Adjustable Stop for Circuit Breaker Calibration Spring

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Solution Overview

Problem

Existing electrical line protection devices of the circuit breaker type face inaccuracies in magnetic force thresholds due to manufacturing dispersions, leading to increased costs and complexity in achieving precise protection, especially in compact designs.

Innovation Solution

An adjustable stop mechanism allows quick modification of the calibration spring's position and prestress, enabling precise adjustment of the magnetic triggering threshold without disassembly, using a polygonal adjustable stop with marked positions for easy rotation and minimal angular deviation, maintaining compactness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manufacturing dispersions of components are reduced to obtain precise magnetic force threshold, then manufacturing precision is improved, but manufacturing cost increases significantly

Engineering Contradiction:
Improvemagnetic force threshold precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by allowing the spring attachment position to be varied along the shaft axis. Instead of improving manufacturing precision of fixed components, the system changes the operational parameter (attachment position) to compensate for manufacturing dispersions. The spring can be attached at different positions to adjust the magnetic force threshold, enabling cost-effective precision adjustment after assembly.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If spring replacement is performed after assembly to adjust force level, then manufacturing precision is improved, but handling time and cost increase

Engineering Contradiction:
Improvemagnetic threshold precisionVSAvoidadjustment handling time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the spring attachment position adjustable rather than fixed. The attachment mechanism allows the spring to be moved to different positions on the shaft and secured, transforming a static assembly into a dynamically adjustable one. This enables quick field adjustments without complete disassembly, reducing handling time and cost while achieving precise magnetic threshold calibration.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If multiple attachment positions for spring are provided to obtain different force levels, then adaptability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improveforce level adjustment capabilityVSAvoidattachment mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the shaft into multiple discrete attachment positions where the spring can be secured. Instead of a continuous adjustment mechanism, the shaft has segmented positions (e.g., notches or designated locations) that provide discrete force levels. This simplifies the attachment mechanism while maintaining adaptability, avoiding complex continuous adjustment systems.

Inventive Principle:
Principle #1Segmentation

4Manufacturing precision

If spring attachment position is made adjustable to correct magnetic triggering threshold, then manufacturing precision is improved, but device compactness may be compromised

Engineering Contradiction:
Improvemagnetic triggering threshold precisionVSAvoiddevice compactness
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent applies the nesting principle by integrating the spring attachment mechanism within the existing device structure. The spring attaches to the shaft at different positions along its length, utilizing the existing spatial envelope of the device. The adjustment mechanism is nested within the housing, allowing position variation without significantly increasing the overall device volume, thus maintaining compactness while enabling precision adjustment.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

This solution allows for precise calibration of the magnetic triggering threshold, compensating for manufacturing deviations without dismantling, reducing costs and maintaining device compactness, while providing stable and indexed adjustment positions.

Implementation Method 1

The current in the coil generates a magnetic attraction force on the mobile core depending on its intensity

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a movable core against a calibration spring having a calibrated force

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3300533B1Circuit breaker-type protective apparatus comprising a stop for adjusting the calibration spring
Publication Date: 2019.06.26 HAGER ELECTRO SAS
  • EP3300533B1 patent drawingFigure 1
  • EP3300533B1 patent drawingFigure 2~6

AI summary

Circuit breaker-type protective apparatus for power lines, comprising at least one electrical circuit designed to allow the current of a power line to pass, and a coil connected to this circuit, having a movable core (8), attracted by this coil, which is moved as from a magnetic force threshold, thereby compressing a calibration spring (14) having coils wound about a shaft (12) and an engagement part (16) connected thereto, to open a contact of the electrical circuit, the shaft (12) comprising an adjustment stop (30) on which the engagement part (16) of the spring (14) bears, and having several positions providing for variations in the positioning of this engagement part.