WO2003059703A1

WO2003059703A1 - A steering wheel arrangement

Info

Publication number: WO2003059703A1
Application number: PCT/SE2002/002441
Authority: WO
Inventors: Mats ÅHMAN
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2002-01-16
Filing date: 2002-12-23
Publication date: 2003-07-24
Anticipated expiration: 2004-07-16
Also published as: GB2384211A; AU2002359215A1; GB0200952D0

Abstract

The steering wheel arrangement has a steering wheel which includes a frame defining a rim to be connected to the steering column. An air-bag cover (7) is mounted on the steering wheel. The cover (7) and the steering wheel have cooperating retaining formations (33), (35), in the form of a recess (35) in a retaining element (9) in the steering wheel, and a projection (33) on the cover (7). The cover (7) is resiliently biased (30) to urge the projection element (33) into engagement with part of the recess (9). The cover (7) is movable against the spring bias with a floating movement.

Description

"A STEERING WHEEL ARRANGEMENT"

THE PRESENT INVENTION relates to a steering wheel arrangement, and more particularly relates to a steering wheel arrangement for use in a motor vehicle such as a motor car.

It has been proposed previously to provide an air-bag unit mounted on a steering wheel, with the air-bag unit comprising a housing containing an air-bag and an inflator adapted to inflate the air-bag in the event that an accident should occur. The air-bag is configured to be located in front of the driver of a vehicle when the air-bag is inflated to provide a cushioning or protective effect.

It has been proposed previously (see, for example, GB-A-2,309,123) to mount the entire housing containing the air-bag and the gas generator movably on the steering wheel at a central position, so that the entire housing may be moved manually relative to the steering wheel to effect operation of a horn. This, means that a relatively large mass has to be moved in order to activate the horn, which is undesirable.

The present invention seeks to provide an improved steering wheel arrangement. According to one aspect of this invention there is provided a steering wheel arrangement, the arrangement comprising a steering wheel having a rim and a frame which is adapted to be connected to a steering column, there being an air-bag cover mounted on the steering wheel, the cover and the steering wheel having co-operating retaining formations, in the form of at least one triangular recess and at least one projecting element received within the recess, the cover being resiliently biased to urge the or each projecting element into engagement with part of the recess in which it is received to retain the cover in position, the cover being moveable against the bias with a floating movement.

Preferably there are a plurality of recesses and a plurality of projecting elements, each projecting element being received within a respective recess.

Advantageously the projecting elements are present on the cover and the said recesses are present in retaining elements mounted on the steering wheel.

Conveniently the retaining elements are two-part elements each with a split-line passing through each recess.

Preferably contact elements are provided which, on movement of the cover, complete a horn circuit.

Conveniently an air-bag is retained in position beneath the cover, the cover being rupturable in response to inflation of the air-bag.

Preferably the cover is provided with first restricting elements which extend from an inner surface of the cover and which are engaged by cooperating second restricting elements mounted on the steering wheel. Conveniently the said first restricting elements are provided with elongate apertures, the second restricting elements being hooks provided on the steering wheel which engage with said apertures.

According to another aspect of this invention there is provided a steering wheel arrangement, the arrangement comprising a steering wheel having a frame adapted to be fixed to a steering column and a rim, the frame supporting a gas generator associated with an air-bag, there being a rupturable cover for the air-bag, the cover being movable relative to the frame of the steering wheel to bring electrical contact elements carried by the wheel and the cover into contact with each other, the cover being associated with resilient elements resiliently biasing the cover upwardly away from the gas generator, there being at least one retaining element on the steering wheel located adjacent the periphery of the cover, the retaining element and the cover being provided with at least one set of co-operating retaining formations, one of the or each set of formations comprising a triangular recess and the other of the or each set of formations comprising a projection extending into the recess.

Preferably there are a plurality of sets of co-operating formations, each formation comprising a recess and a projection extending into the recess.

Conveniently each recess is in a retaining element on the steering wheel, and each projection is on the cover.

Advantageously each recess has an upwardly directed apex, and each projection is a projecting element which extends substantially in a plane which receives the cover of the air-bag. Conveniently the or each retaining element is formed of two components which are fastened together, having a split-line passing through each recess in the retaining element.

Preferably the frame is provided with two upstanding arms at spaced- apart positions, each arm carrying, at its upper end, an electrical contact, the cover having electrical contacts co-aligned with the contacts provided on the arms of the frame.

Conveniently the resilient elements are helical compression springs which surround the contacts provided on the frame and the contacts provided on the cover, the springs serving to bias the cover away from the gas generator.

Advantageously the cover is provided with depending restricting elements which extend down towards a lower part of the steering wheel frame, the depending restricting elements being apertured and engaging hooks which extend upwardly from the lower part of the steering wheel.

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 plan view of a steering wheel in accordance with the invention,

FIGURE 2 is a sectional view taken on the line II-II of Figure 1,

FIGURE 3 is a sectional view taken on the line III-III of Figure 2, FIGURE 4 is an enlarged view of part of the embodiment of Figures 1 to 3, and

FIGURE 5 is a view corresponding to Figure 1 illustrating an alternative embodiment of the invention.

In the embodiments of the invention a steering wheel arrangement is provided in which an air-bag is mounted within a chamber partly defined by a "floating" or movable top cover. The top cover of the chamber may be depressed against a spring bias in order to actuate a horn. Thus the mass of the component that has to be moved to operate the horn or hooter is significantly less than the mass that has to be moved in the prior art arrangement discussed above.

Referring initially to Figure 1 of the accompanying drawings, a steering wheel 1 is provided which has an outer rim 2. The outer rim is provided with a plurality of spokes 3, 4, 5, which extend substantially radially inwardly from the rim towards a central part of the steering wheel.

The precise design or configuration of the spokes shown in the accompanying drawings is given by way of example, and many alternative designs may be utilised.

Located towards the centre of the steering wheel is an air-bag unit 6 which, as will become clear from the following description, has a movable upper cover 7.

Mounted on the steering wheel, associated with the spokes 3, 4 and 5 are two elongate retainer elements 8, 9, which retain the cover in position. The way in which the retainer elements function will become clear from the following description. The elongate elements 8, 9, each extend from a point on the rim 2 adjacent the base of the spoke 5, and past the side of the air-bag unit 6, continuing, overlying part of the spoke 3 or 4 respectively to a further point on the rim 2 adjacent the end of the spoke 3 or 4.

Referring now to Figures 2 and 3 of the accompanying drawings, the steering wheel of Figure 1 incorporates a support frame 10. The support frame 10 is adapted to be mounted securely in position on the steering column of a motor vehicle by a fixing arrangement which is not illustrated. The support frame 10 includes a generally planar base 11. At two opposite sides, the base 11 is provided with upwardly directed support plates or arms 12, 13. The upper end of each support plate or arm is provided with at least one upwardly directed cylindrical projection 14, 15. The base 11, the support plates or arms 12, 13, and the projections 14, 15 are all made of metal.

An aperture is provided in the centre of the base 11 which receives, in a conventional manner, a gas generator or inflator 16. The gas generator or inflator 16 is provided to inject gas into an air-bag 17 which is initially tightly folded and lies immediately above the gas generator 16. The air-bag 17 may be held in the folded state by a rupturable cover or breakable straps.

In the described embodiment four upwardly extending hook elements are provided which each extend upwardly from the base 11. Two spaced-apart identical hook elements 18 lie adjacent the plate 12, and two spaced-apart identical hook elements 19 lie adjacent the plate 13. Each hook element terminates with an outwardly directed horizontal arm 20, 21. The horizontal arms 20, 21 are located above the base 11, and terminate adjacent the respective plates 12 and 13. The cover 7 is provided with a generally planar upper region 22 which may be provided with one or more lines of mechanical weakness 23, to facilitate the rupturing of the cover on inflation of the air-bag 17 so that the air- bag 17 may be deployed in an appropriate manner. The cover is provided, on its under-surface, with two depending elements 24, 25. Each element is provided with two elongate apertures 26, 27 therein. The axis of each aperture is perpendicular to the plane of the planar upper region of the cover. The apertures 26 receive the free ends of the horizontally extending arms 20, and the elongate apertures 27 receive the free ends of the horizontally extending arms 21. In a modified embodiment, each depending element is replaced by two spaced-apart depending legs, each leg having an elongate aperture therein.

On the under-surface of the planar upper region 22 of the cover 7 are depending metallic cylindrical contacts 28, 29 which are in alignment with the cylindrical projections 14 and 15 provided on the upstanding support plates or arms 12 and 13. Helical compression springs 30, 31 are provided which surround the co-aligned projections and contacts, the compression springs 30, 31 serving to bias the cover 7 upwardly away from the base 11.

The cover is provided with at least two outwardly extending projections 32, 33, which may be in the form of integrally formed pins which extend outwardly beyond the periphery of the planar upper region 22 of the cover 7 within the plane of that planar upper region 22.

The projections 32 and 33 are received within recesses 34, 35 that are formed within the retaining elements 8 and 9. Each recess is of generally triangular form with an apex at the upper part of the recess. Each retaining element, as shown in Figure 2, may be formed of a two-part form, the two parts being snapped together or otherwise interconnected to form the complete retaining element, with the split-line between the two parts intersecting the recesses 34, 35.

In assembling the steering wheel arrangement described above, the gas generator and the associated air-bag will initially be mounted in position on the base 11 of the frame 10. Subsequently the cover 7 will be mounted in position, and the depending elements 24, 25 of the cover and the upstanding hooks 18, 19 provided on the base, will be so manipulated that the horizontally extending arms 20, 21 are received within the respective apertures 26 and 27. For example, the hook elements 18, 19 may have a snap-action function. The springs 30 and 31 will be trapped in position during this procedure. The projections 32 and 33 will be received and retained within the recesses 34, 35, possibly by snapping on the upper part of the retaining elements 8 and 9 after the cover 7 has been initially located in position. The springs 30, 31 will bias each projection 32, 33 into engagement with the upper apex of the respective recess 34, 35.

When the steering wheel assembly has been assembled as described, it will be appreciated that the cover 7 may be moved upwardly and downwardly by the application of pressure to the upper region 22 of the cover. As the cover moves downwardly, the depending elements 24 and 25 will move slightly, but this movement is permitted by virtue of the fact that the horizontally extending arms 20, 21 of the hook elements 18, 19 are located within elongate apertures 26, 27 which have an appropriate vertical extent. As the cover 7 is moved downwardly, so electrical contact may be established between the contacts 28 and 29, and the upstanding cylindrical projections 14 and 15, thus completing a horn circuit. The cover 7 is thus a "floating" button which, when depressed, actuates a horn. The cover 7 is prevented from becoming disconnected from the steering wheel under the bias of the springs 30, 31 and is thus retained by the engagement of the projections 32 and 33 within the triangular recesses 34, 35. Thus, the projections and recesses constitute cooperating retaining formations. Because the recesses are triangular, if the cover 7 is depressed, thus compressing the compression springs 30 and 31, the cover 7 will have a certain degree of freedom of movement which provides the cover with a desirable feel.

If the cover is released, the nature of the triangular recesses is such that the projections 32, 33 will each be guided to the upper apex of the appropriate recess, and thus the cover 7 will return to the desired position.

In the event that the air-bag should inflate, the cover or straps retaining the air-bag will rupture or break, and the horizontal part of the cover will rupture, along the lines of mechanical weakness 23, to form separate parts that open like doors to permit the air-bag to escape. The cover parts will not be discharged from the central part of the steering wheel, because the cover parts will be retained by virtue of the engagement of the hook elements 18 and 19, with the apertures 26, 27 formed in the depending elements 24, 25, provided on the cover 7. The depending elements 24, 25 and the hook elements 18, 19, thus act as co-operating restricting elements which restrict movement of the cover parts away from the steering wheel, and which prevent the cover parts from becoming separated from the steering wheel.

It is to be appreciated that there will be at least two projections 32, 33 on opposed sides of the cover to ensure that the cover returns to a desired position, and in a preferred embodiment there may be a greater number of projections, each co-operating with an appropriately dimensioned and located recess. In a modified embodiment of the invention, projecting pins may be provided on the retaining elements, with those projecting pins being received within recesses formed on the periphery of the cover. The recesses in such an embodiment may again be of triangular form, but each having a downwardly directed apex.

Figure 5 is a view corresponding to Figure 1 illustrating an alternative form of retaining element where the retaining elements 36, 37 are of annular form. As well as having a part that lies adjacent the spoke 4 and which passes by the side of the air-bag unit 6, each element covers a respective spoke 3 or 4. Each element has a portion which extends, from the base of the spoke 3 or 4, adjacent the interior of the rim, back to the base of the spoke 5.

In the present Specification "comprises" means "includes or consists of and "comprising" means "including or consisting of.

Claims

CLAIMS:

1. A steering wheel arrangement, the arrangement comprising a steering wheel having a rim and a frame which is adapted to be connected to a steering column, there being an air-bag cover mounted on the steering wheel, the cover and the steering wheel having co-operating retaining formations, in the form of at least one triangular recess and at least one projecting element received within the recess, the cover being resiliently biased to urge the or each projecting element into engagement with part of the recess in which it is received to retain the cover in position, the cover being moveable against the bias with a floating movement.

2. An arrangement according to Claim 1 wherein there are a plurality of recesses and a plurality of projecting elements, each projecting element being received within a respective recess.

3. An arrangement according to Claim 2 wherein the projecting elements are present on the cover and the said recesses are present in retaining elements mounted on the steering wheel.

4. An arrangement according to Claim 3 wherein the retaining elements are two-part elements each with a split-line passing through each recess.

5. An arrangement according to any one of the preceding Claims wherein contact elements are provided which, on movement of the cover, complete a horn circuit.

6. An arrangement according to any one of the preceding Claims wherein an air-bag is retained in position beneath the cover, the cover being rupturable in response to inflation of the air-bag.

7. An arrangement according to Claim 6 wherein the cover is provided with first restricting elements which extend from an inner surface of the cover and which are engaged by co-operating second restricting elements mounted on the steering wheel.

8. An arrangement according to Claim 7 wherein the said first restricting elements are provided with elongate apertures, the second restricting elements being hooks provided on the steering wheel which engage with said apertures.

9. A steering wheel arrangement, the arrangement comprising a steering wheel having a frame adapted to be fixed to a steering column and a rim, the frame supporting a gas generator associated with an air-bag, there being a rupturable cover for the air-bag, the cover being movable relative to the frame of the steering wheel to bring electrical contact elements carried by the wheel and the cover into contact with each other, the cover being associated with resilient elements resiliently biasing the cover upwardly away from the gas generator, there being at least one retaining element on the steering wheel located adjacent the periphery of the cover, the retaining element and the cover being provided with at least one set of co-operating retaining formations, one of the or each set of formations comprising a triangular recess and the other of the or each set of formations comprising a projection extending into the recess.

10. A steering wheel arrangement according to Claim 9 wherein there are a plurality of sets of co-operating formations, each formation comprising a recess and a projection extending into the recess.

11. An arrangement according to Claim 10 wherein each recess is in a retaining element on the steering wheel, and each projection is on the cover.

12. An arrangement according to Claim 11 wherein each recess has an upwardly directed apex, and each projection is a projecting element which extends substantially in a plane which receives the cover of the air-bag.

13. An arrangement according to Claim 11 or 12 wherein the or each retaining element is formed of two components which are fastened together, having a split-line passing through each recess in the retaining element.

14. An arrangement according to any one of Claims 9 to 13 wherein the frame is provided with two upstanding arms at spaced-apart positions, each arm carrying, at its upper end, an electrical contact, the cover having electrical contacts co-aligned with the contacts provided on the arms of the frame.

15. An arrangement according to Claim 14 wherein the resilient elements are helical compression springs which surround the contacts provided on the frame and the contacts provided on the cover, the springs serving to bias the cover away from the gas generator.

16. An arrangement according to any one of Claims 9 to 15 wherein the cover is provided with depending restricting elements which extend down towards a lower part of the steering wheel frame, the depending restricting elements being apertured and engaging hooks which extend upwardly from the lower part of the steering wheel frame.