Fluid-Tight Fastener Assembly With Overmolded Watertight Sealing

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Solution Overview

Problem

Existing fastener assemblies fail to provide a watertight seal, allowing moisture to infiltrate between secured components, which is a challenge in various applications including vehicle components and other assemblies.

Innovation Solution

A fluid-tight fastener assembly is designed with a retaining clip and an overmolded rubber housing that provides a watertight interface, using a plastic retaining clip with opposed receiving legs and a deformable rubber housing to prevent liquid infiltration, featuring a central clip channel and triangular couplers for secure sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fastener assemblies are used to secure components, then the components can be easily installed and secured, but moisture can infiltrate between the components through channels and gaps in the fastener assembly

Engineering Contradiction:
Improvefluid-tight sealingVSAvoidfastener assembly structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements nesting by placing the retaining clip inside the hollow cavity of the fastener assembly, and the sealing element within the retaining clip structure. This nested arrangement allows multiple functional components to occupy the same spatial envelope, achieving fluid-tight sealing without significantly increasing the overall device complexity or external dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs a flexible sealing element that can deform to conform to the mating surfaces of the components being joined. This flexible membrane-like structure creates effective fluid-tight barriers at the interfaces, preventing moisture infiltration while maintaining a relatively simple fastener assembly design.

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a fluid-tight housing is overmolded onto the retaining clip to provide watertight interfaces, then liquid infiltration is prevented, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvewatertight interfaceVSAvoidovermolding process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent utilizes composite construction by overmolding a fluid-tight housing material onto a retaining clip made of different material properties. This composite approach integrates multiple materials with complementary characteristics into a single unified component, achieving superior watertight interfaces while consolidating assembly steps and potentially simplifying the overall manufacturing process.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a softer rubber housing is used to provide fluid-tight sealing, then sealing effectiveness is improved, but the structural strength may be reduced compared to harder plastics

Engineering Contradiction:
Improvesealing effectivenessVSAvoidhousing strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent resolves the strength-sealing contradiction by creating a composite structure where the retaining clip provides structural strength and rigidity, while the overmolded fluid-tight housing material provides sealing effectiveness. The retaining clip's harder material sustains mechanical loads, and the softer housing material conforms to surfaces to prevent fluid leakage, with each material optimized for its specific function.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by using different material properties in different regions of the fastener assembly. The retaining clip is made of stronger material for structural integrity, while the housing portion that contacts mating surfaces is made of softer material for sealing. This spatial differentiation of material properties allows each region to perform its specific function optimally without compromising overall performance.

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 fluid-tight fastener assembly effectively prevents liquid and gas from passing through, ensuring a reliable watertight seal between components, enhancing the durability and performance of the assembly by using a resilient rubber housing and a harder plastic clip for secure coupling.

Implementation Method 1

The fluid-tight housing may be formed of rubber that is softer than the plastic retaining clip

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3455509B1Fluid-tight fastener assemblies
Publication Date: 2022.09.28 ILLINOIS TOOL WORKS INC
  • EP3455509B1 patent drawingFigure 1~2
  • EP3455509B1 patent drawingFigure 3~4
  • EP3455509B1 patent drawingFigure 5~6

AI summary

A fastener assembly (100) is configured to securely couple to one or more components. The fastener assembly includes a retaining clip (104), and a fluid-tight housing (102) coupled to the retaining clip. The fluid-tight housing is configured to provide fluid-tight interfaces with the retaining clip and the one or more components.