Folding Wing Locking Pin Decoupling Under Flight Loads
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Solution Overview
Problem
Existing locking systems for foldable aircraft wings face issues with load transfer from the locking pin to the actuator, leading to potential damage and the need for oversized actuators to withstand these forces.
Innovation Solution
A locking assembly with a locking pin system where the pin is decoupled from the actuator when in the locked position, using a bore with varying diameters and engagement means that release the pin from the actuator during high loads, preventing load transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator is designed to withstand maximum anticipated forces from the locking pin, then the reliability of the locking system is improved, but the actuator becomes oversized and heavier
Solution Approach 1:
The locking system is segmented into two functional parts: the actuator that provides controlled motion, and the locking pin that bears the load. The engagement means with resilient tines create a decoupling mechanism where the actuator and locking pin are connected during actuation but separated during load-bearing, allowing each component to be optimized for its specific function without being oversized for the other's requirements.
Solution Approach 2:
The engagement means with resilient tines act as an intermediary between the actuator and locking pin. These tines engage the pin during actuation to transfer motion, then disengage to prevent load transfer. This intermediary mechanism allows the actuator to be smaller while still ensuring reliable locking, as the load path is routed through the locking pin and hinge lugs rather than through the actuator.
2Ease of operation
If the locking pin is rigidly connected to the actuator, then the actuator can reliably position the pin, but the actuator is subjected to damaging forces during flight
Solution Approach 1:
The connection between the actuator and locking pin is made dynamic rather than static. The engagement means with resilient tines provide a temporary, conditional connection that exists only when needed for actuation. During flight loads, the connection automatically changes state to disengaged, allowing the system to adapt its mechanical coupling based on operational requirements. This dynamic behavior eliminates the harmful rigid connection while preserving reliable positioning during actuation.
Solution Approach 2:
The resilient tines are designed to preemptively prevent load transfer from the locking pin to the actuator. The biasing mechanism keeps the tines in a state ready to engage during actuation but automatically causes them to disengage before significant load can be transferred. This preliminary anti-action protects the actuator from damaging forces while maintaining the ability to reliably position the pin when needed.
3Ease of manufacture
If the actuator bore is uniform in diameter, then the manufacturing is simpler, but the engagement means cannot effectively decouple from the locking pin under load
Solution Approach 1:
The actuator bore is designed with non-uniform diameter, creating different local zones with specific functions. The first section has a smaller diameter that forces the engagement means into a closed, engaged position during actuation. The second section has a larger diameter that allows the engagement means to open and disengage from the locking pin. This local differentiation of bore geometry enables the decoupling functionality while keeping the overall structure relatively simple.
Solution Approach 2:
The bore diameter parameter is changed along the axial length of the actuator to achieve the desired engagement behavior. By varying the diameter from smaller in the first section to larger in the second section, the system exploits the geometric parameter change to control the engagement means' position and state. This parameter variation enables automatic decoupling under load while maintaining a relatively simple manufacturing process compared to more complex engagement mechanisms.
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
The solution effectively decouples the locking pin from the actuator during high loads, preventing damage and allowing for a smaller, lighter actuator design, while also enabling easy removal of the pin for maintenance.
Implementation Method 1
the engagement means being biased to an open position where they are not in engagement with the locking pin
Data Source
AI summary
A locking pin system comprising: an actuator having an actuator body defining an axial bore along its length; a locking pin axially moveably mounted within the bore, and drive means for driving the locking pin axially along the bore between a locking position extending from the actuator body and an unlocking position relatively retracted into the actuator body; wherein the drive means comprises engagement means for releasably engaging the locking pin, the engagement means being biased to an open position where they are not in engagement with the locking pin, and wherein the bore comprises a first section having a first diameter and a second section having a second, wider diameter.