Knife Switch Dielectric Shield Coupling to Limit Arc Initiation
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Solution Overview
Problem
Existing electric knife switches face inefficiencies and safety risks due to dielectric shields obstructing optimal contact and inadvertently becoming arc initiation sites during switching, compromising electrical connection efficiency and safety.
Innovation Solution
A movable dielectric shield is mechanically coupled to a contact lever, synchronizing its movement with the lever's rotation to timely cover and expose contact areas, ensuring dielectric protection and minimizing arc formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dielectric shield is used to protect surrounding components from electric arcs, then protection from electric arcs is improved, but the dielectric shield obstructs optimal contact between switching components and becomes a site where electric arcs initiate
Solution Approach 1:
The patent applies the dynamics principle by making the dielectric shield movable rather than stationary. The shield is coupled to the movable contact lever through a mechanical coupling mechanism, allowing it to dynamically adjust its position. During switching operations, the dielectric shield moves to cover the contact areas when contacts are open (providing protection) and moves away when contacts close (eliminating obstruction and arc initiation risks). This dynamic positioning resolves the contradiction between protection and reliability.
2Object-affected harmful factors
If a stationary dielectric shield is positioned to provide protection, then protection coverage is improved, but contact establishment is obstructed leading to dielectric issues
Solution Approach 1:
The patent transforms the stationary dielectric shield into a dynamic component that moves with the contact lever. The mechanical coupling ensures the shield's position changes synchronously with contact lever movement. When the contact lever opens, the shield moves into position to provide dielectric protection; when the contact lever closes, the shield moves away to allow optimal contact establishment. This dynamic behavior eliminates the obstruction problem while maintaining protection coverage.
3Object-affected harmful factors
If the dielectric shield remains in a fixed covering position, then continuous protection is improved, but the shield becomes a site where electric arcs initiate during switching
Solution Approach 1:
The patent implements periodic action by making the dielectric shield's coverage periodic rather than continuous. The shield covers the contact areas during the open state and moves away during the closing state, creating a periodic pattern of coverage that aligns with the switching cycle. This periodic positioning prevents the shield from being a continuous arc initiation site while still providing arc suppression during the critical open state when arcs are most likely to occur.
Solution Approach 2:
The dynamic coupling between the contact lever and dielectric shield ensures the shield is positioned optimally at different phases of the switching cycle. During contact closing, the shield moves away to prevent arc initiation on its surface. During contact opening, the shield moves into position to suppress arcs. This dynamic positioning strategy eliminates the problem of the shield becoming an arc initiation site while maintaining continuous protection capability.
Data Source
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AI summary
The present invention relates to an electric current switch (100, 200) comprising: a movable contact lever (102, 202) comprising a lever main contact area (141, 241); a fixed contact assembly (116, 216) comprising a fixed main contact (152, 252), the contact lever is configured to rotate about the pivot point between the closed position (P1) and an open position (P2), the electric current switch further comprising a movable dielectric shield (160, 260), wherein the movement of the movable dielectric shield is between a covering position (C1) wherein it covers the one of the fixed main contact of the fixed contact assembly or the main contact area of the contact lever, and a second position (C2) where the movable dielectric shield has moved away from the covering position, and the movement of the movable dielectric shield is mechanically coupled to the rotation of the contact lever.