Switchgear Shutter Latch for Safe Maintenance Hold-Open

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Solution Overview

Problem

During maintenance, the need to manually manage shutter plates in switchgear housings can lead to risks if tools are forgotten, potentially damaging circuit breakers or disabling shutter plate movement, posing hazards to maintenance personnel.

Innovation Solution

A latch mechanism with a hook-shaped element guided along a spring-loaded J-shaped guide is introduced, allowing manual blocking of shutter plate movement during maintenance and automatic self-resetting upon reinsertion of the circuit breaker, ensuring safe and functional operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a tool is used to manually block the shutter plate during maintenance, then the shutter plate can be held open for maintenance access, but the tool may be forgotten and cause damage to circuit breakers or disable shutter plate movement

Engineering Contradiction:
Improvemanual shutter blockingVSAvoidoperational safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The latch mechanism is self-actuating through spring means that automatically return the hook-shaped element to the unlatched position when the circuit breaker is reinserted, eliminating the need for manual tool removal and preventing forgotten tools from causing damage

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The hook-shaped latch element acts as an intermediary between the maintenance personnel's manual blocking action and the shutter plate, providing a dedicated blocking mechanism that is automatically reset by the spring means when the circuit breaker is reinserted

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the shutter plate is manually blocked during maintenance, then maintenance personnel can safely access the opening, but the automatic shutter operation is disabled until the block is removed

Engineering Contradiction:
Improvemaintenance accessVSAvoidshutter operation
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The latch mechanism automatically resets itself through spring means when the circuit breaker is reinserted, restoring normal shutter operation without requiring maintenance personnel to manually remove the blocking tool or perform additional reset actions

Inventive Principle:
Principle #25Self-service

3Reliability

If a latch mechanism is added to enable automatic blocking, then operational safety is improved, but the device complexity increases

Engineering Contradiction:
Improveoperational safetyVSAvoidlatch mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The latch mechanism is implemented as a localized hook-shaped element with spring means positioned at a specific location on the shutter plate, adding minimal complexity only where needed for safety blocking rather than redesigning the entire shutter system

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of using a complex locking mechanism that requires active engagement, the invention uses a spring-loaded hook element that passively engages with the shutter plate and automatically disengages when needed, inverting the traditional active-locking approach

Inventive Principle:
Principle #13The other way round (Inversion)

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 latch mechanism ensures the shutter plates remain functional and safe, preventing damage to circuit breakers and maintaining operational safety by automatically resetting without manual intervention upon reinsertion, thus reducing risks to maintenance personnel.

Implementation Method 1

spring means for urging the hook-shaped element towards the unlatched position

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3747094B1Maintenance latch for switchgear shutter
Publication Date: 2024.06.12 EATON INTELLIGENT POWER LTD
  • EP3747094B1 patent drawingFigure 1
  • EP3747094B1 patent drawingFigure 2~3A
  • EP3747094B1 patent drawingFigure 3B~3C

AI summary

The invention relates to a switchgear housing for housing an object, such as a circuit breaker, the switchgear housing comprising: - a wall with an access opening for access to for example a high voltage connector; - at least one shutter plate movable parallel to the wall between a closed position, wherein the shutter plate covers the opening and an open position, wherein the shutter plate exposes the opening; - urging means for urging the at least one shutter plate towards the closed position; - an operating mechanism for operating the shutter plate from the closed position to the open position when an object such as a circuit breaker is moved into the housing; and - at least one latch movable in a direction perpendicular to the wall with the access opening and between a latched position and an unlatched position, wherein the path of the latch and the path of the shutter plate intersect, such that the latch, in the latched position, blocks movement of the shutter plate from the open position to the closed position.