Thrust Reverser Locking Apparatus Frangible Linkage Design
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Solution Overview
Problem
Existing thrust reverser systems for aircraft propulsion face challenges in preventing unintended deployment of the translating sleeve due to damage from projectile collisions within the rotor burst zone, particularly when the tertiary locking apparatus is located outside the burst zone, which can lead to reduced propulsion system thrust.
Innovation Solution
A locking apparatus is configured with a lock actuator and lock that are connected through a frangible linkage, allowing the lock to remain operational even if the actuator is damaged, ensuring the translating sleeve remains locked in place by using a lock actuator that can disengage from the lock when locked and engage when unlocked, with the lock positioned outside the rotor burst zone to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tertiary lock is positioned outside the rotor burst zone, then the lock is protected from projectile damage, but the actuator must be positioned within the burst zone which increases vulnerability to damage
Solution Approach 1:
The locking system is divided into two separate components: the lock mechanism positioned outside the rotor burst zone and the actuator positioned within the burst zone. This segmentation allows each component to be optimally positioned for its function while reducing overall system vulnerability.
Solution Approach 2:
A frangible linkage serves as an intermediary between the actuator and the lock. This linkage transmits the actuating force from the vulnerable actuator to the protected lock, while being designed to fail safely under extreme conditions, preventing damage propagation.
2Reliability
If the frangible linkage is designed to sever under extreme force, then damage propagation is prevented, but the linkage may fail under normal operational loads
Solution Approach 1:
The frangible linkage is pre-designed with a controlled weak point that will fail at a predetermined force threshold. This beforehand cushioning ensures that under extreme conditions, the linkage will sever to contain damage, while under normal operational loads, the safety factor prevents premature failure.
3Volume of moving object
If the lock actuator can disengage from the lock when locked and engage when unlocked, then the locking mechanism becomes more compact, but the engagement and disengagement control becomes more complex
Solution Approach 1:
The engagement mechanism is inverted from the conventional approach: instead of the actuator pushing the lock into engagement, the spring automatically engages the lock, and the actuator's role is reversed to disengage it by pulling. This inversion simplifies the engagement control while achieving compact dimensions.
Data Source
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AI summary
An assembly is provided for an aircraft propulsion system with an axial centerline. The assembly includes a translating sleeve (36), a sleeve actuator and a locking apparatus (58). The sleeve actuator is connected to the translating sleeve (36). The sleeve actuator is configured to move the translating sleeve (36) along the axial centerline between a stowed position and a deployed position. The locking apparatus (58) includes a lock (72) and a lock actuator (70). The lock (72) comprises a locking element (84). The lock actuator (70) is configured to move the locking element (84) between a locked position and an unlocked position. The locking element (84) is configured to lock the translating sleeve (36) in the stowed position when the locking element (84) is in the locked position. A first portion (72) of the locking apparatus (58) axially overlaps the sleeve actuator along the axial centerline. A second portion of the locking apparatus (58) does not axially overlap the sleeve actuator along the axial centerline.