U-Shaped Retaining Clip With Anti-Torsion Ribs

Solution Overview

Problem

Existing fastening devices for assembling vehicle door trim panels to internal walls lack sufficient resistance to tearing during side impacts and are not easily reusable or remountable, with issues such as premature release of retaining pins and potential loss during handling.

Innovation Solution

A fastening device featuring a U-shaped retaining means with anti-torsion ribs and serrations that prevent twisting during traction, allowing for secure engagement and easy disengagement, and a dual U-shaped design for secure locking and quick repositioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bent wire pin with flexible portions is used as retaining means, then the fastening device can be removed and repositioned, but the flexible portions may twist under lateral impact pressure causing unexpected release of the male element

Engineering Contradiction:

Improveremovability and repositionability of retaining meansVSAvoidresistance to torsion under lateral impact

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The retaining means is segmented into multiple functional zones: flexible portions for engagement/removal operations, and rigid anti-torsion portions with ribs for impact resistance. This segmentation allows each zone to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The retaining means combines materials or structural characteristics of both flexibility and rigidity within a single component. The composite structure includes flexible portions made of elastomeric material and rigid anti-torsion portions with reinforcing ribs, creating a unified component that exhibits both compliant and stiff behaviors as needed.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the retaining means is made completely rigid to prevent torsion, then resistance to lateral impact improves, but the ability to easily remove and reposition the retaining means is reduced

Engineering Contradiction:

Improveresistance to torsion under lateral impactVSAvoidremovability and repositionability of retaining means

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The retaining means is segmented into multiple functional zones: flexible portions for engagement/removal operations, and rigid anti-torsion portions with ribs for impact resistance. This segmentation allows each zone to optimize its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The retaining means combines materials or structural characteristics of both flexibility and rigidity within a single component. The composite structure includes flexible portions made of elastomeric material and rigid anti-torsion portions with reinforcing ribs, creating a unified component that exhibits both compliant and stiff behaviors as needed.

Inventive Principle:

Principle #40Composite materials

3Ease of operation

If a control mechanism with a protruding loop is used to extract the pin, then the pin can be removed for repositioning, but the pin may be lost during handling and the process is not very practical

Engineering Contradiction:

Improveextractability of retaining means for repositioningVSAvoidpotential loss of pin during handling

Core Design Contradiction:

Ease of operationVSLoss of substance

Solution Approach 1:

The anti-torsion ribs are merged with the retaining means as an integrated feature rather than a separate component. This merging ensures the ribs remain attached to the retaining means during extraction and repositioning operations, eliminating the risk of loss while maintaining the extractability function.

Inventive Principle:

Principle #5Merging (Combining)

4Device complexity

If the U-shaped clip arms are allowed to twist during traction, then the design remains simple and flexible, but the pull-out resistance during side impact is insufficient

Engineering Contradiction:

Improvesimplicity of U-shaped clip designVSAvoidpull-out resistance during side impact

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The anti-torsion ribs are positioned locally at critical zones of the retaining means where torsional stresses occur during lateral impact. This local reinforcement provides maximum strength where needed while maintaining simplicity in other areas of the design.

Inventive Principle:

Principle #3Local quality

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 device provides enhanced resistance to tearing forces during side impacts and ensures easy, quick, and secure assembly and disassembly, maintaining captivation of the retaining means to prevent loss.

Implementation Method 1

at least one first rib that protrudes along the axial direction from the arms of the U inside the cavity and that abuts against the inner tubular surface of the cavity to prevent the arms of the U from twisting during this traction

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The arms of the U of the retaining means form serrations which project towards the inside of the U to pinch the male element when it is inserted into the cavity of the female element

Methodology Applied

Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP3314133B1Fastening device with high pull-out strength

Publication Date: 2020.02.12 A RAYMOND & CO SCS

Figure 1~3
Figure 4A~6C
Figure 7~13

AI summary

A fastening device (1) for joining a first part to a second part comprises a female element (2) having an axial cavity (6) that has a tubular inner surface and is intended to be brought into engagement with the first part, a male element (3) in the form of a stem that is inserted axially into the cavity (6) and is intended to be brought into engagement with the second part, and a retaining means (4) in the form of a U-shaped clip which is inserted into a housing (5) of the female element (2), passing transversely through the axial cavity (6), so as to pinch the male element (3) and lock it in axial position in the cavity (6) of the female element (2), the retaining means (4) being provided with anti-twist means for the U in the event that the male element (3) is pulled out of the female element (2).