Fuse Assembly With Friction-Fit Fusible Link Positioning

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Solution Overview

Problem

Existing fuses suffer from fusible links shifting during manufacturing, leading to deviations in switching behavior and inadequate solder connections, necessitating complex and costly visual inspections.

Innovation Solution

A friction-fit fixing device is used to securely position the fusible link within the insulating body, ensuring it remains centered and aligned, and allows for a stable electrical connection with outer contact caps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the fusible link is inserted into the insulating body without a fixing device, then the manufacturing process is simple, but the fusible link shifts during assembly leading to deviations in switching behavior

Engineering Contradiction:
Improvepositioning precision of fusible linkVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A fixing device is introduced as an intermediary component between the fusible link and the insulating body. This fixing device includes fixing elements that engage with the fusible link and anchor it in the correct position within the insulating body, preventing displacement during assembly while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The fixing device is pre-positioned within the insulating body before the fusible link is inserted. This preliminary action ensures that the fusible link is guided into its correct position and immediately secured, preventing any shifting or displacement that would occur without pre-established fixing mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If visual inspection is performed to detect fusible link displacement, then defective fuses can be identified, but the inspection process becomes complex and expensive

Engineering Contradiction:
Improvequality controlVSAvoidinspection process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fixing device is designed to be self-evident in its function, providing mechanical assurance that the fusible link remains properly positioned. The design inherently prevents displacement through its structural features, eliminating the need for complex post-assembly visual inspection processes to detect positioning errors.

Inventive Principle:
Principle #25Self-service

3Reliability

If the fusible link is allowed to move freely in the insulating body, then assembly is easy, but the solder connection becomes insufficient leading to unreliable electrical contact

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidassembly ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fixing device serves as a mediator that simultaneously achieves two objectives: it secures the fusible link in the correct position to ensure reliable solder connections with contact caps, and it is designed to be easily installed during the assembly process, maintaining ease of manufacture while improving connection reliability.

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

This solution reduces manufacturing costs by eliminating the need for complex optical inspections and ensures reliable electrical contact, preventing damage from defective fuses.

Implementation Method 1

a friction-fit fixing device for the fusible link during fuse assembly. This allows the fusible link to be held in a stable position within the insulating body

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The electrical contact between the fusible link and the outer contact caps is established by a solder connection. Furthermore, the solder connection also provides a metallurgical bond between the outer contact caps and the insulating body.

Methodology Applied
Scientific EffectSoldering: Soldering

Data Source

PatentEP4264651B1Fuse, and process for manufacturing a fuse
Publication Date: 2025.12.10 SIBA FUSES GMBH
  • EP4264651B1 patent drawingFigure 1
  • EP4264651B1 patent drawingFigure 2
  • EP4264651B1 patent drawingFigure 3~5

AI summary

The invention relates to a fuse (1), in particular an SMD fuse and/or an instrument fuse, comprising an insulator (2), a fusible conductor (3) arranged in the insulator (2), and outer contact caps (4) which are placed on the insulator (2) and are electrically connected to the fusible conductor (3). According to the invention, in order to be arranged in a stable position in the insulator (2), the fusible conductor (3) is at least frictionally engagingly attached by means of an attachment device (8).