Universal Load Switch With Convex Contacts and Snap Blades
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Solution Overview
Problem
Existing electrical switches face issues with arcing and contact welding, particularly in high-power applications, leading to operational disruptions and the need for costly replacement or redundancy to maintain functionality.
Innovation Solution
A universal load switch with convex fixed and movable contacts, a contact blade assembly, and snap blades that forcibly move the contact blade assembly toward and away from terminal contacts, providing redundancy and forced contact breakage to address welding issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different switch constructions are provided for high power and low power applications, then reliability for specific power levels is improved, but device complexity and inventory requirements increase
Solution Approach 1:
The patent applies universality by designing a single switch construction that can handle both low power and high power applications. The switch uses universal contact blades and terminal contacts that can accommodate different power levels without requiring different switch models, thereby reducing inventory complexity while maintaining reliability across applications.
Solution Approach 2:
The patent employs parameter changes by allowing the same switch construction to operate across different power parameters. By designing contacts and terminals with sufficient margins and appropriate material properties, the switch can safely handle varying current and voltage levels without requiring construction changes for each power level.
2Speed
If switch contacts are opened and closed frequently and rapidly, then operational responsiveness is improved, but arcing and contact welding increase
Solution Approach 1:
The patent applies the skipping principle by designing the contact blade and terminal contact geometry to minimize the duration of the arcing event. The contacts are shaped and positioned to achieve rapid make and break, rushing through the arcing phase as quickly as possible to reduce the time during which harmful effects can occur.
Solution Approach 2:
The patent converts the harmful arcing effect into a beneficial one by using the arc to clean the contact surfaces. The high temperature of the arc vaporizes and removes oxide and contaminant layers from the contacts, actually improving contact cleanliness and reducing future contact resistance, while the contact geometry ensures the arc does not cause welding.
3Reliability
If contact blades are forced to move rapidly to break welds, then contact separation reliability is improved, but mechanical stress on switch components increases
Solution Approach 1:
The patent applies preliminary action by pre-positioning the contact blade and terminal contact with appropriate clearance and geometry before actuation. The contacts are designed with initial spacing and angular relationships that facilitate smooth separation without requiring excessive force, thereby achieving reliable weld breakage while minimizing mechanical stress on the switch components.
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 enables the universal load switch to maintain operation even with welded contacts by forcibly breaking welds and ensuring reliable contact through redundant points, adapting to both low and high power applications with enhanced reliability and adaptability.
Implementation Method 1
Snap blades forcibly move the contact blade assembly toward and away from both of the terminals
Implementation Method 2
convex fixed terminal contacts and convex movable contacts selectively connectable electrically to the terminal contacts
Data Source
AI summary
A universal load switch includes convex fixed terminal contacts and convex movable contacts selectively connectable electrically to the terminal contacts. Snap blades forcibly move the movable contacts toward and away from each of the terminal contacts.