Thrust Reverser Inhibition Pin Locking System

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Solution Overview

Problem

Current thrust reverser devices for aircraft turbofan nacelles require complex and time-consuming installation of mechanical inhibition devices to prevent deployment during flight, which involves storing and manually installing pins or screws, making the process cumbersome and costly.

Innovation Solution

A mechanical inhibition device that directly acts on the locking/unlocking system of the thrust reverser, using an inhibition pin or screw to maintain the locking/unlocking system in its closed position, preventing deployment both in flight and on the ground, thereby simplifying installation and reducing maintenance time and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical inhibition device is installed using traditional methods (storing and manually installing pins or screws), then the thrust reverser can be inhibited during flight, but the installation process becomes complex and time-consuming

Engineering Contradiction:
Improveinhibition reliabilityVSAvoidinstallation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The inhibition device is divided into separate modular components (inhibition pin, strike plate, guide features) that can be independently manufactured and assembled. The pin and strike plate are distinct elements that work together, allowing for simplified installation where components are pre-positioned with guide features rather than requiring complex manual assembly procedures

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inhibition device incorporates guide features (such as guide pins or alignment slots) that automatically position the inhibition pin and strike plate correctly during installation. This self-aligning mechanism eliminates the need for complex manual positioning and reduces installation time while ensuring proper alignment and reliable inhibition

Inventive Principle:
Principle #25Self-service

2Reliability

If a mechanical inhibition device is installed using traditional methods, then deployment prevention is achieved, but the device complexity increases

Engineering Contradiction:
Improvedeployment safetyVSAvoidinhibition device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inhibition functionality is extracted as a separate, simple mechanical device (pin and strike plate assembly) rather than being integrated into the complex locking/unlocking system. This standalone inhibition device can be easily installed and removed without affecting the main thrust reverser mechanism, reducing overall system complexity while maintaining safety

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The inhibition pin and strike plate design uses universal geometric features (cylindrical pins, flat surfaces, guide slots) that can be applied to various thrust reverser configurations. This standardized approach reduces device complexity by using common mechanical elements rather than custom-designed complex inhibition mechanisms

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

3Reliability

If traditional inhibition methods are used requiring stored pins or screws, then inhibition functionality is provided, but ease of operation deteriorates

Engineering Contradiction:
Improveinhibition functionalityVSAvoidinstallation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The inhibition pin and strike plate are pre-assembled with guide features during manufacturing, creating a pre-configured inhibition unit. This preliminary preparation allows for quick installation where the pre-assembled unit is simply positioned and secured, eliminating the need for technicians to manually handle and assemble multiple small components during maintenance operations

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2971730B1Mechanical inhibiting device integrated into a defence line of a thrust reverser
Publication Date: 2020.04.29 SAFRAN NACELLES
  • EP2971730B1 patent drawingFigure 1~2
  • EP2971730B1 patent drawingFigure 3~5
  • EP2971730B1 patent drawingFigure 6~8

AI summary

The present disclosure provides a thrust reverser device for a nacelle of a by-pass turbojet engine, including: a cowl moving alternately between a deployed position in which the cowl opens a passage within the nacelle and a retracted position in which the cowl closes the passage; a locking/unlocking system to lock and unlock the cowl, the locking/unlocking system moving alternately between a closed position in which a bolt cooperates with a striker so as to hold the cowl in the retracted position, and an open position in which the bolt releases the striker, so as to allow a switching of the cowl from the retracted position to the deployed position; and a device for mechanically inhibiting the cowl from a movement, holding in the retracted position. In particular, the mechanical inhibition device holds the locking/unlocking system in the closed position.