Magnetically Coupled Ground Reference Probe for Safe Hands-Free Operation

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Solution Overview

Problem

In high-energy environments, existing measurement equipment requires a ground reference that is hazardous and difficult to handle with bulky protective gear, limiting the operator's ability to perform measurements efficiently.

Innovation Solution

A magnetically coupled ground reference probe with an insulative housing and a movable conductive magnet, biased by a compression spring, which automatically retracts into the housing when not in use, allowing safe and easy handling and providing a hands-free ground connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a traditional test lead with metal probe is used for ground connection, then electrical measurement can be performed, but the operator needs to use two hands to hold probes which reduces productivity and efficiency

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidhands-free operation
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The ground probe is designed to automatically attach to ferromagnetic surfaces through magnetic attraction and self-retract when not in use. The magnet automatically engages with the panel ground and retracts into the insulative housing when lifted, eliminating the need for continuous manual holding and enabling hands-free operation during measurements.

Inventive Principle:
Principle #25Self-service

2Reliability

If a metal probe is used for ground connection, then electrical connectivity is achieved, but the metal connection points pose safety hazards in high-energy environments

Engineering Contradiction:
ImprovesafetyVSAvoidshort circuit risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An insulative housing made of non-conductive material serves as an intermediary between the operator and the conductive magnet. The housing completely encloses the magnet during handling and storage, preventing accidental contact with energized circuits. The magnet only exposes its magnetic pole face when attached to the panel ground, eliminating short circuit hazards while maintaining electrical connectivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The conductive magnet is extracted from traditional exposed probe designs and enclosed within an insulative housing. This separation allows the magnet to provide ground connection functionality while being protected by the insulative barrier, removing the safety hazard associated with exposed metal contacts in high-energy environments.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If a magnet is used to provide ground connection, then hands-free operation is enabled, but the magnet needs a mechanism to retract which increases device complexity

Engineering Contradiction:
Improvehands-free operationVSAvoidretract mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The magnet is designed to be movable within the housing rather than fixed, allowing it to dynamically retract when not in use. A spring mechanism provides the retracting force that returns the magnet to its stored position within the housing when magnetic attraction is released, enabling automatic retraction without complex active control systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The retract mechanism uses passive mechanical elements (spring and magnetic attraction) instead of active mechanical systems with motors or actuators. The spring provides continuous retracting force, and the magnetic attraction itself serves as the engaging mechanism, eliminating the need for complex control systems while achieving automatic retraction and engagement.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 probe ensures a safe and effective ground connection while allowing the operator to use both hands for other tasks, minimizing the risk of short circuits and enabling efficient measurements even when wearing bulky gloves.

Implementation Method 1

a biasing actuator operatively coupled to bias the magnet in the raised position, the biasing actuator exerting an upward force on the magnet

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a downward magnetic force exerted on the magnet when the bottom rim of the housing is disposed adjacent a ferromagnetic material

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP3321695B1Magnetically coupled ground reference probe
Publication Date: 2019.08.21 FLUKE CORP
  • EP3321695B1 patent drawingFigure 1
  • EP3321695B1 patent drawingFigure 2~3
  • EP3321695B1 patent drawingFigure 4~5

AI summary

Systems and methods of providing a magnetically coupled ground reference probe for use with test equipment (e.g., digital multimeters (DMMs)). The magnetically coupled ground reference probes disclosed herein may be used instead of a typical test probe or alligator clip. A magnetically coupled ground reference probe may be provided which includes an insulative housing surrounding a conductive magnet (e.g., permanent magnet, electromagnet). The magnet may autonomously retract into a cavity of the insulative housing when not coupled to a ground reference so that the magnet does not contact a high potential source when being handled by the operator. In at least some implementations, at least a portion of the insulation material of the housing may be compressible to allow the magnet to come into physical contact with a ground reference surface while providing a sufficient creepage and clearance path.