Movable Contact Spring Mechanism for Circuit Breaker Assembly

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Solution Overview

Problem

Existing line protection devices, such as circuit breakers and differential devices, face challenges in ensuring easy assembly and maintenance of articulation sub-assemblies without affecting the pivoting of movable contacts or the operation of torsion springs, while maintaining a stable electrical and mechanical connection.

Innovation Solution

The design features cylindrical housings with straight grooves for guiding the shaft and spiral torsion/compression springs with straight and curved ends, providing a stable bearing zone and facilitating easy insertion and positioning of the hinge sub-assembly, ensuring correct operation and positioning of the movable contact and its shaft within the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible conductive braid is used for connection, then the electrical connection is maintained during relative rotation, but the assembly and maintenance of the articulation sub-assembly becomes complex

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidarticulation sub-assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the flexible conductive braid from the articulation sub-assembly, extracting the electrical connection function to a fixed support that remains stationary relative to the housing. This simplifies the articulation sub-assembly while maintaining electrical connection through a different architectural approach.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a fixed support as an intermediary element that provides both mechanical support for pivoting and electrical connection. This mediator separates the rotational movement function from the electrical connection function, allowing the movable contact to pivot without requiring a flexible braid.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the movable contact is firmly fixed to the contact carrier, then the mechanical connection is strong, but the controlled rotational movement for contact force is lost

Engineering Contradiction:
Improvemechanical connection strengthVSAvoidcontrolled rotational movement
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent segments the connection into two independent parts: a fixed support that provides strong mechanical anchoring to the housing, and a movable contact that pivots independently on the fixed support. This segmentation allows the movable contact to rotate freely while maintaining a strong fixed connection point.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different connection qualities at different locations: the fixed support has a rigid, strong connection to the housing for mechanical stability, while the movable contact has a pivoting connection to the fixed support that allows controlled rotational movement for contact force adjustment.

Inventive Principle:
Principle #3Local quality

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 configuration allows for easy assembly and maintenance of the articulation sub-assembly, maintaining the stability and operation of the movable contact and its shaft, ensuring reliable electrical and mechanical connections and effective line protection.

Implementation Method 1

at least one spiral torsion spring substantially coaxial with said shaft and allowing the exercise of the contact force

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Implementation Method 2

two spiral torsion/compression springs arranged substantially coaxial with said shaft

Methodology Applied
Scientific EffectCompression spring: Spring

Data Source

PatentEP3134910B1Device with movable contact without conductive braid
Publication Date: 2018.02.28 HAGER ELECTRO SAS
  • EP3134910B1 patent drawingFigure 1~2
  • EP3134910B1 patent drawingFigure 3~4
  • EP3134910B1 patent drawingFigure 5~8

AI summary

The invention relates to a device with at least one movable contact for a protective apparatus, having a number of recesses equal to the number of movable contacts, a mounting which is stationary relative to the casing which enables the pivoting of said movable contacts and two torsion/compression spiral springs located on either side of the pivoting connection. The springs comprise a straight end provided such as to rest against an inner surface of the recess, and a curved end provided such as to catch on a tab projecting from the end of the movable contact arranged in the recess. The tab and the curved end of the spring are configured and oriented such that the latter exerts a dual force on the tab. Said tab additionally exerts a force substantially along the same line but in the opposite direction of the reaction force of the inner surface on the straight end resting on said surface.