Temperature Limiter Insulating Sleeve Folding

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Solution Overview

Problem

Existing temperature limiters, particularly thermal switches, face challenges in miniaturization due to increasing electrical assembly sizes, requiring a reduction in size without increasing costs or compromising insulation and current-carrying capacity.

Innovation Solution

The temperature limiter's electrically insulating sleeve is shortened by folding sections from the narrow sides, top, and bottom against the front, allowing for a compact design without altering the housing or switching mechanism, ensuring adequate insulation and avoiding sharp edges that could damage wires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the temperature limiter is miniaturized by shortening the electrically insulating sleeve, then the length is reduced by 10% to 15%, but the insulation strength and electrical creepage distance must be maintained

Engineering Contradiction:
Improvelength of temperature limiterVSAvoidinsulation strength
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent transitions from a conventional tapered closure to a folded flat closure, changing the dimensional approach to achieving compactness. By folding the sleeve material back on itself in multiple directions (front, sides, top, bottom), the insulation is redirected rather than compressed, maintaining electrical creepage distance while reducing overall length projection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The folded sections of the electrically insulating sleeve are nested within each other, with each fold containing the previous fold. This nested structure allows the insulation material to be compacted into a smaller space while maintaining the required insulation thickness and electrical creepage distance between conductive parts.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of moving object

If the sleeve is shortened through folding, then the length is reduced, but the manufacturing complexity increases due to multiple folding and welding operations

Engineering Contradiction:
Improvelength of temperature limiterVSAvoidmanufacturing process complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The folding process is segmented into distinct sequential steps: first folding from the front, then from the sides, and finally from the top and bottom. This segmentation allows each folding operation to be performed independently and controlled separately, making the complex process more manageable and suitable for automated manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sleeve is pre-formed with appropriate dimensions and material properties before the folding process begins. The material is selected and prepared in advance to accommodate the multiple folding operations and welding steps, ensuring that the final compact structure achieves the desired insulation properties without requiring complex real-time adjustments during manufacturing.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the sleeve is tapered in the conventional manner, then the manufacturing is simple, but sharp edges and pointed corners are created that could damage sensitive wires

Engineering Contradiction:
Improvesleeve manufacturing simplicityVSAvoidwire damage risk
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The folded flat closure creates rounded contours and eliminates sharp edges and pointed corners through the folding geometry itself. The multiple folds naturally distribute the material in a way that creates smooth transitions and rounded surfaces, protecting sensitive wires from mechanical damage during insertion and operation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The conventional tapering process that creates sharp edges is converted into a beneficial folded structure. By folding the material back on itself rather than simply tapering it, the potential harm of sharp edges is transformed into the benefit of rounded protective surfaces, while the material still achieves the necessary compression and closure function.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 allows for a 10% to 15% reduction in length without increasing costs or affecting the switching mechanism's properties, maintaining insulation strength and preventing damage to sensitive wires.

Implementation Method 1

An electrically insulating sleeve made of a shrinkable plastic film is provided on the housing. The cover is pushed onto the thermal switch housing and shrunk on.

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP1983539B1Temperature limiter and method for its manufacture
Publication Date: 2012.02.29 TMC SENSORTECHN
  • EP1983539B1 patent drawingFigure 1~4
  • EP1983539B1 patent drawingFigure 5~6

AI summary

The limiter i.e. thermo switch (1), has a front side (3) at which an upper side (4), a lower side (5) and two narrow sides are attached. A body (11) is designed as a metallic housing and enclosed by an electrically insulating casing (10), which is formed from a tube section that is folded at an end and closed in an adhesively joined manner, where the closed end of the tube section covers the front side. The casing is folded by the narrow sides with sections (10a), by the upper side and by the lower side with sections (10b) against the front side so that the casing is completely covered. An independent claim is also included for a method for manufacturing a casing closed at an end from a tube and attaching the casing on a temperature limiter e.g. thermo switch.