Patent Publication Number: US-2006006630-A1

Title: Gas bag module

Description:
FIELD OF THE INVENTION  
      The present invention relates to a gas bag module.  
     BACKGROUND OF THE INVENTION  
      With some types of gas generators, the electric pulse for activating the igniter is transmitted by a plug that is placed directly onto the protruding connection pins of an igniter arranged inside the gas generator. In such a case, therefore, the plug is in the immediate vicinity of the gas generator. The plug is connected via a cable to a voltage source. If the gas generator is accommodated in a module housing, then the cable extends from the module housing. With such gas bag modules, the plug must remain connected to the gas generator in spite of the impulse generated by the out-flowing hot gases when said gas generator is actuated. Moreover, an optional module housing of the gas bag module has to be sealed in the vicinity of the emerging cable.  
     BRIEF SUMMARY OF THE INVENTION  
      It is an object of the present invention to ensure in a simple manner that the plug cannot detached itself from the gas generator.  
      This is achieved in a gas bag module comprising a gas bag and a gas generator connected to a plug in that the gas bag has a securing flap that holds the plug affixed to the gas generator. Since the securing flap is part of the gas bag itself, no additional components have to be provided or attached. The securing flap merely has to be arranged in such a suitable manner relative to the plug that the plug cannot detach itself from the igniter pins. The plug protection is not only active during the ignition of the gas generator but it also prevents the plug from being shaken loose by vehicle vibrations. Furthermore, the securing flap can also have a sealing effect, especially if the gas generator is accommodated in a module housing.  
      Preferably, the securing flap is in direct contact with the plug and encloses it.  
      The securing flap can be made simply and inexpensively in that it is sewed to the gas bag. It can also be formed by at least one projection of a protection layer arranged on the gas bag. The protection layer is usually formed by an additional piece of fabric, as a rule from gas bag fabric, arranged inside the gas bag. In a simple manner, additional flaps can be provided on the protection layer or layers, optionally integral therewith, said flaps later forming the securing flap.  
      Preferably, the securing flap is in the form of a strip and projects away from the rest of the gas bag. Thus, it can be wrapped around the plug in such a way as to enclose it and firmly affix it to the gas generator.  
      A free end of the securing flap is preferably used in order to attach the securing flap to a generator mount.  
      If the gas bag module has a module housing, the free end of the securing flap is preferably attached to the module housing. Here, e.g., the attachment point of the generator mount suggests itself as a convenient attachment point. In any case, the securing flap is advantageously attached to an element of the gas bag module that is configured so as to be load-bearing, for instance, the generator mount or a section of the module housing that offers an attachment point for the generator mount. Thus, forces acting on the plug, particularly during the actuation of the gas generator, can be absorbed without the free end of the securing flap yielding.  
      The gas generator can be accommodated, at least for the most part, inside the gas bag. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1   a  shows a schematic view of a gas bag module according to the invention before the fixing of the securing flap;  
       FIG. 2   a  shows a schematic view of the gas bag module according to  FIG. 1 , after the fixing of the securing flap;  
       FIG. 3  shows the gas bag module according to  FIG. 2  in a side view;  
       FIG. 4  shows the gas bag module according to  FIGS. 2 and 3 , placed inside a module housing;  
       FIG. 5  shows a flat unfolded gas bag of a gas bag module according to the invention;  
       FIG. 6  shows a section of a cut-out for a gas bag of a gas bag module according to the invention; and  
       FIGS. 7   a  and  7   b  show protection layers for use in a gas bag of a gas bag module according to the invention. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT  
       FIG. 1  shows a gas bag module  10  with a folded gas bag  12  and a gas generator  14  in form of an elongated tubular gas generator.  
      The gas bag module  10  can be used in a vehicle occupant protection system and can, e.g., be mounted in the area of a vehicle seat armrest or a vehicle door.  
      In the gas bag  12  a pocket  19  is formed in which most of the gas generator  14  is accommodated lengthwise (see  FIG. 5 ). At one axial end of the gas generator  14 , there is a pyrotechnical igniter (not shown here) onto whose connection pins (not shown) a plug  20  has been placed. The plug  20  is connected to a voltage source (not shown) and, for example, to a control unit (likewise not shown) via a cable  22 . Another cable, which ends in a tab  24 , serves to ground the gas bag module  10 .  
      The gas generator  14  is enclosed by a clamp-like generator mount  16  that has two attachment tabs  18  facing away from the folded gas bag  12 .  
      The gas bag  12  has a strip-like securing flap  26  that has an attachment slit  30  in the vicinity of its free end  28 . The securing flap  26  serves to affix the plug  20  onto the gas generator  14 . This is shown in  FIGS. 2 and 3 . Here, the securing flap  26  is wrapped around the plug  20  in such a way that it lies tightly against the plug. The attachment slit  30  is pulled over one of the attachment tabs  18  of the generator mount  16 , that is to say, the attachment tab  18  protrudes through the attachment slit  30 . The securing flap  26  lies tightly and under tension against the plug  20  and the attachment tab  18 . As a result, the plug  20  cannot detach itself from the connection pin of the igniter and thus from the gas generator  14 . Consequently, the electric connection between the gas generator  14  and the plug  20  is always ensured.  
      The wrapping of the plug  20  and the further course of the securing flap  26  over the gas bag module  10  is such that the securing flap  26  is not creased but always lies flat against a component.  
       FIG. 4  shows the gas bag module according to  FIGS. 2 and 3  inserted into a module housing  32 . The generator mount  16  is firmly connected to the module housing  32  via the attachment tabs  18  by means of screws  34 . Through this screwed connection, the free end  28  of the securing flap  26  is connected to the module housing  32 .  
      When the module housing  32  is closed, the attachment points for the attachment tabs  18  of the generator mount  16  lie inside said module housing  32  and are protected by it.  
      To ground the gas generator  14 , the tab  24  is connected to the module attachment point via the attachment tab  18  of the generator mount  16  and from there via one of the screws  34  to an electrically conductive vehicle component.  
      The securing flap  26  is arranged in the module housing  32  in such a way that it seals the opening in the module housing  32  that is provided for the plug  20  and for the cable  22  during the actuation of the gas generator  14 . For this purpose, the width W of the securing flap  26  is selected to have at least the dimension of the passage opening  42 .  
      The gas bag  12  consists of a large-surface, single-folded layer of fabric onto which two protection layers  36  made of gas bag fabric are sewed in the vicinity of the gas generator  14  (see  FIGS. 7   a  and  7   b ). First of all, the protection layers  36  form a pocket  19  for the gas generator. Secondly, each of the protection layers  36  has a strip-like projection  26   a  that is formed in one piece with the appertaining protection layer  36 . When the gas bag  12  is assembled, the projections  26   a  are sewed together and then form the securing flap  26 .  FIG. 6  shows the unfolded cut-out of the gas bag  12  in the area of the protection layers  36 .  
      The arrows in  FIGS. 7   a  and  7   b  indicate the direction of the warp and weft threads in the protection layers  36 .  
      The gas bag  12  has another fabric strip  40  that is used to hold the folded gas bag  12  together before it is expanded. The fabric strip  40  is provided in a known manner with a weakened zone, for example, a tear line, so that it releases the gas bag  12  when the gas generator  14  is ignited.