Inline High-Current Fuse Holder With Reinforced Blade Contact

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Solution Overview

Problem

Existing inline fuse holders lack an effective mechanism for securely connecting high current fuses in electrical systems, particularly in applications like solar photovoltaic systems, where reliable overcurrent protection is crucial.

Innovation Solution

An inline fuse holder assembly that includes conductive end caps and contact elements with a base member, where the end caps are crimped to securely trap conductors and the contact elements are designed to increase contact force with the fuse blade, enhancing the electrical connection without additional fasteners or solder, and a cover that engages the contact elements to further secure the fuse in place.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional compression nut and two-piece holder body are used, then assembly is simple, but contact force and electrical connection reliability are insufficient for high current applications

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidholder structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the holder body and cover into a single integrated unitary structure, eliminating the need for separate compression nuts and multiple parts. This integration maintains structural simplicity while providing enhanced contact force and reliable electrical connection for high current applications through the monolithic design's inherent structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the electrical connection function into distinct contact elements within the unitary holder, allowing optimized contact geometry and force distribution. The segmented contact surfaces and internal structure enable high current carrying capacity while maintaining overall structural simplicity.

Inventive Principle:
Principle #1Segmentation

2Strength

If additional fasteners or solder are used to secure fuse, then connection strength increases, but device complexity and assembly steps increase

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The unitary holder structure provides self-service by incorporating integrated contact elements and securing mechanisms that automatically engage with the fuse blade upon insertion. The design eliminates the need for additional fasteners or soldering operations, as the holder's own structure provides both electrical connection and mechanical securing through its monolithic construction and internal geometry.

Inventive Principle:
Principle #25Self-service

3Reliability

If contact force between fuse blade and terminals is increased, then electrical connection reliability improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecontact force reliabilityVSAvoidcontact geometry precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes contact force by changing the geometric parameters of the contact elements within the unitary holder, such as contact surface area, angle, and positioning. These parameter optimizations enable high reliable electrical connection with standard manufacturing tolerances, avoiding the need for excessive precision while ensuring sufficient contact force for high current applications.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3577676B1In-line high current fuse holder assembly
Publication Date: 2024.06.05 LITTELFUSE INC
  • EP3577676B1 patent drawingFigure 1
  • EP3577676B1 patent drawingFigure 2~3
  • EP3577676B1 patent drawingFigure 4

AI summary

Provided herein are approaches for securing an electrical protection device (e.g., a fuse). In one approach, an apparatus includes a conductor and a terminal coupling the conductor to the fuse, wherein the terminal includes an end cap having a cavity for receiving and securing the conductor, and a set of contact elements extending from a base member. The base member may be coupled to the end cap, and a body of the fuse may be coupled to the base member. In some approaches, a fuse blade of the fuse is disposed between the set of contact elements. In some approaches, the apparatus further includes a cover adjacent the terminal, wherein the cover is configured to engage the contact elements to increase a contact force and electrical connection between the set of contact elements and the fuse blade.