Circuit Breaker Cradle Interlock Miniaturization

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Solution Overview

Problem

Conventional circuit breakers have a bulky design due to the mounting of the interlock device in the body, and the cradle drawing-in/out device allows the handle to be inserted even when the circuit breaker is on, compromising user safety and protection of power system components.

Innovation Solution

A circuit breaker design where the interlock device is mounted in a cradle, allowing the handle to be inserted only when the circuit breaker is off, and incorporating a cradle drawing-in/out device with a door member to prevent insertion when the circuit is on, ensuring user safety and protecting power system components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the interlock device is mounted in the body, then the circuit breaker can prevent connection during drawing-in/out operation, but the body size becomes bulky

Engineering Contradiction:
Improvesafety protectionVSAvoidbody size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The interlock device is separated from the body and mounted in the cradle instead, dividing the system into independent functional modules. This segmentation allows the body to be miniaturized while the cradle houses the interlock mechanism, resolving the contradiction between safety functionality and compact body size.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The interlock device is relocated from the body (one dimension) to the cradle (another dimension/space), changing the spatial arrangement. This dimensional relocation allows the body to be smaller while maintaining the safety function in the cradle assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the cradle drawing-in/out device allows free insertion, then the operation is convenient, but user safety and protection of power system components are compromised

Engineering Contradiction:
Improveinsertion convenienceVSAvoidaccidental connection risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The interlock device performs a preliminary check of the circuit breaker state (whether it is in the ON or OFF position) before allowing insertion. The drawing-in/out handle can only be inserted when the circuit breaker is in the OFF state, as the interlock mechanism prevents insertion in the ON state, thus preventing accidental connections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The interlock device acts as an intermediary between the drawing-in/out device and the circuit breaker body. It mediates the insertion operation by allowing it only under safe conditions (circuit breaker in OFF state), thereby protecting both users and power system components without completely preventing operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the interlock device is mounted in the cradle, then the body is miniaturized, but the cradle structure becomes more complex

Engineering Contradiction:
Improvebody sizeVSAvoidcradle structure
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The interlock device is integrated with the cradle structure, merging two components into one assembly. This combination allows the cradle to serve dual functions: supporting the circuit breaker and housing the interlock mechanism, thereby miniaturizing the body while managing the complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP1968090B1Circuit breaker
Publication Date: 2015.05.13 LG INDUSTRIAL SYSTEMS CO LTD
  • EP1968090B1 patent drawingFigure 1
  • EP1968090B1 patent drawingFigure 2
  • EP1968090B1 patent drawingFigure 3

AI summary

A circuit breaker is provided capable of miniaturizing a body by mounting an interlock device in a cradle, and capable of ensuring a user safety and protecting a line and an instrument on a power system by including a cradle drawing-in/out device capable of inserting a drawing-in/out handle of the circuit breaker in a shaft only when the circuit breaker is switched off.