Slider Pull Tab Retainer Rounded Edge Design

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Solution Overview

Problem

Existing slide fasteners with automatic lock features can damage the pull tab due to sharp edges from metal cover elements, which is undesirable for high-end sliders with expensive materials or quality finishes.

Innovation Solution

A pull tab retainer with inwardly extended tongues and rounded edges is used to accommodate the pull tab ring, providing a non-offensive contact surface and reducing friction-related damage, and can be made integrally as a single piece using a molding process, optionally with metal or non-metal materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cover element is made of metal by means of a shearing process, then manufacturing cost is reduced and mass production is enabled, but sharp edges are produced that damage the pull tab ring

Engineering Contradiction:
Improvemanufacturing processVSAvoiddamage to pull tab
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by providing rounded edges specifically at the recesses where the pull tab ring contacts the cover element, while the rest of the cover element can remain sharp-edged for manufacturing efficiency. This localized modification eliminates damage to the pull tab ring without compromising the overall manufacturing process or structural integrity of the cover element.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The rounded edges act as an intermediary feature between the metal cover element and the pull tab ring. By introducing this intermediate geometric feature, the patent mediates the harmful interaction between sharp metal edges and the pull tab ring, preventing direct damage while maintaining the metal construction of the cover element.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the cover element has recesses with sharp edges for retaining the pull tab, then the structure is simple and manufacturing is easy, but visible scratches are produced on high-end sliders

Engineering Contradiction:
Improvecover element structureVSAvoidsurface finish quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by modifying only the specific areas where the pull tab ring contacts the cover element (the recesses) with rounded edges, while leaving the rest of the cover element structure simple and unchanged. This selective modification improves surface finish quality at critical contact points without adding overall structural complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies spheroidality by replacing sharp edges with rounded edges at the recesses. This curvature modification eliminates the harmful sharp corners that cause scratches on high-end sliders, while maintaining the overall simplicity of the cover element structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of operation

If the pull tab ring is in direct contact with the side walls of the cover element, then the retention mechanism is simple, but friction causes visible damage and reduces durability

Engineering Contradiction:
Improvepull tab retentionVSAvoidpull tab integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by providing rounded edges specifically at the contact zones between the pull tab ring and the cover element's recesses. This localized feature modification maintains the simplicity of the retention mechanism while eliminating the harmful friction and scratching that occurs with sharp edges.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent converts the harmful effect of friction and sharp edges into a beneficial rounded contact surface. By intentionally rounding the edges at the recesses, the friction that would otherwise damage the pull tab ring is transformed into a smooth, non-damaging contact interface that maintains both retention and durability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP3871553B1Slider for a slide fastener
Publication Date: 2022.10.19 RIRI SA
  • EP3871553B1 patent drawingFigure 1
  • EP3871553B1 patent drawingFigure 2
  • EP3871553B1 patent drawingFigure 3

AI summary

A slider for a slide fastener comprising a slider body (2) and a pull tab (3) wherein: the slider body (2) includes a pull tab retainer (11) having a first side wall (13) and a second side wall (14) with respective recesses (15, 16) for accommodation of the ring (9) of the pull tab, and each recess has a tongue (17, 18) which is inwardly extended to provide a contact surface (19, 20) for the ring, and each tongue joins with the respective side wall with a rounded edge (21, 22).