Thermoplastic EME Protection Cap Assembly Without Sealant
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Solution Overview
Problem
The installation of electromagnetic effect (EME) protection caps on structures like aircraft is hindered by the use of sealants, which can lead to defective installations due to decompression or gravitational forces, resulting in increased costs and labor, and the need for hazardous adhesion promoters.
Innovation Solution
A protection cap assembly that secures to a structure without sealants, using a thermoplastic projection member that is melted and cooled to adhere to both the cap and the structure, providing a secure and interference-fit-based installation method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealant is used to secure the protection cap to the structure, then the protection cap can be attached to the structure, but the installation becomes time-consuming and prone to defective installations due to sealant decompression or gravitational forces
Solution Approach 1:
The invention removes the sealant from the installation process entirely. The protection cap is designed with an integrated sealing mechanism that creates a seal between the cap and structure without requiring separate sealant application, curing, or cleanup operations.
Solution Approach 2:
The protection cap is divided into functional segments: a sealing portion that contacts the structure to create a seal, and a fastening portion that secures the cap. This segmentation allows each component to perform its specific function efficiently without relying on sealant.
2Ease of manufacture
If sealant is used to secure the protection cap, then the cap can be attached, but additional labor and cost are required for sealant application and cleanup
Solution Approach 1:
The sealing function and fastening function are merged into a single integrated protection cap assembly. The sealing portion and fastening portion work together as one unit, eliminating the need for separate sealant application and cleanup steps.
3Reliability
If adhesion promoter is used with polysulfide sealant on thermoplastic structures, then necessary adhesion is achieved, but hazardous chemicals are introduced
Solution Approach 1:
The invention removes hazardous chemicals (adhesion promoters and polysulfide sealants) from the installation process. The sealing portion achieves reliable adhesion through mechanical interference and material compatibility rather than chemical bonding agents.
4Reliability
If protection caps are installed during aircraft fabrication or maintenance, then electromagnetic protection is provided, but time and productivity are reduced due to sealant curing requirements
Solution Approach 1:
The sealing portion is pre-configured on the protection cap during manufacturing, ready for immediate installation. The interference fit mechanism is pre-engineered to provide instant mechanical attachment and sealing upon installation, eliminating on-site sealant application and curing wait time.
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 and speeds up the installation of protection caps, reducing labor and material costs while eliminating the need for hazardous chemicals, ensuring reliable and efficient electromagnetic shielding without sealants.
Implementation Method 1
applying heat to the thermoplastic material of the projection member melting the thermoplastic material
Implementation Method 2
cooling the thermoplastic material of the projection member such that the thermoplastic material of the projection member solidifies and adheres to the cap member and the structure
Implementation Method 3
The projection member is positioned between the inside edge and the outside edge of the end surface
Data Source
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AI summary
A protection cap assembly (10) for enclosing an end portion (12) of a fastener (1k4) which extends through a structure (16) of an aircraft includes a cap member (18) having a sidewall (20) defining an opening (20) and an interior space (24) wherein the opening is aligned with the interior space for receiving the end portion of the fastener through the opening and into the interior space and an end surface (26) for abutting the structure. The protection cap assembly further includes a projection (28) secured to and which extends from the end surface of the sidewall of the cap member.