EP0556386B1 - Method and device for determining the diameter of a bobbin at a spinning point on a spinning machine - Google Patents

Abstract

The invention concerns a method for determining the diameter of a bobbin at a spinning point on a spinning machine processing slivers, plus a device for carrying out this method. The aim is to avoid the disadvantages described in the application and to determine the diameter of each bobbin simply and without any direct contact with the bobbin.

Description

The present invention relates to a method for determining the diameter of a bobbin at a spinning station of a spinning machine, in which a sliver of known strength is fed to the spinning station at a certain speed, spun there into a thread and then from there at a defined ratio to the sliver feed speed Take-off speed is drawn off and wound onto the spool with a winding speed matched thereto, and a device for carrying out this method.

In order to determine the diameter of the coil, it is known to implement a variable stop with respect to the coil surface. The variable stop is a mechanical measure to determine the changing coil diameter at the desired times. In this context, the use of mechanical sensors that continuously or discontinuously contact the coil surface is common.

As practice shows, the prerequisite for accurate functioning is that hard-wound bobbins are always produced, which is a limitation. In the case of softly wound coils, the solution mentioned has the disadvantage that by pressing in the variable stop on the surface of the coil the signal to be formed for the coil diameter is falsified. This fact leads to inaccuracies which reduce the probability of success for detecting a thread end after thread break in the first attempt or otherwise initiate the bobbin change inaccurately. The mechanical scanning of the coil diameter by means of a button (DE-OS 38 27 345) does not eliminate the disadvantages shown in the prior art.

With the use of non-contact sensors, a second way of detecting the diameter of the bobbin is recognizable. An optical sensor continuously determines the changing diameter of the coil without having to mechanically touch the surface. An optical scanning (DE-OS 36 17 151, Fig. 3) has the disadvantage that the optics on the textile machine can become dirty with dust, fibers and other particles, which has the consequence that the signal obtained is falsified.

A third possibility (US-A-3 877 209) according to the prior art consists in the detection of the rotational speed of the take-off roller or winding roller, on the basis of which the yarn length and thus the diameter of the package are determined.

This solution has not been used in particular for the positioning of a thread take-up device with respect to a bobbin surface, since practical influencing factors which falsify the constant gap formation between the surface of the package and the thread take-up device are not taken into account. However, these influencing factors also lead to inaccuracies in determining the point in time for initiating the coil change.

• unterschiedlich harte, evtl. eingelaufene Druckroller, was zu unterschiedlichem Schlupf an den Abzugswalzen führt;
• ungleichmäßig abgenützte Mitnahmegummis auf den Friktionswalzen, was eine unterschiedliche Aufwindespannung zur Folge hat.

Such influencing factors are

• differently hard, possibly run-in pressure rollers, which leads to different slip on the take-off rollers;
• unevenly worn driving rubbers on the friction rollers, which results in a different winding tension.

Due to the variety of spinnable materials and different manufacturing parameters (yarn strength, winding tension), different yarn thicknesses and winding hardness are common, which make a sensorless determination of the bobbin diameter as a reference variable for the control appear inaccurate than when using diameter-sensing sensors.

The object of the present invention is to provide a method and a device which avoid these disadvantages and make it possible to determine their respective diameters in a simple manner without directly scanning the coil.

This object is achieved in that under given conditions (yarn strength, winding tension) the yarn thickness corresponding to a certain bobbin diameter is empirically determined, that taking into account possible production interruptions at this spinning station, the yarn length generated is measured, that from the product of the tape thickness with the quotient Tape feed speed and thread take-off speed, the yarn thickness is determined, that from the quotient of the wind-up speed and the take-off speed, a parameter for the winding hardness of the bobbin is determined, that the determined yarn strength and the winding tension corresponding to the determined winding hardness with the yarn thickness and the winding tension, that of the empirical yarn length determination for the specific bobbin diameter have been compared, and any deviation that may arise is used as a correction factor for the yarn length when determining the actual bobbin diameter. The empirical determination of the yarn length serves to create a reference value. The length of the yarn can be measured during the production of a bobbin by directly scanning the yarn fed to the bobbin; Of course, even after the production of a bobbin, ie after it has reached its desired size, the yarn can be unwound from this bobbin and measured in a suitable and customary manner.

Now it is important to produce the same length of yarn during production, since these - if not any influences that lead to falsifications - have to produce the same bobbin size. It is important to ensure that any production interruptions such as B. Eliminate thread breaks, take into account when determining the yarn length. For this reason, the yarn length generated is measured, which is done, for example, by measuring the revolutions of a take-off roller - taking into account its diameter - and - taking into account such production interruptions - the actual yarn length generated is calculated therefrom. Since the bobbin diameter depends on the thread thickness, this is determined from the diameter of the spun sliver and the distortion, ie the quotient of the sliver feed speed and the thread take-off speed. The bobbin diameter also depends on how tightly the bobbin is wound, ie on the winding tension, which is why this is also determined from the quotient of the winding speed and the take-off speed. Now the yarn thickness specified as the reference value and the winding tension specified as the reference value are compared with the corresponding measured values actually present below Compared values.

A correction value is then formed from the deviations that result, which is taken into account when determining the actual bobbin diameter and leads to an increase or decrease in the yarn length - in comparison to the reference yarn length - which corresponds to the determined bobbin diameter. It goes without saying that the computer which carried out the corresponding correction had previously been programmed accordingly - when entering the reference values - that the corrections lead to the correct end values. The correction values are to be determined empirically once and can then be entered in the same way for all machines.

In order to rule out inaccuracies, in particular in the production of conical coils, it is further expediently provided that, in the case of conical coils, a coil diameter based on a specific surface line is used as a reference.

It may be that after a long period of time the pressure roller of the pair of draw rollers runs in. The same applies to an even greater extent for the winding roller for driving the winding.

For this reason, it can be provided in a further advantageous embodiment of the method according to the invention that the actual yarn length for a certain bobbin diameter is checked at predetermined time intervals and the correction factor is corrected if the actual yarn length deviates from the theoretical yarn length to be expected taking into account the correction factor. In this way, the wear that has occurred in the meantime is taken into account from time to time, so that the spool size, despite wear, affects the diameter of the spool Drive elements can be kept constant within relatively small tolerances.

The measurements of the yarn length can in principle be carried out with any bobbin diameters, which is particularly useful when determining the reference values. When checking the coil diameter later, however, it is usually sufficient if the desired diameter of the full coil is selected as the specific coil diameter.

Since the twist of the yarn causes the yarn to become harder or softer, when the twist is mechanically given the twist - which e.g. in the case of rotor or frit spinning machines - in a further advantageous embodiment of the method according to the invention it is provided that the yarn twist is taken into account, for which purpose the twist of the yarn per unit length is determined from the quotient of the speed of the spinning element and the take-off speed and the deviation from a predetermined reference value is taken into account as a correction factor when determining the actual coil diameter. The predefined reference value has already been fed during the programming of the computer, so that a comparison with this known reference value is now possible. The measurement of the yarn twist can be carried out in addition to the determination of the yarn thickness, since - as said - the actual yarn thickness depends not insignificantly on the twist contained in the yarn.

In the case of spinning rotors, the speed of the spinning element is exactly the same as the number of rotations generated in the thread per unit of time. In the case of friction spinning elements, however, the diameter of which is a multiple of the diameter of a thread and the rotation of which occurs when the thread unrolls on the peripheral surface of at least one friction spinning element, on the other hand - based on the speed of the friction spinning element - a much higher speed is generated in the thread, which must be taken into account when determining the yarn twist per unit length. According to the invention it is therefore provided in devices in which the rotation is transmitted from the circumferential surface of the rotating spinning element to a thread rolling thereon that is being formed that the rotation transmission ratio between the spinning element and the thread is taken into account for determining the rotation of the thread per unit length.

In spinning processes in which the yarn twist is effected pneumatically, the yarn twist and thus the hardness of the yarn depends on the strength of the excess pressure which is brought to bear on the thread. This also applies to a pneumatic open-end spinning process, in which the individual fibers are integrated in a rotating yarn end, as well as to a pneumatic false-wire spinning process, in which a fiber ribbon is drawn into a fiber ribbon, incorrectly rotated and fixed in the wrongly rotated position by means of spread and integrated fiber ends becomes.

For pneumatic spinning processes it is therefore provided in a further advantageous embodiment of the subject matter of the invention that the overpressure which causes the yarn rotation and acts in the spinning element is measured and the deviation from a predetermined reference value is taken into account as a correction factor when determining the actual bobbin diameter.

However, the overpressure does not have a directly proportional effect on the yarn twist and thus on the hardness and thickness of the yarn. The size of the feed hole for the compressed air supplied to the spinning element, the position of these feed holes with respect to the central passage in the spinning element and their Inclination with respect to the longitudinal axis of the spinning element cause the overpressure in the spinning element to have a greater or lesser effect, so that the overpressure more or less influences the yarn thickness accordingly. This different intensity of influence of the overpressure due to different geometric modifications of the spinning element is taken into account according to the invention in that when the spinning element is replaced by one with a different geometry, the geometric deviations from a given geometry of the spinning element are taken into account as a correction factor in determining the actual spool diameter. The size of the correction factor is determined empirically beforehand and can then be entered directly if necessary without further attempts by providing appropriate markings at the entry point for the correction factor or by taking the corresponding value from a table and entering it as a numerical value.

Another factor that can affect the bobbin diameter is the properties of the fiber material that is spun. Natural fibers are usually much more elastic and fuller than synthetic fibers. Here, too, a reference value is formed when feeding the computer. Furthermore, according to the invention, it is later provided during production that fiber material properties which have an effect in the bobbin diameter are taken into account as a correction factor for determining the actual bobbin diameter.

Determining the current coil diameter is important for a wide variety of purposes. Advantageously, a signal for initiating a coil change is triggered, for example, as a function of reaching a predetermined coil diameter, taking the correction factors into account.

On the other hand, determining the bobbin diameter is also very important in connection with the removal of a broken thread. According to the invention, in connection with the elimination of a thread break, the determined bobbin diameter is fed to the drive of a thread take-up device as a signal parameter for determining an actuating value, and the thread take-up device is brought into a defined distance from the outer surface of the bobbin under construction.

The thread take-up device and its drive can also show signs of wear, which have an effect on the individual spinning positions as adjustment inaccuracies and thus also impair the thread take-up safety. According to the invention, it is therefore expediently provided that such a play occurring at the individual spinning positions and acting at a distance from the thread take-up device to the outer surface of the bobbin is taken into account as a correction factor.

Such play can change over time as a result of wear and thus also lead to a change in the delivery accuracy of the thread take-up device to the bobbin. In order to compensate for such changes in play, a further advantageous development of the method according to the invention provides that the play occurring at the individual spinning positions and acting at a distance from the thread take-up device to the lateral surface is checked at predetermined time intervals and the corresponding correction factor is corrected when this play changes.

In order to carry out the method according to the invention, in order to determine the current spool diameter of the tape feed device, the take-off device and the winding device, according to the invention a speed pick-up device which determines their speed of rotation is assigned, which is associated with a common control device are connected in terms of control, into which the yarn length corresponding to a specific bobbin diameter can be entered, which can be corrected in the form of correction factors which are calculated on the basis of the determined speeds of the tape feed device, take-off device and winding device.

In order to be able to take the yarn twist into account when determining the respective bobbin diameter, in a further advantageous embodiment of the device according to the invention, when the spinning element rotates for yarn production, the spinning element or its drive is assigned or deliverable a measuring element measuring its speed, which can be adjusted with the control device is connected for tax purposes in order to generate a correction factor.

It is not a requirement for the present invention that the spinning element rotates. The invention can also be used when the spinning element is of a non-rotating nature and in it an air vortex rotates for yarn production, which is kept rotating by a compressed air supply with a tangential component. This can be an open-end spinning element or just a spinning element in which a false twist is given to a fiber ribbon to form a thread. According to the invention, in such a case it is provided that the control element has at least one compressed air supply opening opening laterally into a thread formation zone from which the thread forming is drawn off and a compressed air line ending in this at least one compressed air supply opening or a compressed air source generating the compressed air Overpressure-determining signal transmitter is assigned, which is connected in terms of control to the control device for generating a correction factor.

The control device is preferably connected in terms of control to a bobbin changing device, so that an exchange of a full bobbin for an empty tube can be initiated when a predetermined bobbin size is reached.

Furthermore, it is advantageous if the control device is connected in terms of control to a drive for a thread take-up device, by means of which the latter can be brought into a defined distance from the respective outer surface of the bobbin under construction. Since a wide variety of correction values can be entered into the control device - in addition to the reference values - the thread take-up device can always be brought into an optimal position in relation to the bobbin under construction in order to take up the thread end required for re-spinning.

Since not all correction factors can be measured automatically, but partly have to be determined empirically, e.g. B. changing tolerances, the invention expediently provides that the control device is assigned an input device for the manual input of correction factors. The input device is advantageously subdivided into several partial input devices, one of which is used to input fiber material properties that affect the bobbin diameter and another is used to input a game at the respective spinning station that affects the delivery of the thread take-up device to the bobbin.

In order not to have to assign individual input devices to each spinning station, it is provided in a further advantageous embodiment of the subject matter of the invention that the control device has a separate memory for each spinning station, to which the input device can optionally be assigned.

“Correction factor” in the sense of the present invention is understood to mean any value that changes the values entered as the basic setting in the control device. It does not matter whether the theoretical yarn length, any play, wear in the transport and transmission elements, etc. Like. takes into account.

The bobbin diameter is required as a signal parameter for the control of both the bobbin change at the right time and for the control of a thread take-up device. In the following, the technical facts up to the determination of the coil diameter, i. H. until a corresponding signal parameter is obtained, which is ultimately used as an input parameter for controlling the above-mentioned processes.

As already stated above, the method according to the invention and the device according to the present invention enable a precise and precise determination of the current spool diameter in a simple and safe contactless manner and in adaptation to the most varied variables including different wear, which is essential for various tasks during the spinning process . So the spool change can be carried out exactly in time. In addition, even in the case of conical bobbins, the thread length required for piecing can be measured more precisely if the bobbin size is known than if it is not known. In addition, it is essential for the exact thread take-up from the bobbin that the bobbin size is known so that the thread take-up nozzle is set precisely in relation to the bobbin for the take-up in order to be able to bring the thread take-up nozzle as close as possible to the bobbin surface without the risk of bobbin damage .

The inventive solution can be used both in open-end spinning devices with mechanical and in fiber sliver spinning devices with pneumatic twist. It is not even necessary for the spinning device to be one that works on the open-end spinning principle, e.g. Rotor spinning, friction spinning or electrostatic spinning, but the invention can also be used in false wire spinning with pneumatic twisting.

The object of the invention can be realized in an economical manner since, as a rule, all driven elements have a central drive to which the rotary knives can be assigned. As a result, the subject of the invention can also be retrofitted inexpensively to existing machines with a large number of similar workplaces.

Figur 1:

Ablauf der Signalerfassung und -verarbeitung gemäß der Erfindung zur Ermittlung des Spulendurchmessers beim Rotorspinnen bzw. beim Spinnen mit pneumatischer Drallerteilung;

Figur 2:

einen schematischen Querschnitt durch eine erfindungsgemäß und ausgebildete Spinnstelle einer Rotorspinnmaschine;

Figur 3:

einen schematischen Querschnitt mit teilweiser Draufsicht durch eine erfindungsgemäß ausgebildete Spinnstelle einer Falschdraht-Spinnmaschine.

Embodiments of the invention are shown in the drawing. Show it:

Figure 1:

Sequence of signal acquisition and processing according to the invention for determining the coil diameter during rotor spinning or during spinning with pneumatic swirl assignment;

Figure 2:

a schematic cross section through an inventive and designed spinning station of a rotor spinning machine;

Figure 3:

a schematic cross section with a partial top view through an inventive spinning station of a false wire spinning machine.

Since the rotor spinning machine in particular has found its way into practice, a first exemplary embodiment of the subject matter of the invention is to be explained with the aid of an open-end spinning machine designed as a rotor spinning machine.

FIG. 2 shows a cross section through a work or spinning station of such a rotor spinning machine with only the essential elements that are absolutely necessary for understanding the invention; however, the other elements required for spinning or piecing have been omitted for the sake of clarity in the drawing.

The spinning device 1 of the rotor spinning machine has a feed device 2, a dissolving device 3 and a spinning element designed as a spinning rotor 4. Downstream of the spinning device 1 are a take-off device 5 and a winding device 6.

The feed device 2 has a driven feed roller 20 and a feed trough 21 which cooperates with it. A sliver B stored in a can 22 is fed to it. The feed roller 20, which usually extends over a plurality of spinning stations, is at a suitable location, e.g. in the drive end frame of the machine, a sensor 23 is assigned, which detects the speeds of the feed roller 20.

The opening device 3 has a opening roller 30 which is arranged in a housing 31, from which a fiber feed channel 40 extends into the spinning rotor 4, around the fibers F which come from the leading end of the sliver B fed to the rotating opening roller 30 through the feeding device 2 are combed out to feed the spinning rotor 4, where they are tied into the end of a thread G.

The thread G leaves the spinning rotor 4 arranged in a housing (not shown) through a thread draw-off tube 41, for which purpose it is continuously drawn out of the spinning rotor 4 by the draw-off device 5. The take-off device 5 consists in the usual way of a driven take-off roller 50, which extends over a large number of spinning positions, and one pressure roller 51 per spinning position.

The thread G is fed through the take-off device 5 to the winding device 6, which has a winding roller 60 which extends over a plurality of spinning positions and on which the forming bobbin 61, which is held rotatably between two swivel arms 62, rests for each spinning position. The winding device 6 has a traversing thread guide 63 for shifting the thread G.

Like the feed device 2, the spinning rotor 4, the take-off device 5 and the winding device 6 are each assigned a sensor 42, 52 or 64. The sensor 42 scans the spinning rotor 4 itself or its shaft 43 or its drive (e.g. support disks - not shown - which rotate in a fixed speed ratio to the spinning rotor 4). The sensors 52 and 64 sense the take-off roller 50 and winding roller 60, respectively, which extend over a plurality of spinning positions and are located at a suitable location, e.g. as well as the sensor 23, arranged in the drive end frame of the machine.

The sensors 23, 42, 52 and 64 are connected via lines 24, 44, 52 and 65 to a control device 7, which control various processes, such as, for example, the replacement of a full bobbin 61 for an empty tube or a piecing process after a machine stoppage or a thread break .

An input device 70 with several setting devices 71, 72 and 73 is connected to the control device 7 via a line 74, the meaning of which will be described in detail below.

• die Drehzahl der Speisewalze 20 (Sensor 23);
• die Rotordrehzahl (Sensor 42);
• die Drehzahl der Abzugswalze 50 (Sensor 52);
• die Drehzahl der Spulwalze 60 (Sensor 64).

On the OE spinning machine described, four different speeds are thus detected using conventional sensors 22, 42, 52 and 64. These are:

• the speed of the feed roller 20 (sensor 23);
• the rotor speed (sensor 42);
• the speed of the take-off roller 50 (sensor 52);
• the speed of the winding roller 60 (sensor 64).

Furthermore, the thickness of the incoming sliver B is determined by a sensor 25 for thickness measurement. The sensor 25 is connected to the control device 7 via a line 26.

Various constants that influence the coil size are manually entered via a keyboard or by means of rotatable adjusting knobs (input devices 71 to 74) of the input device 70. These include e.g. Material constants that influence the thread size. These material constants result from the diversity of the material to be processed, e.g. B. elasticity and strength of the cotton or plastic fibers. In connection with the signal detection, the signals coming in via the sensors 23, 25, 42, 52 and 64 are detected and sent for further processing.

There are three basic processing levels which, when combined, lead to the determination of the yarn length.

In a first level, the signal detection SE2 detects the number of the sliver B being fed (sensor 25), the speed of the feed roller 20 (sensor 23) and the speed of the take-off roller 50 (sensor 52).

The yarn strength can be determined as the product P from the number of the sliver B and the quotient of the feed roller speed to the speed of the take-off roller 50. The properties of different materials influencing the yarn strength (such as fiber thickness, among others) are known material parameters which are also taken into account as a signal parameter in the signal formation for the yarn strength . These material parameters are entered manually via a keyboard or another type of setting device 71 of the input device 70, for which purpose the memory has a separate memory for each spinning station, to which the input device 70 can be optionally assigned. For this purpose, for example, a numerical keyboard is provided, with the help of which the desired spinning position can be set.

The starting point for determining the winding tension, which is a measure of the winding hardness of the bobbin 61, is the rotational speed for the take-off roller 50 (sensor 52) and the rotational speed of the winding roller 60 (sensor 64). The signals obtained via the signal detection SE1 are processed into a quotient Q1 from the speed of the winding roller 60 to the speed of the take-off roller 50. The signal parameter SK1 for this quotient forms the wind-up voltage.

The starting point for determining the yarn twist is the detection of the rotor speed (sensor 42) and the speed of the take-off roller 50 (sensor 52) in the signal detection SE3. A signal parameter is determined by forming the quotient Q2 from the rotor speed to the speed of the take-off roller 50 SK3 determined, which represents the yarn twist.

When the OE spinning machine is started up for the first time, the signal parameters for yarn count SK2, winding tension SK1 and yarn twist SK3 are determined. In order to further minimize the influencing factors on these signals, appropriate correction values are determined. The correction values result from reference methods, by comparing the yarn strength, winding tension and yarn twist determined at any later point in time with the respective variables that were the basis for the initial start-up for the specific bobbin diameter, and deviations as correction factors for the yarn length when determining the actual coil diameter are used as a basis. The correction values of the winding tension KF1, the yarn thickness KF2 and the yarn twist KF3 obtained by reference methods are linked to determine the yarn length SK-GL. Taking into account possible production interruptions at a spinning station, the yarn length generated must be determined.

The signal parameter SK-GL for the yarn length is checked in the reference process with regard to the formation of a correction factor. When forming a correction factor for the yarn length KF-GL, this is taken into account in the subsequent determination of the bobbin diameter.

The bobbin diameter which can be corrected in this way is used as a signal parameter SK-SD for the control S of the bobbin change in due time or the control S of a thread take-up device 66 (FIG. 2) with respect to the bobbin surface, the bobbin target size for the bobbin change by the setting device 73 via a line 73 is entered.

Such a thread take-up device 66 is shown in broken lines in FIG. 2 and is usually used as a suction nozzle formed, which is arranged on a maintenance device which is movable along the spinning machine. The suction nozzle is pivotally mounted and can be pivoted from a rest position, in which it is pivoted away from the spool 61, into a working position in which its mouth is arranged at a predetermined distance from the circumferential surface of the spool 61, in order to after a thread break while simultaneously turning back the Bobbin 61 to suck the thread end located on the bobbin 61. If the distance is too large, the suction force acting on the bobbin surface is too weak to take up the thread G; on the other hand, if the distance is too small, the mouth of the suction nozzle will at least partially abut the layers of the spool 61, so that there is a risk that these layers or the wound thread G will be damaged or become damaged. The suction nozzle of the thread take-up device 66 is connected via a coupling housing 67 to a drive 68 which can bring the suction nozzle into a defined position with respect to the bobbin 61. For example, a drive and a slip clutch (not shown) are assigned to the drive 68, the stop being set by the control device 7 via a line 69 in accordance with the current coil size. For this purpose, the suction nozzle is also movably mounted at its end facing the suction air source via a pivotable intermediate tube piece.

If a game is detected at a constant distance during the positioning of the thread take-up device 66 by means of checks carried out from time to time against the bobbin surface, this game can be done in the distance positioning by manually entering a correction value via the keyboard (setting device 72, line 74a) directly opposite the control Getting corrected.

The method and / or the device can be modified in a variety of ways within the scope of the present invention by exchanging individual characteristics with equivalents or with other combinations. For example, it is possible to distribute the setting device 71, 72 and 73 to different input devices 70 which are arranged at different locations and / or are formed differently from one another. The input devices can also be designed for the input of digitally selectable numbers or as rotary knobs for the input of analog values.

As already stated above, the invention is not limited to spinning machines with mechanical twist distribution. Rather, it can be used on all spinning machines on which a sliver B is spun into a thread G. Such a spinning machine is e.g. also a wrapping spinning machine, on which a core yarn is produced, around which a wrapping yarn is looped. It goes without saying that the strength of the wrapping yarn, the number of wraps per unit length and the tension with which the wrapping thread is wrapped around the core yarn must be taken into account. Appropriate sensors and / or setting devices must be provided for this.

If the spinning element, for example a spinning rotor 4, receives rotation, which it then passes on to the thread G which is being produced, then the yarn rotation can be determined very easily directly from the speed of the spinning element. In the case of a spinning rotor 4, the number of rotations is predetermined directly by the rotor speed. In the case of a friction spinning element, the ratio between the diameter of the driven friction spinning element and the thread G must be taken into account when calculating the yarn twist. In such a case, the diameter ratio in question must also be taken into account when calculating the quotient from the speed of the spinning element and the take-off speed. With others Expressed in words, this means that the rotation transmission ratio must be taken into account for the transmission of twist from the circumference of the spinning element to the thread rolling on it, which is being formed, for the determination of the yarn twist per unit length.

As already mentioned above, the method can also be used in spinning machines, in which the thread is twisted in a pneumatic way. Such a spinning device is shown in FIG. 3. Serving as a feeding device 8 here is a drafting system which, with its pairs of rollers 80, 81 and 82, warps the sliver B fed into a sliver which is spun into a thread G in the spinning element 9.

In the exemplary embodiment shown, the spinning element 9 consists of a first nozzle, an injector nozzle 90, and a swirl nozzle 92 arranged downstream of it, leaving a gap 91. The injector nozzle 90 and the swirl nozzle 92 each have compressed air supply openings 900 and 920, respectively, of which the injector nozzle 90 or the annular duct 901 or 921 surrounding the swirl nozzle 92 and open substantially tangentially with the axial component in the axial bores 902 or 922 of the injector nozzle 90 or the swirl nozzle 92. The two ring channels 901 and 921 are above two.

Lines 903 and 923 with a common line 93 and via this with a common pressure source 94 in connection. A manometer 95 is connected to the line 93 and is connected to the control device 7 for control purposes via a line 96.

Two sensors 83 and 85 are also connected to the control device 7 via lines 84 and 86, each of which has a roller at the outlet or at the inlet of the drafting system Scan the 8 pairs of rollers 82 or 80 located. Furthermore, sensors 25, 52 and 64 are connected via lines 26, 53 and 65, which - as explained using the example in FIG. 2 - scan the fiber sliver B, the take-off roller 50 and the winding roller 60.

An input device 70 is also in control connection with the control device 7 via lines 74, 74a, 74b, 74c, which has an adjusting device 71 (line 74b) for adjusting the processed material, an adjusting device 72 (line 74a) for adjusting a correction factor for the Mechanism of the thread take-up device 66 (see FIG. 2) influences wear, an adjusting device 73 (line 74) for setting the desired desired bobbin diameter for the full bobbin 61 and an adjusting device 76 (line 74c) for setting a correction factor to take into account the geometry of the the injector nozzle 90 and the swirl nozzle 92 existing spinning element 9.

The manometer 92 measures the overpressure that prevails in the line 93 and is therefore present in the compressed air supply opening 900 or 920, which opens laterally into the thread formation zone. In the device described, the thread formation zone is formed by the two axial bores 902 and 922 of the injector nozzle 90 and the swirl nozzle 92. The manometer 95 thus detects the excess pressure applied to the spinning element 9 and emits a corresponding signal to the control device 7. This signal transmitter (manometer 95), which determines the level of the effective overpressure, can - as shown - be assigned directly to the line 93 or the overpressure source 94.

For the determination of the actual coil diameter, the control device 7 continuously - apart from the signals coming from the sensors 25, 85, 83, 52 and 64 - from the manometer 95 signals are supplied, which are compared with a value registered in the control device 7 as a reference value. If the signal from the manometer 95 deviates from the target value, a corresponding correction factor is formed to correct the value for the coil diameter.

The distortion of the fiber sliver B is calculated from the signals coming from the sensors 85 and 83 and can be corrected by the signal coming from the sensor 52.

The reference values, for the setting of which only the setting device 73 is shown in the input device 70, are all set in the input device 70 by means of additional setting devices, wherein the input device 70 or a part thereof can be an integral part of the control device 7.

If the spinning element 9 is replaced - either completely or only the injector nozzle 90 or the swirl nozzle 92 - with a spinning element of a different geometry with regard to the dimensioning and / or arrangement or orientation of the compressed air supply openings 900 and / or 920, the effect of the compressed air on the naturally also changes Thread G, and there is a different twist. This must be taken into account when calculating the bobbin size, since this changes the yarn hardness and thus the yarn cross-section.

Through experiments, this influence is thus determined for each spinning element 9 in question and recorded in the form of a correction factor, which can either be stored in the control device 7 for later retrieval by means of the setting device 76 or entered in a table which it can be input as required can be removed into the input device 80 (setting device 76).

In the case of conical coils 61, the value of a specific surface line is used as the reference value. In principle, any surface line can be used for this, but it has proven expedient to select the diameter of the length range as the reference, on which the drive takes place, for coils 61 which are driven via their outer circumference.

Since the rollers conveying the fiber material or the rollers driving them are subject to wear, deviations occur over time between the desired nominal value for the coil diameter and the actual coil diameter. In order to keep these deviations within acceptable limits, it is checked from time to time, preferably at predetermined time intervals, whether deviations occur and how large they are. If necessary, a correction factor is to be entered by means of an adjusting device (not shown) of the input device 70.

In principle, any coil diameter is suitable for the definition of setpoints. However, since the scatter is smaller when a longer yarn length is selected, it is particularly expedient to use the full bobbin 61 to determine the bobbin size to be assigned to a specific yarn length.

Claims (21)

1. Process for determining the diameter of a bobbin (61) at a spinning point (1, 9) of a spinning machine, in which spinning machine a sliver (B) of known thickness is supplied to the spinning point (1, 9) at a certain speed, is spun into a thread there and is then drawn off from there at a draw-off speed which is in a defined ratio to the sliver supply speed and is wound onto the bobbin (61) at a wind-on speed matched to the draw-off speed, characterized in that

   - the yarn length corresponding to a certain bobbin diameter is determined empirically under predetermined conditions (yarn thickness, wind-on tension),

   - the yarn length produced is measured taking into account possible interruptions in production at this spinning point (1, 9),

   - the yarn thickness is determined from the product of the sliver thickness and the quotient of sliver supply speed and thread draw-off speed,

   - in that a parameter for wind-on tension is determined from the quotient of the wind-on speed and the draw-off speed,

   - in that subsequently the determined yarn thickness and the determined wind-on tension are compared with the yarn thickness and the wind-on tension which formed the basis of the empirical yarn length determination for the certain bobbin diameter and any deviation which is produced forms the basis as the correction factor (KF1, KF2, KF3) for the yarn length in determining the actual bobbin diameter.
2. Process according to Claim 1, characterized in that in the case of conical bobbins a bobbin diameter related to a certain generatrix forms the basis as a reference.
3. Process according to Claim 1 or 2, characterized in that at predetermined intervals in time the actual yarn length for a certain bobbin diameter is checked and in the event of a deviation of the actual yarn length from the theoretical yarn length to be expected, taking into account the correction factor (KF1, KF2, KF3), the correction factor (KF1, KF2, KF3) is corrected.
4. Process according to one or more of Claims 1 to 3, characterized in that the desired diameter of the bobbin (61) once it is full is chosen as the given bobbin diameter.
5. Process according to one or more of Claims 1 to 4, characterized in that the rotation of the yarn per unit of length is determined from the quotient of speed of the spinning element and draw-off speed and the deviation from a predetermined reference value is taken into account as a correction factor in determining the actual bobbin diameter.
6. Process according to Claim 5, characterized in that in the transmission of rotation from the periphery of the rotating spinning element to the thread which rolls thereon and is being formed the ratio of transmission of rotation between the spinning element and thread is taken into account for determining the rotation of the thread per unit of length.
7. Process according to one or more of Claims 1 to 4, in which the rotation of the yarn is produced pneumatically, characterized in that the excess pressure which brings about rotation of the yarn and acts in the spinning element (1, 9) is measured and the deviation from a predetermined reference value is taken into account as a correction factor in determining the actual bobbin diameter.
8. Process according to Claim 7, characterized in that when the spinning element (1, 9) is replaced by another of a different geometry the geometrical deviation from a predetermined geometry of the spinning element (1, 9) is taken into account as a correction factor (KF1, KF2, KF3) in determining the actual bobbin diameter.
9. Process according to one or more of Claims 1 to 8, characterized in that fibre material properties having an effect on the bobbin diameter are taken into account as a correction factor for determining the actual bobbin diameter.
10. Process according to one or more of Claims 1 to 9, characterized in that a signal for the initiation of a bobbin change is triggered in dependence on reaching a predetermined bobbin diameter determined by taking into account the correction factors (KF1, KF2, KF3).
11. Process according to one or more of Claims 1 to 10, characterized in that to eliminate a thread breakage the determined bobbin diameter is supplied to the drive of a thread-receiving apparatus as a signal parameter for determining an adjustment value and the thread-receiving apparatus is brought to a defined spacing from the outer surface of the bobbin being constructed.
12. Process according to Claim 11, characterized in that play which occurs at the individual spinning points (1, 9) and which acts in the spacing between the thread-receiving apparatus (6) and the outer surface of the bobbin is taken into account as a correction factor (KF1, KF2, KF3).
13. Process according to Claim 11 or 12, characterized in that the play which occurs at the individual spinning points (1, 9) and which acts in the spacing between the thread-receiving apparatus (6) and the outer surface is checked at predetermined intervals in time and in the event of an alteration in this play the appropriate correction factor (KF1, KF2, KF3) is corrected.
14. Apparatus for determining the diameter of a bobbin (61) at a spinning point (1, 9) of a spinning machine, having a respective spinning element, a respective controllable sliver-supply apparatus (2, 8) for supplying a sliver (B), a respective controllable draw-off apparatus (5) and a respective controllable wind-on apparatus (6) for each spinning point (1, 9), for carrying out the process according to one or more of Claims 1 to 13, characterized in that there is associated with the sliver-supply apparatus (2, 8), the draw-off apparatus (5) and the wind-on apparatus (6) respectively a speed pick-up apparatus (23, 85, 83, 52, 64) which determines the speed of rotation thereof and which is in control connection with a common control apparatus (7) into which there can be input the yarn length which corresponds to a certain bobbin diameter and which is correctable in the form of correction factors which are calculated on the basis of the determined speeds of sliver-supply apparatus (2, 8), draw-off apparatus (5) and wind-on apparatus (6).
15. Apparatus according to Claim 14, characterized in that there is associated with or can be advanced to the spinning element (4, 3) or its drive a measuring element (42) which measures the speed thereof and is in control connection with the control apparatus (7) for producing a correction factor.
16. Apparatus according to Claim 14, characterized in that the spinning element (9) has at least one compressed-air supply opening (900, 920) which opens laterally into a thread-forming zone from which the thread (G) being formed is drawn off axially and there is associated with a compressed-air line (93) ending in this at least one compressed-air supply opening (900, 920) or with a compressed-air source (94) producing the compressed air a signal transmitter (95) which establishes the level of the excess pressure and is in control connection with the control apparatus (7) for producing a correction factor.
17. Apparatus according to one or more of Claims 14 to 16, characterized in that the control apparatus (7) is in control connection with a bobbin-changing apparatus.
18. Apparatus according to one or more of Claims 14 to 17, characterized in that the control apparatus (7) is in control connection with a drive (68) for a thread-receiving apparatus (66), and as a result of this drive (68) the thread-receiving apparatus (66) can be brought to a defined spacing from the respective outer surface of the bobbin (61) being constructed.
19. Apparatus according to one or more of Claims 14 to 18, characterized in that an input apparatus (70) for manually inputting correction factors is associated with the control apparatus (7).
20. Apparatus according to Claim 19, characterized in that the input apparatus (70) is divided into a plurality of part input apparatus items, of which one serves to input fibre material properties having an effect on the bobbin diameter and another serves to input a play at the respective spinning point which has an effect on the advancing of a thread-receiving apparatus (66) to the bobbin (61).
21. Apparatus according to one or more of Claims 14 to 20, characterized in that the control apparatus (7) has for each spinning point in each case a separate store with which the input apparatus (70) can in each case selectively be associated.

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