Attachment Device With Bending Tabs For Secure Fastening

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Solution Overview

Problem

Current attachment devices have a low holding force and lack clear indication of the ideal working position, leading to increased risk of detachment during assembly, due to a low interference surface both before and after screwing.

Innovation Solution

An attachment device with a nut element, flange element, and tabs that bend inwardly during screwing, increasing the interference surface and providing a clear indication of correct assembly through noise and enhanced retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the attachment device uses a conventional structure with low interference surface, then the device complexity is reduced, but the reliability of the attachment device decreases due to increased risk of detachment

Engineering Contradiction:
Improveattachment device retentionVSAvoidattachment device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The attachment device is segmented into a nut element, flange element, and multiple tabs connecting them. This segmentation allows the tabs to independently bend and increase the interference surface area, improving retention while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The tabs are designed to bend in a radial direction perpendicular to the axial screwing motion. This dimensional change transforms the interference surface from a static small area to a dynamic expanded area, increasing contact with the bench in a radial dimension while the screwing proceeds axially.

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

2Reliability

If the attachment device has a low interference surface before screwing, then the ease of operation is improved for insertion, but the reliability decreases due to higher risk of detachment during assembly

Engineering Contradiction:
Improvedetachment riskVSAvoidassembly operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The tabs are designed as flexible elements that dynamically change shape during the assembly process. Before screwing, they maintain a configuration that facilitates insertion, then bend radially during screwing to maximize interference surface and retention, adapting to different stages of assembly.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The interference surface area parameter changes dynamically during assembly. The tabs start with a smaller effective interference surface for easy insertion, then transform to provide a larger interference surface during screwing, changing the geometric parameters to match assembly requirements at different stages.

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If the attachment device lacks clear indication of working position, then the device complexity is reduced, but the loss of information increases as the operator cannot know when correct assembly is reached

Engineering Contradiction:
Improveassembly status indicationVSAvoidindication mechanism
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The attachment device provides self-indication through the noise generated by the tabs bending against the bench during screwing. This acoustic feedback serves as a built-in indication mechanism that requires no additional components, allowing the operator to know when correct assembly is reached through the characteristic sound.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The bending of the tabs against the bench surface generates mechanical vibrations and acoustic noise that serve as feedback to the operator. This vibration-based indication system provides clear information about assembly status without adding complex electronic or mechanical indication devices.

Inventive Principle:
Principle #18Mechanical vibration

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 increased interference surface minimizes detachment risk and ensures secure assembly, with the attachment device maintaining higher retention even after screwing, accommodating various weights and tolerances.

Implementation Method 1

each tab comprises a first projection inwards the attachment device and a second projection outwards the attachment device... when the nut element is moved axially towards the flange element the tabs bend inwardly

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3995709B1Attachment device
Publication Date: 2023.08.09 CELULOSA FABRIL
  • EP3995709B1 patent drawingFigure 1
  • EP3995709B1 patent drawingFigure 2
  • EP3995709B1 patent drawingFigure 3

AI summary

The present invention relates to an improved attachment device with an increased interference surface that provides a lower risk of the attachment device detachment and a greater retention of the elements that this attachment device fixes. The present invention also relates to an assembly of an attachment device fixed to a bench.