Circuit Breaker Interlock With Mechanical Latching

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Solution Overview

Problem

Existing lockout mechanisms for circuit breakers require manual intervention and continuous energization to maintain the lockout state, leading to unwanted changes during power or communication losses, causing potential damage to the power distribution system.

Innovation Solution

An interlock device mechanically interconnected with a circuit breaker, featuring a lockout actuator, reset actuator, and latching assembly that toggles between locked and non-locked positions, ensuring the circuit breaker trips and prevents closure only when intentionally reset, using a combination of levers, pins, and solenoids to maintain the lockout state without continuous energization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous energization of the solenoid is used to maintain the lockout state, then the lockout state is maintained reliably, but energy consumption increases and the system becomes vulnerable to power loss

Engineering Contradiction:
Improvelockout state maintenanceVSAvoidsolenoid energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The lockout mechanism uses a latched solenoid design where the solenoid energizes the plunger to the lockout position and then latches it there mechanically. The plunger maintains contact with the lever arm through mechanical engagement, allowing the system to maintain the lockout state without continuous energization. This eliminates the need for continuous power supply while maintaining reliable lockout state.

Inventive Principle:
Principle #25Self-service

2Reliability

If manual intervention is required to reset the lockout mechanism, then the lockout state is securely maintained, but operational complexity and time increase

Engineering Contradiction:
Improvelockout state securityVSAvoidreset operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The reset mechanism automatically detects when the fault condition is cleared and self-resets the lockout state. The system monitors the circuit breaker status and when it returns to normal operation, the solenoid is re-energized to reset the plunger and lever arm, eliminating the need for manual intervention while maintaining secure lockout during fault conditions.

Inventive Principle:
Principle #25Self-service

3Reliability

If the lockout mechanism uses a latched solenoid design, then power loss vulnerability is reduced, but device complexity increases

Engineering Contradiction:
Improvepower loss resistanceVSAvoidlatching assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the lockout and reset functions into a single integrated latching assembly. The lever arm serves dual purposes: it engages with the plunger to maintain lockout position and also acts as the reset mechanism when moved by the solenoid. This merging of functions reduces the number of separate components needed compared to traditional designs with separate lockout and reset mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

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 interlock device reduces the risk of damage by automatically maintaining the lockout state during power or communication losses, preventing unintended changes and ensuring safe operation without manual intervention or continuous power supply.

Implementation Method 1

These lockout mechanisms also include solenoids having biased plungers that immediately return to their home position when the solenoid is de-energized

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Implementation Method 2

solenoids having biased plungers that immediately return to their home position when the solenoid is de-energized

Methodology Applied
Scientific EffectElastic force: Spring

Data Source

PatentEP2110839B1Electromechanical Interlock For Electrical Protection Devices
Publication Date: 2016.03.23 GENERAL ELECTRIC CO
  • EP2110839B1 patent drawingFigure 1
  • EP2110839B1 patent drawingFigure 2~5
  • EP2110839B1 patent drawingFigure 6

AI summary

An interlock is presented which may be mechanically interconnected with a circuit breaker. The interlock (10) toggles between a locked out position that causes the circuit breaker to trip and prevents closure thereof and a non-locked out position wherein the circuit breaker functions. The interlock includes a frame (12), a lockout actuator (44) supported by the frame, a reset actuator (48) also supported by the frame and a latching assembly (42). The latching assembly includes a lockout lever (46) that is responsive to movement of the lockout actuator that is pivotably supported by the frame and a lockout trip rod responsive to movement of the lockout actuator. Also provided is a reset lever (50) that is responsive to movement of the reset actuator and that is also pivotably supported by the frame. The reset lever is configured to prevent movement of the lockout actuator without movement of the reset lever and wherein the lockout trip rod is configured for movement between a locked out position and a non-locked out position.