Landing Gear Spring Anchor Dynamics
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Solution Overview
Problem
Large aircraft landing gear assemblies require heavy and difficult-to-manufacture down locking springs to meet load requirements, which are inefficient and challenging to design effectively.
Innovation Solution
Incorporating a lost motion assembly with a rod and shackle mechanism into the down locking mechanism of the landing gear assembly, allowing for reduced spring extension and enabling the use of smaller, lighter springs by varying the distance between anchor points as the gear moves between deployed and stowed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If large down locking springs are used to meet load requirements on larger aircraft, then the load-bearing capacity is sufficient, but the springs become undesirably heavy and difficult to manufacture
Solution Approach 1:
The patent applies the dynamics principle by making the spring anchor point movable rather than fixed. The lost motion assembly allows the spring's effective attachment point to shift position along the stay assembly, enabling the spring to maintain optimal load-bearing capacity while using smaller, lighter wire diameters. This dynamic adjustment of the anchor point position allows the spring to adapt its mechanical advantage throughout the landing gear's movement range.
Solution Approach 2:
The patent implements parameter changes by varying the distance between the spring anchor point and other critical points on the stay assembly. Through the lost motion assembly, the spring's effective length and attachment position are changed dynamically, allowing the same spring to provide adequate load-bearing capacity across different operational states while reducing overall spring size and weight requirements.
2Strength
If large down locking springs are used to meet load requirements, then the mechanical strength is sufficient, but manufacturing difficulty increases
Solution Approach 1:
By introducing a movable anchor point through the lost motion assembly, the system dynamically adjusts the spring's mechanical characteristics. This allows smaller springs with more manageable wire diameters to be used, which are easier to manufacture while still achieving the required strength through optimized dynamic leverage rather than relying on oversized static components.
Solution Approach 2:
The patent changes the operational parameters of the spring system by allowing variable anchor point position. This enables the use of smaller springs that are more manufacturable, as the dynamic parameter adjustment compensates for the reduced spring size, maintaining adequate strength while improving ease of manufacture.
3Device complexity
If fixed anchor points are used for down locking springs, then the structure is simple, but larger springs are required which are heavier and more difficult to manufacture
Solution Approach 1:
The lost motion assembly acts as an intermediary mechanism between the spring and the stay assembly. Rather than directly attaching the spring to a fixed point, the intermediary lost motion assembly enables dynamic anchor point positioning. This adds controlled complexity to the structure while significantly reducing spring weight, as the intermediary mechanism allows smaller springs to achieve the same functional效果 through dynamic adjustment.
Data Source
AI summary
A landing gear assembly having a first part movable relative to a second part, and a spring coupled to the first and second parts via first and second anchor points. A lost motion assembly is provided to enable one of the anchor points to translate along one of the parts. As such, the spring extends less as the first part moves relative to the second part than it would if each anchor point was fixed to a respective part.