Pivoting Landing Gear Immobilization With Shear-Force Unlocking
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Solution Overview
Problem
Existing pivoting landing gear immobilization systems in aircraft are prone to sudden destabilization due to shearing forces, particularly when subjected to significant transverse thrust, making it difficult to unlock the system safely and reliably.
Innovation Solution
A landing gear immobilization system with a movable pin and an elastic locking/unlocking mechanism that allows the pin to move in a passage only when shearing forces are below a threshold, preventing unlocking during high-stress conditions and ensuring safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the immobilization system is designed to lock the pivoting landing gear firmly to prevent movement, then the reliability of the landing gear positioning is improved, but the ease of operation deteriorates because the system becomes difficult to unlock when subjected to shearing forces
Solution Approach 1:
The pin is designed to be movable relative to the base rather than fixed, allowing it to move in response to shearing forces. This dynamic behavior enables the system to automatically adjust its locking state based on operational conditions, resolving the contradiction between firm locking and ease of unlocking.
Solution Approach 2:
The system changes the positional parameter of the pin relative to the base and passage based on the magnitude of shearing forces. When forces exceed a threshold, the pin moves to a position where it no longer constrains the landing gear, enabling automatic unlocking without manual intervention.
2Ease of manufacture
If the pin is designed to move in translation rather than rotation, then the ease of manufacture is improved, but the reliability deteriorates because the pin cannot effectively engage with the passage in all orientations
Solution Approach 1:
The pin movement is designed to occur in a specific dimension (translation along the longitudinal axis) rather than rotation. This dimensional approach simplifies manufacturing while the passage geometry is designed to accommodate this specific movement pattern, ensuring reliable engagement when the pin translates into the correct position.
3Ease of operation
If the elastic locking system is designed to push the pin into the passage automatically, then the ease of operation is improved, but the reliability deteriorates because the pin may be forced into the passage during high-stress conditions causing destabilization
Solution Approach 1:
The elastic locking system provides feedback based on the operational state of the landing gear. When the gear is in a stable state, the elastic force pushes the pin into the passage for automatic locking. When high shearing forces indicate unstable conditions, the pin moves out of the passage, preventing forced locking and potential destabilization.
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 system effectively prevents sudden destabilization by allowing unlocking only when safe conditions are met, enhancing safety and reliability of the landing gear operation.
Implementation Method 1
the immobilization system having an elastic locking system pushing the pin into the passage in the locked mode
Data Source
AI summary
A landing gear provided with a stand and a pivoting assembly carrying a contact member and able to rotate about a pivot axis in relation to the stand. An immobilization system comprises a movable pin and a passage provided in a base secured to the pivoting assembly. An elastic locking system tends to push the pin into the passage in a locked mode. An elastic unlocking system is configured to move the pin out of the passage when activation of an unlocked mode is commanded by a control, the elastic unlocking system being calibrated to allow the pin to be extracted from the passage only when there is a shearing force less than a threshold between the base and the pin.