Turbojet Thrust Reverser Locking Mechanism
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Solution Overview
Problem
Existing thrust reverser systems for turbojet engines require complex and heavy locking mechanisms with multiple electrical and mechanical components, which can lead to weight issues and increased risk during maintenance and flight operations.
Innovation Solution
A lighter and more robust locking system for movable cowls, utilizing a first and second locking element with a path diverting device that allows controlled displacement for unlocking, eliminating the need for electrical actuators and detectors, and incorporating a safety device to prevent uncontrolled reclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex locking mechanisms with multiple electrical and mechanical components are used, then the thrust reverser system can be securely locked, but the weight and complexity of the system increases
Solution Approach 1:
The patent removes electrical actuators, detectors, and complex control systems from the locking mechanism, extracting only the essential mechanical locking function. The locking system uses simple mechanical elements (locking pins, springs, and geometric constraints) that can be passively engaged and disengaged through the natural movement of the cowl, eliminating heavy electrical components while maintaining secure locking.
Solution Approach 2:
The locking system is designed to be self-actuating through the cowl's own movement. When the cowl is closed, geometric constraints and spring forces automatically engage the locking pins with the locking surfaces. When the cowl opens, the same movement automatically disengages the locks. This self-service mechanism eliminates the need for external electrical actuators and complex control systems, significantly reducing weight and complexity.
2Ease of operation
If electrical actuators and detectors are used for locking and unlocking, then precise control is achieved, but the system complexity and weight increase
Solution Approach 1:
The patent replaces electrical actuators and detectors with a purely mechanical system. The locking control is achieved through the geometric relationship between moving and fixed parts of the cowl. As the cowl moves between closed and open positions, mechanical cam surfaces and guide rails automatically control the engagement and disengagement of locking pins, eliminating electrical components while maintaining precise control through mechanical geometry.
Solution Approach 2:
Instead of using electrical actuators to actively engage locks and detectors to monitor position, the system inverts the approach: the natural opening movement of the cowl automatically disengages the locks, and the closed position naturally engages them. This inversion eliminates the need for complex electrical control systems while achieving precise locking control through the inherent mechanics of cowl movement.
3Reliability
If mechanical inhibition systems are used to prevent unexpected opening, then safety during maintenance is improved, but the system becomes more complex
Solution Approach 1:
The locking system is designed with preliminary anti-action by providing geometric constraints and spring-loaded locking pins that passively prevent the cowl from opening unless specific unlocking conditions are met. During maintenance, the locked position is maintained by the inherent mechanical geometry and spring forces, which actively resist any unexpected opening movement before maintenance personnel can even attempt to open the cowl, providing safety without additional complex inhibition systems.
Data Source
AI summary
The present disclosure concerns a thrust reverser system for a turbojet engine and a method for unlocking a thrust reverser system. The thrust reverser system includes a movable cowl mounted on a nacelle of the turbojet engine that is displaceable between a closed position in which the thrust reverser system is inactivated and an open position in which the thrust reverser system is activated. The thrust reverser system includes a locking system having a first and second locking element mounted on the movable cowl and a fixed structure. The first and second locking elements lock and unlock relative to each other to lock the movable cowl on the fixed structure in the closed position. The locking system is shaped so that a controlled displacement of the movable cowl from its closed position to a reclosed position triggers unlocking of the first and second locking elements.