Means for perforating plastic films

Claim 1

IN A DEVICE FOR PRODUCING A SCORING LINE IN PLASTIC FILM MATERIAL OF THE TYPE DESCRIBED, WHEREIN THE PLASTIC FILM IS MOMENTARILY HELD STATIONARY WHILE THE SCORING LINE IS BEING MADE, A STATIONARY ANVIL POSITIONED FOR CONTACT WITH ONE FACE OF THE PLASTIC FILM, SAID ANVIL HAVING A SERIES OF ALIGNED, SPACED, SINGLE CUTTING BLADES, EACH BLADE CONSISTING OF A STRAIGHT KNIFE EDGE TERMINATING IN A SHARP CORNER AT EACH END, A COOPERATING HARD-SURFACED ROLLER POSITIONED FOR CONTACTING SAID ANVIL AND THE OPPOSITE FACE OF SAID PLASTIC FILM, MEANS FOR MOVING SAID ROLLER ALONG SAID ANVIL AND SAID INTERPOSED PLASTIC FILM, AND MEANS CAUSING SAID ROLLER TO PRESS AGAINST SAID KNIFE EDGES OF SAID BLADES AND TO STRIKE AGAINST SAID CORNERS OF SAID BLADES IN SUCCESSION AND AS SAID ROLLER MOVES ALONG SAID ANVIL, WHEREBY THE ENGAGEMENT OF SAID ROLLER WITH SAID BLADE CORNERS AND THE INTERPOSED PLASTIC FILM WILL CAUSE PUNCTURING OF SAID PLASTIC FILM AT SAID CORNERS AND FACILITATE THE SCORING AND CUTTING OF SAID PLASTIC FILM ALONG SAID KNIFE EDGES.