Extended Drive Plate Rotary Handle for Circuit Breaker Safety

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional rotary handle mechanisms for circuit breakers do not ensure safe operation when electrical contacts are welded closed, as they rely on proper handle positioning and force limits, which can lead to accidental engagement and safety hazards due to wear and misinterpretation of the contact status.

Innovation Solution

An extended drive-plate deliberate action rotary handle mechanism that engages a circuit breaker only upon deliberate action by the operator, utilizing a torsion spring and cylinder system to prevent accidental activation, ensuring safe operation and compliance with NFPA 79 standards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional handle mechanisms rely on proper handle positioning and force limits to prevent locking during Positive OFF, then the mechanism can operate under standard conditions, but with wear the handle position approaches the locked position creating safety hazards

Engineering Contradiction:

Improvesafety of handle mechanismVSAvoidhandle position stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The drive plate groove is designed to preemptively prevent handle engagement with the drive shaft under normal conditions. The groove geometry creates a mechanical constraint that actively works against accidental locking, requiring deliberate operator action (pushing the handle toward the drive shaft) to overcome this preliminary anti-action and engage the circuit breaker.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The drive plate groove acts as an intermediary mechanical element between the handle and the drive shaft. It mediates the interaction by allowing free rotation in normal conditions while blocking engagement unless the handle is deliberately pushed toward the drive shaft, thus preventing accidental activation while enabling intentional operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the handle mechanism allows easy operation for normal switching, then operational efficiency is improved, but accidental activation may occur due to improper positioning or wear

Engineering Contradiction:

Improvehandle operation easeVSAvoidaccidental activation risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The drive plate groove provides different mechanical characteristics at different locations and orientations. Along the normal rotation path, the groove allows free movement for easy operation. However, when the handle is pushed toward the drive shaft (deliberate action), the groove geometry changes locally to enable engagement, thus providing ease of operation for normal use while preventing accidental activation.

Inventive Principle:

Principle #3Local quality

3Productivity

If the handle can be accidentally pushed without deliberate action, then operational speed is maintained, but the circuit breaker may activate when it should remain off creating safety hazards

Engineering Contradiction:

Improveoperational speedVSAvoidsafe operation assurance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The drive plate groove creates a preliminary mechanical barrier that prevents accidental activation while maintaining operational speed for intentional actions. The groove is designed to block the handle from engaging the drive shaft unless deliberate force is applied to push the handle toward the drive shaft, thus preventing harmful accidental activations while allowing rapid intentional operation.

Inventive Principle:

Principle #9Preliminary anti-action

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 mechanism ensures safe and intentional operation of circuit breakers by requiring deliberate action to engage the handle, preventing accidental activation and maintaining safety even when the electrical enclosure door is open, thus meeting NFPA 79 standards.

Implementation Method 1

utilizing a torsion spring and cylinder system to prevent accidental activation

Methodology Applied

Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentUS8115127B2Extended drive plate deliberate action rotary handle

Publication Date: 2012.02.14 SIEMENS INDUSTRY INC

AI summary

The present invention relates generally to a rotary handle. More particularly, the invention encompasses a deliberate action rotary handle. The invention further includes an extended drive-plate deliberate action rotary handle, such that to turn on a component, such as, a circuit breaker, requires a deliberate manual action by the user. If a deliberate action is not taken by a user but the handle is accidentally pushed then the handle does not engage with a drive shaft and the handle moves to an outer edge of a drive plate thus preventing the engagement of the handle with the other components to turn on the component.