Thrust Reverser Lockout Mechanism for Automated Maintenance Safety
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Solution Overview
Problem
Current thrust reverser actuation systems in aircraft engines require manual inhibition of movable parts during maintenance for safety, which can be cumbersome and lacks automated safety features.
Innovation Solution
A hydraulic actuator system with a lockout mechanism that includes a synchronization mechanism and a lockout mechanism with a handle-operated lockout mechanism, allowing for safe inhibition and automatic release of the thrust reverser movement, ensuring crew safety during maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual inhibition of movable parts is used during maintenance, then safety is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The system automatically inhibits thrust reverser movement during maintenance by detecting when the engine service door is open, eliminating the need for manual intervention. The automatic lockout mechanism engages when the door opens and disengages when the door closes, allowing the system to serve itself without requiring crew members to manually inhibit movable parts.
Solution Approach 2:
The system uses the position of the engine service door as a feedback signal to control the lockout mechanism. When the door is open, the system receives feedback that maintenance is in progress and automatically engages the lockout. When the door closes, the feedback indicates maintenance is complete and the lockout disengages, creating a closed-loop safety system.
2Reliability
If manual inhibition of movable parts is used during maintenance, then safety is improved, but ease of operation worsens
Solution Approach 1:
The system automatically inhibits thrust reverser movement during maintenance by detecting when the engine service door is open, eliminating the need for manual intervention. The automatic lockout mechanism engages when the door opens and disengages when the door closes, allowing the system to serve itself without requiring crew members to manually inhibit movable parts.
Solution Approach 2:
The system uses the position of the engine service door as a feedback signal to control the lockout mechanism. When the door is open, the system receives feedback that maintenance is in progress and automatically engages the lockout. When the door closes, the feedback indicates maintenance is complete and the lockout disengages, creating a closed-loop safety system.
3Reliability
If lockout mechanism is added to inhibit movement, then safety is improved, but weight and installation impact worsen
Solution Approach 1:
The lockout mechanism is integrated into the existing hydraulic actuator system, allowing the actuator to serve dual functions: normal thrust reverser operation and maintenance lockout. By making the actuator multi-functional, the patent avoids adding separate dedicated lockout hardware that would increase weight and installation complexity.
Solution Approach 2:
The patent combines the lockout mechanism with the existing hydraulic actuator components, merging the safety function into the operational system. The lockout pins, actuator housing, and hydraulic components work together as an integrated system rather than separate additions, minimizing overall weight and installation impact.
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 inhibits thrust reverser movement for safety during maintenance while minimizing weight and installation impact, providing enhanced safety with automatic unlocking upon door closure.
Implementation Method 1
A piston is axially movable within the cylinder and is coupled with a lead screw to move the end assembly into and out of the extended position. The piston and cylinder are fluidly connected with a hydraulic supply line and a hydraulic return line.
Implementation Method 2
A piston is axially movable within the cylinder and is coupled with a lead screw to move the end assembly into and out of the extended position.
Implementation Method 3
A synchronization mechanism is operably coupled to the lead screw of each actuator to synchronize the multiple actuators.
Implementation Method 4
The lockout mechanism includes a piston movable within the actuator housing between a first position, corresponding to the permit condition, and a second position corresponding to the inhibit condition. When in the inhibit condition, the lockout mechanism prevents rotation of the lead screw.
Data Source
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AI summary
A turbofan engine having a thrust reverser having at least one movable control surface, movable to and from a reversing position where at least a portion of the bypass air flow is at least partially reversed, a thrust reverser actuation system having multiple actuators and a lockout mechanism movable between an inhibit condition, wherein movement of the multiple actuators is prevented, and a permit condition, wherein movement of the multiple actuators is permitted.