Thin Hollow Element Clip Assembly With Hidden Expanding Fixation

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Solution Overview

Problem

Existing assembly methods for parts on thin hollow elements are not invisible from the outside and do not effectively utilize the hollow structure for a secure and simple fixation, particularly in motor vehicle applications where space constraints are a challenge.

Innovation Solution

A cylindrical protuberance made of flexible material with a recess for a rigid clipping pin that engages partially and then fully, causing radial expansion for secure attachment to the hollow element's edge, allowing for a hidden and secure assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional assembly methods are used for parts on thin hollow elements, then the fixation is visible from the outside, but the invention achieves invisible fixation by using a pin that expands a flexible protuberance within the hollow structure

Engineering Contradiction:
Improvevisibility of fixationVSAvoidsecure attachment
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The pin is nested within the hollow element, with the protuberance containing the pin and the head of the pin being received within the hollow structure. The pin expands the protuberance from within, creating a secure attachment that is invisible from the outside while maintaining reliable fixation.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The protuberance is made of flexible material that can be radially expanded by the pin. This flexibility allows the protuberance to deform and lock onto the inner surface of the hollow element, creating a secure invisible attachment that accommodates the rigid pin while maintaining aesthetic appearance.

Inventive Principle:
Principle #30Flexible shells and thin films

2Strength

If a rigid pin is used to secure the part, then strong fixation is achieved, but the pin cannot be inserted through the thin hollow structure without damaging it

Engineering Contradiction:
Improvefixation strengthVSAvoiddamage to hollow structure
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The pin changes its effective parameters by expanding the flexible protuberance radially. The pin itself remains rigid and maintains its dimensional stability, while the protuberance changes shape to accommodate the pin and provide secure fixation without the pin needing to force its way through the thin hollow structure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The flexible protuberance acts as an intermediary between the rigid pin and the thin hollow structure. It allows the rigid pin to be inserted and secured while protecting the hollow structure from direct contact and potential damage by the rigid pin, distributing the mechanical stress through its flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the pin is completely engaged in the recess, then secure attachment is achieved, but the protuberance must be compressed radially which requires significant force

Engineering Contradiction:
Improveattachment reliabilityVSAvoidcompression force required
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The system transitions from a static insertion process to a dynamic expansion process. The pin is inserted easily, then the protuberance dynamically expands radially to lock onto the hollow structure. This dynamic approach allows the attachment to be secured with less initial force compared to compressing a rigid structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The protuberance changes its radial parameters by expanding outward to engage with the hollow structure. This parameter change from a compressed state to an expanded state allows the attachment to be secured with less force, as the expansion is driven by the pin insertion rather than external compression.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a simple, invisible, and secure attachment method that leverages the hollow structure, ensuring reliable fixation without visible mounting means, while allowing for easy placement and sealing of parts, such as protective elements on motor vehicle doors.

Implementation Method 1

the complete engagement of the pin in the recess causing a radial expansion of the excrescence ensuring its attachment to the edge peripheral to the orifice of the first wall

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3875788B1Assembly of a part on a thin hollow element
Publication Date: 2022.08.10 RENAULT SA
  • EP3875788B1 patent drawingFigure 1~2
  • EP3875788B1 patent drawingFigure 3~4
  • EP3875788B1 patent drawingFigure 5~6

AI summary

The invention relates to an assembly of a part (1) on a hollow element (2), the latter comprising a first wall (21) and a second wall (22) substantially parallel, characterized in that the part (1) comprises at least one cylindrical protrusion (11) made of flexible material, enclosing a recess (12) for receiving a clipping pin (3), the pin (3) being made of a material rigid relative to the flexible material of the protrusion (11), the assembly being transformable between, on the one hand, an initial configuration in which the protrusion (11) and the pin (3) partially engaged in the recess (12) are inserted into an orifice (211) of the first wall (21) and, on the other hand, a final configuration in which the pin (3) is completely engaged in the recess (211) under the influence of the thrust exerted by the second wall (22) on the pin (3) during the insertion of the protrusion (11) into the orifice (211),the complete engagement of the pin (3) in the recess (12) causing a radial expansion of the protrusion (11) ensuring its attachment to the peripheral edge (212) of the orifice (211) of the first wall (21).