Disconnect Switch Detent Mechanism Over-Rotation Protection

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Solution Overview

Problem

Electrical disconnect switches are prone to damage from over-rotation of the handle assembly, which can cause excessive stress on the load switch, leading to potential damage during operation in harsh environments.

Innovation Solution

Incorporating a detent mechanism between the handle assembly and the load switch, which allows the handle to decouple from the load switch when excessive force or torque is applied, preventing damage by allowing the handle to freely rotate until the detent re-engages, thus protecting the load switch from over-rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the handle assembly is rigidly coupled to the load switch, then the switch operates reliably, but the load switch is vulnerable to damage from over-rotation

Engineering Contradiction:

Improveoperational reliabilityVSAvoidresistance to over-rotation damage

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The coupling between the handle assembly and load switch is segmented into two functional parts: a drive mechanism for normal operation and a detent mechanism for protection. The detent mechanism acts as a separate protective element that can disengage independently, dividing the coupling function into operational and protective segments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The detent mechanism serves as an intermediary protective element between the handle assembly and the load switch. It mediates the force transmission, allowing normal operation while blocking excessive force from reaching the load switch, thus protecting the vulnerable component.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the handle assembly is decoupled during over-rotation, then the load switch is protected, but the coupling mechanism becomes more complex

Engineering Contradiction:

Improveprotection from over-rotation damageVSAvoidcoupling mechanism complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The detent mechanism is designed to automatically engage and disengage based on the applied force, without requiring external control or complex sensing systems. The mechanism serves itself by using the excessive force directly to trigger its own disengagement, simplifying the overall system despite adding protective functionality.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The coupling mechanism transitions between two states based on the force parameter: engaged state for normal operation and disengaged state for over-rotation protection. This parameter-based state change allows simple binary behavior (coupled/not coupled) rather than requiring complex continuous control.

Inventive Principle:

Principle #35Parameter changes

3Strength

If the detent mechanism allows free rotation during over-rotation, then damage is prevented, but the handle assembly may become misaligned

Engineering Contradiction:

Improveprotection from mechanical stressVSAvoidhandle-switch alignment

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

Instead of trying to prevent free rotation and maintain alignment through complex constraints, the design inverts the approach by allowing free rotation and using the detent's re-engagement geometry to automatically restore proper alignment. The protection mechanism becomes the alignment mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10923300B2Disconnect switch with a detent mechanism to protect against over-rotation

Publication Date: 2021.02.16 LEVITON MFG CO INC

AI summary

An electrical disconnect switch including an over-rotation protective feature to protect the load switch from damage is disclosed. The electrical disconnect switch may include an enclosure, a load switch, and a handle assembly coupled to the load switch. The disconnect switch may include a detent between the handle assembly and the load switch so that during excessive rotation or torqueing the handle assembly is permitted to decouple or break-away from the load switch to prevent excessive stress from being transferred to the load switch and thus prevent any damage to the load switch.