GB2425991A

GB2425991A - A front seat passenger air-bag

Info

Publication number: GB2425991A
Application number: GB0509657A
Authority: GB
Inventors: Karl Heinz Sommer; Klaus Peter Kuhne; Jorg Albert; Marcus Weber; Marc Schock
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2005-05-11
Filing date: 2005-05-11
Publication date: 2006-11-15
Also published as: WO2006121383A1; GB0509657D0

Abstract

A front seat passenger air-bag (2) which is to be installed in an upper part of a dashboard (3) of a motor vehicle to protect a front-seat passenger (5) in the event that a crash situation occurs. The air-bag (2) incorporates a tether (10) and controllable vent (15), with the controllable vent (15) being normally open. The tether (10) is directly responsive to movement of a front part of the air-bag (2) away from a predetermined point 24. The tether (10) is adapted to control the vent (15) to close the vent (15) when the front part of the air-bag (2) is at least a predetermined distance from the predetermined point (24). The vent (15) thus remains open during the initial stages of inflation of the air-bag (2), and is closed when the air-bag (2) is almost fully inflated, to maintain the pressure of the gas within the air-bag (2), to minimise the chances of the passenger (5) moving entirely through the space occupied by the inflated air-bag (2) and striking the dashboard (3).

Description

A FRONT SEAT PASSENGER AIR-BAG

Description of Invention

THE PRESENT INVENTION relates to a front seat passenger air-bag, and more particularly relates to a front seat passenger air-bag which incorporates a controllable vent and a tether to control the deployment of the air-bag.

Conventional front seat passenger air-bags often form part of an air-bag unit which is mounted within the dashboard of a motor vehicle, in front of a front seat passenger. In the event that the vehicle is involved in an impact, such as a front impact, the passenger is usually thrown forwardly relative to the vehicle, towards the dashboard, as a result of the forces exerted by the impact. In order to try to prevent the passenger from moving sufficiently forwardly to strike the dashboard, potentially causing injury, the air-bag unit is actuated to inflate the air-bag to provide a cushion between the passenger and the dashboard. The passenger is thus cushioned by the inflated air-bag as the passenger moves relative to the dashboard, with energy being absorbed by the air- bag. In most cases, the passenger will be decelerated sufficiently so that the passenger is stationary relative to the dashboard and spaced apart from the dashboard, thus potentially avoiding injury from striking the dashboard.

Conventional front seat passenger air-bags are usually designed to protect a passenger that is seated in a normal upright position with their back against the back rest of the vehicle seat. In this case, the head and chest of the passenger will be spaced apart from the dashboard and the air-bag.

However, if the passenger is sitting out-of-position, for instance by leaning forwardly when the impact occurs, there may only be a short distance between the passenger and the dashboard, with the head of the passenger being close to the dashboard, and hence close to the air-bag unit. This potentially creates a very dangerous situation, as the passenger's head will be close to the air- bag during the initial stages of inflation of the air-bag, when the air- bag is expanding very rapidly. The rapidly expanding air-bag may thus strike the face of the occupant with a substantial force, and then tend to bend the neck of the passenger backwards, possibly causing injury.

In order to try to minimise injury to such an out-of-position seat occupant, it has been proposed previously to incorporate a vent into the air-bag to allow gas to escape from the air-bag as it is inflated. In this case, if the passenger's head is close to the air-bag during the initial stages of inflation of the air-bag, the air-bag will contact the head of the passenger, and instead of exerting a very large rearward force on the passenger, gas will be vented more rapidly by the vent. The pressure of the gas within the air-bag is thus reduced as the gas is vented and the forces exerted by the air-bag on the head of the passenger are reduced, thus minimising injury.

Providing a front seat passenger air-bag with a vent, is thus an effective way of minimising the chances of an out-of-position passenger being injured by the air-bag.

However, in the majority of cases, when the passenger is sitting in a normal upright position, the vent in the air-bag actually results in the degree of protection offered by the air-bag being reduced. The reason for this is that the gas from within the air-bag will continue to be vented as the air-bag is inflated to its full size, meaning that the pressure of the gas within the air-bag when it is fully inflated will be significantly less than the pressure in an equivalent air- bag with no vent. This reduced pressure means that the air-bag will not be able to provide adequate cushioning to absorb energy from the passenger.

Furthermore, the presence of the vent will mean that when the passenger moves against the fully inflated air-bag, the force exerted by the passenger on the air-bag will cause the gas within the air-bag to be vented very rapidly out through the vent. This may cause the passenger to move right through the space occupied by the fully inflated air-bag, and to strike the dashboard through the air-bag, potentially facing serious injury.

The present invention seeks to provide an improved front seat passenger air- bag.

According to the present invention, there is provided a front seat passenger air-bag which incorporates at least one tether and a controllable vent, the tether being positioned so as to lie substantially along a central vertical plane of the air-bag when the air-bag is inflated, the air-bag having a front part which is configured, upon inflation of the air-bag, to contact the chest of a front seat passenger, the tether being directly responsive to movement of the said front part of the air-bag away from a predetermined point, the tether being adapted to control the vent to close the vent when the front part of the air-bag is at least a predetermined distance from the said predetermined point.

In one embodiment the said tether is fixed at one end at a first attachment site, and the said tether is slideably retained beneath a fabric loop at a second attachment site, one of the said attachment sites being on the said front part of the air-bag, and the other of the said attachment sites being, upon inflation of the air-bag, at the said predetermined point.

In another embodiment the said first said attachment site is on the said front part of the air-bag, and the said second attachment site is, upon inflation of the air-bag, adjacent the said predetermined point.

In a further embodiment the said second attachment site is on the said front part of the air-bag, and the said first attachment site is positioned to be, upon inflation of the air-bag, adjacent the said predetermined point.

In a still further embodiment the tether has a first section and a second section, with one end of the first section being fixed at a first attachment site that is, upon inflation of the air-bag adjacent the said predetermined point, the other end of the first section being fixed at a second attachment site on the said front part of the air-bag, the second section of the tether being connected to the first section of the tether at a point which is substantially at the mid-point along the length of the first section of the tether.

Preferably the said predetermined point is positioned so as to be level with a lower part of the torso of a passenger to be protected by the airbag.

Conveniently the said predetermined point positioned so as to be level with an upper part of the torso of a passenger to be protected by the airbag.

Advantageously the front-seat passenger air-bag is provided in an upper part of the dashboard of a motor vehicle, on the front passenger side of the vehicle.

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 diagrammatic side view of a front seat passenger air-bag in accordance with a preferred embodiment of the present invention, with the air- bag being installed in a dashboard of a vehicle, and a front seat passenger seated in an upright position, FIGURE 2 is a view corresponding to Figure 1 during an initial stage of inflation of the air-bag, FIGURE 3 is a diagrammatic perspective view of an adaptable vent in accordance with the preferred embodiment of the invention, with the vent being in an open condition, FIGURE 4 is a view corresponding to Figure 2, with the vent being in a closed condition, FIGURE 5 is a view corresponding to Figure 1, with the air-bag having been inflated fully, FIGURE 6 is a view corresponding to Figure 5, but of an air-bag in accordance with an alternative embodiment of the invention, FIGURE 7 is a view corresponding to Figure 5, but of an air-bag in accordance with a further embodiment of the invention, FIGURE 8 is a view corresponding to Figure 5, but of an air-bag in accordance with a yet further embodiment of the invention, and FIGURE 9 is a view corresponding to Figure 5, but of an air-bag in accordance with a still further embodiment of the invention.

Referring initially to Figure 1, an air-bag unit 1 which incorporates a front seat passenger air-bag 2 in accordance with a preferred embodiment of the invention, is installed in a dashboard 3 of a motor vehicle. The air-bag unit 1 is positioned beneath the upper surface of the dashboard 3, close to the windscreen 4 of the vehicle. The air-bag unit 1 is situated on the front passenger side of the vehicle, so as to be in front of a passenger 5 when the passenger 5 is seated on a front seat 6 of the vehicle. It is to be appreciated that when the passenger 5 is seated in a normal upright position (as seen in Figure 1) the head 7 of the passenger 5 is far away from the air-bag unit 1.

The air-bag unit 1 is connected to a control unit 8, and the control unit 8 is connected to a crash sensor 9. In the event that the vehicle is involved in a crash, such as a front impact, the crash sensor 9 senses the crash and provides a signal to the control unit 8. The control unit 8 then provides an actuation signal to the air-bag unit I to inflate the air-bag 2 to protect the passenger 5.

Referring now to Figure 2 the air-bag 3 is shown partially inflated. The air- bag 2 incorporates a tether 10 which is positioned so as to lie substantially along a central vertical plane of the air-bag 2, when the air-bag 2 is inflated.

The tether 10 is fixed at one end to part of the air-bag 2 at a first attachment site 11 (with the part of the air-bag 2 remaining folded during the initial stages of inflation, as seen in Figure 2). The tether 10 has a first section 12 which extends from the first attachment site 11 to a second attachment site 13. The second attachment site 13 is n the form of a fabric loop which is sewn to a front part of the air-bag 2 which is configured, upon inflation of the air-bag 2, to contact the chest of the front seat passenger 5. The tether 10 has a second section 14 which extends from the second attachment site 13 to an adaptable vent 15.

Referring now to Figure 3, the adaptable vent 15 is normally open, and allows gas to escape from within the air-bag 2, out from an aperture 16 formed in the air-bag 2. A fabric retainer strip 17 is sewn at each end to the air-bag 2 along seams 18. The retainer strip 17 is positioned so as to overlie the aperture 16 in the air-bag 2. The retainer strip 17 incorporates an aperture 19 in its centre, which is aligned with the aperture 16 in the air-bag 2.

A fabric shutter strip 20 is attached to the air-bag 2 by stitching 21 at a location spaced from one side of the aperture 16. The shutter strip 20 extends from the stitching 21, underneath the retainer strip 17. The shutter strip 20 incorporates a further aperture 22 which, when the airbag 2 is in a normal condition, is aligned with the aperture 16 in the air-bag 2, and the aperture 19 in the retainer strip 17. When the adaptable vent 15 is in its normal, open, condition, as seen in Figure 3, the shutter strip 20 defines a loop of slack fabric 23 between the stitching 21 and where the shutter strip 20 extends under the retainer strip 17. The shutter strip 20 extends under the retainer strip 17, and out from the side remote from the stitching 21, to be attached to the second section 14 of the tether 10.

It is to be appreciated that if tension is applied to the tether 10 in the direction generally indicated by the arrow T, the slack fabric 23 of the shutter strip 20 will be pulled underneath the retainer strip 17. As shutter strip 20 is pulled, the slack fabric 23 is pulled taut, and the aperture 22 is moved away from the aperture 16 in the air-bag 2. Thus, it can be seen, from Figure 4, that as the slack fabric 23 is pulled taut, the shutter strip 20 forms a cover which closes the aperture 16, hence closing the adaptable vent 15.

Turning now to Figure 5, it can be seen that when the air-bag 2 is fully inflated, the air-bag 2 fills the space between the chest of the passenger 5 and the dashboard 3. When the air-bag 2 is fully inflated the second attachment site 11 has moved to a predetermined position which is adjacent to a predetermined point 24 on the dashboard 3. In this preferred embodiment the predetermined point 24 is positioned on a front part of the dashboard 3 at a relatively low level, with the predetermined point 24 being opposite a lower part of the torso of the passenger 5.

When the first attachment site 11 is adjacent the predetermined point 24 on the dashboard 3, the first attachment site is a predetermined distance from the front part of the air-bag 2 which contacts a chest of the passenger 5. When the first attachment site 11 is at the predetermined distance from the front of the air-bag 2, the first section 12 of the tether 10 is pulled taut by the inflating air-bag 2. When the first section 12 of the tether 10 is pulled taut, the tether is pulled through the fabric loop which forms the second attachment site 13, such that tension is applied along the second section 14 of the tether 10 in the direction indicated by the arrow T. This tension in the tether 10 acts upon the shutter strip 20 of the adaptable vent 15, to pull the slack fabric 23 taut, to close the vent 15.

Thus, it is to be appreciated that the tether 10 is directly responsive to movement of the front part of the air-bag 2 away from the predetermined point 24. The tether 10 is adapted to control the vent 15 to close the vent 15 when the front part of the air-bag 2 is at least the predetermined distance from the predetermined point 23. The arrangement is such that the tether 10 only controls the vent 15 to close the vent 15, when the air-bag 2 is almost fully inflated between the dashboard 3 and the chest of a passenger 5 who is sitting in a normal upright position. When the adaptable vent 15 is closed, the passenger 5 can move against the air-bag 2, without gas being vented rapidly from the vent 15, which results in the air-bag 2 providing the correct degree of cushioning to protect the passenger 5.

The relatively low positioning of the predetermined point 24 to which the first attachment site 11 moves ensures that the upper part of the air-bag 2 inflates sufficiently with the vent 15 being open, before the first attachment site 11 reaches the predetermined point 24 where the tension on the tether 10 closes the vent 15. It is to be appreciated that the height at which the predetermined point 24 is positioned relative to the air-bag unit I effectively determines when, during inflation of the air- bag 2, the tether 10 becomes taut, thus closing the vent 15.

In the event that the passenger 5 is leaning forwardly, so that the chest of the passenger 5 is closer to the dashboard 3, the air-bag 2 will be inflated but the shorter distance between the chest of the passenger 5 and the dashboard 3 will result in the distance between the predetermined point 24 and the front of the air-bag 2 being less than the required predetermined distance. In this case, minimal tension Twill be applied to the first section 12 of the tether 10, which will result in, at most, only a very small tension T being applied to the second section 14 of the tether 10, and hence to the shutter strip 20 of the vent 15. This low tension Twill not be sufficient to pull the slack fabric 23 taut, and thus the aperture 22 in the relatively long fabric strip 20 will remain aligned with the aperture 16 in the air-bag 2, with the vent remaining open.

Therefore, gas will be vented rapidly out from within the air-bag 2, as the out- of-position passenger 5 moves against it, instead of the air-bag exerting a large force on the head 7 of the passenger 5. This may minimise injury to the passenger 5.

Whilst, in the preferred embodiment described thusfar, the predetermined point 24 is positioned at a relatively low position on the front of the dashboard 3, in an alternative embodiment the predetermined point 24 may be higher up the front of the dashboard 3, as seen in Figure 6. In this alternative embodiment the tether 10 is of a shorter length than the tether 10 of the preferred embodiment described above, and thus the first and second attachment sites 11,13 are positioned at a higher level inside the air-bag 2, when the air-bag 2 is inflated. The higher level of the attachment sites 11,13 and the higher level of the predetermined point 24 on the dashboard 3, means that the first attachment site 11 is moved to be adjacent the predetermined point 24 at an earlier stage during the inflation of the air-bag 2 than in the preferred embodiment described above.

Therefore, persons skilled in the art will understand that the positioning of the predetermined point 24 at a higher level on the front of the dashboard 3 results in the tether 10 being directly responsive to movement of the front part of the air-bag 2 at an earlier stage during the inflation of the air-bag 2. Thus, the tether 10 is adapted to control the vent 15 to close the vent 15 when the front part of the air-bag 2 at least a predetermined distance from the predetermined point 24, which, in this alternative embodiment, occurs at an early stage during the inflation of the air-bag 2. Thus, the configuration of this alternative embodiment is chosen such that the vent 15 is closed before the lower part of the air-bag 2 is fully inflated. This alternative embodiment may thus be chosen to offer protection to a passenger in a vehicle which is more likely to be travelling at a very high speed, where the passenger 5 is likely to move forwardly from a normal upright position to contact the air-bag 2 before the lower part of the air-bag 2 has had time to inflate.

It is to be understood that the height of the predetermined point 24 on the front of the dashboard 3 may vary between embodiments of the invention, with different heights of the predetermined point 24 being chosen to offer different protection characteristics for the air-bag 2.

Referring now to Figure 7, a further embodiment of the invention has all of the same structural features as that of the preferred embodiment described above, but in this further embodiment the positions of the first attachment site and the second attachment site are interchanged with one another.

Therefore, in this further embodiment, it is the fabric loop of the second attachment site 13 which moves to be adjacent the predetermined point 24 on the dashboard 3, as the air-bag 2 is inflated. The first attachment site 11 is positioned on the front part of the air-bag 2 which, upon inflation of the air- bag 2 contacts the chest of the passenger.

The air-bag 2 of this further embodiment operates in the same manner as the air-bag 2 of the preferred embodiment described above. However, in this further embodiment the first attachment site 11 is moved away from the predetermined point 24 as the air-bag is inflated, with the tether 10 being directly responsive to the movement of the first attachment site 11 and hence the front part of the air-bag away from the predetermined point 24. When the first attachment site 11 has moved by a predetermined distance away from the predetermined point 24, the tether 10 becomes taut and tension is applied to the shutter strip 20 of the vent 15 to close the vent 15.

Once again, in this further embodiment, the height of the predetermined point 24 on the dashboard 3 can be selected to alter the protection characteristics of the air-bag 2.

Referring now to Figure 8 a yet further embodiment of the invention has a tether 10 which is of substantially T shape. The tether 10 of this yet further embodiment has a first section 12 and a second section 14 which are each similar to respective sections 12 and 14 of the preferred embodiment described above. However, in this yet further embodiment the second section 14 of the tether 10 is joined to the first section 12 at a mid-point along the length of the first section 12, to form an inverted T shape when the air-bag 2 is inflated.

One end of the first section 12 of the tether 10 is fixed to part of the air-bag 2 at the first attachment site 11 in a similar manner to the preferred embodiment described above. However, instead of the other end of the first section 12 being attached to a front part of the air-bag 2 by a loop, the other end of the first section 12 of the tether 10 is fixed to the front part of the air-bag 2 by stitching.

When the air-bag 2 of this yet further embodiment of the invention is inflated, the first attachment site 11 moves to a position adjacent the predetermined point 24 on the dashboard 3. As the lower part of the airbag 2 is inflated fully the first attachment site 11 and the second attachment site 13 are moved away from one another, causing the first section 12 of the tether 10 to be pulled taut. As the first section 12 of the tether 10 is pulled taut, tension is applied to the second section 14, which results in the second section 14 pulling the shutter strip 20 of the vent 15 to close the vent 15. Therefore, it is to be appreciated that in this yet further embodiment of the invention the tether 10 is directly responsive to movement of the second attachment site 13, and hence the front part of the air-bag 2, away from the predetermined point 24.

Referring now to Figure 9, a still further embodiment of the invention has the same structural features as the further embodiment shown in Figure 8 and described above, but in this still further embodiment the predetermined point 24 is positioned at a higher level on the front of the dashboard 3. This higher positioning of the predetermined point 24 means that the first attachment site 11 reaches the predetermined point 24 at an earlier time during the inflation of the air-bag 2. Thus the first section 12 of the tether 10 is pulled taut, which pulls the second section 14, closing the vent 15 at an earlier stage of the inflation of the air-bag 2.

Hence, as with the other embodiments described above, the protection characteristics of the air-bag 2 of this still further embodiment can be chosen by selecting the height of the predetermined point 24 relative to the air-bag unit 1.

It is to be understood that whilst, in the description given above, one particular type of controllable vent has been disclosed, in further embodiments of the invention, the controllable vent may take different forms. For example, in one embodiment of the invention the vent may be in the form of a tube which is associated with a cord, the cord surround the tube and being mounted on the tube in such a way that tension applied to the cord will close the tube. In this way a normally open vent through the tube may be closed as a result of tension being applied to the cord, which constitutes a tether. Of course, other types of controllable vents can he envisaged.

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.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

Claims 1. A front seat passenger air-bag which incorporates at least one

tether and a controllable vent, the tether being positioned so as to lie substantially along a central vertical plane of the air-bag when the airbag is inflated, the air-bag having a front part which is configured, upon inflation of the air-bag, to contact the chest of a front seat passenger, the tether being directly responsive to movement of the said front part of the air-bag away from a predetermined point, the tether being adapted to control the vent to close the vent when the front part of the air-bag is at least a predetermined distance from the said predetermined point.
2. A front seat passenger air-bag according to Claim 1, wherein the said tether is fixed at one end at a first attachment site, and the said tether is slideably retained beneath a fabric ioop at a second attachment site, one of the said attachment sites being on the said front part of the air-bag, and the other of the said attachment sites being, upon inflation of the air-bag, at the said predetermined point.
3. A front seat passenger air-bag according to Claim 2, wherein the said first said attachment site is on the said front part of the air-bag, and the said second attachment site is, upon inflation of the air-bag, adjacent the said predetermined point.
4. A front seat passenger air-bag according to Claim 2, wherein the said second attachment site is on the said front part of the air-bag, and the said first attachment site is positioned to be, upon inflation of the airbag, adjacent the said predetermined point.
5. A front seat passenger air-bag according to Claim 1, wherein the tether has a first section and a second section, with one end of the first section being fixed at a first attachment site that is, upon inflation of the air-bag adjacent the said predetermined point, the other end of the first section being fixed at a second attachment site on the said front part of the air-bag, the second section of the tether being connected to the first section of the tether at a point which is substantially at the mid-point along the length of the first section of the tether.
6. A front seat passenger air-bag according to any one of the preceding Claims, wherein the said predetermined point is positioned so as to be level with a lower part of the torso of a passenger to be protected by the air-bag.
7. A front seat passenger air-bag according to any one of Claim I to 5, wherein the said predetermined point positioned so as to be level with an upper part of the torso of a passenger to be protected by the air-bag.
8. A motor vehicle being provided with the front-seat passenger air-bag of Claim I in an upper part of a dashboard of the vehicle on the front passenger side of the vehicle.
9. A front seat passenger air-bag substantially as herein described with reference to and as shown in Figures 1 to 5 of the accompanying drawings.
10. A front seat passenger air-bag substantially as herein described with reference to and as shown in Figure 6 of the accompanying drawings.
11. A front seat passenger air-bag substantially as herein described with reference to and as shown in Figure 7 of the accompanying drawings.
12 A front seat passenger air-bag substantially as herein described with reference to and as shown in Figure 8 of the accompanying drawings.
13. A front seat passenger air-bag substantially as herein described with reference to and as shown in Figure 9 of the accompanying drawings.
14. Any novel feature or combination of features disclosed herein.