Wing Tip Locking Pin and Bush Assembly for Vibration Isolation
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Solution Overview
Problem
Conventional wing tip devices on large passenger aircraft lack secure fastening mechanisms, leading to play and vibrations that can cause wear and structural issues due to limitations in existing locking mechanisms.
Innovation Solution
A locking mechanism featuring a locking pin and bush with a low-friction slip path, where the frictional force required to move the bush relative to its housing is less than that required to move the locking pin, preventing wear and vibrations from being transferred to the actuator, and allowing for a smaller, lighter actuator while maintaining secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional locking mechanisms are used to fasten the wing tip device, then the wing tip device can be secured in the flight configuration, but wear in the locking mechanism results in play between the wing tip device and the fixed wing, leading to increased wear and vibrations
Solution Approach 1:
A bush is introduced as an intermediary component between the locking pin and the wing tip device housing. The bush absorbs wear and friction through its low-friction interface with the bush housing, preventing direct wear between the locking pin and the wing tip device. This mediator component protects the critical locking elements from wear while maintaining secure fastening.
Solution Approach 2:
The patent replaces a direct mechanical locking system with a low-friction bush interface. Instead of relying solely on friction and direct contact between the locking pin and housing, the system uses a bush with reduced friction characteristics to allow controlled movement while maintaining secure locking, thereby eliminating play and vibrations.
2Reliability
If a robust locking mechanism is used to prevent play, then secure fastening is achieved, but the frictional force required to move the locking pin increases, requiring a larger and heavier actuator
Solution Approach 1:
The bush acts as a mediator that reduces the frictional interface between the locking pin and the housing. By introducing this low-friction component, the actuator only needs to overcome the reduced friction at the bush interface rather than high friction between metal surfaces, enabling a smaller and lighter actuator design.
Solution Approach 2:
The patent changes the friction parameter at the locking interface by introducing a bush with low-friction characteristics. This parameter change reduces the force required by the actuator while maintaining secure locking, allowing for weight reduction in the actuator.
3Reliability
If high friction is used in the locking mechanism to prevent movement, then secure locking is achieved, but heat generation and wear increase
Solution Approach 1:
The bush serves as a thermal and wear intermediary, absorbing frictional heat through its material properties and low-friction interface. This prevents heat buildup and wear at the critical locking pin interface, maintaining locking security while reducing temperature and wear.
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 provides a secure and durable locking mechanism that reduces wear and heat generation, protects the actuator from vibrational loads, and enables a smaller, lighter actuator design while ensuring the wing tip device can safely transition between flight and ground configurations.
Implementation Method 1
the frictional force to be overcome to allow movement of the bush relative to the bush housing in the direction of the longitudinal axis is less than the frictional force to be overcome to allow movement of the locking pin relative to the bush
Data Source
AI summary
A locking pin associated with one of a fixed wing and a wing tip device, and a bush associated with the other of the fixed wing and wing tip device, the bush configured to receive the locking pin. The bush is located within a bush housing arranged to allow relative movement of the bush in the direction of a longitudinal axis of the locking pin when the locking pin is received within the bush.