Patent ID: 8128098

Claim:
A gasket, comprising: a middle layer surrounding a combustion opening, said middle layer comprising an upper surface and a lower surface defining a first planar portion, a wave portion and a second planar portion, wherein said first planar portion extends entirely circumferentially about said combustion opening for a predetermined radial distance, said wave portion entirely circumferentially extends about said first planar portion for a predetermined radial distance, said wave portion comprising a plurality of continuously connected crests and troughs, wherein vertices of all of said crests and troughs are located above and below, respectively, said upper and lower surfaces, wherein said second planar portion extends entirely circumferentially about said wave portion for a predetermined radial distance; a first intermediate layer having an upper surface and a lower surface, said surfaces being substantially entirely planar and parallel to one another, said surfaces also being substantially parallel to said first planar portion and said second planar portion of said middle layer, said upper and said lower surfaces extending in a planar fashion from said combustion opening beyond said wave portion of said middle layer, wherein said lower surface of said first intermediate layer abuts at least said vertices of said waves; a second intermediate layer having an upper surface and a lower surface, said surfaces being substantially planar and parallel to one another, said surfaces also being substantially parallel to said first planar portion and said second planar portion of said middle layer, said upper and said lower surfaces extending in a planar fashion from said combustion opening beyond said wave portion of said middle layer, wherein said upper surface of said second intermediate layer abuts at least said vertices of said troughs; an uppermost active layer located above said first intermediate layer, said uppermost active layer comprising a first planar portion, a first bead portion, and a second planar portion, in order, from said combustion opening, wherein said first planar portion and said second planar portion are parallel to said first intermediate layer, and wherein said first bead portion is vertically aligned with said wave portion of said middle layer; and a lowermost active layer located below said second intermediate layer, said lowermost active layer comprising a first planar portion, a first bead portion, and a second planar portion, in order, from said combustion opening, wherein said first planar portion and said second planar portion are parallel to said second intermediate layer, and wherein said first bead portion is vertically aligned with said wave portion of said middle layer.