Aircraft Door Rotary Link Decoupling Mechanism

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Solution Overview

Problem

Existing connecting mechanisms between aircraft doors and structures fail to provide precise guidance during opening and closing while minimizing mechanical action transmission between the aircraft frame and door, especially when the door is closed, due to residual transmission issues exacerbated by temperature and pressure changes.

Innovation Solution

A rotary link assembly with a shaft that translates and locks into a disengaged position, utilizing ball joints and adjustable support members to decouple the door from the arm, eliminating the need for elastomeric elements and maintaining stiffness for precise guidance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If elastomeric elements are used to decouple the door from the link mechanism, then the transmission of mechanical actions between the framework and the door is reduced, but the guiding precision during opening and closing is degraded

Engineering Contradiction:
Improvedecoupling effectivenessVSAvoidguiding precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

A decoupling device with a shaft and support members acts as an intermediary between the door and the link mechanism. The shaft can translate along its axis to provide decoupling while the support members maintain guidance precision during operation

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The decoupling device transitions from a static connection to a dynamic system where the shaft can translate and the support members can adjust their position, allowing the system to adapt between guided motion and decoupled states

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If a deformable parallelogram is used to guide the door, then guidance during docking and withdrawal is provided, but complete decoupling when the door is closed cannot be achieved

Engineering Contradiction:
Improveguidance during dockingVSAvoiddecoupling completeness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The connection system is segmented into distinct functional components: the link mechanism for guidance, the decoupling device with shaft for decoupling, and support members for maintaining position. This segmentation allows each component to perform its specific function without compromising the others

Inventive Principle:
Principle #1Segmentation

3Reliability

If elastomeric dampers are used for decoupling, then mechanical action transmission is reduced, but the decoupling effectiveness varies with temperature and pressure

Engineering Contradiction:
Improvemechanical action isolationVSAvoidenvironmental independence
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces elastomeric mechanical elements with a mechanical decoupling device using a shaft, support members, and ball joints. This substitution eliminates temperature and pressure sensitivity while maintaining effective decoupling of mechanical actions

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

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 solution achieves complete mechanical decoupling between the aircraft frame and door in the closed position, maintaining precise guidance and stiffness during opening and closing, independent of temperature and pressure variations, without degrading mechanical guidance or introducing elastomeric losses.

Implementation Method 1

a ball joint (66, 68) between the door (16) and each end of the shaft (42)

Methodology Applied
Scientific EffectSpherical contact interface: Ball

Implementation Method 2

an element (46) for elastic biasing of the shaft (42)

Methodology Applied
Scientific EffectElastic biasing: Spring

Data Source

PatentEP3219603B1Connecting mechanism between an aircraft door and a structure of the aircraft, related aircraft and method
Publication Date: 2020.04.08 DASSAULT AVIATION SA
  • EP3219603B1 patent drawingFigure 1
  • EP3219603B1 patent drawingFigure 2
  • EP3219603B1 patent drawingFigure 3~5

AI summary

The linking mechanism (18) comprises an arm (30) intended to be articulated on the structure (12), and a rotating linkage assembly (32) between the door and the arm (30). The rotating linkage assembly (32) can be disengaged from a configuration of the door linked to the arm (30) in an open position of the door, to a configuration of the door disengaged from the arm (30) in a closed position of the door.