Collapsible Link Mechanism for Circuit Breaker Tripping
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Solution Overview
Problem
Molded case circuit breakers require a mechanism to trip safely and reliably under overcurrent conditions without manual intervention, addressing the historical issue of fuse blowouts and fire hazards due to inadequate circuit protection.
Innovation Solution
A collapsible link mechanism within the circuit breaker that pivots upon detection of trip conditions, utilizing a torsion spring to maintain the default position and a notch structure to receive angular forces, causing the circuit breaker to trip and unlatch, thereby opening the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional trip mechanism is used in circuit breakers, then the circuit breaker can open under overcurrent conditions, but the mechanism requires significant force to trip and may not reliably prevent fire hazards
Solution Approach 1:
The patent applies dynamics by making the link collapsible rather than rigid. The link transitions from an extended position during normal operation to a collapsed position during tripping, allowing the mechanism to adapt its structural configuration dynamically. This dynamic transformation enables the system to require minimal force for tripping while maintaining reliability in circuit protection.
Solution Approach 2:
The patent segments the trip mechanism into distinct functional components: the armature, the collapsible link, and the latch. The collapsible link acts as an intermediary element that transmits and amplifies the tripping force from the armature to the latch mechanism. This segmentation allows each component to be optimized for its specific function, reducing the overall force required while maintaining reliable operation.
2Force
If a collapsible link mechanism is implemented, then minimal force is required to trip the circuit breaker, but the mechanism complexity increases
Solution Approach 1:
The patent merges the functions of force transmission and mechanical amplification into a single collapsible link component. Rather than using separate levers, springs, and cam mechanisms, the collapsible link performs multiple functions: it transmits force from the armature, amplifies the tripping motion, and engages/disengages the latch. This merging reduces the number of parts and simplifies the overall mechanism despite its enhanced functionality.
Solution Approach 2:
The patent utilizes parameter changes in the geometric configuration of the collapsible link. The link changes its effective length and angular position as it transitions between extended and collapsed states. By carefully designing the geometry and pivot points, the mechanism achieves mechanical advantage and force amplification without requiring additional complex components. The parameter changes in shape and position enable the simplified structure to perform complex functions.
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
Enables safe, reliable, and resettable tripping of the circuit breaker under overcurrent conditions, ensuring electrical safety and preventing fire hazards by automatically opening the circuit without requiring part replacement.
Implementation Method 1
a torsion spring adapted to maintain the flat substantially oval shaped rigid structure in a default position
Implementation Method 2
a torsion spring adapted to maintain the flat substantially oval shaped rigid structure in a default position
Implementation Method 3
the armature having a first end and a second end, the first end pivotally connected with the housing such that the armature is adapted to pivotally move upon detection of the one or more trip conditions
Implementation Method 4
a collapsible link hingedly connected with the second end of the armature, the collapsible link adapted to swingably collapse upon detection of the one or more trip conditions
Data Source
AI summary
A device can be installed inside a circuit breaker assembly to reduce friction between an armature and a cradle, which in turn, allows the circuit breaker to trip without requiring significant force. Such device can be a collapsible mechanism configured to swivel about its hinged connection to the armature.