Adjustable Offset Mounting Assembly for Aircraft Fuel Tubes
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Solution Overview
Problem
In aircraft fuel systems, particularly in composite wing structures, there is a need for pass-through mounting assemblies that can reduce electromagnetic effects, accommodate tubing alignment, and permit tubing movement while ensuring secure retention and minimizing stress on both the tubing and the structure, due to the challenges of electromagnetic interference, structural flexibility, and harsh environments.
Innovation Solution
The solution involves a pass-through mounting assembly comprising an outer sleeve, an inner sleeve, a bushing component, and a cap, which are configured to be assembled onto a partition aperture to retain a tube, providing adjustable angular and radial positioning of the tube aperture to match the tube's position, thereby reducing electromagnetic interference and stress on the tube and partition, and including electrically insulating components to prevent arcing and dielectric breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional metal mounting assemblies are used in composite wing structures, then electromagnetic shielding is improved, but induced currents and arcing risks increase due to lesser shielding in composite materials
Solution Approach 1:
The mounting assembly is divided into multiple separate components (mounting block, tube clamp, retaining cap) that can be independently positioned and adjusted. This segmentation allows each component to be optimized for electromagnetic isolation while maintaining structural function, reducing induced currents through distributed positioning rather than a single continuous metal structure
Solution Approach 2:
The mounting assembly introduces intermediate non-conductive elements between the conductive tube and the composite wing structure. These intermediaries act as mediators that prevent direct electromagnetic coupling and reduce induced currents while still providing mechanical support and retention
2Strength
If rigid mounting assemblies are used to secure tubing, then retention strength is improved, but stress and damage risk increase due to composite wing flexibility and tubing misalignment
Solution Approach 1:
The tube clamp incorporates a resilient or adjustable mechanism that allows dynamic adaptation to tubing position variations. The clamp can flex or be positioned at different angles to accommodate composite wing flexibility and tubing misalignment, maintaining secure retention without applying excessive stress to the tubing
Solution Approach 2:
The mounting assembly allows adjustment of geometric parameters such as the angular position of the tube clamp relative to the mounting block. This parameter adjustment enables optimization of both retention strength and stress distribution, accommodating variations in tubing alignment while maintaining secure retention
3Manufacturing precision
If adjustable angular positioning is implemented for tube aperture, then alignment with tubing is improved, but device complexity increases
Solution Approach 1:
The adjustable angular positioning is achieved through segmentation of the mounting assembly into independently rotatable or adjustable components. The tube clamp can be positioned at different angular orientations relative to the mounting block, allowing alignment precision without requiring a completely redesigned complex mechanism
Solution Approach 2:
The mounting assembly uses nested components where the tube clamp fits within or around the mounting block structure. This nesting allows for compact integration of adjustment mechanisms while maintaining alignment precision, reducing overall device complexity compared to separate adjustable components
4Reliability
If electrically insulating components are used to prevent arcing, then electromagnetic safety is improved, but electrical conductivity and grounding capability deteriorate
Solution Approach 1:
The mounting assembly segments the electrical path into insulating and conductive portions. Non-conductive mounting block and tube clamp components prevent arcing and electromagnetic interference, while separate grounding connections can be established at appropriate locations to maintain grounding capability without compromising electromagnetic safety
Solution Approach 2:
Electrically insulating materials serve as intermediaries between conductive elements (tube and grounding points). These intermediaries prevent direct electrical contact that could cause arcing, while still allowing for controlled grounding paths to be established through designated connection points, balancing electromagnetic safety with grounding requirements
Data Source
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AI summary
Pass-through mounting assemblies (20) include an outer sleeve (30), an inner sleeve (40), a bushing component (60), and a cap (80) that are configured to be assembled onto a partition aperture (12) in a partition to retain a tube (16) as the tube passes through the partition (10). The outer sleeve (30) is sized to fit into the partition aperture (12). The inner sleeve (40) is sized to nest into the outer sleeve (30) and includes a non-concentric inner rim (48). The bushing component (60) defines a tube aperture (28) configured to retain the tube and includes an outer rim (68) sized to nest into the inner rim (48) of the inner sleeve (40). The tube aperture (28) is non-concentric with the outer rim (68) of the bushing component (60). The cap includes an inner rim (48) sized to nest over the outer rim (68) of the inner sleeve (40). The tube aperture (28) position may be adjusted by changing the relative angular position of the bushing component (60), the inner sleeve (40), and the cap (80).