Knife roller

A knife roller for cutting out several openings in flat material and for disposing of cut-out portions, comprising a roller cylinder body having a longitudinal roller axis, a shell section (42) surrounding at least a portion of said roller cylinder body, cutting knives secured to said shell section, a plurality of suction holes (43) passing through said shell section, said suction holes (43) being arranged in rows (44) extending in parallel to said longitudinal roller axis, said rows (44) being circumferentially spaced from one another around said shell (42), a plurality of suction channels (46) arranged so that one suction channel (46) is provided in common for all suction holes (4) of one suction hole row (44), whereby each suction hole row (44) has its own suction channel (46), said suction channels (46) extending in parallel to said longitudinal roller axis, a first suction air control duct (48) exclusively communicating with a first suction channel (44a) of said plurality of suction channels (46), second and third suction air control ducts (49, 50), a first valving disk (6) arranged for communicating said second suction air control duct (49) with any one of said plurality of suction channels (46) except said first suction channel (44a), a second valving disk (57) arranged for communicating said third suction air control duct (50) with anyone of said plurality of suction channels (46) except said first suction channel (44a), flow conduit means for providing communication from a source of suction to said suction holes (433) through said suction channels (46), and through said suction air control ducts (48, 49, 50) of which said second and third ducts are selectively controlled by said first and second valving disks (56, 57), whereby substantially any surface portion of said shell section is selectable for an application of suction through the suction holes in said surface portion.