Parallel-Strut Landing Gear Stay With Integrated Uplock
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Solution Overview
Problem
Modern aircraft landing gear systems face challenges with folding stays, which lack the low volume requirements and aerodynamic benefits of telescopic stays while also being prone to moisture ingress and hidden parts that are difficult to inspect, and require separate locking mechanisms.
Innovation Solution
A landing gear stay with a set of struts moving parallel to each other, allowing for a variable length configuration that mimics telescopic stays' efficiency while avoiding moisture issues and hidden parts, featuring open structures for easy inspection and integrated locking mechanisms for reduced friction and simplified operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If telescopic stays are used, then volume demand is reduced, but moisture contamination and inspection difficulty increase
Solution Approach 1:
The stay is divided into multiple separate struts (first strut, second strut, third strut) that move independently parallel to each other, replacing the enclosed telescopic tube structure. This segmentation allows the struts to be open and accessible for inspection while achieving compact volume through coordinated movement, eliminating the moisture trapping issue of sealed telescopic joints.
Solution Approach 2:
Instead of telescopic struts moving along a single common axis (one-dimensional movement), the invention uses multiple struts moving parallel to each other in the same direction (multi-dimensional arrangement). This parallel arrangement reduces the swept volume compared to traditional folding stays while maintaining open structures that can be inspected, avoiding the moisture contamination problem of telescopic joints.
2Ease of operation
If folding stays are used, then inspection ease is improved, but volume demand increases
Solution Approach 1:
The stay is segmented into multiple independent struts that can be individually inspected, providing inspection ease similar to folding stays. The struts are arranged parallel to each other with spaces between them, allowing visual and physical access to all components without requiring disassembly, while the parallel movement mechanism keeps the overall volume demand low.
Solution Approach 2:
The struts dynamically move parallel to each other during extension and retraction, coordinating their movement to achieve compact configuration when retracted. This dynamic parallel movement allows the structure to adapt its volume based on operational state while maintaining inspection accessibility throughout the movement range.
3Adaptability or versatility
If telescopic stays with hydraulic actuators are used, then actuation function is integrated, but device complexity and mass increase
Solution Approach 1:
The hydraulic actuation function is extracted from the stay structure itself. Instead of using a telescopic stay that also serves as the actuator (integrated design), the invention separates the actuation mechanism from the stay structure, using independent actuators to move the parallel struts. This reduces the complexity and mass of the stay while maintaining the integrated actuation capability.
Solution Approach 2:
The parallel strut arrangement serves multiple functions: it provides the structural stay function, enables compact volume through parallel movement, maintains inspection accessibility, and works with separate actuators for reliable deployment. This multi-functional design achieves actuation integration without the complexity of telescopic-hydraulic combined structures.
Data Source
AI summary
A variable length stay for an aircraft landing gear is disclosed having first and second sets of struts lying on different longitudinal axes that enable the stay to extend and contract by movement of the struts parallel to their axes. The stay may be locked in its extended and retracted configurations thus providing downlock and uplock functions for the landing gear. The struts of the stay may have an open and easy to inspect structure, have low friction kinematics, and do not need to telescope within each other or lie on a single common axis.