Magnetic Switch Return Spring With Low Activation Counterforce

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Solution Overview

Problem

Existing switching devices, particularly power contactors, require significant energy to activate and overcome the counterforce of linear return springs, and additional components are needed for improved switching performance, such as in dual-spring mechanisms, which can complicate design and increase complexity.

Innovation Solution

A switching device with a movable contact and fixed contacts, utilizing a magnetic armature with a non-linear spring having distinct spring regions with different spring constants, allowing for efficient energy storage and release, reducing the initial counterforce requirement and simplifying the mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If linear return springs are used in switching devices, then the restoring force for contact separation is maintained, but the activation energy required is significantly increased

Engineering Contradiction:
Improverestoring forceVSAvoidactivation energy
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by transitioning from a linear spring with constant spring constant to a non-linear spring whose spring constant varies with compression distance. The non-linear spring has a first region with lower spring constant for initial compression and a second region with higher spring constant for final compression, optimizing the balance between restoring force and activation energy.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If dual-spring mechanisms are used to reduce initial counterforce, then the activation energy is reduced, but the device complexity increases due to additional components

Engineering Contradiction:
Improveactivation energyVSAvoidnumber of components
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the functions of two separate springs into a single non-linear spring structure. The non-linear spring integrates both the soft initial compression region and the hard final compression region within one continuous component, eliminating the need for separate springs, separators, and stops required in dual-spring mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The non-linear spring is segmented into different regions along its compression path: a first region with lower spring constant for initial compression and a second region with higher spring constant for final compression. This segmentation allows the spring to provide different mechanical characteristics at different stages of compression without requiring multiple separate components.

Inventive Principle:
Principle #1Segmentation

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

The non-linear spring design reduces the energy needed for activation and enhances switching reliability by minimizing the initial counterforce, while maintaining high restoring force for rapid contact separation, thus improving the switching process efficiency and reducing component complexity.

Implementation Method 1

a spring (10) which is designed to store energy during the transition from the first switching state to the second switching state, by means of which the movable contact (4) can be returned from the second switching state to the first switching state

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The movable contact is movable by means of a magnetic armature

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3791086B1Switch device
Publication Date: 2025.06.25 TDK ELECTRONICS AG
  • EP3791086B1 patent drawingFigure 1A
  • EP3791086B1 patent drawingFigure 1B
  • EP3791086B1 patent drawingFigure 2

AI summary

A switch device (100) is provided , comprising at least one fixed contact (2, 3) and a movable contact (4), wherein the movable contact (4) can be moved by a magnetic armature (5) from a first to a second switching state, the magnetic armature (5) comprises a spring (10) designed to return the movable contact (4) from the second switching state to the first switching state, and the spring (10) comprises a first spring region (10-1) with a first spring constant and a second spring region (10-2) with a second spring constant greater than the first spring constant.