Covers for airbags are well known. For example, WO 96/07563 discloses a folded airbag that is packed into a cover. The cover is provided with a frangible seam which, in the event of airbag deployment, tears as the airbag inflates and releases the airbag as quickly and with as little hindrance as possible.
After an airbag that has been folded and is being placed into a cover provided with a frangible seam, the frangible seam can tear open at the initial and final portions of the cover or unravel. To prevent this, in the prior art the initial and final portions of the frangible seam were sewn using back tacking. That is to say the frangible seam is stitched more than once over a length of a few centimeters in both end portions of the seam in these regions. This makes it possible to prevent the airbag package from opening prematurely during the process of placing the airbag inside the cover, during further production or during shipping. However, this approach is disadvantageous because if the airbag module is activated in exceptional cases the airbag cannot unfold completely and deploy from its cover, since the frangible seam is not torn open in the regions of the back tacking.
USPTO Backgrounds
USPTO Backgrounds