Cage Nut Fastening with Elastic Fixing and Sealing Against Rattle

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Solution Overview

Problem

Existing fastening arrangements using cage nuts in sheet metal applications face issues with rattling noise due to unused nuts and leakage during surface treatments, as they lack effective fixation and sealing mechanisms, especially in motor vehicle construction where components may not always be connected.

Innovation Solution

A fastening arrangement that incorporates a fixing element with an elastic region and a sealing area to securely hold the nut in place, preventing rotation and ensuring a seal between the nut and the sheet metal or reinforcing plate, thereby eliminating rattling noise and preventing liquid penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a cage nut is used to fasten components to sheet metal, then tolerance compensation is possible and the nut can be hidden in cavities, but the nut moves within the cage when not in use causing rattling noises

Engineering Contradiction:
Improvetolerance compensationVSAvoidrattling noise
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

A fixing element is pre-installed in the cage to hold the nut in a predetermined position. This preliminary fixation prevents the nut from moving and causing rattling noises when not in use, while still allowing the nut to be removed and repositioned when fastening operations are needed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The fixing element acts as an intermediary between the cage and the nut, providing a controlled connection that prevents unwanted movement while allowing intentional repositioning. This mediator enables both stability during storage and mobility during assembly operations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If openings are created in sheet metal for fastening arrangements, then components can be connected, but liquids can penetrate through these openings during surface treatments

Engineering Contradiction:
Improvecomponent connectionVSAvoidliquid penetration
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A flexible sealing element is introduced that can adapt to the opening geometry and create a liquid-tight barrier. This sealing film or shell prevents liquid penetration during surface treatments while allowing the fastening arrangement to function when needed

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing element is pre-installed to prevent liquid penetration before the harmful effect (liquid exposure during painting/cavity sealing) occurs. This preliminary protective measure blocks the pathway for liquid infiltration while maintaining fastening capability

Inventive Principle:
Principle #9Preliminary anti-action

3Stability of the object's composition

If plastic elements are used to frictionally secure the nut in the cage, then the nut is held at a distance from sheet metal, but anti-rotation protection is only partially guaranteed

Engineering Contradiction:
Improvenut positioningVSAvoidanti-rotation protection
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The fixing element is segmented into multiple engagement features including radial projections that interact with the cage and axial features that interact with the nut. This segmentation provides both positioning stability and reliable anti-rotation protection through distributed contact points

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The fixing element combines features of rigid structural support with friction-based holding mechanisms. The composite design integrates both mechanical interlocking and frictional engagement to provide comprehensive nut securing with reliable anti-rotation protection

Inventive Principle:
Principle #40Composite materials

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

The solution provides effective rattle protection and sealing, allowing for the use of standardized cage nuts while ensuring that the fastening arrangement remains secure and leak-proof, even when not in use, and can be easily assembled and disassembled as needed.

Implementation Method 1

The fixing element has at least one elastic region which extends away from a central region of the fixing element and is supported on the cage with an elastic preload

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4012204B1Fastening arrangement and use of a fastening arrangement
Publication Date: 2024.05.22 VOLKSWAGEN AG
  • EP4012204B1 patent drawingFigure 1~2
  • EP4012204B1 patent drawingFigure 3~4
  • EP4012204B1 patent drawingFigure 5~6

AI summary

The invention relates to a fastening arrangement comprising a sheet metal plate and a cage nut, wherein the cage nut has a cage and a nut that is rotationally secured within the cage, the cage being attached to the sheet metal plate in such a way that a screw can be screwed into the nut through an opening in the sheet metal plate. The fastening arrangement includes a fixing element for fixing the position of the nut in the cage, by which the nut is subjected to a force directed towards the sheet metal plate, thereby pressing the nut against the sheet metal plate and/or a reinforcing plate of the cage nut.