Miniature Circuit Breaker Trip Mechanism with Integrated Signal Flag
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Solution Overview
Problem
Miniature circuit breakers face inefficiencies due to excessive space allocation for trip mechanism movement and separate trip flag components, which complicate assembly and increase component count.
Innovation Solution
A trip mechanism with reduced trip movement and an integrated signal flag, featuring a latching member with a central opening and catch mechanism to limit movement, and a yoke with an integral signal flag to simplify assembly and reduce component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the armature and trip lever are allowed to travel freely until stopped by other components, then the trip mechanism can complete its full movement range, but extra space must be allocated within the circuit breaker to accommodate the excess movement
Solution Approach 1:
The catch mechanism is pre-positioned on the latching member at a specific distance from the central opening. When the trip lever is released, the catch mechanism automatically catches the tip portion of the trip lever during its arcuate swing, halting its progress before it can travel the full distance to the stopping components. This preliminary halting action reduces the space required for trip movement while ensuring the trip lever completes sufficient movement to break electrical contact.
2Ease of operation
If a separate trip flag component is used to indicate tripped status, then the visual indication function is provided, but the component count increases and assembly is complicated
Solution Approach 1:
The signal flag is integrated directly into the latching member as an integral feature, eliminating the need for a separate trip flag component. The latching member, which already moves during the tripping operation, now carries the signal flag that provides visual indication when the circuit breaker is tripped. This merging of functions reduces the component count and simplifies assembly while maintaining the visual indication capability.
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 solution minimizes space requirements within the circuit breaker, reduces component count, and simplifies assembly by integrating the signal flag, while effectively indicating tripped status through optimized positioning.
Implementation Method 1
In electromechanical yokes, a bimetal strip bends in response to an overcurrent flowing through the bimetal strip. This bending of the bimetal strip distorts the yoke and forces the armature away from the trip lever.
Implementation Method 2
An electromagnetic yoke, on the other hand, has the braided wire conductor wrapped as a coil wound around the yoke. When a short-circuit current flows through the braided wire conductor, the yoke becomes highly magnetized and pulls the armature away from the trip lever.
Data Source
AI summary
A circuit breaker includes a trip mechanism having reduced trip movement and an integrated signal flag. The trip mechanism includes a spring-biased trip lever and a latching member for keeping the trip lever in an on or latched position. Upon occurrence of an abnormal current condition, the latching member is moved away from the trip lever to trip the trip mechanism. The latching member also has a catch mechanism designed to catch the trip lever after it is released, thereby halting further progress of both the trip lever and the latching member. As a result, less space is needed within the circuit breaker for trip movement compared to existing solutions. Moreover, the location of the catch mechanism on the latching member is selected such that the halting of the latching member places the integrated signal flag in an optimal viewing position within a viewing window.