Circuit Breaker Position Indicator Gear Mechanism

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Solution Overview

Problem

Existing electrical switching apparatus, such as circuit breakers, face challenges in providing a constant and uninterrupted visual indication of the circuit breaker's position during the levering process into a cassette, due to intermittent mechanical drive mechanisms using partial gear teeth, cams, and slots.

Innovation Solution

A position indicator assembly that includes a drive shaft, indicator gears, and an indication rack, which cooperate to provide a visual indication of the circuit breaker's position relative to the cassette, utilizing a gear reduction mechanism to ensure accurate and continuous position feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If partial gear teeth, cams, and slots are used to drive the position indicator, then the device complexity is reduced, but the indication becomes intermittent and unreliable

Engineering Contradiction:
Improveposition indication continuityVSAvoidmechanical drive mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the continuity of useful action principle by replacing intermittent cam and slot mechanisms with a continuous gear-driven system. The drive gear engages with drive teeth on the drive shaft throughout the entire movement range, ensuring uninterrupted mechanical coupling and continuous position indication without dead zones or loss of control.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent substitutes the complex cam and slot mechanical system with a simpler gear-based mechanical system. This replacement maintains reliable mechanical coupling while reducing the complexity of the drive mechanism, eliminating the need for precision-cam profiles and slot geometries in favor of standard gear teeth engagement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a gear reduction mechanism is implemented, then the position indication precision is improved, but the device complexity increases

Engineering Contradiction:
Improveposition indication accuracyVSAvoidindicator mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediate gear reduction mechanism that acts as a mediator between the drive shaft and the position indicator. This intermediate stage amplifies the rotational movement of the drive shaft, providing enhanced position indication precision while isolating the complexity of the reduction mechanism from both the drive system and the indicator display.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the indicator mechanism into distinct functional components: the drive gear, the drive shaft with drive teeth, the position indicator, and the gear reduction mechanism. This segmentation allows each component to be optimized independently and simplifies manufacturing and assembly while maintaining overall system precision.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2387054B1Electrical switching apparatus, and levering assembly and position indicator assembly therefor
Publication Date: 2014.04.16 EATON CORP
  • EP2387054B1 patent drawingFigure 1
  • EP2387054B1 patent drawingFigure 2
  • EP2387054B1 patent drawingFigure 3~4

AI summary

A position indicator assembly is provided for a levering assembly of an electrical switching apparatus, such as a circuit breaker. The levering assembly includes a drive shaft and a racking member movably coupled to the circuit breaker housing. The drive shaft cooperates with the racking member to facilitate racking the circuit breaker into and out of a cassette. The position indicator assembly includes a number of indicator gears cooperating with the drive shaft, an indication rack cooperating with the indicator gears, and an indicator cooperating with the indication rack to provide a visual indication indicative of the position of the circuit breaker with respect to the cassette. When the circuit breaker is moved with respect to the cassette, the drive shaft pivots. In response, the indicator gears move, thereby moving the indication rack and the indicator in order to provide the visual indication.