Aircraft Landing Gear Split Tube Spring Locking Mechanism
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Solution Overview
Problem
Existing aircraft landing gear assemblies are susceptible to bird strikes, tyre debris impacts, and early fatigue rupture due to vibratory loading, aerodynamic effects, and airframe vibrations, leading to reliability and maintenance issues.
Innovation Solution
The implementation of a split tube spring with a longitudinal slot, biased to assume a tubular condition for locking the main shock absorbing strut in place, which can fold to allow retraction, replacing conventional lock links and stays, thereby reducing complexity, weight, and maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lock links and stays are used to lock the landing gear in deployed condition, then the landing gear can be reliably locked, but the assembly complexity and weight increase
Solution Approach 1:
The patent combines the lock link, stay, and down lock spring functions into a single integrated split tube spring assembly. The split tube spring serves multiple functions: it acts as the locking element, the stay linkage, and the down lock mechanism simultaneously, eliminating the need for separate components and reducing overall system complexity while maintaining reliable locking.
Solution Approach 2:
The split tube spring is designed as a multi-functional component that performs locking, bracing, and energy storage functions. It can react axial loading when in the locked tubular condition while also providing the necessary linkage and locking action, making a single component perform the work of multiple traditional parts.
2Ease of operation
If multiple pin joints and linkage components are used in the stay assembly, then the landing gear can achieve locked and unlocked conditions, but maintenance requirements and wear increase
Solution Approach 1:
By merging multiple separate linkage components with pin joints into a single split tube spring assembly, the patent eliminates numerous contact surfaces and potential wear points. The integrated design reduces the number of moving parts that require lubrication and inspection, thereby lowering maintenance requirements while preserving the ability to achieve both locked and unlocked conditions.
3Reliability
If conventional stay and lock link assemblies are used, then the landing gear can be locked in deployed condition, but the weight of the assembly increases
Solution Approach 1:
The patent reduces weight by combining multiple separate components (lock link, stay, down lock spring) into a single integrated split tube spring assembly. This consolidation eliminates the weight of redundant components and fasteners while maintaining the necessary locking functionality through the multi-functional design of the split tube spring.
4Object-affected harmful factors
If the landing gear assembly is susceptible to bird strikes and debris impacts, then external objects can damage conventional linkage components, but the split tube spring design reduces vulnerability
Solution Approach 1:
The split tube spring design inherently provides more impact resistance compared to rigid linkage components with pin joints. The spring's flexible tubular structure can better absorb and distribute impact forces from bird strikes or debris, reducing the likelihood of catastrophic failure while maintaining reliability through its elastic properties.
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 split tube spring enhances the reliability and reduces maintenance of the landing gear assembly by eliminating the need for additional lock links and down lock springs, while providing a simpler and lighter alternative that can withstand axial loading and facilitate smooth retraction.
Implementation Method 1
the spring being biased to assume a tubular condition in which it can react axial loading thereof
Implementation Method 2
an actuator operable to radially enlarge a region of the tube for the tube to fold at the enlarged region
Data Source
AI summary
An aircraft landing gear assembly includes a bi-stable, split line tube biased to assume a tubular condition to serve in place of a lock link or side stay and an actuator configured to radially enlarge the tube at a region for folding.