Pole Shaft Catch Assembly for Circuit Breaker Rebound Control
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Solution Overview
Problem
Molded case circuit breakers face challenges in preventing rebounding of the pole shaft during high current interruptions due to limited space, existing designs failing to effectively incorporate a suitable mechanism to address this issue.
Innovation Solution
A pole shaft catch assembly with a catch arm and trigger arrangement, utilizing a torsion spring to bias the catch arm towards a disengaged position, which engages to restrict the yoke assembly and pole shaft from rebounding by translating movement of the yoke assembly into a corresponding movement of the catch arm, effectively arresting undesirable rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional anti-bouncer mechanism is incorporated into molded case circuit breakers, then pole shaft rebounding is prevented, but the device complexity increases and available space is insufficient
Solution Approach 1:
The catch arm is pivotally mounted on the yoke assembly, nesting the catch mechanism within the existing yoke structure. The trigger member engages with the catch arm, creating a compact nested arrangement that prevents pole shaft rebounding without adding significant complexity or requiring additional space beyond the yoke assembly area.
Solution Approach 2:
The trigger member acts as an intermediary between the yoke assembly movement and the catch arm engagement. When the yoke assembly moves during circuit interruption, the trigger member translates this movement to engage or disengage the catch arm, providing a mechanical mediation that prevents rebounding while maintaining simplicity.
2Reliability
If a catch mechanism is added to prevent pole shaft rebounding, then operational reliability improves, but the manufacturing complexity increases
Solution Approach 1:
The catch arm is pivotally mounted on the yoke assembly, nesting the catch mechanism within the existing yoke structure. The trigger member engages with the catch arm, creating a compact nested arrangement that prevents pole shaft rebounding without adding significant complexity or requiring additional space beyond the yoke assembly area.
Solution Approach 2:
The catch assembly is segmented into distinct components: the catch arm, the trigger member, and the torsion spring. This segmentation allows each component to be manufactured separately using standard machining processes, then assembled together, simplifying both manufacturing and maintenance while ensuring reliable rebound prevention.
3Stability of the object's composition
If space near the pole shaft is used for a rebound prevention mechanism, then pole shaft stability is improved, but the available space for other components is reduced
Solution Approach 1:
The catch arm is pivotally mounted on the yoke assembly, nesting the catch mechanism within the existing yoke structure. The trigger member engages with the catch arm, creating a compact nested arrangement that prevents pole shaft rebounding without adding significant complexity or requiring additional space beyond the yoke assembly area.
Solution Approach 2:
The catch mechanism operates in a dimensional space defined by the angular rotation of the catch arm and the linear movement of the trigger member, rather than occupying additional radial or axial space near the pole shaft. This allows the mechanism to provide stability without encroaching on the limited space surrounding the pole shaft.
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 pole shaft catch assembly effectively prevents rebounding of the pole shaft during high current interruptions, allowing the circuit breaker to reset and maintain operation, even in constrained spaces near the pole shaft.
Implementation Method 1
utilizing a torsion spring to bias the catch arm towards a disengaged position
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A pole shaft catch assembly (100) is for an electrical switching apparatus (2), such as a circuit breaker. The circuit breaker includes a housing (4), separable contacts (6,8) enclosed by the housing (4), and an operating mechanism (10) for opening and closing the separable contacts (6,8). The operating mechanism (10) includes a pole shaft (12) pivotably coupled to the housing (4) and a yoke assembly (200) coupled to the pole shaft (12). The pole shaft catch assembly (100) includes a catch arm (102). The catch arm (102) moves between an engaged position in which the catch arm (102) engages the yoke assembly (200) to restrict movement of the yoke assembly (200) and the pole shaft (12), and a disengaged position in which the catch arm (102) disengages the yoke assembly (200). A biasing element (140) biases the catch arm (102) toward the disengaged position. A trigger (180) translates movement of the yoke assembly (200) into movement of the catch arm (102).