Method and apparatus for producing stacks of interleaved material sheets

An apparatus for producing a stack of interleaved material sheets meshing with one another, comprising a stacking station, two co-operating stacking roller means (8, 9) arranged to form a stack of sheets (3;

• 3a) at said stacking station, roller means (11, 13, 14) for transporting and guiding material webs (3, 3a) to said stacking roller means (8, 9), said roller means comprising web cutting means (12) for cutting said material webs into individual sheets, each of said stacking roller means comprising crimping-and folding-edge means (16, 20, 21) for creasing and folding each individual sheet (3, 3a), sheet gripper means (18) mounted on each of said stacking roller means (8, 9) for rotation with said stacking roller means, said sheet gripper means holding a sheet temporarily, each sheet gripper means (18) comprising a journal pin (35) and a suction gripper flap (18) tiltably mounted with said journal pin (35) for journalling said suction gripper flap (18) in addition to rotation with said stacking roller means, and suction means (23, 24, 26) arranged at a circumference of each stacking roller means (8, 9), said suction means cooperating with said crimping- and folding-edge means (16, 20, 21) and with said gripper means (18) for a firm and positive handling of each sheet (3, 3a) to form said stack in which the sheets are interleaved in a U- or zig-zag-configuration, said suction means comprising at least one suction element (23) in each suction gripper flap of said sheet gripper means (18), whereby said first suction element (23) tilts back and forth with its suction gripper flap, at least one second suction element (24) in said stacking roller means (8, 9) behind the respective suction gripper flap of said gripper means for cooperation with said suction gripper flap (18), at least one third suction element (26) arranged on said stacking roller means (8, 9) for cooperation with its respective crimping- and folding-edge means, and means (37, 38, 39) for controlling a tilting movement of said suction gripper flap (18) between a sheet gripping position and a release position.