Foldable-Leg Rivet Fastener Assembly for Variable Hole Fit

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Solution Overview

Problem

Existing fastener assemblies require modification of components to fit specific hole sizes, are not easily removable without damaging finishes, and lose retention strength when loaded off-center, limiting their versatility and ease of use in vehicle manufacturing.

Innovation Solution

A rivet fastener assembly with a grommet and column design that includes foldable component-engaging and reinforcing legs, a pin for secure clamping, and features like tear slots for easy removal, allowing adaptation to various hole sizes and shapes without specialized tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a known plastic rivet style fastener is used, then the fastener can secure components together, but the hole must be modified to a particular size to accommodate the fastener

Engineering Contradiction:

Improveease of installationVSAvoidhole size compatibility

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The fastener body is designed with a flexible column containing multiple foldable legs that can adapt to different hole sizes and shapes. The legs are configured to fold outward upon installation, allowing the fastener to accommodate various dimensional parameters without requiring precise hole modification.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The fastener transitions from a compact linear state during insertion to an expanded folded state during operation. This dynamic transformation allows the fastener to adapt its shape and size to fit different hole configurations while maintaining secure engagement with the workpiece.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If a known single lock plastic rivet style fastener is used, then the fastener can be installed, but it loses retention strength as a load moves away from the centerline of the fastener

Engineering Contradiction:

Improveinstallation simplicityVSAvoidretention strength

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The fastener is divided into multiple independent locking legs (first set and second set) that are distributed around the central axis. This segmentation allows different legs to engage with different portions of the workpiece, distributing the load across multiple contact points rather than concentrating it at a single centerline location.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The locking legs are positioned asymmetrically around the column, with different legs extending in different directions. This asymmetric arrangement enables the fastener to handle loads from various orientations and directions, maintaining retention strength regardless of where the load is applied relative to the centerline.

Inventive Principle:

Principle #4Asymmetry

3Ease of repair

If a known rivet style fastener is removed from a component, then the fastener can be serviced, but removal risks damaging paint on exterior applications and finished surfaces

Engineering Contradiction:

ImproveserviceabilityVSAvoidsurface damage

Core Design Contradiction:

Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The fastener includes a self-removal mechanism where the pin can be extracted from the fastener body, causing the folded legs to automatically return to their linear configuration. This self-service design allows the fastener to be removed without requiring specialized tools or forceful extraction that could damage surrounding surfaces.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Instead of forcing the fastener out from the workpiece, the removal process is inverted by first detaching the pin from the fastener body, which then allows the fastener to be easily pulled out. This reverse approach prevents damage to paint and finished surfaces by avoiding direct forceful extraction of the fastener itself.

Inventive Principle:

Principle #13The other way round (Inversion)

4Adaptability or versatility

If a rivet fastener assembly with foldable legs is used, then the fastener can adapt to various hole sizes, but the structure becomes more complex

Engineering Contradiction:

Improvehole size compatibilityVSAvoidfastener structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The multiple locking legs are nested within the column structure in a compact linear arrangement during storage and installation. This nesting allows the complex multi-legged structure to be contained within a simple cylindrical form factor, reducing apparent complexity while maintaining the adaptive capability when the legs are deployed.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS11125261B2Rivet fastener assemblies

Publication Date: 2021.09.21 ILLINOIS TOOL WORKS INC

AI summary

A rivet fastener assembly is configured to securely clamp onto one or more components. The rivet fastener assembly includes a grommet including a collar and a column extending from the collar. A passage is defined through the collar and the column. The column includes component-engaging legs that are configured to fold and directly contact the component(s) when folded, and reinforcing legs that are configured to fold and reinforce the component-engaging legs when folded as the component-engaging legs directly contact the components).