| 摘要 |
<p>Device for modulated braking of a weft yarn for textile machines, comprising a set of three yarn guiding eyes (13, 14, 15), which form a straight path for the yarn, and an oscillating lever (24), which is connected to a U-shaped braking element (27) which straddles a central eye (14) of said eyes and engages the yarn (F) in free portions that lie between said central eye and the end eyes (14, 15) of said eyes in order to divert its straight path for braking, characterized in that the oscillating lever (24) is controlled by an electromagnetic actuation means which comprises at least one permanent magnet which is constituted by a cylindrical body (20) having a N-S polar axis arranged radially; the body is associated with a stem (19) which is articulated to the oscillating lever (24) and can move in a linear fashion inside a cylindrical shroud (22) with high magnetic permeance, on which at least one coil (220) is wound, an excitation current (I) flowing through the coil; the axis of the cylindrical shroud (22), which coincides with the axis of the movable stem (19), being perpendicular to the polar axis (N-S) of the cylindrical permanent-magnet body (20). <IMAGE></p> |
