Medium Voltage Switchgear Diaphragm Interlocking Mechanism

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Solution Overview

Problem

Existing medium-voltage switchgear electrical switch cabinets fail to keep the panel securely closed during malfunctions, such as electric arcs, which can lead to unintended opening under high pressure conditions, posing a risk to operators.

Innovation Solution

The switch cabinet design incorporates a front wall leg with a projection and a panel leg featuring a nose and incision, ensuring interlocking engagement in the locked position to prevent the panel from opening, even under fault conditions, through the use of a projection and indentation mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the panel is designed with simple front wall leg and panel leg structures, then the device complexity is reduced, but the reliability of keeping the panel securely closed during malfunctions deteriorates

Engineering Contradiction:
Improvestructure complexityVSAvoidpanel closure reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The front wall leg is divided into multiple segments including a first web, second web, and third web with distinct functions. The panel leg is similarly segmented with a first web, second web, and third web. This segmentation allows each segment to perform specific functions in the locking mechanism while maintaining overall structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third web of the panel leg is designed to be insertable into a recess of the second web of the front wall leg, creating a nested configuration. The projection on the third web fits into the recess of the second web, forming an interlocking nested structure that ensures reliable panel closure without complex additional components.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Manufacturing precision

If the front wall leg and panel leg use simple meandering edges without projections and recesses, then the manufacturing precision requirements are reduced, but the panel locking reliability under high pressure conditions deteriorates

Engineering Contradiction:
Improveedge alignment precisionVSAvoidpanel locking reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

While the overall edge configuration maintains a simple meandering pattern, specific local regions are enhanced with projections and corresponding recesses. The third web of the panel leg features a projection, and the second web of the front wall leg features a recess at the appropriate location. This local quality enhancement provides reliable mechanical interlocking without requiring high precision across the entire structure.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the panel leg web can move freely in the direction away from the opening, then the ease of operation for opening the panel is improved, but the reliability of preventing unintended opening during malfunctions deteriorates

Engineering Contradiction:
Improvepanel opening easeVSAvoidpanel closure stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The panel leg is designed with dynamic characteristics allowing free movement during normal operation for easy opening. However, the third web includes a projection that can engage with the recess in the front wall leg's second web, creating a dynamic locking mechanism. This allows the panel to be easily opened when needed while automatically locking to prevent unintended opening during malfunction conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2503656B1Electrical switching cabinet, in particular for a medium voltage switching assembly
Publication Date: 2015.02.11 SCHNEIDER ELECTRIC SACHSENWERK
  • EP2503656B1 patent drawingFigure 1a~1c
  • EP2503656B1 patent drawingFigure 2~4
  • EP2503656B1 patent drawingFigure 5a~6b

AI summary

The electrical switchgear cabinet has a housing in which an opening is formed. A diaphragm is engaged with an opening provided in a front wall (13) of housing. The front wall is provided with a front wall leg (19) having a bar (21) in which an incision (45) is formed. A projection provided in a bar (27) is latched with incision of bar (21) during locked position of diaphragm. USE : Electrical switchgear cabinet for medium-voltage switchgear. ADVANTAGE : The electrical switchgear cabinet can be designed easily in simple manner. Since projection provided in bar is latched with incision of another bar during locked position of diaphragm, the closing state of electrical switchgear cabinet is ensured even during unfavorable condition such as electric arc generation condition. DESCRIPTION OF DRAWINGS : The drawing shows the schematic view of the diaphragm in closed state. 11 : Side wall 13 : Front wall 19 : Front wall leg 21,27 : Bars 45 : Incision.