Anti-buckling Coupling Device for Aircraft Piping
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Solution Overview
Problem
Existing anti-buckling coupling devices for piping in aircraft fuel systems are inefficient in managing exceptional stress variations, leading to increased mass and potential disconnection risks due to excessive radial gaps and elongated skirt lengths, which compromise hermeticity and structural integrity.
Innovation Solution
A coupling device with withdrawable translational movement stoppers that allow additional travel under exceptional stress conditions, reducing the need for extensive radial gaps and elongated skirts, while maintaining hermeticity and structural integrity by limiting travel to a safety distance only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insertion length of skirts into couplings is increased to accommodate exceptional stress variations, then the piping can preserve hermeticity under crash conditions, but the mass of the piping increases significantly
Solution Approach 1:
The patent applies the dynamics principle by making the stopper means withdrawable under exceptional stress conditions. The stoppers are designed to be present during normal operation to limit travel and maintain hermeticity, but automatically withdraw when exceptional forces are detected, allowing the system to adapt its behavior based on operating conditions. This resolves the contradiction by providing the benefits of long insertion length only when needed, rather than permanently.
Solution Approach 2:
The patent changes the parameter of stopper presence/absence based on stress conditions. During normal operation, stoppers are present limiting travel to d1. Under exceptional stress, the stoppers withdraw allowing additional travel up to d. This parameter change allows the system to optimize between hermeticity and mass reduction by adjusting the effective insertion length dynamically rather than using a fixed design.
2Ease of manufacture
If the radial gap between skirts and coupling bores is increased to allow misalignment accommodation, then assembly becomes easier and misalignment is tolerated, but the structural integrity and hermeticity are compromised
Solution Approach 1:
The stopper means dynamically adjust the effective radial constraint based on operational needs. During normal operation, stoppers maintain optimal contact to ensure hermeticity. Under exceptional stress or misalignment conditions, the withdrawable nature of stoppers allows the system to accommodate larger radial deviations without compromising the sealing surface, as the stoppers can withdraw to allow greater movement while seals maintain contact.
3Reliability
If translational movement stoppers are added to prevent disconnection under exceptional stress, then the ducts remain connected during crash situations, but the device complexity increases
Solution Approach 1:
The patent extracts the stopper function from a permanent, always-present component and makes it withdrawable. The stoppers are taken out of the coupling during exceptional stress conditions when they are no longer needed, allowing the system to simplify its structure dynamically. This reduces device complexity by removing unnecessary components during normal operation while maintaining protection during crash conditions.
Solution Approach 2:
The stopper means are designed as sacrificial or temporary protective elements that serve their purpose during exceptional stress and can be withdrawn or replaced. They are not permanent fixtures but temporary measures activated only when needed, similar to disposable safety components. This approach reduces overall device complexity by using simple, replaceable elements rather than complex permanent structures.
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 effectively reduces the added mass and maintains hermeticity by allowing the coupling to accommodate exceptional stress variations without compromising the structural integrity of the piping, ensuring the ducts remain connected and safe under both normal and exceptional conditions.
Implementation Method 1
Each coupling comprises sealing means (155) producing a substantially elastic annular linkage between the skirt (121, 122) of the duct and the interior bore of the couplings (131, 132)
Implementation Method 2
The couplings (131, 132) comprise translational movement stoppers (165) to avoid the accumulation of elastic deformations over time leading to one extremity of the duct becoming disconnected from the coupling
Data Source
AI summary
A coupling device for piping including a duct; a coupling with a hermetic longitudinal sliding connection with an extremity of the duct along a total distance parallel to a longitudinal axis of the duct; a device to stop the translational movement of a first extremity of the duct in the coupling for a travel distance less than the total distance. The device being withdrawable for a defined compression condition of the duct.