GB893568A - Method and apparatus for imparting a false hard-twist to yarns - Google Patents

Abstract

893,568. Twist-tubes and driving arrangements therefor. UBBELOHDE, L. Sept. 2, 1959 [Sept. 15, 1958; Sept. 24, 1958; Oct. 14, 1958; Nov. 12, 1958], No. 29995/59. Class 120(2) Yarn is false-twisted, e.g. in a crimping or curling process, by passage between the runs of a moving endless belt or through a twist-tube disposed therebetween and the runs are constrained to conform to at least an arcuate portion of the surface of the yarn or of the outer surface of the tube to ensure intimate frictional contact therewith and thereby impart a rotary movement to the yarn or tube. The belt may be flat or of oval or circular cross-section. As shown in Figs. 1 and 6, yarn bundles or tubes, as at 5, are rolled between the runs 1 and 1a of a belt passing around driven roller 2 and roller 3 (or rollers 3, 27 and 28) and between pairs or trios-of flanged, idler rollers or pulleys 4, 4a, 4b, 4c which cause the runs to converge: pairs of pulleys may be replaced by single pulleys 4, 4c, 4a &c., Fig. 1, disposed alternately on the outside of opposing belt runs. The twist tubes may comprise flat or tapered collars or discs, engageable with the edges of the belt to limit its axial movement in the direction of travel of the yarn; and/or helical threads which cause the belt to deflect the tube from the edges, Figs. 2, 2b (not shown). Each tube 35 may be loosely held at its ends within forked supports, as at 10, Fig. 5, and the ends may be supported by discs 32 or 32 and 32a freely rotatable on pivots 33, 35a. The tube may be supported and its position maintained by a current of air, produced by a flat-cone or disc mounted on the twisting tube, impinging on a separate stationary plate, Fig. 2b (not shown). In other embodiments, Figs. 7-10, 10a-d, 11, 11a (not shown) the two runs of the belt, which are otherwise liable to rub against one another in operation, are spaced further apart by rollers 4, 4a &c. than as described above and are arranged obliquely to the yarn bundles passing therebetween so that in the twisting zone the travelling bundles first touch the one run on entry and the other run on departure.