Lightning-Resistant Fastener With Elastic Deformable Cap
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Solution Overview
Problem
Existing lightning-resistant fastener systems for aircraft wings face challenges in ensuring consistent insulation performance due to manual installation complexities, variability in worker quality, and potential gaps between the cap and fastener member, leading to unreliable lightning protection, especially when ambient temperatures fluctuate or the wing surface is inclined.
Innovation Solution
A lightning-resistant fastener system featuring a conductive fastener member with an engaging part and an insulating cap having an elastically deformable section, allowing the cap to conform to the fastener member's orientation and providing a sealable interface, along with a recessed installation design to prevent arc discharge leakage, ensuring reliable insulation and secure mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cap is installed separately from the fastener main body with an air-gap to provide insulation, then lightning-resistant performance is improved, but the installation position depends on worker skill and misalignment occurs
Solution Approach 1:
The cap and fastener main body are merged into a single integrated component. The cap is formed as an integral part of the fastener main body, eliminating the need for separate installation and ensuring precise positioning without relying on worker skill.
Solution Approach 2:
The air-gap structure is pre-formed during the manufacturing of the integrated fastener, before installation. The cap includes a predetermined gap structure that automatically maintains the insulation distance when installed, eliminating positioning errors.
2Reliability
If adhesive or rubber coating is applied to ensure cap insulation, then lightning-resistant performance is improved, but work time and labor increase significantly
Solution Approach 1:
The insulation function is extracted from the installation process and built into the cap structure itself. The integrated cap design includes built-in insulation features, eliminating the need for separate adhesive application or rubber coating steps.
Solution Approach 2:
The cap structure provides its own insulation function through the integrated air-gap design. The structure is self-sufficient and does not require external materials like adhesive or rubber coating to achieve lightning-resistant performance.
3Reliability
If manual bonding or rubber coating work is performed in narrow wing interior spaces, then insulation is achieved, but workability deteriorates and quality varies
Solution Approach 1:
The integrated cap structure automatically maintains proper insulation positioning and contact pressure without requiring manual adjustment. The elastic deformation capability allows the cap to self-adjust to the second member surface, ensuring consistent quality without worker intervention.
Solution Approach 2:
The insulation structure and positioning features are pre-configured in the integrated cap design. The cap includes built-in features that automatically ensure proper alignment and contact, eliminating the need for skilled manual work in difficult-to-reach areas.
4Ease of manufacture
If the cap is engaged with the fastener member without elastic deformation capability, then installation is simple, but gaps occur with inclined surfaces and lightning-resistant performance is insufficient
Solution Approach 1:
The cap is designed with elastic deformation capability, transforming it from a rigid component to a dynamic one. The cap can elastically deform during installation to accommodate inclined surfaces and ensure continuous contact, maintaining both installation simplicity and lightning-resistant performance.
Solution Approach 2:
The physical state of the cap changes during installation through elastic deformation. The cap transitions from a relaxed state to a compressed state, changing its shape parameters to adapt to the second member surface while maintaining the air-gap insulation structure.
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
The system ensures consistent and reliable lightning-resistant performance by maintaining intimate contact between the cap and fastener member, reducing installation variability, and preventing arc discharge leakage, thus enhancing workability and reducing manufacturing costs while ensuring stable quality across different workers and temperature conditions.
Implementation Method 1
an elastically deformable part is provided to allow the cap to be elastically deformed in the direction to compress the cap between the engaged part and the tip end part abutting against the second member
Data Source
AI summary
To provide a lightning-resistant fastener capable of assuring a sufficient lightning-resistant performance. A cap 30A has an elastically deformable part 50 continuous in the circumferential direction thereof. The elastically deformable part 50 has a smaller thickness than the other parts of the cap 30A in a circumferentially continuous area thereof. Since the cap 30A has the elastically deformable part 50, even if a surface 22b of a member 22 is inclined with respect to a plane perpendicular to the axis of a fastener main body 25, the cap 30A can be installed without forming a gap.