YARN WINDING APPARATUS BARREL CAM AND METHOD OF MAKING THE CAM GROOVE

摘要

A yarn winding apparatus for winding generally cylindrical cross-wound packages in which the yarn wave in the extremity of each reversal has the smallest possible radius it will retain on the package. The apparatus includes a rotatably driven barrel cam having a generally continuous helical groove in its surface, a traverse guide riding in the groove through which yarn passes at an angle in an uncontrolled length to a point of tangency on a driven cylinder spaced from the guide. The groove has a profile comprising successive helical, reversal curve and helical portions. The reversal curve portion is characterized by being derived from the sum of the first derivative of the yarn reversal plus the product of the uncontrolled yarn length and the second derivative of the yarn reversal curve. The yarn package comprises layers of helical coils wound on a bobbin. The coils are laid down at the mid-portion of their reversals throughout the package in a curve having a minimum radius R according to the expression: R = r/u WHERE R IS THE RADIUS OF THE BOBBIN AND U IS THE COEFFICIENT OF FRICTION OF THE YARN.