| 摘要 |
<p>The device comprises a frustum-shaped braking body (12) that has a continuous circular shape and is supported in front of, and coaxially to, the drum (T) of the feeder (10) in order to engage the thread (F) that runs between the braking body and the drum. The braking body (12) is subjected to the electrodynamic action produced by a modulated energization current (I) that circulates in an energization coil (17) that is rigidly coupled to the braking body and interacts with the field of a permanent magnet. The energization coil (17) is arranged on the frustum-shaped braking body (12) at the region of tangent contact with the drum (T), and the magnetic interaction field is produced by an annular magnet (18) which is substantially toroidal and is arranged so as to face the coil (17) at the outer face or at the inner face of the frustum-shaped braking body (12). <IMAGE></p> |
