Patent ID: 7210324

Claim:
A two step process for producing a profiled sheet comprising: (1) engaging a sheet with (a) a roller having one or more of profiled rolls or (b) a ram-like deformation tool having a generally horizontal sheet-engaging surface to provide a sheet with corrugations ( 4 ) which run obliquely with respect to the edges of the sheet with a substantially constant angle of inclination, and (2) deforming an edge region of the resultant corrugated sheet with a ram-like deformation tool (b) having a generally horizontal sheet engaging surface which is alternately brought into contact with the edge region and removed therefrom so as to provide the edge part with corrugation which runs at an angle of inclination with respect to the edge if the sheet which differs from said constant angle or inclination in step (1), said edge region constituting 1% to 10% of the entire sheet.