Tiltable extrusion die having sealing lip connected by thin annular zone

Claim 1

An extrusion head for extruding plastic material, said head comprising: a body having a hollow generally cylindrical shape with an internal surface defining at least in part a first duct extending in an axial direction and having a first diameter; a die having one end extending into said first duct, said die having a generally cylindrical external surface with a diameter less than said first diameter to permit tilting of said die relative to said axial direction, said die having an internal surface defining at least in part a second duct; and a sealing device for sealing a junction between said first duct and said second duct to permit flow of a plastic material under high pressure between the first and second ducts even though said die is tilted relative to said axial direction, said sealing device comprising a metal annular lip protruding radially from the external cylindrical surface of said die at said one end of said die, said lip being connected to said die by a thin annular zone, said lip having an external cylindrical surface abutting the internal surface of said body under a mechanical bias due to dimensional tolerances of said external surface of said lip and said internal surface of said body, said annular zone being thin enough to flex when said die is not aligned in said axial direction with said first duct.