Aircraft Check Valve Leaf Spring Stop Damping
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Solution Overview
Problem
Existing check valves in aircraft applications face issues with high-velocity flapper impacts on stop pins, leading to costly and time-consuming part replacements due to the need for robust and heavy components to withstand impact forces.
Innovation Solution
The use of modified leaf spring stop elements with diverging or parallel surfaces, U-shaped, C-shaped, or D-shaped designs, and resilient damping elements like coil or elastomer springs to absorb energy and reduce the impact force on stop elements, allowing flappers to open at higher velocities without damaging the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robust stop pins are used to withstand impact forces, then reliability is improved, but weight increases
Solution Approach 1:
The patent introduces a resilient element (spring or elastomer) positioned between the flapper and stop pin that absorbs impact energy before it reaches the stop pin. This cushioning mechanism allows the stop pin to be lighter while still protecting the system from damage during high-velocity flapper opening.
Solution Approach 2:
The resilient element acts as an intermediary between the flapper and stop pin, mediating the impact force. Instead of the flapper directly impacting the stop pin, the resilient element intermediate structure absorbs and dissipates the shock, enabling weight reduction of the stop pin while maintaining reliability.
2Strength
If heavy stop pins are used to withstand impact forces, then strength is improved, but manufacturing cost increases
Solution Approach 1:
By incorporating a resilient element that cushions the impact beforehand, the stop pin no longer needs to be heavily constructed to withstand full impact forces. This allows for a lighter, less expensive stop pin design while maintaining the required strength through the combined system of resilient element plus stop pin.
Solution Approach 2:
The resilient element serves as an intermediary that reduces the peak impact force transmitted to the stop pin, allowing the stop pin to be manufactured with less material and lower cost while still providing adequate strength for its reduced load requirements.
3Reliability
If robust components are used to withstand impact forces, then reliability is improved, but device complexity increases
Solution Approach 1:
The resilient element provides beforehand cushioning that protects the stop pin and other components from damage. This simple addition of a cushioning element improves reliability without requiring complex structural modifications to the stop pin itself, maintaining design simplicity while enhancing durability.
Solution Approach 2:
The resilient element acts as a simple intermediary component that absorbs impact energy, protecting the stop pin and other components from damage. This approach improves reliability through a single additional element rather than through complex structural designs, minimizing the increase in device complexity.
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 modified stop elements enable flappers to open at higher velocities while minimizing damage and weight, improving valve lifespan and reducing maintenance costs by dissipating energy during impacts and providing improved stress distribution and manufacturing efficiency.
Implementation Method 1
at least one resilient damping element mounted between opposed facing surfaces of the stop portions of the stop elements
Implementation Method 2
resilient damping element may be a coil spring or an elastomer spring to absorb energy and reduce the impact force
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A check valve (2) comprises a valve housing (4) defining a pair of valve openings (6), a pair of mounting posts (10) arranged on opposed sides of the valve housing (4), a hinge pin (12) mounted between said mounting posts (10), a pair of flapper elements (14) pivotably mounted to the one or more hinge pins (12) for rotation relative to the housing (4) between an open position in which they permit fluid flow through the respective valve openings (6) and a closed position in which they prevent fluid flow through the valve openings (6). A pair of elastically deformable leaf spring stop elements (30), each of which comprise respective end portions (32) that are mounted to, and extend upwardly from, said mounting posts (10) and a stop portion (34) arching upwardly from, and extending between said end portions (32), such that each flapper element (14) will engage a respective surface of said stop portion (34) when in the open position.