Vibration-Isolated Weft Thread Tension Sensor

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Solution Overview

Problem

Existing sensor devices for sensing weft thread tension on weaving machines suffer from high noise levels due to vibrations, making it difficult to accurately measure low tensions and variations, which can lead to inaccurate control of the weft thread brake and display of tension values.

Innovation Solution

A sensor device with a mounting arrangement that includes elastic damping elements to isolate the sensor unit from vibrations, allowing for precise measurement of weft thread tension by reducing noise in the signal, and a design that minimizes deflection angle and wear, using a bendable sensing blade with strain gauges and a contact area that protrudes into the weft thread path between the weft presenter and gripper.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensor unit is mounted directly to the weaving machine, then the sensor is stable and easy to install, but the sensor is exposed to high vibrations causing high noise levels and inaccurate measurements

Engineering Contradiction:
Improvetension measurement accuracyVSAvoidvibration noise
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a mounting arrangement as an intermediary component between the sensor unit and the weaving machine. This mounting arrangement includes vibration isolation elements (elastic elements, dampers, or springs) that mediate the connection, allowing the sensor to be mounted while filtering out harmful vibrations from the weaving machine, thus reducing noise and improving measurement accuracy without requiring direct mounting.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the contact area protrudes into the weft thread path, then the sensor can detect tension effectively, but the deflection angle increases causing additional wear and potential interference with thread running

Engineering Contradiction:
Improvetension detection capabilityVSAvoidthread wear and interference
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by designing the contact area with specific local properties - it has a curved or rounded contact surface that locally adapts to the thread path. This local geometric adaptation allows the sensor to detect tension through controlled contact while minimizing the deflection angle and reducing wear at the specific contact point, without affecting the overall thread running path.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The mounting arrangement is designed to be dynamically adjustable in terms of vibration isolation. The elastic elements or dampers can adapt to different vibration levels and frequencies from the weaving machine, providing optimal isolation under varying operating conditions. This dynamic adaptation ensures consistent measurement precision while maintaining minimal interference with the weft thread throughout the weaving cycle.

Inventive Principle:
Principle #15Dynamics

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 effectively reduces noise from machine vibrations, enabling accurate sensing of low tensions and variations, improving the control of the weft thread brake and providing reliable tension data for monitoring and control units.

Implementation Method 1

the mounting arrangement comprises an elastic damping element adapted for isolating the sensor unit mounted to the weaving machine from vibrations of the weaving machine

Methodology Applied
Scientific EffectVibration isolation: Damping

Implementation Method 2

the mounting arrangement comprises an elastic damping element adapted for isolating the sensor unit mounted to the weaving machine from vibrations of the weaving machine

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a sensor unit and a mounting arrangement, which sensor unit has a contact area and is adapted to generate a response signal in response to a force applied by the weft thread at the contact area

Methodology Applied
Scientific EffectStrain measurement: Deformation

Data Source

PatentEP3967801A1Device and method for sensing a tension in a thread, and method for mounting a sensor unit
Publication Date: 2022.03.16 PICANOL NV
  • EP3967801A1 patent drawingFigure 1
  • EP3967801A1 patent drawingFigure 2
  • EP3967801A1 patent drawingFigure 3

AI summary

The invention relates to a sensor device and a method for sensing a tension in a weft thread (1) between a weft presenter (4) and a gripper (6) on a gripper weaving machine (100), the sensor device (10) comprising a sensor unit (20) with a contact area (21), which sensor unit (20) is adapted to generate a response signal in response to a force applied by the weft thread (1) at the contact area (21), and a mounting arrangement (22) adapted for mounting the sensor unit (20) to the weaving machine (100) in a region between the weft presenter (4) and a shed (5), wherein the mounting arrangement (22) comprises an elastic damping element (25) adapted for isolating the sensor unit (20) mounted to the weaving machine (100) from vibrations of the weaving machine (100). The invention further relates to a weaving machine with a sensor unit for sensing a tension in a weft thread, and to a method for mounting a sensor unit to a weaving machine.