Service Plug Lever Locking Mechanism for Power Circuit Breakers
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Solution Overview
Problem
Existing power supply circuit breaker devices require high operation force due to static friction between main terminals when rotating from an engaged to a disengaged state, complicating the breaking operation.
Innovation Solution
The device incorporates a lever with a lock part that regulates rotation at a middle position, and contact pieces that elastically displace to reduce contact pressure between main terminals, minimizing static friction and improving operability during disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lever is rotated from the engaged position to the disengaged position to break the power supply circuit, then the power supply circuit is successfully broken, but large operation force is required due to static friction force generated between the main terminals
Solution Approach 1:
The patent segments the rotation path of the lever into two distinct phases: a first rotation phase where the lever rotates from the engaged position to a predetermined position (signal terminals disconnect first), and a second rotation phase where the lever rotates from the predetermined position to the disengaged position (main terminals disconnect). This segmentation allows the main terminals to remain connected during the first phase, avoiding static friction when initial rotation force is applied, thereby reducing the overall operation force required.
Solution Approach 2:
The patent implements preliminary action by first disconnecting the signal terminals before disconnecting the main terminals. The lever is designed with an operation portion that rotates first to disconnect the signal circuit switch, and only after reaching the predetermined position does the main circuit switch disconnect. This preliminary disconnection of the signal circuit eliminates the harmful static friction effect on the main terminals during the initial rotation phase.
2Ease of operation
If the locking part locks the lever to regulate rotation at the middle position, then the lever rotation is controlled to disconnect signal terminals first, but the device complexity increases
Solution Approach 1:
The patent merges the locking function with the lever structure itself. The locking part is integrated into the lever assembly, and the predetermined position is formed by the geometric relationship between the lever and the connector housing. The operation portion of the lever directly engages with the locking part at the predetermined position, combining the rotation control and locking functions into a unified structure rather than adding separate control mechanisms.
Solution Approach 2:
The lever structure serves itself by incorporating the locking mechanism within the lever assembly. The predetermined position is automatically achieved through the geometric design of the lever and connector housing interaction, without requiring external control systems. The locking part and operation portion work together inherently to regulate rotation at the correct position, making the system self-regulating.
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 configuration reduces the static friction force between main terminals, making the disengagement process easier and improving the overall operability of the power supply circuit breaker device.
Implementation Method 1
one of the pair of first terminals includes a plurality of contact pieces that are able to be elastically displaced in a direction in which elastic force acts on one of the pair of first terminals
Data Source
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AI summary
A service plug (1) includes first and second main terminals (T1, T2), first and second signal terminals (T3, T4), a lock part (26, 46) that locks a lever (40) to a second connector housing (21) to regulate rotation of the lever (40) in a state in which the lever (40) is positioned at a half-engaged position between a completely engaged position and a non-engaged position, and a lock releasing part (47) that releases a lock state. A configuration is made such that, as the lever (40) is rotated from the completely engaged position to the half-engaged position, part of a plurality of contact pieces (T21) of the second main terminal (T2) that is brought into elastic contact with the first main terminal (T1) at a position displaced in an approaching direction, and the other part of the contact pieces (T21) maintains elastic contact at a position that is not displaced in the approaching direction and a separating direction.