Rotatable Knife Electrical Switch with Arc Contacts
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Solution Overview
Problem
Existing electrical switches require separate linkages to achieve overlapping of neutral contacts during switching, which complicates the design and increases operational torque, whereas the proposed solution integrates a rotatable knife contact with a spring structure and arc-shaped contact areas to facilitate a 'make-before-break' function without additional parts, reducing operation torque and allowing adjustable overlapping duration.
Innovation Solution
The electrical switch features a rotatable knife contact with a pair of blades connected by a spring structure, making contact with arc-shaped areas of the fixed contacts, enabling a zero switching position where both ends of the blades connect the first and second fixed contacts to the third, allowing for seamless transition between switching positions without extra components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate linkages are used to achieve overlapping of neutral contacts during switching, then the make-before-break function is realized, but the device complexity increases and operational torque increases
Solution Approach 1:
The patent merges the neutral contact overlapping function into the main switching mechanism by using a rotatable knife contact with arc-shaped contact areas. The arc-shaped design allows the knife contact to naturally overlap with both fixed contacts during rotation, eliminating the need for separate linkages while maintaining the make-before-break function.
Solution Approach 2:
The rotatable knife contact with arc-shaped contact areas serves multiple functions simultaneously: it provides the switching action, creates the overlapping period, and enables the make-before-break function. This multi-functional design replaces what would otherwise require separate dedicated components.
2Reliability
If separate linkages are used to achieve overlapping of neutral contacts, then the make-before-break function is realized, but the operation torque increases
Solution Approach 1:
By combining the overlapping function into the main switching mechanism through arc-shaped contact areas, the patent eliminates additional mechanical components that would increase torque requirements. The single rotational motion of the knife contact accomplishes both switching and overlapping without requiring separate actuation forces.
3Duration of action of moving object
If the contact areas are made thicker and longer to increase overlapping duration, then the adjustable overlapping duration is achieved, but the contact force increases
Solution Approach 1:
The patent allows adjustment of overlapping duration by modifying the geometric parameters (thickness and length) of the arc-shaped contact areas. This provides controllable adjustment of the overlapping period while managing the associated increase in contact force through proper dimensional design.
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
This design simplifies the overlapping of neutral contacts, reduces operation torque, and allows for adjustable overlapping duration by modifying the thickness and length of the contact areas, enhancing the switch's operational efficiency and reliability.
Implementation Method 1
the rotatable knife contact comprising at least one longitudinal pair of blades flexibly connected to each other with a spring structure
Data Source
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AI summary
The electrical switch comprises three fixed contacts (100, 200, 300) and a rotatable knife contact (400) being connected with a permanent electrical connection to a third one of the fixed contacts and comprising at least one pair of longitudinal blades. The rotatable knife contact connects in a first switching position only a first one and a third one of the fixed contacts electrically together, and in a second switching position only a second one and a third one of the fixed contacts. The rotatable knife contact connects further in a zero switching position the first, the second and the third fixed contact electrically together.