Segmented Key System for Switchgear Terminal Independence

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Solution Overview

Problem

Existing key systems for automatic terminals in fitting mechanisms face challenges in ensuring key independence, particularly in apparatus with reduced geometry, where the assembly of keys with the insulating base must precede the introduction of automatic terminals, and the use of flexible hinges restricts the assembly order.

Innovation Solution

A key system where multiple keys are connected to a common rotation shaft divided into sections, with each key rigidly linked to a distinct section, ensuring that direct actuation of one key rotates its section without inducing movement in adjacent sections, thus maintaining key independence and allowing assembly flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If keys are attached to a common element using flexible hinges, then key independence is ensured, but the assembly order is restricted requiring terminals to be mounted before installing the cover with keys

Engineering Contradiction:
Improvekey independenceVSAvoidassembly order flexibility
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The common element is divided into multiple independent sections, each rigidly connected to a specific key. The connection zones between sections are designed with selective mobility: they remain rigid when a key is directly actuated (ensuring key independence) but allow relative movement when terminals are inserted (enabling flexible assembly order). This segmentation allows the system to achieve both key independence and assembly flexibility simultaneously.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If keys are integrated with the rotation shaft, then assembly is simplified to a single step and keys cannot be lost, but the structure becomes more complex

Engineering Contradiction:
Improveassembly simplicityVSAvoidstructure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The keys are merged with the rotation shaft to form an integrated assembly. This combining eliminates the risk of losing separate keys and simplifies installation to a single step. The structural complexity is managed through the modular section design where each key-section unit can be independently analyzed, allowing the integrated system to be understood as a collection of simpler subsystems.

Inventive Principle:
Principle #5Merging (Combining)

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

The system ensures that each key can unlock its associated automatic terminal without unlocking others, facilitating a single-step installation of the key system in the fitting mechanism base and preventing loss of small keys, while maintaining assembly flexibility.

Implementation Method 1

the direct actuation by a user of any one of the keys causes the rotation around its longitudinal axis of the section to which this key is attached, to move the said key according to a determined angular deflection constituting the operational stroke of said key

Methodology Applied
Scientific EffectRotation:

Implementation Method 2

each connecting zone is arranged so that the rotation of a section, generated by the direct actuation of the attached key, keeps each adjacent section immobile or causes an incident rotation of each adjacent section around its longitudinal axis to move the adjacent key attached to this section following an incident angular displacement much less than the operational stroke of said adjacent key

Methodology Applied
Scientific EffectTorsion:

Data Source

PatentEP4191796A1Key system for disconnecting automatic terminals, apparatus mechanism comprising said system, and method for manufacturing said system
Publication Date: 2023.06.07 LEGRAND FRANCE SA
  • EP4191796A1 patent drawingFigure 1~2
  • EP4191796A1 patent drawingFigure 3~4
  • EP4191796A1 patent drawingFigure 5

AI summary

The invention relates to a key system (100) for disconnecting automatic terminals in a switchgear mechanism, comprising a plurality of keys (110, 120) attached to a common element, wherein the common element is a rotating shaft (130) divided into sections (131, 132) which are connected in pairs by connecting zones (133), each key being rigidly connected to a distinct section such that direct actuation by a user of any one of the keys causes rotation around its longitudinal axis (L1, L2) of said section to which that key is attached, to move said key through a determined angular displacement constituting the operational stroke of said key, and wherein each connecting zone is arranged so that the rotation of a section, generated by the direct actuation of the attached key,either holds each adjacent section stationary or causes an incident rotation of each adjacent section around its longitudinal axis to move the adjacent key attached to that adjacent section by an incident angular displacement significantly smaller than the operational stroke of said adjacent key. The invention also relates to a switchgear mechanism including this system and a method for manufacturing this system.