Threaded Fastener Seal Cap Structure for Controlled Sealant Flow
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Solution Overview
Problem
Conventional seal cap devices for threaded fasteners in the aerospace industry face issues with excess sealant material usage, leading to increased aircraft weight and unsightly finishes, and inconsistent sealing due to unreliable coaxial centering.
Innovation Solution
A seal cap device with an open-ended cylindrical body and a beveled transition annulus, featuring radially extending slots and circumferentially spaced openings to control sealant flow, allowing for minimal excess sealant use and reliable sealing, suitable for both manual and automated applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seal caps are pre-filled with ambiently curable viscous sealant material and manually pressed onto fasteners, then sealing function is achieved, but excess sealant material is used increasing aircraft weight
Solution Approach 1:
The patent changes the physical state of sealant material from ambiently curable viscous to molten state, allowing precise control of flow and minimal excess material. The molten sealant is injected in controlled amounts and solidifies upon contact with the cooler seal cap interior, eliminating the need for excessive material application.
Solution Approach 2:
The patent replaces the manual pressing mechanical system with an automated injection system that delivers molten sealant through a nozzle. This substitution enables precise metering of sealant material, reducing excess application and consequently reducing aircraft weight while maintaining reliable sealing.
2Reliability
If conventional seal caps are manually pressed onto fasteners, then sealing is achieved, but coaxial centering cannot be reliably ensured resulting in less than desirable fluid seal
Solution Approach 1:
The patent replaces manual pressing with an automated injection molding process that uses a sprue and nozzle system. This mechanical system automatically centers the seal cap on the fastener during injection, ensuring reliable coaxial alignment and consistent fluid sealing without depending on operator skill.
Solution Approach 2:
The patent incorporates a sprue (gate structure) in the seal cap design that is formed during injection molding. This sprue acts as a preliminary centering feature that guides the nozzle and ensures coaxial alignment before sealant injection begins, preventing misalignment issues.
3Reliability
If excess sealant material is used to ensure adequate sealing, then sealing reliability is improved, but aircraft weight increases and finish becomes unsightly
Solution Approach 1:
The patent changes sealant material state to molten and controls its flow through injection pressure and temperature parameters. This allows precise delivery of only the necessary amount of sealant material, preventing excess that would create unsightly finish while ensuring adequate sealing through controlled distribution.
Solution Approach 2:
The automated injection system replaces manual application, providing precise metering and control of sealant material flow. This substitution eliminates the tendency to over-apply material, ensuring both aesthetic finish and sealing reliability through consistent, controlled delivery.
4Ease of operation
If manual pressing method is used for seal cap application, then flexibility in operation is maintained, but productivity and consistency are reduced
Solution Approach 1:
The patent replaces manual pressing with an automated injection molding system that can rapidly inject and solidify sealant material. This substitution dramatically increases productivity by eliminating manual operation time per fastener while maintaining consistency through automated process control.
Solution Approach 2:
The patent utilizes the phase transition of sealant material from molten to solid state during injection molding. This phase change occurs rapidly upon contact with the cooler mold cavity, enabling quick cycle times and high productivity while ensuring consistent sealing quality for each fastener.
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 enables reliable fluid sealing with minimal excess sealant, ensuring a consistent and aesthetically pleasing finish while accommodating both manual and automated sealing processes, effectively addressing the weight and centering issues of conventional devices.
Implementation Method 1
A bottom edge of the cylindrical body member (or base) may define a series of circumferentially spaced-apart openings to allow an amount of flowable sealant material which is present in the interior space of the body member to seep or exude therethrough and form a bead of sealant material at the bottom edge
Data Source
AI summary
Seal cap devices are provided as an integral (one-piece) structure comprising an open-ended cylindrical body member sized so as to surround a threaded shaft of a fastener, the body member including an upper wall having (i) an arcuate interior edge which defines an aperture to allow threaded engagement with distalmost threads of the threaded shaft of the fastener, and (ii) at least one slot radially extending from the aperture. The upper wall may include opposed slots radially extending from the aperture, e.g., a pair of opposed slots radially extending from the aperture that are separated from one another by an angle of about 90°. A sealant material within the cap may therefore envelope the threaded shaft of the fastener and any collar nut associated therewith to provide a reliable seal.