SMA Pawl Locking Apparatus Reducing Component Complexity
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Solution Overview
Problem
Existing locking apparatuses for structures, such as aircraft doors, are complex and include redundant components, leading to increased design, installation time, and manufacturing costs, and often require more components than necessary for reliable locking and unlocking.
Innovation Solution
A locking apparatus utilizing a shape memory alloy (SMA) pawl that transitions between locked and unlocked positions based on thermal activation and deactivation, reducing the number of moving components and incorporating a support assembly to simplify the locking mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing locking apparatuses use complex arrangements of components (solenoids, electric motors, bearings, springs, weights, and screw gears), then reliable locking and unlocking can be achieved, but the device complexity increases and more components are required
Solution Approach 1:
The patent extracts and eliminates redundant components from traditional locking mechanisms. By using a shape memory alloy (SMA) element as the core actuating component, the design removes the need for solenoids, electric motors, bearings, springs, weights, and screw gears, achieving reliable locking/unlocking with a single intelligent material element that performs multiple functions
Solution Approach 2:
The invention utilizes parameter changes in the shape memory alloy material - specifically its ability to change shape in response to temperature changes. The SMA element transitions between different shapes when heated or cooled, enabling the locking and unlocking functions through thermal parameter changes rather than complex mechanical actuation
2Reliability
If existing locking actuators include redundant components to return doors to unlocked state after power removal, then safety and reliability are improved, but the quantity of components increases
Solution Approach 1:
The shape memory alloy element provides self-service functionality by automatically returning to its original shape when cooled. The SMA inherently possesses the ability to revert to its programmed shape upon temperature reduction, eliminating the need for separate return-spring mechanisms or additional actuators to restore the unlocked state
Solution Approach 2:
The invention employs shape memory alloy, an intelligent composite material that combines elastic and shape memory properties in a single element. This material integrates multiple functions (actuation, positioning, and return) that traditionally required separate components, reducing the total quantity of parts while maintaining reliability
3Reliability
If existing locking apparatuses contain more components than desired, then reliable locking can be achieved, but design and installation time increases
Solution Approach 1:
By extracting and removing unnecessary components from the locking system, the patent significantly reduces assembly complexity. The SMA-based design requires fewer parts to be designed, sourced, and installed, directly reducing design and installation time while preserving the essential locking function through the intelligent material's inherent capabilities
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 SMA-based locking apparatus provides a reliable, efficient, and cost-effective solution for locking and unlocking structures with fewer components, ensuring quick transition to the unlocked position in emergency scenarios and offering higher locking/unlocking forces for enhanced resistance against jamming.
Implementation Method 1
The pawl includes a shape memory alloy (SMA) element configured to transition between a first configuration and a second configuration
Implementation Method 2
activating the SMA element, thereby causing the SMA element to take on the first configuration and move the second end of the pawl to the locked position, and deactivating the SMA element, thereby causing the SMA element to take on the second configuration and move the second end of the pawl from the locked position to the unlocked position
Data Source
AI summary
In an example, method for locking/unlocking a structure is described. The method includes attaching a first end of a pawl to a support assembly, wherein the pawl comprises a shape memory alloy (SMA) element configured to transition between a first configuration and a second configuration, and wherein the pawl is attached to the support assembly such that a second end of the pawl is movable between a locked position that prevents a rotatable shaft from rotating and an unlocked position that allows the rotatable shaft to rotate, activating the SMA element, thereby causing the SMA element to take on the first configuration and move the second end of the pawl to the locked position, and deactivating the SMA element, thereby causing the SMA element to take on the second configuration and move the second end of the pawl from the locked position to the unlocked position.