Threaded Thermoplastic Bolt Cap for Fast EME Isolation

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Solution Overview

Problem

Existing electrically insulated and containment caps for metallic bolt assemblies are costly and time-consuming to install due to their dependency on liquid sealant and require multiple variations in length to accommodate varying bolt shaft extensions, leading to high installation costs and potential quality control issues.

Innovation Solution

A cap assembly comprising a first cap member with threads and a second cap member with a receptacle, where the threads on the first cap member engage with the receptacle's threads, allowing for adjustable positioning to accommodate different bolt shaft lengths, reducing the need for multiple cap sizes and simplifying installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If liquid sealant is used to fill the cap, then the cap can be sealed and electrically isolated, but the installation becomes time-consuming and requires high fairing standards

Engineering Contradiction:
Improveelectrical isolationVSAvoidinstallation speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent removes the liquid sealant filling step from the cap installation process. Instead of filling the cap with liquid sealant that requires curing time and fairing, the invention uses a pre-formed cap with integrated sealing features that eliminates the need for liquid sealant application, thereby speeding up installation while maintaining electrical isolation reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sealing and electrical isolation features are pre-integrated into the cap structure during manufacturing, rather than being applied during installation. The cap is pre-formed with sealing surfaces and insulation properties, allowing for rapid installation without time-consuming sealant application and curing processes

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If a fixed length sealant cap is used, then the cap structure is simple, but it cannot accommodate varying distances from bolt threads to surface

Engineering Contradiction:
Improvecap structureVSAvoidaccommodation of varying bolt lengths
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The cap incorporates an adjustable mechanism that allows its effective length to be modified during installation. The cap can be extended or repositioned along the bolt shaft to accommodate varying distances from the threads to the surface, providing adaptability without requiring multiple fixed-length cap variants

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

A single cap design with adjustable features serves multiple functions: it provides electrical isolation, sealing, and adaptation to various bolt configurations. This universal cap replaces the need for multiple specialized cap lengths, simplifying inventory and installation while maintaining versatility

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple variations in cap length are used to accommodate varying bolt shaft extensions, then all bolt configurations can be covered, but installation costs and complexity increase

Engineering Contradiction:
Improvecoverage of bolt configurationsVSAvoidnumber of cap sizes
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single universal cap design with adjustable features replaces multiple fixed-length cap variants. This universal cap can be configured to fit various bolt shaft extensions by adjusting its position or effective length, thereby covering all bolt configurations while reducing the number of different cap sizes needed

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cap incorporates dynamic adjustment capabilities that allow it to adapt its effective length during installation. This dynamic feature enables one cap design to serve multiple length requirements, eliminating the need to maintain inventory of multiple fixed-length cap variations

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3462046B1Rapid installation thermoplastic EME protection cap
Publication Date: 2022.04.06 THE BOEING CO
  • EP3462046B1 patent drawingFigure 1
  • EP3462046B1 patent drawingFigure 2
  • EP3462046B1 patent drawingFigure 3

AI summary

A cap assembly (36) for enclosing an end portion (22) of a bolt fastener (18) includes a first cap member (38) which includes a bore (40) and a surface (42) positioned within the bore (40) which defines first threads (44) and the first cap member (38) also includes an external surface (46) which defines second threads (48). A second cap member (50) includes a sidewall (56) which defines a receptacle (58) with an opening which provides access to an interior (62) of the receptacle (58) and the sidewall (56) includes an interior surface (64) which defines third threads (66) compatibly configured to engage the second threads (48). The third threads (66) are positioned along the interior surface (64) of the receptacle (58) extending along a length of the receptacle (58) a first distance and the second threads (48) are positioned along the external surface (46) of the first cap member (38) extending along a length of the external surface (46) a second distance wherein the first distance is greater than the second distance.