Bag Bottom Strip for Stable Packaging
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Solution Overview
Problem
Existing plastic packaging bags with gussets and continuous manufacturing from a single film face stability issues when filled with very light products, as the folded-down bottom creates extra thickness, leading to instability both when empty and after filling.
Innovation Solution
A method involving a fold line parallel to the bottom strip's length and a marking line on the wall, allowing for a flat bottom without extra thickness, achieved through partial weld lines and a bottom strip that can be of the same or different material, ensuring stability during and after filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bottom is formed by folding down and fixing the film continuously during manufacturing, then the bag can be produced continuously from a single plastic film, but the folded bottom creates extra thickness that deteriorates vertical stability when filled with light products
Solution Approach 1:
The invention separates the bottom formation process from the main bag body by introducing a distinct bottom strip that is positioned and fixed separately, rather than folding the main film body to create the bottom. This segmentation allows the bottom to be a flat, stable element independent of the bag walls.
Solution Approach 2:
The invention introduces a bottom strip as an intermediary element between the bag walls and the ground surface. This bottom strip acts as a mediator that provides a flat, stable base without requiring the main film to be folded and thickened, thus resolving the stability issue while maintaining continuous manufacturing.
2Device complexity
If the bottom is formed by folding down the film, then the bottom can be integrated with the bag walls, but this creates an extra thickness that prevents stable positioning of light products
Solution Approach 1:
The bottom is segmented as a separate functional element (bottom strip) from the bag walls, positioned and fixed independently. This allows the bottom to be thin and flat for stability, while the bag walls maintain their structural integrity, achieving both integration and stability without extra thickness.
Solution Approach 2:
The invention applies different structural qualities to different parts of the bag: the bottom strip is flat and thin to provide stability, while the bag walls are folded and welded to provide structural strength. This local differentiation resolves the contradiction between integration and stability.
3Ease of manufacture
If the bag bottom is folded down and fixed on one wall, then the bottom can be formed continuously, but the extra thickness created makes the bag unstable when empty and after filling with light products
Solution Approach 1:
The bottom strip serves as an intermediary element that is continuously positioned and fixed during manufacturing, providing a flat stable base without requiring the main film to be folded. This mediator approach enables continuous manufacturing while eliminating the extra thickness problem.
Solution Approach 2:
Instead of folding the main film body to create the bottom (which creates thickness), the invention inverts the approach by positioning a separate bottom strip from the inside, creating a flat bottom without inversion or thickening of the main structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in a bag with a perfectly flat bottom, enhancing vertical stability, enabling efficient packaging of light products like cereals and maintaining stability before and after filling.
Implementation Method 1
The external plies thus produced are generally assembled by welding operations. The bottom strip is then superimposed on the internal face of the walls and bellows... The fixing of the bottom strip is then carried out by welding over its entire width.
Data Source
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AI summary
The method involves subjecting a plastic film to successive folding operations for forming lateral gussets (1c, 1d) between two walls (1a, 1b). The film is transversely cut according to a desired height of a packaging bag (1). A transversal opened end of the wall (1b) is externally folded to open the gussets and flatly position the gussets by forming a triangle. A plastic band (2), which serves as a bottom, is fixed on an internal surface of a part of the wall (1b), an internal surface of the gussets arranged in the triangle and on an internal surface of the wall (1a).