Variable tension gusseting system

A method for making a flexible package, said method comprising the steps of:

• a) forming a tube of packaging film on a vertical form, fill, and seal machine;
• b) forming a vertical crease in said tube of packaging film prior to sealing said tube horizontally;
• c) forming a first horizontal seal on said tube, wherein said first horizontal seal includes a portion of said vertical crease;
• d) forming a second horizontal seal on said tube, wherein said second horizontal seal includes a portion of said vertical crease;
• and
• e) cutting said tube segment from the remainder of said tube at said second horizontal seal, thus forming a flexible package having a crease along one edge;
• wherein the crease of step b) is formed by imparting a tension force on said tube with at least three extensions extending below the bottom of a forming tube on said vertical form, fill, and seal machine, and a pivoting gusseting mechanism positioned between two of said at least three extensions;
• said extensions applying said tension on said tube from inside said tube pressing outwards on said tube, and said gusseting mechanism applying said tension on an exterior surface of said tube pressing inwardly on said tube;
• and
• wherein said gusseting mechanism comprises a substantially planar plow mechanism having a protruded tucker device, and wherein said plow mechanism is allowed to rotate by its own weight so that said protruding tucker device engages said outer surface of said film tube exerting a generally constant force on said film tube, wherein the forming of said crease requires no pneumatic or cam-driven actuation to impart said crease.

A method for making a flexible flat-bottomed package, said method comprising the steps of:

• a) advancing a continuous sheet of packaging film through a vertical form, fill, and seal machine;
• b) forming said continuous sheet into a tube on said vertical form, fill, and seal machine and thereafter forming a longitudinal seal on said tube;
• c) forming two vertical creases in said tube with two gusseting mechanisms prior to sealing said tube horizontally, wherein said gusseting mechanisms are positioned on opposing sides of said tube and each comprise a mechanical pivoting tucker mechanism wherein said tucker mechanism comprises a substantially planar plow mechanism having a protruded tucker device, and wherein said plow mechanism is allowed to rotate by its own weight so that said protruding tucker device engages said outer surface of said film tube exerting a generally constant force on said film tube, wherein the forming of said crease requires no pneumatic or cam-driven actuation to impart said crease;
• d) forming a first horizontal seal on said tube, wherein said first horizontal seal includes a portion of said two vertical creases;
• e) advancing said tube a specified segment length;
• f) forming a second horizontal seal on said tube, wherein said second horizontal seal includes a portion of said two vertical creases;
• and
• g) cutting said tube segment from the remainder of said tube at said second horizontal seal, thus forming said flat-bottomed package having two vertical gussets along two opposite vertical edges.