Yarn tension sensor

Device Yarn tension sensor

A yarn tension sensor is disclosed which is adapted for use with a textile yarn processing machine. The sensor includes a spring arm which is contacted by a running yarn, and such that the tension in the yarn acts to deflect the arm. In order to render the deflection of the arm relatively insensitive to external or machine vibrations, while permitting an accurate response to fluctuations in yarn tension, there is provided a structure for damping the spring arm, which includes a magnetic fluid having a portion of the spring arm immersed therein.

The function of yarn tension sensor

In the production and processing of multi-filament yarns, such as the false twist texturing operation, the yarn tension is an important process parameter. Specifically, temporary fluctuations of the yarn tension will have a significant influence on the quality of the yarn, and for this reason, a satisfactory yarn tension sensor must have an adequately high natural frequency so as to be adapted to follow the frequency of the fluctuations of the tension. This requirement presents difficulties, however, since the vibrations of the machine itself may lead to oscillations of the tension sensor.

It is accordingly an object of the present invention to provide a yarn tension sensor which is able to follow the fluctuations of the yarn tension, and which is relatively insensitive to machine vibrations and other external disturbances.

A yarn tension sensor adapted for use with a textile yarn processing machine and comprising, an elongate spring arm having one end adapted to be fixedly mounted to a textile yarn processing machine and an opposite free end which is deflectable in a predetermined deflecting direction with respect to said machine, guide surface means mounted to the free end of said arm for engaging a running yarn, and such that the tension in the running yarn acts to deflect the free end of said spring arm in said deflecting direction, and means for damping the deflecting movement of said free end of said spring arm, said damping means including a receptacle supporting a magnetic fluid, and with said spring arm having a portion thereof immersed in said magnetic fluid.

Fil Control offers 4 types of sensors:

Capacitive sensors

Monitor the tension variations produced by the electrical charges into the yarn in linear motion.

(PA, PE, PES, PP, Spandex …)

Optical sensors

Thanks to infrared beam, optical sensors control the presence of the yarn during linear, to-and-fro or ballooning motion.

Piezo-electric sensors

Monitor a very slow motion or record yarn vibrations of the yarn sliding on ceramic.

Electromechanical sensors

Are used when the presence or absence of the yarn must be controlled at a lower cost.

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