Slide Fastener Gap Design for Core String Stability

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Solution Overview

Problem

In conventional slide fasteners, the core strings can slide out or get caught between the upper and lower flanges of the slider due to gaps between fastener elements, compromising the flexibility and designability of the fastener.

Innovation Solution

A slide fastener design featuring a slider with upper and lower blades, guide posts, and Y-shaped element guide passages, where the gap between flanges is smaller than the core strings, and fastener elements are independently disposed with design and engaging portions to prevent core string displacement and enhance flexibility and designability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gaps between adjacent fastener elements are broadened to arrange element rows in a linear fashion, then designability is improved, but core strings may slide out through or be caught in the gap between upper and lower flanges

Engineering Contradiction:
ImprovedesignabilityVSAvoidcore string stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the dimensional parameter of the gap between upper and lower flanges, making it smaller than the dimension of core strings when pressed. This parameter modification prevents core strings from sliding out or being caught while preserving the linear arrangement of fastener elements for designability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary anti-action by designing the flange gap dimension in advance to be smaller than the core string dimension under pressure. This preemptive dimensional constraint prevents the harmful effect of core string displacement before it can occur during use.

Inventive Principle:
Principle #9Preliminary anti-action

2Adaptability or versatility

If plate thicknesses of upper and lower flanges are reduced to allow independent disposal of fastener elements, then flexibility is improved, but structural strength may be compromised

Engineering Contradiction:
ImproveflexibilityVSAvoidflange structural strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent modifies the plate thickness parameter of the flanges to be smaller than the distance between adjacent fastener elements. This enables independent disposal of fastener elements and improves flexibility while maintaining sufficient structural strength through optimized dimensional relationships.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2705768B1Slide fastener
Publication Date: 2017.07.12 YKK CORP
  • EP2705768B1 patent drawingFigure 1
  • EP2705768B1 patent drawingFigure 2
  • EP2705768B1 patent drawingFigure 3

AI summary

There is provided a slide fastener capable of preventing core strings from being caught in a gap between upper and lower flanges, securing the flexibility of the slide fastener when engaged, and improving the designability of the slide fastener. The dimension (L4) of a gap (S3) between the upper and lower flanges (33a, 33b) of a slider (30) in the up-down direction is smaller than the dimension (L5) of the core strings (13a) in the front-rear direction when the core strings are pressed with the pressure of 5kgf. Fastener elements (15) constituting a fastener element row (14) are independently disposed in the up-down direction of a tape member (12) when engaged. The fastener element (15) has a design portion (16) disposed at a front side of the tape member (12), and an engaging portion (17) disposed at a rear side of the tape member (12) so as to engage with adjacent fastener element (15), and the design portion (16) is disposed distant from the adjacent design portion (16) when engaged and having a hemispherical shape with a curved shape.