Inductive Position Sensor Coil Layout for Dead Band-Free Welding Control

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Solution Overview

Problem

Conventional welding systems using potentiometers and switches for on/off and output control face issues with dead band wastage, mechanical tolerance stack-up, and susceptibility to common-mode interference, leading to reduced reliability and increased costs.

Innovation Solution

The use of inductive sensors with non-uniformly spaced coils, where a conductive target's movement along the coils changes resonant frequencies, allowing for both switching and potentiometer functions, reducing dead band issues and common-mode interference through dual-coil or single-coil configurations with specific geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional potentiometers and switches are used for welding control, then on/off switching and output control functions are achieved, but dead band wastage and mechanical tolerance stack-up occur reducing reliability

Engineering Contradiction:
Improvecontrol reliabilityVSAvoiddead band wastage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces mechanical potentiometers and switches with an inductive sensor system that uses electromagnetic fields to detect the position of a conductive target. This substitution eliminates mechanical contact, dead band wastage, and mechanical tolerance stack-up, thereby improving control reliability while maintaining both on/off switching and output control functions.

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

Solution Approach 2:

The patent introduces a conductive target as an intermediary element that moves within the magnetic field of the inductive sensor. This intermediary allows the system to detect position changes without direct mechanical contact between the sensor and the control mechanism, eliminating dead band issues and mechanical wear while preserving switching and control capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If conventional switches and potentiometers are used, then control functions are achieved, but mechanical tolerance stack-up reduces precision

Engineering Contradiction:
Improveposition detection precisionVSAvoidmechanical assembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex mechanical assembly of switches and potentiometers with a simplified inductive sensor system. The electromagnetic field-based detection eliminates mechanical tolerance stack-up, providing higher position detection precision without the complexity of multiple mechanical components and their associated tolerances.

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

3Reliability

If conventional mechanical control systems are used, then switching and control functions are achieved, but susceptibility to common-mode interference increases

Engineering Contradiction:
Improvecontrol stabilityVSAvoidcommon-mode interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical control systems with an inductive sensing system that uses electromagnetic fields. This substitution eliminates susceptibility to common-mode interference that affects mechanical and electrical contact-based systems, improving control stability and reliability in electrically noisy welding environments.

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

This solution provides reliable and cost-effective switching and control in welding systems by eliminating dead band wastage and common-mode errors, enhancing the reliability and efficiency of welding control mechanisms.

Implementation Method 1

inductive sensors with non-uniformly spaced coils, where a conductive target's movement along the coils changes resonant frequencies

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

inductive position sensor with switch function

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

a conductive target's movement along the coils changes resonant frequencies

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3780392A1Inductive position sensor with switch function
Publication Date: 2021.02.17 ILLINOIS TOOL WORKS INC
  • EP3780392A1 patent drawingFigure 1a
  • EP3780392A1 patent drawingFigure 1b
  • EP3780392A1 patent drawingFigure 2a

AI summary

An inductive sensor which includes one or more inductive coils and an inductance to digital converter. The output of the inductive sensor may be used to replace the functions of a switch and a potentiometer to initiate and control various outputs in welding-type systems and applications.