Retaining Seams for Open Sack Grip and Gusset Integrity
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Solution Overview
Problem
Open-mouth bags with side gussets are prone to tearing or bursting when encountering sharp objects, leading to product loss and dust pollution, and existing welding methods struggle to create both a tight seal and practical handles, especially with materials like HDPE or PP, which are difficult to weld and result in either a hard, brittle weld seam or incomplete connection of side gussets.
Innovation Solution
A packaging machine and method that introduces additional retaining seams into the side folds of open-mouth bags using a separate welding device, generating a higher welding temperature to fuse all layers of the side gussets, providing a grip option and improving the bag's appearance, while ensuring the seams are elastic to withstand dynamic loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If open-mouth bags are made of tubular film for high water resistance, then water resistance is improved, but the bags are prone to tearing or bursting upon contact with sharp objects
Solution Approach 1:
The patent uses a composite structure consisting of an inner tubular film layer (providing water resistance) and an outer ribbon fabric layer (providing tear resistance). This multi-layer composite construction allows the bag to simultaneously achieve both water resistance and high strength against sharp objects.
2Strength
If open-mouth bags are made of HDPE or PP tape fabric for high strength, then tear resistance is improved, but the bags are considerably more difficult to weld
Solution Approach 1:
The patent combines HDPE or PP tape fabric (providing strength) with a weldable inner film layer. The inner layer is designed to be weldable while the outer fabric layer provides the necessary strength, thus resolving the contradiction between ease of welding and strength.
Solution Approach 2:
The patent applies different material properties to different layers: the inner layer is made weldable for easy sealing, while the outer layer maintains high strength characteristics. This local differentiation of material properties allows both welding ease and strength to be achieved in their respective functional zones.
3Ease of manufacture
If only the inner layer is welded together in open-mouth bags made of ribbon fabric, then welding ease is improved, but the outer areas of the side gussets are not fully connected
Solution Approach 1:
The patent divides the welding process into two segments: first welding the inner layer for ease of manufacture, then adding additional retaining seams in the side folds to connect the outer areas. This segmented approach allows both welding ease and structural stability to be achieved through sequential welding steps.
Solution Approach 2:
The patent performs preliminary welding of the inner layer first, then adds the additional retaining seams as a subsequent action. This preliminary action approach allows the welding process to proceed in stages, ensuring both ease of manufacture and complete connection of side gussets.
4Stability of the object's composition
If welding temperature is increased to connect all layers of ribbon fabric, then side gusset connection is improved, but the weld seam becomes hard and brittle
Solution Approach 1:
The patent applies different welding temperatures to different areas: a first welding temperature for the inner layer and a second, higher welding temperature for the outer ribbon fabric layers in the side folds. This local differentiation ensures proper connection without making the entire weld seam hard and brittle.
Solution Approach 2:
The patent segments the welding process into two distinct steps with different temperature parameters. The first welding step connects the inner layer at a lower temperature, while the second step connects the outer fabric layers at a higher temperature, thus achieving both connection and flexibility.
5Ease of operation
If additional welding device is added to introduce retaining seams, then grip option and appearance are improved, but device complexity increases
Solution Approach 1:
The additional welding device is designed to perform multiple functions: it not only creates retaining seams for grip options but also improves the visual appearance by connecting the side gussets. This multi-functionality justifies the added device complexity by delivering multiple benefits from a single addition.
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 provides a reliable, elastic grip option for open-mouth bags made of various materials, ensuring the bag remains closed even if the retaining seam tears, and maintains a visually appealing shape without compromising the seal of the filled product.
Implementation Method 1
A closing device is provided which, when closing the filling opening, generates a welding temperature that is at least 50 Kelvin higher in the area of the side folds than in a central area of the bag wall
Implementation Method 2
generates a welding temperature to fuse all layers of the side gussets
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Packaging machine and method for filling product into open bags which are provided with side folds, and an open bag of this type. The packaging machine comprises a filling device, in order to fill the open bags from a filling end. A closing device is provided, by way of which, after the filling operation, the filling end can be closed in a completely sealed manner with a welded seam. An additional welding device is provided. The additional welding device is suitable and configured for introducing two additional holding seams which are spaced apart laterally from one another in the transverse direction and are oriented approximately parallel to the welded seam into the side folds of the open bags.