Variable tension gusseting system
A vertical stand-up pouch, flat bottom bag, or flexible package, and method for manufacturing same, constructed by modification to existing vertical form and fill packaging machines. The invention involves producing a vertical stand-up pouch or flat bottom bag from a single sheet of packaging film by forming one or two vertical creases along opposing sides of the packaging film tube prior to forming a transverse seal on the tube. The vertical crease is formed using a pivoting tucker mechanism positioned outside the packaging film tube and between two forming plates positioned inside the packaging film tube. A novel method is also disclosed for adjusting the orientation of labeling on the packaging film, which results in the production of innovative packages.
1. A gusseting mechanism for imparting a longitudinal crease in a film tube on a vertical form, fill, and seal machine, comprising:
a) a substantially planar plow mechanism, which includes a pivot point formed perpendicularly through said plow mechanism and a protruding tucker device which projects from an edge of said plow mechanism, wherein said pivot point is offset vertically and laterally from said protruding tucker device; and
b) a rod pivotally attached to said pivot point, said rod having one end operable to be fixably attached to a frame support structure of said machine so that the planar surface of said plow mechanism is oriented substantially parallel to a longitudinal axis of said film tube and substantially perpendicular to an outer surface of said film tube,
wherein said plow mechanism is rotatable about said rod so that said protruding tucker device engages said outer surface of said film tube exerting a generally constant force on said film tube forming said crease; and
wherein said plow mechanism is rotatable by its own weight, and requires no pneumatic or cam-driven actuation to impart said longitudinal crease.
2. The gusseting mechanism of claim 1 , wherein said pivot point comprises an aperture in said planar surface and a pivotal bearing inserted therein.
3. The gusseting mechanism of claim 1 , wherein said protruding tucker device has a rounded profile.
4. The gusseting mechanism of claim 1 , further comprising a biasing mechanism attached to said plow mechanism, wherein said biasing mechanism biases said plow mechanism's rotation about said rod.
5. The gusseting mechanism of claim 4 , wherein said biasing mechanism comprises a counter-weight device.
6. The gusseting mechanism of claim 1 , wherein said substantially planar plow mechanism comprises a generally L-shaped plate.
7. The gusseting mechanism of claim 6 , further comprising a flange plate attached to the outer edge of said L-shaped plate.
8. The gusseting mechanism of claim 1 , wherein said rod is threaded.
9. The gusseting mechanism of claim 1 , wherein said plow mechanism is pivotally responsive to a change in the surface tension of said film tube.
10. A method for imparting a longitudinal crease in a film tube on a vertical form, fill, and seal machine, comprising:
(a) attaching a mechanical gusseting mechanism to said vertical form, fill, and seal machine, wherein said gusseting mechanism includes a rod fixably attached to a frame support structure of said machine and a substantially planar plow mechanism pivotally attached perpendicularly to said rod, said planar plow mechanism haying a protruding tucker device that is positioned below a forming tube of said vertical form, fill, and seal machine so that the planar surface of said plow mechanism is oriented substantially parallel to a longitudinal axis of said film tube and substantially perpendicular to an outer surface of said film tube;
(b) allowing said planar plow mechanism to rotate about said rod 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 forming said crease in said film tube, wherein the forming of said crease requires no pneumatic or cam-driven actuation to impart said longitudinal crease.
11. The method of claim 10 , further comprising biasing said planar plow mechanism to influence the rotation of said planar plow mechanism about said rod.
12. The method of claim 11 , wherein said biasing step comprises adding a counter-weight device to said planar plow mechanism.