Split-Tube Landing Gear Locking With Fluid-Actuated Folding
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Solution Overview
Problem
Conventional aircraft landing gear assemblies are heavy, complex, and require multiple pieces, leading to increased weight, maintenance needs, and potential reliability issues due to the use of numerous pin joints and additional lock links.
Innovation Solution
The use of a tubular spring with a longitudinal slot, acting as a bi-stable split line tube, and a flexible vessel actuator that folds under increased fluid pressure to lock and unlock the landing gear, reducing the number of individual pieces and eliminating the need for additional lock links, thereby simplifying the assembly and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lock links and multiple pin joints are used to lock the stay in aligned condition, then the landing gear assembly achieves reliable locking, but the weight and complexity of the assembly increases
Solution Approach 1:
The patent combines the lock link, pin joints, and stay alignment mechanism into a single integrated tubular spring with a longitudinal slot. This spring performs both the locking function and the alignment function simultaneously, eliminating the need for separate lock links and multiple pin joints, thereby reducing weight while maintaining reliability
Solution Approach 2:
The tubular spring with longitudinal slot serves multiple functions: it acts as a lock mechanism, provides structural support, enables folding motion, and maintains alignment. This multi-functional component replaces several single-function components (lock link, pin joints, stay), reducing overall assembly weight and complexity
2Reliability
If multiple pin joints and additional lock links are provided to maintain the stay in aligned condition, then the locking function is achieved, but the number of components and maintenance needs increases
Solution Approach 1:
The patent merges the lock link, pin joints, and stay into a single tubular spring component with a longitudinal slot. This integration eliminates the need for multiple separate parts, reducing device complexity and the number of components that require assembly and maintenance
Solution Approach 2:
The invention extracts and eliminates unnecessary intermediate components (lock links and pin joints) by directly integrating their locking and alignment functions into the tubular spring structure itself, simplifying the overall mechanism
3Ease of operation
If a conventional actuator with pin joints is used to fold the tube, then the folding function is achieved, but the weight and envelope of the assembly increases
Solution Approach 1:
The patent replaces the conventional mechanical actuator with pin joints with a flexible vessel actuator that uses fluid pressure to achieve folding. This substitution eliminates the need for complex mechanical linkages and pin joints in the actuator, reducing weight while maintaining the folding capability
Solution Approach 2:
The invention uses a flexible vessel actuator operated by pressurized fluid (pneumatics or hydraulics) to fold the tubular spring. This approach replaces heavy mechanical actuators with lighter fluid-powered actuation, reducing overall assembly weight while achieving the required folding function
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
This solution results in a lighter, simpler, and more reliable landing gear assembly with fewer components, reducing wear and maintenance needs while maintaining the ability to efficiently transition between deployed and stowed conditions.
Implementation Method 1
which includes a lateral, flexible first portion or gallery which straightens due to an increase in internal fluid pressure
Implementation Method 2
a flexible vessel that can fold with the tube when the tube is in the tubular condition and which includes a lateral, flexible first portion or gallery which straightens due to an increase in internal fluid pressure
Data Source
Figure 1~2c
Figure 3a~4a
Figure 4b~5
AI summary
An aircraft landing gear assembly (10) includes a bi-stable, split line tube (22) biased to assume a tubular condition to serve in place of a lock link or side stay and a flexible vessel actuator configured to radially enlarge the tube at a region for folding.