Aircraft Door Safety Lock Using Electroactive Polymer Actuator

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Solution Overview

Problem

Aircraft doors require a safety locking mechanism that can ensure the door remains closed during safety conditions while allowing emergency opening without being obstructed by safety locks, and existing solutions are inefficient in terms of energy consumption and mechanical complexity.

Innovation Solution

An aircraft door system utilizing a security locking bolt with a movable locking element linked by an electroactive polymer (EAP) link, which transitions between locking and unlocking positions based on aircraft speed, powered by a control unit that energizes the EAP when the aircraft exceeds a predetermined speed threshold, ensuring safe and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional mechanical locking mechanisms are used, then the door can be locked securely, but the energy consumption increases and mechanical complexity rises

Engineering Contradiction:
Improvelocking reliabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces traditional mechanical locking mechanisms with an electroactive polymer (EAP)-based actuating system. The EAP material directly converts electrical energy to mechanical motion, eliminating the need for complex mechanical linkages, gears, and springs while maintaining secure locking functionality. This substitution reduces both energy consumption and mechanical complexity.

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

Solution Approach 2:

The patent utilizes the unique property of electroactive polymers to change their physical state (length, shape, or stiffness) in response to electrical field changes. By applying voltage, the EAP actuator changes from a relaxed state to an actuated state, providing controlled locking and unlocking motions with minimal energy input compared to traditional mechanical systems.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional mechanical locking mechanisms are used, then the door can be locked securely, but the device complexity increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidmechanical complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical locking mechanisms with an electroactive polymer (EAP)-based actuating system. The EAP material directly converts electrical energy to mechanical motion, eliminating the need for complex mechanical linkages, gears, and springs while maintaining secure locking functionality. This substitution reduces both energy consumption and mechanical complexity.

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

Solution Approach 2:

The patent extracts and removes unnecessary intermediate mechanical components from the locking system. By using EAP actuators that directly produce the required motion, the design eliminates redundant mechanical elements such as levers, linkages, and transmission mechanisms, thereby simplifying the overall device structure.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If conventional locking mechanisms are used, then the door remains locked during safety conditions, but the risk of blockage and overheating increases

Engineering Contradiction:
Improvesafety locking functionVSAvoidblockage and overheating risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces conventional mechanical locking mechanisms with an electroactive polymer-based system that uses electrostatic actuation instead of mechanical contact and friction. This substitution eliminates the risk of blockage and overheating associated with traditional mechanical components while maintaining reliable safety locking functionality.

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

Solution Approach 2:

The patent converts the potential harm of mechanical friction and contact (which cause overheating and blockage) into a beneficial electrostatic actuation system. The EAP materials operate without mechanical contact, transforming the problem of mechanical wear and heat generation into an advantage of frictionless, overheat-free operation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 provides a reliable, energy-efficient, and lightweight safety lock that reduces the risk of blockage and overheating, compatible with extreme temperatures, and allows for easy integration into aircraft door mechanisms, ensuring safe operation while minimizing electrical consumption.

Implementation Method 1

a connecting rod comprising at least one section of electroactive polymer, this connecting rod having a first end connected to an element of the door and a second end connected to the second movable locking element

Methodology Applied
Scientific EffectElectroactive polymer: Electroactive Polymer

Data Source

PatentEP4077126B1Aircraft door with safety locking system featuring an electroactive polymer connecting rod
Publication Date: 2024.06.12 LATECOERE
  • EP4077126B1 patent drawingFigure 1~2
  • EP4077126B1 patent drawingFigure 3~4
  • EP4077126B1 patent drawingFigure 5~7

AI summary

The invention relates to an aircraft door (1) comprising: a safety latch (7) comprising a first locking member (8) and a complementary second locking member (9) which is movable; a link (11) comprising at least one section (13) of electroactive polymer suitable for occupying: a locked position in which the section (13) of electroactive polymer is receiving power and the second movable locking member (9) is engaged with the first locking member (8); and an unlocked position in which the section (13) of electroactive polymer is not receiving power and the second movable locking member (9) is kept away from the first locking member (8); a control unit (16) comprising an electrical power supply (26) to the section (13) of electroactive polymer.