Welding Torch Voltage Sensing via Electrode Wire

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Solution Overview

Problem

Conventional voltage sense leads in welding systems are prone to inaccuracies due to voltage drops across torch components and are susceptible to damage from handling and articulation, making it difficult to accurately measure the voltage across the welding arc.

Innovation Solution

The system uses the welding electrode wire as a voltage sense lead, electrically insulating it from the torch conductor and feeder frame except at the point of power transfer, allowing for more accurate measurement of arc voltage by picking up the voltage potential within the wire feeder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional voltage sense leads are used to measure arc voltage, then voltage measurement can be performed, but measurement precision deteriorates due to voltage drops across torch components

Engineering Contradiction:
Improvearc voltage measurement accuracyVSAvoidvoltage drop across torch components
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent extracts the voltage sensing function from the conventional torch-mounted sense leads and relocates it to the wire feeder. By measuring voltage at the wire feeder location rather than through torch components, the system eliminates voltage drops across goosenecks, contact tips, and other torch elements, thereby improving measurement precision without energy loss

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces the electrode wire as an intermediary conductor that carries both welding current and voltage sensing signals. The wire acts as a mediator between the power source and the arc, allowing voltage measurement at the wire feeder while maintaining electrical continuity for the welding process

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If conventional voltage sense leads are used in the torch, then voltage sensing is enabled, but reliability deteriorates due to damage from handling and articulation

Engineering Contradiction:
Improvevoltage sense lead durabilityVSAvoidhandling and articulation damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the vulnerable voltage sense leads from the torch assembly, eliminating them from the moving and articulated portions of the system. By relocating voltage sensing to the stationary wire feeder, the system eliminates the reliability issues caused by repeated handling, bending, and articulation of sense leads

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent utilizes the electrode wire itself, which is already present and necessary for the welding process, to serve the dual function of both welding material delivery and voltage sensing. This eliminates the need for separate sense leads that would be susceptible to damage

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the electrode wire is electrically insulated from the torch conductor along its length, then measurement precision improves, but device complexity increases due to insulation requirements

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoidelectrical insulation structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the electrode wire multi-functional by having it serve both as the welding consumable and as the voltage sensing conductor. The wire's existing insulation, designed for welding purposes, simultaneously provides the electrical isolation needed for accurate voltage measurement, eliminating the need for additional insulation structures

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

Solution Approach 2:

The patent merges the voltage sensing function with the electrode wire delivery system. By combining these two functions into a single integrated approach where the wire serves both purposes, the system reduces overall complexity rather than adding separate insulated sensing conductors

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

This approach provides a more accurate measurement of arc voltage, reducing errors caused by torch component voltage drops and handling damage, and maintains measurement accuracy even during torch articulation.

Implementation Method 1

the wire liner being electrically insulated from the conductor along a length of the wire liner and being electrically insulated from the connector

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP3744462A1Welding torch and wire feeder that use electrode wire for voltage sensing
Publication Date: 2020.12.02 ILLINOIS TOOL WORKS INC
  • EP3744462A1 patent drawingFigure 1
  • EP3744462A1 patent drawingFigure 2
  • EP3744462A1 patent drawingFigure 3

AI summary

An example welding torch includes: a contact tip configured to conduct welding-type current to a wire electrode; a conductor configured to transfer welding-type current from a welding-type power source to the contact tip; a connector configured to couple the conductor to a wire feeder to receive the welding-type current, the connector comprising an inlet configured to receive the wire electrode from a wire feeder; and a wire liner configured to deliver the wire electrode from the wire feeder to the contact tip via the inlet of the connector, the wire liner being electrically insulated from the conductor along a length of the wire liner and being electrically insulated from the connector.