Intermittent Gear Switch Mechanism for Precise Contact Positioning
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Solution Overview
Problem
Existing two and three position switches for medium voltage or high voltage switchgear require increased overlap and precise positioning of moveable contacts to maintain contact during nominal and short circuit currents, leading to higher production costs and complexity.
Innovation Solution
The use of a gear wheel system comprising a first gear wheel and a second gear wheel, where the second gear wheel intermittently rotates the first gear wheel, allowing for precise control of the moveable contact's static positions without the need for extensive overlap, utilizing a starwheel mechanism with driver bolts for smooth and shock-free motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If direct driven contact system is used to move the switch to particular position, then the switch can be actuated simply, but the moveable contact requires increased overlap area with fixed contacts to maintain sufficient contact under load and during short circuit current
Solution Approach 1:
The patent employs an intermittent gear mechanism where the second gear wheel rotates intermittently to drive the first gear wheel, which in turn moves the moveable contact. This periodic action allows the contact to be precisely positioned and held stationary once in the correct position, eliminating the need for continuous overlap to maintain contact under load.
2Device complexity
If direct driven contact system is used, then the structure can be simpler, but the drive gear must very accurately position the moveable contact which leads to increased production requirements and costs
Solution Approach 1:
The patent introduces an intermediary intermittent gear mechanism between the drive gear and the moveable contact. This intermediary mechanism absorbs positioning tolerances and ensures that once the moveable contact reaches the correct position, further rotation of the drive gear does not displace it, thereby reducing manufacturing precision requirements while maintaining reliable contact positioning.
Data Source
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AI summary
The present invention relates a switch for a medium voltage or high voltage switchgear. The switch comprises: a first fixed contact; a second fixed contact; a moveable contact; a first gear wheel; and a second gear wheel. In an on state of the switch the moveable contact is in a position that connects the first fixed contact to the second fixed contact. In an off state of the switch the moveable contact is in a position where the first fixed contact is not connected to the second fixed contact. Rotation of the first gear wheel is configured to move the moveable contact. Rotation of the second gear wheel is configured to intermittently rotate the first gear wheel.