Double control loop method and device for ensuring constant tension yarn feed to a textile machine

Abstract

A method for feeding a yarn (F) under constant tension to a yarn processing point of a textile machine (T) distant from spool (2) or equivalent support from which the yarn (F) unwinds, the tension of said yarn (F) being controlled in proximity to the spool (2) such that this parameter is monitored and controlled immediately after the yarn (F) has been unwound from the spool (2), the yarn (F) fed to the textile machine (T) cooperating, before reaching said processing point on the machine (T), with a series of thread guide elements (8) which modify the tension of the regulated tension. A secondtension control is effected in proximity to the textile machine (T), said control being used for further adjustment of the tension of the yarn (F) in proximity to the spool (2) to hence regulate the tension of the yarn (F) entering the machine (T) to a predetermined constant value.

Description

technical field [0001] The invention relates to a method and a device for feeding yarn with constant tension into a textile machine as described in the preamble of the main claim. Background technique [0002] Yarns used by textile machines for producing articles must preferably be fed into the machine at constant tension or constant speed in order to achieve defect-free production. For this purpose, devices for obtaining at least a constant tension feed are known: these devices utilize a tension sensor cooperating with the yarn and connected to an electronic circuit, usually comprising a microprocessor control unit, in order to provide the yarn tension in real time data. The control unit receives the tensions detected by the sensors and compares them with programmable predetermined tension values ​​(or given values); from this comparison, it ) is carried out, the control unit acts on the controlled element cooperating with the yarn in order to change the yarn tension if n...

AI Technical Summary

Problems solved by technology

[0010] However, this known method for feeding yarn into a textile machine only enables the yarn tension to be monitored and monitored after the yarn has been unwound from the relevant bobbin and close to it, as stated in the preceding case. Control, for obvious spatial reasons or technical / physical reasons related to the operation of the components used for their execution, said devices are forced into close contact with the spool (in the case of "rotary yarn taking") or close to it (in the case of "upper end In the case of taking yarn) operation

[0011] There is therefore no way to ensure a constant and even tension of the individual yarns entering the area of ​​the textile machine that is taken up by the machine elements to produce an article with it

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