Headless Pin Joint Assembly for Tight-Clearance Aircraft Installation
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Solution Overview
Problem
The assembly or disassembly of pin joints in aircraft is hindered by the need for large clearance spaces, leading to time-consuming and costly processes due to interference with other components, and existing designs have high tolerance stacks and complex retention mechanisms.
Innovation Solution
A pin joint assembly using a headless pin isolated from retaining features, with bushings and pin retainers that allow independent assembly direction and reduced tolerance requirements, enabling plug-and-play functionality and space restoration within aircraft structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional headed pin design with retaining features is used, then the pin joint can be securely retained, but the length of pin and retention features increases, reducing available space in aircraft
Solution Approach 1:
The invention extracts the head from the pin, creating a headless pin design. This removes the need for traditional retaining features that clamp the headed pin, thereby reducing the overall length of the assembly and restoring space within the aircraft structure while maintaining secure retention through alternative means (bushings and pin retainers)
Solution Approach 2:
The invention segments the retention function from the pin itself by introducing separate components (bushings and pin retainers) that perform the retention function. This allows the pin to be simpler and shorter while the retention features are distributed as separate, optimized components
2Manufacturing precision
If traditional pin joint assembly is used, then the pin can be retained between retaining features, but the tolerance stack is long with many contributors, increasing manufacturing difficulty
Solution Approach 1:
By segmenting the retention function into separate bushings and pin retainers, the invention reduces the number of components that contribute to the tolerance stack. The headless pin design eliminates the need for multiple retaining features along the pin length, thereby reducing the cumulative tolerance requirements and simplifying manufacturing precision requirements
3Ease of operation
If traditional pin joint assembly is used, then the retaining features clamp the headed pin, but the assembly direction is constrained and requires disassembly of multiple components
Solution Approach 1:
By removing the head from the pin, the invention eliminates the constraint on assembly direction. The headless pin can be inserted from either end of the pin hole, allowing assembly in the most convenient direction without being constrained by the need to accommodate a head. This enables plug-and-play functionality where jointed components can be assembled independently of the pin orientation
Solution Approach 2:
The invention inverts the traditional approach by making the pin headless rather than having a head. This inversion allows the pin to be inserted from either direction, fundamentally changing the assembly process to be more flexible and independent of retaining feature orientation
Data Source
AI summary
A pin joint assembly including: a first end lug and a second end lug; a pin hole extending through the first and second end lugs; a first retaining feature and a second retaining feature arrangeable at opposing ends of the pin hole; a headless pin including a pin body for inserting through the pin hole to rotatably couple the first and second end lugs, such that the pin body is retained between the first and second retaining features; a first bushing for positioning between the headless pin and the first end lug, and a second bushing for positioning between the headless pin and the second end lug; wherein the headless pin is isolated from the first and second retaining features.