Generator Disconnect Latch for Vibration-Resistant Hold

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Solution Overview

Problem

Existing generator drive disconnect devices face challenges in maintaining the disconnected state under high vibration or severe operating conditions, as conventional spring-loaded latches may not provide sufficient force to prevent inadvertent reconnection.

Innovation Solution

A generator drive disconnect device with a latch mechanism that includes a support structure, a latch member, and a biasing mechanism, where the reaction force increases with the distance of the latch member from its retracted position, ensuring secure holding against vibrations and high acceleration loads without hindering the operation when in the retracted position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional spring-loaded latch is used, then the latch can provide some holding force, but the spring force is not sufficient to hold the latch in the latched state under high levels of vibration or severe operating conditions

Engineering Contradiction:
Improveholding force sufficiencyVSAvoidvibration impact
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The latch mechanism transitions from a static spring force to a dynamic reaction force that adapts to operating conditions. The reaction force increases with the distance of the latch member from the retracted position, providing higher holding force when needed (in extended position under vibration) and lower force when not needed (in retracted position), thereby resolving the contradiction between reliability under vibration and ease of operation.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a mechanical disconnect device with a large and powerful spring is used, then the assembly process is robust and reliable, but the axial force it can produce is typically limited

Engineering Contradiction:
Improveassembly robustnessVSAvoidaxial force production
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention changes the force parameter from a fixed spring force to a variable reaction force that depends on the latch member position. By making the reaction force magnitude increase with distance from the retracted position, the system achieves both the reliability of a robust mechanical assembly and the capability to produce sufficient axial force for disconnection under severe operating conditions.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If a basic spring loaded latch is used, then the spring rate can be selected as a compromise, but excessive frictional forces are applied to the disconnect device when the spring is compressed prior to actuation, which might otherwise hinder actuation

Engineering Contradiction:
Improvelatch actuation easeVSAvoidfrictional force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The dynamic reaction force mechanism ensures that when the latch member is in the retracted position (prior to actuation), the reaction force is at its minimum, thereby minimizing frictional forces and facilitating easy actuation. When the latch member moves to the extended position, the reaction force increases to provide secure holding, thus resolving the contradiction between ease of operation and holding force.

Inventive Principle:
Principle #15Dynamics

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 effectively maintains the disconnected state under severe conditions, preventing premature reconnection and ensuring the generator remains securely disconnected until the fault is resolved, while allowing easy reconnection when the situation is safe.

Implementation Method 1

a biasing mechanism configured to generate a biasing force to bias the latch member towards the extended position and to provide a reaction force to the latch member to resist movement of the latch member towards the retracted position

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3861224B1Aircraft engine generator disconnect device with latch
Publication Date: 2023.02.01 SAFRAN ELECTRICAL & POWER
  • EP3861224B1 patent drawingFigure 1
  • EP3861224B1 patent drawingFigure 2
  • EP3861224B1 patent drawingFigure 3

AI summary

The present invention relates to generator drive disconnect device (1) comprising a drive transfer means (100) having a connected configuration, and a disconnected configuration. The disconnect device (1) further comprises a disconnect mechanism (200), configured to move the drive transfer means from the connected configuration to the disconnected configuration, and a latch mechanism (300) configured to the hold the drive transfer means (100) in the disconnected configuration. The latch mechanism (300) includes a latch member (320), which is moveable between a retracted position and an extended position, and a biasing mechanism (330). The biasing mechanism (330) is configured to generate a biasing force to bias the latch member (320) towards the extended position and to apply a reaction force to the latch member (320) to resist movement of the latch member towards the retracted position, the reaction force having a magnitude which increases as a function of the distance of the latch member from the retracted position. Other aspects of the invention relate to an aircraft engine assembly and an aircraft comprising the generator drive disconnect device (1).