Tube Strap Fastener Assembly With Visual Installation Locking

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Solution Overview

Problem

Existing fastening techniques for automotive components are prone to incorrect installation, leading to detachment or damage of secured objects, and require heavy tools and metal bolts, making them inefficient and complex.

Innovation Solution

A fastener assembly with an installation indicator and a lightweight, all-plastic design that allows for no-tool assembly, featuring a lock pin with a shank and head, and a base structure with resilient legs and a grommet opening, ensuring proper installation verification through a vision system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional metal bolts and heavy tools are used for fastening, then the connection strength and reliability are improved, but the device weight and complexity increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidfastening system weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces traditional metal bolts and heavy mechanical fastening tools with a plastic fastener assembly that uses elastic deformation and geometric interlocking mechanisms. The resilient legs bend during insertion and lock into place through elastic recovery, eliminating the need for heavy metal components and complex mechanical tools while maintaining connection reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fastener assembly uses engineered plastic materials that combine strength, flexibility, and weight reduction properties. The resilient legs are made from plastic material that exhibits elastic behavior, allowing the fastener to be both lightweight and mechanically reliable during installation and operation.

Inventive Principle:
Principle #40Composite materials

2Reliability

If traditional fastening methods are used, then the connection strength is improved, but the ease of assembly and manufacturing complexity worsen

Engineering Contradiction:
Improvefastening reliabilityVSAvoidassembly simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fastener assembly is designed to be self-installing through a snap-in mechanism where the resilient legs automatically engage with the mounting surface during insertion. The installation indicator provides self-verification of proper installation without requiring additional tools or complex assembly procedures, making the process both reliable and simple.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The fastener is divided into distinct functional components: resilient legs for mounting, installation indicator for verification, and connection elements for securing objects. This segmentation allows each component to be optimized for its specific function while simplifying the overall assembly process through modular design.

Inventive Principle:
Principle #1Segmentation

3Reliability

If installation verification is added to ensure proper fastening, then the installation reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveinstallation verificationVSAvoidfastener structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The installation indicator uses visual color or position changes to indicate proper installation status. When the resilient legs are correctly positioned and the fastener is properly installed, the indicator displays a specific visual state that can be easily observed, providing verification without adding mechanical complexity.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

Instead of using complex mechanical verification systems, the patent employs a visual installation indicator that leverages the natural elastic deformation of the resilient legs. The indicator's position or appearance changes automatically based on the installation state, providing verification through optical rather than mechanical means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution provides reliable and efficient assembly of automotive components by ensuring proper installation, reducing weight and complexity, and enabling easy verification of installation using vision systems, thus enhancing operational efficiency.

Implementation Method 1

a base structure having a grommet portion that defines a grommet opening and a pair of legs resiliently coupled to the grommet portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least one wing portion coupled to the fixed planar portion via a hinge

Methodology Applied
Scientific EffectHinge mechanism: Hinge

Data Source

PatentEP4509745A1Fastener assembly
Publication Date: 2025.02.19 ILLINOIS TOOL WORKS INC
  • EP4509745A1 patent drawingFigure 1a~1b
  • EP4509745A1 patent drawingFigure 1c~1d
  • EP4509745A1 patent drawingFigure 1e~1f

AI summary

Described is a fastener assembly (102) for coupling a tube (110) via a strap (140) to an opening (106) formed in a component (104). The fastener assembly includes a lock pin (108) having a shank (152) with a head (128) and a base structure (116) having a grommet portion (136). The shank includes a lock tab (160). The head includes a fixed planar portion (128b) coupled to the shank and at least one wing portion (128a) coupled to the fixed planar portion via a hinge (156). The head includes an installation indicator (126) positioned over at least a portion of each of the fixed planar portion and at least one wing portion. The grommet portion defines a grommet opening (138) and a pair of legs (150) resiliently coupled to the grommet portion and configured to couple with the opening. The grommet opening is configured to receive and secure at least a portion of the shank. A first leg of the pair of legs includes a flex leg feature (146) formed therein and resiliently coupled thereto, the flex leg feature defining a positioning edge (164). The lock tab engages with the positioning edge to secure the lock pin relative to the base structure in a part-in-assembly (PIA) position.