Importance

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Abstract

A yarn guide drum of a bobbin winder includes a one-piece metal drum body having a jacket surface. A yarn-guiding reversing thread groove is cut into the jacket surface. The reversing thread groove has intersections and is divided into given groove portions in the vicinity of the intersections and other groove portions. The reversing thread groove has a club-like cross-sectional shape in the other groove portions. The reversing thread groove has a rounded groove bottom, a variable depth at least at the intersections, a variable width, a relatively flatter portion, and a relatively deeper portion interrupting the relatively flatter portion defining a groove portion of relatively lesser depth and relatively lesser width through which the yarn initially passes, being followed by a collector pocket groove portion of relatively greater width which decreases in width as the groove continues. The collector pocket groove portions have lateral reversing thread groove surfaces beginning at the intersections with a concave cross section and a steepness increasing toward the jacket surface and gradually merging with the club-like cross-sectional shape with increasing distance from the intersections.

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First Claim