Temperature Switch Spacer Assembly for Stable Low-Resistance Contact

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Solution Overview

Problem

Existing temperature-dependent switches suffer from increased rejection rates and contact resistance due to manufacturing tolerances and lack of a permanent galvanic connection between the spring element and the switch housing, leading to reduced service life and stability.

Innovation Solution

A temperature-dependent switch design that incorporates a spacer element to fix the spring element in position, providing a permanent galvanic connection and supporting the bimetallic element, thus reducing mechanical stress and improving manufacturing tolerance independence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spring element is permanently connected to the switch housing to ensure low contact resistance, then electrical connection reliability is improved, but mechanical stress on the spring element increases reducing service life

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidservice life of spring element
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent introduces a spacer element as an intermediary component between the spring element and the switch housing. The spacer element provides a permanent galvanic connection path for electrical current while mechanically decoupling the spring element from direct contact with the housing. This allows the spring element to maintain electrical connectivity without bearing mechanical stress from housing interactions, thus preserving both electrical reliability and mechanical service life.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If manufacturing tolerances are tightly controlled to ensure proper contact, then contact resistance is reduced, but production cost and rejection rate increase

Engineering Contradiction:
Improvecontact resistanceVSAvoidmanufacturing tolerance requirements
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The spacer element acts as a precision intermediary that establishes a defined galvanic connection path independent of housing-to-spring element tolerances. By providing a dedicated connection interface, the spacer element decouples the electrical contact quality from manufacturing tolerances of the main housing components, allowing for more relaxed tolerance specifications while maintaining low contact resistance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The spacer element is pre-configured with its electrical connection properties before final assembly. This preliminary preparation of the connection path ensures that proper galvanic contact is established in advance, eliminating the need for tight tolerance control during final assembly operations and reducing manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the spring element is allowed to move freely for optimal switching action, then switching performance is improved, but mechanical stability and position consistency deteriorate

Engineering Contradiction:
Improveswitching performanceVSAvoidmechanical stability of spring element
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The spacer element serves as a stable reference intermediary that provides consistent mechanical positioning for the spring element without constraining its switching motion. By mediating between the housing and spring element, it establishes a stable positional reference that maintains consistency across operating cycles while preserving the spring element's ability to perform optimal switching actions.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design enhances the switch's service life and stability by minimizing mechanical wear and contact resistance, while allowing for a simpler assembly process and reduced manufacturing rejections.

Implementation Method 1

The temperature-dependent switching behavior of the switching mechanism is primarily due to a temperature-dependent bimetallic element... consisting of two, three, or four interconnected components with different coefficients of thermal expansion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The spring element presses the movable contact against a stationary mating contact located on the inside of the switch casing

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4546389B1Temperature-dependent switch
Publication Date: 2026.04.01 HOFSAESS MARCEL P
  • EP4546389B1 patent drawingFigure 1
  • EP4546389B1 patent drawingFigure 2
  • EP4546389B1 patent drawingFigure 3

AI summary

Temperature-dependent switch (10) comprising: a switch housing (12) with a lower part (16) and a cover part (18) closing the lower part (16);a temperature-dependent switching mechanism (14) which is arranged in the switch housing (12) and has a movable contact part (30), a bimetallic element (26) and a spring element (24) cooperating with the movable contact part (30), wherein the switching mechanism (14) is configured to switch between a low-temperature position, in which it presses the movable contact part (30) against a contact surface (34) arranged inside the switch housing (12) and thereby establishes an electrical connection between a first electrical external terminal (56) of the switch (10) and a second electrical external terminal (58) of the switch (10), and a high-temperature position, in which it keeps the movable contact part (30) spaced away from the contact surface (34) and thereby interrupts the electrical connection between the first electrical external terminal (56) and the second electrical external terminal (58);and a spacer element (44) which is arranged inside the switch housing (12) between the lower part (16) and the cover part (18); wherein at least one section (42) of the spring element (24) is arranged between the spacer element (44) and the switch housing (12) and is fixed in position by an interaction of the spacer element (44) and the switch housing (12), and wherein at least one section (52) of the bimetallic element (26) is arranged between the spring element (24) and the spacer element (44) and is supported on the spacer element (44) in the high-temperature position of the switching mechanism (14).