Single-Bolt Fuse Assembly With an Electrically Isolated Bolt

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Single bolt fuses face issues with specially treated bolts becoming separated and being replaced with standard, uninsulated bolts, leading to improper functioning, and are limited in application due to their design for connection between a power terminal and either a battery terminal or bus bar.

Innovation Solution

A single bolt fuse assembly featuring an insulated steel bolt and metal terminal, where the bolt is mechanically attached to the terminal to prevent separation and ensure proper operation, allowing connection to any electrical device with a threaded hole, thus ensuring the fuse operates as intended across various applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the specially treated insulated bolt is separated from the fuse for installation, then the fuse can be attached to the circuit or device, but the bolt may become separated and lost, leading to replacement with standard uninsulated bolts that disrupt current path

Engineering Contradiction:
ImproveInstallation convenienceVSAvoidFuse operation reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent merges the fuse body and the insulated bolt into a single integrated unit where the bolt is permanently attached to the fuse. This integration ensures the bolt cannot be separated or lost during installation, eliminating the risk of being replaced with uninsulated bolts that would disrupt the current path and compromise fuse reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a metal terminal as an intermediary component between the insulated bolt and the circuit connection. The terminal provides a secure mounting interface that accepts the bolt while maintaining electrical isolation, ensuring proper current flow through the fuse element without direct contact between the bolt and conductive surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the single bolt fuse is designed for connection between power terminal and battery terminal or bus bar, then the connection is secure, but the application scope is limited

Engineering Contradiction:
ImproveConnection securityVSAvoidApplication scope
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent designs the fuse assembly with universal mounting capabilities by providing a metal terminal with a receptacle that can accommodate various bolt configurations and connection types. This universal design allows the fuse to be securely installed in diverse applications beyond traditional battery terminal connections, including general circuit protection, device mounting, and custom electrical assemblies.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4044209B1A single bolt fuse assembly with an electrically isolated bolt
Publication Date: 2024.04.24 LITTELFUSE INC
  • EP4044209B1 patent drawingFigure 1
  • EP4044209B1 patent drawingFigure 2A~2B
  • EP4044209B1 patent drawingFigure 3A~3C

AI summary

A single bolt fuse assembly and method to connect a single bolt fuse to a circuit or device are disclosed. The single bolt fuse assembly enables the single bolt fuse to be used on any electrical device having a hole suitable for receiving a threaded shaft and connectable to a circuit or device that electrically connects to a female battery or power cable. The apparatus includes a separate high-conductive metal terminal that mates with the stud that mechanically attaches the fuse between the electrical devices. The stud is insulated to avoid becoming part of the electrical circuit and to ensure proper operation of the fuse. By mechanically attaching the stud to the metal terminal, the stud is unlikely to get separated from the fuse.