DE29518866U1 - Device for producing a spun yarn effect, in particular in the case of yarn blown with air blast - Google Patents

Description

HLLuga92/DE-GM

23.11.95

Device for generating

a spun yarn effect especially

for air-blown textured yarn

The invention relates to a device for producing a spun yarn effect in yarn, in particular in air-blast textured yarn, which has a core and an outer loop structure.

After production, the filament yarn or continuous filament yarn differs greatly from spun yarn made from staple fibers, especially from natural fibers such as wool or cotton. A fabric made from unrefined filament yarn is smooth and is perceived as cold. Since the 1950s, attempts have therefore been made to refine the filament yarn. A well-known process for this is air-blast texturing. The smooth filament yarn is passed through an air-blast texturing nozzle and a loop yarn is produced. Such a process or an air-blast texturing nozzle is shown in EP-PS No. 88 254. Depending on the type of texturing process and the quality of the untreated smooth yarn or the starting material, a variety of yarn qualities can be produced. For example, many smaller loops can be formed over a compact core. This produces a fabric with high slip resistance and anti-slip effect. Well-known applications for such a yarn are ski clothing and backpack fabrics. However, it is also possible to produce a so-called volume yarn. Here, the starting material is a standing yarn and an effect yarn; a compact core and many large loops are produced. The volume yarn provides good coverage in the surface structure of the textile fabric. Good resistance to pilling and high abrasion resistance make this yarn particularly suitable for

I · · I

Quality suitable for the production of car seat upholstery fabrics. A third texturing quality is the so-called soft yarn with a loose loop structure. The yarn is soft and has no compact core. Any larger loops are drawn out through a stretching process.

Despite the great variety of yarn qualities, it is often not possible to obtain a group of very specific quality characteristics on the same product. In certain applications of air-blown textured yarns, for example, the burr effect caused by the loops is a problem. Sometimes you want the fabric to have a soft feel, without the properties of soft yarns. In many applications, the crackling sound, which is also caused at least in part by the loop structure, is a problem. The conflicting objectives are that in many cases you want the effect of the air-blown texturing process, namely the loop structure, without the disadvantages of the loops. For many applications, the advantages of the spinning effect are therefore sought, which include the fact that many of the ends of the staple fibers protrude freely from the yarn, which are advantageous for the feel, the warming effect and the covering capacity, for example.

GB publication no. 633 115 proposes breaking individual filaments in a yarn by frictional contact with an abrasive surface and creating "nubs" or "curls" by moving the abrasive surfaces back and forth. It is not known whether this solution has been used in practice.

A more recent proposal is described in DE-PS No. 32 10 784. It is proposed that the textured yarn provided with loops, bows and the like is guided over one or more rotating rollers mounted one behind the other in the yarn path in at least one winding in such a way that the yarn strand fed to the rollers covers the yarn strand running off the rollers at least in its edge area and in the process

clamps and opens loops, bows, bows and the like of the running thread strand protruding from the thread core on the roll. Rolls can also be used which have a rough surface on the outer edge. In another design as shown in DE-PS No. 35 35 085, attempts are made to vacuum the separated filament pieces in a lint trap. In practice, this solution is still found here and there. Contrary to expectations, however, the desired uniform effect is often not achieved or at least not satisfactorily. Both solutions have the major disadvantage that the tearing of the loops cannot be technically controlled. The intensity of the loop opening can be influenced by tighter guidance and, if necessary, special design of the abrasive surfaces. However, it is not possible to control the tearing points at all, for example. It is difficult to process a single yarn using tools with state-of-the-art solutions. However, for the large number of yarn qualities with any linear density, only a few of which have been described in the introduction, there are far too few options for achieving a reproducible effect with a controlled mechanical intervention.

The invention was now given the task of treating air-blast-textured yarn in particular in such a way that, on the one hand, the advantages of the texturing process are retained as far as possible, but on the other hand, a spun yarn effect is achieved or at least achieved or retained to a high degree. In particular, however, a desired spun yarn effect should be gradually adjustable.

The device according to the invention is characterized in that it has a processing point formed by a processing support and a preferably motor-driven grinding or cutting tool as well as micro-adjustment means for adjusting the processing depth.

The inventors have recognized that the state of the art relied too heavily on a theoretical model of yarn processing. As a spun yarn has protruding

This was the aim. However, mechanically "working all around" a yarn is very difficult, especially when it comes to opening a huge number of individual protruding parts or loops. Attempts were made to do this by hand, by rubbing and pulling on the entire surface. The aim of opening part of the loops in textured yarns could indeed be achieved, but with an uncontrollable method. Even good settings once found for a particular yarn cannot be transferred to another yarn in any way. In complete contrast to this, the new invention proposes reducing the yarn from one side to a certain thickness. Two facts allow one-sided reduction in relation to textured yarns. Firstly, the loops of a textured yarn are very rarely aligned only in the lengthwise direction of the yarn. Most of the time they have a helical component. This means that when a loop is cut open, the two filament ends protrude at different points around the circumference. The yarn is processed to produce a fabric with the familiar twisted course, so that the threads lie next to each other in constant alternation. Sometimes two threads lie on top of each other, one side of the thread is on the inside of the fabric or on the outside of the fabric, etc. The result of this is that the same applies to the freely protruding filament ends produced according to the invention. The effect of the newly formed protruding ends is primarily a statistical one. Regardless of where the filament ends originally protrude, in the fabric these ends have the same effect as the protruding ends of staple fibers in spun yarn. The really surprising thing, however, is that in terms of reproducibility for processing yarns, the new invention is in no way inferior to the technology of industrial grinding or, for example, milling technology:

- the throughput speed of the yarn is given;

- the processing speed of the tool is independent
the speed at which the yarn passes through can be determined;

- the yarn is stretched onto a defined base, namely the processing support;

- the distance of the machining tool to the machining support
can be numerically adjusted with the highest precision.

The only task that remains is to determine the optimal setting values for each particular yarn quality so that the identical result can always be achieved with any repetition.

The new invention allows a whole number of very advantageous designs. Preferably, the tensile force in the yarn is kept constant in the area of the processing support. The processing can be carried out "off-line" in relation to texturing. Yarn that is already wound on spools can thus be processed as required. This has the great advantage that a stronger or weaker spinning effect can also be generated at the yarn doffer to suit the specific requirements, e.g. as part of a simple rewinding process. However, the yarn can also be processed continuously directly after texturing at the processing speed from texturing, whereby the tension in the yarn is kept constant after processing and preferably regulated in a reproducible manner. It is also possible to process two threads or even several at the same time according to the invention, e.g. corresponding to two positions during texturing or a number during rewinding corresponding to the winding position.

The depth adjustment is carried out in microsteps, whereby a sub-step is preferably 10 μ or less. A step division of 5 μ is very practical, for example. However, step divisions of 20 μ or more are also conceivable. However, since high reproducibility is desired, a value as small as possible of 5 μ or 10 μ is preferred. It is also possible for the same yarn to be processed two or more times, preferably with the same grinding or cutting tool. Even with repeated processing, there is no risk of the core or the post being damaged during the second or third processing, since the processing distance is set precisely and the

Tools cannot penetrate the core at all, except for fine adjustment.

The relative speed of the grinding or cutting tool compared to the continuously running yarn should be high, but at least 20% to 50% higher. Preferably, the relative speed corresponds to the practice of the well-known plastic or woodworking tools. The tool engagement is not only active but, as with all corresponding industrial processing in the sense of a numerically controlled machine tool, is necessarily guided. Tests have confirmed the correctness of this statement by showing that, for example, when using a grinding tool, grinding dust is generated in addition to individual fluff. The tests have also confirmed that the grinding or cutting tool can move in the same direction or in the opposite direction to the yarn. Depending on the type of tool, the rotation speed of the tool must be adjusted accordingly. In principle, the opposite direction allows a lower tool speed. However, it is also possible, especially when a grinding tool is used, to decide on a same direction or in the opposite direction depending on the yarn quality. Although processing transverse to the direction of yarn travel is also possible, in the majority of applications, parallel or counter-rotation will be more advantageous. The processing waste is sucked out of the zone immediately after the processing point, with an air flow preferably being generated transverse to the direction of yarn travel by the suction.

Another important point is that a thread guide is arranged at a distance before and after the processing point, such that the thread is guided against the preferably convex grinding support in the operating state. This measure not only allows good thread guidance over the processing support but also brings the thread into an optimal position for the tool to engage. By pulling it slightly around a corner, a larger number of protruding parts or loops have a tendency to protrude even more, so that the

The effect of the tools is better. The tool is designed, for example, as a high-speed grinding wheel, preferably with a diamond coating, or as a knife mechanism, with the processing width being a multiple of the yarn diameter. It is also very advantageous if a traversing device is arranged on the thread inlet side for the constant lateral displacement of the processing point. The device preferably has numerical setting means with a micro-adjustment for the processing depth and a release for an open threading position. In terms of function, it makes no difference whether the tool is adjusted towards the processing support or the processing support towards the tool. However, the setting means and the release are expediently assigned to the correspondingly adjustable processing support, with the release preferably having two position ranges, a fully open locking point and an intermediate position, which automatically moves the processing support into the working position via a spring tension and holds it in an exact working position. The spring tension has a second function, in that it serves as a safety element in case a foreign body gets between the processing support and the processing tool. The same applies if the yarn winds up on the tool due to a breakdown. Furthermore, the spring eliminates any play in the adjustment means. For practical operation, it is almost essential that the adjustment means have a numerical position indicator for the processing depth, whereby the position indicator value is a relative reference value that can be used for identical reproducibility of the processing depth, especially for the same yarn quality. Otherwise, the new setting would have to be sought after every product change. With the proposed measure, the numerical setting value can be taken from the data sheet for the machine setting for a particular yarn quality and used again at any time with the same precision. According to a further design idea, the grinding or cutting tools and the processing support are arranged in a closed housing. The housing has a suction opening in the area after the processing point, for

* ■

Extraction of the processing waste. The housing preferably has at least one further opening opposite the extraction opening, for generating a cross-flow to the yarn in the area after the processing point. The housing can also be designed as a housing block which has the thread guides, the processing support with the adjustment means, the grinding or cutting tool and a traversing device. The processing support is preferably made as a stationary body, preferably from highly wear-resistant material such as ceramic. However, tests have shown that the processing support can also be designed to be movable and for example, driven by the yarn itself. According to a further proposal, the processing support has a rounded support surface, with the thread guides being arranged in relation to the support surface in such a way that an angle of less than 180°, preferably of about 150° to 175°, is formed between the thread inlet and the thread outlet.

The invention will now be explained using some embodiments
explained in more detail. They show

Figure 1 shows the new invention with the main elements;

the figure IA, IB, IC, ID various sections across a

Filament before, during and after processing;

Figure 2 shows a simplified section through a device;
Figure 3 is partly section and partly view of Figure 2 according to

the section line III - III;
Figure 4 is a side view IV of Figure 3 with a linear

moving oscillation;

Figure 5, 5a shows the micro-adjustment means on a larger scale;
Figure 6 shows a configuration in which two threads

can be processed according to the invention;
Figure 7 shows a section along line VII - VII of the

Figure 6;
Figure 8 shows a section VIII of Figure 6.

In the following, reference is now made to Figure 1, as well as IA, IB, IC and ID. The starting material here is a textured yarn la, with the known loops 2 as in Figure IA

·

is shown graphically on a larger scale. The textured yarn is assumed to be known. The loops 2 form a rather fluffy sheath and enclose the core formed from a large number of so-called uprights 3, which are shown with small circles. The upright filaments together form the thread core 4. The transition from the thread core 4 to the loops 2 of the sheath is not sharp, however, but rather fluid. Because the yarn is shortened during texturing, the uprights are only partially parallel to the axis. Figures IA to ID are only a graphic illustration and not microsections. The yarn la is continuously guided over an inlet thread guide 5, consisting of two sliding bodies 6 and 7, at a speed VF. Figure IA shows a yarn cross-section at A. As a theoretical consideration, one can speak of a thread diameter FDl, which corresponds to the greatest thickness, measured over the outermost points of the loops. The textured filament la is then guided over a processing support 8, which has a convex shape towards a processing tool 9. The convex shape is formed in Figure 1 by a relatively large radius R. The processing tool 9 has a grinding coating 10 in Figure 1. The processing tool is shown as having both a synchronous rotation Vsgl. and a counter-rotation Vge. Both directions of rotation are possible. As a rule, synchronous rotation is preferred, but this requires a higher tool rotation speed. In previous tests, for example, at a thread speed of 400 m/min., the rotation speed of the grinding tool in synchronous rotation was set at 1600 to 1800 m/min. At a thread speed of 300 m, a counter-rotation speed of 300 m/min was selected. The convex shape of the processing support 8 now has the advantage that the parts protruding from the core, especially the loops 2 to the processing tool 9, protrude even further from their original position. However, on the side where the yarn rests on the processing support, the yarn flattens. This results in a slightly smaller thickness FD2 of the core. The flattening is caused by the slightly convex shape and a minimal tension "Z" on the yarn and has proven to be very advantageous. The

* ·· ft * · ft
• ft* &phgr; • ft · • • ft

Core diameter FK is only increased slightly during texturing, in contrast to diameter FD over the loops. This helps in that the setting of the processing gap SD* can be controlled relatively easily without the core being damaged by the processing tool. Figure IC now shows the cut C during the intervention of the processing tool with the smallest possible dimension SD. It has not yet been possible to test all possible qualities of yarn. The tests to date have shown that the yarn la should be guided in such a way that it does not come into the processing zone Wz, as otherwise there is a risk of damaging the core 4, if not even cutting the yarn. The yarn must not be guided around the tool or extend beyond the tangent T. Contrary to initial fears, the geometric shape of the processing support 8 in the area of the processing point Bs has not proven to be so critical. In Figure 1, this is almost a straight line, in contrast to the solution according to Figure 3 with a very small radius R of the processing support 8, or a much smaller curvature. After processing, the yarn Ib is guided again, namely through the outlet thread guide 11. Both thread guides 5 and 11 have proven to be very important for operational safety. The outlet thread guide 11 is also only shown schematically by two sliding bodies 12 and 13 respectively. Once the yarn has left the sliding body 13, the withdrawal direction can be selected. A constant tensile stress "Z" is preferably maintained throughout the entire process. Figure ID now shows a cross section of the processed yarn Ib with filament ends 14 protruding on one side. Since the course of the individual protruding loops mostly has a slightly helical component, the protruding ends 14 do not have a regular protruding direction, but are similar to the protruding ends of the fibers in spun yarn. If textured yarns other than those shown are processed, the protruding parts are reduced according to the cutting depth.

Figures 2, 3 and 4 show a complete device, wherein the machining tool is designed as a simple grinding wheel 9 and

- 11 -

is surrounded by a closed housing 20. In Figures 2 and 3, the numerical adjustment means 21 are assigned to the machining support 8', so that it is moved towards and away from the grinding wheel for adjustment, which is indicated with + and . The distance SD between the machining support 8, 8' and the machining tool can now be adjusted in two ways:

- Firstly, the open threading position E. For the open threading position E, a holder 22 is moved away from the processing tool by 5 to 10 mm via an eccentric 23 and a handle 24 against the tension of a spring 25. The unprocessed yarn la can be easily threaded in the open position after a cover 42 is swung open. For the fully open position, the eccentric is rotated past a dead position. If the handle is now turned back, the compression spring 25 ensures that the processing support 8 moves automatically into the preset working position.

Secondly, the working position SD. To adjust the processing position, the holder is adjusted in microsteps using an adjustment wheel 26 and threaded bolt 27 as well as threaded nut 28. The adjustment wheel 26 is coupled via an axis 29 to a counter 30, which is equipped with a step mechanism corresponding to an adjustment of 0.005 mm, for example. This allows the processing distance SD to be adjusted or set numerically in partial steps of 5 μm. The optimal value found in each case is recorded and stored for the processing or recycling of later yarn qualities of the same quality. In the area after the processing point, a suction opening 40 is arranged in the housing 20, from which the processing waste is sucked out via a suction line 41. The suction line 41 is attached to the cover 42, which is detachably connected to the housing 20. For optimal use of the entire grinding surface or according to the width of the grinding surface, the thread is moved laterally or transversely to the processing surface of a traversing device 43 with a corresponding linear back and forth movement 44 (Figure

- 12 -

4). The drive of the processing tool is driven by a high-speed motor M (not shown). The speed of the drive motor can be 5000 to 20000 rpm.

Figures 5 and 5a show the adjustment means 21 on a larger scale. The design shown is suitable for numerically adjusting an internal adjustment block, which is tensioned by the spring 25, with micro-millimeter accuracy using the adjustment wheel 26. On the other hand, by tensioning the spring 25, the processing support 8 can be retracted for threading and a threading gap can be created. If the thread should wind up on the processing tool during operation, the spring 25 can give way and protect the mechanical elements before any sensor stops the thread.

Figures 6, 7 and 8 show another particularly advantageous design with a double thread guide or two parallel thread runs. Here the housing is designed as a housing block

50, in which the processing tool, the thread guides, processing support, adjustment means and a traversing device

51 are arranged. The traversing device 51 is designed as a free-running traversing wheel driven by the thread itself, on the circumference of which two traversing grooves 52, 52' are provided. The cover 42 has a suction channel 53 which is connected to a suction pipe 54 and removes the processing waste (Figure 8). The two traversing grooves 52, 52" have the great advantage that two threads or two textured yarns la', la" can be processed simultaneously. Preferably, these are two identical yarn qualities. However, it is also conceivable that the same yarn, which has been processed once, for example, via the traversing groove 52, is guided in a second pass over the traversing groove 52', i.e. is processed twice. If two yarns are processed simultaneously, they are preferably guided around the traversing wheel on the left as shown in Figure 6. The traversing wheel moves counterclockwise. It is important here that the entire thread guide is doubled, 5, 5' or 11, 11' etc. The solution shown is also very practical for threading.

Claims (10)

13 - HLLuga92/DE-GM 23.11.95 Protection claims 1. Device for processing yarn,
characterized, that it has a machining point formed by a machining support and a driven grinding or cutting tool as well as micro-adjustment means for adjusting the machining depth. 2. Device according to claim 1,
characterized, that a thread guide is arranged at a distance before and after the processing point, such that the yarn is guided against the preferably convex grinding support in the operating state. 3. Device according to claim 1 or 2,
characterized, that the tool is designed as a high-speed grinding wheel, preferably with a diamond coating or as a knife mechanism, where the processing width is a multiple of the yarn diameter. 4. Device according to one of claims 1 to 3,
characterized, that a traversing device is arranged on the thread inlet side for the constant lateral displacement of the processing point, whereby the device is preferably designed with two thread runs. - 14 - 5. Device according to one of claims 1 to 4,
characterized, that the adjustment means has a micro-adjustment for the machining depth as well as a release for an open threading position, wherein the adjustment means preferably have a pre-tensionable spring. 6. Device according to claim 5,
characterized, that the adjustment means and the release are assigned to the correspondingly adjustable machining support, whereby the release preferably has two position ranges, a fully open locking position and an intermediate position, which automatically moves the machining support into the working position via spring tension and holds it in an exact working position. 7. Device according to one of claims 1 to 6,
characterized, that the setting means has a numerical position indicator for the processing depth, whereby the position indicator value is a relative reference value, usable for an identical reproducibility of the grinding depth, in particular for the same yarn quality. 8. Device according to one of claims 1 to 7,
characterized, that the grinding or cutting tool and the processing support are arranged in a closed housing, and the housing has a suction opening in the area after the processing point for suctioning off the processing waste, wherein the housing preferably has at least one further opening opposite the suction opening for generating a cross-flow to the yarn in the area after the processing point. ► · ■ ·· 9. Device according to one of claims 1 to 8,
characterized, that the housing is designed as a housing block which has the thread guides, the grinding support with the adjustment means, the grinding or cutting tool and a traversing device preferably for two thread runs. 10. Device according to one of claims 1 to 9,
characterized, that the processing support has a rounded support surface, wherein the thread guides are arranged in relation to the support surface in such a way that an angle of less than 180°, preferably of about 150° to 175°, is formed between the thread inlet and thread outlet.