Latch Handle Insert Structure for Open-Position Visibility

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Solution Overview

Problem

Latch handles on aircraft fan cowls are not sufficiently visible in the open position, increasing the risk of departure during flight if not properly secured.

Innovation Solution

A latch handle design with a removable insert notification feature that increases visibility when in the open position, allowing for easy replacement and featuring a snap-fit connection for convenience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a conventional latch handle design is used, then the structure is simple and manufacturing is easy, but the visibility in the open position is insufficient

Engineering Contradiction:
ImprovevisibilityVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The latch handle is divided into multiple components: a handle body, a separate notification feature with reflective material, and mounting structures. The notification feature can be independently attached to the handle body, allowing the visibility enhancement element to be segmented from the functional latch mechanism. This segmentation enables the reflective notification feature to be positioned optimally for visibility without complicating the core latching function.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The notification feature incorporates reflective material that changes its optical properties based on lighting conditions. When illuminated by external light sources, the reflective material reflects light back toward the observer, creating a visible notification. This passive optical change enhances visibility without requiring active illumination or complex electronic components, resolving the contradiction between visibility improvement and structural complexity.

Inventive Principle:
Principle #32Color changes

2Reliability

If the latch handle is made more visible with additional features, then safety improves, but manufacturing complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The reflective notification feature is pre-attached to the handle body during manufacturing, or can be easily attached in the field. This preliminary preparation ensures that the safety-enhancing visibility feature is already in place before the latch handle is installed on the aircraft, eliminating the need for complex post-assembly operations and simplifying the overall manufacturing process while maintaining safety improvements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The notification feature uses inexpensive reflective material that can be easily replaced if damaged or worn. Rather than using expensive, complex electronic visibility systems, the patent employs simple reflective elements that provide effective visibility enhancement at low cost and with minimal manufacturing complexity, while maintaining high reliability for safety purposes.

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

3Illumination intensity

If a permanent notification feature is integrated into the latch handle, then visibility is enhanced, but repair and replacement difficulty increases

Engineering Contradiction:
ImprovevisibilityVSAvoidreplacement difficulty
Core Design Contradiction:
Illumination intensityVSEase of repair

Solution Approach 1:

The notification feature is designed as a separate, detachable component from the handle body, allowing it to be independently removed and replaced. This segmentation enables maintenance personnel to replace only the notification feature without replacing the entire latch handle assembly, significantly reducing repair time and complexity while maintaining the visibility enhancement benefit.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The notification feature is designed to be replaceable rather than permanent, allowing damaged or worn notification elements to be discarded and replaced with new ones. The handle body and other functional components are retained and reused, separating the consumable notification element from the durable latching mechanism. This approach simplifies repair operations while preserving the visibility function.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP4464601B1Systems and methods for high visibility latch handle
Publication Date: 2026.04.08 ROHR INC
  • EP4464601B1 patent drawingFigure 1~2
  • EP4464601B1 patent drawingFigure 3
  • EP4464601B1 patent drawingFigure 4A~4B

AI summary

A latch handle arrangement (400) includes a latch handle body (410) and a removable insert (430). The latch handle body (410) comprises a first sidewall (412), a second sidewall (414), and a transverse wall (416) extending from the first sidewall (412) to the second sidewall (414). The latch handle body (410) further comprises one or more apertures (481, 482, 483, 484, 485, 486) disposed in the latch handle body (410). The removable insert (430) is configured to be coupled to the latch handle body (410). The removable insert (430) comprises an insert body (640) and one or more bosses (641, 642, 643, 644, 645, 646) protruding from the insert body (640) into the respective apertures (481, 482, 483, 484, 485, 486) disposed in the latch handle body (410), wherein the boss(es) (641, 642, 643, 644, 645, 646) are visible from an external surface of the latch handle body (410).