Double-Wall Fastener Cap to Contain Uncured Sealant

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Solution Overview

Problem

Existing electrical insulation containment apparatuses for metallic fasteners are inefficient in preventing uncured sealant from escaping during installation, leading to labor-intensive smoothing and visual inspection processes, and potential adhesion issues.

Innovation Solution

A containment apparatus with a cap member design that includes a first and second wall member configuration, where the second wall member surrounds the first to form a second cavity, preventing uncured sealant from exiting during installation and providing additional securement when cured, thereby reducing labor and costs associated with smoothing and adhesion testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uncured sealant is used within the cap member, then the sealant can be applied and positioned, but the uncured sealant is displaced and squeezed out during installation requiring smoothing

Engineering Contradiction:
Improvesealant applicationVSAvoidsmoothing process
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The cap member is divided into two distinct cavities: a first cavity for containing the uncured sealant and a second cavity formed by a second wall member that provides additional containment. This segmentation prevents the sealant from being squeezed out during installation while maintaining ease of application.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second wall member is pre-installed on the cap member before the uncured sealant is applied to the fastener. This preliminary action creates a pre-formed containment structure that prevents sealant displacement during the subsequent installation process, eliminating the need for post-application smoothing.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If uncured sealant is contained within the cap member, then electrical insulation is provided, but the sealant may escape during installation requiring additional containment

Engineering Contradiction:
Improveelectrical insulationVSAvoidcontainment structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The second wall member is nested over the first wall member of the cap member, creating a double-walled containment structure. This nested configuration provides enhanced sealant containment and electrical insulation while maintaining a compact design that does not significantly increase overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Productivity

If the cap member is installed with uncured sealant, then the fastener is enclosed, but labor and time are required for smoothing and inspection

Engineering Contradiction:
Improveinstallation speedVSAvoidsmoothing and inspection time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The second wall member is pre-installed on the cap member before the uncured sealant is applied to the fastener. This preliminary action creates a pre-formed containment structure that prevents sealant displacement during the subsequent installation process, eliminating the need for post-application smoothing and inspection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The double-cavity containment structure is designed to automatically contain and secure the uncured sealant during installation without requiring external intervention for smoothing or additional containment measures. The structure serves itself by providing inherent sealant retention capabilities.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3650715B1EME cap for preventing uncured sealant squeeze out
Publication Date: 2024.03.06 THE BOEING CO
  • EP3650715B1 patent drawingFigure 1
  • EP3650715B1 patent drawingFigure 2
  • EP3650715B1 patent drawingFigure 3

AI summary

A containment apparatus for enclosing a metallic fastener extending through a structure includes a cap member. The cap member includes a first wall member which defines a first cavity and a first end. The first end defines a first opening providing access into the first cavity for at least a portion of the metallic fastener. The cap member further includes a second wall member secured to and extends from an exterior surface of the first wall member. The second wall member extends spaced apart from and along the first wall member to a first end. The second wall member surrounds the first wall member such that first wall member and second wall member form a second cavity positioned between the first wall member and the second wall member. The first end of the first wall member and the first end of the second wall member are coplanar with one another.