Compression-Fit Seal Cap for Fastener Liftoff Prevention

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Solution Overview

Problem

Current EME protection seal cap installations in aircraft are time-consuming, labor-intensive, and prone to defective installations, requiring re-installation and additional labor and cost, especially in confined spaces where maintaining the seal cap during sealant decompression is challenging.

Innovation Solution

A protection seal cap with a continuous wall member that creates an interference compression fit with the fastener, allowing it to securely attach and maintain position without manual holding, even in orientations challenging gravity, and enabling sealant injection and decompression without liftoff, using a thermoplastic or thermoset material for deformation and friction retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the protection seal cap is installed using conventional methods, then the seal cap can be installed, but the installation requires manual holding during sealant decompression which increases installation time and labor

Engineering Contradiction:
Improveinstallation speedVSAvoidmanual holding requirement
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The protection seal cap is designed with a biasing configuration that automatically maintains contact between the base rim and the structure surface during sealant decompression. The cap self-regulates its position through the biased force, eliminating the need for manual holding by the installer and enabling unattended installation in confined spaces

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biasing configuration is pre-built into the cap structure before installation, providing automatic positional maintenance during the sealant decompression phase. This preliminary mechanical action ensures the cap remains properly positioned without requiring continuous manual intervention throughout the installation process

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the protection seal cap is installed in confined spaces with challenging orientations, then the seal cap can be installed in difficult-to-reach locations, but gravity makes it difficult to maintain the seal cap in the desired position during sealant decompression

Engineering Contradiction:
Improveinstallation location flexibilityVSAvoidcap position stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The biasing configuration generates a force that counteracts gravitational effects and other external forces acting on the cap during installation. This biased force actively pushes the base rim against the structure surface, maintaining stable contact and preventing cap displacement even in challenging orientations or confined spaces where gravity would otherwise cause liftoff

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Ease of manufacture

If the sealant decompression is allowed to proceed without holding the cap, then the decompression process can complete, but the cap experiences liftoff from the structure surface which requires re-installation

Engineering Contradiction:
Improveinstallation simplicityVSAvoidinstallation quality
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The biasing configuration is designed to apply a preliminary counteracting force that opposes the liftoff tendency caused by sealant decompression. This pre-built mechanical bias actively prevents cap separation from the structure surface during the entire decompression process, ensuring reliable installation quality without requiring re-installation

Inventive Principle:
Principle #9Preliminary anti-action

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 reduces installation time and defects, allows for secure positioning without manual holding, and facilitates in-service maintenance without full sealant removal, enhancing installation efficiency and quality.

Implementation Method 1

Continuous wall member 24 is configured to create an interference compression fit between end portion 12 of fastener 14 and continuous wall member 24

Methodology Applied
Scientific EffectInterference fit: Friction

Implementation Method 2

Continuous wall member 24 is configured to create an interference compression fit between end portion 12 of fastener 14 and continuous wall member 24

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

deformation and friction retention

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3882159B1Compression fit EME protection seal cap
Publication Date: 2024.09.18 THE BOEING CO
  • EP3882159B1 patent drawingFigure 1
  • EP3882159B1 patent drawingFigure 2
  • EP3882159B1 patent drawingFigure 3

AI summary

A protection seal cap for enclosing an end portion of a fastener which extends from a structure, which includes a cap member, which includes a sidewall that defines an interior space within the cap member. The sidewall forms a continuous wall member positioned within the cap member. The continuous wall member defines an opening providing access to the interior space. The continuous wall member is configured to create an interference compression fit between the end portion of the fastener and the continuous wall member.