EP3408436B1 - Knitted fabric and method and device for producing said knitted fabric - Google Patents

Description

The present invention relates to a method for producing a knitted fabric, in which a sliver in the form of a roving from non-consolidated fiber bundles of a roving warping and consolidation unit, a drafting device with at least two pairs of drawing rollers arranged one after the other in the yarn transport direction and a spinneret device arranged downstream of the drawing device in the yarn transport direction has, fed and is distorted by the at least two pairs of drawing rollers, at least one input roller pair and one output roller pair of the drafting device being driven in a controlled manner in accordance with the pattern of the knitted fabric to be formed on the knitting machine in such a way that the yarn thickness of the drawn roving over its length by changing the relative speed between the input roller pair and the output roller pair is varied, the warped roving emerging from the drafting device is fed to the spinneret device and through this by means of pressure load is solidified, and then the warped, solidified roving is fed directly or via at least one transport or clamping means to the knitting machine.

The present invention further relates to a device for producing a knitted fabric, which has at least one knitting machine, at least one roving warping and consolidation unit arranged upstream of the knitting machine in the yarn transport direction, which has at least one drafting device with at least two pairs of drawing rollers arranged one after the other in the yarn transport direction and at least one of the drawing devices in the Spinning nozzle device arranged downstream of the yarn transport direction, at least one driven roller of an input roller pair and at least one driven roller of an output roller pair of the drafting system being coupled to at least one drive, which is / are coupled to a pattern control for the knitting machine.

In addition, the present invention relates to a knitted fabric which is formed from a warped, consolidated roving with a yarn thickness varying along its length, the yarn thickness of the warped, consolidated roving depending on is formed from the pattern of the knitted fabric.

From the publication DE 10 2011 053 396 A device and a method for producing a knitted fabric is known, in which a knitting machine is directly coupled to a roving warping and consolidation unit, which has a drafting device for warping a roving and a spinneret device for temporary consolidation of the warped roving, the length the yarn consolidation path following the spinneret device is defined by a pair of pinch rollers. As a result, the warped, consolidated roving can be guided directly from the roving warping and consolidation unit over a long distance expedient for industrial applications to the knitting machine. In this way, particularly soft and plump knitwear can advantageously be produced.

Yarns with a varying yarn thickness are also known from the prior art, but mostly the yarn thickness of such so-called nubbed yarns is changed only with regard to the appearance of the knitted fabric made from the yarn. The pimple yarn can have thickenings, so-called pimples, at regular or irregular intervals. Yarns with knobs varying in length and spacing from one another are used in particular to produce knitwear which is intended to give the impression that they have been hand-knitted.

In the publication DE 1 910 034 A. describes a method and a device for producing yarns with randomly varying yarn thickness, in which irregular changes in the yarn thickness of the base yarn are brought about and at the same time the thickness and the length of the knobs produced are varied in an irregular manner. This is indicated in the publication DE 1 910 034 A. described device on a controllable, operating at variable speed drive device. The drive device is operatively connected to a rear set of stretchers to drive it completely independently of a front set of stretchers associated with that set which is spaced from the rear stretchers. The feeding of a strand of a textile material to the stretching zone extending between the sets of stretching devices can thus be regulated completely independently of the speed at which the warped yarn is discharged from the front set of stretching devices. According to the method, a randomly changing signal is generated to generate the thickening of the knobbed yarn, which causes that the working speed of the rear set of stretchers is controlled completely independently of the working speed of the front set of stretchers. Although in the publication DE 1 910 034 A insists that changes in yarn thickness in the yarn produced do not produce a repeating pattern, but it is also noted that there may be certain cases where it is desirable to program the changes in yarn thickness in advance according to a determinable pattern.

That in the publication DE 1 910 034 A. The method described and the device described therein serve exclusively to produce yarn with a varying yarn thickness, which is subsequently further processed to produce a substance, such as a woven fabric.

In the publication WO 2016/091521 A1 a combination of spinning device and knitting machine is used, with the spinning device being able to produce a fiber structure or a yarn of variable thickness from a roving and to be able to feed the stitch forming elements of the knitting machine. For this purpose, at least two roller pairs of a drafting system of the spinning device have their own, independently controllable drive devices by means of which the relative speed between an input and an output roller pair of the drafting system can be changed, or friction spinning devices with at least one feed roller are provided on the machine, the speed of which is in relation is controllable to a pair of discharge rollers. The known device and the known method can be used to produce knitwear with a pattern which is produced by forming stitches with a different fiber bandage or yarn thickness, the pattern being formed by varying the fiber bandage or yarn thickness in the direction of the stitch rows and / or in the direction of the wale .

It is the object of the present invention to provide a method, a device and a knitted fabric with an even greater variability in the formability of patterns with simultaneously optimized use of materials.

The object is achieved on the one hand by a method of the type mentioned at the outset, in which, by controlling the rotational speed of at least one roller of the pair of output rollers of the drafting system, the yarn delivery speed of the warped, solidified roving to the knitting machine depending on the stitch size to be knitted by the knitting machine.

Advantageously, the processing of the warping, hardened roving, which varies in thickness, can optimize the use of material when producing a knitted fabric. In the method according to the invention, the yarn thickness of the warped, hardened roving emerging from the roving warping and strengthening unit is changed according to a pattern knitted by the knitting machine by the roving warping and hardening unit coupled to the knitting machine.

To produce the thickness-varied, warped, solidified roving, a sliver in the form of an unconsolidated fiber bundle is fed to a drafting device of the roving drafting and setting unit, which is drawn by at least two pairs of drawing rollers arranged one behind the other in the yarn transport direction and arranged by a spinning device downstream of the drawing device in the yarn transport direction is solidified. To solidify the roving warped in the drafting device, this is acted upon by compressed air through the spinneret device. The consolidation section can be terminated, for example, by a pair of pinch rollers following in the yarn transport direction of the spinneret device, whereupon the thickly varied, warped, bonded roving can be transported over long distances without any problems directly from the roving warping and consolidation unit to the knitting machine arranged downstream in the yarn transport direction.

To change the yarn thickness of the warped, hardened roving produced in the roving warping and strengthening unit, at least one pair of input rollers, i.e. the first pair of drawing rollers in the direction of yarn transport, and one pair of output rollers, i.e. the last pair of drawing rollers of the drafting device in the direction of yarn transport, correspond to the pattern of the Knitting machine trainees controlled by knitting. The control takes place in such a way that the yarn thickness of the warped roving produced by the drafting device is varied over its length by changing the relative speed between the input roller pair and the output roller pair. The yarn thickness of the warped roving can be varied over its length by changing the relative speed between the input roller pair and the output roller pair.

For this purpose, the rotational speed of the controlled input roller pair is advantageously changed so that more or less sliver is fed to the drafting system depending on the set rotational speed. The speed of rotation of the pair of output rollers can be kept constant, for example. In alternative embodiments, however, the speed of rotation of the pair of output rollers relative to a constant speed of the pair of input rollers can also be varied depending on the pattern to be knitted. Furthermore, both the input and the output roller pair can be driven in a controlled manner such that the yarn thickness of the warped roving emerging from the drafting device can be adapted to the pattern to be knitted via the relative speed between the input and output roller pair. The rotation speed of the controlled input roller pair can be changed according to the pattern.

With an increase in the rotational speed of at least one driven roller of the input roller pair relative to the rotational speed of at least one driven roller of the output roller pair, the yarn thickness of the warped, hardened roving to be produced increases. Conversely, the yarn thickness of the warped, solidified roving to be produced decreases with a reduction in the rotational speed of at least one driven roller of the input roller pair relative to the rotational speed of at least one driven roller of the output roller pair.

Advantageously, in each case only one roller of the pairs of stretching rollers is driven, the respective second roller moving in the opposite direction to the driven roller by pressing against it. In alternative design variants of the invention, however, both rolls of a pair of stretching rolls can also be driven.

Furthermore, in alternative variants of the method according to the invention, the slub fed to the drafting system can also be warped by more than two, for example three or four, pairs of drafting rollers.

It is preferred that spinnerets of the spinneret device contain the warped roving in Twist the yarn transport direction and convey it automatically, the spinneret device advantageously having at least two spinnerets which operate pneumatically and act on the warped roving emerging from the drafting device with compressed air with opposite directions of rotation in each case.

Furthermore, it is also preferred if at least one pinch roller of one of the pair of pinch rollers arranged downstream of the spinning nozzle device in the yarn transport direction is driven, wherein the rotation speed of the at least one pinch roller can also be changed here, depending on the pattern to be knitted, depending on the embodiment variant of the method according to the invention. By passing the warped, hardened roving through the pair of pinch rollers, the hardening distance of the spinneret device can be limited, whereby the warped, hardened roving can be transported with sufficient strength to the respective knitting point.

In addition, in the method according to the invention, by controlling the rotational speed of at least one driven roller of the pair of output rollers of the drafting unit, the yarn delivery speed of the warped, consolidated roving to the knitting machine is set as a function of the stitch size to be knitted by the knitting machine.

The change in the yarn delivery speed is thus made possible in the method according to the invention by adapting the rotation speed of the last pair of drawing rollers of the drafting device in the direction of yarn transport, the rotation speed of the output roller pair having to be set higher for an increasing yarn delivery speed and the rotation speed of which having to be reduced to achieve a falling yarn delivery speed.

Thus, in the method according to the invention, both the yarn count or yarn thickness, ie the mass of the yarn per yarn section, and the yarn delivery quantity are adapted to the stitch size of the knitted fabric to be knitted.

It has proven to be particularly advantageous if only one roller of the pair of output rollers is driven to the knitting machine as a function of the stitch size to be knitted and the amount of yarn required for this is and the associated roller is set in motion by pressing against the driven roller. Furthermore, both rollers of the pair of output rollers can also be driven in a pattern-controlled manner.

By changing the yarn delivery speed, stitches of different sizes can be knitted on the knitting machine, the stitch size to be knitted being made possible by varying the depth of cut on the knitting machine. By knitting stitches of different sizes, transparent and less transparent areas can be created in a knitted fabric.

Furthermore, a proportional change in the relative speed of the input roller pair to the output roller pair and a resultant change in the yarn thickness of the warped, solidified roving used in the knitting machine, and by means of the variation in the yarn delivery speed that can be easily achieved by changing the stitch size, produce knitted fabrics that are approximately constant Have a basis weight and are characterized by an almost homogeneous transparency or opacity.

Leggings and tights known from the prior art are, if they are not assembled from different parts, consistently formed from a knitted fabric with a constant yarn thickness. As a result, the leggings or tights are transparent or translucent, for example due to a greater stretch in the buttocks area. In order to prevent the underwear and / or skin from showing through, the leggings or tights have to be bought accordingly, which in turn has the disadvantage that it slips more easily and, for example, is not tight enough in the calf area.

When manufacturing a circular knitted fabric, the diameter of the knitted fabric is largely defined by the structural conditions, such as cylinder diameter and number of needles. This can only be changed within certain limits by varying the mesh size. Manufacturers exploit this effect with leggings. The knitted fabric diameter increases with increasing stitch size. Thus, a leggings leg can be given a certain shape. However, this shaping is only possible with a predetermined thread size. As a result, in the prior art, the opacity of small meshes and thus of small knitted fabric diameter is higher than that of large meshes and thus large knitted fabric diameter.
In contrast, the method according to the invention makes it possible to adapt the thread size and the mesh size to the knitting pattern to be formed. In a preferred embodiment of the method according to the invention, the drafting system is therefore controlled such that the larger the stitch size to be knitted by the knitting machine, the lower the relative speed between the input roller pair and the output roller pair and the greater the rotational speed of the at least one driven roller of the output roller pair , and the smaller the stitch size to be knitted by the knitting machine, the greater the relative speed between the input roller pair and the output roller pair and the lower the rotational speed of the at least one driven roller of the output roller pair is set. In the case of knitwear such as leggings or tights, an unattractive shining through of underwear and / or skin, for example in the region of the buttocks, as a result of increased stretching in this area can be avoided.

For this purpose, when using the method according to the invention, the stitches can be knitted larger in areas in which the knitted fabric produced is subjected to greater stretching during wear, such as in the area of the buttocks, and on the other hand the yarn thickness can be increased depending on the size of the stitches . Accordingly, the yarn thickness is advantageously adapted as a function of the stitch size to be produced, the yarn thickness of the warped, hardened roving supplied to the knitting point increasing with increasing stitch size and the yarn thickness decreasing with decreasing stitch size. In the method according to the invention, the stitch size and the yarn thickness of the knitted fabric to be formed are thus determined in a pattern-controlled manner.

For this purpose, the relative speed between the input roller pair and the output roller pair is preferably set inversely proportional to the stitch size to be knitted by the knitting machine, and the rotational speed of the at least one driven roller of the output roller pair is set directly proportional to the stitch size.

In order to enable the warped, hardened roving to be knitted particularly easily and to knit a very high quality knitted fabric, it has proven to be Proven particularly favorable if the warped, consolidated roving is fed to the knitting machine with a constant yarn tension. In alternative embodiments of the method according to the invention, the warped, solidified roving cannot be fed to the knitting machine with constant yarn tension, but can be adapted to the knitting pattern, for example.

Furthermore, with regard to the durability of the knitted fabric to be produced, it has also proven to be helpful if at least one auxiliary thread is fed to the drafting system, an auxiliary thread feed speed to the drafting system depending on the stitch size of the knitted fabric to be formed on the knitting machine and / or depending on Elongation properties of the auxiliary thread is controlled. The auxiliary thread feeding speed to the drafting device can also be controlled depending on the pattern of the knitwear to be formed on the knitting machine.

It has proven to be particularly practical if the auxiliary thread is drawn off through the last pair of drawing rollers of the drafting device in the direction of yarn transport, that is to say the pair of output rollers. Since the individual rollers of the drafting system may move at different speeds of rotation, the auxiliary thread fed to the last pair of drafting roller rollers of the drafting system is only exposed to a single rotational speed, so that the feeding of the auxiliary thread is suitably adapted to this rotational speed and thus to the pattern of the knitted fabric to be formed on the knitting machine can. In further variants of the method according to the invention, however, the auxiliary thread can also be fed to the roving at another point, for example before it is fed to the drafting system. Advantageously, a core-sheath yarn is formed by feeding the auxiliary thread to the roving, in which the warped, consolidated roving wraps around the auxiliary thread in bundles.

Depending on the embodiment of the method according to the invention or the knitted fabric to be formed therewith, an inelastic thread, a so-called core thread, or an elastic thread, a so-called elastane thread, can be used as an auxiliary thread. By using the auxiliary thread, the warped, hardened roving to be fed to the knitting machine and containing the auxiliary thread can be made available with increased stability.

Furthermore, the roving can also have more than one auxiliary thread, for example two or three Auxiliary threads are fed. It has proven to be advantageous here if the respective auxiliary threads are fed to the drafting device by separate auxiliary thread feed devices. However, they can also be transported to the roving by means of a single auxiliary thread feed device.

Advantageously, by introducing the at least one auxiliary thread into the roving and the thread thickness or thread thickness adapted to the stitch size to be knitted in each case, a knitted fabric can be produced in which an unsightly shimmering effect due to a large elongation, as explained above, often for example in the case of Leggings or tights in the buttocks area should be avoided. As a result, a knitted fabric can be produced which, particularly when worn, has approximately the same transparency or opacity and a beautiful, uniform overall impression, without undesirable shimmering effects.

In the present invention, the at least one auxiliary thread, such as at least one elastane thread, can be introduced into the roving as a core thread, that is to say as an auxiliary thread covered by fibers of the roving. In the later product, this has clothing physiological advantages for the person wearing it. The elastane then does not lie on the skin as with plating, but is covered by the fiber covering.

In a particularly favorable embodiment variant of the method according to the invention, several warped, consolidated rovings are formed on separate roving warping and consolidation units and fed by these separate knitting systems to the knitting machine, the roving warping and consolidation units being controlled and operated independently of one another. Such an embodiment has proven to be particularly advantageous when used on small circular knitting machines.

In alternative embodiments of the method according to the invention, however, two or more warped, consolidated rovings can also be formed by a common roving warping and consolidation unit and subsequently fed to one or more separate knitting systems of the knitting machine.

It is also possible for several roving warping and consolidation units to be combined into one module and to be electronically controlled together. In this case, either all roving warping and strengthening units or only individual roving warping and strengthening units can be combined into one module. Modular operation of the roving warping and strengthening units has proven to be particularly advantageous with regard to the use in small circular knitting machines.

In advantageous embodiments of the method according to the invention, a knitting system of the knitting machine is supplied with warped, consolidated roving by at least two of the roving warping and consolidation units. As a result, two, three, four or even more than four strands of warped, consolidated roving can be produced separately and brought together at the respective knitting system, that is to say at the respective stitch formation point. This makes it possible to integrate different rovings made of different materials and / or with different yarn properties in the knitted fabric to be formed.

The object of the present invention is further achieved by a device of the type mentioned at the outset, in which the knitting machine has a depth adjustment device which is coupled to the pattern control for the knitting machine and the at least one drive for the at least one driven roller of an output roller pair.

Through the pattern-controlled drive of at least one driven roller of the input roller pair, i.e. the first drawing roller pair in the yarn transport direction, of the drafting system relative to the drive of at least one driven roller of the output roller pair, i.e. the last drawing roller pair of the drafting device in the yarn transport direction, the pre-drawn yarn can be twisted by the device according to the invention be formed with different yarn thickness, the material use of which is optimally adapted to the stitch structure to be formed on the knitting machine.

For this purpose, the knitting machine is coupled to a roving drafting and consolidation unit, which has at least one drafting device with at least two pairs of clamping rollers arranged one after the other in the yarn transport direction, a spinneret device arranged downstream in the yarn transport direction, and advantageously, but not necessarily, the one Consolidation distance of the spinneret device limiting clamping roller pair.

To produce the warped, solidified roving, a sliver in the form of an unconsolidated fiber bundle is fed to the first pinch roller pair of the drafting device in the direction of yarn transport, which is stretched by the individual pairs of drafting rollers and solidified by means of the spinneret device. The warped, consolidated roving can be given additional stability by the pair of pinch rollers arranged below.

In the device according to the invention, at least one roller of each pair of stretching rollers is driven by a drive, both rollers also being able to be driven. A change in yarn thickness is achieved in particular by varying the rotational speed of the input roller pair relative to the output roller pair of the drafting system.

The spinneret device arranged downstream of the drafting device in the yarn transport direction preferably has two self-promoting spinnerets, as a result of which the warped roving is transported by an air flow of the spinnerets directed in the working direction. Advantageously, the two spinnerets are arranged one after the other in the yarn conveying direction, these working pneumatically and having an opposite three-phase current.

The pinch roller pair advantageously arranged downstream of the spinning nozzle device in the yarn transport direction can also be coupled or can be coupled to a drive by means of which at least one pinch roller of the pinch roller pair is driven. By passing the warped, hardened roving through the pair of pinch rollers, the warped, hardened roving is given additional stability and strength, as a result of which the warped roving which is clamped after the spinning nozzle hardening can also be transported to the knitting machine over a relatively long distance without any problems the roving, which is only temporarily solidified, dissolves during this transport. In particular, this type of coupling of the spinning device and the knitting machine enables particularly soft knitted fabrics to be produced very efficiently, in a space-saving manner and comparatively inexpensively.

In a particularly preferred embodiment variant of the device according to the invention, the knitting machine has a cut depth adjustment device which is coupled to the pattern control for the knitting machine.

The stitch size to be knitted can advantageously be varied by the depth adjustment device. The coupling of the depth adjustment device with the pattern control of the knitting machine makes it possible to change the stitch size depending on a pattern to be knitted. Depending on the stitch size to be produced, a stitch-forming needle is driven further or less far by means of the depth adjustment device.

In combination with an adjustment of the yarn thickness in particular, knitwear such as leggings or tights can be produced which have almost the same transparency or opacity even when worn. In this way, ugly shine through of the skin and / or underwear due to increased stretching of the knitwear, for example in the buttocks area of a wearer, can be avoided, among other things. For this purpose, the stitches are expediently made larger in areas in which the knitted fabrics are exposed to higher strains, for example in the buttocks area of a wearer, at the same time increasing the yarn thickness of the knitted fabric. In order to form a particularly transparent knitwear, however, the yarn thickness can also be reduced with increasing stitch size. The adjustment of the yarn thickness can also be done according to the pattern.

In a favorable embodiment of the device according to the invention, the device has a measuring device for determining a yarn tension of a warped, consolidated roving emerging from the roving warping and setting unit. The measuring device can ensure that the warped, hardened roving is fed to the respective knitting point of the knitting machine with constant yarn tension, whereby the warped, hardened roving can be processed in a particularly suitable manner and, at the same time, a knitted fabric of high quality can be produced.

The measuring device can also be used to determine a yarn transport speed or another process parameter. Advantageously, based on regulates the values of the spinning and / or knitting process determined by the measuring device, it being possible to set one or more process parameters, such as the rotational speed of one or more pairs of stretching rollers.

In a preferred embodiment variant of the device according to the invention, the device has at least one auxiliary thread feed device which is connected to the drafting device and can be controlled by the pattern control for the knitting machine and / or depending on the stretching properties of an auxiliary thread to be fed to the drafting device. By inserting an auxiliary thread into the warped, consolidated roving, this is given additional strength and stability. Elongation properties of the warped, consolidated roving can also be influenced by the auxiliary thread, for example.

The auxiliary thread feed device preferably has a take-off which is realized by the pair of output rollers, that is to say the last pair of draw rollers in the direction of yarn transport, of the draw frame, as a result of which the auxiliary thread can be picked up by the last pair of draw rollers and integrated into the warped yarn. By feeding the auxiliary thread only during the main draft, the auxiliary thread only passes through one clamping point of the drafting system. The speed of the auxiliary thread feeding device can be optimally adapted to the rotational speed of the last pair of drafting rollers and / or the pattern control of the knitting machine. Furthermore, the auxiliary thread feeding device can also be controlled as a function of the stretching properties of the auxiliary thread.

Depending on the application, the auxiliary thread can be elastic or inelastic. By feeding an auxiliary thread to the warped, consolidated roving, a core-sheath yarn is preferably created, in which the core is formed by the auxiliary thread. In alternative embodiments of the devices according to the invention, more than one auxiliary thread, for example two or three auxiliary threads, can also be fed to the warped, consolidated roving.

Advantageously, the configuration of the warped, consolidated roving as a core-sheath yarn prevents an unsightly shimmering effect of the knitted fabric, such as leggings or tights, when the knitted fabric is stretched. Furthermore, a shimmering effect can also be caused by the Enlargement of the stitches in combination with the enlargement of the yarn thickness in areas of great elongation can be avoided.

In addition, it has also proven to be particularly advantageous if knitting systems of the knitting machine are each assigned at least two separate roving warping and strengthening units which are independent of one another in terms of control technology. Such an embodiment has proven to be particularly advantageous with regard to use in a small circular knitting machine.

In alternative embodiments of the device according to the invention, however, several of the roving warping and strengthening units can also be combined to form a module and coupled in terms of control technology. Such an application is particularly advantageous with regard to the use in large circular knitting machines. Depending on the application, all or only individual roving warping and strengthening units can be coupled in terms of control technology.

The object of the present invention is also achieved by a knitted fabric of the type mentioned at the outset, in which the yarn thickness of the warped, solidified roving is formed as a function of the respective stitch size of the knitted fabric, the yarn thickness increasing with increasing stitch size and the yarn thickness with decreasing stitch size decreases.

Thanks to the pattern-controlled variation of the yarn thickness, the material used can be optimally adapted to the stitch structure of the knitwear. In addition, in the knitted fabric according to the invention, the yarn thickness of the warped, solidified roving used for its production is designed as a function of the respective stitch size of the knitted fabric, the yarn thickness increasing with increasing stitch size and the yarn thickness decreasing with decreasing stitch size.

The knitted fabric is very particularly preferably a seamless, circular-knitted knitted fabric with a changing diameter and nevertheless a constant opacity. For example, the knitted fabric can be a stocking, the diameter of which increases in the calf area from bottom to top, as a result of which the stitch size in this calf area increases from bottom to top and nevertheless the opacity remains the same, since according to the invention when knitting this calf area from bottom to top, that is with larger stitches, both more and thicker yarn is fed to the knitting point. The same applies vice versa when knitting this calf area from top to bottom, where with smaller stitches both less and thinner yarn is fed to the knitting point. The knitted fabric according to the invention is designed such that it has the same transparency or opacity even when stretched or worn. In alternative embodiments of the knitted fabric according to the invention, however, the yarn thickness can also decrease with increasing stitch size, so that particularly transparent as well as particularly opaque areas can be produced.

The knitted fabric can be a knitted fabric having a pattern.

Figur 1

schematisch einen Abschnitt eines bei einer Ausführungsform des erfindungsgemäßen Verfahrens als Zwischenprodukt ausbildbaren verzogenen Vorgarnes mit unterschiedlicher Garndicke in einer Seitenansicht zeigt;

Figur 2

schematisch eine mögliche Ausführungsform einer erfindungsgemäßen Vorrichtung in einer geschnittenen Seitenansicht zeigt; und

Figur 3

schematisch eine weitere mögliche Ausführungsform einer erfindungsgemäßen Vorrichtung in einer geschnittenen Seitenansicht zeigt.

Preferred embodiments of the present invention, their structure, function and advantages are explained in more detail below with reference to figures, wherein

Figure 1

schematically shows a side view of a portion of a warped roving which can be formed as an intermediate product in an embodiment of the method according to the invention, with different yarn thickness;

Figure 2

schematically shows a possible embodiment of a device according to the invention in a sectional side view; and

Figure 3

schematically shows a further possible embodiment of a device according to the invention in a sectional side view.

Figure 1 schematically shows a section of a warped roving 4b that can be produced as an intermediate product of an embodiment of the method according to the invention in a side view, the roving 4b having a length I in the example shown.

The in Figure 1 The roving section of the roving 4b shown has three areas 41, 41 ', 42, which are distinguished by different yarn thicknesses d, d'. As in Figure 1 shown, the roving 4b in the area 42 has a greater yarn thickness than in the areas 41, 41 '. Here, yarn thickness d, d'einem is on a knitting machine, to which the roving 4b is fed in a temporarily solidified form as a warped, solidifying roving is adapted to knitting patterns. The yarn thickness d, d'als also the pattern of the length in which the roving 4b has a larger or smaller diameter. Here, the roving 4b, unlike in Figure 1 depicted, also have a constant yarn thickness d, d over a long distance. The yarn thickness d, d'can also vary in very short intervals. The areas 41, 41 ', 42, in which the yarn thickness d, d changes, can recur regularly or be irregularly patterned.

The warped roving 4b consists of individual fibers 40 which surround an auxiliary thread that is not visible here. Depending on the application, the auxiliary thread can be elastic or inelastic. Likewise, a warped roving can also be formed which has no auxiliary thread or which has more than one auxiliary thread.

Figure 2 shows schematically an embodiment of an embodiment of a device 1 according to the invention in a sectional side view, the same reference numerals as in Figure 1 Describe the same component and reference is made to the previous descriptions in this regard.

In the Figure 2 The device 1 shown has a knitting machine 2 and a roving warping and strengthening unit 10 coupled to the knitting machine 2.

The roving warping and strengthening unit 10 has a drafting device 5, a spinneret device 6 arranged downstream of the drafting device 5 in a yarn transport direction A and, in the exemplary embodiment shown, a pinch roller pair 7 following the spinneret device 6 in the yarn transport direction A.

In the in Figure 2 In the embodiment shown, the drafting device 5 has three pairs of drawing rollers 51, 52, 53 arranged one after the other in the yarn transport direction A and spaced apart 561, 562. In alternative embodiments, however, the device 1 can also have only two pairs of stretching rollers 51, 53 or more than three pairs of stretching rollers 51, 52, 53. The stretching roller pairs 51, 52, 53 in turn are each formed by two rollers 511, 512, 521, 522, 531, 532.

To produce a warped, consolidated roving 4d, the first drawing roller pair 51 in the yarn transport direction A, the input roller pair, of the drafting device 5 a fuse 4a in the form of an unconsolidated fiber bundle is fed. The fuse 4a is provided in the exemplary embodiment shown by a roving supply unit 3, which has a flyer spool 31, and is guided to the pair of input rollers 51.

In the drafting system 5, the sliver 4a is stretched by means of the pairs of drafting rollers 51, 52, 53. For this purpose, a roller 511, 521, 531 of the respective pair of stretching rollers 51, 52, 53 is coupled to a drive 8, 8 ', 8 "which drives the respective roller 511, 521, 531.

As in Figure 2 2, the non-driven rollers 512, 522, 532 of the respective pair of drafting rollers 51, 52, 53 are printed against the driven rollers 511, 521, 531 with the aid of a drafting pressure arm 54 using springs 541. Here, the rollers 512, 522, 532 are mounted in such a way that they can rotate in the opposite direction to the rollers 511, 521, 531.

In order to produce a warped roving 4b with a yarn thickness d, d 'adapted to the respective stitch size, the drives 8, 8', 8 "are coupled to a pattern control 9, in particular the rotational speed x _{1 of} the drive 8 of the roller 511 of the input roller pair 51 relative to the rotation speed x _{3 of} the output roller pair 53 is regulated in dependence on a pattern to be knitted by the knitting machine 2, by changing the rotation speed x _{1 of} the input roller pair 51 in the example shown, the rotation speed x _{2 of} the stretching roller pair 52 being that of the stretching roller pair 51 beforehand Defined or adjustable transmission ratio follows, and the rotational speed x _{3 of} the stretching roller pair 53 is kept constant.

In order to also be able to influence the stitch size to be knitted, the pattern controller 9 is also coupled to a schematically illustrated depth adjustment device 91 of the knitting machine 2. Here, the process is advantageously regulated in such a way that the yarn thickness d increases with increasing stitch size and the yarn thickness d decreases with decreasing stitches, so that knitwear such as leggings or tights can be produced, which, even when worn, has an almost constant transparency or Have opacity, which an ugly show through in places, which may be stretched more than others, can be avoided. Likewise, the process in alternative variants can also be regulated in such a way that the yarn thickness d, d'decreases with increasing stitch size and vice versa. Accordingly, particularly transparent areas can be formed in the knitted fabric.

The warped roving 4b emerging from the drafting device 5 subsequently enters a spinneret device 6. The warped roving 4b is rotated in the spinneret device 6 by means of air jets. The spinneret device 6 consists of two spinnerets 61, 62 arranged one after the other, which are air swirling nozzles. The air flows generated by the two spinnerets 61, 62 have opposite directions of rotation B, C, so that a false wire is formed.

In the exemplary embodiment shown, the spinning nozzle device 6 is subsequently provided in the yarn transport direction A with a pair of pinch rollers 7 which has two pinch rollers 71, 72 which can be rotated in opposite directions. The distorted, solidified roving 4c emerging from the spinneret device 6 is carried out by the clamping rollers 71, 72 pressed against one another, so that on the one hand a feedthrough and on the other hand a nip point for the roving 4c is formed. Here, the clamping point limits the fiber consolidation distance after the spinneret device 6. The warped, consolidated roving 4d emerges from the pair of clamping rollers and is subsequently fed directly to the knitting machine 2.

In the in Figure 3 The illustrated embodiment of the device 1 'according to the invention is fed to the roving 4b with the aid of an auxiliary thread feed device 220, an inelastic auxiliary thread 22 which serves to increase the strength of the warped, consolidated roving 4d. In this case, the inelastic auxiliary thread 22 is drawn off from a bobbin 24 with an auxiliary thread pinch roller pair 23, in the exemplary embodiment shown it is fed to the drafting device 5 via a thread guide tube 26 and integrated into the roving 4b. In the example shown, the inelastic auxiliary thread 22 is fed to the last pair of draw rollers in the yarn transport direction A, i.e. the output roller pair 53 of the drafting unit 5, so that the thread feed speed v _{4 of} the auxiliary thread 22 only has to be adapted to the rotational speed x _{3 of} the output roller pair 53.

The thread tension of the inelastic auxiliary thread 22 can be checked by means of a thread tension measuring device 43 provided between the auxiliary thread clamping roller pair 23 and the drafting device 5. In particular with regard to the quality of the knitwear produced and the execution of the knitting process, it has proven to be advantageous if the device 1, 1 'has the thread tension measuring device 43 for determining a thread tension of a roving 4d emerging from the pair of auxiliary nip rollers 23d, so that the roving 4d continuous yarn tension of the knitting machine 2 can be supplied.

In addition, in the embodiment of Figure 3 an elastic auxiliary thread 25, for example an elastane thread, is fed to the roving 4b by means of a further auxiliary thread feed device 210. This elastic auxiliary thread 25 is passed through a peripheral drive with the possibility of setting an exact auxiliary thread tension via a thread tension measuring device 42 and then fed to the pair of drawing rollers 53. In the exemplary embodiment shown, the elastic auxiliary thread 25 is fed together with the inelastic auxiliary thread 22 at a thread feed speed v ₅ to the drafting device ₅ via the thread guide tube 26.

It is also advantageous if the auxiliary thread feed device 220, 210 is controlled on the basis of the pattern control and / or the elongation properties of the auxiliary thread 22, 25. In particular, if the auxiliary thread feed device 220, 210 is coupled to the pattern control, the auxiliary thread 23, 25 can be used in accordance with the pattern. Depending on the application, it can be selected whether an elastic auxiliary thread 25 or an inelastic auxiliary thread 22 is used. It is also possible to decide, depending on the application, whether only one auxiliary thread 22 or 25 or possibly a plurality of auxiliary threads 22, 25 are fed to the roving 4b. If several auxiliary threads 22, 25 are used, they should, as in Figure 3 shown, in view of the possibly different auxiliary thread tensions by means of separate auxiliary thread feeders 220, 210 are fed to the drafting device 5. In alternative design variants, however, a plurality of auxiliary threads can also be fed by means of a single auxiliary thread feed device.

The device 1, 1 'according to the invention can advantageously be used to simply produce knitwear with stitches of different sizes, so that with regard to the yarn thickness d, d' which is variable as a function of the stitch size. very transparent or opaque knitwear can be provided. To change the stitch size, the yarn delivery speed is varied from the roving drafting and consolidation unit to the knitting machine, which is realized by changing the rotational speed of the last pair of draw rollers, that is, the output roller pair 53, in the yarn transport direction A.

In the present invention, it is also possible to create different compression zones in a knitted tube by changing the mesh size.

Furthermore, in the present invention, by changing the yarn thickness or yarn thickness, a knitted fabric with different technical properties can be produced. When the yarn thickness is changed, the fiber content in the finished thread is changed in the method according to the invention. The thread count is determined during the process. In this way, for example, conductive auxiliary threads can be sheathed with different numbers of fibers, which in part produces different properties in the knitted fabric that is produced.

With the present invention, it is possible to influence the abrasion resistance of a knitted fabric by adjusting the stitch size and the thread size. In addition, the present invention can be used to influence the performance properties of a knitwear, such as its moisture transport properties and / or heat retention. In addition, the present invention can also or alternatively influence the thermal conductivity and / or the thermal insulation properties of knitwear.

Claims (15)

1. Method for producing a knitted fabric comprising a pattern, in which a sliver in form of a roving (4a) of fiber bundles that have not been strengthened is supplied to a roving drawing and strengthening unit (10), which comprises a stretching unit (5) with at least two stretching roller pairs (51, 52, 53) being successively arranged in thread transport direction (A) and a spinning nozzle device (6) being arranged downstream of the stretching unit (5) in the thread transport direction (A) and is drawn by the at least two stretching roller pairs (51, 52, 53), wherein at least one inlet roller pair (51) and one outlet roller pair (53) of the stretching unit (5) are controllably driven according to the pattern of the knitted fabric to be formed on the knitting machine (2) in such a way that the thread thickness (d, d') of the drawn roving (4b) is varied throughout its length by changing the relative speed between the inlet roller pair (51) and the outlet roller pair (53),
   the drawn roving (4b) exiting the stretching unit (5) is supplied to the spinning nozzle device (6) and is strengthened by it by means of applying compressed air, and thereupon
   the drawn, strengthened roving (4d) is supplied to the knitting machine (2) directly or by using a means for transport or clamping,
   characterized in that
   by controlling the rotation speed of at least one driven roller of the outlet roller pair (53) of the stretching unit (5), the thread supply speed (v₃) of the drawn, strengthened roving (4d) to the knitting machine (2) is set depending on the loop size to be knit by the knitting machine (2).
2. Method according to claim 1, characterized in that the bigger the loop size to be knit by the knitting machine (2), the smaller the relative speed between the inlet roller pair (51) and the outlet roller pair (53) and the bigger the rotation speed of the at least one driven roller of the outlet roller pair (53) is set, and the smaller the loop size to be knit by the knitting machine (2), the bigger the relative speed between the inlet roller pair (51) and the outlet roller pair (53) and the smaller the rotation speed of the at least one driven roller of the outlet roller pair (53) is set.
3. Method according to claim 1 or 2, characterized in that the relative speed between the inlet roller pair (51) and the outlet roller pair (53) is set inversely proportional to the loop size to be knit by the knitting machine (2) and the rotation speed of the at least one driven roller of the outlet roller pair (53) is set directly proportional to the loop size.
4. Method according to at least one of the preceding claims, characterized in that the drawn, strengthened roving (4d) is supplied to the knitting machine (2) with constant thread tension.
5. Method according to at least one of the preceding claims, characterized in that at least one auxiliary thread (22, 25) is supplied to the stretching unit (5), wherein an auxiliary thread supply speed to the stretching unit (5) is controlled depending on the loop size of the knitted fabric to be formed on the knitting machine (2) and/or depending on the stretch characteristics of the auxiliary thread (22, 25).
6. Method according to at least one of the preceding claims, characterized in that several drawn, strengthened rovings (4d) are formed on separate roving drawing and strengthening units (10) and are supplied to separate knitting systems of the knitting machine (2) by them, wherein the roving drawing and strengthening units (10) are controlled and operated independently of each other.
7. Method according to at least one of the claims 1 to 5, characterized in that several roving drawing and strengthening units (10) are combined to one module and are jointly electronically controlled.
8. Method according to claim 6 or 7, characterized in that one knitting system of the knitting machine (2) each is supplied with drawn, strengthened roving (4d) by at least two of the roving drawing and strengthening units (10).
9. Device (1, 1') for producing a knitted fabric which comprises at least one knitting machine (2), at least one roving drawing and strengthening unit (10) being provided upstream of the knitting machine (2) in a thread transport direction (A), which comprises at least one stretching unit (5) with at least two stretching roller pairs (51, 52, 53) being successively arranged in the thread transport direction (A) and at least one spinning nozzle device (6) being provided downstream of the stretching unit (5) in the thread transport direction (A), wherein at least one driven roller of an inlet roller pair (51) and at least one driven roller of an outlet roller pair (53) of the stretching unit (5) are coupled with at least one drive (8, 8', 8"), which is/are coupled with a pattern control (9) for the knitting machine (2),
   characterized in that
   the knitting machine (2) comprises a sinking depth adjustment device (91) which is coupled with the pattern control (9) for the knitting machine (2) and the at least one drive (8") for the at least one driven roller of an outlet roller pair (53).
10. Device according to claim 9, characterized in that the device (1, 1') comprises at least one thread tension measuring device (41) for determining a thread tension of a drawn, strengthened roving (4d) exiting the roving drawing and strengthening unit (10).
11. Device according to claim 9 or 10, characterized in that the device (1, 1') comprises at least one auxiliary thread supply device (220, 210) being connected to the stretching unit (5) and controllable by the pattern control (9) for the knitting machine (2) and/or depending on the stretch characteristics of an auxiliary thread (22, 25) to be supplied to the stretching unit (5).
12. Device according to at least one of the claims 9 to 11, characterized in that knitting systems of the knitting machine (2) are assigned at least two separate roving drawing and strengthening units (10) each, which are independent from each other in terms of control.
13. Device according to at least one of the claims 9 to 12, characterized in that several of the roving drawing and strengthening units (10) are combined into one module and are coupled in terms of control.
14. Knitted fabric which is formed from a drawn, strengthened roving (4d) with a thread thickness varying throughout its length, characterized in that the thread thickness (d, d') of the drawn, strengthened roving (4d) is formed depending on the respective loop size of the knitted fabric, wherein the thread thickness (d') increases with increasing loop size and the thread thickness (d) decreases with decreasing loop size.
15. Knitted fabric according to claim 14, characterized in that the knitted fabric is a seamless, circularly-knitted knitted fabric with varying diameter and yet constant opaqueness

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