Linear Actuator Finger Lock for Thrust Reverser Deployment Safety
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Solution Overview
Problem
Existing aircraft engine thrust reverser lock designs are heavy and mechanically complex, posing safety risks due to accidental or unintentional deployment, which can lead to injuries or catastrophic failures during ground maintenance or flight.
Innovation Solution
A lightweight and less complex thrust reverser lock system utilizing a linear actuator with a housing, lock carrier, and sleeve configuration, where a lock finger is extended or retracted via an electromechanical actuator to prevent accidental deployment, featuring a short lock load path and reduced fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotating jaws are used to engage a probe in the locking mechanism, then the locking function is achieved, but the weight and mechanical complexity increase
Solution Approach 1:
The patent replaces the traditional rotating jaws mechanism with a linear actuator system that uses a lock finger moving in a linear path. This substitution of mechanical rotation with linear motion simplifies the overall mechanism, reduces the number of moving parts, and decreases mechanical complexity while maintaining the locking function. The lock finger extends linearly to engage with the probe, eliminating the need for rotating components.
Solution Approach 2:
The locking mechanism is divided into distinct functional segments: the lock carrier that holds the lock finger, the sleeve that guides the lock finger's movement, and the linear actuator that provides the driving force. This segmentation allows each component to perform its specific function independently, simplifying the overall design and reducing mechanical complexity compared to an integrated rotating jaws system.
2Reliability
If rotating jaws are used to engage a probe in the locking mechanism, then the locking function is achieved, but the weight increases
Solution Approach 1:
The patent replaces the traditional rotating jaws mechanism with a linear actuator system that uses a lock finger moving in a linear path. This substitution of mechanical rotation with linear motion simplifies the overall mechanism, reduces the number of moving parts, and decreases mechanical complexity while maintaining the locking function. The lock finger extends linearly to engage with the probe, eliminating the need for rotating components.
Solution Approach 2:
The patent extracts and eliminates unnecessary rotating components from the locking mechanism, keeping only the essential elements needed for the locking function. By removing the rotating jaws and probe engagement mechanism, and replacing it with a simpler linear lock finger system, the overall weight of the locking mechanism is reduced while maintaining adequate locking capability.
3Device complexity
If a linear actuator with lock finger and sleeve configuration is used, then the mechanical complexity is reduced, but the reliability against accidental deployment must be maintained
Solution Approach 1:
The linear actuator system incorporates a lock finger that must be actively retracted before the thrust reverser can be deployed. This preliminary action of lock finger retraction serves as a safety interlock, ensuring that accidental deployment cannot occur unless the locking mechanism is deliberately disengaged. The system requires a deliberate sequence of operations, adding a layer of protection against inadvertent activation.
Solution Approach 2:
The sleeve acts as an intermediary component between the linear actuator and the lock finger, providing guidance and constraint to the lock finger's movement. This intermediary mechanism ensures that the lock finger moves precisely along its intended path and maintains proper engagement with the thrust reverser system, thereby maintaining reliability while using a simpler linear mechanism.
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 system effectively prevents accidental deployment of thrust reversers, reducing the risk of injuries and failures by providing a reliable and efficient locking mechanism that is less prone to mechanical failures and maintenance issues.
Implementation Method 1
a threaded shaft and a nut threadedly engaged upon the threaded shaft, wherein the nut is configured to urge axial movement of the lock carrier within the axial cavity
Implementation Method 2
a bias member configured to bias the lock finger away from the retracted configuration and toward the extended configuration
Implementation Method 3
a planetary gearbox assembly having a sun gear assembly configured to receive rotary motion from a rotary actuator, a collection of planet gears configured to be driven by the sun gear assembly
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a linear actuator lock apparatus having a housing having an inner surface defining an axial cavity having a first housing portion where the axial cavity has a first lateral size, a second housing portion having a second, larger lateral size, and a face from the first housing portion to the second housing portion, a lock assembly having a lock carrier configured for movement within the cavity between a first position and a position, and a lock finger affixed to and extending away from the lock carrier, where the second finger end is configured to contact the face when extended and fit within the first housing portion when retracted, and a sleeve configured to move between a position in which the lock finger is permitted to extend and a position configured to contact and retract the lock finger.