NH Fuse-Disconnector Locking Mechanism for Controlled Fuse Holder Removal

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Solution Overview

Problem

Existing NH-type fuse disconnectors require additional components for release mechanisms, leading to increased costs and assembly issues, and existing solutions are prone to incorrect assembly or omission.

Innovation Solution

An ergonomic locking mechanism is integrated into the fuse holder and base, utilizing guiding means and a locking member with a lever to prevent unintentional removal of the fuse holder, allowing voluntary disassembly through a translational and tiltable motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a release mechanism is added to prevent unintentional removal, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveprevention of unintentional removalVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is integrated into the base structure itself, combining the base and locking elements into a single unified component. This eliminates the need for separate release mechanisms while maintaining the prevention of unintentional removal, thus improving reliability without increasing device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base structure provides its own locking function through integrated guiding means and locking elements that automatically engage with the fuse holder. The system serves itself by incorporating the locking capability directly into the base, eliminating the need for additional external release mechanisms

Inventive Principle:
Principle #25Self-service

2Reliability

If additional locking components are added, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvelocking functionVSAvoidmold development cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking elements and guiding means are integrated into the base mold as a single manufacturing unit. By combining multiple functions into one molded part, the patent eliminates the need for separate molds for locking components, thereby reducing mold development costs while maintaining reliable locking functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The base structure serves multiple functions simultaneously: it provides structural support, electrical connection, and integrated locking through its guiding means. This multi-functionality reduces the need for separate dedicated locking components, simplifying manufacturing and reducing mold development expenses

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

3Reliability

If a separate locking component is used, then locking function is improved, but assembly complexity increases

Engineering Contradiction:
Improvelocking functionVSAvoidassembly steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking elements are built into the base structure during manufacturing, eliminating the need for separate assembly of locking components. This integration reduces assembly complexity while maintaining the locking function, as the base and locking elements are produced as a unified structure

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4310876B1Electrical switchgear of the nh fuse-disconnector type
Publication Date: 2026.03.04 HAGER ELECTRO SAS
  • EP4310876B1 patent drawingFigure 1
  • EP4310876B1 patent drawingFigure 2
  • EP4310876B1 patent drawingFigure 3

AI summary

The invention relates to an electrical switching device comprising a fuse holder (1), a locking member (5) comprising a handle (6) and a locking portion (7), a base (8) comprising a receiving area (9) and a bottom (19), characterized in that: - the locking portion (7) comprises first guiding means and the base (8) comprises second guiding means, - the locking portion (7) is mounted to move in translation relative to said base (8) by the first and second guiding means between the closed contact position and the open contact position (POFF) along a first direction (D1) perpendicular to the bottom (19),and - the first guiding means and/or the second guiding means comprise locking means arranged to stop the translational movement of the locking portion (7) relative to the base (8) via the first and second guiding means in the so-called open contact position (POFF) so as to prevent the removal of the fuse holder (1) from the base (8) in a locked position of the locking member (5).