention also extends to a vehicle incorporating an inflatable airbag essentially as just defined.

Preferably, the inflatable tubes are separate from one another along at least the majority of their length. In such a case, one or more tube constraints can be provided to control the angle of direction of extent of the tubes upon inflation.

Preferably, one set of ends of the tubes of the first portion connect into the connecting portion through a manifold arrangement.

Preferably ends of the tubes of the first portion remote from the connecting portion connect into the second portion of the airbag through a manifold arrangement.

It will be appreciated from the above that the airbag proper is constituted by the second portion of the airbag.

The correct angle of orientation of the second portion upon inflation can be obtained by varying the lengths of the tubes of the first portion.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which the single Figure is a diagrammatic side view of a vehicle passenger seat incorporating an inflatable airbag arranged to protect a vehicle passenger in a seat behind the one shown.

The drawing shows a vehicle passenger seat 1, which can be the front seat of a car, or one of any of the seats in a coach or an aircraft except the rear seats.

Installed in a head rest 1A is inflatable airbag equipment actuable in the event of a crash to protect a passenger in the seat behind (not shown).

The drawing actually shows the airbag arrangement after inflation. It would otherwise be stowed ready for use in the head rest 1A.

The head rest 1A incorporates a pressurised gas cylinder and control valve 2 to supply upon activation an airbag 3 through a gas distribution valve and manifold 4.

The connecting portion joins a first portion 5 of the airbag which comprises a plurality of inflatable tubes 6 each joined at one end through the manifold to the gas distribution valve 4 and each connecting at their other end into a second inflatable portion 7 of the airbag arranged to present a substantially continuous face 7A, when inflated, to receive a passenger impact from a passenger sitting in the seat behind.

It will be noted that, in the embodiment shown, the tubes 6 are separated from one another to form a skeletal arrangement airbag, thereby substantially reducing the volume of air required, compared with conventional airbags, for inflation. The first portion 5 of the airbag 3 forms by far the greatest proportion of the extent of the airbag 3 when inflated whilst not occupying much volume, whilst the surface area 7A and the comparatively small volume of the second portion 7 of the airbag 3 is sufficient to provide the required protection to a passenger in the seat behind.

For example, a conventional airbag requires about 50 litres of gas for inflation, whereas the present, skeletal airbag is expected to require around 3.8 litres to cover the same area at the operative face 7A and fill the tubes 6.

Calculations therefore show that the present skeletal airbag could show a reduction of 92.32% in the increased air pressure which would otherwise occur in an enclosed space such as a vehicle passenger compartment in the event of crash. It follows that this effect would be particularly pronounced if, as envisaged, the present airbag is installed in passenger vehicles of greater carrying capacity, for example coaches and aircraft. Of course, the present airbag is also suitable for incorporation in cars to protect rear passengers.

In order to constrain the tubes 6 in the required manner and to control the angle of orientation upon inflation, at least one tube constraint 8 is provided.

The desired angle of orientation of the airbag portion 7 is obtained by varying as required the lengths of individual tubes 6.

It is envisaged that, for example, eighteen air tubes 6 could be provided, each of the order of 10 mm in diameter.

The airbag portions 7 can be of 15 mm extent (thickness from front to back), and of 450 mm diameter.

It will be appreciated that various components can be designed to be replaceable, for example the airbags themselves and the gas cylinder and control valve 2.

To avoid activation of an airbag when there is no passenger in the seat behind the airbag concerned, a pressure sensor can be provided in that seat so that the airbag is only activated when the sensor detects a passenger on the seat behind.

Claims

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1. An inflatable airbag for use in a vehicle and actuable in the event of crash, the airbag having a first portion with a connecting portion for connection to a source of pressurised gas releasable into the airbag upon crash, and a second portion, remote from said connecting portion, arranged to face, and receive the impact of, a vehicle passenger upon crash; said first portion comprising a plurality of flexible, inflatable tubes each extending from said connecting portion to said second portion and said second portion presenting a substantially continuous face, when inflated, to receive a passenger impact.

2. An airbag according to claim 1, wherein the inflatable tubes are separate from one another along at least the majority of their length.

3. An airbag according to claim 1 or 2, wherein one or more tube constraints are provided to control the angle of direction of extent of the tubes upon inflation.

4. An airbag according to claim 1, 2 or 3, wherein one set of ends of the tubes of the first portion connect into the connecting portion through a manifold arrangement.

5. An airbag according to any one of the preceding claims, wherein ends of the tubes of the first portion remote from the connecting portion connect into the second portion of the airbag through a manifold arrangement.

6. An airbag according to any one of the preceding claims, wherein the correct angle of orientation of the second portion upon inflation is obtained by varied lengths of the tubes of the first portion.

7. An inflatable airbag for use in a vehicle, substantially as hereinbefore described with reference to the accompanying drawing.

8. A vehicle incorporating an inflatable airbag according to any one of the preceding claims.

9. A vehicle according to claim 8, wherein the airbag is installed in the rear of a seat to protect a person in a seat behind the firstmentioned seat.

10. A vehicle according to claim 9, wherein a sensor is provided to detect presence of a person in said seat behind and linked to means for activation of said airbag to prevent such activation in the absence of such a person.