Aircraft Sliding Door Locking Mechanism Redundancy

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Solution Overview

Problem

Existing aircraft door locking mechanisms are complex, lack redundant systems, and require immediate intervention during malfunctions, leading to increased maintenance times and difficulties in procedures.

Innovation Solution

A simpler locking mechanism using a hook mechanism with a push-pull cable and elastic elements that allows automatic locking and release of sliding passenger doors without lifting, incorporating a redundant locking system for reliability and lighter components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a complex locking mechanism is used to ensure door security, then reliability is improved, but device complexity increases and maintenance difficulty worsens

Engineering Contradiction:
Improvedoor locking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is divided into separate functional components: a primary locking system with cam and latch, and a secondary redundant locking system with independent latch. This segmentation allows each component to be simpler while maintaining overall reliability through the combination of multiple independent systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A redundant locking system is incorporated as a backup mechanism that automatically engages if the primary locking system fails. This beforehand cushioning ensures door security is maintained even when the primary system malfunctions, resolving the contradiction between reliability and complexity by providing fail-safe protection.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a redundant locking mechanism is added to prevent immediate intervention during malfunction, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvedoor locking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent incorporates a redundant locking system with independent latch and cam mechanisms that automatically engage if the primary locking system fails. This beforehand cushioning provides fail-safe protection without requiring complex control systems, as the redundancy is achieved through mechanically independent parallel systems.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The redundant locking system uses simpler, more robust mechanical components that can be easily replaced if needed. Rather than using complex electronic or programmable systems, the patent employs durable mechanical redundancy that prioritizes simplicity and replaceability over long component life.

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

3Reliability

If the door locking mechanism uses heavier components for stability, then reliability is improved, but weight of moving object increases

Engineering Contradiction:
Improvedoor locking reliabilityVSAvoiddoor mechanism weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs cam mechanisms that use the door's own weight and gravitational force to assist the locking action. The cam geometry is designed so that the door's weight provides a mechanical advantage, reducing the force and weight of additional components needed to achieve reliable locking.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The cam mechanisms use curved surfaces and spherical contact points to distribute loads and reduce stress concentrations. This curvature allows for lighter components while maintaining structural integrity and locking reliability, as the distributed contact areas reduce the need for heavily reinforced parts.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Device complexity

If a manual handle locking system is used, then device complexity is reduced, but ease of operation worsens during emergencies

Engineering Contradiction:
Improvelocking mechanism complexityVSAvoiddoor release ease
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to automatically lock when the door reaches the fully open position through the cam and latch geometry. This self-service locking eliminates the need for manual intervention during normal operation, while the separate manual handle provides direct mechanical access to the latch for emergency release without requiring complex electronic systems.

Inventive Principle:
Principle #25Self-service

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

Enables safe and efficient locking and release of aircraft doors in open positions during flight or parking, reducing maintenance needs and ensuring door stability even in case of component failures, with improved operational efficiency and reduced power requirements.

Implementation Method 1

at least an elastic element (7) which forces said hook mechanism (6) to stay inside said guide rail (R)

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP2872395B1Aircraft comprising a sliding door with a locking mechanism
Publication Date: 2016.10.05 TUSAS TURK HAVACILIK VE UZAY SANAYII
  • EP2872395B1 patent drawingFigure 1
  • EP2872395B1 patent drawingFigure 2
  • EP2872395B1 patent drawingFigure 3

AI summary

The present invention relates to a locking mechanism (1) that provides for the door moving inside a guide rail in aircrafts to stay safely at an open position and released during a flight or when the aircraft is parked. Said mechanism (1) which enables the doors of aircrafts to be slid upwards and to be locked at a predetermined position, provides the door to be locked at a fully open position and to be suspended and released when desired.