FASTENER FOR AIR-BAG CURTAIN

TECHNICAL FIELD

The invention relates to a fastener for fixing a curtain airbag to a body panel in a vehicle.

BACKGROUND ART

In vehicles, such as personal cars, it is common practice today to include an airbag curtain. These airbag curtains may for example be attached at the inside of the vehicle at the side panels near the roof. In case of an accident, the curtains are adapted to be activated and thus form a safe guard against hitting the hard parts of the vehicle. In case of a curtain located at the side, its main purpose is to protect the driver or the occupants, in particular in the event of a side impact, from hitting the side panels and the side windows.

When the curtains are activated, there is large force acting on the fastener of the curtain and the panel to which it is attached. In order to be able to securely fasten the curtain to the vehicle, or the vehicle panels, it is needed to make the fastener enough robust to withstand the forces developed at activation of the curtain.

In EP 1 422 112, it is described a fastener for an airbag curtain. According to this fastening system, the airbag is provided with an anchor portion which is attached to a side panel of the car by means of fasteners. Each fastener squeezes the anchor portion between the panel and a flange of the fastener when the curtain is attached to the panel. The fastener is securely attached by means of a tapping screw driven into a shank when the fastener is inserted in a mounting hole.

There are further solutions of fastening an airbag curtain to a panel described in for example EP 1 522 466, EP 1 502 824 and GB 2 364 975 which describes related art to which the present invention is directed.

Even though the above mentioned documents describe different systems that works today there are still further developments which are desired to improve the present fasteners and the present system. The fastener according to the present invention aims to provide a fastener which is easy to mount and easy to manufacture while providing low material and manufacturing costs. There is also a need for providing a feature for controlling that the fastener is readily attached to the mounting hole. Hence, there is still a need for an improved fastener which take into account the easiness of manufacturing the fastener and to provide a fastener which is easy to mount and take into account further different desires in the mounting process of the airbag curtain, e.g. a built in function which makes it easier to know that the fastener is securely attached.

DISCLOSURE OF INVENTION

In one aspect of the invention, the present fasteners are easy to manufacture at a low cost while also providing easiness concerning mountability while providing a reliable fastening of an airbag curtain to a body panel of a car.

The fastener according to the present invention is primarily intended for fastening an airbag curtain to a vehicle. This is achieved by fixing the fastener to a mounting hole in a body frame or the like of the vehicle. The fastener comprises a clip and a support element. In a specific embodiment the fastener only consists of these two elements even though it is possible to include further parts. The clip may be shaped from a metal sheet material and the support element may be made by moulding some plastic or composite material. The clip comprises an insertion part, provided with at least one locking shank, intended to be inserted into said mounting hole, an indentation region intended to be in contact with the edge part of the

mounting holes when the clip is positioned in its fastening position and a clamping portion intended to press the airbag-anchor portions against the body frame of the vehicle. The support element comprises one or several wedge shaped surfaces and is adapted to fit into the clip in such a way that the clip is widened while the support element is pushed into the clip. The fastener is further designed in such a way that said support element comprises a shoulder adapted to engage with the at least one locking shank when the support element is inserted into the clip such a distance that the fastener is in its locking position, e.g. when the fastener is positioned in the mounting hole and the support element is inserted into the clip enough to provide a secure attachment to the vehicle.

Hence, such a fastener is described in claim 1. The fastener is easy to mount since it is adapted to fit in the mounting hole by introducing a part of the fastener into the hole by hand without the use of a screwdriver or any other tool. This is made possible due to a wedge shaped support element, forming part of the fastener, which is adapted to be pushed into a mounting hole while spreading shanks of a clip. The support element will be maintained in its locking position by a snap-in fitting which secures the clip of the fastener in a fixing position.

According to one embodiment of the invention, the wedge shaped supporting element is inclined, or being widening, along essentially its whole length until the contact point with the clip has reached the position where it is secured by the snap-in, locking arrangement. By being arranged in such a way, there is a force acting in the direction opposite to the direction in which the wedge shaped element is pushed during the mounting of the fastener, all the way until the support element has reached its locking position and is secured in that position by the snap-in fitting. The wedge shaped support element may of course be designed in such a way that it will still be inclined, or widening, also when the wedge shaped element is in its locking position. The benefit of such an arrangement is that if the support element not is introduced to its

locking position, the force working on the wedge shaped element will push the wedge shaped element back and out again. In this way it can easily be detected that the fastener is not readily and securely attached to the mounting hole. Still another advantage is if there is a desire to dismount the airbag curtain. Due to the force acting to push out the support element, the dismounting may be easily done if the shanks providing the snap-in locking arrangement are disengaged. Hence, no or very little pulling force is needed to pull out the fastener from the mounting hole. Still further advantages may be found in the examples of the invention which follows.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 An airbag curtain mounted in a car

Fig. 2 An isometric view of a fastener

Fig. 3 An isometric view of a clip forming part of the fastener

Fig. 4 An isometric view of a wedge shaped support element forming part of the fastener.

Fig. 5 An cross sectional view along the longitudinal axis of the fastener in fig. 2

Fig. 6 An cross sectional view along the longitudinal axis of the fastener in fig. 2 when positioned in a mounting hole

Fig. 7 a-e A cross sectional view along the longitudinal axis illustrating 5 stages of the mounting of the fastener into a mounting hole.

Fig. 8 A cross sectional view along the longitudinal axis illustrating the fastener when mounted in a mounting hole.

EMBODIMENT(S) OF THE INVENTION

In fig. 1 , it is exemplified how a curtain airbag 1 , comprising a main body portion 2 and airbag-anchor portions 3, may be mounted to a car 4. The curtain airbag 1 is intended to protect an occupant of the car 4, and is attached to an interior member, such as a body frame 5, of a car 4 on the upper side of front and rear door windows 6. In a collision, the airbag 2 is activated to suddenly expand, i.e. rapidly deploy, downward along the door windows 6 in response to gas spouting from a compressed gas source, so- called inflator 7, so as to protect the head and body of the occupant. The airbag-anchor portions 3 are fixed to a body panel of an automobile, such as the body frame 5, at a plurality of preformed mounting holes 8 located at the positions of the airbag anchor portions 3 above the windows 6. The main airbag body 2 is normally folded in a compact size and disposed at a fixed position above the door windows 6.

In fig. 2, an isometric view of a fastener 9 for fastening of an airbag curtain to a car is shown. The fastener 9 comprises a clip 10 intended to be inserted into a mounting hole, and a wedge shaped, distance maintaining support element 11.

Fig. 3 shows an isometric view of the clip 10. The clip may be defined to comprise three different regions or portions. A first portion comprises a wedge shaped, resilient part called the insertion part 12 which is intended to be inserted through a mounting hole (see reference number 8, fig 1). A second portion is called a groove or an indentation region 13 which is the portion forming a groove in the clip 10 intended to be in contact with the edge part of the mounting holes when the clip 10 is positioned in its fastening position, e.g. when the clip is attaching an airbag curtain to a car as shown in fig. 1. A third portion is called a clamp or a clamping portion 14 which is the part of the clip 10 which is intended to press the airbag-anchor portions (see ref. nr. 3, fig 1) against a body frame (see ref. nr. 5 fig 1) of a car.

The clip may for example be made of sheet metal which is cut, bent and shaped to the desired form. Metal is a desired material for the clip since it is

easily found a relatively thin material which easily can be worked to the desired shape having the desired properties concerning resiliency, bend ability and stiffness. As can be seen in fig. 3, the insertion part 12 comprises two outer shanks 15 a, b being bent to form an arc shaped contour forming the resilient part of the clip 10. The outer shanks 15 are held together by a cross bar 16 in order to provide constructional stability to the insertion part 12. The insertion part 12 further comprises two central locking shanks 17 a, b which purpose is to lock the fastener in its locking position when attaching an airbag curtain to a car.

Fig. 4 shows an isometric view of the wedge shaped, distance maintaining support element 11. The purpose of the support element 11 is to secure the widening and spacing apart of the shanks 15 of the clip 10 so as to provide secure attachment of the fastener 9. The support element comprises two outer side panels 18 a, b which serve to align the clip in the right position. The support element further comprises a pair of wedge shaped rails 19 a,b which serves as widening and distance elements for the clip. The support element also comprises a cross bar 20 which serves a shoulder 21 in order to be locked by the locking shanks of the clip so as to provide support for the clip when the fastener is in its locking position.

It is obvious to the skilled person in the art that the rails may be of different shapes or width and the wedge shaped contour may be formed from any kind of wedge shaped surface.

Fig. 5 is a cross sectional view of the fastener 9 shown in figure 2. The fastener 9 is here shown in its original state before it is inserted into a mounting hole. In this view it is easier too see the shoulder 21 which is formed by the cross bar 20. The shoulder 21 is located at such a location on the support element 11 that the support element 11 is almost fully inserted into the clip 10 and spreading the outer shanks 15 of the clip before the locking shanks 17 engage in their locking position.

Fig. 6 shows the same cross sectional view of the fastener 9 when it is inserted into a mounting hole. In this figure the fastener has only been positioned in the hole but yet not fully inserted to be in its fixing position. As can be seen in this figure, there is space between the body frame 5 and the clamping portion 14 where it is intended that the airbag-anchor portions (not shown) shall be located.

Fig. 7 a-e shows a cross sectional view of a fastener 9 and how it is inserted into its locking position. Fig. 7a shows a cross sectional view of the fastener 9 in its original state before the support element 11 has started to be inserted into the clip 10.

In fig 7b, the support element 11 has moved to the left in the figure and the clip 10 has started to spread by being guided by the wedge shaped rails 19 a,b.

In fig. 7c, the support element 11 has moved further to the left and the clip 10 has widened further. It can also be noted that the locking shank 17 now is supported by the cross bar 20 of the support element 11.

In fig 7d, the support element 11 has moved still a little bit further to the left. The locking shank 17 is now resting on the edge of the shoulder 21 and there is only needed just a little movement further to the left of the support element 11 before the locking shank 17 will be positioned in its locking position. In this figure it can also be noted that the rails 19 are inclined all the way up to the end part 22 of the support element. Hence, this constructional detail will thus provide a force from the clip 10 to move the support element 11 in the opposite direction (to the right) and will function as an additional feature for detecting when the fastener 9 is positioned in its fixing position. If the support element is stopped in this position it will be automatically pressed in an outwards direction and it can be easily detected that the fastener not is fixed properly in the mounting hole.

In fig 7e, the support element 11 is positioned in an engaging relation with the clip 10 in such a way that the fastener 9 is in its locking position. The locking shank 17 is now fixed against the shoulder 21 and thereby preventing an outwards movement of the support element 11.

In fig. 8, the same position of the fastener 9 as shown in fig. 7e is shown but with the additional feature of having a part of the body panel 5 incorporated. From this view it can be seen that the indentation region 13 is located at the location of the mounting hole 8. The support element 11 thus presses the indention region 13 to be in contact with the edges of the mounting hole 8. The support element is kept in place by the locking shank 17 and prevents the fastener 9 from losing its position.