Retaining Hook Mechanism for Vehicle Trim Ejection Prevention

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Solution Overview

Problem

The deployment of an airbag in a motor vehicle can cause significant force that breaks snap-fastening elements, leading to the ejection of central facades from the dashboard, necessitating a reliable and simple means to retain the appearance member.

Innovation Solution

Incorporating retaining hooks with lugs and stoppers that extend from the appearance member, which align with corresponding orifices on the dashboard, allowing the hooks to move between positions to ensure secure attachment and retention even if snap-fastening elements break.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If snap-fastening elements are used to attach the appearance member to the trim element, then the assembly is simple and easy to manufacture, but the reliability is insufficient because the snap-fastening elements can break under airbag deployment force

Engineering Contradiction:
Improveretention reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The attachment system is divided into two independent functional segments: snap-fastening elements for normal attachment and retaining hooks for emergency retention. This segmentation allows each component to be optimized for its specific function while working together as a complete system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The retaining hooks are pre-positioned and pre-configured in the trim element before assembly, creating a backup retention mechanism that is ready to activate if the primary snap-fastening elements fail during airbag deployment.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If retaining hooks are added to prevent ejection, then the reliability improves, but the device complexity increases

Engineering Contradiction:
Improveretention reliabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The retaining hooks and snap-fastening elements are integrated into a single attachment system with coordinated orifices, allowing both retention functions to be implemented through a unified assembly process rather than separate manufacturing steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The retaining hooks are designed to automatically engage with the trim element through the second orifices and abutment zones without requiring additional fastening operations or complex installation procedures.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If the snap-fastening elements are positioned next to the first orifices, then the assembly is compact, but the retaining hooks cannot effectively retain the appearance member when snap elements break

Engineering Contradiction:
Improveattachment stabilityVSAvoiddismantling ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The retaining hooks extend in a direction perpendicular to the plane of the snap-fastening elements, utilizing the third dimension to provide retention force through the abutment zones, thereby avoiding interference with the snap element positioning.

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

Data Source

PatentEP2651684B1System for assembling a decorative member onto a vehicle trim element
Publication Date: 2015.02.11 FAURECIA INTERIEUR IND
  • EP2651684B1 patent drawingFigure 1~2
  • EP2651684B1 patent drawingFigure 3~5

AI summary

According to the invention, the decorative member (10) comprises at least one snap-fitting element (16), and the trim element (12) has at least one first opening (18) matching said snap-fitting element (16). The decorative part (10) comprises at least one retaining hook (22), including a tab (24) provided with an abutment (26), and the dashboard (12) has at least one second opening (28) enabling the abutment (26) to pass through the trim element (12). The second opening (28) is suitable for enabling a movement of the retaining hook (22) between a first position, in which the abutment (26) is opposite said second opening (28), and a second position in which the abutment (26) is opposite an abutment area (30) provided on the trim element (12). The snap-fitting element (16) is opposite a first opening (18) only when the retaining hook (22) is in the second position thereof.