Fastener Stringer Warp Thread Segmentation for Tape Surface Flatness
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Solution Overview
Problem
Fastener stringers with coil-shaped elements experience recess formation on the tape surface due to lateral-pulling-force, especially when engaging heads are arranged at a small pitch interval, leading to potential larger recesses and design issues.
Innovation Solution
A fastener stringer design featuring a fastener tape with specific patterns of warp threads that cross over the coil-shaped element's legs and weft threads, with exposed portions on the second tape-surface, preventing the weft thread from being drawn excessively to the first tape-surface, thus avoiding recess formation while maintaining a small-pitch arrangement of engaging heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engaging heads of coil-shaped element are arranged at small pitch interval, then the endurance against lateral-pulling-force is improved, but recesses are formed on the tape surface opposite to the coil-shaped element
Solution Approach 1:
The tightening threads are divided into multiple groups (first group with N threads, second group with M threads, third group with R threads) that sequentially engage different sections of the coil-shaped element. This segmentation allows the lateral-pulling-force to be distributed across multiple thread groups, preventing excessive force concentration that would cause recess formation on the tape surface.
Solution Approach 2:
Different groups of tightening threads are configured with different numbers of threads (N, M, R) to create localized variations in tightening characteristics. The first group provides initial tightening, the second group reinforces it, and the third group provides final securing. This local quality variation allows optimal force distribution across the tape surface while maintaining small pitch intervals for high endurance.
2Strength
If engaging heads are arranged at small pitch interval, then the fastener stringer achieves better mechanical performance, but non-negligible recesses are formed on the tape surface
Solution Approach 1:
The tightening threads are segmented into multiple groups that sequentially engage the coil-shaped element at different positions along the fastener tape. This segmentation distributes the mechanical load across multiple thread groups, allowing small pitch intervals for high strength while preventing excessive force concentration that would create surface recesses.
Solution Approach 2:
The tightening threads extend in a direction substantially perpendicular to the longitudinal direction of the fastener tape, creating a dimensional arrangement where threads from different groups engage at different depths and positions. This multi-dimensional arrangement allows dense engaging head spacing for strength while distributing force to maintain surface flatness.
3Force
If multiple tightening threads engage the weft thread between coil-shaped element legs, then the fastener stringer achieves better tightening, but larger recesses are formed on the tape surface
Solution Approach 1:
The tightening threads are divided into multiple groups that sequentially engage the coil-shaped element rather than all threads engaging simultaneously. This segmentation distributes the tightening force application across different spatial locations and time sequences, achieving cumulative tightening force while preventing excessive localized force that would create large surface recesses.
Solution Approach 2:
The first group of tightening threads performs preliminary tightening of the coil-shaped element, followed by the second group providing reinforcement, and the third group providing final securing. This preliminary action sequence allows progressive force application that achieves strong tightening while distributing the mechanical impact to prevent large recess formation on the tape surface.
Data Source
AI summary
A plurality of warp threads includes total N adjacent tightening threads each repeats crossing over N second legs at a side of the first tape-surface and crossing over the weft thread at a side of the second tape-surface so as to tighten the coil-shaped element to the weft thread. Said N indicates a natural number equal to or greater than 2. Each tightening thread includes an exposed portion that crosses over the weft thread and is exposed at a side of the second tape-surface. As the N adjacent tightening threads extend, the respective exposed portions of the tightening threads appear at a side of the second tape-surface one-by-one alternately or one-by-one sequentially.