Circuit Breaker Trip Unit Fixation Against Wire-Securing Forces

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Solution Overview

Problem

Circuit breakers experience accuracy and performance issues due to mechanical forces causing trip units to move within the frame when wires are secured, affecting the bimetal strip and short circuit trip units, leading to potential deflection and inaccurate operation.

Innovation Solution

The implementation of protrusions and openings in the frame or trip units to oppose movement of the trip units in the direction of securing forces, minimizing lateral and rotational displacement by conforming to each other, thereby stabilizing the trip units.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wires are secured to the trip unit terminal, then electrical connection is established, but mechanical forces cause trip unit movement and deflection

Engineering Contradiction:
Improvetrip unit stabilityVSAvoidtrip unit positioning accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary anti-action by positioning protrusions and openings in advance to counteract the mechanical forces that will be applied during wire securing. The protrusions are strategically located to oppose the direction of forces generated when wires are tightened to the terminal, preventing trip unit movement before the harmful displacement occurs.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The patent implements local quality by adding protrusions only in specific locations where mechanical forces are most likely to cause displacement. Rather than reinforcing the entire trip unit structure, protrusions are placed locally at critical points where wire securing forces are applied, providing targeted stabilization without increasing overall device complexity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If trip unit is firmly secured to prevent movement, then operational accuracy is maintained, but device complexity increases

Engineering Contradiction:
Improvetrip unit positioning accuracyVSAvoidframe structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements local quality by adding protrusions only in specific locations where mechanical forces are most likely to cause displacement. Rather than reinforcing the entire trip unit structure, protrusions are placed locally at critical points where wire securing forces are applied, providing targeted stabilization without increasing overall device complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies inversion by reversing the traditional approach of securing the trip unit to the frame. Instead of adding complex mounting mechanisms to the frame, the solution integrates protrusions directly into the trip unit itself, allowing the trip unit to actively engage with corresponding openings in the frame structure.

Inventive Principle:
Principle #13The other way round (Inversion)

3Stability of the object's composition

If protrusions and openings are added to oppose movement, then trip unit stability is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvetrip unit stabilityVSAvoidframe and trip unit fabrication
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent implements local quality by adding protrusions only in specific locations where mechanical forces are most likely to cause displacement. Rather than reinforcing the entire trip unit structure, protrusions are placed locally at critical points where wire securing forces are applied, providing targeted stabilization without increasing overall device complexity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3920205B1Trip fixation in a circuit breaker
Publication Date: 2025.07.02 ROCKWELL AUTOMATION SWITZERLAND
  • EP3920205B1 patent drawingFigure 1A
  • EP3920205B1 patent drawingFigure 1B
  • EP3920205B1 patent drawingFigure 1C

AI summary

A circuit breaker with improved trip unit fixation is disclosed. Another circuit breaker and a system also perform the functions of the circuit breaker. A circuit breaker includes a frame and a trip unit mounted in the frame. The trip unit includes a terminal for securing a wire to the trip unit. One of a wall of the frame and the trip unit include a protrusion and the wall of the frame or the trip unit without the protrusion includes an opening. The protrusion conforms to the opening and the protrusion and opening are positioned to oppose movement of the trip unit in a direction of a force resulting from securing the wire in the terminal.