Patent ID: 6224009
Filing Date: 2001-05-01
Classification: B65H,D03D

Abstract:
A device for modulated braking of a weft yarn for textile machines, comprising a set of three yarn guiding eyes, which form a straight path for the yarn, and an oscillating lever, which is connected to a U-shaped braking element which straddles a central eye of said eyes and engages the yarn in free portions that lie between said central eye and the end eyes of said eyes in order to divert its straight path for braking, wherein said oscillating lever is controlled by an electromagnetic actuation means which comprises at least one permanent magnet which is constituted by a cylindrical body having a N-S polar axis arranged radially, said body being associated with a stem which is articulated to said oscillating lever and can move in a linear fashion inside a cylindrical shroud with high magnetic permeance, on which at least one coil is wound, with an excitation current flowing through said coil; the axis of said cylindrical shroud, which coincides with the axis of the movable stem, being perpendicular to the polar axis of said cylindrical permanent-magnet body, said cylindrical shroud being provided in at least two juxtaposed portions, each of which delimits a corresponding stator pole which is separated from the cylindrical permanent-magnet body by a gap, said cylindrical shroud comprising a third cylinder portion which is interposed between said juxtaposed portions and forms a corresponding third stator pole; said movable stem being provided with two cylindrical permanent-magnet bodies which have opposite radial polarities and are fitted and superimposed on the at least one coil being split into two windings which are separated by said third shroud portion and are electrically series-connected.