Contact Device Spring Application Triangle

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Solution Overview

Problem

Existing contact devices with movable contacts struggle to maintain stable contact with fixed contacts due to vibrations caused by electromagnetic forces and external factors, particularly when three movable contacts are designed to contact at multiple regions, leading to unstable current flow.

Innovation Solution

A contact device is designed with a movable terminal that includes three movable contacts, where the pressing spring's point of application is located within a triangle formed by the internal tangents of these contacts, ensuring all contacts are securely pressed against the fixed contacts, and optionally includes a spring bearing portion to shorten distances between contacts and enhance stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If three movable contacts are provided on the movable contact plate to improve current conduction stability, then the current conduction capability is improved, but the contact stability deteriorates due to vibration and localized acting forces making it difficult to bring all three contacts into stable contact

Engineering Contradiction:
Improvecurrent conduction stabilityVSAvoidcontact stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the geometric parameter of the pressing spring's point of application from arbitrary positioning to a specific location within the triangle formed by internal tangents of the three movable contacts. This parameter change ensures that the pressing force is distributed optimally to all three contacts, resolving the instability issue while maintaining the three-contact configuration for improved conduction.

Inventive Principle:
Principle #35Parameter changes

2Force

If a pressing spring is used to bias the movable contact plate toward the fixed contact, then the contact force is improved, but the contact stability deteriorates due to vibration from electromagnetic forces and external sources

Engineering Contradiction:
Improvepressing forceVSAvoidcontact stability under vibration
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent optimizes the positional parameter of the pressing spring's point of application within the triangle formed by internal tangents of the three movable contacts. This geometric constraint ensures that the pressing force is distributed in a way that maintains contact stability even under vibrational conditions, as the triangular configuration provides mechanical stability against vibration from electromagnetic forces and external sources.

Inventive Principle:
Principle #35Parameter changes

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 ensures stable conduction by securely bringing all movable contacts into contact with fixed contacts, reducing noise and improving contact wear resistance, thereby maintaining reliable electrical connection.

Implementation Method 1

a pressing spring that presses the movable terminal to bring the movable contacts into contact with the fixed contacts

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a coil that generates an electromagnetic force when electric current is applied

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 3

a magnetic field is generated around the movable contact plate, and a magnetic attractive force is generated between the first yoke plate and the second yoke plate

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 4

a magnetic attractive force is generated between the first yoke plate and the second yoke plate. Since the magnetic attractive force cancels out the repulsive force generated at the contacted region between the contacts

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Data Source

PatentEP2690642B1Contact device
Publication Date: 2016.12.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2690642B1 patent drawingFigure 1
  • EP2690642B1 patent drawingFigure 2~4
  • EP2690642B1 patent drawingFigure 5

AI summary

Provided is a contact device in which all of three movable contacts can be securely brought into contact with fixed contacts. The contact device includes a fixed terminal 37 that has a fixed contact 35, a movable terminal 28 that moves toward and away from the fixed terminal 37 and has three movable contacts 31a, 31b, and 31c that are brought into contact with the fixed contact 35, and a pressing spring 33 that presses the movable terminal 28 and brings the movable contacts 31a, 31b, and 31c into contact with the fixed contacts 35 at a predetermined pressing force. The point of application of the pressing spring 33 is located in a triangle formed by internal tangents of the three movable contacts.