Anti-Rebound Spring for Movable Contact in Medium Voltage Protection
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Solution Overview
Problem
Medium voltage electrical protection devices experience unpredictable rebound of movable contacts due to geometrical dispersions, energy variations, and material degradation at extreme temperatures, leading to inconsistent contact surfaces and potential loss of current passage.
Innovation Solution
An anti-rebound device with a retractable spring mounted on the movable contact that cooperates with a notch on the fixed contact, utilizing a horizontal strand to compress and index the movable contact, ensuring controlled damping and positioning during closure and opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hard stop is used to ensure the stopping of moving contacts, then the stopping position is guaranteed, but the rebound is not controlled and the contacts can deviate from their theoretical position leading to a loss of contact surface
Solution Approach 1:
The patent applies beforehand cushioning by introducing a spring mechanism that engages with a stop surface before the contact reaches its final position. The spring compresses during the closing operation and then expands to push the contact to its precise theoretical position, compensating for any deviations caused by the hard stop and ensuring consistent contact surface area.
Solution Approach 2:
The patent utilizes parameter changes by employing a spring with specific mechanical properties (elasticity, force constant) that transform the rigid stopping action into a controlled positioning process. The spring's elastic deformation allows it to absorb positioning errors and deliver the contact to the correct position with consistent force, thereby maintaining reliable contact.
2Reliability
If rubber stops or elastomers are used to dampen rebound, then some damping effect is achieved, but at high energy the rebound persists and the materials degrade at extreme temperatures and interact with SF6 gas
Solution Approach 1:
The patent replaces the elastomeric material with a spring mechanism that does not suffer from the same degradation issues. The spring, typically made of metal, is resistant to extreme temperatures and SF6 gas, providing a durable solution that maintains its damping and positioning functions throughout the device's operational life without material degradation.
Solution Approach 2:
The patent substitutes the elastomeric damping system with a mechanical spring-based system. This replacement eliminates the chemical degradation problems associated with rubber and elastomers while maintaining the necessary damping and positioning functions through purely mechanical means that are resistant to environmental factors.
3Device complexity
If no damping means are used, then the device structure remains simple, but the rebound causes random final positions and loss of contact surface
Solution Approach 1:
The patent applies segmentation by dividing the contact assembly into distinct functional components: the movable contact, the spring, and the stop surface. This segmentation allows each component to perform its specific function (motion, damping, positioning) independently, achieving precise contact positioning without requiring a complex integrated system.
Solution Approach 2:
The patent introduces an intermediary spring element between the movable contact and the stop surface. This intermediary component mediates the interaction between the contact and the stop, transforming the direct impact into a controlled compression and expansion cycle that ensures precise and repeatable contact positioning.
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 solution achieves a consistent and repetitive contact position, ensuring an optimal contact surface for current passage by effectively damping the rebound and indexing the movable contact relative to the fixed contact, maintaining performance across varying environments.
Implementation Method 1
a spring mounted on one, said first, of the two contacts, and capable of cooperating with the other, called the second, of these two contacts, at the end of the closing operation, so as to ensure the damping of the displacement of this first contact
Data Source
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AI summary
The present invention relates to an anti-bounce device for controlling the rebound of at least one movable contact (1,2,3) in an electrical apparatus, said movable contact being able to be moved between a closed position where said movable contact is in electrical contact with a fixed contact (4,5,6) of the apparatus so as to allow the passage of current between the two contacts, and a second position in which both contacts are separated, said device having damping means capable of limiting the rebound of the movable contact at the end of the closing operation of the movable contact. This device comprises a spring (13) mounted on one, called first contact, of the two contacts (1,2,3), and able to cooperate with each other (4,5,6), called second contact, of these two contacts at the end of the closing operation, so as to ensure the damping of the movement of the movable contact and indexing of the movable contact relative to the fixed contact.