Spark Containment Cap Jig for Single-Sided Wing Fastening

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Solution Overview

Problem

The challenge of securing fasteners to aircraft wing structures without access to the inside, particularly in one-way and single-sided assembly methods, while ensuring spark containment for safety against lightning-induced ignition hazards, necessitates precise cap positioning and drilling without disassembly.

Innovation Solution

A method involving a jig assembly with spark containment caps secured using adhesive material, where the jig is mounted on the structure, adhesive injected through ports, cured, and the jig removed, allowing fasteners to be installed through the caps, ensuring accurate positioning and safety compliance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spark containment caps are fitted prior to drilling operation to ensure safety, then protection from ignition sources is improved, but positioning accuracy and drilling precision become more difficult to achieve

Engineering Contradiction:

Improveprotection from ignition sourcesVSAvoidpositioning accuracy and drilling precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The spark containment cap is fitted to the fastener before the drilling operation, allowing the cap to be positioned accurately on the fastener tail while the fastener itself is yet to be installed. This preliminary positioning ensures both safety protection and drilling precision are achieved, as the cap is already in its final position when drilling occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fastener acts as an intermediary element that connects the spark containment cap to the structure. The cap is fitted to the fastener tail, which then guides the fastener through the drilled hole into the structure, ensuring both accurate positioning and safety protection are maintained throughout the assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If one-way assembly method is used to install fasteners from outside the wing structure, then access requirements are simplified, but positioning accuracy of fasteners becomes more difficult to achieve

Engineering Contradiction:

Improveaccess requirementsVSAvoidpositioning accuracy of fasteners

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The spark containment cap is pre-fitted to the fastener tail before insertion, establishing the precise final position of the fastener. This preliminary action ensures that when the fastener is inserted through the drilled hole from the outside, it achieves accurate positioning without requiring access to the inside of the structure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces the need for mechanical alignment and positioning from both sides of the structure with a pre-assembled unit (fastener with cap) that is guided into position by the drilled hole alone, simplifying the assembly process while maintaining precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If single sided assembly is used to perform drilling and fastening without disassembling wing skin, then disassembly operations are eliminated, but accurate positioning of cap and drilling becomes more critical

Engineering Contradiction:

Improvedisassembly operations eliminatedVSAvoidaccurate positioning of cap and drilling

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The spark containment cap is fitted to the fastener before the drilling operation, establishing the precise final position in advance. This preliminary positioning is critical in single-sided assembly where the wing skin is not removed, as it ensures both the cap and drilling are accurately positioned without requiring subsequent adjustment or disassembly operations.

Inventive Principle:

Principle #10Preliminary 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

Enables secure fastening of structures with spark containment, allowing single-sided assembly and precise drilling without disassembly, thereby ensuring safety and efficiency in fastener installation.

Implementation Method 1

securing the spark containment caps to the first structure by injecting adhesive material into contact with the first structure and the spark containment caps and then curing the adhesive material

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS12565333B2Jig for spark containment caps

Publication Date: 2026.03.03 AIRBUS OPERATIONS LTD

AI summary

A method of securing a first structure to a second structure is disclosed including providing a jig assembly having spark containment caps carried by a jig; mounting the jig assembly on a structure so that the spark containment caps and the jig contact the first structure; securing the spark containment caps to the first structure by injecting adhesive material into contact with the first structure and the spark containment caps and then curing the adhesive material; removing the jig after the adhesive material has cured; and securing the first structure to the second structure with fasteners, each fastener having a tail which is inserted through the first and second structures and into a respective one of the spark containment caps.