EP1321412B1 - Conical cross-wound bobbin and method for winding the yarn package of a conical cross-wound bobbin - Google Patents

Description

The invention relates to a conical cheese and a method for forming the bobbin of a conical cheese with a thread guide according to the preamble of claims 1 and 6.

Yarn produced on rotor spinning machines differs from the ring spun yarn in the structure of the package and in the flow behavior. The rotor yarn is less hairy than the ring spun yarn and is therefore easier to unwind (easier lift off), but has a greater tendency to curl than the ring spun yarn, so that the wound yarn is pushed outwards in the edge region of the cheese from the overlying yarn layers. This can form beyond the normal spool stroke of, for example, 150 mm, grown up to a width of 170 to 180 mm cross-wound bobbin. In such a case, a desired coil structure with flat faces no longer comes off. Such phenomena occur with yarns of natural fibers such as cotton, especially coarse yarns, and are the more pronounced the coarser the yarn is.

Problems at the end faces of wound bodies can also occur in the preliminary stage of yarn production in wound fiber slivers or rovings. The US 954,344 describes that in Lunten or roving, which are not or only slightly rotated in the winding structure at the end faces Bulges occur. This disadvantageous effect occurs here, although the laying angle is more than 32 ° in the conventional art. This is favored by the soft and loose structure of the fiber strands. Such bulges can significantly affect the further processing of the winding body. According to US 954,344, the bulges are to be prevented in that the otherwise constant laying angle is increased in the edge region of the winding body.

If high speed yarn speeds are used in the package winding, medium and coarse yarns may cause the thread to move beyond the edge of the package at the deflection points of the lifting movement, resulting in a so-called skipping error. This error leads to yarn breaks and hinders the further processing of the yarn.

The probability that such errors occur is significantly affected by the crossing angle α. In the manufacture of cheeses, therefore, the choice of the respective crosshair angle is of great importance. While in the manufacture of a cross winding with "wild winding" the crosshair angle remains constant over the entire coil travel, the crosshair angle changes in a cross winding with "precision winding" by decreasing with increasing cross wound coil diameter. The advantages of precision winding include the fact that a cheese with precision winding has more run length with the same bobbin volume compared to a cross-wound bobbin in wild winding. However, the decreasing crossing angle with increasing cross-wound bobbin diameter limits the maximum allowable Diameter in the production of precision spools from staple fiber yarns, especially since staple fiber yarns can not be wound with arbitrarily small crossing angles in order to avoid the defects occurring at the edges. For this reason, as described, for example, in DE 100 15 933 A1, crossing angles of less than 28 ° should be avoided in rotor spinning. As a result, the precision winding, in particular when winding staple fiber yarns, only very limited useful.

In a third type of winding, the "step precision winding", an approximately uniform crossing angle over the coil travel is sought. Also, with the step precision winding, the above-described density problems or problems with the stability of the coil edge in practice only slightly reduced, but not resolved.

The generic DE-AS 26 32 014 shows a conical cheese, which is arigetrieben by circumferential friction of a roller. This drive roller has in the middle of a slightly protruding from its surface narrow friction zone with increased coefficient of friction. The drive should only take place in the predetermined region of the friction zone or the friction zone of the cross-wound bobbin. Nevertheless, the cross-wound bobbin to be wound with increasing bobbin diameter can make contact with the parts of the cylindrical drive device located to the left and right next to the predetermined friction zone. As a result, the coil is no longer driven solely in the friction zone, but also at other points of the circumference. Since conical coils, the coil circumference length is different seen over the coil axis, the speed of the cross-wound bobbin unsteady and uncontrollable. In order to avoid this, the crosshair angle of the cross-wound bobbin shown in DE-AS 26 32 014 or in the parallel US Pat. No. 4,266,734 is reduced in size compared to the crosshair angle outside of this friction zone in a narrow region opposite the narrow friction zone of the drive roller. As a result, the compressive strength of the bobbin is slightly increased within the predetermined limited range. The friction zone of the drive roller and the area with reduced crosshairs angle of the conical cheese are kept narrow.

New machine techniques, especially in weaving, such as air jet looms, place increased demands on the running properties of the yarn. The requirements can not or insufficiently meet with the known coil designs.

The invention has for its object to provide a comparison with known conical cheeses improved conical cheese and a process for their preparation on rotor spinning machines, especially when producing coarse yarns to create.

The object is achieved by a method according to claim 1 and a cross-wound bobbin according to claim 6.

The subclaims are directed to advantageous embodiments of the invention.

The invention is based on the finding that when compared to the crossing angle in the middle part larger crossing angles in the edge region of the cheese, the crossing angle in the remaining wider middle part can be significantly reduced compared to usual crossing angles, without the disadvantages occurring in a reduction of the crossing angle over the entire winding width disadvantages To have to buy. The reduction of the crossing angle can be driven considerably far without leading to an inadmissible hardening of the cross-wound bobbin.

The invention leads to an improved Ablauf.des thread from the cheese. The thread run is quieter, counteracts looping and Garnverhakungen and thus allows higher yarn withdrawal speeds. The coil structure, in particular at the end faces of the cross-wound bobbin, is improved. The run length of the yarn with the same bobbin diameter is significantly increased compared to a conventional bobbin of the same winding type.

The formation of the crossing angle α according to any one of claims 2 and 3 and 7 and 8 leads to an increase of the wound thread length, wherein an excellent stability of the conical bobbin can be achieved at high density. The crossing angle α advantageously increases steadily from the crossing angle α _{M of} the central zone to the crossing angle α _{R of} the edge zone. The edge zones can be dimensioned such that they occupy no more than 15% of the total winding width B _WG .

Each made with increasing coil diameter reduction of the coil contact pressure according to claim 4 and A reduction of the thread tension according to claim 5 ensures the suppression of an undesirably high yarn pressure at cross angles α according to the invention, which are smaller than 28 °. The coil contact pressure is known to be composed of the weight of the coil and the weight of the coil frame and the force resulting from the torque applied by, for example, a torque transducer. The coil contact pressure can be reduced so that not only the coil weight is compensated, but beyond discharge occurs.

If a reciprocating thread guide, for example a belt thread guide, already exists at a winding station for generating the traversing motion whose speed can be controlled separately from the reel speed, the method according to the invention for producing a cross-wound bobbin without additional structural complexity and without replacement of Run thread guide elements by the appropriate means or programming the controller in a simple manner.

The invention makes it possible to wind even coarse yarns with relatively low crossing angles. For example, the processing of cotton yarn with Nm 20 at a crossing angle α of 25 ° with the associated good flow properties and long run lengths still possible. Improved drainage characteristics reduce downtime by reducing the number of thread breaks during further processing of the bobbins. With the run length becoming larger as a result of the reduction in the crossing angle, it is possible to achieve a yarn quantity increased by about 15% to 25% on a conical cheese according to the invention is wound opposite a conventional coil with the same coil diameter. This leads to a significant reduction in the number of coils of a lot. This not only reduces downtime for the bobbin change at the spinning and winding stations, but also the transport costs and the transport volume during bobbin transport are reduced. The cost of handling the coils in subsequent yarn processing processes can be reduced.

The invention improves productivity and makes it possible to reduce costs and thus to increase overall economy in yarn production and processing.

Further details of the invention will be explained with reference to FIGS.

Fig. 1

eine Seitenansicht einer Spinnstelle zur Durchführung des erfindungsgemäßen Verfahrens in vereinfachter schematischer Darstellung,

Fig. 2

die vereinfachte Prinzipdarstellung einer erfindungsgemäßen konischen Kreuzspule,

Fig. 3

den Verlauf des Kreuzungswinkels α über einen Hub vereinfacht als Kurve dargestellt.

It shows:

Fig. 1

a side view of a spinning station for carrying out the method according to the invention in a simplified schematic representation,

Fig. 2

the simplified schematic diagram of a conical cheese according to the invention,

Fig. 3

the course of the crossing angle α over a stroke simplified illustrated as a curve.

FIG. 1 shows a winding device 1 at a spinning station of a rotor spinning machine producing a conical cheeses. The winding device 1 has a roller 2, which drives the conical cheese 3 by means of friction.

The roller 2 rotates in the direction of arrow 4. The cheese 3. is supported by a pivoting creel 5 and rests on the roller 2. The roller 2 is acted upon by a contact pressure. The thread 6 is withdrawn in the direction of the arrow 7 by means of cooperating as a pair of rollers take-off rollers 8, 9 of the spinning box 10 of the spinning station with constant yarn speed and wound on a yarn 6 reciprocating yarn guide 11 as a bobbin 12 of the cheese 3. The yarn guide 11 is part of a traversing device 13 which is connected via an operative connection 14 with the motor 15 and driven by this. The roller 2 is driven via the shaft 16 by a motor 17. Both the motor 15 and the motor 17 are controlled by a microprocessor 18, wherein the crossing angle α of the conical cheese 3, depending on the position of the yarn guide 11, is controllable during the respective Spulenhubes.

The conical cheese 25 shown in Figure 2 shows a wound on the bobbin 26 according to the invention wound bobbin 27. The bobbin 27 has in the edge zones 28, 29, a cross winding with the crossing angle α _R and in the middle zone 30, a cross winding with the crossing angle α _M up. In this case, α _R in the exemplary embodiment of FIG. 2 is 35 ° and α _M is 25 °. The width of the zone 30 and the edge zones 28, 29 are each marked by a dashed line. The winding body 27 is shown in a simplified schematic diagram, the respective course of the laid thread 6 is only partially indicated, but can be different degrees of crossing α detect. The width B _{WG of} the cheese 25 from the left spool edge 33 to the right spool edge 34 is in the embodiment 150 mm. The width B _WG corresponds to a stroke of the yarn guide 11.

By inertial forces, which can be effective at the high speeds of the traversing movement even with the relatively low mass of the thread 6, especially coarse threads, and which occur by reversing the motion when reciprocating yarn guide 11, the transition from a value of the crossing angle α not abruptly to another value, as shown in the schematic representation of Figure 2, but fluently.

In that regard, the representation of Figure 3 of the actual formation of the crossing angle α of the cheese 25 or the thread pattern on the lateral surfaces is closer than the representation of Figure 2.

FIG. 3 shows the progression of the size of the crossing angle α shown as curve 31 over the winding width B _{WG of} the conical cross-wound bobbin, the values representing the stroke of the thread guide 11 in the representation of the cross-wound bobbin 25 of FIG. 2 from left to right (stroke of the thread guide 11) during the forward movement). At the left-hand turning point of the yarn guide 11 or the left-hand coil edge 33, the crossing angle α passes through the zero point and reaches the value of α _R = 35 ° in the left-hand edge zone 28. From α _R = 35 °, the value decreases after a transitional range down to α _M = 25 °. The value of α _M = 25 ° is kept constant in the middle zone 30. On the right side of the cheese 25, the value of α _M = 25 ° again increases to α _R = 35 ° in the right edge zone 29 and then passes through the right Reversal point of the thread guide 11 and the right-hand coil edge 34 again the zero point. The width of the central zone 30, in which the crossing angle α is at the value of α _M = 25 °, occupies more than 60% of the winding width B _WG . The course of the size of the crossing angle α during the stroke of the yarn guide 11 in the return movement to the left is indicated by dashed lines in Figure 3.

The setting of the crossing angle α is made in a known per se and therefore not explained in more detail manner by controlling the rotational speed of the cheese 3, 25 and the speed of traversing movement of the yarn guide 11 during the stroke. The cross-wound bobbin 25, which is designed with an angle of intersection α of α _R = 35 ° in the edge zones 28, 29, has stable coil edges 33, 34, without unduly high pressing pressure being exerted. As a result, bulges are avoided on the end faces of the cheese 25. The advantageously low crossing angle α of α _M = 25 ° in the lying between the edge zones 28, 29 zone 30 allows a higher run length with stable bobbin with the same finished diameter of, for example, 300 mm of the cheese 25, thereby 15% to 25% more yarn contains as usual coils of the same diameter.

The running behavior of the cheeses 3, 25 is improved by a quieter yarn path and the suppression of loops and Garnverhakungen.

The invention is not limited to the illustrated embodiments. The thread guide may alternatively be formed, for example, as a belt thread guide or as a grooved roller. The crossing angle α can advantageously assume alternative values in a range of 30 ° to 40 ° in the edge zones 28, 29 and in the middle zone 30 in a range of 15 ° to 28 °.

Claims (8)

1. Method for forming the yarn package (12, 27) of a conical cross-wound bobbin (3; 25) of rotor yarn (6) with a thread guide (11), which is adjusted in such a way that, within a winding traverse in a central zone (30) of the winding traverse, the crossing angle a is smaller than in the remaining part of the winding traverse, characterised in that in the central zone (30), a crossing angle α_M of less than 28° and greater than 15° α_M is executed and in that the central zone (30) with the crossing angle α_M is produced over more than 50% of the entire winding width B_WG.
2. Method according to claim 1, characterised in that the crossing angle α_M in the central zone (30) is formed with a value between 20° and 26°.
3. Method according to claim 1 or 2, characterised in that the crossing angle α_M in the central zone (30) is formed at least 8° smaller than the maximum crossing angle α_R in the edge zones (28, 29).
4. Method according to any one of the preceding claims, characterised in that the bobbin contact pressure is reduced as the bobbin diameter increases.
5. Method according to any one of the preceding claims, characterised in that the thread tension is reduced as the bobbin diameter increases.
6. Cross-wound bobbin (3; 25) with a conical yarn package (12; 27), in which, in each case, within a yarn position, the crossing angle α in a central zone (30) of the winding traverse is smaller than in the remaining part of the winding traverse, characterised in that the crossing angle α_M in the central zone (30) is smaller than 28° and greater than 15° and in that the central zone (30) takes up more than 50% of the entire winding width B_WG.
7. Cross-wound bobbin according to claim 6, characterised in that the crossing angle α_M in the central zone (30) is at least 8° smaller than the maximum crossing angle α_R in the edge zones (28, 29).
8. Cross-wound bobbin according to claim 6 or 7, characterised in that the crossing angle α_M in the central zone (30) is between 20° and 26°.

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