GB2477911A

GB2477911A - A retraction arrangement

Info

Publication number: GB2477911A
Application number: GB201002091A
Authority: GB
Inventors: Fredrik Fernfors; Niklas Brunnegard; Adrian Bud; Jonas Sterner; Ulf Magnusson
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2010-02-09
Filing date: 2010-02-09
Publication date: 2011-08-24
Also published as: GB201002091D0

Abstract

A safety arrangement comprising a fixed part adapted to be fixed in place relative to a vehicle, a rotating part which is rotatably mounted with respect to the fixed part, a drive arrangement adapted to drive rotation of the rotating part relative to the fixed part, and an air-bag 9, at least a part of which is attached to the rotating part, and which is adapted to be connected to a source of inflation so that the air-bag may be inflated. The rotating part may rotate about an axis either parallel or perpendicular to the air-bag attachment surface.

Description

Title: A Retraction Arrangement

Description of Invention

THIS INVENTION relates to a retraction arrangement, and in particular concerns an arrangement for retracting an air-bag cushion after inflation.

When a motor vehicle is involved in a head-on collision with a pedestrian, it is common for the body of the pedestrian to strike the windscreen of the vehicle.

This can result in serious injury to the pedestrian, and significant damage to the vehicle.

In an attempt to alleviate this, it has been proposed to provide a pedestrian air-bag which, if vehicle sensors indicate that an appropriate collision is occurring or is likely to occur, inflates to cover a central portion of the windscreen, and/or the left and right A-pillars of the vehicle. Typically, the air-bag is stored beneath a rear edge of the vehicle's bonnet, or beneath a cowl which is provided between the base of the windscreen and the rear of the bonnet. The rear of the bonnet may be lifted, by a suitable air-bag, piston or other arrangement, to allow sufficient space for the air-bag to inflate.

The aim of a pedestrian air-bag of this type is to provide an inflated cushion over the windscreen and/or A-pillars of the vehicle, thus cushioning the impact of a pedestrian with these parts of the vehicle.

One potential problem that can occur with the use of air-bags of this type is that, once the air-bag has been inflated, it is very difficult for the driver of the vehicle to see out of the front windscreen. If a vehicle collides with a pedestrian with sufficient force that the pedestrian strikes the windscreen of the vehicle, the vehicle is likely to be travelling at a considerable speed. If a pedestrian air-bag inflates while the vehicle is travelling at speed, and subsequently obscures the driver's view for a long period of time, the result may be that the driver fails to avoid one or more further objects or hazards before bringing the vehicle to a complete stop.

One solution to this problem is presented in JP 2006219046. This document discloses a pedestrian air-bag which has a pair of straps, which are attached to upper left and right corners of the air-bag. As the air-bag inflates the straps are drawn from a spring-biased reel, with the biasing being overcome by the inflation of the air-bag cushion itself. Once the air-bag has been inflated, however, the reel rotates to retract the straps, thereby drawing the deflating air-bag off the windscreen and allowing the driver to see clearly out of the windscreen once more.

It is an object of the present invention to provide an improved system of this type.

Accordingly, one aspect of the present invention provides a safety arrangement comprising: a fixed part adapted to be fixed in place relative to a vehicle; a rotating part which is rotatably mounted with respect to the fixed part; a drive arrangement adapted to drive rotation of the rotating part relative to the fixed part; and an air-bag, at least a part of which is attached to the rotating part, and which is adapted to be connected to a source of inflation so that the air-bag may be inflated.

Advantageously, the air-bag is attached to the rotating part at at least two points separated by a distance.

Preferably, a region of the air-bag is clamped to the rotating part.

Conveniently, the rotating part has an attachment surface to which the air-bag is attached, and wherein the rotating part is mounted for rotation with respect to the fixed part about an axis that is generally perpendicular to the attachment surface.

Advantageously, the arrangement further comprises an inflation nozzle, which is adapted to deliver pressurised gas into an interior of the air-bag, and which protrudes through the rotating part.

Preferably, a first portion of the rotating element is connected to the drive mechanism, and wherein a second portion of the rotating element is spaced apart from the first portion, the air-bag being attached to the second portion.

Conveniently, the second portion is wider than the first portion.

Advantageously, the rotating part has an attachment surface to which the air-bag is attached, and wherein the rotating part is mounted for rotation with respect to the fixed part about an axis that is substantially parallel with the attachment surface.

Preferably, the nozzle delivers pressurised gas into a first chamber which is outside the air-bag, and which has a communication aperture through which gas may flow from the first chamber into the interior of the air-bag.

Conveniently, the arrangement further comprises a source of pressurised gas.

Another aspect of the present invention provides a vehicle comprising an arrangement according to the above.

In order that the present invention may be more readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which: figures 1 and 2 show a first arrangement embodying the present invention; figures 3 to 6b show a second arrangement embodying the present invention; and figures 7 to 9b show a third arrangement embodying the present invention.

Referring firstly to figures 1 and 2, a retraction arrangement 1 embodying the present invention is shown. An inflator 2 is provided, the inflator 2 taking any suitable form, such as a pyrotechnic inflator. The inflator 2 has a top surface 3 from which an elongate nozzle 4 protrudes. At a distal end 5 of the nozzle 4, diffusion apertures 6 are formed. It will be understood that, when the inflator 2 is activated, pressurised gas will flow through the nozzle 4 and out of the diffusion apertures 6.

An inner element 7 is rotatably mounted on the nozzle 4. The rotatable connection not shown may take any suitable form, for instance one or more bearings fitted between the nozzle 4 and the inner element 7.

The inner portion 7 takes a generally annular form, having an approximately circular central aperture 8 passing therethrough, in which the nozzle 4 is rotatably received, and having a generally circular outer profile.

An air-bag 9 which is to be inflated by the inflator 2 has a connection surface which is laid against the upper surface of the inner element 7, and has an inlet aperture 10 formed therethrough, through which the nozzle protrudes so that the diffusion apertures 6 lie inside the air-bag 9.

A retaining plate 11 is then placed over the upper surface of the inner element 7, so that part of the air-bag 9 is sandwiched between the inner element 7 and the retaining plate 11. The retaining plate 11 is secured to the inner element 7 by a pair of rivets 12 (in the example shown in figure 1), or by any other

suitable means.

In preferred embodiments a deflector 13 is positioned within the air-bag 9, around the diffusion nozzle 6, to help deflect high-pressure gas which is introduced into the air-bag 9 through the diffusion aperture 6 to be directed so as to inflate the air-bag 9 swiftly and effectively, as is known in the art. In preferred embodiments the deflector 13 takes the form of a raised wall which runs around the end 5 of the nozzle 6 which protrudes into the air-bag 9.

An outer element 14 is placed around the inner element 7. In preferred embodiments the outer element 14 has a central aperture 15 having an internal cross-sectional shape which substantially matches the exterior cross-sectional shape of the inner element 7. In preferred embodiments the aperture in the outer element 14 and the outer cross-section of the inner element 7 are approximately circular.

In embodiments, the inner and outer elements 7,14 may be rotationally mounted to one another, for instance by one or more bearings (not shown).

The outer element 14 is attached to the upper surface 3 of the inflator 2 (or to any other suitable part of the inflator 2, or indeed a separate, nearby fixed component), for instance by one or more rivets 16 (as in the embodiment of figure 1), or by any other suitable means. The outer element 14 is also attached to a container 34 that surrounds the outer element 14.

It will therefore be understood that the inflator 2, nozzle 4 and outer element 14 are all fixed in place with respect to one another, and that the inner element 7 is mounted rotationally with respect to all of these components.

A drive mechanism is provided to drive rotation of the inner element 7 with respect to the outer element 14. For example, with reference to figures 1 and 2, a robust wire or band 18 may be wrapped around an exterior surface of the inner element 7, and then passed through an internal passage (not shown) formed through the outer element 14, so that it protrudes out of an aperture 17 on the exterior of the outer element 14. The wire or band 18 is attached to a drawing arrangement (not shown) which can draw the band or wire 18 rapidly out of the outer element 14, thus causing rapid rotation of the inner element 7.

For instance, the drawing arrangement could comprise a spool onto which the wire or band is wound by rotation of the spool.

Any suitable alternative drive mechanism may also be used. For instance, a number of vanes or blades could protrude from the inner element 7, and a source of highly pressurised gas (for instance a pyrotechnic source) could direct a stream of gas or solid objects (such as balls) onto the vanes or blades, thus driving rotation of the inner element 7.

Use of the retraction arrangement 1 will now be described.

When the air-bag 9 is deployed, high-pressure gas will be generated by the inflator 2 and will pass through the nozzle 4, and out of the diffusion apertures 6 into the interior of the air-bag 9. The air-bag 9 will inflate, and the shape of the inflated air-bag 9 will largely depend upon the way in which the air-bag 9 is formed. If the air-bag 9 is to extend across to the windscreen of a vehicle, to protect a pedestrian in the event of a collision, the air-bag is likely to be generally planar and mattress-shaped, and to extend upwardly away from the retraction arrangement 1 As discussed above, after the air-bag 9 has served its protective purpose, it is desirable for the air-bag 9 to be removed from the vehicle's windscreen as rapidly as possible, to allow the driver of the vehicle to see objects in front of the vehicle. After a predetermined time has elapsed following deployment of the air-bag 9 or if a determination is otherwise made that the air-bag 9 no longer needs to be in front of the windscreen, the drive arrangement is activated, to drive rotation of the inner element 7. The inner element 7 then rotates rapidly, twisting the air-bag 9 (a part of which is fixed in place with respect to the inner element 7). This twisting action will tend to draw the air-bag 9 towards the retraction arrangement 1, and also to twist the air-bag 9 into a rope-like configuration. Both of these effects will allow the vehicle's driver to see more clearly out of the windscreen.

It will be appreciated that the size of the portion of the air-bag 9 which is attached to the inner element 7 will influence the speed with which the air-bag 9 is withdrawn from the vehicle's windscreen. The larger the area of the air-bag 9 that is attached to the inner element 7 (or the greater the distance between two points of the air-bag 9 that are attached to the inner element 7), the faster the rate of withdrawal will be.

For this reason, it may be desirable to mount an attachment plate 19 (shown in figure 3) to the upper surface of the inner element 7, the attachment plate 19 preferably having a larger size than the inner element 7. It will be appreciated that, in order to rotate freely with respect to the outer element 14, the attachment plate 19 will need to be raised above the level of the outer element 14, and in the embodiments shown in figure 3 this is achieved by a pair of elongate connectors 20 that extend upwardly from the upper surface of the inner element 7 and are firmly connected to the attachment plate 19.

In this embodiment a region of the air-bag 9 is once again placed on the attachment plate 19, and a retaining plate 11 is placed over the top of the air-bag 9 and secured to the attachment plate 19, for instance (as shown in figure 3) by rivets 21.

Figure 4 shows a schematic view of the retraction arrangement 1 mounted on a vehicle, shortly after deployment of the air-bag 9. The retraction arrangement 1 is mounted just in front of the lower edge of the windscreen, adjacent and/or beneath the rear edge of the bonnet, and (as is well known in the art) the rear edge of the bonnet may lift to allow deployment of the air-bag 9. In figures 4, 5a and 6a arrows show the direction of the windscreen (W) and the front edge of the bonnet (B), and a line 22 is also shown representing the front lower edge of the windscreen.

In the depicted embodiment the retaining plate 19 is of generally rectangular form, and the longer edges 23 thereof are, in an initial state, arranged to be generally parallel with the front edge of the windscreen, with the shorter edges 24 being arranged to be generally perpendicular to the front edge of the windscreen. Four seams 25 of the air-bag 9 are shown extending away from corners of the retaining plate 19, although it will be appreciated that the arrangement 1 may be used with an air-bag without seams that are provided in these particular positions.

Figures 5a and 5b show top and side views, respectively, as the retraction arrangement 1 begins to rotate, and figures 6a and 6b show corresponding views after the retaining arrangement 1 has performed a 900 rotation. It will be appreciated that, even after a rotation of only 90°, significant twisting of the air-bag 9 has already begun to occur.

In some embodiments the inner element 7 (along with the attachment plate 19) may perform only a small rotation, such as through 90°, and then stop rotating.

In other embodiments, however, the inner element 7 may perform several complete rotations, leading to substantial twisting of the air-bag 9, thus improving the driver's view as discussed above.

It will be appreciated that, if a rectangular attachment plate 1 9 is used, as shown in figures 4, 5a, 5b, 6a and 6b, the retaining arrangement 1 will need to be spaced apart from the lower edge 22 of the windscreen by a sufficient distance for the rotation to occur. For instance, if the retraction arrangement 1 is arranged in an initial state so that the longer edges 23 of the rectangular retaining plate 19 are substantially parallel with the lower edge 22 of the windscreen, the retaining plate 19 will need to be spaced apart from the windscreen to allow sufficient space for the retaining plate 19 to rotate.

Turning to figure 7, a further retraction arrangement 26 embodying the present invention is shown. This alternative embodiment, in common with the above-described embodiments, includes an inflator 2 and nozzle 4.

A container 27 is mounted above the inflator 2, the container 27 having an outer wall 28 and an inner wall 29. Both the outer and inner walls 28,29 are generally dish-shaped.

An attachment plate 19 is provided, the attachment plate 19 substantially blocking off the open top side of the inner wall 29. The inner wall 29 and the attachment plate 19 therefore form a generally enclosed chamber 30, which is substantially fluid-tight aside from an aperture 31 in a central portion of the attachment plate 19. The nozzle 4 protrudes through an aperture in the lower surface of the container 27 with the diffusion apertures 6 thereof positioned inside the chamber 30.

The attachment plate 19 is provided on a rotatable spindle 32, which is mounted for rotation in apertures formed through the outer wall 28 of the container 27. The spindle 32 runs through the attachment plate 19 and is, at least in part, generally parallel with the plane of the attachment plate 19.

As with other embodiments, a part of an air-bag 9 is placed over the top surface of the attachment plate 19, and a retaining plate 11 is then fixed to the top of the attachment plate 1 9, so that the air-bag 9 is sandwiched firmly, and held in place, between the attachment plate 19 and the retaining plate 11.

A drive arrangement 33 (which may take any suitable form) is provided to impart rotation to the spindle 32, generally about its longitudinal axis.

Figure 8 shows a schematic view of the further retraction device 26 seen end-on.

Use of the further retraction device 26 will now be described.

When the inflator 2 is activated, the inflator 2 will deliver pressurised gas through the nozzle 4 into the interior of the chamber 30. This gas will quickly make its way through the aperture 31 of the attachment plate 19, and into the interior of the air-bag 9.

Once the air-bag 9 has been inflated and served its protective purpose, the drive arrangement 33 is activated, driving rotation of the attachment plate 19 (along with the retaining plate 11, and the portion of air-bag trapped between the attachment plate 19 and the retaining plate 11).

As the attachment plate 19 rotates, the inner wall 29 of the container 27 will break and/or deform (either permanently or elastically) to accommodate the rotation. It will be understood that this rotation will rapidly wind the air-bag 9 around the attachment plate 19 as it rotates, thus swiftly retracting the air-bag 9. Figures 9a and 9b show successive stages of rotation of the attachment plate 19, again seen end-on.

Each rotation of the attachment plate 19 will gather a length of air-bag 9 that is approximately equal to twice the width of the attachment plate 19, and it will therefore be understood that embodiments of this type retract the air-bag 9 swiftly and effectively.

It will be understood that, in these embodiments the air-bag 9 may be completely withdrawn from the vehicle's windscreen, as it is wound around the attachment plate 19.

In embodiments of the invention the air-bag may have one or more ventilation arrangements to allow venting of the air from the air-bag after deployment, to allow the air-bag to be retracted. This may take the form of passive ventilation holes, or an active system for opening additional ventilation after a certain time has elapsed, for instance one or more pyrotechnic charges.

It will be appreciated that embodiments of the present invention provide effective and compact retraction devices which may be used for several different types of vehicle air-bag.

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 safety arrangement comprising: a fixed part adapted to be fixed in place relative to a vehicle; a rotating part which is rotatably mounted with respect to the fixed part; a drive arrangement adapted to drive rotation of the rotating part relative to the fixed part; and an air-bag, at least a part of which is attached to the rotating part, and which is adapted to be connected to a source of inflation so that the air-bag may be inflated.
2. An arrangement according to claim 1, wherein the air-bag is attached to the rotating part at at least two points separated by a distance.
3. An arrangement according to claim 1 or 2 wherein a region of the air-bag is clamped to the rotating part.
4. An arrangement according to any preceding claim wherein the rotating part has an attachment surface to which the air-bag is attached, and wherein the rotating part is mounted for rotation with respect to the fixed part about an axis that is generally perpendicular to the attachment surface.
5. An arrangement according to any preceding claim further comprising an inflation nozzle, which is adapted to deliver pressurised gas into an interior of the air-bag, and which protrudes through the rotating part.
6. An arrangement according to any preceding claim wherein a first portion of the rotating element is connected to the drive mechanism, and wherein a second portion of the rotating element is spaced apart from the first portion, the air-bag being attached to the second portion.
7. An arrangement according to claim 6 wherein the second portion is wider than the first portion.
8. An arrangement according to any one of claims 1 to 3 wherein the rotating part has an attachment surface to which the air-bag is attached, and wherein the rotating part is mounted for rotation with respect to the fixed part about an axis that is substantially parallel with the attachment surface.
9. An arrangement according to claim 8, wherein the nozzle delivers pressurised gas into a first chamber which is outside the air-bag, and which has a communication aperture through which gas may flow from the first chamber into the interior of the air-bag.
10. An arrangement according to any preceding claim, further comprising a source of pressurised gas.
11. A vehicle comprising an arrangement according to claim 10.
12. An arrangement substantially as hereinbefore described, with reference to the accompanying drawings.
13. Any novel feature or combination of features disclosed herein.