Perforator for weblike materials with means for modifying the interval between consecutive lines of perforations

摘要

The perforating unit comprises: a support (23) with at leat two fixed counterblades (25A, 25B); a first roller (27) revolving about its own axis and carrying a first series of rotary blades (29) acting in combination with a first (25A) one of said fixed counterblades; a second roller (31) revolving about its own axis nd carrying a second series of rotary blades (33) acting in combination with the second (25B) one of said fixed counterblades. The blades of the first series are arranged at a different pitch from the blades of the second series of blades.