Fastener Securing Assembly for Captive Retention After Disassembly

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Solution Overview

Problem

Existing anti-loss devices for fastening elements require an additional assembly step to position the securing element, which is inconvenient, especially in automated assembly processes like motor vehicle manufacturing.

Innovation Solution

A securing element is pre-fixed to the second component before assembly, allowing the fastening element to engage with it without an additional assembly step, and remains captive on the fastening element when the components are disconnected, utilizing a barrier on the fastening element's shank and an elastic or adhesive securing element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a securing element is used to prevent fastening element loss, then reliability is improved, but device complexity increases due to additional assembly steps

Engineering Contradiction:
Improvefastening element retentionVSAvoidassembly process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The securing element is pre-fixed to the second component before assembly, eliminating the need for additional assembly steps during the main assembly process. The securing element is positioned in advance on the second component (40) and remains attached during the initial assembly operation, only detaching when the fastening element is removed for the first time.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If a securing element is pre-fixed to the second component, then ease of operation is improved by eliminating additional assembly steps, but manufacturing complexity increases

Engineering Contradiction:
Improveassembly operation simplicityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The securing element is integrated with the second component by pre-fixing it during the manufacturing of the second component. This merging of the securing element attachment process into the existing manufacturing workflow avoids adding separate manufacturing steps while still achieving the desired functionality.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the securing element remains on the fastening element after disassembly, then loss prevention is improved, but the fastening element cannot be reused

Engineering Contradiction:
Improvefastening element recoveryVSAvoidfastening element reusability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The securing element is designed to be discarded (remaining on the fastening element) after the first disassembly to ensure the fastening element is recovered and not lost. The securing element acts as a sacrificial component that prevents loss of the more valuable fastening element, which can then be reused on a different component.

Inventive Principle:
Principle #34Discarding and recovering

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method simplifies the assembly process by eliminating the need for an additional assembly step and ensures the fastening element is not lost during disassembly, with the securing element remaining on the fastening element, facilitating efficient and precise positioning during reassembly.

Implementation Method 1

the securing element is made of an elastic material, preferably rubber. Since elastic materials are relatively easily deformed, they are particularly well suited for forming the securing elements, since the fastening element with its shaft and the barrier arranged thereon can be inserted through a through-opening of the securing element and the barrier engages behind the securing element

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3334947B1Assembly and method for securing a fastening element
Publication Date: 2021.05.12 VOLKSWAGEN AG
  • EP3334947B1 patent drawingFigure 1
  • EP3334947B1 patent drawingFigure 2

AI summary

The invention relates to an assembly for securing a fastening element (20) to a first component (50), wherein the first component has a passage opening (52) for a shaft (24) of the fastening element, said assembly comprising a securing element (30), which reaches around the shaft of the fastening element, wherein a head part of the fastening element and the securing element are arranged on opposite sides of the first component and the shaft of the fastening element engages in a receptacle of a second component (40) for the frictional and/or interlocking connection of the two components. According to the invention, the securing element (30) is pre-fastened to the second component (40) before a first connection of the first component (50) to the second component (40) and is separated from the second component (40) and reaches around the shaft (24) of the fastening element (20) after a first release of the connection between the first component (50) and the second component (40).