Aircraft Nacelle Locking System With Load-Sensed Closure Detection

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Solution Overview

Problem

Existing locking systems for aircraft nacelles are difficult to inspect and prone to being left in the open position during flight due to their location and complexity, leading to potential cover opening in flight, and existing solutions involve significant mass and cost additions.

Innovation Solution

A locking system with a load sensor integrated between buffer parts and hook housings that generates a signal when a threshold load is exceeded, allowing detection of the closed position, and includes a pivot-sliding connection to ensure no load is exerted in the open position, minimizing mass and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If locking systems are positioned at the bottom of the nacelle near the ground, then the structural design is simplified, but the locking systems become difficult to inspect and may be left in the open position

Engineering Contradiction:
Improvestructural designVSAvoidinspection difficulty
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

A load sensor is introduced as an intermediary device between the buffer part and hook housing to detect the closed position of the locking system. The sensor provides indirect measurement of the locking state through load detection, enabling remote monitoring without requiring direct visual inspection of the locking mechanism at the bottom of the nacelle.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mechanical inspection process is replaced by an automated sensing system. Instead of requiring visual or physical inspection of the locking mechanism, the load sensor converts the mechanical locking state into an electrical signal that can be detected and transmitted, eliminating the need for direct human inspection at difficult-to-reach locations.

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

2Reliability

If inductive sensors or force sensors are integrated into the locking system to detect closed position, then the reliability of cover closure is improved, but the mass and cost of the locking system increase significantly

Engineering Contradiction:
Improvecover closure reliabilityVSAvoidlocking system mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs a load sensor that is relatively simple and cost-effective compared to complex inductive or force sensors. The sensor is positioned to detect load changes during the locking process, providing reliable closure detection without requiring expensive sophisticated sensing mechanisms, thus balancing reliability with mass and cost constraints.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The detection method relies on monitoring changes in load parameter rather than using complex sensor systems. By detecting the threshold load that occurs when the hook engages the latch, the system achieves reliable closure detection through a simple parameter measurement approach, avoiding the need for massively complex or expensive sensing technology.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If oversized locking systems are used to compensate for possible failure, then the safety margin is improved, but the mass and complexity of the locking system increase

Engineering Contradiction:
Improvesafety marginVSAvoidlocking system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The load sensor provides feedback about the actual locking state to the control system. This feedback mechanism allows the system to verify that the locking system is properly engaged without requiring oversized components. The feedback enables precise control and monitoring, replacing the need for excessive safety margins with intelligent monitoring and control.

Inventive Principle:
Principle #23Feedback

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

The system effectively detects the closed position of aircraft nacelle covers during flight, reducing the risk of accidental opening and minimizing additional mass and cost, while being easy to integrate into existing systems.

Implementation Method 1

a load sensor (817) which is attached to the first buffer part (815) and positioned so as to be compressed between this buffer part (815) and the hook housing (807) when the locking system (801) is in the closed position

Methodology Applied
Scientific EffectLoad sensing:

Implementation Method 2

the buffer part (815) is connected to the hook housing (807) by a pivot-sliding type connection with a fixing clearance J which is adapted to allow the buffer part (815) to slide in the hook housing (807)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4363319B1Locking system for an aircraft nacelle
Publication Date: 2025.08.06 SAFRAN NACELLES
  • EP4363319B1 patent drawingFigure 1a~1b
  • EP4363319B1 patent drawingFigure 2~3
  • EP4363319B1 patent drawingFigure 4~5

AI summary

The invention relates to a locking system (801) for an aircraft nacelle comprising a first portion (803), intended to be mounted on a first part (703) of an aircraft nacelle, and a second portion (809), intended to be mounted on a second part (709) of the aircraft nacelle. The locking system (801) is configured such that, when it is in the closed position, the first portion (803) and the second portion (809) are held together. It comprises at least one buffer part (815) and a load sensor (817) joined together and configured to compress the load sensor (817) between the buffer part (815) and another part (807) of the locking system (801) when it is in the closed position.