Sheet-guiding drum assembly for sheet-fed rotary printing machines

Sheet-guiding drum assembly for sheet-fed rotary printing machines, the assembly comprising a rotatable drum formed with a casing surface and a casing foil disposed peripherally around said casing surface so as to have an outer diameter, said casing foil having an edge leading in direction of rotation of said drum, and an edge trailing in said direction, respective tensioning locations at least at said leading and trailing edges of said casing foil at which said casing foil is fastened to said drum, adjustment means located at least at one of said tensioning locations for imparting a tensioning movement to said casing foil in peripheral direction of said casing surface, a member arranged beneath the casing foil and on the casing surface of the drum, said member having a multiplicity of individual support elements for yieldingly supporting said casing foil over the entire surface thereof on said casing surface of said drum, and means for substantially uniformly varying the height of said member on the casing surface and thereby substantially uniformly varying said outer diameter of said casing foil over substantially the entire periphery thereof.