Injectable Fastener Cap With Flow Channels for Gap-Free Sealing
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Solution Overview
Problem
Existing fastener sealing technologies are inadequate in preventing air gaps and contamination, especially in structures prone to lightning strikes, as they require pre-curing sealing materials and do not effectively secure the cap during injection, leading to potential sparking and out-gassing events.
Innovation Solution
A cap with a cavity and ridges that injects sealing material post-installation, using channels to ensure a stable bond and seal, with ridges gripping the fastener to prevent dislodgment and forming a continuous bead around the annular rim for enhanced sealing and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-cured sealing materials are used in existing fastener sealing technologies, then the sealing process can be simplified, but air gaps and contamination cannot be effectively prevented
Solution Approach 1:
The cap is pre-positioned onto the fastener before sealing material injection, and the sealing material is injected through channels to fill the cavity and form a continuous bead. This preliminary positioning ensures proper alignment and prevents air gaps while maintaining manufacturing simplicity.
Solution Approach 2:
Injection channels serve as intermediaries to deliver sealing material from the injection source to the cavity interior. These channels ensure complete filling and eliminate air pockets, while the cap structure acts as an intermediary container that maintains seal integrity during the process.
2Reliability
If quick-cure sealing materials are used, then a stable bond is provided quickly, but the material must be applied during its short working life
Solution Approach 1:
The cap is positioned onto the fastener and the injection system is prepared before the sealing material is injected. This preliminary preparation ensures that the material is applied immediately upon injection, utilizing its full working life to achieve rapid curing and stable bonding.
Solution Approach 2:
The sealing material is injected under pressure through channels into the cavity, ensuring rapid and complete filling. This hydraulic injection method delivers the material quickly and efficiently, maximizing the utilization of the short working life of quick-cure materials.
3Reliability
If the cap is secured during injection, then dislodgment is prevented, but additional features like snap-fit projections are required
Solution Approach 1:
The cap is pre-positioned onto the fastener before injection begins. This preliminary positioning, combined with the injection process itself, secures the cap in place without requiring complex additional features, thereby maintaining structural simplicity while ensuring stability.
4Reliability
If a continuous bead of sealing material is formed around the annular rim, then a large contact area is achieved, but the sealing material must flow out of the cavity
Solution Approach 1:
The annular rim acts as an intermediary feature that guides the sealing material as it exits the cavity. The material flows along the rim to form a continuous bead, creating a large contact area for bonding while the rim structure controls and directs the flow process efficiently.
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 solution provides a quick, stable bond and seal that withstands accidental knocks, prevents air gaps and contamination, and effectively secures the cap, thereby preventing sparking and out-gassing events during lightning strikes.
Implementation Method 1
injecting sealing material into the cavity via the sealing material inlet so that the sealing material flows along the channels, fills the cavity, contacts the end of the fastener, and contacts the structure; and curing the sealing material to form the seal
Data Source
AI summary
The description provides a method of forming a seal around an end of a fastener protruding from a structure. The cap includes a cap body with a cavity; a sealing material inlet comprising an opening in the cap body; three or more ridges protruding from the cap body into the cavity; and three or more channels between the ridges. The method includes: installing the cap body over the end of the fastener so that it is enclosed within the cavity and contacted by the ridges; injecting sealing material into the cavity via the sealing material inlet so that the sealing material flows along the channels, fills the cavity, contacts the end of the fastener, and contacts the structure; and curing the sealing material to form the seal.