Trip Assembly Link Mechanism for Circuit Breaker Force Transmission

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Solution Overview

Problem

Existing electrical switching apparatus, such as circuit breakers, face challenges in providing sufficient tripping force to interrupt high interruption forces due to size constraints and internal component interactions, which can lead to inadequate tripping performance.

Innovation Solution

The introduction of a trip assembly comprising a yoke assembly and a link assembly, where the yoke member is coupled to the poleshaft and the linking member cooperates with the trip pin and trip D-shaft, allowing the movement of the yoke member to transmit force effectively to the trip D-shaft, enhancing tripping capability by providing additional force to overcome high interruption forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the circuit breaker size is minimized to reduce footprint, then the overall dimensions are reduced, but the tripping force becomes insufficient to overcome high interruption forces

Engineering Contradiction:
Improvecircuit breaker footprintVSAvoidtripping force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The link assembly introduces a new dimensional element by extending the force transmission path from the yoke member through the link to the trip D-shaft. This additional spatial dimension allows force multiplication without increasing the overall circuit breaker footprint, resolving the contradiction between compact size and sufficient tripping force

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The link assembly acts as an intermediary mechanical element between the yoke member and the trip D-shaft. This intermediary component transmits and amplifies the tripping force generated by the yoke member's movement, enabling sufficient force to be delivered to overcome high interruption forces while maintaining a compact circuit breaker design

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the circuit breaker is designed with compact dimensions, then the footprint is minimized, but the internal component positioning becomes constrained making it difficult to achieve requisite force

Engineering Contradiction:
Improvecircuit breaker sizeVSAvoidcomponent positioning complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The trip mechanism is segmented into distinct functional components: the yoke member for force generation, the link assembly for force transmission and amplification, and the trip D-shaft for actuation. This segmentation allows each component to be optimized for its specific function while maintaining a compact overall design, reducing the complexity of component positioning

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The link assembly utilizes an extended spatial arrangement to transmit force from the yoke member to the trip D-shaft. This dimensional approach allows proper component positioning and force transmission geometry to be achieved within a compact circuit breaker envelope, reducing positioning complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Force

If additional force is provided to the trip mechanism, then tripping capability under high interruption forces is improved, but the device complexity increases

Engineering Contradiction:
Improvetripping forceVSAvoidtrip mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The link assembly serves multiple functions: it transmits force from the yoke member, amplifies the tripping force, and provides proper mechanical coupling to the trip D-shaft. By combining these functions into a single multi-functional component, additional tripping force is achieved without proportionally increasing device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The link assembly as an intermediary component provides force amplification through its mechanical geometry. This passive force multiplication achieves the required tripping force without requiring additional active components or complex control mechanisms, thereby minimizing the increase in device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3275005B1Electrical switching apparatus and trip assembly therefor
Publication Date: 2019.06.19 EATON CORP
  • EP3275005B1 patent drawingFigure 1
  • EP3275005B1 patent drawingFigure 2
  • EP3275005B1 patent drawingFigure 3

AI summary

A trip assembly (100) is for an electrical switching apparatus (2). The electrical switching apparatus (2) includes a housing (4), separable contacts (6) enclosed by the housing (4), and an operating mechanism (8) for opening and closing the separable contacts (6). The operating mechanism (8) includes a poleshaft (16) and a trip D-shaft (18). The trip assembly (100) comprises: a yoke assembly (110) comprising a yoke member (112) and a trip pin (114) coupled to the yoke member (112), the yoke member (112) being structured to be coupled to the poleshaft (16); and a link assembly (120) comprising a linking member (122), the linking member (122) being structured to cooperate with each of the trip pin (114) and the trip D-shaft (18). When the yoke member (112) moves in response to a trip condition, the linking member (122) is structured to transmit movement of the yoke member (112) into movement of the trip D-shaft (18).