WO1997043146A1

WO1997043146A1 - An air-bag arrangement

Info

Publication number: WO1997043146A1
Application number: PCT/SE1997/000748
Authority: WO
Inventors: Juchem Alois
Original assignee: Autoliv Development Ab
Priority date: 1996-05-10
Filing date: 1997-05-06
Publication date: 1997-11-20
Also published as: GB2312877B; GB2312877A; GB9609753D0

Abstract

In an air-bag arrangement for use in a motor vehicle, an air-bag (20) is provided which is associated with a strap (5). The strap extends between two anchoring points (7, 11). When the air-bag is inflated, parts of the strap (31, 32, 33) are caused to follow a non-linear or convoluted path, applying tension to the strap. Either the strap can pass alternatively in front of and behind a plurality of cells (21, 22, 23...) defined by the air-bag, or the strap can be constrained to follow a zig-zag path within the interior of the air-bag. There are two preferred embodiments: one wherein the air-bag, when inflated, is located across a door opening provided in the motor vehicle; and the other wherein the strap, which is associated with the air-bag, is part of a seat-belt in a motor vehicle.

Description

"AN AIR-BAG ARRANGEMENT"

THE PRESENT INVENTION relates to an air-bag arrangement, and more particularly relates to an air-bag arrangement in a motor vehicle such as a motor car.

It is known to provide air-bags in motor vehicles, such as motor cars, which air-bags are adapted to inflate in the event that an accident should arise, to provide protection for an occupant of the vehicle.

It has been proposed to provide an air-bag which, when inflated, is located between the head of an occupant of the vehicle and a window present in a door of the vehicle. The purpose of such an air-bag is to prevent the head of the occupant of the vehicle hitting the window and also to prevent the head of the occupant from emerging through the window opening if the window should be broken, or in the lowered position.

If the air-bag is to perform the desired function of retaining the head of the occupant in the vehicle when the window has been broken, an event which frequently arises during a side impact, the air-bag must have sufficient rigidity. It is also known to provide an air bag mounted on the seat belt of a motor vehicle to provide enhanced protection for an occupant of the vehicle.

The present invention therefore seeks to provide an improved air bag arrangement.

According to this invention there is provided an air-bag arrangement for a motor vehicle, the air-bag arrangement comprising an air-bag adapted to be inflated in the event that an accident should arise and a strap, the strap having a first end secured to a first anchoring point and a second end secured to a second anchoring point, the length of the strap being greater than the linear distance between the anchoring points, the strap engaging the air- bag or means associated with the air-bag so that, on inflation of the air-bag, the strap follows a non-linear path, the air-bag being formed of two layers of fabric which form, respectively, the front of the air-bag and the back of the air-bag, the strap having successive portions which are constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag, the arrangement being such that when the air-bag is inflated, the strap is substantially tensioned.

Conveniently the strap passes through the interior of the air-bag and is constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag at selected points.

Advantageously the means provided to restrain the belt to lie adjacent the fabric forming the front of the bag and the back of the bag, comprise one or more internal loops provided within the air-bag, the strap sliding freely through the loops. In an alternative embodiment the air-bag is divided into a plurality of cells which extend substantially parallel to each other in a direction transverse to the axis of the strap, the strap passing in front or and behind successive alternate cells.

Preferably the cells are separated by webs, the belt passing through an aperture formed in each web between each adjacent pair of cells.

Conveniently the air-bag, when inflated, is located across a door opening provided in a motor vehicle, the air- bag being positioned substantially in alignment with a window opening present in a door provided in the door opening.

Preferably the length of the combination of the bag and the strap is greater when the bag is uninflated than when the bag is inflated.

Advantageously said one end of the strap is located adjacent the top of the ^,lB"-Post of the motor vehicle and said other end of the strap is located at a point on the ^»»A"-Post of the motor vehicle.

Conveniently said strap is part of a seat-belt in the vehicle, such as the lap strap.

Advantageously a pillar loop is provided on the vehicle through which the seat belt is passed, the total length of the air-bag being shorter than the linear distance between the first anchoring point and said pillar loop. Preferably a portion of the air-bag is L-shaped, the L-shaped portion being disposed at the side of the vehicle when the seat-belt is fastened, the arrangement being such that when the air-bag is inflated, one arm of the L-shaped portion is located adjacent the torso of an occupant and the other arm of the L-shaped portion is located adjacent the upper leg of the occupant.

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 perspective view of one embodiment of the invention when the air-bag is inflated,

FIGURE 2 is a sectional view taken through the embodiment of Figure 1,

FIGURE 3 is an enlarged view of part of the interior of the air-bag of Figures 1 and 2,

FIGURE 4 is a perspective view corresponding to Figure 1, but illustrating an alternative embodiment of the invention,

FIGURE 5 is a sectional view taken through the embodiment of Figure 4,

FIGURE 6 is an enlarged view of part of the air-bag shown in Figures 4 and 5, with part cut away for the sake of clarity of illustration, FIGURE 7 is a side view of an alternative embodiment of the invention when the air-bag is uninflated and an associated seat belt is in a stored position,

FIGURE 8 is a part-schematic view of the embodiment of Figure 7 when the seat belt is fastened with the air-bag uninflated,

FIGURE 9 is a sectioned view taken on the line A-A of Figure 8,

FIGURE 10 is a perspective view of the embodiment of Figure 7 when the seat belt is fastened and the air-bag is inflated,

FIGURE 11 is a view of a further embodiment of the present invention when the air-bag is in a inflated sate,

FIGURE 12, is a sectional view taken on the line B- B of Figure 11,

FIGURE 13, is a view of further embodiment of the present invention when the air-bag is in an inflated state, and

FIGURE 14, is a perspective view showing the embodiment of Figure 13 when the air-bag is inflated, and an associated seat belt is fastened.

Referring initially to Figures 1 to 3 of the accompanying drawings, one embodiment of an air-bag arrangement is illustrated. The illustrated air-bag arrangement incorporates an air-bag 1 which, when in the inflated condition (as shown) extends across a door opening 2 defined by a motor vehicle. The door opening 2 is intended to accommodate a door, and the door would have a window 3 as indicated in phantom.

The air-bag 1 is initially retained within a recess which extends across the top of the door opening, the recess being provided with a cover 4. In an initial condition of the air-bag arrangement, the air-bag and an associated strap (which will be described in more detail below) will be received within the recess and will be covered by the cover 4 so as to be unobtrusive. In the event that an accident arises and the air-bag is inflated, the air-bag 1 occupies the position illustrated in Figure 1 where the air-bag is located in the region of the top part of the door opening 2.

It can be seen that the air-bag 1 comprises a single chamber bag which is associated with a strap 5. The bag is made of fabric which defines the front of the bag - directed towards the interior of the vehicle - and the back of the bag - which lies adjacent the window. The strap 5 has a first portion 6 which is connected by means of a bolt or other fastening 7 to part of the monocoque shell of the motor vehicle at an anchoring point adjacent the top of the "B"-Post 8 of the vehicle. The strap 5 includes a further strap portion 9 which is located within the interior of the bag. A final strap portion 10 is provided which extends from another part of the bag and is connected by means of a bolt or other fastening 11 to an anchoring point on the "A"-Post of the door opening 2.

The strap 5 must have sufficient length to extend across the top of the door opening and along the "A'^Post when the bag and the strap are initially stored within the recess. Consequently, the strap has a length which is greater than the distance between the bolt 7 and the bolt 11.

As can be seen from Figure 2 and Figure 3, the strap 9 extends across the interior of the air-bag 1, when it is inflated, in a zig-zag manner. The strap 9 passes through a plurality of securing loops such as the securing loop 12 shown in Figure 3, which effectively constrain successive portions of the strap to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag, on the interior of the bag 1, at successive points on opposed sides of the bag. It is preferred that the portion 9 of the strap 5 within the bag 1 can slide freely between the loops 12, but one or more predetermined points of the strap may be secured substantially permanently to selected points on the interior of the bag 1 to provide an equivalent effect.

It is to be understood that as the air-bag 1 is inflated, the portion 9 of the strap 5 within the interior of the bag is caused to adopt the non-linear or convoluted path constituted by the zig-zag configuration which is illustrated in Figure 2, thus effectively "shortening" the strap and causing the strap to be tensioned or tightened. Thus, even though the strap in its relaxed state has a length which is greater than the distance between the bolts 7 and 11, because the portion 9 of the strap occupies the zig-zag configuration of Figure 2, nevertheless the strap is tensioned, and consequently imparts a degree of rigidity to the air-bag when in the inflated state.

The shape of the portion of the strap which has the zig-zag configuration and the shape of the bag together with the pressure of gas in the bag determine the tension applied to the strap when the bag is inflated. The greater the tension, the greater is the rigidity of the bag. If the bag is very rigid, it will be able to withstand a substantial force.

Thus, the air-bag serves to minimise any risk of the head of the occupant of the vehicle moving outwardly through the opening provided for the window 3, even if the glass forming the window has been broken.

Figures 4 to 6 illustrate a second embodiment of the invention. Those features of the two embodiments which correspond are identified by corresponding reference numerals and will not be re-described in detail.

In the embodiment of Figures 4 to 6 the air-bag 20 is formed of a plurality of discrete cells 21 to 25, which are separated by webs of fabric 26 to 29. The cells and the webs provided between the cells extend substantially vertically. Each web of fabric, such as the web 26 which is shown on an enlarged scale in Figure 6, is provided with an aperture 30.

It can be seen that the strap 5 has regions which pass in front of certain cells, such as the region 31, which passes in front of the cell 21 and the region 32, which passes in front of the cell 23. The strap has other regions, such as the region 33 which passes behind the cell 22 and the region 34 which passes between the cell 24. Thus, the strap passes alternately in front of and behind adjacent cells, the strap thus having successive portions that are constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag. The cell 21 is provided, at the edge adjacent the "B"-Post 8, with a flap 35 that defines a further aperture 36 through which the strap passes.

It is to be appreciated that the strap 5 has an initial length which is greater than the linear distance between the bolts 7 and 11, thus enabling the strap and the air-bag to be stored within the recess provided for that purpose which extends above the door opening. When the air-bag is inflated, because the strap is caused to follow a non-linear or sinuous path which alternatively passes in front of and behind the adjacent cells of the air-bag, as can be seen in Figure 5, a tension is applied to the strap, making the air-bag itself substantially rigid.

Whilst the invention has been described with reference to two embodiments, it is to be appreciated that many modifications may be effected within the scope of the invention.

The embodiments of air-bag described above may be manufactured with a one-piece weaving technique. Separate layers of fabric which form the front and rear of the air- bag are woven simultaneously and in pre-selected areas the threads from the two layers are inter-woven so that effectively in these areas, a single integral layer is formed.

Whilst air-bags in accordance with the invention have been illustrated, as extending across a single window opening, it is to be appreciated that air-bags in accordance with the invention may find other applications where it is desired to provide a substantially rigid air- bag which is, effectively, self-supporting. For example, an air-bag in accordance with the invention may be provided which, when inflated, is located adjacent the window in both the back door and the front door of a motor vehicle. Alternatively, an air-bag in accordance with the present invention may be provided which extends transversely across the passenger cabin of a motor vehicle at a location adjacent the backs of the seats provided for the driver and front passenger. Such an air-bag may minimise the risk of a rear passenger being thrown forwardly and through the windscreen of a vehicle.

In further embodiments of the present invention, the air-bag may be located on the lap strap of a vehicle seat-belt. In one such embodiment, shown in Figure 7, an air-bag 36 is provided on a vehicle seat belt 37, along the portion that forms the lap strap 38.

The seat belt 37 is secured at a first end 39 to a first anchor point at the base of the B-pillar of the vehicle. When in a stored position, as showing in Figure 7, the seat belt 37 lies substantially parallel to the B- pillar, passing through a loop 40 attached to the B-pillar near the top and then passing down the length of the B- pillar to be attached, at its second end, to a retractor 41. The retractor 41 is spring-biased so as to wind in the seat belt. The retractor 41 has a lock which locks the seat belt in response to detection of an accident.

A tongue 42 is slidably attached to the seat belt 37 between the first end 39 and the loop 40. In order to fasten the seat belt around an occupant of the vehicle, the tongue 42 is pulled and fastened in a buckle 43. The seat belt is then secured to the buckle 43 by the tongue 42 which forms a second anchor point. The length of seat belt 37 between the first end 39 and the tongue 42 then lies across the hips of the occupant and defines the lap strap 38 as shown in Figure 8.

Thus, when the seat belt is fastened around an occupant, the strap 38 is longer than the linear distance between the first anchor point at the first end 39 of the seat belt 37 and the second anchor point at the buckle 43.

The total length of the folded air-bag is shorter than the linear distance between the first anchor point 39 and the pillar loop 40. Thus, the lengths of these components mean that the lap strap 38 with the folded air- bag 36 can easily be stored adjacent the B-pillar.

In normal use, the air-bag 36 and the lap strap 38 are enclosed within a protective cover 44. The protective cover 44 prevents damage or disturbance of the air-bag 36 during storage and fastening of thee seat belt 37. Thus, when the air-bag is uninflated and an occupant is wearing the seat-belt, the protective cover 44 forms a substantially cylindrical sheath about the lap strap 38 and the folded air-bag 36. The lap strap 38 lies at the centre of the protective cover 44 with the folded air-bag 36 lying on either side of the lap strap 38 as shown in Figure 9. A split-line 45 runs longitudinally down one side of the protective cover 44.

Adjacent the first end 39 of the seat belt 37, a short pipe 46 connects the air-bag 36 to a gas generator 47. The gas generator 47 is connected to an igniter 48 which in turn is connected to accident detecting means 49.

Referring now to figure 10 which illustrates the air-bag 36 when it is inflated and the seat belt 37 is fastened around an occupant, the air-bag 36 comprises a single cell formed of two layers of air-tight fabric which form, respectively, the front of the air-bag and the back of the air-bag. The air-bag 36 has a substantially oval plan having straight, parallel long sides. The air-bag 36 has four apertures 50 to 53 which extend through the air- bag 36 arranged in a line parallel to and half-way between the long sides of the air-bag 36. The portions of the air- bag 36 defining the apertures 50 to 53 are sealed so that the air-bag 36 remains air-tight. The lap strap 38 is "woven" through the apertures 50 to 53 in a convoluted zig¬ zag configuration. Thus the lap strap 38 has successive portions which are constrained to lie adjacent the fabric forming the front of the air-bag and the fabric forming the back of the air-bag. The air-bag 36 is attached to the lap strap 37 at a rivet 79 near to the tongue 42.

Should an accident occur, the accident detecting means 49 sends a signal to the igniter 48 which is ignited to active the gas generator 47. Gas is forced through the short pipe 46 and into the air-bag 36 in order to inflate the air-bag 36. At substantially the same time, the lock in the retractor 41, locks the second end of the seat-belt 37 in place. As the air-bag 36 inflates, the force on the split-line 45 of the protective cover 44 is sufficient for the split-line 45 to tear and for the air-bag 36 to become fully inflated.

It is to be noted that, when the air-bag 36 is in the inflated state, the increased volume of the air-bag 36 means that the lap strap 38 must follow a non-linear path of greater length than the path followed by the lap strap when the air-bag was in an uninflated state. Since the second end of the seat-belt 37 is locked in place, the increase in length of the path of the lap strap 38 results in the seat-belt 37 being substantially tensioned. Therefore, the air-bag 36 acts as a seat-belt pre- tensioner. It is also to be noted that when the air bag 36 is inflated it presents a wide area through which force is applied to an occupant during deceleration of the vehicle. This reduces the pressure on the abdomen of an occupant and so lowers the likelihood of an injury occurring.

It is to be appreciated that, in an alternative embodiment of the invention the lap strap 38 could pass through the interior of the air bag 36 and be constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag by being threaded through a plurality of loops attached to the air-bag fabric.

Referring to Figures 11 and 12, an alternative embodiment of the air-bag provided on a seat-belt is shown. In this embodiment of the present invention, the air-bag comprises four cells 54 to 57 which extend substantially parallel to each other in a direction transverse to the axis of the strap 38. The four cells 54 to 57 are connected by gas pipes 80, preferably made in a one piece woven technique. The cells 54 to 57 are surrounded by webs of fabric 58 to 62. The cells 54 to 57 and the surrounding webs of fabric 58 to 62 are integrally formed in a one piece woven technique. In an alternative embodiment, each web of fabric is provided with a central aperture through which the strap 38 may pass.

It can be seen that the strap 38 has regions which pass in front of certain cells, such as region 63, which passes in front of the cell 55 and the region 64, which passes in front of the cell 57. The strap has other regions, such as the region 65 which passes behind the cell 54 and the region 66 which passes behind the cell 56. The strap passes alternately in front of and behind adjacent cells, the strap thus having successive portions that are constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag.

Referring now to Figures 13 and 14, a further embodiment of the present invention is shown. This embodiment is similar to the previous embodiment having a modified air-bag 67 arranged on the lap strap 38 of a seat- belt 37. The air-bag 67 is formed of a plurality of discrete cells 68 to 71 which are separated by webs of fabric 72 to 76. The lap strap 38 passes alternately through apertures in the webs 72 to 76 in front of and behind adjacent cells as in the previous embodiment. In this embodiment, the cell 71, which is the cell nearest to the side of the vehicle when the seat-belt 37 is fastened, is of substantially "L"-shaped form when inflated, with the corner of the "L" being located on the lap strap 38. The L-shaped cell 71 comprises a first arm 77 and a second arm 78.

In normal use the cell 71 is un-inflated. The lap strap 38 may be stored as normal and may be fastened around an occupant of the seat. Should an accident occur, the modified air-bag 67 is inflated. When the cells inflate, the substantially "L"-shaped cell 71 is inflated so that the first arm 77 protrudes substantially vertically from the lap strap 38 to be located adjacent the torso of the occupant and the second arm 78 of the substantially "L"-shaped air-bag 71 is inflated substantially horizontally to lie adjacent the upper leg of the occupant of the vehicle. Thus, the substantially "L"-shaped cell 71, when inflated, presents a protective cushion between the occupant of the vehicle and the side of the vehicle. Should the vehicle be involved in a side impact, the occupant of the vehicle is protected along the torso and upper leg by the substantially "L"-shaped cell 71.

It is to be appreciated that, in an alternative to the previous embodiment, the modified air-bag 67 could be formed from a single cell with the modified air-bag having a substantially L-shaped portion located adjacent the side of the vehicle when the seat belt 37 is fastened.

Claims

CLAIMS :

1. An air-bag arrangement for a motor vehicle, the air-bag arrangement comprising an air-bag adapted to be inflated in the event that an accident should arise and a strap, the strap having a first end secured to a first anchoring point and a second end secured to a second anchoring point, the length of the strap being greater than the linear distance between the anchoring points, the strap engaging the air-bag or means associated with the air-bag so that, on inflation of the air-bag, the strap follows a non-linear path, the air-bag being formed of two layers of fabric which form, respectively, the front of the air-bag and the back of the air-bag, the strap having successive portions which are constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag, the arrangement being such that when the air-bag is inflated, the strap is substantially tensioned.

2. An arrangement according to Claim 1 wherein the strap passes through the interior of the air-bag and is constrained to lie adjacent the fabric forming the front of the bag and the fabric forming the back of the bag at selected points.

3. An arrangement according to Claim 2 wherein the means provided to restrain the belt to lie adjacent the fabric forming the front of the bag and the back of the bag, comprise one or more internal loops provided within the air-bag, the strap sliding freely through the loops.

4. An arrangement according to Claim 1 wherein the air-bag is divided into a plurality of cells which extend substantially parallel to each other in a direction transverse to the axis of the strap, the strap passing in front or and behind successive alternate cells.

5. An arrangement according to Claim 4 wherein the cells are separated by webs, the belt passing through an aperture formed in each web between each adjacent pair of cells.

6. An arrangement according to any one of the preceding Claims wherein the air-bag, when inflated, is located across a door opening provided in a motor vehicle, the air-bag being positioned substantially in alignment with a window opening present in a door provided in the door opening.

7. An arrangement according to Claim 6 wherein the bag and strap, prior to inflation of the bag, are stored above the door opening in the roof of the vehicle.

8. An arrangement according to Claim 6 or 7 wherein said one end of the strap is located adjacent the top of the "B"-Post of the motor vehicle and said other end of the strap is located at a point on the "A"-Post of the motor vehicle.

9. An arrangement according to any one of Claims 1 to 5 wherein said strap is part of a seat-belt in the vehicle.

10. An arrangement according to Claim 9 wherein said part of the seat-belt is the lap strap.

11. An arrangement according to Claim 9 or 10 wherein a pillar loop is provided on the vehicle through which the seat belt is passed, the total length of the air-bag being shorter than the linear distance between the first anchoring point and said pillar loop.

12. An arrangement according to any one of Claims 9 to 11 wherein a portion of the air-bag is L-shaped, the L- shaped portion being disposed at the side of the vehicle when the seat-belt is fastened, the arrangement being such that when the air-bag is inflated, one arm of the L-shaped portion is located adjacent the torso of an occupant and the other arm of the L-shaped portion is located adjacent the upper leg of the occupant.