Elastic Locking Fastener for Reverse-Movement Resistance

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Solution Overview

Problem

Existing fastening arrangements are not secure against movement in the disengaging direction, making them unsuitable for applications with alternating forces, despite being easy to fit and tool-free.

Innovation Solution

A locking surface at the rear side of the wall portion engages with the locking protrusions to prevent reverse movement, using a locking recess or thickened regions for secure fastening, which can be integral or a separate connection unit, ensuring the article remains locked against disengagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If locking protrusions engage only with inner corner regions of the aperture, then the fastening arrangement is easy to fit without tools, but the article can be easily disengaged by moving across the clear space

Engineering Contradiction:
Improveease of fittingVSAvoidsecurity against disengagement
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The aperture is divided into distinct functional zones: a first end region for initial protrusion engagement, a clear space for movement, and a second end region with locking surface for final secure engagement. This segmentation allows the fastening process to occur in stages, improving both ease of fitting and security.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first locking protrusion engages with the inner corner region before the article is fully inserted, providing preliminary anchoring that guides the second protrusion through the clear space. This preliminary engagement makes the fitting process easier while setting up the conditions for secure final engagement.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If locking protrusions are positioned to engage with inner corner regions, then tool-free installation is achieved, but the arrangement cannot withstand large alternating forces in opposite directions

Engineering Contradiction:
Improvetool-free installationVSAvoidresistance to alternating forces
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The locking mechanism transitions from a single-point engagement at the inner corner to a distributed engagement along the aperture length. The locking surface at the second end provides engagement in a different spatial dimension, creating a more robust connection that can resist alternating forces while maintaining the simple tool-free installation process.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Area of stationary object

If the locking surface is arranged on a thickened region, then sufficient locking surface area is provided, but the wall portion thickness must be increased

Engineering Contradiction:
Improvelocking surface areaVSAvoidwall portion thickness
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The wall portion is segmented into regions with different thicknesses: a thinner main body and a localized thickened region at the second end. This segmentation provides sufficient locking surface area only where needed, minimizing the overall thickness increase while ensuring adequate engagement area for the locking protrusion.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If the locking surface is arranged on a separate connection unit, then adaptability to flexible materials is improved, but the device complexity increases

Engineering Contradiction:
Improveadaptability to flexible materialsVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A separate connection unit acts as an intermediary between the wall portion and the article. This intermediary component can be attached to flexible or curved surfaces where integral locking surfaces would not work, providing the necessary locking functionality while adapting to various material types and surface geometries.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2321541B1Fastening arrangement
Publication Date: 2013.10.02 SCANIA CV AB
  • EP2321541B1 patent drawingFigure 1A~1B
  • EP2321541B1 patent drawingFigure 2A~2D
  • EP2321541B1 patent drawingFigure 3A~4

AI summary

Fastening arrangement comprising an aperture (12) delineated in a wall portion (10) and an article (30) adapted to being connected to the aperture by elastic locking protrusions (44, 46) of the article which are directed away from one another and engage with a rear side of the wall portion, and a clear space of the aperture for allowing first the introduction of a first (44) of the locking protrusions through the aperture (12) at a first end of the aperture and thereafter the introduction of the second locking protrusion (46) through the clear space (s) at an opposite second end of the aperture. According to the invention a locking surface (14') at the rear side of the wall portion (10) is adapted to engaging with the first locking protrusion (44) and to preventing reverse movement of the article when the article has been moved along the aperture (12) across the clear space for engagement of the second locking protrusion (46) at the rear side of the wall portion (10).