Aircraft Door Emergency Actuator Using Retaining Wire

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Solution Overview

Problem

Existing aircraft emergency door opening devices are heavy, bulky, require maintenance, and rely on external energy sources or complex mechanical parts, which can lead to malfunctions and increased weight and bulk.

Innovation Solution

A purely mechanical emergency opening device using a tubular actuator with elastic compression means and a retaining wire, where the actuator is switched between retracted and deployed positions with minimal effort required, eliminating the need for external energy sources and complex mechanical parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If pneumatic actuators with reserve of working fluid are used, then the actuating means can provide sufficient force for emergency opening, but the weight and size of the device increase significantly

Engineering Contradiction:
Improveopening forceVSAvoidweight of actuating means
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The invention extracts and eliminates the pneumatic system and its working fluid reserve from the actuating means. Instead, it uses a spring mechanism that provides the necessary opening force without requiring any fluid supply system, thereby removing the source of excessive weight and size.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The spring mechanism is self-contained and self-pressurizing, requiring no external fluid supply or periodic monitoring. The spring automatically provides the necessary force for door opening and can be reset after use without requiring replacement of working fluid or external energy sources.

Inventive Principle:
Principle #25Self-service

2Reliability

If pneumatic actuators are used, then the actuating means can operate reliably, but periodic monitoring and replacement of working fluid reserve is required

Engineering Contradiction:
Improveoperational reliabilityVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring mechanism requires no periodic monitoring or maintenance. It is a passive mechanical system that remains ready for use without requiring inspection of fluid levels, pressure checks, or replacement of working fluid, thereby eliminating maintenance complexity while maintaining reliability.

Inventive Principle:
Principle #25Self-service

3Weight of moving object

If pyrotechnic cylinders are used, then the size and weight of actuating means are reduced, but periodic inspection and replacement is required even when not in use

Engineering Contradiction:
Improveweight of actuating meansVSAvoidinspection and replacement requirements
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The spring mechanism can be reset and reused indefinitely without replacement. After activation, the spring simply needs to be re-compressed into its stored energy state, allowing the same physical component to serve repeatedly without inspection or replacement, unlike single-use pyrotechnic devices.

Inventive Principle:
Principle #25Self-service

4Ease of operation

If electromagnet activation means are used, then the retaining member can be released with minimal effort, but external electrical energy source and control wiring are required

Engineering Contradiction:
Improveactivation effortVSAvoidelectrical systems required
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates all electrical systems including electromagnets, control wiring, and power sources from the actuating means. It replaces these with a purely mechanical trigger system that releases the spring's stored energy through simple mechanical linkage, thereby removing electrical complexity while maintaining ease of operation.

Inventive Principle:
Principle #2Taking out (Extraction)

5Force

If a mechanical retaining device with sufficient retaining force is created, then the opening force is sufficient, but the lever arm required becomes too large for compactness

Engineering Contradiction:
Improveretaining forceVSAvoiddevice compactness
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The actuating member is designed as a telescopic or nested structure that allows a long lever arm to be compactly stored within a small volume during normal conditions. When activated, the full length of the lever arm is deployed to provide the necessary mechanical advantage for door opening, thereby achieving both compactness and sufficient force.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 device is lightweight, compact, requires minimal maintenance, and ensures reliable operation with significant opening force without the need for external power or fluid, enhancing safety and reducing complexity.

Implementation Method 1

elastic compression means adapted to bias the tubular actuating member from its retracted position to its deployed position

Methodology Applied
Scientific EffectElastic compression: Spring

Data Source

PatentEP3996987B1Emergency opening device of an aircraft door with retaining wire
Publication Date: 2024.03.20 LATECOERE
  • EP3996987B1 patent drawingFigure 1
  • EP3996987B1 patent drawingFigure 2
  • EP3996987B1 patent drawingFigure 3

AI summary

The invention relates to an emergency opening device of an aircraft door, comprising: - a tubular actuating member (2); - resilient compression means (11); - a member for retaining the tubular actuating member (2), comprising a retaining wire (12) which, when the tubular actuating member (2) is in the retracted position, is held taut between a first attachment (14, 17) and a second attachment (16, 18); - release means which comprise a member (22) for transversely cutting the retaining wire (12).