Motor vehicle instrument panel with flexible tethering hinged air bag deployment door

Claim 1

In combination, a motor vehicle structure, an air bag system including an inflatable air bag mounted on said vehicle structure, a molded instrument panel made of plastics material mounted on said vehicle structure and covering said air bag, said instrument panel having a tear seam defining an air bag deployment door in said instrument panel that is torn outward from said instrument panel along said tear seam by the force of said air bag on inflation to form an opening in said instrument panel allowing deployment of said air bag into a passenger space in said vehicle structure, said door having an integral elongated mounting/hinge flange located on an inner side, first fastening means fastening said mounting/hinge flange to said vehicle structure to normally aid in securing said instrument panel in place on said vehicle structure and supporting said door against an inward pushing force when said air bag is not being deployed, said mounting/hinge flange being flexible in a limited temperature range to act as a hinge to swing said door outward for air bag deployment while retaining said door to said vehicle structure but subject to breakage along a juncture zone with said door at temperatures below said limited temperature whereby a door portion is separated from said mounting/hinge flange and thereby from said vehicle structure, and a flexible tethering hinge for said door portion formed of flexible sheet material that remains flexible at temperatures substantially below said limited temperature range, said tethering hinge spanning said juncture zone and extending substantially the length thereof along an inner side of said door portion and one side of said mounting/hinge flange that adjoins said juncture zone, said tethering hinge having one margin that is located against said one side of said mounting/hinge flange at a location remote from said juncture zone and having another margin that is located against said inner side of said door portion and having an intermediate portion that is located between said margins and spans said juncture zone, second fastening means fastening said one margin to said mounting/hinge flange, third fastening means fastening said other margin to said door portion without penetrating said door portion, and said intermediate portion of said tethering hinge having a fold that extends along and outward of said juncture zone and unfolds to retain said door portion to said vehicle structure when said juncture zone breaks.