Patent ID: 7059232

Claim:
A method of forming a tamper indicating closure from a plastic closure having a base wall and a peripheral skirt, which includes the steps of: (a) providing a primary cutting knife having an interrupted cutting edge for cutting an interrupted circumferential score, said interrupted circumferential score including circumferentially spaced cuts and a plurality of bridges respectively separating said spaced cuts, said interrupted cutting edge of said primary knife having a cross section with opposed tapered surfaces forming opposite identical angles relative to a plane through the center of said primary cutting knife and intersecting the cutting edge of said knife, (b) supporting said primary cutting knife in a fixed position on a first support for cutting at a first depth into said peripheral skirt, (c) providing a secondary cutting knife having a continuous cutting edge for cutting a circumferential score, said continuous cutting edge of said secondary knife having a cross section with opposed tapered surfaces forming opposite identical angles relative to a plane through the center of said secondary cutting knife and intersecting the cutting edge of said secondary cutting knife, both said primary cutting knife and said secondary cutting knife having said tapered surfaces adjacent to said cutting edges forming an angle A with the central plane of each knife, and both said tapered surfaces spaced from said cutting edges forming an angle B, less than said angle A, with the central plane of each knife, (d) supporting said secondary cuffing knife in a fixed position on a second support for cuffing a second depth into said peripheral skirt, said second support positioning said secondary cuffing knife such that said continuous cuffing edge is aligned with said interrupted circumferential score, (e) variably positioning said primary cuffing knife on said first support, and variably positioning said secondary cutting knife on said second support independent of said primary cuffing knife and said first support, and (f) moving said plastic closure successively past said primary cuffing knife and said secondary cuffing knife initially to bring the peripheral skirt of said plastic closure into contact with said interrupted cuffing edge of said primary cuffing knife to cut said interrupted circumferential score having said plurality of circumferentially spaced bridges, and thereafter to bring said peripheral skirt of said plastic closure into contact with said continuous cutting edge of said secondary cutting knife to cut in and along said interrupted circumferential score to dimension accurately the radial thickness of said bridges.