Inductive Position Sensor for Welding Output and Switch Control
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Solution Overview
Problem
Conventional welding systems using potentiometers and switches for controlling output levels in welding processes face issues such as wasted potentiometer range, continuous output due to early switch activation, and mechanical tolerance stack-ups, leading to reliability and cost concerns.
Innovation Solution
The use of inductive sensors with non-uniformly spaced coils, where a conductive target's movement along the coils changes resonant frequencies, enabling both switching and output control functions, eliminating the need for separate switch and potentiometer components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional potentiometers and switches are used for controlling welding output levels, then switching and control functions can be achieved, but mechanical tolerance stack-ups and dead bands occur leading to reliability issues
Solution Approach 1:
The patent replaces the mechanical potentiometer and switch system with an inductive sensing system. The inductive sensor uses electromagnetic fields to detect the position of a conductive target, eliminating mechanical contact and associated tolerance stack-ups. This substitution of mechanical components with electromagnetic sensing directly resolves the reliability issue caused by mechanical tolerance accumulation.
Solution Approach 2:
The patent introduces a conductive target as an intermediary element that mediates between the mechanical actuator and the inductive sensor. The target's position modulates the inductive sensor's output without direct mechanical connection to the sensing elements, eliminating dead bands and improving reliability while maintaining the control function.
2Adaptability or versatility
If separate switch and potentiometer components are used, then switching and output control functions can be achieved, but device complexity and cost increase
Solution Approach 1:
The patent merges the switching and potentiometer functions into a single integrated system. The inductive sensor provides a continuous analog output that can be used for both on/off switching (by comparing against a threshold) and proportional control (by using the full range of the analog signal). This consolidation eliminates the need for separate mechanical components, reducing device complexity while maintaining full functionality.
Solution Approach 2:
The inductive sensor serves multiple functions simultaneously: it acts as both a switch (by threshold detection) and a potentiometer (by providing continuous position information). This multi-functionality allows a single component to replace what would traditionally require two separate components, simplifying the overall device architecture.
3Device complexity
If inductive sensors with non-uniformly spaced coils are used, then switching and control functions can be achieved in a single component, but coil manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by using non-uniform spacing of the inductive coils along the sensor assembly. The coil spacing is varied to create specific zones: a first zone with closer spacing for switching detection and a second zone with wider spacing for proportional control. This localized variation in coil density optimizes the sensor's performance for different control modes while maintaining manufacturability through systematic spacing patterns.
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, reducing dead bands and mechanical tolerance issues, while using a single coil or dual coils to manage common-mode errors and interference.
Implementation Method 1
a coil having a spacing that increases along a length of the coil from a first region having a first density to a second region having a second density lower than the first density; a conductive target configured to travel within a travel zone
Implementation Method 2
wherein the response of the coil to a position of the conductive target is monotonic
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
An inductive sensor which includes one or more inductive coils (136, 138) and an inductance to digital converter (142). The output of the inductive sensor is used to replace the functions of a switch and a potentiometer to initiate and control various outputs in welding-type systems and applications.