Slide Fastener Element Inner Coupling Convex Positioning

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Solution Overview

Problem

Slide fasteners with fastener elements resembling those formed by die-casting are prone to coupling cracks when bent into a U-shape due to the positioning of coupling convex portions along outer side edges, leading to reduced flexibility and coupling disengagement.

Innovation Solution

The fastener elements are designed with coupling convex portions positioned on the inner side, apart from outer side edges, featuring a slope portion and a raised portion to enhance strength and prevent contact with the flat plate portion, along with oblique fin portions for improved attachment and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If coupling convex portions are positioned along outer side edges of the flat plate portion, then the fastener element can be formed with a simple structure, but coupling cracks occur when the slide fastener is bent into a U-shape

Engineering Contradiction:

Improvestructure of fastener elementVSAvoidcoupling state stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent inverts the conventional positioning of coupling convex portions by placing them on the inner side of the flat plate portion rather than along the outer side edges. This inversion prevents the coupling convex portions from contacting each other during bending, eliminating coupling cracks while maintaining structural simplicity

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces asymmetry in the positioning of coupling convex portions relative to the outer edges of the flat plate portion. By offsetting them inward, the design creates an asymmetric configuration that prevents direct contact between opposing fastener elements during bending, thereby preventing coupling disengagement

Inventive Principle:

Principle #4Asymmetry

2Reliability

If coupling convex portions are positioned on the inner side apart from outer side edges, then coupling cracks are prevented during bending, but the fastener element requires additional structural features like slope portions and raised portions

Engineering Contradiction:

Improvecoupling state stabilityVSAvoidstructure of fastener element

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by adding specific structural features (slope portions and raised portions) only at critical locations of the coupling convex portions. These localized features prevent contact during bending without requiring complex modifications throughout the entire fastener element structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The coupling convex portion is segmented into distinct functional regions: the slope portion that prevents initial contact, the raised portion that maintains spacing, and the coupling function area. This segmentation allows each part to perform its specific function efficiently while keeping the overall structure manageable

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If fastener elements are designed with inner-side positioning of coupling convex portions, then flexibility and bendability are improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvebendability of slide fastenerVSAvoidpositioning accuracy of coupling convex portions

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The slope portion acts as a preliminary action feature that prevents contact between coupling convex portions before the bending force becomes significant. This preliminary prevention mechanism reduces the stress on manufacturing precision by providing a buffer zone that accommodates minor positioning variations

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3556242B1Fastener element and fastener stringer

Publication Date: 2022.05.18 YKK CORP

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AI summary

Provided is a metallic fastener element including a coupling head portion (11) and a tape holding portion (21), in which the coupling head portion (11) includes a flat plate portion (12), a central projecting portion (13) projecting from an upper surface and a lower surface of the flat plate portion (12), and a right and left pair of coupling convex portions (14), and the right and left coupling convex portions (14) are disposed on an inner side in the element width direction to be apart from right and left outer side edges on the upper surface and the lower surface of the flat plate portion (12). Thereby, a fastener element (10) of a slide fastener (1) has an appearance like "Japanese kokeshi doll" and can have gloss and color which cannot be obtained by die-casting. Further, when the slide fastener (1) is bent into a U-shape in a coupling state of the fastener elements (10), an occurrence of coupling cracks can be prevented. (150 words)