GB2364970A

GB2364970A - A method of and apparatus for folding an air-bag

Info

Publication number: GB2364970A
Application number: GB0018223A
Authority: GB
Inventors: Jan-Erik Kallhammer; Bertrand Carpentier
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2000-07-25
Filing date: 2000-07-25
Publication date: 2002-02-13
Anticipated expiration: 2020-07-25
Also published as: GB0018223D0; GB2364970B

Abstract

An apparatus for folding an air-bag (5) into a housing (4) contained within a recess (3), comprises two rotary drive means in the form of a first drive-belt (12) and a second drive-belt (13). The second drive belt (13) is biased via biasing means (18) towards the first drive-belt (12) to trap part of the air-bag (5). The drive-belts (12,13) drive the fabric of the air-bag (5) between a closure element (11) and the open top of the housing (4) so that the fabric of the air-bag (5) passes through a slot into the housing (4). The fabric is thus crumpled rather than folded.

Description

<Desc/Clms Page number 1> DESCRIPTION OF INVENTION "'IMPROVEMENTS IN OR RELATING TO A METHOD OF AND APPARATUS FOR FOLDING AN AIR-BAG" THE PRESENT INVENTION relates to a method of and apparatus for folding an air-bag, such as an air-bag intended for use to provide protection for an occupant of a motor vehicle in the event that an accident should arise.

It has been proposed previously to provide an air-bag mounted in a motor vehicle adapted to be inflated in the event that an accident should occur, the inflated air-bag being located in front of an occupant of the vehicle in order to provide protection for that vehicle occupant.

A conventional air-bag comprises a fabric bag which is initially stored within a housing. Typically the air-bag is initially laid out substantially flat, with two superimposed layers of fabric lying immediately adjacent each other, and then the air-bag is folded before it is inserted into the housing. In a conventional folding technique, the two layers of fabric are folded together simultaneously about a single fold-line when each fold is created. This has the effect of creating, within the air-bag, regions where no gas may flow since the simultaneous fold of two adjacent layers of fabric is such that no gas may flow past the fold.

This may be undesirable, in that the air-bag may possess an inappropriate inflation characteristic.

It is now proposed, therefore, to fold an air-bag into such a way that the different layers of fabric are folded or crumpled, the layers preferably being folded or crumpled at different locations, so that there is an air-flow through the entire air-bag during initial inflation thereof.

The present invention seeks to provide a method of and apparatus for folding an air-bag.

According to one aspect of this invention there is provided an apparatus for folding an air-bag, the apparatus comprising means adapted to receive and retain a housing to which an air-bag is connected and into which the air-bag is to be folded, and drive means adapted to engage parts of the fabric of the air- bag initially on the exterior of the housing to drive the fabric into the interior of the housing, the apparatus comprising means to substantially close the housing while defining a slot through which part of the air-bag passe s, the drive means being adapted to drive the fabric of the air-bag into the housing through the slot.

Preferably the drive means surround a recess which constitutes the means to receive and retain the housing.

Conveniently the drive means support the fabric of the air-bag in a substantially flat state and engage at least one side of the fabric to drive the fabric into the housing.

Advantageously the drive mean's engage at least a lower layer of fabric to drive the fabric.

in some embodiment the drive means are rotary drive means.

The rotary drive means may comprise any arrangement adapted to be rotated and having a portion thereof adapted to engage parts of the fabric of the air-bag to drive the fabric into the interior of the housing. Thus in one embodiment the rotary drive means comprise a plurality of drive-belts located about the retaining means, the drive-belts being adapted to support the fabric of the air-bag when initially laid out about the retaining means.

Preferably each said drive-belt is associated with a co-operating drive- belt the co-operating drive-belt being movable between an initial retracted position and a final operative position, the said guide belt, when in the operative position, having a lower portion thereof substantially in engagement with the upper portion of the first said drive-belt.

Advantageously means are provided to close the upper part of the housing when the fabric of the air-bag is being driven into the housing.

In an alternative embodiment the retaining means are defmed in a central region of a table and the rotary drive means comprise a plurality of driven wheels carried on a supp ort, the support being positionable above the retaining means and above the table, so that the rotary drive means engage the fabric of the air-bag.

Conveniently the table is provided with friction-reducing means to facilitate movement of the air-bag relative to the table.

Preferably the friction-reducing means comprise rollers or other rotatably mounted elements provided on the table.

In a further alternative embodiment the drive means comprise reciprocating elements which engage and drive the fabric on moving towards the housing and which are disengaged from the fabric or moving away from the housing.

In one -arrangement the reciprocating elements engage upper and lower sides of the fabric.

Advantageously an element is provided adapted to compress the fabric of the air-bag, after it has been driven into the housing by the drive means. Conveniently means are provided to move the housing into engagement with a cover after the fabric of the air-bag has been inserted into the housing. The invention also relates to a method of folding an air-bag into a housing, the method comprising the steps of locating the housing, to which part of the air-bag is connected, in retaining means, and using drive means to drive the fabric of the air-bag into the housing through a slot.

Preferably the drive means are rotary drive means which comprise a plurality of co-operating pairs of drive-belts, surrounding the means retaining the housing, the drive-belts initially receiving the fabric of the air-bag.

Alternatively the drive means are rotary drive means which comprise a plurality of drive-wheels on a support adapted to be located above the retaining means.

Alternatively the drive means are reciprocating drive means, Conveniently the method includes the preliminary step of spreading out the air-bag.

Advantageously the method includes the subsequent step of compressing the fabric of the air-bag when it is in the housing.

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 I is a perspective view of part of a folding apparatus in accordance with the invention in an initial condition thereof, FIGURE 2 is a view corresponding to Figure I illustrating the apparatus at a subsequent stage of a folding cycle, FIGURE 3 is a view corresponding to Figure 2 showing a later subsequent stage in the folding cycle, FIGURE 4 is a view corresponding to Figure 3 showing a further subsequent stage in the folding cycle,

FIGURE 5 is a view corresponding to Figure 4 showing yet another stage in the folding cycle, FIGURE 6 is a view corresponding to Figure 5 showing a final stage in the folding cycle, FIGURE 7 is a view of a modified embodiment of the invention, FIGURE 8 is a sectional view taken on the line VIII-VIII of Figure 7, FIGURE 9 is a sectional view, corresponding to part of Figure 1, showing a modified embodiment of the invention during an initial stage in the folding of an air-bag, FIGURE 10 is a view corresponding to Figure 9 at a subsequent stage in the folding of the air-bag, and FIGURE I I is a view, corresponding to Figure 10, but showing a later stage in the folding of the air-bag. Referring initially to Figure I of the accompanying drawings, a folding apparatus I in accordance with the invention comprises a folding table 2 defining, in a central region, a recess 3 dimensioned to receive and retain a housing 4 into which an air-bag 5 is to be folded. The recess 3 may, as in the illustrated embodiment, be constituted by upstanding walls 6, which extend up above the surface of the table 2, or the recess may be provided in such a way that the u pper part of the recess is flush with the upper surface of the table 2. The recess 3, in the illustrated embodiment, extends through the table and the lower part of the recess 3 is defined by a plunger 7 mounted on a piston 8

which is associated with a drive cylinder 9. The drive cylinder 9 is supported by a support arrangement 10 which depends beneath the table 2. The drive cylinder 9 may move the plunger 7 vertically. Located above the recess 3 is a recess closure element 11, which is dimensioned to substantially close the recess 3, as will be described hereinafter, while leaving a slot through which the fabric of the air-bag may be driven into a housing in the recess. Surrounding the recess 3 are a plurality of co-operating drive-belt-pairs, as exemplified by the drive-belt-pair 12, 13. The drive-belt 12 is an elongate drive-belt mounted to be driven by rollers 14, 15. The drive-belt 12 is located just above the table 2, and has an upper belt portion substantially parallel with the upper surface of the table 2. The belt 12 thus resembles a very narrow horizontal "conveyor belf'. The second belt 13 is of similar fonn, comprising a belt that is driven about two rollers 16, 17, and the belt is shown in an initial elevated position in which the belt is inclined upwardly and away from the first belt 12. The second belt 13 is slightly largeri than the first belt 12, in that the spacing between the two rollers of the second belt 13 is slightly greater than the spacing between the rollers of the first belt 12. A drive-belt biasing member 18 is provided, located adjacent the recess closure element 11. The function of the member 18 will be described below. It is to be appreciated that plurality of drive-belt pairs are provided, as exemplified by the drive-belts 12, 13, the drive-belts being located around the exterior of the periphery of the recess 3, each lower drive-belt having a terminal roller adjacent the periphery of the recess 3. The drive-belts extend generally radially, relative to the recess 3.

When the illustrated apparatus is prepared for operation, the housing 4 is located within the upper part of the recess 3. An air-bag 5, which is connected to, and which is to be folded into, the housing 4, is located in position with part of the air-bag 5 spread out on top of the lower drive-belts of the drive-belt pairs, such as the drive-belt 12. As shown in Figure 1, a gas generator or inflator 19 associated with the air-bag 5 may be located within the housing 4. The air-bag 5 is spread out substantially flat, and is thus ready for the folding operation to commence. The plunger 7 is spaced, within the recess 3, beneath the housing 4. During an initial stage of the folding process, the upper drive-belt 13 is moved pivotally, substantially about the axis of the roller 16, so that the lower band of the upper drive-belt 13 lies immediately adjacent the upper band of the lower drive-belt 12. Thus part of the air-bag 5 is trapped between the two drive-belts 12, 13. As can be seen from Figure 2, because the drive-belt 13 is slightly longer than the drive-belt 12, part of the drive-belt 13 extends over the edge of the housing 4 in the recess 3. The drive-belt biasing member 18 is lowered to push the upper drive- belt 13 downwardly into firm contact with the lower drive-belt 12 and the air- bag 5 trapped therebetween. The recess closure I I is lowered to substantially close the upper part of the recess 3. The recess closure I I is configured to receive the end part of the upper conveyor 13 which extends partly over the recess 3. Thus the recess is closed, the air-bag extending through a slot which communicates with the recess, and with a housing within the recess.

It is to be appreciated that whilst only one belt pair has been illustrated, similarly the other belt pairs will have been moved so that the upper belt is in contact with the lower belt. The drive-belts are then caused to rotate in such a sense that the upper part of the lower belt 12, and the lower part of the upper belt 13 both move towards the housing 4 contained within the recess 3. The drive-belts may be moved at the same speed, or at different speeds. Alternatively, only one drive- belt for example, the lower drive-belt 12, may be driven, with the other drive- belt 13 being free to move. As the drive-belts rotate so the fabric of the air-bag initially lying on the drive-belts is squeezed through the slot into the housing 4. The fabric forming the air-bag 5 is thus injected into the hollow interior of the housing 4 through the slot defined between the recess closure 11 and the open upper part of the housing 4. As the fabric enters the housing, the fabric will be crumpled or crushed, and it is envisaged that in large areas of the air-bag, the fabric will be crumpled or crushed in such a way that folds in one layer of fabric will be different to the folds in the immediately adjacent layer of fabric. This is the situation shown in Figure 2. When all of the fabric of the air-bag has been driven into the housing 4, the recess closure I I is pressed further downwardly, firmly compressing the folded air-bag within the housing 4, and physically driving the housing 4 downwards, within the recess 3, until the lower part of the housing 4 comes into engagement with the plunger 7. At this stage the upper drive-belt 13 may be moved upwardly to its initial position, as shown in Figure 3.

Subsequently the recess closure I I is elevated and an inverted housing cover 20 is mounted beneath the recess closure 11. The cover 20 is dimensioned to receive the housing 4.

The cover 20 is lowered, on the recess closure 11, to be aligned with the upper part of the recess 3, as shown in Figure 4. Subsequently the piston 8 is driven -upwardly, thus moving the associated plunger 7 upwardly, driving the housing and the folded bag upwardly until the housing and the fold ed bag are inserted into the cover 20, as shown in Figure 5. The cover 20 and the housing 4 may co-operate so that as the housing 4 is inserted into the cover 201 the cover is connected to the housing 4 by means of a snap action. The piston 8 and the plunger 7, may then be lowered, to their original position, as shown in Figure 6, and the fully assembled housing 4, together with the cover 20, containing the folded air-bag 5, may then be removed from the apparatus, permitting the apparatus to commence a further cycle of operation. In a modified embodiment of the invention, partially shown in Figures 7 and 8, a table 30 is provided which defines a central recess 3 1. The lower part of the recess 31 is provided with a piston, cylinder and plunger arrangement similar to that shown in Figure 1. The recess 31 is shown, in Figure 8, containing a housing 32 in which is mounted a gas generator 33 associated with an air-bag 34. The air-bag is to be folded into the housing 32. The air-bag 34 is spread out to cover the top part of the table 30. In the e1hbodiment shown in Figure 7 and Figure 8, instead of using a plurality of drive-belts to drive the air-bag into the housing, a drive assembly 36 is utilised. The drive assembly 36 comprises a support 37 adapted to lay over the upper part of the recess 3 1. The support 3 7 carries, about its periphery, a plurality of drive wheels 38. The drive wheels 38, as can be seen

firom- Figure 8, are each radially located. Thus the pivot axis of each drive wheel 8 extends perpendicularly to the radius extending to the recess 3 1. It is to be appreciated that when the support 37 is positioned immediately above the recess 3 1, the drive wheels 38 will engage the upper part of the stretched out air-bag 34. If the drive wheels are caused to rotate so that the lower part of each drive wheel 38 moves inwardly towards the centre of the recess 3 1, the drive wheels will force the fabric of the air-bag 34 into the housing 32 through a slot defined between the support 37 and the housing 32. The upper surface of the table 30, at least adjacent the recess 3 1, may be coated with a low ffiction material, or the upper surface of the table 30 may be provided with rollers or other such elements to facilitate the driving of the air- bag into the housing 32: Indeed in a modified embodiment of the invention the table may be itself provided with driven wheels adapted to form nips with the previously-described drive wheels 38. In any event, it is to be appreciated that the wheels 38 will drive the fabric of the air-bag into the housing 32 through a slot in such a way that the fabric of the air-bag is crumpled or crushed as it is moved into the housing 32. When the fabric of the air-bag has been moved into the housing, an element similar to the element I I may be moved into the position previously occupied by the support 37 in order to apply a final compressing force to the fabric within the air-bag, and procedural steps similar to those described above with reference to Figures 2 to 7 may be followed in order to provide a complete unit comprising the folded air-bag 34 within the housing 32, the housing having an associated cover secured thereto.

Referring now to Figures 9 to 11, a fin-ther embodiment of the invention is illustrated in which, again, drive means are used to drive the fabric of an air-

The cylinder 43 is initially actuated so that the support block 42 is at a radially outward position within the passage 40, and the cylinder 44 is then activated to drive the piston rod 45 carrying the drive-head 46 upwardly so that the teeth 47 provided on the drive-head 46 engage the lower layer of fabric of the air-bag 5. The fabric of the air-bag 5 is trapped between the drive-head 46 and the under-surface of the flange 48. The under-surface of the flange 48 may, if desired, be treated with a low friction material. Subsequently the cylinder 43 is actuated to drive the support block 42 through the passage 40 towards a radially inner position, and the head 46 thus serves to drive the fabric of the air-bag towards the recess 3 containing the housing 4, the fabric of the air-bag passing through a slot defmed between the closure element 11 and the wall of the housing 4 into the housing. This can be seen in Figure 11. The fabric, as it enters the housing, becomes crumpled. Subsequently the cylinder 44 may be act uated to lower the drive-head 46 and the cylinder 43 may be used to return the support block 42 to the initial position. The described cycle of operation may then be completed. However, to drive the air-bag 5 completely into the housing 4, a plurality of said cycles of operation are needed. When all of the fabric of the air-bag is present within the housing 24, the recess closure I I is pressed further downwardly firmly compressing the folded air-bag within the housing 4, and physically driving the housing 4 downwards, within the recess, as in the manner described with reference to Figure 3. A cover may subsequently be mounted on the housing using the techniques as described in Figures 5 and 6.

In the present specification "comprise" means "includes or consists of' and "comprising" means "including or consisting of'.

bag through a slot into a housing, but in this embodiment of the invention the drive means are reciprocating drive means rather than rotary drive means. The apparatus of Figure 9 is similar to that of Figure 1 save that the recess 3 containing the housing 4 is not located above the table 2, but instead is located so that the mouth of the recess is substantially flush with the table 2. A plurality of radially extending passages 40 are provided within the table 2, each passage 40 containing a drive mechanism 41. The drive mechanism 41 comprises a support block 42 which is movable within the passage 40 by means of a piston 43. The support block 42 may thus be moved towards and away from the recess 3. The support block 42 supports a vertical cylinder 44. A piston within the cylinder 44 has a piston rod 45 emerging from the upper part of the cylinder 44, and the rod 45 supports a drive-head 46, the upper surface of which is provided with a plurality of teeth 47. Preferably four or more teeth are provided. Initially the housing 4 is located within the recess 3 with the fabric of the air-bag 5 spread out in a generally flat condition lying on the surface of the table 2, thus over-lying the upper ends of the passages 40. Subsequently, a recess closure element I I is lowered so that the recess closure element substantially closes the upper end of the recess. Simultaneously a flange 48, which surrounds the recess closure element I I is lowered, so that the lower surface of the flange 48 is flush with the lower surface of the closure element 11. The flange 48 overlies the table 2, and in particular overlies the passages 40 provided in the table 2.

As can be seen from Figure 10, the flange 48 serves to trap the fabric of the air-bag against the upper surface of the table 2.

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 fimction, 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. An apparatus for folding an air-bag, the apparatus comprising means adapted to receive and retain a housing to which an air-bag is connected and into which the air-bag is to be folded, and drive means adapted to engage parts of the fabric of the air-bag initially on the exterior of the housing to drive the fabric into the interior of the housing, the apparatus comprising means to substantially close the housing while defining a slot through which part of the air-bag passes, the drive means being adapted to drive the fabric of the air-bag into the housing through the slot.
2. An apparatus according to Claim 1 wherein the drive means surround a recess which constitutes the means to receive and retami the housing.
3. An apparatus according to Claim 2 wherein the drive means support the fabric of the air-bag in a substantially flat state, and engage at least one side of the fabric to drive the fabric into the housing.
4. An apparatus according to any one of the preceding Claims wherein the drive means engage at least a lower layer of fabric to drive the fabric.
5. An apparatus according to any one of the preceding Claims wherein the drive means are rotary drive means.
6. An apparatus according to Claim 5 wherein the rotary drive means comprise a plurality of drive-belts located about the retaining means, the drive-

<Desc/Clms Page number 16>

belts being adapted to support the fabric of the air-bag when initially laid out about the retaining means.
7. An apparatus according to Claim 5 wherein each said drive-belt is associated with a co-operating drive-belt, the co-operating drive-belt being movable between an initial retracted position and a final operative position, the said guide belt, when in the operative position, having a lower portion thereof substantially in engagement with the upper portion of the first said drive-belt.
8. An apparatus according to Claim 5 wherein the retaining means are defined in a central region of a table and the rotaiy drive means comprise a plurality of driven wheels carried on a support, the support being positionable above the retaining means and above the table, so that the rotary drive means engage the fabric of the air-bag.
9. An apparatus according to Claim 8 wherein the table is provided with friction-reducing means to facilitate movement of the air-bag relative to the table.
10. An apparatus according to Claim 9 wherein the friction-reducing means comprise rollers or other rotatably mounted elements provided on the table.
11. An apparatus according to any one of Claims I to 4 wherein the drive means comprise reciprocating elements which engage and drive the fabric on moving towards the housing, and which are disengaged from the fabric on moving away from the housing.
12. An apparatus according to Claim I I wherein the reciprocating elements engage upper and lower sides of the fabric.

<Desc/Clms Page number 17>
13. An apparatus according to any one of the preceding Claims wherein an element is provided adapted to compress the fabric of the air-bag, after it has been driven into the housing by the drive means.
14. An apparatus according to any. one of the preceding Claims wherein means are provided to move the housing into engagement with a cover after the fabric of the air-bag has been inserted into the housing.
15. A method of folding an air-bag into a housing, the method comprising the steps of locating the housing, to which part of the air-bag is connected, in retaining means, and using drive means to drive the fabric of the air-bag into the housing through a slot.
16. A method according to Claim 15 wherein the drive means are rotary drive means which comprise a plurality of co-operating pairs of drive-belts, surrounding the means retaining the housing, the drive-belts initially receiving the fabric of the air-bag.
17. A method according to Claim 15 wherein the drive means are rotary drive means which comprise a plurality of drive wheels on a support adapted to be located above the retaining means.
18. A method according to Claim 15 wherein the drive means are reciprocating drive means.
19. A method according to any one of Claims 15 to 18 including the preliminary step of spreading out the air-bag.

<Desc/Clms Page number 18>
20. A method according to any one of Claims 15 to 19 wherein the method includes the subsequent step of compressing the fabric of the air-bag when it is in the housing.
21. A method according to any one of Claims 15 to 20 wherein the method comprises the subsequent step of securing a cover to the housing.
22. An apparatus for folding an air-bag substantially as herein described with reference to and as shown in Figures I to 6 of the accompanying drawings.
23. An apparatus for folding an air-bag substantially as herein described with reference to and as shown in Figures I to 6 as modified by Figures 7 and 8 of the accompanying drawmigs.
24. An apparatus for folding an air-bag substantially as herein described with reference to and as shown in Figures I to 6 as modified by Figures 9 to 11.
25. A method of folding an air-bag substantially as herein described with reference to the accompanying drawings.
26. Any novel feature or combination of features disclosed herein.