Circuit Breaker Operating Mechanism Contact Force Adjustment

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing operating mechanisms for multi-pole circuit breakers lack a compact and efficient method for adjusting contact force, which is crucial for ensuring equal contact force across all circuit breakers in a three-phase installation, affecting the correct operation of medium voltage switchgear.

Innovation Solution

The operating mechanism features a spring holder with a screw connection for adjustable relative positioning, allowing precise and continuous adjustment of the compression spring force, combined with a compact design using a cylindrical body and a spring guide, enabling easy access and locking of the force setting, and a drive plate for simultaneous operation of multiple circuit breakers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional adjustment mechanism is used for contact force, then the contact force can be adjusted, but the structure becomes complex and the adjustment is not compact

Engineering Contradiction:
Improvecontact force adjustmentVSAvoidadjustment mechanism structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The adjustment mechanism is segmented into distinct functional components: a spring holder for mounting the compression spring, a spring holder top for positioning adjustment, and a locking device for fixation. This segmentation allows each component to perform its specific function efficiently while keeping the overall structure compact and manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The compression spring is positioned inside the spring holder, and the spring holder top is connected to the spring holder in a nested arrangement. This nesting principle reduces the overall volume of the adjustment mechanism and creates a compact structure that maintains all necessary functional capabilities.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Measurement precision

If the relative position of spring holder and spring holder top is adjustable, then contact force can be precisely set, but the mechanism requires more components for adjustment and locking

Engineering Contradiction:
Improvecontact force setting precisionVSAvoidadjustment and locking components
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The spring holder top is designed to be movable relative to the spring holder during the adjustment phase, allowing continuous variation of the compression spring force. After adjustment, the locking device engages to fix the position dynamically. This dynamic design enables precise contact force setting while using a relatively simple locking mechanism.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The contact force is adjusted by changing the positional parameter of the spring holder top relative to the spring holder. By moving the spring holder top along the spring holder, the compression distance of the spring is modified, thereby changing the contact force parameter continuously until the desired precision is achieved.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If a compact design is used with cylindrical body and spring guide, then the operating mechanism volume is reduced, but the adjustment accessibility may be limited

Engineering Contradiction:
Improveoperating mechanism volumeVSAvoidadjustment accessibility
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The adjustment mechanism is designed as a segmented assembly that can be accessed from the front of the device. The spring holder, spring holder top, and locking device are arranged in a way that allows adjustment operations to be performed on the accessible front side, even within the compact cylindrical structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking device acts as an intermediary component that provides a simple interface for both adjustment and locking operations. It mediates between the user's adjustment action and the internal spring holder top positioning, making the compact mechanism easily adjustable through a simple front-accessible interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for accurate and efficient adjustment of contact force, ensuring consistent operation across all circuit breakers, maintaining the necessary operational characteristics while achieving a compact and ergonomic design.

Implementation Method 1

a compression spring (103) exerting a force on the operating shaft (109) in the ON state of the operating mechanism

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2037475B8Operating mechanism with adjustment of contact force
Publication Date: 2012.03.14 EATON IND NETHERLANDS

AI summary

Operating mechanism for operating a multi-pole circuit breaker assembly. For each circuit breaker (18) in the multi-pole circuit breaker assembly, the following elements are provided: a connection assembly for connection to an operating shaft (109) of the circuit breaker (18), an actuator (4) for changing between an ON and OFF state of the operating mechanism, a translation assembly for transferring a movement of the actuator (4) to the connection assembly, and a compression spring (103) exerting a force on the operating shaft (109) in the ON state of the operating mechanism. The force exerted by the compression spring (103) is adjustable by a force setting assembly (100, 104) in a continuous manner.