Yarn Tension Sensor Using Inductive Coil for Thermal Stability
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Solution Overview
Problem
Conventional yarn tension sensors for textile machines are either complex and expensive due to resistive strain gauges or prone to thermal drift issues with Hall effect sensors, necessitating frequent resets and complicating the weaving process.
Innovation Solution
A yarn tension sensor utilizing a plate-like carrier with spiral coils and a flexible arm mechanism that measures tension through variations in self-inductance, minimizing thermal drift effects and providing high precision with a simpler and stronger structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistive strain gauges are used for yarn tension measurement, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the mechanical resistive strain gauge system with an electromagnetic induction system using a coil and magnetic circuit. The tension measurement is achieved through changes in magnetic flux and induced voltage rather than mechanical strain on resistive elements, thereby simplifying the overall device structure while maintaining measurement capability
Solution Approach 2:
The patent changes the measurement parameter from electrical resistance (in strain gauges) to electromagnetic induction parameters (voltage induced in coil). By measuring the voltage induced in the coil due to changes in magnetic flux caused by yarn tension, the system achieves measurement precision without the complexity of Wheatstone bridge circuits and strain gauge installations
2Measurement precision
If Hall effect sensors are used for yarn tension measurement, then measurement precision is improved, but thermal stability deteriorates due to thermal drift
Solution Approach 1:
The patent replaces the Hall effect sensor (which is susceptible to thermal drift) with an electromagnetic induction-based measurement system. The new system measures tension through changes in magnetic flux and induced voltage in a coil, which are less sensitive to temperature variations, thereby improving thermal stability while maintaining measurement precision
Solution Approach 2:
The patent converts the potential harm of temperature variations into a beneficial measurement mechanism. Instead of using temperature-sensitive Hall effect sensors, the system uses electromagnetic induction where the measurement is based on magnetic flux changes caused by tension-induced dimensional changes in the magnetic circuit, making the measurement inherently more stable against thermal effects
3Measurement precision
If Hall effect sensors are used for yarn tension measurement, then measurement precision is improved, but operational complexity increases due to periodic reset requirements
Solution Approach 1:
The patent replaces the Hall effect sensor system that requires periodic resetting with a continuous electromagnetic induction measurement system. The coil-based system continuously measures tension through induced voltage without drift, eliminating the need for manual or automated reset operations and thereby simplifying the operational process
Solution Approach 2:
The patent implements a self-adjusting measurement system where the electromagnetic induction automatically compensates for any drift or environmental changes. The system continuously self-calibrates through the physical principles of electromagnetic induction, eliminating the need for external intervention or periodic resets by operators
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 solution achieves precise yarn tension measurement with reduced thermal sensitivity and increased robustness, enhancing textile production quality and reliability by maintaining consistent tension without the need for frequent resets.
Implementation Method 1
measures tension through variations in self-inductance
Implementation Method 2
spiral coils on two respective opposite sides 16a, 16b thereof
Data Source
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Figure 8~10
AI summary
A contact element (19) which is adapted to be slideably engaged by a yarn (Y) is moveably sustained with respect to a support (12) in relation to the fluctuations of tension of the yarn (Y), the contact element (19) being integral with a reference element (32) which is made of a conductive material and operatively faces a spiral coil (18a, 18b) driven by a control unit (16) in order to generate a magnetic field of constant strength, which interacts with the reference element (32) in such a manner that the inductance (L(d)) and the resistance (R(d)) of the spiral coil (18a, 18b) vary as a function of the distance from the reference element (32), the control unit being programmed to calculate the tension of the yarn as a function of the variations of inductance (L(d)) and of resistance (R(d).