Title of Invention

A METHOD FOR CONTROLLING A RING SPINNING FRAME

Abstract

For controlling a spinning frame with a drafting unit 12, spindles 6 and a ring rail 20 and with a clamping device 28 for the yarn 10 in a position below a cop 8, starting from the point of the formation of a reverse winding, the twist and/or draft and the number of revolutions are being changed in such a way, in that adapted i.e. higher or lower strength proportions or characteristics respectively, of the yarn result within the section of the reverse winding or underwinding. Thus the operating reliability of the spinning frame is increased, in particular in that unwanted thread breaks are avoided or in that desired thread breaks are being obtained.

Full Text

Ring spinning frame with clamping device at the spindle The present invention relates to a spinning frame according to the preamble of the independent device claim and to a method according to the first independent claim. A spinning frame of this type is know from the European patent EP 0 462 467. The clamping device below the cop at the spindle enables to operate with a comparatively short length of yarn for the underwinding. It is the aim to operate with an underwinding yarn length (clamping length) corresponding with a partial loop of the spindle at the height of the underwinding crown or the clamping device respectively. In order to reach this target it is necessary the determine the wound yarn length as exactly as possible, for which reason the supply quantity of yarn from the drafting unit is measured starting from the point of time, at which the ring rail with the traveller has laid the yarn at a height below the upper edge of the underwinding crown. Such a device is being described in detail in the European patent EP 0 528 752. The objects of the two mentioned European patents are thus considered as an integrated part of the invention being described hereafter. From the European patent 0 480 357 it is known to control the number of revolution of the spindles or of the drafting unit respectively individually, during the spinning out process, where, however the particular problem of the underwinding with a clamping device is not being considered. In ring spinning frames according to the known art, which are provided with electromotive drives for a fast lowering of the ring rail, the ring rail is basically moved downward at constant speed for the formation of the reverse winding. In a ring spinning frame of the present type with a clamping device for the yarn in the underwinding position, the individual operating parameters have to be adapted to one another more exactly than in today's conventional spinning frames. It may be necessary to specifically influence the yarn characteristics, especially during the last phase of the spin out, in order to assure an operation without disturbances. These are requirements to be met with the present invention. To solve the task a spinning frame with a drafting unit, a spindle and a ring rail, whereat the drafting unit, the spindle and the ring rail are being kept in coordinated operation via the respective drives, and with a clamping device for the yarn in a position below the cop on the spindle, whereat during the formation of the reverse winding, when the yarn is led from the uppermost position on the cop, into the position below the cop to the clamping device, the individual components of the drafting unit drive and of the spindle drive are being driven in such a way, that before the lower part of the cop is reached, within the second phase of the downward movement of the ring rail, the twist of the yarn is specifically being altered, in order to achieve a higher strength, before the yarn is being brought into the section of the clamping device and the spinning frame is being decelerated to a standstill. The ring rail then remains only during approximately two revolutions of the spindle in the lowest position at the clamping device, preferably, however only as long until the yarn has been laid over half, up to three quarters of the circumferential length within the winding zone. During the downward movement of the ring rail the supply speed in the drafting unit and the number of revolutions of the spindle are being reduced in such a coordinated way, that the desired yarn twist and yarn count is at first maintained and that the yarn course on the cops becomes rather steep. However, a change in yarn count can also be of advantage. After depositing the underwinding the ring rail is again lifted up from the lowest position into the position above the clamping device, whereafter first the drafting unit and then the spindle drive or both at the same time are brought to a standstill. After formation of the underwinding the drafting unit can still be kept in operation for a short period of time, in order to further supply a yarn length which is additionally required because of a deflection of the yarn below the drafting unit due to the upward tilting of the yarn guide. On the other hand, during a fast downward movement of the ring rail and when at the same time the reverse winding is being laid, no yarn curlings may form due to low yarn tensions within the yarn section between the drafting unit and the traveller, and on the other hand the yarn tensions may not exceed a permissible value. The spindle drive, the ring rail drive and the drafting unit drive are linked with a control unit. The control unit comprises besides the power section a memory, an input unit and a data processor. In the data processor, operating programmes for the different drives are stored. On the other hand programme modules for the single drives may be provided in the the control unit. Further an input device pertains to the control unit and a memory for the entered textile technological data. Above the clamping device, being shiftable along the spindle, an underwinding crown or a cutting ring respectively, is fixedly attached to the spindle, whereat the arrangement is made in such a way, that in the clamping position for the yarn, the clamping device rests on the underwinding crown. The clamping device is being pressed upwards by a spring from the lower part of the spindle and by means of a separate actuating device or directly by the ring rail during its movement the clamping device can be shifted into the lowest downward position, that is into the opening position. The indications for direction relate to the schematic illustration in figure 2, whereat said indications for directions are not absolute but are being chosen from the viewpoint of the observer. There are textile technological data being entered into the input unit, such as the twist of the yarn, the mass of the cop, the cop diameter, the length of the sleeve and the ring diameter; furthermore maximum deceleration values for the spindle and for instance maximal values for the ring rail speed during the downward movement within the last phase can be defined. With the help of the data processor the operating programmes for the drafting unit drive, the spindle drive and the ring rail drive are then calculated or stored in the memory respectively, especially also the desired altered yarn characteristics during the last phase of the spin out. Depending on the yarn to be produced, different parameters result for the calculation of the operating programmes, which can be stored as data sets in the memory. The control unit calculates the data of the operating programme in a way, that due to the observation of the textile technological boundary values, during the last phase of cop formation, as few thread breaks as possible occur, that is during doffing or cop exchange respectively, and during the start of newly spinning of a cop. Due to the clamping of the yarn below the cop, when an additional need of thread length arises, the traveller on the ring of the ring rail cannot be turned backward, therefore it can be important, that the drafting unit still supplies an additional yarn length, after the yarn is already blocked in the clamping device. With this arrangement an unthreading of the yarn from the traveller is practically impossible. While the reverse winding is performed on the cop, the deceleration of the number of revolutions of the spindle occurs with a delay value of preferably between 15 and 25 1/s2. If the yarn count is also to be maintained during this last phase of cop formation, then due to the yarn count and the yarn twist, the drafting unit deceleration has to be calculated depending on the delay in the spindle drive. The ring rail speed in consequence is to be adapted to the supply speed of the yarn, so that the yarn supply during winding of the reverse winding is just sufficient. Besides a calculation of the operating programme for the drafting unit and the ring rail, single values for the supply quantity of the yarn from the drafting unit and the lifting height of the ring rail in dependence on the numbers of revolutions on the spindle can be determined experimentally. Depending on yarn count, a ring rail speed of between 30 and 120 mm/sec is being preferred, where the first value stands for a fine yarn count and the second for coarse yarns. It can also be of advantage to alter the yarn count starting at least from the point of time of performing the reverse winding in a way that a favourable condition results for inserting the yarn into the clamping device. In the following the invention is being described in detail by way of the drawing, wherein shows: Figure 1, a diagram in which the number of revolutions of the spindle N (1/min), the supply L (m/min) from the drafting unit and the ring rail stroke H (m) are listed. Figure 2, a schematic illustration of a spinning unit of the spinning frame. Figure 3, a diagram with the dependence of the yarn strength H from the torsion coefficient a. After completion of the cop 8, it is possible, if desired, that within its upper part first a so called upper winding, thereafter, during lowering of the ring rail 20 the reverse winding and finally the underwinding below the cop is laid onto the spindle 6, whereafter the so called doffing i.e. the removal of the cop or of a number of cops respectively, takes place in the spinning frame. This phase, starting with the reverse winding is considered to be critical, since during transition from normal spinning operation to the standstill of the machine before the doffing and before the following start of the spinning frame, most of the thread breaks or disturbances respectively can occur, such as unthreading of the yarn 10 from the traveller 18, that is, if no optimal conditions prevail. During a fast reduction of the number of revolutions of the spindle N, during the last phase of the cop travel, the thread balloon, which forms between a thread guide 14 and the traveller 18 around the cop 8, has the tendency to collapse at the loss of tension, since the centrifugal force on the yarn is declining. This has to be compensated for by reducing the supply L from the drafting unit 12 and at the same time by a suitable downward movement of the ring rail. It has been recognised, that at the beginning of the formation of the reverse winding, that is starting from the point of time TO, the ring rail has to be moved downward fast according to figure 1, whereat, however the movement has to be decelerated again in order to avoid excess tensioning in the yarn 10. The movement of the ring rail in the first phase of the reverse winding between the point of time TO and T1 is thus characterised by a fast downward acceleration of the ring rail 20 followed by a deceleration. As soon as the ring rail 20 with the traveller 18 and the yarn 10, however, are being located within the section of the lower part of the cop 8a, it is suitable to increase the lowering speed of the ring rail 20 again, so that the yarn is being led as steep as possible along the circumference of the cop 8 or of the bottom part of the cop 8a respectively, down to an underwinding crown 26. Preferably the value of the angle of the yarn along the circumference of the cop 8a may not fall below 45° in relation to a horizontal line. Thus it is assured that the yarn 10 at the point of time T2 is positioned precisely at the outer rim of the underwinding crown 26 which is toothed and thus the tendency for gliding along the underwinding crown during further rotation of the spindle 6 is being avoided. The ring rail remains only for a short period of time between T2 and T3 below the underwinding crown. During this period the clamping device 28 is positioned next to the double arrow in figure 2, in a position away from the underwinding crown 26, preferably due to the fact that the lower part of the ring rail rests on the clamping device 28, which, by the force of a spring from below, can be shifted along the spindle shaft of the spindle 6. It is assumed that at the point of time T2, the clamping device 28 begins to move away from the underwinding crown 26 and that at the point of time T3 it rests again on it. By this process the yarn 10 is being clamped between the underwinding crown 26 and the clamping device 28, so that a relatively short piece of yarn, called underwinding or length of clamping yarn suffices to ensure a secure holding and a precise yarn rupture at the height of the underwinding crown 26 during the succeeding doffing, i.e. the removal of the cop. The underwinding length is preferably shorter than a circumferential length on the spindle 6 below the underwinding crown 26. While on one side of the underwinding the yarn 10 breaks during the removal of the cop 8, on the other side the connection with the yarn 10 leading through the traveller 18 upwards through the yarn guide 14 up to the drafting unit, stays intact. After replacing a new empty sleeve 30 on the spindle 6 the spinning process can then start again. From figure 1 can be seen, that also after the point of time T3 still a finite yarn supply L takes place up to the point of time T4. The herewith delivered so called excess length, being required in order to provide an additional length within the course of the yarn guidance between the drafting unit 12 and the traveller 18 on a spinning ring at the ring rail 20, which is required when the yarn guide 14, according to the arrow at 14 is being swung upwards before the doffing process. Furthermore from figure 1 can be seen, that the spindle at the point of time T4 of the supply stop, can still be rotated up to the point of time T5, whereby the yarn 10 receives a higher twist than during the normal spinning process. Said excess twist can be of advantage since the yarn during the next critical phase of the start of the spinning process is being exposed to a higher tension than during the regular spinning process. According to the invention, from a certain point of time on, for instance T1, according to figure 1, or still before the point of time TO, when the reverse winding is not being carried out yet, the twist (corresponding with the torsion coefficient a) is changed in such a way, that within the section of the clamping crown or underwinding crown 26 favourable conditions result for inserting, clamping or tearing of the yarn during doffing of the cop. If for instance a yarn is to be produced with the torsion coefficient a' it can be favourable to increase the twist to a" or to decrease it so that the breaking load B reaches its most favourable value for the stopping and the following starting of the spinning frame. Furthermore, for a disturbance-free insertion of the yarn, below the underwinding crown and the removal of the cop, whereby a yarn rupture occurs, it can be preferable to alter the supply of the drafting unit in such a way, that a yarn of a different count results. Especially, it is to be aimed at to increase the yarn count, that is to reduce the cross section during or (shortly) before underwinding, to make the yarn more smoothly whereby less disturbances result before, during and after the underwinding. During the following re-winding of the yarn in the winding machine, the concerned yarn part is then removed automatically, so that the changed yarn structure has no negative effect in the succeeding processes. For the co-ordinated movement of the ring rail 20, of the spindle 6 and the rollers in the drafting unit 12, the respective drives such as the drafting unit drive 12a, the ring rail drive 16 and the spindle drive 22, as illustrated in figure 2, are being connected to a control unit 24, which comprises a power section 24a, a memory 24b and an input unit 24c. Further a data processor 24d is being provided in order to determine the motion programmes, amongst other things, for the spindles 6, the drafting unit 20 and the movement of the ring rail 20. Preferably a calculating programme is loaded into the data processor 24d, which, based on the input value, as the lengths of sleeve HL, the diameter of the spinning ring D, the number of reverse windings HW, the clamping length, that is the underwinding length of the yarn 10 UW and the supplemental length ZL, supplied between the points of time T3 and T4, and finally the torsion coefficient a, calculates the optimal laws of motion. Preferably a deceleration value of above 15 1/sec2 for slowing down of the spindle drive 22 is preset. When calculating the ring rail speed, a dependence prevails from the supply L, so that during formation of the reverse winding the yarn is not excessively elongated or relaxed. The yarn supply starting from the point of time TO, according to figure 1, is the yarn length for the reverse winding, for the underwinding and the supplemental length, the latter between the points of time T3 and T4. The supply L for the yarn is calculated on the base of the preset function N = f(t) with the mentioned deceleration value and the torsion coefficient a, where the conditions [T/m = αm .VNm = N/L] is to be met, with T number of revolutions m unit of length am torsion coefficient Nm yarn count N number of revolutions of the spindle in revolutions per minute r.p.m. L supply in meters per minute It is also possible to set course of the supply L above the time and calculate the number of revolutions N accordingly. Since during the production of a specific yarn, whose characteristics regarding the underwinding cannot be determined in advance, it is suitable to lay out the control unit 24 in such a way, that in deviation to the theoretically calculated number of revolutions N of the spindle above the time, the operation is is being performed with a reduced number of revolutions N (t), with the aim, that the spindles come to a standstill after completion of the underwinding, that is at the same time with the drafting unit or only slightly later, i.e. by one second later at a maximum. Thus jamming of the traveller with the ring is being prevented, which could be the case if the spindles were rotating too long after the stop of supply from the drafting unit. Thus more favourable conditions are also being provided for the succeeding restart of the spinning frame when immediately after switching on of the spindles, the travellers continue to rotate. The control unit 24 is preferably to be laid out in such a way, that the spindles prior to the actual switching on of the spinning frame, starting with a gradual acceleration up to the operating speed, the movement of the ring rail and the start-up of the drafting unit are being rotated forward by a fraction of one revolution or several revolutions, so that the travellers can be freed from a possible unfavourable jammed position. Depending on the material to be processed in the spinning frame, the mode of this advanced rotation of the spindles, should possibly be selectable between an on and off position. In particular when applying so called T-flange spinning rings it can be of advantage to control the spindles 6 in such a way that they come to a standstill in the position of the upper ring side on the ring rail 20 at the height of the underwinding crown. When influencing the yarn twist in such a sense, that an optimal yarn strength results during the reverse winding or at least during the underwinding respectively, then for instance for knit yarn an additional twist is imparted, while on the other hand for instance for crepe yarn the yarn twist is reduced. When producing effect yarn, for instance flame or knop yarn, it is suitable to keep the number of revolutions of the drafting unit 12 or the supply respectively, constant that is starting from the beginning of the reverse winding or at the latest with the beginning of the underwinding, so that during this phase of the spin out process, smooth yarn without effects results. Thus a higher operation reliability is achieved since for the underwinding and the following tearing off of the yarn during cop change the desired yarn strength can be achieved. If a so called flame or a thick part were present within the section of the underwinding of the yarn, or before or after said section, then the yarn could break at this point during the cop change or doffing respectively, and not at the planned point where the reverse winding part contacts the clamping crown below the cop. By switching off the effect control for the reason of the change of the number of revolutions in the drafting unit, then a collapse of the balloon during the spin out can also be avoided. The subpression of the effect control of the yarn can be realised in a simple manner in that within the control unit 24 especially for the drafting unit drive 12a, a frequency threshold is being determined, below which frequency no flames are being produced anymore. By means of a potential free contact the flame effect can be switched on or off respectively. In the memory 24b or by means of the input unit 24c respesctively, calculating parameters can be retrieved or entered respectively, to effect within the data processor 24d that a variation of the number of revolutions in the drafting unit 12 during the reverse winding is subpressed. According to figure 2 an impulse generator 12b may be arranged on the drafting unit drive 12a, preferably on the outlet roller of the drafting unit 12, and a rotary inducer 16a on the ring rail drive 16, each of which is connected to the control unit 24. Based on the impulses of the impulse generator 12b, which in corresponcence to the yarn supply are being transmitted to the data processor 24d, the ring rail speed can be calculated continuously if there are no pre-calculated operating programmes being stored within the memory 24b. The impulse generator 16a, laid out as an absolute value transducer, enables the determination of the point of time at which, after passing the underwinding crown, the yarn is to be laid as underwinding, so that starting from this point of time, the supply length of the yarn during the formation of the underwinding can exactly be determined by the rotary generator 12b. A comparator 24e of the control unit 24, in which the pre-set values from the memory 24b and the actual values from the distance transducers 12b and 16a are being compared, triggers within the power section switching conditions for the drafting unit drive 12a or in the ring rail drive. In a module of the memory 24b laws of motion are being stored for the acceleration process and the deceleration process of the ring rail drive, which, depending on the signals for the rotary generator 16a can be retrieved from the data processor 24d. The ring rail drive 16 is controlled in such a way, that the ring rail 20 remains in the lowest position during a maximum of two loops around the spindle 6 by the yarn within the section of the underwinding, preferably, only during ¾ loops. The number of revolutions of the spindle during the formation of the reverse winding is decreased in such a way, that the number of revolutions of the spindle at the beginning of the formation of the underwinding amounts 6'000 revolutions per minute at the most As long as the ring rail 20 remains in the lowest position during the underwinding, the spindle 6 rotates at less than 1'000 revolutions. The underwinding yarn length being wound onto the circumference of the spindle preferably amounts to less than 100 mm. The lowering speed of the ring rail 20 during the formation of the reverse winding, that is between the uppermost position on the spindle 6 and the lowest position, is chosen in relation to the supply from the drafting unit 12 and to the number of revolutions of the spindle 6 in such a way, that the yarn 10 being led steeply downward, amounts to between 0.5 and 3 loops on the cop. The inclination of the yarn 10 is as far as possible to be kept constant. Thus, during the formation of the reverse winding at the end of the winding of a cop before the lower part of the cop is reached within the last phase of the downward movement of the ring rail 20, the twist a of the yarn is being changed specifically in order to achieve an adapted strength, before the yarn is brought into the section of the clamping device 28 and before the spinning frame is being decelerated down to the standstill. For controlling a spinning frame with a drafting unit 12, spindles 6 and a ring rail 20 and with a clamping device 28 for the yarn 10 in a position below a cop 8, starting from the point of the formation of a reverse winding, the twist and/or draft and the number of revolutions are being changed in such a way, in that in comparison to the normal spinning process adapted i.e. higher or lower strength properties or characteristics respectively, of the yarn result within the section of the reverse winding or underwinding. Thus the operating reliability of the spinning frame is increased, in particular in that unwanted thread breaks are avoided or in that desired thread breaks are being obtained. 1. Method for controlling a ring spinning frame with a drafting unit (12), a spindle (6) and a ring rail (20) where the drafting unit (12), the spindle (6) and the ring rail (20) are being kept in co-ordinated operation via the respective drives (12a,22,16) by means of a control unit (24), and with a clamping device (28) for the yarn (10) in a position below a cop (8) on the spindle (6) characterised in that during formation of the reverse winding at the end of the winding of a cop before reaching the cop bottom part within the last phase of the downward movement of the ring rail (20), the twisting ( 2. Method for controlling a ring spinning frame with a drafting unit (12), a spindle (6) and a ring rail (20), whereat the drafting unit (12), the spindle (6) and the ring rail (20) are being kept in co-ordinated operation via the respective drives (12a, 22,16) by means of a control unit (24), and with a clamping device (28) for the yarn (10) in a position below a cop (8) on the spindle (6) characterised in that during formation of the reverse winding, while the yarn (10) is being led from the top position on the cop, that is to the position below the cop to the clamping device (28), a change in the yarn count is caused, in particular during the production of relatively coarse yarns, the drafting unit (12) is being influenced in such a way that a finer yarn count results. 3. Method according to one of the preceding claims, characterised in that the drafting unit (12) is being controlled in such a way, that for the presented fibre material a higher amount of drafting is obtained, in particular by increasing the number of revolutions of the input rollers or output rollers respectively, of the drafting unit (12). 4. Method according to one of the preceding claims, characterised in that after forming of the underwinding on the spindle (6) the ring rail (20) is again lifted into the position above the clamping device (28), whereafter first the drafting unit (12) or the drafting unit drives (12a) respectively, and then the spindle drive (6) or both at the same time come to a standstill. 5. Method according to one of the preceding claims, characterised in that the clamping device (28) can be pressed upwards by a spring from the lower part of the spindle (6) and by means of a separate actuating device or directly by the ring rail (20) during its movement into the lowest downward position, that is into the opening position shiftable. 6. Method according to one of the preceding claims, characterised in that from a specific point of time (T1 ,T0) the twist of the yarn or the torsion coefficient a respectively, can be changed in such a way, that within the zone of the clamping device (28) and the underwinding crown (26) the most favourable conditions result for the inserting, the clamping, or the tearing of the yarn during doffing of the cops. 7. Method according to one of the preceding claims, characterised in that during production of a yarn with a given yarn count with a torsion coefficient a' the twist is being increased or decreased respectively, in such a way to another torsion coefficient a", by which the breaking load of the yarn reaches the most favourable value. 8. Method according to one of the preceding claims, characterised in that the supply of the drafting unit (12) during production of the reverse winding is changed in such a way, that a yarn of a changed, in particular of a finer count results, so that less disturbances occur during and after underwinding in particular during doffing of the cops and rupture of the yarn connected with this process. Method according to one of the preceding claims, characterised in that during the formation of the reverse winding and/or the underwinding the condition [T/m = αm .VNm = N/L] is being maintained, with T = number of turns per meter, m = unit of length, am = torsion coefficient, Nm = yarn count, N = turns of the spindle in revolutions per minute (r.p.m.), L = supply in meters per minute, whereat the course of the supply L above the time or the revolutions N are given and the revolutions N during the reverse or underwinding process respectively depend thereon or the supply L are being calculated depending thereon respectively. Method in particular according to one of the preceding claims for controlling a ring spinning frame with a drafting unit (12), a spindle (6) and a ring rail (20), whereat the drafting unit (12), the spindle (6) and the ring rail (20) are being kept in co-ordinated operation via respective drives (12a,22,16) by the control unit (24), and with a clamping device (28) for the yarn (10) in a position below a cop (8) on the spindle (6) characterised in that during the formation of the reverse winding at the end of the winding of a cop the control unit (24) is being operated in such a way, that in deviation of the theoretically calculated number of revolutions of the spindle N above the time, a reduced or increased number of revolutions N (t) are run, with the aim that after completion of the underwinding, the spindle comes to a standstill at the same time with or only slightly later than the drafting unit, that is one second later at maximum. Method according to one of the preceding claims, characterised in that when so called T-flange type spinning rings are applied, the spindles (6) are being controlled in such a way, that they come to a standstill in the position of the ring rail (20) that is at the height of the underwinding crown (26), and that only thereafter the ring rail (20) is being moved into the actual cop doffing position. Method according to one of the preceding claims, characterised in that during formation of the reverse winding or the underwinding, when producing knitting yarns the sliver receives a supplemental twist and that when producing crepe yarn the twist of the yarn is being reduced. 13. Method according to one of the preceding claims, characterised in that during the production of effect, flame or knop yarns at least from the point of time of formation of the reverse winding or underwinding, the number of revolutions of the drafting unit (12) or the supply L is kept constant, so that during this phase of the spin out process a smooth yarn without effects results. 14. Method according to one of the preceding claims, characterised in that the control unit (24) for example specifically for the drafting unit drive (12a) a frequency threshold is being determined below which frequency no flame, knop or other effects can be generated any longer. 15. Method according to one of the preceding claims, characterised in that in a program memory (24b) or via an input unit (24c) respectively, calculating parameters can be entered or retrieved by means of which in a data processor unit (24d) of the control unit (24) the speed variations are being subpressed at least during formation of the reverse winding or underwinding. 16. Method according to one of the preceding claims, characterised in that the ring rail (20) remains only during a maximum of two loops of the spindle (6), with the underwinding yarn length, in particular during ¾ of a loop, in the lowest position at the clamping device (18). 17. Method according to one of the preceding claims, characterised in that the lowering speed of the ring rail (20) after completion of the cop between the upper winding and the underwinding in relation to the number of revolutions of the spindle (6) and/or the supply speed in the drafting unit (12) is varied in such a way, that on the cop between 0.5 and 5 reverse windings are being positioned, that is loops of yarn (10). 18. ' Method according to one of the preceding claims, characterised in that the ring rail (20) is lifted from the lowest position to above the clamping device (28) before the drafting unit (12) and the spindle (6) come to a standstill. 19. Method according to one of the preceding claims, characterised in that the spindle (6) after stop of the drafting unit drive (12a) is still being rotated during a short period of time (T5-T4) or that it is stopped at the same time together with the drafting unit (12). 20. Method according to one of the preceding claims, characterised in that the position of the ring rail (20) is being measured during the course of movement by means of a distance transducer (16a), preferably being arranged on the ring rail drive (16), and that the control unit (24) is being programmed in such a way that after determination of the lowest position of the ring rail (20) within the section of the clamping device (28), the yarn supply preferably being measured within the drafting unit by the distance transducer (12b) on a roller of the drafting unit (12), and that a supply interruption occurs, if a desired yarn length is wound as underwinding at the clamping device (28) on the circumference of the spindle (6). 21. Spinning frame to carry out the method according to one of the preceding claims, with a drafting unit (12) and a drafting unit drive (12a), a spindle (6) and a spindle drive (22), with a ring rail (20) including the ring rail drive (16), whereat the drives are being linked with a control unit (24) and with a clamping device (28) for the yarn (10) below the cop (8), characterised in that a power section (24a) of the control unit is laid out in such a way, that at the end of the cop travel during the braking process of the drafting unit drive (12a) and of the spindle drive (22), the drafting unit drive (12a), by means of the control unit (24), can be controlled to obtain a modified amount of draft, in particular a higher draft. 22. Spinning frame to carry out the method according to one of the preceding claims, with a drafting unit (12) and a drafting unit drive (12a), a spindle (6) and a spindle drive (22), by which the number of revolutions in the drafting unit drive (12a) or the spindle drive (22) respectively are adjustable to one another in such a way, that a yarn with a changed twist in the sense of a higher strength of the finished yarn can be generated. 23. Spinning frame according to claim 21 and 22, characterised in that the control unit (24) comprises a power section (24a) a memory (24b), an input unit (24c) and a data processor (24d). 24. Spinning frame according to claims 21, 22 or 23, characterised in that above a clamping device (28) being shiftable along the spindle (6), an underwinding crown (26) or a cutting ring respectively, is fixedly fastened onto the spindle, whereat the arrangement is in such a way, that in the clamping position for the yarn, the clamping device (28) rests on the underwinding crown (26). 25. Spinning frame according to one of the preceding device claims, characterised in that the clamping device (28) on the side opposite of the ring rail (20), is spring loaded in longitudinal direction of the spindle (6). 26. Spinning frame according to one of the preceding device claims, characterised in that in the memory (24b) memory spaces are being provided for the twist (a), the cop mass (KM), the ring diameter (D) as well as the cop diameter (K), the sleeve length (HL) and the yarn count (Nm), and that in the control unit (24) furthermore a data processor (24d) is being provided by which the driving programmes for the drafting unit drive (12a), the spindle drive (22) and the ring rail drive (16) can be stored, or that programme modules are being provided for the mentioned drives. 27. Spinning frame according to one of the preceding claims for device, characterised in that the control unit (24) on the one hand is linked with the distance transducer (16a) or rotary transducer on the ring rail drive (16) and on the other hand with a distance transducer or rotary impulse generator (12b) on the drafting unit (12) or on the drafting unit drive (12a), and that within a data ' processor (24d) of the control unit, means are being provided, in order to make comparisons with the stored values of the memory (24b) in a comparator (24e), on the base of measured values in relation to the position of the ring rail (20) and the supply of the drafting unit (12), and in order to initiate switching conditions at an agreement of the values, in the power section (24a) of the control unit, by which the drafting unit drive (12a), the ring rail drive (16) and the spindle drive (22) can be switched. 28. Spinning frame according to one of the preceding device claims, characterised in that in a memory module (24b) motion laws for the process of acceleration and deceleration of the ring rail drive (16) are being stored, which in dependence on signals from the rotary inducer (16a) within the data processor (24d) can be retrieved. 29. A method for controlling a ring spinning frame with a drafting unit, substantially as hereinabove described and illustrated with reference to the accompanying drawings. Summary For controlling a spinning frame with a drafting unit 12, spindles 6 and a ring rail 20 and with a clamping device 28 for the yarn 10 in a position below a cop 8, starting from the point of the formation of a reverse winding, the twist and/or draft and the number of revolutions are being changed in such a way, in that adapted i.e. higher or lower strength proportions or characteristics respectively, of the yarn result within the section of the reverse winding or underwinding. Thus the operating reliability of the spinning frame is increased, in particular in that unwanted thread breaks are avoided or in that desired thread breaks are being obtained. (Fig. 2)

Documents:

782-mas-2000-abstract.pdf

782-mas-2000-claims filed.pdf

782-mas-2000-claims granted.pdf

782-mas-2000-correspondnece-others.pdf

782-mas-2000-correspondnece-po.pdf

782-mas-2000-description(complete) filed.pdf

782-mas-2000-description(complete) granted.pdf

782-mas-2000-drawings.pdf

782-mas-2000-form 1.pdf

782-mas-2000-form 26.pdf

782-mas-2000-form 3.pdf

782-mas-2000-form 5.pdf

782-mas-2000-other documents.pdf

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