Aircraft Pin Joint Assembly With Headless Pin for Tight-Space Access
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Solution Overview
Problem
The assembly or disassembly of pin joints in aircraft is impeded by limited internal space, requiring disassembly of multiple components and is time-consuming and costly due to the need for large clearance spaces and clamping mechanisms that occupy valuable space.
Innovation Solution
A pin joint assembly using a headless pin with bushings and retaining features that allow the pin to be freely rotatable, reducing the length and retention features, and enabling independent assembly direction and reduced tolerance stacks, allowing for plug-and-play functionality without disassembling non-related systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional headed pin with clamping retention features is used, then the pin joint is securely retained, but the length of pin and retention features increases occupying valuable space
Solution Approach 1:
The patent extracts the head from the pin, transforming it from a headed pin to a headless pin. This removal of the head eliminates the need for clamping retention features, significantly reducing the overall length of the pin assembly and freeing up valuable space within the aircraft wing structure while maintaining secure retention through alternative means (bushings and retaining features at opposing ends)
Solution Approach 2:
Instead of using a headed pin that clamps retention features from one end, the invention inverts the approach by using a headless pin with retention features at opposing ends. The pin passes through both end lugs and is retained by bushings and retaining features at both ends, eliminating the need for a head and clamping mechanism while securing the joint effectively
2Ease of operation
If pin is clamped between retaining features, then the pin is securely fixed, but the assembly direction is constrained and requires disassembly of multiple components
Solution Approach 1:
The patent segments the pin joint assembly into distinct functional elements: a headless pin, bushings at each end, and retaining features at opposing ends. This segmentation allows the pin to be freely inserted in either direction through the end lugs without being constrained by a head or clamping mechanism, enabling flexible assembly sequencing and independent assembly direction while maintaining secure fixation through the distributed retention features
Solution Approach 2:
The headless pin design with opposing retaining features provides universal assembly capability, allowing the pin to be inserted from either end of the assembly without requiring specific orientation or disassembly of other components. This multi-directional assembly capability simplifies maintenance and manufacturing operations while maintaining secure joint fixation
3Manufacturing precision
If traditional pin joint design with clamping is used, then the connection is secure, but the tolerance stack is longer and requires higher tolerance precision
Solution Approach 1:
The invention inverts the traditional clamping approach by eliminating the head and single-end retention, instead using a headless pin with retaining features at opposing ends. This inversion creates a shorter, more compact tolerance stack with fewer contributors (bushings and retaining features at two ends versus a head and clamping mechanism), reducing the cumulative tolerance requirements and simplifying manufacturing precision needs while maintaining secure connection
Data Source
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AI summary
A pin joint assembly comprising: 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 comprising 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.