Aircraft Flap Locking Device with Photoluminescent Coating

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Solution Overview

Problem

Existing locking devices for aircraft flaps or doors, while designed to be aerodynamically flush and tool-free, often fail to provide adequate visual indication of their locked state, especially in low-light conditions, leading to safety risks due to potential mislocking and habituation to conventional conspicuous colors.

Innovation Solution

A locking device with internal surfaces coated in photoluminescent material that becomes visible in the open state, providing increased recognition under various lighting conditions, including dusk and darkness, and allowing for retrofitting without significant modification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If fluorescent paint is used on locking devices to improve visibility, then detectability is improved, but visibility in low-light conditions deteriorates because fluorescent colors require short-wavelength UV light to achieve their high-visibility effect

Engineering Contradiction:
Improvedetectability of locking deviceVSAvoidvisibility in low-light conditions
Core Design Contradiction:
Difficulty of detecting and measuringVSIllumination intensity

Solution Approach 1:

The patent changes the optical parameter of the locking device by using photoluminescent material that absorbs UV light and emits visible light at different wavelengths. This allows the locking device to be invisible under UV lighting (blends with aircraft skin) but highly visible in daylight or after UV charging, resolving the contradiction between detectability and low-light visibility.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs color-changing material that appears as a natural color (blending with aircraft skin) under certain lighting conditions but changes to a highly visible color when charged with UV light. This color transformation enables the locking device to provide visibility only when needed, solving the contradiction between being detectable and visible in low-light conditions.

Inventive Principle:
Principle #32Color changes

2Stability of the object's composition

If red or orange hues are used in aircraft exterior painting to maintain aesthetic consistency, then visual uniformity is improved, but detectability of locking devices deteriorates due to habituation to this color

Engineering Contradiction:
Improvevisual uniformity of aircraft exteriorVSAvoiddetectability of locking device
Core Design Contradiction:
Stability of the object's compositionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent uses photoluminescent material that changes color based on lighting conditions. In daylight or after UV charging, it emits a bright color that contrasts with the aircraft's red or orange exterior, making the locking device highly detectable. Under UV lighting, it blends with the aircraft skin, maintaining visual uniformity. This resolves the contradiction between visual uniformity and detectability.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent changes the optical parameters of the locking device by using material that absorbs UV light and emits visible light at different wavelengths. This allows the locking device to match the aircraft's exterior color under UV lighting but stand out in daylight or after UV charging, solving the contradiction between maintaining visual uniformity and improving detectability.

Inventive Principle:
Principle #35Parameter changes

3Difficulty of detecting and measuring

If additional devices are added to improve detectability of unlocked locking devices, then detectability is improved, but device complexity and installation effort increase

Engineering Contradiction:
Improvedetectability of locking deviceVSAvoidinstallation and maintenance effort
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent merges the visibility function directly into the locking device by coating it with photoluminescent material. This integration eliminates the need for separate detection devices, reducing overall system complexity while maintaining improved detectability. The locking device itself becomes the detection indicator through its optical properties.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The photoluminescent coating on the locking device provides self-service by automatically changing its visibility state based on lighting conditions. The material absorbs UV light and stores it, then emits visible light when needed, eliminating the need for external power sources, batteries, or complex electronic detection systems. This simplifies the overall system while improving detectability.

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

Enhances the visibility of the locking device's open state, ensuring safer aircraft operations by maintaining recognition even after maintenance lighting is off, and can be easily integrated into existing systems with minimal modification.

Implementation Method 1

at least a part of the surfaces of the locking device, which are located inside the surface in the locked state and are visible in the open state, are coated with photoluminescent material

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3728773B1Locking device for flaps on aircraft
Publication Date: 2021.11.03 LUFTHANSA TECHNIK AG
  • EP3728773B1 patent drawingFigure 1~2
  • EP3728773B1 patent drawingFigure 3~5

AI summary

The invention relates to a locking device (10) which can be embedded flush into a surface (1) and is intended for locking flaps (2), in particular for aircraft, comprising a plate (11) and a locking element (12) which can be actuated thereby, wherein, in the locked state of the locking device (10), the plate (11) is flush with the surface (1) and, in the open state, projects from the surface (1), wherein at least part of the faces (14) of the locking device (10), which are situated to the inside with respect to the surface (1) in the locked state and are visible only in the open state, is coated with photoluminescent material. The invention further relates to a method for retrofitting a locking device (10) to form a locking device (10) according to the invention.