Inverted T-Shaped Endstops for Slider Zippers
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Solution Overview
Problem
Reclosable packages or bags with zipper flanges that are co-planar or attached to the outside of the zipper profiles face issues where distending forces can pry the slider off the zipper, making it difficult to maintain secure engagement when the package or bag is opened.
Innovation Solution
Inverted T-shaped endstops are formed on the zipper material at package-width intervals, allowing the zipper to be separated at the mid-point and providing a secure engagement by positioning the slider above the cross element of the endstop, preventing prying forces from dislodging the slider.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the zipper flanges are co-planar or attached to the outside of the zipper profiles, then the slider engagement is compromised under distending forces, but the aesthetic appearance and structural simplicity are improved
Solution Approach 1:
The patent forms inverted T-shaped endstops on the zipper material before the slider is inserted onto the zipper profile. These endstops create protrusions that extend into the slider's path, preventing the slider from being pried off by distending forces. By preparing the endstops in advance during zipper manufacturing, the design achieves both aesthetic simplicity (co-planar flanges) and reliable slider engagement without requiring complex retrofits.
2Reliability
If the zipper flanges are inwardly offset from the exterior side surfaces, then the slider engagement is secure under distending forces, but the aesthetic appearance and structural simplicity are reduced
Solution Approach 1:
The patent segments the zipper structure by adding discrete inverted T-shaped endstops at specific locations along the zipper material, rather than requiring the entire flange structure to be offset. This segmentation allows the majority of the zipper to maintain co-planar, aesthetically pleasing flanges, while only specific strategic points (the endstops) provide the mechanical engagement security. The endstops are formed by crushing and fusing the interlocking elements and flanges together at predetermined intervals.
3Ease of manufacture
If co-planar flanges are used, then the manufacturing process is simplified, but additional features (endstops) are required to maintain slider security
Solution Approach 1:
The patent merges the endstop formation process with the existing zipper manufacturing process. The inverted T-shaped endstops are created by crushing and fusing the interlocking elements and flanges together using the same heating and forming equipment already present in typical zipper production lines. This integration allows co-planar flanges to be manufactured with endstops without requiring entirely new manufacturing processes, thus maintaining ease of manufacture while adding the necessary structural complexity for slider security.
Data Source
AI summary
A length of flanged zipper material for reclosable packages or bags is provided with inverted T-shape endstops wherein the zipper profiles are crushed and the flanges are fused together. The reclosable packages or bags are separated at the mid-point of the inverted T-shaped endstops thereby forming L-shaped and reversed L-shaped endstops. The zipper flanges are fused together in the lower cross elements of the endstop thereby providing an area for the slider to be placed wherein the forces from distension of the package or bag walls are unlikely to exert forces to separate the slider from the zipper. This is particularly applicable to slider zippers wherein the flanges are attached to or substantially co-planar with the exterior sidewalls of the interlocking elements of the zipper profiles.