Patent ID: 8833216
Filing Date: 2014-09-16
Classification: B26F,Y10T

Abstract:
1. A tool for perforating a polymeric film which comprises a support substrate and a plurality of projections for forming perforations extending from the substrate, with the projections being arranged in a pattern that comprises a series of spaced-apart parallel lines of projections in defined spaced-apart areas on the surface of the support substrate, with these areas being separated by areas of the substrate that have no projections in the areas, wherein at least one area of projections is arranged to achieve controlled loading and unloading of the film in a nip between the support substrate and another surface in use of the tool to perforate a polymeric film by having a leading edge as viewed from within the nip that is narrower than an average width of the projections in the area so as to dampen an initial loading of the nip, wherein the width of the area increases from the leading edge to a wider part of the area, with the projections being cross-shaped with four outwardly extending arms having side walls that have straight sides that are tapered upwardly and inwardly from the support substrate at an angle theta (θ) that is at least 5°, with the angle being measured in relation to imaginary lines extending perpendicularly to the substrate at the locations at which the side walls contact the substrate.