Staggered Molded Surface Fastener for Consistent Loop Engagement

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Solution Overview

Problem

Existing molded surface fasteners with regularly aligned engaging elements suffer from inconsistent loop engagement due to varying separation distances between engaging pawl portions, leading to reduced peel strength and compatibility issues with non-woven fabrics.

Innovation Solution

A molded surface fastener design featuring engaging elements with symmetrical pawl portions disposed at symmetrical positions relative to a center line, arranged in a staggered pattern to maintain consistent separation distances between pawl portions, enhancing loop engagement and stability across different non-woven fabrics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If engaging elements are arranged in a regular aligned pattern, then manufacturing is simplified, but loop engagement consistency deteriorates due to varying separation distances between pawl portions

Engineering Contradiction:
Improvearrangement simplicityVSAvoidloop engagement consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by shifting the arrangement pattern of engaging elements between adjacent element rows. Specifically, odd-numbered element rows are shifted by half the pitch interval in the machine direction compared to even-numbered element rows. This asymmetric offset arrangement ensures that pawl portions from adjacent rows maintain consistent separation distances, resolving the contradiction between manufacturing simplicity and engagement consistency.

Inventive Principle:
Principle #4Asymmetry

2Strength

If engaging elements are arranged with consistent pawl separation distances, then peel strength is improved, but element arrangement complexity increases

Engineering Contradiction:
Improvepeel strengthVSAvoidarrangement complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent segments the element rows into odd-numbered rows and even-numbered rows with different arrangement patterns. By dividing the overall arrangement into two distinct segmented groups with systematic offsets, the patent achieves consistent pawl separation distances across all adjacent rows while maintaining a manageable level of arrangement complexity through the regular alternation pattern.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3821749B1Molded surface fastener
Publication Date: 2025.05.14 YKK CORP
  • EP3821749B1 patent drawingFigure 1
  • EP3821749B1 patent drawingFigure 2
  • EP3821749B1 patent drawingFigure 3~4

AI summary

In a molded surface fastener (1, 2, 3) in which an engaging element (10, 17, 18, 60, 70) includes at least two engaging pawl portions (13, 73) protruded outward, a plurality of the engaging elements (10, 17, 18, 60, 70) is disposed in a line along a machine direction (MD) to form an element row (15, 65, 75), a plurality of the element rows (15, 65, 75) is arranged side by side in a cross direction (CD), each of the engaging elements (10, 17, 18, 60, 70) has, as the engaging pawl portions (13, 73), at least a pair of symmetrical engaging pawl portions (13, 73) which are disposed each other at symmetrical positions in the cross direction (CD) and are respectively protruded in the cross direction (CD) sides, and a plurality of the engaging elements (10, 17, 18, 60, 70) is arranged in a staggered pattern. Thereby, the molded surface fastener (1, 2, 3) can appropriately and stably exert desired performance such as peel strength with respect to more types of non-woven fabrics.