Thermal Switch Movable Contact Height Adjustment

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Solution Overview

Problem

Existing thermal switches face variations in the shape and secured position of thermally responsive plates, leading to inconsistencies in contact pressure and deformation during temperature calibration, which can result in reduced strength and durability of the container and variations in the short-time trip duration.

Innovation Solution

A method and device for adjusting the height of the movable contact by deforming the metal support to ensure the movable contact is within a predetermined height range, allowing for consistent contact pressure and reduced deformation during temperature calibration, using a holding part, pressing device, position measuring device, and control device to achieve precise positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the thermally responsive plate is drawn into a dish shape, then the plate can be formed with a predetermined curvature for thermal response, but variations in the curved shape occur due to processing variations, leading to inconsistencies in contact position and pressure

Engineering Contradiction:
Improvecurved shape of thermally responsive plateVSAvoidconsistency of contact position
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by adjusting the height of the movable contact before the final assembly and calibration steps. The movable contact height is adjusted to a predetermined value within a specific range, which compensates for variations in the thermally responsive plate's curved shape. This preliminary adjustment ensures that even with processing variations, the contact position and pressure remain consistent during subsequent calibration operations.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the movable contact height is not adjusted, then the assembly process is simpler, but variations in contact pressure and deformation occur during temperature calibration, reducing product consistency

Engineering Contradiction:
Improveassembly process simplicityVSAvoidconsistency of temperature calibration
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the movable contact height parameter to fall within a predetermined range. This height adjustment compensates for variations in the thermally responsive plate's curved shape, ensuring consistent contact pressure and deformation characteristics during temperature calibration. By controlling this geometric parameter, the patent achieves reliable and consistent calibration results across different products.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the movable contact is positioned with high precision, then contact pressure consistency is improved, but the device complexity increases due to additional adjustment mechanisms

Engineering Contradiction:
Improvemovable contact position precisionVSAvoidadjustment device complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses a preliminary action approach where the movable contact height is adjusted within a predetermined range before final assembly. This preliminary adjustment simplifies the overall device structure compared to continuous adjustment mechanisms, while still achieving the necessary precision for consistent contact pressure and reliable temperature calibration.

Inventive Principle:
Principle #10Preliminary action

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 approach ensures stable contact pressure and reduced deformation, maintaining the strength and durability of the container while achieving consistent temperature calibration and reducing variations in the short-time trip duration across products.

Implementation Method 1

a thermally responsive plate such as a bimetal in a pressure-proof hermetic container... The thermally responsive plate reverses a direction of curvature thereof at a predetermined temperature

Methodology Applied
Scientific EffectBimetallic effect: Bi-Metallic Strip

Implementation Method 2

adjusting a position of the movable contact by deforming the metal support of the thermally responsive plate assembly from an initial shape

Methodology Applied
Scientific EffectMechanical deformation: Deformation

Data Source

PatentEP2947677B1Thermal switch, method for producing same, and device for adjusting height of mobile contact
Publication Date: 2020.01.15 UBUKATA IND CO LTD
  • EP2947677B1 patent drawingFigure 1
  • EP2947677B1 patent drawingFigure 2
  • EP2947677B1 patent drawingFigure 3

AI summary

A thermal switch includes a thermally responsive plate assembly (7) including a metal support (10) deforming from an initial shape before a header plate assembly (6) is secured to a housing assembly (5), with a result that a position of a movable contact (9) in the housing assembly (5) is adjusted so as to be within a predetermined height range relative to an open end of a housing (3). A contact pressure of switching contacts after the assembling is produced by the height adjustment, and subsequently, a neighborhood of a part of the housing (3) to which part the thermally responsive plate assembly (7) is secured is deformed, so that an operating temperature is calibratable.