Offset-Appendage Tenon Fastening for Drill-Free Aircraft Assembly
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Solution Overview
Problem
Aircraft assembly requires precise machining operations to align fastening holes, which is time-consuming and undesirable, and existing systems struggle to ensure satisfactory assembly without drilling or adjustment.
Innovation Solution
A mechanical fastening system featuring tenons with angled appendages and a resilient interposed plate, allowing for alignment and locking without drilling, using a thread-based locking mechanism and washers to accommodate poor tolerances and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional riveting systems with pre-drilled holes are used, then components can be securely fastened, but precise machining operations are required to align holes which is time-consuming
Solution Approach 1:
The fastening system is segmented into modular components: tenons with appendages that extend from the plate, end fittings with slots, and locking devices. This segmentation allows each component to be independently manufactured with standard tolerances and assembled without precise pre-alignment, eliminating the need for time-consuming machining operations while maintaining secure fastening.
Solution Approach 2:
The tenons are pre-formed with appendages during manufacturing, and the end fittings are pre-formed with slots. These preliminary actions allow the components to be designed with built-in alignment features that guide assembly without requiring on-site drilling or adjustment, significantly reducing assembly time.
2Ease of manufacture
If tenons with angularly offset appendages are used, then alignment without drilling is achieved, but the device complexity increases
Solution Approach 1:
The appendages on the tenons are positioned at angular offsets (e.g., 90 degrees) rather than symmetrically. This asymmetric arrangement creates unique alignment characteristics where the angled appendages naturally guide the end fittings into proper orientation during assembly, eliminating the need for drilling while the geometric simplicity of the asymmetric form keeps manufacturing straightforward.
Solution Approach 2:
The appendages extend in multiple directions (angularly offset in different longitudinal directions) from the tenon, adding dimensional complexity to the fastening geometry. This multi-directional arrangement allows the system to achieve alignment in multiple degrees of freedom without requiring complex machining, as the angular positions provide natural guidance during assembly.
3Object-affected harmful factors
If a resilient interposed plate is used, then vibration filtering is achieved, but the structural rigidity may be reduced
Solution Approach 1:
The interposed plate incorporates a resilient part that changes the mechanical parameters of the assembly by introducing controlled elasticity. This resilient element filters vibrations through its damping properties while the overall structural rigidity is maintained by the rigid tenons, end fittings, and locking devices that provide the primary load-bearing path.
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
Enables rapid and stress-free assembly of aircraft components without machining, ensuring precise alignment and force transmission in multiple directions, while allowing for easy disassembly and vibration filtering.
Implementation Method 1
the interposed plate may include a resilient part... vibration filtering
Implementation Method 2
the coupling means are in the form of a thread on the appendages... A nut is provided for each appendage in order to lock the washer
Implementation Method 3
each block has a lateral face against which a washer bears... to lock the washer to a lateral face
Data Source
AI summary
A system for fastening two components is disclosed having a mechanical connection device including two tenons that each extend from an opposite face of an interposed plate, each of the tenons having two appendages forming coupling arms, each appendage being positioned on either side of the tenon. The appendages of one tenon being positioned in a different longitudinal direction than the appendages of the other tenon, each appendage having a coupling component to connect to a device for locking the tenons and two end fittings that each have a slot in which each of the tenons of the connection device is able to be fitted, each appendage protruding out of the slot on either side thereof.