| 摘要 |
In a hole punching apparatus (5) for rotary punching of continuously extending rows (7) of holes in an endless web of paper (6) the punch wheels (1, 2) are provided with a peripherally protruding rim (18, 19) for mounting punch needles (13) or die rings (14) of the punch tools (12) in associated reception holes (16, 17). A plurality of support rings (25a, 25b, 25c) serves to support the punch needles in a specific support depth. All of these rings (25a, 25b, 25c), except the smallest one (25a), are provided with a plurality of cutouts (28b, 28c) along the periphery, each of which forms a clearance for a punch needle (13) so that this will rest on a smaller ring when the cutout (28b, 28c) is positioned radially opposite a reception hole (16, 17), while the punch needle (13) or the die ring (14) will rest on the largest one of the rings (25b, 25c) whose cutouts (28b, 28c) are positioned between the reception holes (16, 17). The support depth can hereby be changed stepwise so as to fit punch needles (13) which have been reground. |
