Patent Publication Number: US-2002005635-A1

Title: Inflatable occupant protective cushion

Description:
FIELD OF THE INVENTION  
       [0001] The invention relates to an inflatable occupant protective cushion for use in an upper side area in vehicles beneath a vehicle roof edge, comprising at least one inflatable chamber that has a wavy contour along an edge facing away from the roof edge.  
       BACKGROUND OF THE INVENTION  
       [0002] The height of the inflatable occupant protective cushion for the upper side area in vehicles as is known in the state of the art varies between 400 mm and 430 mm. This size results from the maximum width of the starting material that can be coated in one processing step, which has been 1720 mm until now. Therefore, in order to have as little waste material as possible, preferably four strips having a width of 430 mm were cut from the coated raw material. Today&#39;s coating machinery is also able to coat fabric that is 2000 mm wide in one processing step. This allows protective cushions that have a total height of 500 mm and that consequently ensure better protection for the occupants in case of a collision since a larger surface area of the window is covered. Another reason for the increasing size of protective cushions has to do with new vehicle models such as, for example, vans, which have a much taller structure and thus also require a higher protective cushion. One problem that arises in this context is the larger volume of the protective cushion, for which the current gas generators are no longer adequate.  
       BRIEF SUMMARY OF THE INVENTION  
       [0003] The invention provides an inflatable occupant protective cushion for use in an upper side area in vehicles beneath a vehicle roof edge which, in spite of a possibly greater total height, can still be used in conjunction with the current gas generators.  
       [0004] This is achieved by an inflatable occupant protective cushion for use in an upper side area in vehicles beneath a vehicle roof edge having at least one inflatable chamber with a wavy contour along an edge facing away from the roof edge, said chamber when inflated having a volume not exceeding 30 liters. The volume reduction results from the wavy contour defining a height between a wave crest and a wave trough that amounts to at least 50 mm and having a number of waves that is less than 10.  
       [0005] Especially when an occupant protective cushion is unfolded, the fabric is subjected to extreme stress, whereby the stress in the area of the circumferential edge can be especially high. In order to reduce the force peaks on the edge and to distribute them over the entire fabric, the edge that is adjacent to the inside of the inflatable chamber is wave-shaped. With the inflatable occupant protective cushions available so far, the wave height of the wavy contour was only a few millimeters. With the present invention, the wave height, amounting to at least  50  mm, means that, for one thing, the stress on the edge is diminished, and secondly that the volume of the protective cushion is reduced.  
       [0006] According to a particular embodiment, the chamber consists of two textile materials that are coated inside of the chamber and joined to each other along a peripheral edge.  
       [0007] Here, it is especially advantageous for the textile material parts to be cut from a coated strip of textile material having a width of about 2000 mm, and for the cushion having a total height from the roof edge to an edge facing away from the roof edge that amounts to about 500 mm. The greater total height has the advantage that a larger part of the vehicle window is covered by the inflated protective cushion and thus that the risk of injury to the vehicle occupant is reduced in case of a collision.  
       [0008] According to another advantageous embodiment, the total height of the cushion from the roof edge to an edge facing away from it amounts to more than 500 mm. In this manner, it is also possible to ensure sufficient protection in case of a collision, even those involving vehicles with a taller vehicle structure and thus a larger window surface area. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009] Further advantages and features of the invention become apparent from the following description of a preferred embodiment as evident from the single drawing to which reference is made and in which:  
     [0010]FIG. 1 shows a completely unfolded occupant protective cushion. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0011] The drawing shows a completely unfolded occupant protective cushion for the upper side area that extends, for example, from next to the front occupant to next to the rear occupant.  
     [0012] The inflated occupant protective cushion  10  shown in FIG. 1 for the upper side area consists of two opposite walls  12 ,  14 , which are each made of a textile material part  16 ,  18 , of which only the front wall  12  made of the textile material part  16  can be seen, and which form an inflatable chamber  20 . The inflatable chamber  20  is divided into several partial chambers  22  which are flow-connected with each other and separated from each other by several partitions  24  formed by sector-wise connection of the two opposite walls  12 ,  14 . A gas lance (not shown here) can be inserted through an opening  28  between an upper circumferential edge  26 , which is adapted to the course of the roof frame, and the upper areas of the separating partitions  24 , which are essentially parallel to the roof frame. The two textile material parts  16 ,  18  are coated on their inside and joined to each other at their circumferential edge  30 . This connection can be sewn or woven. The edge  30  of the inflatable chamber, which is located across from the roof edge, has a wavy contour  32 . The wave height H results from the distance between one wave crest and its adjacent wave valley, and it is at least  50  mm. The number of edge waves here is six.  
     [0013] When a protective cushion is inflated, the textile material parts of the protective cushion are subjected to extra stresses in the area of the lower edge. Due to the wave-shaped contour of the edge, the warp and weft yarns of the textile material parts, which are shown with reference to a yarn  34  and  36  as an example, are subjected to lower stresses than if the edge  32  were to run, for example, parallel to a warp yarn  34 . In the latter case, the warp yarn  34  would not be able to absorb any tensile stress and the entire tensile stress would have to be absorbed by the weft yarn  36 . The wavy contour in question here has wave heights H which amount to at least 50 mm. As a result, in addition to achieving the stress relief, the volume of the inflatable chamber  20  is also reduced while the total height of the protective cushion  10  remains the same. Consequently, with protective cushions whose total height is more than the current standard height of between 400 mm and 430 mm, it is achieved that their volume does not exceed 30 liters and that they can readily be used with the existing gas generators that are suitable for protective cushions up to a volume of 30 liters.  
     [0014] With the embodiment shown here, the total height of the protective cushion  10  from the roof edge to the side facing away from the roof edge should be about 500 mm. Moreover, due to the wavy contour, conventional gas generators can be used and the greater total height ensures a better protection for the vehicle occupants in case of deployment. Furthermore, this greatly reduces the risk of injury to arms and legs in the lower side area as a result of window surface that is not covered by the protective cushion  10 .  
     [0015] The wavy contour  32  of the embodiment shown here is irregular, but according to the invention, a regular wavy pattern would also be possible. Due to the irregular wavy pattern, it is possible to adapt the shape and the inflation behavior of the protective cushion to the vehicle geometry and to the position of the vehicle occupants.  
     [0016] According to an improvement of the invention not shown here, the total height of the protective cushion is more than 500 mm. Protective cushions with such total heights have the advantage that they can be used in vehicles with large window surfaces, for example, vans. The structure and the functioning of such a protective cushion essentially match the embodiment shown in FIG. 1, although the division of the inflatable chamber into partial chambers can be configured somewhat differently.  
     [0017] In case of deployment, gas is fed into the protective cushion  10  via the gas lance (not shown here). The gas flows through outflow openings into the chambers  22  and causes a rapid unfolding of the protective cushion  10  in the downward direction. The protective cushion  10  positions itself firmly in the vehicle at the side of the heads of the front and rear passengers and in front of the side windows, thus protecting the vehicle occupants from injuries.