| 摘要 |
Yarn feeder including a body carrying a drum on which turns of yarn from a spool are wound; a tension sensor for measuring exiting yarn tension value, a braking member including a first permanent magnet and a fixed second magnet, regulator for varying action the second magnet exerts on the first permanent magnet, and a control unit to control the regulator. The first magnet is annular and movable parallel to the axis of the drum and along it between a first position where the first permanent magnet enables pressing the yarn against a counteracting element fixed to the drum and a second position where this effect does not occur. The control unit receives tension values measured by the tension sensor, comparing them with a predetermined value and intervening in real time on the regulator to adjust tension value to predetermined value when these two values do not coincide. |
