Turbojet Thrust Reverser Cowl Locking Mechanism Pylon Integrity
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Solution Overview
Problem
The existing thrust reverser systems for turbojet engines require dismounting a hatch for maintenance, which increases access time and compromises the structural strength of the pylon, as they lack a tertiary lock that can be manually inhibited from outside without affecting the pylon's integrity.
Innovation Solution
A locking/unlocking device with a switching rocker and actuating means, including a push button/pusher assembly and spring-loaded balls, allows for rapid mode switching between operational and maintenance modes without dismounting the hatch, ensuring the reverser cowl remains secure during flight and facilitating easier maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hatch is provided in the pylon for accessing the locking device, then maintenance access is enabled, but the structural strength of the pylon is compromised
Solution Approach 1:
The locking device is extracted from the pylon structure and mounted on the cowl itself. The locking means are now part of the cowl assembly rather than being integrated into the pylon, eliminating the need for a hatch in the pylon while maintaining maintenance accessibility from the bypass flow duct side
Solution Approach 2:
The cowl acts as an intermediary carrier for the locking device. Instead of mounting locking means directly on the pylon, they are mounted on the cowl which can be accessed from the bypass flow duct, serving as a mediator between the maintenance access requirement and the pylon structural integrity
2Reliability
If the locking device is mounted inside the pylon, then it provides secure locking, but maintenance requires time-consuming hatch disassembly
Solution Approach 1:
The locking device is extracted from the pylon interior and relocated to the cowl assembly. This allows maintenance personnel to access and operate the locking device from the bypass flow duct side without needing to disassemble the pylon hatch, significantly reducing maintenance access time while maintaining locking functionality
Solution Approach 2:
The cowl assembly with integrated locking means can be accessed and maintained from the bypass flow duct side, allowing the system to serve its own maintenance needs without requiring complex disassembly procedures. The locking device is positioned where it can be serviced during normal cowl access operations
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
This solution reduces access time to the engine, enhances the structural integrity of the pylon, and provides visual confirmation of the locking status, eliminating the need for hatch disassembly and ensuring the reverser cowl remains secure during flight operations.
Implementation Method 1
spring-loaded balls, allows for rapid mode switching between operational and maintenance modes
Data Source
AI summary
An assembly for a turbojet engine includes a pylon, a nacelle supported by the pylon, and a locking device interposed between the pylon and a cowl of the nacelle. The cowl slides between operating and maintenance positions. The locking device is movable between active and inhibited positions, and the device allows an operation mode in the active position and a maintenance mode in the inhibited position. In particular, the locking device comprises a rocker to maintain the cowl to the pylon, and the rocker includes an inhibiting lever and an activation lever. The inhibiting and activation levers are mounted on a switching shaft of the locking device. The inhibiting lever is set in rotation through an actuator, providing direct access from a bypass flow duct in the active position while the activation lever is set in rotation from the bypass duct in the inhibited position.