Anchoring Nut Cap With Interrupted Threads for EME Sealing
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Solution Overview
Problem
Existing electrical insulation cap assemblies for metallic fasteners are time-consuming to install and require tedious smoothing of excess sealant, and lack a reliable securement mechanism, especially in critical areas like aircraft fuel tanks or sensitive electronic equipment, where rapid and secure isolation from electromagnetic effects and lightning strikes is necessary.
Innovation Solution
A cap system with a nonconductive cap member featuring a securement mechanism with interrupted or continuous threads and grooves that securely engage the nut member, allowing for easy installation and reliable sealing, using a nonconductive material and sealant to isolate the fastener assembly from its surroundings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealant is over-filled into the cap to ensure adequate sealing, then sealing reliability is improved, but excess sealant must be smoothed out which increases installation time and complexity
Solution Approach 1:
The cap is pre-filled with sealant during manufacturing before installation. This preliminary action ensures adequate sealing material is already in place, eliminating the need for on-site over-filling and subsequent smoothing operations, thus reducing installation time while maintaining sealing reliability
Solution Approach 2:
The smoothing operation is extracted and eliminated from the installation process. By pre-filling the cap with the exact amount of sealant needed and designing the cap to contain it properly, the harmful smoothing step is removed entirely from the installation workflow
2Manufacturing precision
If the cap is held in place for an extended period during curing to prevent slumping or lifting, then sealing quality is improved, but installation efficiency deteriorates
Solution Approach 1:
Securement features (threads, lugs, or adhesive elements) are pre-integrated into the cap design before installation. This preliminary preparation of securement mechanisms allows the cap to be quickly and reliably fixed during installation, eliminating the need for extended holding periods and improving installation efficiency while maintaining sealing quality
Solution Approach 2:
Adhesive elements or mechanical securement features act as intermediaries between the cap and the fastener assembly/substrate. These intermediaries provide immediate bonding or mechanical retention, preventing slumping or lifting during curing without requiring prolonged manual holding, thus improving both sealing quality and installation efficiency
3Reliability
If a securement mechanism is added to the cap to reliably attach it to the fastener assembly, then connection reliability is improved, but device complexity increases
Solution Approach 1:
The securement mechanism is merged with the cap body as an integrated feature rather than a separate component. Threads, lugs, or adhesive elements are formed as part of the cap manufacturing process, combining the sealing function and securement function into a single unified component, thus improving connection reliability without significantly increasing overall device complexity
Solution Approach 2:
The cap is designed with multi-functionality, serving both as a sealing element and as a securement device. The same cap structure that provides electrical insulation and sealing also incorporates securement features (threads, lugs, or adhesive surfaces), eliminating the need for separate securement components and maintaining simplicity while improving reliability
Data Source
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AI summary
A cap system (26A) for enclosing a metallic fastener assembly (11) extending through a structure (12) includes a first securement mechanism (34A) positioned about a periphery (36A) of a nut member of the metallic fastener assembly, wherein the first securement mechanism comprises threads (35A) which are interrupted as the threads extend about the periphery of the nut member and a cap member. The cap member (28A) includes a sidewall (29A) having an inner surface which defines a cavity dimensioned to receive the nut member and defines a second securement mechanism complementary configured to engage the first securement mechanism positioned about the periphery of the nut member and an end of the sidewall of the cap member defines an opening which provides the nut member to have access into the cavity.