Airplane Fuselage Girder Junction With Plastic Insert
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Solution Overview
Problem
Existing airplane wing mounting solutions require stringent precise manufacturing tolerances, making them susceptible to production irregularities and limiting flexibility in assembly.
Innovation Solution
A junction comprising a former with a rectangular cross-sectional opening and a frusto-pyramidal girder with a rectangular base, featuring a plastic insert and blind rivet coupling, allows for precise and reliable seating of the girder within the former, accommodating production irregularities and enabling a threaded connection through aligned mounting openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional junction solutions with girders seated in formers are used, then lifting elements can be mounted and forces distributed, but stringent precise manufacturing tolerances are required making the system susceptible to production irregularities
Solution Approach 1:
The patent changes the geometric parameters of the girder end and former opening to create a frusto-pyramidal shape with a rectangular base. This geometric transformation allows the girder to be self-positioning within the former, converting a precision-fit requirement into a form-guided assembly that tolerates manufacturing variations while ensuring reliable force distribution.
Solution Approach 2:
The insert made of plastics is introduced as an intermediary element between the girder and the former. This insert facilitates the coupling by providing a compliant interface that accommodates manufacturing tolerances, enabling reliable mounting without requiring stringent precision in the metal components while still ensuring proper force distribution.
2Manufacturing precision
If precise manufacturing tolerances are required for all elements, then correct mounting is achieved, but production irregularities cannot be corrected and assembly flexibility is limited
Solution Approach 1:
The frusto-pyramidal geometry of the girder end creates a tapered fit within the rectangular former opening. This parameter change allows the assembly to accommodate a range of manufacturing tolerances while maintaining correct positioning, thereby increasing assembly flexibility without sacrificing mounting precision. Production irregularities within a broader tolerance range can be corrected through this geometric design.
3Measurement precision
If a frusto-pyramidal girder with rectangular base is used in a former with rectangular opening, then the girder can be precisely seated and positioned, but the structure becomes more complex
Solution Approach 1:
The patent employs asymmetric geometry by using a frusto-pyramidal shape for the girder end rather than a simple cylindrical or rectangular form. This asymmetric design provides self-positioning characteristics that ensure precise seating and orientation within the rectangular former opening, achieving high positioning precision while the asymmetry itself becomes the simplifying feature rather than a source of complexity.
Solution Approach 2:
The frusto-pyramidal girder end is designed to self-position within the rectangular former opening during assembly. The geometric constraints of the tapered shape automatically guide the girder into the correct position and orientation, eliminating the need for additional positioning mechanisms or complex alignment procedures, thereby achieving precise positioning without proportionally increasing structural complexity.
Data Source
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AI summary
The invention provides a junction of metal/composite structures of an airplane where in a former (2) of the airplane fuselage (4) a girder (1) is seated and coupled, to which bearing elements of the airplane are mounted, such as wings or elements of flight controls of the airplane, in particular a small plane. A junction is characterized in that in the former (2) of the airplane fuselage (4) an insert (3) is positioned that has an outer shape that represents the inner shape of the former (2) of the fuselage (4) and its inner shape represents the outer shape of an end of the girder (1), where the height of the insert (3) as measured along an opening in the former (2) corresponds to at most a half od he depth of the opening in the former (2).