Patent ID: 8414462
Filing Date: 2013-04-09
Classification: B26F,B31B,B31D,B65D

Abstract:
1. A method of forming a pressed paper end which mitigates wrinkling or tearing of the paper end, the paper end having a circular covering portion having a peripheral area, an annular chuck wall area extending from the covering portion to an annular rim, and a flange area extending from the annular rim, the method comprising the steps of: (a) providing a die press having an upper tool section moveable relative to a lower tool section, an upper draw ring surrounding the upper die center, and an upper cutting edge, the upper tool section comprising a male upper die center having an outer facing wall shaped like an inverted truncated cone and forming an angle α with the vertical, the lower tool section comprising a lower cutting punch having an inner facing wall shaped like a right-side up truncated cone and forming the same angle α with the vertical; (b) feeding a paper based web to the die press; (c) advancing the upper tool section toward the lower tool section until the upper draw ring cooperates with the lower cutting punch to clamp the flange area of the paper disk while allowing the flange area to slip a little between the upper draw ring and the lower cutting punch; (d) shearing the paper end from the feed web by the upper cutting edge; (e) forcing the paper end disk toward the lower die center while the upper draw ring and the lower cutting punch maintain tension on the flange area; (f) bringing the upper die center and the lower cutting punch together so that the chuck wall is squeezed between the outer facing wall and the inner facing wall; and (g) forming the pre-pressed paper end.