The invention relates to a double-folding drafting unit, comprising five pairs of rollers, a first, a second, a fourth and a fifth pair of rollers having essentially an identical orientation of the respective axes of the rollers, and a third pair of rollers, which is positioned between the second and the fourth pair of rollers, having an axial direction which is oriented perpendicularly to the axial direction of the other pairs of rollers, an apron being guided in each case around each roller of the first and third pair of rollers and at least one reversing rail assigned to the respective roller, and an apron being guided around each roller of the fourth pair of rollers and around a reversing rail in front of and a reversing rail behind the respective roller. The invention relates, furthermore, to a spin-knitting machine comprising at least two double-folding drafting units.

The invention relates to a double-folding drafting unit, comprising five pairs of rollers, a first, a second, a fourth and a fifth pair of rollers having essentially an identical orientation of the respective axes of the rollers, and a third pair of rollers, which is positioned between the second and the fourth pair of rollers, having an axial direction which is oriented perpendicularly to the axial direction of the other pairs of rollers, an apron being guided in each case around each roller of the first and third pair of rollers and at least one reversing rail assigned to the respective roller, and an apron being guided around each roller of the fourth pair of rollers and around a reversing rail in front of and a reversing rail behind the respective roller. The invention relates, furthermore, to a spin-knitting machine comprising at least two double-folding drafting units.

The invention discloses a method of dynamically configuring linear density and blending ratio of yarn by two-ingredient asynchronous/synchronous drafted, comprising: a drafting and twisting system, which includes a first stage drafting unit, a successive second stage drafting unit and an integrating and twisting unit. The first stage drafting unit includes a combination of back rollers and a middle roller. The second stage drafting unit includes a front roller and the middle roller. Blending proportion and linear densities of the two ingredients are dynamically adjusted by the first stage asynchronous drafting mechanism, and reference linear density is adjusted by the second stage synchronous drafting mechanism. The invention can not only accurately control linear density change, but also accurately control color change of the yarn. Further, the rotation rate of the middle roller is constant, ensuring a reproducibility of the patterns and colors of the yarn with a changing linear density.

A drawing apparatus for air spinning machines with multiple feeds includes independent introducer elements that feed simultaneously at least two separate slivers of textile fiber. A first drive roller intercepts a first sliver and a second drive roller intercepts the second sliver. The drive rollers may be operated at different speeds of rotation, to perform different degrees of drawing of the two slivers.

A drawing apparatus for air spinning machines with multiple feeds includes independent introducer elements that feed simultaneously at least two separate slivers of textile fiber. A first drive roller intercepts a first sliver and a second drive roller intercepts the second sliver. The drive rollers may be operated at different speeds of rotation, to perform different degrees of drawing of the two slivers.

A drawing apparatus (4) for air spinning machines with multiple feeds, comprising: at least a first and a second introducer element (8,12), independent of each other, so as to be able to feed simultaneously at least two separate slivers (N1, N2) of textile fiber, an air spinning device (16) suitable to spin said slivers (N1, N2) of textile fiber, a drawing device (24) placed. between the introducer elements (8, 12) and the air spinning device (16), comprising a plurality of pairs of drawing rollers (28), comprising one drive roller (32) and one idle roller (36) per pair, said drawing rollers (28) being suitable to perform a progressive drawing of each sliver simultaneously intercepted by them, characterized in that at least one drive roller (32) of a pair of said drawing rollers (28), is mechanically split into a first drive roller (40) which intercepts a first sliver (N1) and a second drive roller (44) which intercepts the second sliver (N2), said first and second drive rollers (40,44) being operatively connected to separate drive means so that they may be operated at different speeds of rotation, to perform different degrees of drawing of the two slivers (N1, N2) intercepted by said first and second drive roller (40,44), wherein said first drive roller (40) is associated with a first idle roller (52) and said second drive roller (44) is associated with a second idle roller (56), said idle rollers (52,56) being mechanically separate from each other.

The invention relates to a device for positioning at least one roller in a drawing device and/or in a spinning unit, and/or for tensioning at least one belt, in particular a running belt, in a drawing device and/or in a spinning unit, wherein the device comprises: the at least one roller which is rotatably mounted, the at least one belt, in particular a running belt, at least one tension rod, and at least one guide device for contacting the belt at at least one contact point for guiding the belt during operation of the at least one roller.

In order to improve and simplify the process of changing the belt, the at least one guide device is arranged and designed in such a way as to make the lower roller reversibly accessible for removing the belt and/or threading the belt, in particular without changing the relative positions of the roller, tension rod and/or belt to one another.