Aircraft Pylon Assembly Using Angle Brackets to Eliminate Shims
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Solution Overview
Problem
The assembly of an aircraft pylon's primary structure is time-consuming and costly due to manufacturing tolerances requiring significant measurement and adjustment of mounting clearances, necessitating the use of peelable shims to fill these clearances.
Innovation Solution
The assembly method involves fixing angle brackets to form L or U shapes on longitudinal and lateral members, allowing these components to be directly aligned with transverse frames without gaps, eliminating the need for shims and reducing the necessity for precise dimensional tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manufacturing tolerances are made very small to reduce mounting clearances, then the structural precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent introduces angle brackets as intermediary components between the longitudinal members and transverse frames. These angle brackets serve as mediators that absorb and compensate for manufacturing tolerances, eliminating the need for extremely tight tolerances on the main structural components while maintaining precise final assembly.
Solution Approach 2:
The patent divides the connection structure into separate modular components: longitudinal members, transverse frames, and angle brackets. This segmentation allows each component to be manufactured with relaxed tolerances independently, while the assembly of these segments achieves the required overall precision through the design of the connection interfaces.
2Manufacturing precision
If manufacturing tolerances are made very small to reduce mounting clearances, then the structural precision is improved, but the assembly time increases due to measurement and shim adjustment
Solution Approach 1:
The angle brackets are pre-assembled to form U-shapes or L-shapes with integrated mounting features before being installed on the main structure. This preliminary preparation of connection elements with built-in alignment features eliminates the need for time-consuming measurement and shim adjustment during final assembly.
Solution Approach 2:
The angle brackets serve as intermediary components that incorporate pre-drilled holes and mounting features, allowing for direct bolting of transverse frames to longitudinal members without requiring precise measurement and shim placement to eliminate gaps.
3Stability of the object's composition
If peelable shims are used to fill mounting clearances, then the structural gap elimination is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the need for peelable shims by redesigning the connection geometry. The angle brackets are designed with integrated mounting surfaces and pre-positioned holes that directly receive fasteners, removing the shim layer from the assembly process entirely.
Solution Approach 2:
The angle brackets are designed to self-align and self-position the transverse frames relative to longitudinal members through their geometric configuration and integrated mounting features, eliminating the need for external shim components to fill gaps.
Data Source
AI summary
A method for assembling a primary structure of an aircraft pylon, includes a step of fixing an angle bracket to each of the first and second lateral panels such as to obtain an L form for each of the first and second lateral panels prior to a placement of said L forms each placed against two sides of each transverse frame. This assembly technique makes it possible to reduce the mounting clearances such that it is unnecessary to fit shims, resulting in a reduction of mounting time and manufacturing costs.