GB2427389A

GB2427389A - An airbag with two regions separated by a sealing element

Info

Publication number: GB2427389A
Application number: GB0512733A
Authority: GB
Inventors: Thomas Reiter; Marcus Weber; Karl-Heinz Sommer; Marc Schock; Jorg Albert; Klaus-Peter Kuehne
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2005-06-22
Filing date: 2005-06-22
Publication date: 2006-12-27
Anticipated expiration: 2025-06-22
Also published as: GB2427389B; GB0512733D0

Abstract

A safety device in the form of an air-bag unit (6) to be mounted beneath the dashboard (2) of a motor vehicle to offer protection to an occupant of the vehicle in the event that a crash situation occurs. The air-bag unit (6) has a housing (7) into which an air-bag (22) is folded. The air-bag (22) is divided into a first region (32) and a second region (33) by a sealing element (25). The first region (32) is folded in an upper part of the housing (7), and a gas generator (17) is mounted to the housing (7) to supply gas into the first region (32). The sealing element (25) defines a sealing gap at its edge between the sealing element (25) and part of the housing (7). In the event that the gas generator (17) is actuated, gas is injected into the first region (32) to inflate the air-bag 22 out from the dashboard (2). Material from the second region (33) of the air-bag (22) is pulled through the sealing gap to form the first region (32) of the air-bag (22) with the substantially gas-tight seal remaining intact (See figure 2). The sealing element may be located within or outside the air-bag (figure 4), and may comprise more than one part (figures 6 to 8).

Description

A SAFETY DEVICE Description of Invention THE PRESENT INVENTION relates to a safety device, and more particularly relates to a safety device in the form of an air-bag unit to be mounted in a vehicle, to protect an occupant of the vehicle in the event that an accident occurs. Air-bag units have been proposed previously to be mounted underneath an upper surface of a vehicle's dashboard. Such air-bag units are usually positioned beneath a moveable door which might be formed integrally with the dashboard to seal an upper end of the air-bag unit. Air-bag units of this type usually have a chamber into which an air-bag is folded, with a gas generator attached to one wall of the chamber to supply gas into the air-bag. In the event that the air-bag unit is actuated to protect an occupant in an accident situation, the gas generator generates gas which inflates the air-bag. The air-bag starts to inflate rapidly within the air-bag unit, and as the air-bag expands the air-bag exerts a large force on the walls of the chamber and the underside of the moveable door. The moveable door and the walls of the chamber must therefore be constructed from a strong material, so as to withstand the large force exerted by the air-bag. However, the moveable door is mounted to the dashboard by a hinged portion which allows the moveable door to pivot open to allow the air-bag to inflate out from an opening in the dashboard which is normally closed by the moveable door. It is most important that the walls of the chamber of the air-bag unit remain intact during the inflation of the air-bag, so that as the air-bag inflates it is directed towards the moveable door. In order for the walls of the chamber to be able to withstand the large force exerted by the inflating air-bag, the walls of the chamber are often made from a strong material, or from relatively thick sections of a material. This strong, or thick material is expensive to produce, and usually results in the walls of the chamber of the air-bag unit being relatively heavy, thus raising the cost and overall weight of the safety device. The present invention seeks to provide an improved safety device. According to one aspect of the present invention, there is provided a safety device to be mounted in a motor vehicle, the safety device incorporating an air-bag, a source of gas, a housing and at least one sealing element, at least one edge of the at least one sealing element defining a sealing gap, the material forming the air-bag extending through the gap, material of the air-bag on one side of the sealing gap forming a first region of the air-bag and material of the air-bag on the other side of the sealing gap initially forming a second region of the air-bag, the sealing gap defining a substantially gas-tight seal between the first region of the air-bag and the second region of the air-bag, and material from the second region being moveable through the sealing gap with the substantially gas-tight seal remaining intact,material forming the first region of the air-bag being stored within the housing with the source of gas being connected to inject gas into the first region to inflate the first region, the arrangement being such that when gas is injected into the first region material from the second region is pulled through the sealing gap on inflation of the first region, so that the first region expands to incorporate material from the second region as the air-bag becomes fully inflated. Preferably the safety device incorporates a further housing in which the second region of the air-bag is stored. In one embodiment the further housing has a plurality of storage parts for the second region of the air-bag, with a respective part of the second region of the air-bag being stored into each respective said storage part. Preferably the said storage parts are spaced apart from one another, with the gas generator being mounted to the housing so that substantially all of the gas generator is positioned between two of the said storage parts. Conveniently one storage part is larger than another storage part, and the part of the second region of the air-bag stored in one storage part is larger than the part of the second region stored in the other storage part. Advantageously the at least one sealing element is positioned within the airbag. Preferably the at least one sealing element is positioned outside of the airbag. Conveniently the sealing gap is defined between the at least one sealing element and part of the housing. In another embodiment the at least one sealing element is a two-part sealing element the sealing gap being defined between one part of the at least one sealing element and another part of the at least one sealing element. Preferably the edge of one of the said parts is provided with a hook-like formation which defines a recess which receives an edge of the other said part of the sealing element. Conveniently each of said parts is provided with an upstanding lip, the two upstanding lips forming the sealing gap. In a further embodiment the at least one sealing element is formed integrally with a mounting plate, with the mounting plate being positioned so as to trap part of the air-bag to produce a substantially gas-tight seal between that part of the air-bag and a part of the housing. Preferably the at least one sealing element is of a rigid material. In a yet further embodiment the at least one sealing element is at least partly defined by a curved element. Preferably the at least one sealing element incorporates a sealing lip, with the sealing gap being defined between a surface of the sealing lip and an adjacent surface. According to another aspect of the present invention there is provided a safety device as defined above mounted in a motor vehicle. According to a further aspect of the present invention, there is provided a dashboard to be installed in a motor vehicle, the dashboard incorporating the safety device as defined above. 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 sectional view of a safety device, in accordance with a preferred embodiment of the invention, which is mounted beneath part of a dashboard of a motor vehicle, with the safety device in a normal condition, FIGURE 2 is a view corresponding to Figure 1, showing the safety device during an initial stage after actuation, with part of an air-bag having inflated out from the dashboard, FIGURE 3 is a view corresponding to Figure 1, showing the safety device during a later stage after actuation, FIGURE 4 is a diagrammatic sectional view of a safety device in accordance with an alternative embodiment of the invention,FIGURE 5 is a diagrammatic sectional view of a safety device in accordance with another embodiment of the invention, FIGURE 6 is a diagrammatic sectional view of a safety device in accordance with a further embodiment of the invention, FIGURE 7 is a diagrammatic sectional view of a safety device in accordance with a yet further embodiment of the invention, and FIGURE 8 is a diagrammatic sectional view of safety device in accordance with a still further embodiment of the invention. Referring initially to Figure 1, a safety device 1 in accordance with a preferred embodiment of the invention is mounted beneath part of a dashboard 2 of a motor vehicle. The part of the dashboard 2 is horizontal, and forms a front part of the dashboard, close to the windscreen of the vehicle. The safety device 1 is positioned beneath a moveable door 3 which is formed integrally with the dashboard 2. The moveable door 3 is generally rectangular in shape, with the rear and side edges of the moveable door 3 being defined by a split line 4, that is formed by a line of mechanical weakness in the dashboard 2. The frontmost edge of the moveable door 3 is defined by a weakened hinge section 5 of the dashboard 2, with the weakened hinge section 5 being of sufficient thickness to allow the moveable door 3 to pivot about the weakened hinge section 5 in a hinging manner. The safety device 1 is in the form of an air-bag unit 6. The air-bag unit 6 has a housing 7, and some parts of the housing 7 are constructed from a relatively thin plastic material. The housing 7 has a generally rectangular planar base 8 which has front and rear edges which are connected respectively to a front upstanding wall 9 and a rear upstanding wall 10. The rear upstanding wall 10 is approximately one and a half times the length of the front upstanding wall 9. An inclined section 11 is connected to the upper edge of the rear upstanding wall 10 so as to extend rearwardly and upwardly from the rear upstanding wall 10 to meet a rear mounting flange 12. The rear mounting flange 12 defines a generally horizontal plate which, when the safety device 1 is installed in a motor vehicle, is mounted to the underside of the dashboard 2. A front edge of the rear mounting flange 12 is positioned in alignment with or beneath the rear split line 4 in the dashboard 2. The upper edge of the front upstanding wall 9 is connected to a horizontal spacer section 13, with the horizontal spacer section 13 extending perpendicularly forwardly from the upper edge of the front upstanding wall 9. The front edge of the horizontal spacer section 13 is connected to an inclined upwardly extending support plate 14, and the support plate 14 extends at an angle forwardly and upwardly to a front horizontal mounting flange 15. The support plate 14 incorporates a support aperture 16, whose purpose will become clear from the description below. The flange 15 is secured to the underside of the dashboard 2. A rear edge of the front mounting flange 15 is positioned adjacent the weakened section 5 of the dashboard 2. The mounting flanges 12 and 15, the inclined section 11, the horizontal spacer section 13 and the support plate 14 define an upper part of the housing 7, and are each constructed so as to be relatively strong compared with the other walls of the housing 7. In this preferred embodiment the walls of the upper part of the housing 7 are constructed from thicker or stronger plastic material than the plastic material forming the lower part of the housing 7. In other embodiments the upper part of the housing 7 may be constructed from the same thickness of plastic as the lower part of the housing 7, but with the upper part of the housing 7 being provided with a reinforcing layer on its exterior to ensure that the upper part of the housing is relatively strong. The reason for making the upper part of the housing 7 relatively strong will become apart from the description below. The air-bag unit 6 is provided with a gas generator 17. The gas generator 17 has a generally cylindrical main body portion 18 and a mounting tube 19 that extends radially outwardly from one side of a mid-section of the main body 18. A generally cup shaped gas diffuser 20 is initially separate from the rest of the gas generator 17 but is adapted to be screwed to the end of the mounting tube 19. The diffuser 20 is provided with four outlet apertures 21 which each provide an outlet for gas produced by the gas generator 17. The air-bag unit 6 incorporates an air-bag 22 which, when the safety device 1 is in a normal, unactuated, condition is folded within the housing 7, as seen in Figure 1. The air-bag 22 is provided with an aperture 23 of substantially the same diameter as the support aperture 16 in the support plate 14. The air-bag unit 6 further incorporates a mount 24 comprising a mounting plate which is formed integrally with a rigid sealing element 25. The mount 24 has a vertical deflector section 26 at its upper end. An inclined mounting plate 27 depends downwardly from the lower end of the vertical deflector section 30, and the inclined mounting plate 27 is provided with a mounting aperture 28. The mounting aperture 28 has the same diameter as the support aperture 16 in the plate 14. One end of a horizontal mounting spacer section 29 is formed integrally with the lower end of the inclined mounting plate 27. The other end of the horizontal mounting spacer section 29 is formed integrally with the lower end of an upwardly inclined cover section 30 which forms part of the sealing element 25. The cover section 30 is dimensioned so as to extend from the upper end of the front upstanding wall 9 to the upper end of the rear upstanding wall 10 when the sealing element 25 is placed within the housing 7. The upper end of the cover section 30 is formed integrally with a further upwardly inclined sealing lip 31. The purpose of the sealing lip 31 will become clear from the following description. During assembly of the safety device 1, initially an upper part of the air-bag 22 is left unstitched to provide an access opening to the interior of the air-bag at an opposite point on the air-bag 22 to the inlet aperture 23. The mounting tube 19 of the gas generator 17 is initially passed through the support aperture 16 in the support plate 14, so that the main body 18 of the gas generator 17 lies adjacent the outside of the housing 7. Part of the mounting tube 19 thus extends through the support aperture 16, into the interior of the housing 7. The inlet aperture 23 of the air-bag 22 is then placed over the mounting tube 19, so that part of the air-bag 22 surrounding the aperture 23 lies adjacent the inner side of the support plate 14.The material of the air-bag 22 which forms a lower part of the air-bag 22, beneath the access opening, is then folded tightly into the lower part of the housing 7, between the base 8 and the upstanding walls 9,10. The mounting aperture 28 of the mounting plate 27 is then placed over the mounting tube 19, so that the mounting plate 27 traps the part of the air- bag 22 which surrounds the inlet aperture 23 against the support plate 14. The gas diffuser 20 is then screwed to the end of the mounting tube 19 so that an outer edge of the base of the gas diffuser 20 contacts the mounting plate 27. The gas diffuser 20 is then screwed tightly to the mounting tube 19 so that the gas diffuser 20 presses the mounting plate 27 firmly towards the support plate 14. The part of the air-bag 22 which surrounds the inlet aperture 23 is firmly secured between the mounting plate 27 and the support plate 14, and is thus attached to the housing 7.In addition to serving to attach the air-bag 22 to the housing 7, the mounting plate 27 also produces a substantially gas-tight seal between the gas generator 17 and the air-bag 22. The gas generator 17 is thus supported in position. The open part of the airbag 22 may now be stitched so that the air-bag 22 is closed. As an alternative to having part of the air-bag 22 initially unstitched the air-bag 22 may be formed around the mount 24 and the gas diffuser 20, so that these items are initially inside the air-bag 22. The mount 24 and the gas diffuser 20 may be manipulated through the material of the air-bag 22. When the mounting plate 27 is mounted in position on the housing 7 the cover section 30 of the sealing element 25 extends from the upper end of the front upstanding wall 9 of the housing 7 to the upper end of the rear upstanding wall 10. The sealing lip 31 is pressed towards the inclined section 11 of the housing 7. The side edges of the cover section 30 are pressed towards the side sections of the housing 7, and a sealing gap is defined around the edges of the sealing element 25, and beneath the sealing lip 31. The material forming the lower part of the air-bag 22 which is positioned in the lower part of the housing 7 extends upwardly through the sealing gap defined by the sealing element 25 to the upper part of the housing 7. The edges of the sealing element 25 press the material of the air-bag 22 which extends through the sealing gap against the walls of the housing 7, producing a substantially gas-tight seal between the upper and lower parts of the housing 7. However, the fabric of the air-bag 22 may move through the sealing gap without the gas sealing properties of the gap being destroyed. The sealing element 25 divides the air-bag 22 into a first region 32, defined by material above the sealing gap, and a second region 33 defined by material below the sealing gap. The first region 32 of the air-bag 22 is then tightly folded within the upper part of the housing 7. The safety device 1 is now fully assembled, and can be mounted in a motor vehicle. The safety device 1 is mounted beneath the dashboard 2 of the motor vehicle by fixing the mounting flanges 12,15 on the housing 7 to the underside of the dashboard 2, by an attachment means, such as adhesive, screws or welding. The safety device 1 is positioned beneath the dashboard 2 so that the upper side of the housing 7 is beneath the moveable door 3. In the event that the safety device 1 is actuated, for instance during in an accident situation, the gas generator 17 is actuated to supply gas to the airbag 22. As the outlets 21 of the gas generator 17 are positioned within the first region 32 of the air-bag 22, which is above the sealing element 25 of the mount 24, gas is injected into the first region 32. The gas produced by the gas generator 17 inflates the first region 32 of the air-bag 22, but as the sealing gap around the sealing element 25 produces a substantially gas-tight seal between the first region 32 and the second region 33, gas is not able to flow past the sealing gap into the second region 33 of the air-bag 22. Therefore, it is only the first region 32 of the air-bag 22 which inflates. As the first region 32 inflates, the material forming the first region 32 exerts a large outward force on the upper part of the housing 7 and the sealing element 25. The upper part of the housing 7 is thus constructed so as to be relatively strong in order to withstand this large force, with the sealing element 25 being constructed from rigid material so as to similarly withstand this large force. The surfaces of the upper part of the housing 7 and the sealing element 25 direct the inflation of the first region 32 upwardly, so that the material of the first region 32 exerts a large force on the underside of the moveable door 3. This large force on the moveable door 3 causes the split line 4 to rupture and the moveable door 3 to pivot upwardly about the weakened section 5.The moveable door 3 thus opens to form an aperture in the dashboard 2 out of which the first region 32 of the air-bag 22 can inflate, as seen in Figure 2. Due to the rigid nature of the sealing element 25, the sealing element 25 provides a rigid reinforcement layer over the parts of the housing 7 in which it is mounted. The sealing element 25 also acts as a deflector to deflect the aggressive flow of gas upwardly, towards the moveable door 3, and away from the relatively weak lower section of the housing 7. The vertical deflector section 26 of the mounting plate 24 acts as a deflector to deflect the flow of gas away from the weakened hinge section 5 of the dashboard 2. The vertical deflector section 26 thus acts to prevent the aggressive flow of gas from damaging the weakened hinge section 5, which may otherwise cause the weakened hinge section 5 to rupture, allowing the moveable door 3 to be torn from the dashboard 2. As gas continues to be injected into the first region 32 of the air-bag 22, the first region 32 expands outwardly from the top of the dashboard 2, and pulls material initially forming the second region 33 of the air-bag 22 through the sealing gap and past the edge of the sealing element 25, as seen in Figure 3. As the sealing element 25 is of a rigid material the edges of the sealing element 25 remain pressed against the material of the air-bag 22 between the sealing element 25 and the housing 7, thus maintaining the substantially gastight seal between the first region 32 and the second region 33 as the fabric of the air-bag passes through the gap. The high pressure of gas on the upper side of the sealing element 25 acts to press the sealing element 25 downwardly, into tighter contact with the material of the air-bag 22, thus helping to maintain the substantially gas-tight seal.The first region 32 of the air-bag 22 continues to inflate until all of the material of the second region 33 of the air-bag 22 has been pulled out from the lower part of the housing 7. As the air-bag 22 inflates, initially that part of the air-bag 22 that will be adjacent the windscreen emerged through the door 3, and then that part of the air-bag 22 that will engage the seat occupant emerges. The air-bag 22 thus inflates towards the seat occupant, moving to engage the seat occupant as the seat occupant begins to move forwardly relative to the seat. The air-bag 22 can therefore be inflated with the sealing gap minimising the possibility of high pressure gas produced by the gas generator 17 from passing into the lower part of the housing 7. The lower part of the housing 7 can thus be constructed from a relatively weak material as the lower part of the housing 7 is not likely to encounter large forces exerted by high pressure gas. This can substantially reduce the cost of producing the safety device 1, as weaker materials are often cheaper to produce and easier to work. Referring now to Figure 4, a safety device in accordance with an alternative embodiment of the invention has many identical parts to the parts of the preferred embodiment described above, and thus the identical parts will be referred to using the same reference numerals, and will not be re-described. In this alternative embodiment the mounting plate 27 and the sealing element 25 are separate from one another. The mounting plate 27 is mounted to the gas generator 17 in the same manner as described above. The sealing element 25 is separate from the mounting plate 24 and the sealing element 25 is provided with a downwardly extending mounting flange 34 which is formed integrally with the lower end of the cover section 30. The downwardly extending mounting flange 34 is mounted to one side of the upper end of the front upstanding wall 9 of the housing 7 to mount the sealing element 25 in position within the housing 7. The lower part of the air-bag 22 which is folded into the lower part of the housing 7 extends around the edges of the sealing element 25, but in this alternative embodiment the sealing element 25 remains on the exterior of the air-bag 22. However, the sealing element 25 of this alternative embodiment still defines a sealing gap around its edges and beneath the sealing lip 31 to divide the air-bag 22 into the first region 32 and the second region 33. The material forming a front side of the air-bag 22 is held by stitching 35 to either side of the lower end of the cover section 30 of the sealing element 25. The purpose of the stitching 35 will become clear from the description below. When the safety device 1 of this alternative embodiment is actuated, the gas generator 17 injects gas into the first region 32 of the air-bag 22 and the first region 32 inflates out from the dashboard 2 as described above. As the first region 32 inflates further, material from the second region 33 of the air-bag 22 is pulled through the sealing gap and past the edge of the sealing element 25. The stitching 35 holds the material which forms the front side of the air-bag 22 in contact with the lower end of the cover section 30 and also holds material from the front side of the air-bag 22 within the lower part of the housing 7. As the rear side of the air-bag 22 is not stitched in place, it is primarily the material forming the rear side of the air-bag 22 which is pulled through the sealing gap to define material forming the first section 32.The material forming the second region 33 of the air-bag 22 is thus pulled out from the lower part of the housing 7 until the stitching 35 prevents any further material being pulled out from the lower part of the housing 7. Again that part of the air-bag 22 which is to lie adjacent the windscreen emerges through the door 3, followed by the part of the air-bag 22 that will engage the seat occupant. Turning now to Figure 5, a safety device 1 in accordance with another embodiment of the invention is mounted beneath an angled part of the dashboard 2 of a motor vehicle. The housing 7 of this other embodiment is of similar design to the embodiments described above, but the housing 7 of this other embodiment does not incorporate a horizontal spacer section, and the housing 7 is designed to be a more upright shape. However, the front upstanding wall 9 and the rear upstanding wall 10 are angled slightly outwardly relative to the centre line of the safety device 1. The gas generator 17 is mounted directly to the front upstanding wall 9, with the gas diffuser 20 being substantially horizontal. The gas generator 17 is held relative to the front upstanding wall 9 by the gas diffuser 20 as described above, but in this embodiment, the gas diffuser 20 presses against a base plate 36 of a deflector 37. The base plate 36 has an aperture that receives the mounting 19. The base plate 36 carries a deflector wall 38 which has a major portion spaced from but parallel to the base plate 36. The lower part of the deflector wall 38 is cranked inwardly to be secured to the base plate 36. The deflector wall 38 and the base plate 36 thus effectively provide additional deflector walls below and around the sides of the gas deflector 20 which is screwed to the gas generator 17, whilst providing an open end above the gas deflector 20. The safety device 1 of this embodiment is provided with a sealing element in the form of an internal plate 39. The plate 39 is of generally L-shaped cross-section, with a relatively short and thick section 40 which is fixed to an upper end of the deflector wall 38, and a relatively thin and long cover section 41 which extends substantially horizontally and rearwardly to a position over the upper end of the rear upstanding wall 10 of the housing 7. The cover section 41 provides a section of the plate 39 which is equivalent to the cover section 26 of the preferred embodiment described above. In this embodiment the material forming the lower section 33 of the air-bag 22 is tightly folded into the lower part of the housing 7, beneath the deflector wall 38 and the cover section 41 of the plate 39. The material of the air-bag 22 extends around the edges of the plate 39, and the plate 39 provides a substantially gas-tight seal between the lower region 33 of the air-bag 22 and the upper region 32 of the air-bag 22. When the gas generator 17 of this embodiment is actuated, gas is injected into the upper region 32 of the air-bag 22, with the gas being deflected upwardly by the deflector walls 37. The upper region 32 inflates and exerts a force on the lower side of the moveable door 3 which causes the split line 4 to rupture to allow the moveable door 3 to be moved so that the air-bag 22 inflates out from the dashboard 2. As the air-bag 22 continues to be inflated, material forming the lower region 33 is pulled past the edge of the plate 39, with the substantially gas-tight seal remaining intact, in a similar manner to the preferred embodiment described above. Whilst the embodiments described thusfar have each incorporated a single sealing element, a further embodiment of the invention has two sealing elements, as shown in Figure 6. The two sealing elements define between them a sealing gap which is located substantially centrally of the air-bag housing 7. The housing 7 of this further embodiment has walls of a similar dimension to the walls of the other embodiments described above, and shown in Figure 5. This further embodiment incorporates a deflector 42 which comprises a base plate 43, with the base plate 43 being retained by the gas diffuser 20 as described above. An L-shaped sealer plate 44 is formed integrally with the base plate 43 on one side of the base plate 43, to be positioned close to the gas diffuser 20. The L-shaped sealer plate 44 extends across the housing 7 and has an upturned edge 45 at a position substantially central of the housing 7. A second sealer plate 47 has, at one side, a hook-like formation 46 that defines a downwardly open recess that receives the upturned edge 45 of the first sealer plate. The second sealer plate 47 has a cover section 48 which extends from the hook-like formation 46 across to the rear upstanding wall 10. A mounting flange 48 is formed integrally with the rear end of the second sealer plate 47, and the mounting flange 48 is mounted to an inclined section of the rear part of the housing 7. The L-shaped sealer plate 44 and the second sealer plate 47 each define a respective sealing element, with a sealing gap being defined between the upturned end 45 and the downwardly open recess of the hook-like formation 46. A lower region 33 of the air-bag 22 is folded within the lower part of the housing 7, beneath the two sealer plates. Material forming the air-bag 22 extends between the L-shaped sealer plate 44 and the second sealer plate 47 where the upturned end 45 is received within the hook shaped formed 46. A substantially gas-tight seal is produced between the sealing elements 44,47, and the second region 33 of the air-bag 22 is thus substantially sealed from the first region 32 of the air-bag 22. When the gas generator 17 of this embodiment is actuated, gas is injected into the first region 32, causing the first region 32 to inflate out from the dashboard 2 as described above.As the first region 32 inflates further, material from the second region 33 is pulled through the sealing gap between the upturned end 45 and the hook shaped formation 46 of the sealer plates, to enable the first region 32 of the air-bag 22 to be enlarged, with the substantially gas-tight seal remaining intact. Whilst the embodiments described thusfar each incorporate a gas generator 17 which is mounted to one side of the housing 7, in a yet further embodiment the gas generator 17 is mounted to the underneath of part of housing 49, as shown in Figure 7. The housing 49 of this yet further embodiment is substantially n-shaped, with a front storage part 50 and a rear storage part 51. The front storage part 50 and the rear storage part 51 each form respective storage chambers, with the storage chamber of the rear storage part 51 being of greater volume than the storage chamber of the front storage part 50. The storage chambers of the storage parts 50,51 hold respective front and rear sections of the second region 33 of the air-bag 22, when the safety device is in an initial condition. A support plate 52 extends substantially horizontally from the upper side of the front storage part 50 to the upper side of the rear storage part 51. The support plate 52 has front and rear horizontal spacer sections 53,54 which are each respectively formed integrally with the front and rear storage parts 50,51. Front and rear inclined sections of the support plate 52 are formed integrally with the horizontal spacer sections 53 and 54, and are connected together by an integrally formed gas generator support plate 55. The gas generator support plate 55 is provided with a mounting aperture 56 at its centre, through which the mounting tube 19 of the gas generator 17 extends. The mounting tube 19 of the gas generator 17 also extends through the aperture 23 of the air-bag 22 and a mounting aperture 57 in a mounting plate 58. The mounting plate 58 is a horizontal plate with an upturned deflector end 59 which forms part of its front edge. The horizontal plate 58 is provided with a mounting aperture 60. The horizontal plate 58 extends rearwardly to a downwardly inclined section 61 which is in turn connected to a mounting spacer section 62 which corresponds to the horizontal spacer section 54 of the support plate 52. The mounting plate 58 is dimensioned to correspond with the upper surface of the support plate 52, so that when the mounting plate 58 is placed over the air-bag and pressed towards the support plate 52 by the gas diffuser 20, a substantially gas-tight seal is formed around the inlet 23 of the air-bag 22. The rear edge of the mounting spacer section 62 is formed integrally with a front half 63 of a two-part rear sealing element 64. The front half 63 of the rear sealing element 64 has an upwardly inclined front cover section 65 which joins an upwardly inclined lip 66. A rear half 67 of the rear sealing element 64 has an upwardly inclined lip 68 which is formed integrally with a downwardly inclined cover section 69, with the downwardly inclined cover section 69 meeting a mounting flange 70 that mounts the rear half 67 to a rear upstanding wall of the housing 7. The two-part rear sealing element 64 defines a sealing gap between the upstanding lips 66 and 68, through which material forming the rear part of the second region 33 of the air-bag 22 can extend. The air-bag unit 6 of this yet further embodiment is provided with a front sealing element 71 which extends across the upper end of the front storage part 50 of the housing 7. The front sealing element 71 is formed integrally with a front mounting flange 72 which is mounted to a front upstanding wall of the housing 7. The front sealing element 71 has a cover section 73 with an upstanding reinforcing flange, the cover section 73 extending downwardly from the lower end of the mounting flange 72 so that the rear end of the thickened cover section 73 sits over the front horizontal spacer section 53 of the support plate 52. A sealing gap is defined between the end of the thickened cover section 71 and the horizontal spacer section 53, with material forming the front part of the second region 33 of the air-bag 22 extending from the lower part of the front storage part 50 of the housing 7. When the gas generator 17 of this embodiment is actuated, the gas generator 17 supplies gas into the first region 32 of the air-bag 22 which is folded in the upper part of the housing 7, above the sealing elements 64,71. The gas inflates the first region 32, so that the first region 32 pushes against the underside of the moveable door 3 to move the moveable door 3 and inflate outwardly from the dashboard 2. As the first region 32 of the air-bag 22 inflates material forming the second region of the air-bag 22 is pulled through the sealing gaps defined by the sealing elements 64,71. Material initially forming the second region 33 is thus pulled out from the front and rear storage parts 50,51, so that the material then forms part of the first region 32. As the front storage part 50 is of smaller volume than the rear storage part 51, the front storage part 50 holds the smaller amount of the second region 33 of the air-bag 22 when the air-bag 6 is in an initial condition. The material forming the second region 33 which is stored within the front storage part 50 is thus pulled out from the front storage part 50 before all of the material stored in the rear storage part 51. The material stored in the front storage part 50 is material which, after having been pulled through the sealing gap to form the first region 32, also defines part of the air-bag 22 which is to lie adjacent the windscreen of the vehicle. Once all of the material in the front storage part 50 has been pulled out from the front storage part 50, there is still material stored in the rear storage part 51.The material remaining in the rear storage part 51 continues to be pulled past the sealing gap defined by the rear sealing elements 64, with the material in the rear storage part 51 forming part of the air-bag 22 which is to engage the seat occupant. Thus, after an initial inflation phase, the air-bag 22 expands towards the seat occupant. Referring now to Figure 8, a still further embodiment of the invention has a housing 7 of identical dimensions to the housing 7 of the embodiment shown in Figure 7. However, in this still further embodiment the rear sealing element 64 is formed by a single curved element 74 which is formed integrally with the mounting spacer section 62 of the mounting plate 58. The curved element 74 curves upwardly from the mounting spacer section 62 and over the upper end of the rear storage part 51 in an arc to rest on a protruding part 75 of an L-shaped bracket 76. The material of the air-bag 22 extends from the rear storage part 51, between the end of the curved element 74 and the bracket 76, to the first region 32 of the air-bag 22 which is positioned in the upper part of the housing 7. A sealing gap is defined at the edges of the curved element 74. The front sealing element 71 of this embodiment has a further curved element 77 which is formed integrally with the front mounting flange 72. The further curved element 77 extends in an arc from the front mounting flange 72 at an angle downwardly to a sealing lip 78. The part of the further curved element 77 which defines the arc is of dome shaped form 79 which strengthens the front sealing element 71. The further arcuate element 77 is a resilient element which pushes the sealing lip 78 downwardly in a direction towards the front horizontal spacer section 63. A sealing gap is defined at the edges of the front sealing element 71. Material forming the second region 33 of the air-bag 22 which is stored within the front storage part 50 extends upwardly through the sealing gap to join with material in the upper part of the housing 7. In the event that the gas generator 17 is actuated, gas is supplied into the first region 32 to inflate the first region 32 outwardly from the dashboard 2. As described above, material within the front storage part 50 is pulled through the sealing gap defined by the front sealing element 71 to form part of the first region 32, and part of the air-bag 22 which is to lie adjacent the windscreen of the vehicle. Material of the air-bag 22 within the rear storage part 51 is pulled through the sealing gap defined by the rear sealing element 64 to form part of the first region 32, and to form part of the air-bag 22 which is to engage the seat occupant. Thus, again, after an initial inflation phase the air-bag 22 expands towards the seat occupant. 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

1. A safety device to be mounted in a motor vehicle, the safety device incorporating an air-bag, a source of gas, a housing and at least one sealing element, at least one edge of the at least one sealing element defining a sealing gap, the material forming the air-bag extending through the gap, material of the air-bag on one side of the sealing gap forming a first region of the air-bag and material of the air-bag on the other side of the sealing gap initially forming a second region of the air-bag, the sealing gap defining a substantially gas-tight seal between the first region of the air-bag and the second region of the air-bag, and material from the second region being moveable through the sealing gap with the substantially gas-tight seal remaining intact, material forming the first region of the air-bag being stored within the housing with the source of gas being connected to inject gas into the first region to inflate the first region, the arrangement being such that when gas is injected into the first region material from the second region is pulled through the sealing gap on inflation of the first region, so that the first region expands to incorporate material from the second region as the air-bag becomes fully inflated.

2. A safety device according to Claim 1, wherein the safety device incorporates a further housing in which the second region of the air-bag is stored.

3. A safety device according to Claim 2, wherein the further housing has a plurality of storage parts for the second region of the air-bag, with a respective part of the second region of the air-bag being stored into each respective said storage part.

4. A safety device according to Claim 3, wherein the said storage parts are spaced apart from one another, with the gas generator being mounted to the housing so that substantially all of the gas generator is positioned between two of the said storage parts.

5. A safety device according to Claim 3 or Claim 4, wherein one storage part is larger than another storage part, and the part of the second region of the air-bag stored in one storage part is larger than the part of the second region stored in the other storage part.

6. A safety device according to any one of the preceding Claims, wherein the at least one sealing element is positioned within the air-bag.

7. A safety device according to any one of the preceding Claims, wherein the at least one sealing element is positioned outside of the air-bag.

8. A safety device according to any one of the preceding Claims, wherein the sealing gap is defined between the at least one sealing element and part of the housing.

9. A safety device according to any one of the preceding Claims, wherein the at least one sealing element is a two-part sealing element the sealing gap being defined between one part of the at least one sealing element and another part of the at least one sealing element.

10. A safety device according to Claim 8, wherein the edge of one of the said parts is provided with a hook-like formation which defines a recess which receives an edge of the other said part of the sealing element.

11. A safety device according to Claim 8, wherein each of said parts is provided with an upstanding lip, the two upstanding lips forming the sealing gap.

12. A safety device according to any one of the preceding Claims, wherein the at least one sealing element is formed integrally with a mounting plate, with the mounting plate being positioned so as to trap part of the air-bag to produce a substantially gas-tight seal between that part of the air-bag and a part of the housing.

13. A safety device according to any one of the preceding Claims, wherein the at least one sealing element is of a rigid material.

14. A safety device according to any one of the preceding Claims, wherein the at least one sealing element is at least partly defined by a curved element.

15. A safety device according to any one of the preceding Claims, wherein the at least one sealing element incorporates a sealing lip, with the sealing gap being defined between a surface of the sealing lip and an adjacent surface.

16. A safety device according to any one the preceding Claims, when mounted in a vehicle.

17. A dashboard to be installed in a motor vehicle, the dashboard incorporating the safety device of any one of the Claims 1 to 15.

18. A safety device substantially as herein described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

19. A safety device substantially as herein described with reference to and as shown in Figure 4 of the accompanying drawings.

20. A safety device substantially as herein described with reference to and as shown in Figure 5 of the accompanying drawings.

21. A safety device substantially as herein described with reference to and as shown in Figure 6 of the accompanying drawings.

22. A safety device substantially as herein described with reference to and as shown in Figure 7 of the accompanying drawings.

23. A safety device substantially as herein described with reference to and as shown in Figure 8 of the accompanying drawings.

24. A dashboard substantially as herein described with reference to and as shown in the accompanying drawings.

25. Any novel feature or combination of features disclosed herein.