GB980921A - Improvements in or relating to a process and apparatus for plying thin yarns - Google Patents

Abstract

980,921. Plying yarns. E. FEHRER. May 8, 1961 May 17, 1960], No. 16662/61. Headings DID and D1F. In plying two or more yarns by the process in which, in order to offset the loss of singles twist in the plying operation, each yarn is twisted about its longitudinal axis while being fed forward, each yarn is individually untwisted and retwisted in front of the plying print but behind a feed-nip by false-twisting means, and is withdrawn from the false-twisting means at a higher speed than the feeding-speed, so that it is drafted in its untwisted position. The process enables thin yarns of such fibres as coconut to be plied, which fibres lack the strength to be put up in starting yarns of the requisite thickness. As shown, component yarns from packages 1 are fed by a nip 3a of feed-rollers 3 to a collecting-ring 5 and are plied at 8 by a flyer 6 and wound on a braked drum 7, each drum 1 and the corresponding pair of rollers 3 being together mounted on a rotating frame 4. Between nip 3a and ring 5 is provided a false-twisting device which may be a pair of rollers 9 rotating faster than rollers 3, and rotated around the axis of the travelling yarn also faster than rollers 3. The latter rotation of the rollers (a) neutralizes, between the two sets of rollers, the original singles twist and that imparted by the rotation of frame 4 and the former rotation causes the untwisted yarn to be drafted, the distance between the two sets of rollers equalling the average length of the yarn-fibres. This neutralizing twist between rollers 3, 9 is accompanied by the re-insertion of an equal and opposite twist between rollers 9 and ring 5. Rollers 3 may be rotated at a higher speed than that normally necessary to offset the loss of singles twist by an amount necessary to re-insert an equal twist in the thinner yarn produced by the drafting operation. The rollers 3 and 9 may be mounted in a common rotating frame with gearing so that the rollers 3 rotate slower than rollers 9, and the rollers 9 may be replaced by a twist-tube, and a common withdrawing device for the two yarns may be provided to produce the draft. Further, the yarn in packages 1 may have a greater original twist than that required in the component yarns of the final product, the rollers 3 then rotating at the speed at which plying takes place.