Aircraft Thrust Reverser Door Closing System Rod Breakage Detection

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Solution Overview

Problem

Existing door thrust reverser systems for aircraft nacelles lack a reliable method to detect connecting rod breakages, leading to asymmetric force transmission and potential operational failures during numerous operating cycles.

Innovation Solution

A door closing system with two first connecting rods and two sliding members, equipped with a detection device that compares the relative positions of the sliding members to detect breakages, and an active locking system to secure doors in the closed position when no breakage is detected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If connecting rods are used to transmit forces from doors to fixed structure during numerous operating cycles, then the door thrust reverser system achieves reliable force transmission, but the risk of undetected connecting rod breakage and asymmetric force transmission increases

Engineering Contradiction:
Improveforce transmission reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism by using sensors to detect the position of sliding members and comparing it with the expected position. When a discrepancy is detected, it indicates a connecting rod breakage, and the system provides feedback to the control unit to prevent further operation. This closes the loop between the mechanical system and the control system, enabling real-time monitoring and detection of failures.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces sliding members as intermediary elements between the connecting rods and the fixed structure. These sliding members serve as mediators that translate the mechanical state of the connecting rods into detectable positional information. The sensors detect the position of these intermediaries, indirectly monitoring the integrity of the connecting rods without directly interfering with the force transmission function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a detection device is added to monitor connecting rod integrity, then the reliability of the door thrust reverser system is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveconnecting rod breakage detectionVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses the existing moving parts (doors and sliding members) to indicate their own state. When a connecting rod breaks, the door cannot return to its proper closed position, and the sliding member's position automatically reflects this fault condition. The system essentially monitors itself through the positional information already present in its operational state, without requiring complex additional sensing mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical monitoring mechanisms with simpler electronic sensors and a control unit. Instead of using complex mechanical linkages or switches to detect breakages, the system uses position sensors to detect the location of sliding members and processes this information electronically. This substitution reduces mechanical complexity while improving detection reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the door closing system uses single-acting or double-acting cylinders with connecting rods, then the door operation is simplified, but the ability to detect connecting rod breakages is lost

Engineering Contradiction:
Improvedoor operation simplicityVSAvoidbreakage detection capability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent maintains the dynamic simplicity of single- or double-acting cylinders for door operation while adding a static monitoring component (sensors detecting sliding member position). The dynamic mechanical system remains unchanged and simple, but a static detection system is superimposed on it. This allows the operational simplicity to be preserved while adding detection capability through a separate, non-intrusive monitoring layer.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3924611B1Door-closing system for a thrust reverser of an aircraft nacelle
Publication Date: 2024.01.03 SAFRAN NACELLES
  • EP3924611B1 patent drawingFigure 1~2
  • EP3924611B1 patent drawingFigure 3~4
  • EP3924611B1 patent drawingFigure 5~6

AI summary

The invention relates to a closing system of a pair of doors (12a, 12b) for a thrust reverser (10) of an aircraft nacelle, the doors being pivotably mounted between a direct-jet position and a reverse-jet position, the closing system comprising: - a closing actuator (15) comprising two first connecting rods (16a, 16b), each connected to a first side edge (120a, 120b) of each door, said actuator being arranged to manoeuvre each door towards the direct-jet position, - two sliding members (22a, 22b) each carrying a second connecting rod (18a, 18b) connected to the opposite side edge (121a, 121b), said connecting rods being arranged to be driven by the doors, so as to move the sliding members, and - a device (19) for detecting the breaking of a connecting rod arranged to detect the relative position of the sliding members in direct-jet position.