EP1625091B2 - Strip winding method - Google Patents

Abstract

The invention relates to a method for winding a continuously fed strip (5) onto a reel (2) while turning said reel (2) and by moving the strip (5) in a to-and-fro manner by means of a traversing device (4) over the entire length of the reel (2) at a laying angle (a). The invention provides that, when the reel diameter has increased by a certain value, the laying ratio, which is the ratio between the rotational speed of the reel and the to-and-fro motion (cycle to-and-fro) of the traversing device, is changed step-by-step each time in such a manner that the laying ratio changes by, in essence, whole increments.

Description

The invention relates to a method for winding a continuously fed tape on a spool while rotating the spool and reciprocating the tape by means of a traversing device over the entire length of the spool at a laying angle, each time the spool diameter has increased by a bestimmmten value , the laying ratio, that is the ratio between the reel speed and the reciprocating motion (double stroke) of the traversing device, is changed stepwise.

Such a method for winding a continuously fed tape is referred to in the art as "stepped precision winding" and is for example from the DE 41 12 768 A , of the DE 42 23 271 C1 and the EP 0 561 188 the latter gives a detailed overview of various types of coil shapes.

The winding of the tape takes place in winding machines on cylindrical or conical coil cores, wherein the feed rate of the tape is relatively constant on the spool core, as given by the winder upstream banding machines.

1. 1) Der Verlegewinkel α, das ist jener Winkel zwischen einer Normalen auf die Spulen- Drehachse und der Längsrichtung des auf die Spule zugeführten Bandes.
2. 2) Das Verlegeverhältnis V, das ist die Anzahl an Spulenumdrehungen pro Changiereinrichtungs-Doppelhub.

The appearance, strength and quality of the coils is significantly influenced by the following parameters:

1. 1) The laying angle α, which is the angle between a normal to the coil rotation axis and the longitudinal direction of the fed to the coil tape.
2. 2) The laying ratio V, which is the number of spool revolutions per reciprocator double stroke.

From the chosen laying ratio V, the laying angle α is set.

A stepped precision winding is a hybrid of two basic winding methods of how the fed tape can be wound on a spool core, namely the "wild winding" and the "precision winding".

The characteristic of the wild winding is a constant laying angle α, but a variable ratio between the speed of the reel and the traversing speed (= variable laying ratio V). In the installation ratio / coil diameter diagram of Fig. 2 three graphs for wild windings are plotted with the laying angles α = 4 °, 5 °, 6 °. An advantage of the wild winding is the simple structure of the necessary for their production winding machine, which in Fig. 3 is shown in side view and plan view. This may in the simplest case comprise a motor 10 which drives a drive roller 11, which in turn acts on the circumference of the spool 12 and drives it at a constant peripheral speed, so that the belt 19 is wound at a constant linear speed. The winding spindle 18 of the spool 12 may be free-running. The motor 10 drives a traversing mechanism 13 via a transmission gear, consisting of pulleys 15, 16 and a belt 17 running over the two pulleys, so that the traversing belt guide 14, through which the belt 19 runs, moves at a constant lifting speed (traversing stroke). and moved. Thus, there is a fixed gear ratio between the peripheral speed of the spool 12 and the traversing stroke of the traversing belt guide 14, which results in a constant laying angle of the belt 19 on the spool 12. This means that the laying angle at the beginning of the winding process on an empty bobbin is the same as at the end of the winding process when the bobbin has reached its largest diameter. Disadvantageously, this reduces the number of turns per winding layer with increasing coil diameter steadily, so that a coil with different packing density of the strip material is produced at each coil diameter. Another unpleasant spooling effect, referred to as "image winding," occurs in certain ratios of spool diameters and traversing speeds, in which several tape layers come to lie almost exactly one above the other at these ratios, causing the roll to become unstable. Therefore it is necessary to take measures for "picture disturbance", eg wobble.

The precision winding in turn is characterized by a constant installation ratio over the entire growing coil diameter, which in turn means that the laying angle decreases with increasing coil diameter. In the diagram of Fig. 2 is a precision winding with a laying ratio V = 35 entered as a straight line. The advantage of precision winding is the achievement of a coil with constant packing density of the strip material on the coil independent of the coil diameter. The disadvantage of the precision winding is that - starting from an initial laying angle at the beginning of winding the strip material on an empty bobbin - the laying angle with increasing bobbin diameter is ever smaller and eventually so small (it theoretically approaches zero), that the winding is unstable becomes. The structure of a winding machine for generating a precision winding is in Fig. 4 shown in side view and top view. This winder comprises a motor 20 which rotates a winding spindle 21. On the winding spindle 21 is rotatably a coil core 26, on which a tape 27 is wound to form a coil 22. A traversing device 23 is connected via a spur gear 25 with the winding spindle 21. The traversing device 23 has rotational / translational means, not shown, for reciprocating the traversing belt guide 24 in traversing strokes. Due to the direct rotary drive of the winding spindle 21st For example, the speed of the motor 20 must be steadily reduced as the diameter of the forming coil 22 increases since the tape to be wound is fed by a constant linear velocity banding device.

In order to mitigate the respective disadvantages of the wild winding and the precision winding and to combine their advantages, the "stepped precision winding" has been proposed in the past. This winding method is based on the idea that the laying ratio between predefined limiting diameters of a coil is kept constant and is gradually changed to a different value when a respective limit diameter is reached, the values of the laying ratios being chosen such that a graph of the laying ratio over the coil diameter is approximately follows the graph of a wild winding for a given laying angle. The advantage of stepped precision winding is that, on the one hand, "image windings" are avoided, since the sudden change in the laying ratio represents a "picture disturbance measure".

On the other hand, the laying angle is not much smaller than the initial laying angle even with increasing coil diameter.

While the stepped precision winding for the production of yarn and bobbins provides the expected good result, surprisingly poor results are often obtained in the production of wound coils with stepped precision winding. The shortcomings of these tape reels range from unsightly because of irregular optical appearance to reels with varying, e.g. Wavy diameter over its length, over irregular end faces of the coil, up to unstable winding structure.

Since such coils are usually used in high-speed machines, such as rotary looms, any irregularity of the coil structure can have fatal consequences that lead as the least effect to breakage of the tape when pulling off the coil, in the worst case, the destruction of a part of the machine , Such damage is caused by imbalance on irregular coils, by vibration of the bands during peeling, which gradually aufschaukelt, etc. Furthermore, irregular coils heat quickly when pulling off the tapes and thereby lead to fatigue and weakening of the strip material, especially if it is is about stretched plastic tape.

For this reason, there is a strong industry need for an improved stepped precision winding process.

The present invention provides such an improved stepped precision winding method, which is characterized in that, in the stepwise change of the laying ratio, it is changed by substantially integral steps. Namely, the inventors have recognized that the reason for unsatisfactory buildup of coils in stepped precision winding is the sudden change in the layer pattern of the tapes resulting from the stepwise change in the laying ratio, which is a discontinuity for the overall structure of the coil. In unfavorable cases, these altered layer images accumulate and lead to the aforementioned irregularities or uneven packing density. By virtue of the measure according to the invention, however, even after the stepwise change of the laying ratio, the layer image remains essentially unchanged, so that a coil with an excellent structure, i. regular appearance and high packing density. A gradual change in the laying ratio by substantially integral steps should be understood to mean that the fractional part of the laying ratio changes at most by 0.1, preferably at most 0.03, more preferably at most 0.01 at each change.

According to the invention, each time the ratio is changed, the fractional part of this ratio is changed to the extent that there is a constant partial coverage with an underlying band track. This achieves a very stable coil construction.

At an integer laying ratio, i. a laying ratio without comma, picture windings set on the coil. In order to exclude image windings which render the coil structure unstable, it is further proposed according to the invention to select the laying conditions so that their fractional part is at least two digits. Furthermore, it is preferred for coils with plastic tapes to choose the laying ratios close to 0 or 0.50 or 0.33 or 0.25, whereby the reversal points of the tape at the end of the coil after one, two, three or four double strokes of the traversing belt guide come close to each other again. Depending on the width of the aufzuspulenden tapes, the laying ratio can each be changed so that results in a forward or backward tape laying or is maintained.

Furthermore, it is possible empirically to specify specific laying angle ranges for respective widths of the tapes and their material properties, which ensure optimum construction of the coil. In order to achieve this optimum coil construction it is provided that the laying ratio is changed so that the resulting laying angle remains within this predetermined range. For stretched plastic tapes with a width between 2 and 10 mm, for example, a laying angle range of 4 to 6 ° has proven to be advantageous.

In order to adjust the laying conditions according to the invention with the required accuracy, the coil is driven by a separate motor and the traversing device also by a separate motor and the change of the laying ratio is done electronically by gradually changing the ratio of Speeds of the two motors to each other wherein in the stepwise change of the ratio of the speeds of the two motors, the laying ratio is changed by substantially ganzzalhige steps, so that the comming rate of the laying ratio at each change is changed by at most 0.1. Particularly well controlled are motors that are constructed as three-phase drives with frequency converter, or as DC drives.

Furthermore, the current coil diameter can be calculated with high precision from a nominal / actual comparison of linear belt speed and coil speed.

• Fig. 1 den prinzipiellen Aufbau einer Spulmaschine zur Durchführung des erfindungsgemäßen Verfahrens;
• Fig. 2 ein Diagramm, in dem Graphen des Verlegeverhältnisses über dem Spulendurchmesser für drei Wilde Wicklungen mit Verlegewinkeln α = 4°, α = 5° und α = 6°, für eine Präzisionswicklung V = 35 und für eine gestufte Präzisionswicklung SPW eingetragen sind;
• Fig. 3 die eingangs erklärte Spulmaschine nach dem Stand der Technik zur Erzeugung einer Wilden Wicklung;
• Fig. 4 die eingangs erklärte Spulmaschine nach dem Stand der Technik zur Erzeugung einer Präzisionswicklung;
• Fig. 5 zeigt die Lage von Umkehrpunkten des Bandmaterials an der Stirnseite einer Spule;
• Fig. 6 bis Fig. 9 zeigen verschiedene Konfigurationen übereinanderliegender Bandspulen; und
• Fig. 10 und Fig. 11 zeigen eine vorwärtslaufende bzw. rückwärtslaufende Bandgutverlegung.

The invention will now be explained in more detail by means of embodiments with reference to the drawings. In the drawings show:

• Fig. 1 the basic structure of a winding machine for carrying out the method according to the invention;
• Fig. 2 a diagram in the graphs of the laying ratio over the coil diameter for three wild windings with laying angles α = 4 °, α = 5 ° and α = 6 °, for a precision winding V = 35 and for a stepped precision winding SPW are entered;
• Fig. 3 the prior art winder according to the prior art for generating a Wild winding;
• Fig. 4 the above-explained winding machine according to the prior art for producing a precision winding;
• Fig. 5 shows the location of reversal points of the strip material on the end face of a coil;
• FIG. 6 to FIG. 9 show various configurations of superimposed tape reels; and
• 10 and FIG. 11 show a forward or reverse running Bandgutverlegung.

A winding machine for carrying out the method according to the invention, which in Fig. 1 is shown in simplified form, has at least one, but usually a plurality of drivable winding spindles 1 in a pivot bearing. On the winding spindle 1, a non-illustrated spool core is rotatably attached, is wound onto the strip material 5. The strip material 5 is fed at substantially constant linear velocity from a banding device. Such banding devices are known per se and not part of the invention, so that no further explanation is required. Each winding spindle 1 or the tape spool 2 which builds up on the spool core is rotated by a contact roller 3, which is rotatable about its own axis and is in circumferential contact with the spool 2 and is driven by a motor M1. Furthermore, a reciprocating over the length of the winding spindle reciprocating device 4 is provided, which has a loop-shaped traversing belt guide 6, through which the tape 5 passes and which the band 5 in a laying angle α on the coil 2 supplies. The laying angle α is defined as the angle between the supplied belt 5 and a normal S on the coil axis A. The winding length L is that axial length in which the winding spindle 1 is wound with the belt 5. In other words, the Bewicklungslänge L corresponds to the coil length and two Bewicklungslängen represent the length of a double stroke of the traversing device 4.

The winder is operated in a stepped precision winding process. This means that, starting from a start laying angle when winding the tape onto a spool core, a certain laying ratio is initially maintained (as a result of which the laying angle changes). When the diameter of the bobbin reaches a predetermined value, the laying ratio is gradually set to a new value, and this in turn is maintained until the bobbin diameter is increased to another predetermined value, whereupon the laying ratio is again set to a new value stepwise.

The adjustment of the laying ratio is done by an "electronic gear", i. an electronic control of the ratio of the speeds of the motor 2 driving the coil 2 and a motor M2 reciprocating the traversing device 4. The virtual "gear ratio" of the two motors is changed electronically when reaching a certain diameter again stepwise by the traversing M2 is given a changed speed. The drives M1, M2 are preferably three-phase drives with frequency converter, or DC drives.

The instantaneous bobbin diameter is calculated, for example, from a nominal / actual comparison of the thread linear speed and the bobbin rotational speed.

In the diagram of Fig. 2 shows the graph SPW the step-shaped course in the step precision winding, according to the invention, the laying ratio is changed stepwise by substantially integral steps. From the beginning of winding a tape on a spool core of 45 mm diameter, a preset laying ratio V = 30,557 is initially maintained until the spool diameter reaches 50 mm, whereupon the laying ratio V is set to 27,551 until the spool diameter reaches 55 mm, whereupon the laying ratio V is changed to 24.546. This incremental change in the laying ratio is made by 5 mm with each coil diameter increase, up to a diameter of 95 mm (V = 13.525). From then on, the change in the laying ratio is only after every 10 mm bobbin diameter increase, from 125 mm bobbin diameter only every 15 mm bobbin diameter increase, and finally from 155 mm bobbin diameter only every 20 mm bobbin diameter increase. One recognizes from the diagram of Fig. 2 that the entire course of the graph SPW remains within the limits given by the graphs of the wild windings with the laying angles α = 4 ° or α = 6 °, ie the laying angle varies in the Sufenpräzisionswicklung, but only within the low bandwidth between 4 and 6 °. In fact, the course of the graph follows SPW approximately that of a wild winding with α = 5 °, but without even coinciding with this graph or run parallel, since in such a section then the coil has the properties of a wild winding with the associated problems of "image wraps" would have. Table 1 shows the winding ratios of the graph SPW, wherein in column 1 the respective coil diameters are indicated, in which a change in the laying ratio to the values in column 2 takes place. Column 3 shows the advance percentage of the laying ratio, which indicates how many complete revolutions the coil performs per double stroke of the traversing device. Column 4 shows the fractional part of the laying ratio, from which the offset angle shown in column 6 can be calculated, which indicates by how many degrees the reversal point of the belt is offset after a double stroke of the traversing device with respect to the previous reversal point. Column 5, in turn, shows the post-decimal difference between successive laying ratios. It can be seen that this difference in the decimal point is in the thousandth range, ie, that the changes in the installation ratio are substantially integer. <u> Table 1 </ u> Coil diameter [mm] installation ratio integer part fractional Fractional difference Offset angle [°] 45 30.557 30 0.557 200.52 50 27.551 27 0.551 0,006 198.36 55 24.546 24 0.546 0.005 196.56 60 22.542 22 0.542 0,004 195.12 65 20.538 20 0,538 0,004 193.68 70 18.534 18 0.534 0,004 192.24 75 17.533 17 0.533 0.001 191.88 80 16.531 16 0.531 0,002 191.16 85 15.529 15 0.529 0,004 190.44 90 14.527 14 0.527 0,002 189.72 95 13.525 13 0.525 0,002 189 105 12.523 12 0.523 0,002 188.28 115 11,522 11 0.522 0.001 187.92 125 10.52 10 0.52 0,002 187.2 140 9.518 9 0.518 0,002 186.48 155 8.516 8th 0.516 0,002 185.76 175 7,514 7 0.514 0,002 185.04

In order to exclude "image windings", the fractional part of all laying conditions was chosen so that at least two decimal places are provided in each case; in fact, the laying conditions, with the exception of the coil diameter of 125 mm, even have three decimal places. The decimal fraction is close to 0.5 (actually between 0.557 and 0.514), so that after two double strokes of the traversing device, the reversal point of the band comes to lie again close to the previous reversal point. Further preferred value ranges for the fractional part of the laying ratio are close to 0 or 0.33 or 0.25. However, none of these values should themselves be used, since otherwise image windings would occur with each double stroke or after three or four double strokes of the traversing device. For a better understanding of the relationship between the fractional part of the laying ratio and the offset angle is in Fig. 5 schematically shows a coil 2 from the front side, which consists of strip material which is wound on a spool core 8 with a Verlegeverhältnis having a decimal portion of slightly more than 0.25, for example, 0.26. From this an offset angle of just over 90 ° can be calculated. Starting from point 30, which represents a reversal point of a band winding, the band material is deposited on the bobbin on each double stroke of the traversing device so that the reversal point shifts by approximately 90 ° on the circumference of the coil, resulting in a sequence of reversal points 30 → 31 → 32 → 33 → 34 results as shown by the dashed arrows. It can be seen that the reversal point 34 is close to the reversal point 30, ie that after four double strokes of the traversing device, the band layers come to lie next to one another.

Furthermore, it is preferable to adjust the laying ratio in each case so that there is a constant partial coverage of the wound tape with an underlying tape track. When winding tapes on spools, the following configurations of superimposed tape tracks may result in the FIGS. 6 to 9 are shown. These configurations depend on the laying ratio, the laying angle α, the width b of the tapes 5 and their axial offset d. In Fig. 6 The bands lie exactly edge to edge. In Fig. 7 The bands are in between with a gap. In FIGS. 8 and 9 The band tracks partially overlap, as is preferred according to the invention. This results in Fig. 8 a reverse-running conveyor belt laying and in Fig. 9 a forward belt conveyor.

wobei gilt:

V =

Verlegeverhältnis (z.B. auf vier Kommastellen gerundet)

Vz =

Verlegeverhältniszahl (ganzzahlig, gewählter Vorkommaanteil des Verlegeverhältnisses V)

na =

Abbindungszahl (ganzzahlig, jene Anzahl Doppelhübe bei der es zu dem definierten Versatz d kommen soll)

L =

Bewicklungslänge der Spule in mm (2L → Doppelhub)

d =

Versatz in mm (entlang der Wickelachse)

In the winding method according to the invention, with each change in the laying ratio, the fractional part of this ratio is changed to the extent that there is a constant partial covering with an underlying band track. The relationship between the axial offset d and the laying ratio V can be determined from the following formula: $$\mathbf{V}\mathrm{=}\frac{{\mathrm{n}}_{\mathrm{a}}\mathrm{x}\mathrm{2}\mathrm{L\; x}\left({\mathrm{V}}_{\mathrm{z}}\mathrm{+}\mathrm{1}\mathrm{/}{\mathrm{n}}_{\mathrm{a}}\right)}{{\mathrm{n}}_{\mathrm{a}}\mathrm{x}\mathrm{2}\mathrm{L}\mathrm{-}\mathrm{d}}$$

where:

V =

Installation ratio (eg rounded to four decimal places)

Vz =

Relocation ratio (integer, selected precomport part of the installation ratio V )

na =

Abbindungszahl (integer, the number of double strokes at which it should come to the defined offset d )

L =

Winding length of the coil in mm (2 L → double stroke)

d =

Offset in mm (along the winding axis)

With the above formula, the skilled person can determine the required laying ratio V from a desired offset d. In practice, it has proven useful for a construction of a coil with excellent stability, the offset d to be chosen so that an overlap of the ribbon of about a ½ ribbon width b sets (see FIGS. 8 and 9 ). A negative sign of the offset means "forward" routing.

In a "forward-running" Bandgutverlegung the accumulating on the coil 2 band 5 is deposited in front of the located on the rotating in the direction of arrow 9 coil 2 5a, as in Fig. 10 shown. In a "reverse-running" Bandgutverlegung the accruing to the coil 2 band 5 is stored behind the on the rotating in the direction of arrow 9 coil 2 5a, as in Fig. 11 shown. However, forward and reverse tape laying does not only affect adjacent layers. According to the invention, it is also preferable to always change the laying ratio when reaching a diameter limit so that a forward or backward running tape laying also results or is maintained in this stepwise change. This also means that the change in the offset angle takes place so that the offset angle either ever larger or - as shown in Table 1 - is getting smaller, which contributes to a particularly regular construction of the coil.

The above formula can also be reformulated in such a way that the offset d can be calculated with knowledge of the laying ratio: $$\mathbf{d}\mathrm{=}{\mathrm{n}}_{\mathrm{a}}\mathrm{x}\mathrm{2}\mathrm{L}\mathrm{-}\frac{{\mathrm{n}}_{\mathrm{a}}\mathrm{x}\mathrm{2}\mathrm{L\; x}\left({\mathrm{V}}_{\mathrm{z}}\mathrm{+}\mathrm{1}\mathrm{/}{\mathrm{n}}_{\mathrm{a}}\right)}{\mathrm{V}}$$

Claims (7)

1. A process for winding a continuously supplied band (5) onto a bobbin (2), with the bobbin (2) being rotated and the band (5) being reciprocated along the entire length of the bobbin (2) at a winding angle (α) by means of a cross-winding device (4), wherein each time the bobbin diameter has increased by a particular value, the winding ratio, i.e. the ratio between the number of bobbin rotations and the reciprocating motion (to-and-fro stroke) of the cross-winding device, is changed in steps, with the bobbin (2) being driven by a separate motor (M1) and the cross-winding device (4) also being driven by a separate motor (M2), characterized in that the change in the winding ratio is performed electronically by stepwisely changing the ratio of the speeds of the two motors and that, with the stepwise change, the winding ratio is changed in essentially integral steps so that, with each change, the post-decimal point part of the winding ratio will change by 0.1 at the most, preferably 0.03 at the most, more preferably 0.01 at the most, and that, with each change in the winding ratio, the post-decimal point part of said ratio is changed to such a degree that a constant partial overlap with an underlying band track will result, wherein an axial shift d to the extent of the desired constant partial overlap is selected and the winding ratio is calculated from the following formula: $$\mathbf{V}\mathrm{=}\frac{{\mathrm{n}}_{\mathrm{a}}\mathrm{x}\mathrm{2}\mathrm{L\; x}\left({\mathrm{V}}_{\mathrm{z}}\mathrm{+}\mathrm{1}\mathrm{/}{\mathrm{n}}_{\mathrm{a}}\right)}{{\mathrm{n}}_{\mathrm{a}}\mathrm{x}\mathrm{2}\mathrm{L}\mathrm{-}\mathrm{d}}$$

   

   
   wherein the following applies:

   V = winding ratio (f.i. rounded to four decimal places)

   Vz winding-ratio number (integral, selected pre-decimal point part of winding ratio V)

   na = tie number (integral, number of to-and-fro strokes at which the defined shift d is supposed to occur)

   L = winding length of the bobbin in mm (2L → to-and-fro stroke)

   d = shift in mm (along the winding axis)
2. A winding process according to claim 1, characterized in that the post-decimal point part of the winding ratio is at least two-digit and preferably is close to 0 or 0.50 or 0.33 or 0.25.
3. A winding process according to claim 1 or 2, characterized in that the winding ratio is changed such that a forward or backward-moving band winding is created.
4. A winding process according to any of claims 1 to 3, characterized in that the winding ratio is changed such that the resulting winding angle (α) will stay within a predetermined band width.
5. A winding process according to claim 1, characterized in that the motors (M1, M2) are rotary-current drives with frequency converters or direct-current drives.
6. A winding process according to any of the preceding claims, characterized in that the instantaneous bobbin diameter is calculated from a variance comparison of the linear band speed and the number of bobbin rotations.
7. A winding process according to claim 1, characterized in that, depending on the winding angle (α), the shift d is selected such that an overlap of bands of appx. ½ a bandlet width b emerges.

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