Circuit Disconnect Knob Locking Without Movable Links

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Solution Overview

Problem

Existing electrical circuit disconnect devices are complex, costly, and lack robust locking mechanisms, making them prone to accidental operation and requiring movable locking links that can break under torque.

Innovation Solution

A device with an integrated actuation knob that can be locked directly to the housing using apertures, eliminating the need for movable locking links and providing redundant locking points, ensuring the knob cannot be easily removed or overridden.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If movable locking links are used to lock the device, then the device can be locked to prevent accidental operation, but the locking mechanism becomes complex and the locking links can break under torque

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the movable locking links from the system entirely and replaces them with a static aperture-based locking system. The housing contains fixed apertures that align with apertures in the knob at specific positions, eliminating the need for moving locking components that can break.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using movable links that actively engage to lock the device, the patent inverts the approach by using fixed apertures that passively receive locking means. The locking mechanism works by the absence of movement rather than through active engagement of moving parts.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If external handles with external locking arrangements are used, then the device can be locked, but the manufacturing and assembly cost increases

Engineering Contradiction:
Improvelocking capabilityVSAvoidmanufacturing and assembly cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the locking mechanism directly into the housing and knob assembly. The apertures are integrated into the housing structure and the knob, eliminating the need for separate external locking arrangements and reducing the number of discrete components that need to be manufactured and assembled.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing serves multiple functions: it encloses the electrical components and simultaneously provides the locking mechanism through its integrated apertures. The knob also serves dual purposes as the actuation mechanism and as part of the locking system through its aligned apertures.

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

3Ease of operation

If the knob can be easily removed from the front of the device, then the device is easier to operate, but the device becomes vulnerable to unauthorized override

Engineering Contradiction:
Improveknob accessibilityVSAvoidprotection against unauthorized operation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent nests the locking mechanism within the housing structure itself. The apertures are formed directly in the housing body, and the locking means extend through these apertures to secure the knob in place, creating a layered protection system where the housing provides both enclosure and locking functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4338188B1Device for disconnecting an electrical circuit
Publication Date: 2026.02.25 EATON INTELLIGENT POWER LTD
  • EP4338188B1 patent drawingFigure 1A
  • EP4338188B1 patent drawingFigure 1B
  • EP4338188B1 patent drawingFigure 2A-1~2A-2

AI summary

Provided herein is a device comprising: a contact mechanism (or switch); an actuation knob; and a housing. The contact mechanism (or switch) comprises: an actuating mechanism; a first conductor; a second conductor; and a moveable contact moveable, by the actuating mechanism, between a first, closed, position in which a current conduction path is defined through the first, second and moveable conductors of the contact mechanism and a second, open, position in which no current conduction path is defined. The actuation knob (or knob) comprises: a first side configured to drive the actuating mechanism upon rotation of the actuation knob, the first side comprising a cam portion which directly engages with the actuating mechanism; a second side opposite the first side; and an engagement portion protruding from the second side and configured for engagement by a user. The housing encloses both the contact mechanism and the first side of the actuation knob, the engagement portion configured to protrude through an opening in the housing. The actuation knob is configured to rotate within the housing in response to engagement by a user. A system comprising the device and an electrical circuit configured to be coupled to the first and second conductors of the contact mechanism is also provided herein.