Abstract: A conventional fin-type seam formed on tubed bag forming sheet material provided on one face with heat sealable material, has heat sealed overlapping edge portions forming the seam. The fin slides over a back-up plate extending between it and the body of the tube to prevent scuffing of the heat sealable material with consequent seal failure. A tracking wheel engaging the fin presses it against the back-up plate, and maintains alignment.

Abstract: This invention is a heatseal die which is intended to replace one die of a pair of heatseal dies normally employed in a packaging machine. The die of the invention differs from the die normally employed in that the lower portion of the die face, which forms the heatseal at the top of the package, has ribs which are horizontal instead of vertical. Being horizontal, the ribs intersect the vertical ribs of an opposing die, instread of meshing with them as the ribs of the die normally employed do. The pattern of point seals formed where the ribs intersect forms a good gastight seal but reduces the force required to break the seal, thereby permitting the package to be opened more easily.

Abstract: A conventional fin-type seam formed on tubed bag forming sheet material provided on one face with heat sealable material, has heat sealed overlapping edge portions forming the seam. The fin slides over a back-up plate extending between it and the body of the tube to prevent scuffing of the heat sealable material with consequent seal failure. A tracking wheel engaging the fin presses it against the back-up plate, and maintains alignment.