Aircraft Cowl Latch Lock Assembly for Vibration-Resistant Closure

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Solution Overview

Problem

Existing latch assemblies for aircraft cowls are prone to unintentional unlocking due to vibrations, posing a risk during events like fan blade out or extreme turbulence.

Innovation Solution

A latch assembly with a lock mechanism that includes a bolt, lever, spring, and retainer to secure the handle release device in place, preventing unintentional movement and ensuring the latch remains locked during vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional latch assembly is used for aircraft cowls, then the latch can be easily operated for opening and closing, but the latch is prone to unintentional unlocking due to vibrations during flight

Engineering Contradiction:
Improvehandle operationVSAvoidlatch locking stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The latch assembly is divided into functionally independent segments: a handle for operation, a lever for motion transmission, a spring for biasing, and a lock mechanism with bolt and retainer for securing. This segmentation allows each component to perform its specific function optimally while working together to solve the contradiction between ease of operation and locking stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lever acts as an intermediary between the handle and the lock mechanism, translating handle motion into locking action. The spring serves as an intermediary force, providing continuous biasing pressure on the lever to maintain engagement. These intermediary elements enable reliable locking while preserving easy operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the latch is designed to remain securely locked during vibrations, then reliability improves, but the device complexity increases due to additional lock components

Engineering Contradiction:
Improvelatch locking stabilityVSAvoidlock mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lock mechanism merges multiple functions into integrated components: the bolt serves both as a locking element and a motion transmission element; the retainer combines positioning and securing functions; the lever integrates motion transmission and engagement functions. This merging reduces the number of separate parts while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Each component of the lock mechanism is designed with multi-functionality: the bolt provides locking, positioning, and motion transmission; the spring provides biasing and returns the lever to its default position; the retainer provides both securing and alignment functions. This multi-functionality reduces overall device complexity while enhancing reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 lock mechanism effectively prevents the latch from inadvertently unlocking, maintaining the secure closure of aircraft cowls even under severe conditions, enhancing safety and reliability.

Implementation Method 1

A spring may be configured as or otherwise include a coil spring. The spring may be axially adjacent and contact the lever.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4368513B1Aircraft latch assembly with lock
Publication Date: 2026.03.04 ROHR INC
  • EP4368513B1 patent drawingFigure 1
  • EP4368513B1 patent drawingFigure 2
  • EP4368513B1 patent drawingFigure 3~4

AI summary

An aircraft assembly (20) includes a keeper (44), a latch (46) and a lock (50). The latch (46) includes a handle (51) and a hook structure (62) operatively coupled to the handle (51). The hook structure (62) is engaged with the keeper (44) when the handle (51) is in a closed position. The hook structure (62) is disengaged from the keeper (44) when the handle (51) is in an open position. The lock (50) includes a catch (78), a lever (84) and a spring (86). The lever (84) is configured to rotate about an axis (92) between a locked position and an unlocked position. The lever (84) is aligned with the catch (78) locking the handle (51) in the closed position when the lever (84) is in the locked position. The lever (84) is misaligned from the catch (78) unlocking the handle (51) from the closed position when the lever (84) is in the unlocked position. The spring (86) biases the lever (84) axially along the axis (92) in a direction towards the handle (51).