Thrust Reverser Cowl Locking Mechanism for O-Duct Turbojet

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Solution Overview

Problem

O-duct turbojet engines lack a third safety lock, compromising their reliability and security compared to D-duct engines, which are more secure due to the presence of an independent third lock.

Innovation Solution

Incorporating a mechanically and geographically independent locking mechanism between the cowl and pylon, featuring a lock body with a keeper and bolt, allowing for a third safety lock installation without special adaptations, and providing electrical supply cables with excess length for connectivity during sliding, along with offset rails for maintenance access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a one-piece cowl is used in an O-duct reverser, then the structure is simpler and manufacturing is easier, but a third safety lock cannot be installed, reducing reliability

Engineering Contradiction:
Improveease of manufactureVSAvoidreliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The locking means is segmented into distinct components: a lock body with a keeper articulated on it, and a separate bolt. This segmentation allows the locking mechanism to be installed in the limited space between the pylon and cowl while maintaining the simplicity of the one-piece cowl structure, thereby preserving ease of manufacture while enabling the installation of a third safety lock to improve reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lock body is mounted inside the pylon, with the keeper passing through an orifice in the pylon. This nested arrangement allows the locking mechanism to be integrated within the existing structure without requiring additional external space, thus maintaining the simplicity of the one-piece cowl design while adding the necessary safety lock functionality

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If safety locks are provided with independent power sources, then reliability and security are increased, but device complexity increases

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking means uses a universal bolt that can be integral with either the cowl or the pylon, and the lock body can be mounted in either component. This multi-functional design allows the same basic locking mechanism to serve multiple purposes and be configured differently based on specific installation requirements, reducing overall device complexity while maintaining reliability through independent power sources

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the lock body is mounted inside the pylon with the keeper passing through an orifice, then space is efficiently used and installation is simplified, but the pylon structure must be modified

Engineering Contradiction:
Improveease of installationVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

An orifice is formed in the pylon during the manufacturing process to accommodate the keeper. This preliminary action ensures that the locking mechanism can be easily installed without requiring complex post-manufacturing modifications, thereby simplifying installation while maintaining a relatively simple overall structure

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2504554B1Unit for turboreactor comprising thrust reverser cowlings
Publication Date: 2015.09.09 AIRCELLE SA
  • EP2504554B1 patent drawingFigure 1~3
  • EP2504554B1 patent drawingFigure 4~6
  • EP2504554B1 patent drawingFigure 7~9

AI summary

The invention relates to an assembly for a turbojet engine which includes a pylon (1) and a nacelle supported by said pylon (1). Said nacelle (3) includes a grid thrust reverser (21) including an integral cowl mounted so as to slide on rails (15), which are arranged on both sides of said pylon (1), between a direct jet position and a thrust reversal position. Said assembly is characterised in that it includes means (23, 31) for blocking the sliding movement of the cowl on the rails (15), said means being inserted between the pylon (1) and the cowl.