Seal Cap Form for Precise Fastener Sealing Without Slumping

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Solution Overview

Problem

Conventional seal caps for fasteners in fuel receptacles, such as those in aircraft, face challenges in meeting critical dimensional requirements due to slumping of uncured sealant and require time-consuming installation and inspection processes, often necessitating rework.

Innovation Solution

A form comprising non-metallic solidified material with distal and proximal axial openings and a lateral wall with through openings is used to guide and constrain viscous sealant, ensuring consistent coverage and desired configuration, allowing the form to be abandoned after seal formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If seal caps are formed by manually discharging viscous curable sealant over each fastener, then the process is simple, but the seal caps do not meet critical dimensional requirements due to slumping of uncured sealant

Engineering Contradiction:
Improvesimplicity of seal cap formation processVSAvoiddimensional requirements of seal caps
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A form made of non-metallic solidified material is introduced as an intermediary device to shape the viscous sealant during curing. The form acts as a mold that guides and constrains the sealant to achieve precise dimensional requirements while maintaining manufacturing simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state parameters of the sealant by controlling its curing process within the form. The sealant transitions from a viscous state (prone to slumping) to a solidified state (maintaining dimensional precision) through controlled curing within the confining form

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If seal caps utilize a pre-cured exterior shell, then dimensional precision is improved, but installation time increases due to multiple time-consuming steps

Engineering Contradiction:
Improvedimensional precision of seal capsVSAvoidmanufacturing cycle time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The form is prepared in advance and placed about the fastener before sealant application. This preliminary positioning of the form eliminates the need for time-consuming post-application adjustments, smoothing, and inspection that were required with pre-cured shells

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The form is abandoned in place after seal formation, eliminating the need for removal and extensive inspection. This disposable approach to the forming device significantly reduces manufacturing cycle time compared to reusable pre-cured shells that require careful handling and inspection

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If conventional seal caps are installed using pre-cured shells with viscous sealant, then sealing function is achieved, but rework is necessary due to squeezed-out sealant and entrapped air

Engineering Contradiction:
Improvesealing functionVSAvoidcomplexity of installation process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The form serves as a mediator that controls sealant flow and prevents defects. By confining the sealant within the form boundaries during curing, the form prevents squeezed-out sealant and eliminates entrapped air, ensuring reliable sealing without complex installation procedures

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The form controls the physical parameters of the sealant during curing, maintaining proper viscosity and flow characteristics until the sealant sets. This controlled environment prevents the sealant from squeezing out and eliminates air entrapment, achieving reliable seals with simple installation

Inventive Principle:
Principle #35Parameter changes

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 method simplifies the seal formation process, reduces manufacturing cycle time, and ensures accurate sealing without the need for extensive rework, thereby improving efficiency and cost-effectiveness in sealing fasteners within fuel receptacles.

Implementation Method 1

supporting a volume of a viscous substance encapsulating at least a portion of an object, protruding through a substrate, while the viscous substance solidifies to form a seal

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3431784B1Apparatuses and methods for seal cap installation
Publication Date: 2022.04.27 THE BOEING CO
  • EP3431784B1 patent drawingFigure 1
  • EP3431784B1 patent drawingFigure 2
  • EP3431784B1 patent drawingFigure 3~4

AI summary

One example of the present disclosure relates to a form (100) for supporting a volume of a viscous substance encapsulating at least a portion (107) of an object (12) while the viscous substance solidifies to form a seal (10). The form (100) comprises a non-metallic solidified material (102); a distal axial opening (104); a proximal axial opening (106); and a lateral wall (108) between the distal axial opening (104) and the proximal axial opening (106). The lateral wall (108) comprises an outwardly facing surface (111) having a surface area, and at least one through lateral opening (110). (Fig. 1)