Method of making a tear line-forming perforation in a sealed marginal portion of a bag and a sealed bag formed thereby

摘要

A unique preferably Y-shaped tear line-forming perforation is formed in the sealed marginal portion of a flat bag made of confronting panels of synthetic plastic material sealed together at marginal portions thereof. The perforation is formed with a unique bag-puncturing tool having a faceted, tapered tool head having preferably only three straight longitudinally extending bag-cutting edges converging to a bag-puncturing point at the end of the tool head. The sealed bag is placed against a support wall having a tool-receiving aperture therein and the bag-puncturing point of the tool head is positioned outside of the inner margin of a sealed marginal portion of the bag and pushed through the bag into the aperture of the support wall with an orientation which produces a Y-shaped perforation outside of said inner margin with one leg of the perforation extending from the point of intersection of the legs of the perforation in a direction away from the adjacent edge of the bag to establish a tear line direction which extends into a sealed bag portion to form a desired bag opening by tearing the bag through this tear line-determining leg of the perforation.