Insulating Shaft for Current Breaking Apparatus

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Solution Overview

Problem

Current low-voltage electrical current cut-off devices, such as branch circuit breakers, have a high manufacturing cost and complex assembly due to the large number of parts, which leads to insulation problems and assembly challenges.

Innovation Solution

A simplified design for the electrical current interrupting device featuring a single-piece insulating shaft with integrated baffle parts for enhanced insulation and reduced parts count, including a shaft with recesses and contact pressure springs for secure contact positioning and retention, facilitating assembly and reducing the risk of insulation issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single-piece insulating shaft is used, then device complexity and manufacturing cost are reduced, but insulation reliability may be compromised

Engineering Contradiction:
Improvenumber of partsVSAvoidelectrical insulation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges multiple separate components (metal axis, neutral coil, phase coils, bearing parts, crankshaft support, thermal release resetting parts) into a single insulating shaft made of thermoplastic material. This integration reduces the total part count from 5-9 parts to one piece, simplifying assembly and reducing manufacturing cost while maintaining insulation integrity through the inherent properties of the insulating material.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulating shaft performs multiple functions simultaneously: it serves as the structural axis for force transmission, provides electrical insulation between phases, supports bearing functions, holds the neutral and phase coils, and enables thermal release resetting. This multi-functionality eliminates the need for separate dedicated components for each function, resolving the contradiction between simplicity and reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Strength

If a metal axis is used for force transmission, then mechanical strength is improved, but electrical insulation problems occur

Engineering Contradiction:
Improveforce transmission capabilityVSAvoidelectrical insulation
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent replaces the traditional metal axis with an insulating shaft made of thermoplastic material. The insulating shaft maintains the necessary mechanical strength for force transmission through its structural design and material properties, while simultaneously providing electrical insulation between phases, thus eliminating the insulation problems associated with metal axes.

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

Solution Approach 2:

The use of thermoplastic material for the shaft creates a composite solution that combines mechanical strength requirements with electrical insulation properties. The material selection and structural design of the insulating shaft achieve both force transmission capability and electrical isolation, resolving the contradiction between mechanical strength and insulation reliability.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If multiple separate parts are used, then functional specialization is improved, but assembly complexity and cost increase

Engineering Contradiction:
Improvefunctional specializationVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functionally specialized parts into a single integrated insulating shaft. The design incorporates distinct zones and features within the unified structure that perform different functions (force transmission, insulation, bearing support, coil mounting, crankshaft support, thermal release resetting), thereby maintaining functional specialization while dramatically simplifying assembly to a single component installation.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2743947B1Support shaft of the movable contacts in an electric current breaking apparatus, and current breaking apparatus comprising same, in particular a coupling breaker
Publication Date: 2018.10.31 SCHNEIDER ELECTRIC IND SAS
  • EP2743947B1 patent drawingFigure 1~2a
  • EP2743947B1 patent drawingFigure 3~4
  • EP2743947B1 patent drawingFigure 5~6

AI summary

The shaft (8) has a mechanical connection unit (45) located in vicinity of an end of the shaft. Two zones are provided on two sides to retain mobile contacts (7) and a contact pressure spring. A set of parts is formed in certain shape to ensure rigidity of the shaft and transmission of a mechanical torque throughout the shaft. A reset unit is formed in corresponding shape of the shaft to allow resetting of various thermal triggers belonging to different phase subsets after an opening on defect. An independent claim is also included for an electric current breaking apparatus.