Two stage cutter arrangement for forming an air bag deployment opening

Claim 1

An arrangement for forming an air bag deployment opening in a trim piece of a passenger compartment of a vehicle, said trim piece having an air bag stored in a canister mounted behind a section thereof, the arrangement comprising: a trim piece substrate panel formed with an opening located over said air bag canister; at least one deployment door substrate panel fit within said opening in said trim piece substrate panel, said door substrate panel formed with a plurality of sides, one side thereof hinged to said trim piece substrate along the perimeter of said opening, the other sides thereof free to allow said door substrate panel to swing out of said trim piece substrate opening; a covering layer extending over the outside of said trim piece and said door substrate panel; a first stage cutter comprising a cutter panel having sides substantially coextensive with said door substrate panel, cutter panel lying inside said door substrate panel and hinged along the same side as said door substrate panel, initially swung inwardly from said door substrate of piercing elements extending outwardly from said cutter page each element having a piercing point located to contact the inside of said covering layer at points on said pattern along said door substrate panel sides when said cutter panel is swung outward to abut said door substrate panel and said piercing points are thereby brought into contact with the inside of said covering; an out turned perimeter rim formed along the perimeter of said other sides of said door substrate panel extending outward to a level adjacent to the inside of said covering layer, whereby said rim of said door substrate panel can apply a second stage severing pressure on said covering layer after penetration by said first stage cutter piercing elements in a pattern defined by said other unhinged sides thereof as said air bag forces said substrate door panel to hinge open upon inflation of said air bag.