Self-Opening T-Shirt Bag Structure for Tear-Resistant Dispensing
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Solution Overview
Problem
Current plastic bags used for grocery and retail purposes are prone to tearing and ripping, especially at the handle and mounting tab areas, which affects their durability and efficiency during use, and there is a need for improved designs that enhance productivity and cost-effectiveness for checkout clerks.
Innovation Solution
A T-shirt-styled bag design featuring stress relief notches, reinforced handles, and a mounting tab structure that allows easy mounting and removal from dispensing racks without leaving remnants, with a focus on optimizing handle strength and tear resistance through specific geometric configurations and materials like thermoplastic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mounting tab with perforated line is used to allow easy removal from dispensing rack, then ease of operation is improved, but the bag mouth becomes susceptible to tearing and ripping
Solution Approach 1:
The patent applies stress relief notches that convert the harmful stress concentration at the bag mouth edge into a beneficial feature by providing controlled stress distribution paths. The notches are positioned to redirect tensile forces away from the vulnerable bag mouth region while maintaining the integrity of the mounting tab perforation system.
Solution Approach 2:
The patent introduces localized structural modifications in the form of stress relief notches at specific positions around the bag mouth perimeter. These notches create zones of reduced material continuity that locally manage stress distribution, allowing the rest of the bag structure to maintain full strength while the mouth area gains tear resistance.
2Strength
If the handle and mounting tab area are reinforced to prevent tearing, then strength is improved, but the bag becomes more complex and harder to manufacture
Solution Approach 1:
The patent divides the handle and mounting tab structure into distinct functional zones with specific geometric features. The handles are formed with integrated apertures and the mounting tabs are positioned as separate elements, allowing each component to be optimized independently while simplifying the overall manufacturing process through modular design.
Solution Approach 2:
The patent modifies geometric parameters of the handle and mounting tab areas, including the shape and position of apertures, the dimensions of stress relief notches, and the thickness of material in critical zones. These parameter changes enhance strength and tear resistance while maintaining compatibility with standard manufacturing processes.
3Ease of operation
If the bag mouth is made wider for easy filling, then ease of operation is improved, but the bag becomes more susceptible to tearing at the mouth edges
Solution Approach 1:
The patent converts the vulnerability of wide bag mouth edges to tearing into a benefit by introducing stress relief notches that actively manage stress distribution. The notches are strategically positioned to intercept and redirect forces that would otherwise concentrate at the mouth edges, transforming a structural weakness into a stress-management feature.
Solution Approach 2:
The patent employs curved geometries in the stress relief notches and handle designs to distribute stresses more evenly across critical areas. The curved paths of the notches and the rounded contours of the handles reduce stress concentration points compared to sharp angular features, enhancing tear resistance while maintaining wide mouth opening.
Data Source
AI summary
A tabless, self-opening T-shirt-styled thermoplastic bag is provided having a handle, stress relief notch, and mounting tab structure for providing a wide-opening bag mouth and a bag having high weight carrying capacity. Handles have a narrow upper portion, a wide middle portion and a narrow lower portion. Handle mounting apertures are provided in the wide middle portion, which projects inwardly above the mouth of the bag. The handle mounting apertures are formed by a blade having an elongate section that is bent to form an obtuse angle. The handle mounting aperture has a sufficient width for accommodating arms of a dispensing rack and a height about three times as great as the width. The bag has a central mounting tab extending above the mouth of the bag and between the handles. A stress relief notch having a reasonably tight radius of curvature is provided between each handle and the mounting tab. The mounting tab has a mounting aperture formed by two blades meeting at a sharp corner, the corner having essentially no radius of curvature. A severable region is provided between the corner and an outer edge of the mounting tab, which can tear as the bag is removed from a mounting hook on a dispensing rack. Multiple bags are aligned and bonded together to provide a unitary pack, where pulling one bag off a dispensing rack pulls an adjacent bag open.