Method and device for warping with a cone sectional warper

Method for warping with a cone sectional warper that winds up the threads (10) in bands on a sectional warping drum (11), in which a support (12) for a thread guide comb is displaced parallel to the warping drum (11) by a forward feed drive, corresponding to the increasing thickness of the wind and predetermined warping data, with the first band being sensed during a measurement phase by a roll (15) under contact pressure and with the sensed displacement travel being recorded as a function of the number of rotations of the warping drum (11), and with the roll being drawn back and pressing on the wind lap after the measurement phase upon further winding in accordance with a mean value obtained during the measurement phase. In order to even out the formation of the wind, the pressure of the roll on the wind lap is continuously measured and monitored during the measurement phase and/or during subsequent winding or copying, and the displacement of the support is corrected in case monitoring results differ from a predetermined set value.

This invention relates to a method for warping with a cone sectional warper
 that winds up the threads in bands on a warping drum, in which a support
 for a thread guide comb is displaced parallel to the warping drum by a
 forward feed drive, corresponding to the increasing thickness of the wind
 and predetermined warping data, with the first band being sensed during a
 measurement phase by a roll under contact pressure and with the sensed
 displacement travel being recorded as a function of the number of
 rotations of the warping drum, and with the roll being drawn back and
 pressing on the wind lap after the measurement phase upon further winding
 in accordance with a mean value obtained during the measurement phase.
 In warping, a number of threads passing through the thread guide comb and
 guided by it are wound in bands on the warping drum that has a supporting
 cone. The first band of threads is wound up with a parallelogram cross
 section determined by the cone of the drum. The second band is then
 likewise wound up with a parallelogram cross section using the supporting
 action of the first band. Corresponding processes are repeated for the
 following bands of threads until the entire thread warp is wound up. The
 buildup of all of the bands of threads depends strongly on the properties
 of the threads to be wound up, for example on their capillarity, coloring,
 twist, spinning method, etc. Hard or soft wind laps are produced during
 the winding. For example, if the first band has too soft a wind structure,
 then the second band is worked into the flank of the first band, and
 consequently it does not grow high enough. Its warp length is shorter than
 that of the first band. If the wind lap structure of the first band is too
 hard, the second band becomes higher since the space for the second band
 has become smaller because of the swelling out of the first band. The warp
 length is then larger than that of the first band. Either of these leads
 to uneven distorted and patterned fabrics that accordingly are defective.
 DE 26 31 573 C3 discloses a method with the process steps mentioned
 initially, in which the measurement made under pressure is accomplished
 during the measurement phase. The first band is then to be copied under
 the same pressure and all of the other bands are to be copied under
 pressure.
 DE 34 32 276 A1 discloses a warping method in which a forward feed drive is
 controlled by a theoretically computed feed input to a processor. At the
 beginning of the first warp band, a measurement phase is completed, after
 which the wind lap formed is checked and compared with respect to its
 target state with the data stored in the processor. If necessary the warp
 slide length and the program stored in the processor are corrected, and if
 needed also with a second measurement phase. The first band is then warped
 completely and the forward feed motions during the warping of all of the
 following bands are then controlled as a function of those during the
 warping of the entire first band. Any required correction is made with the
 assistance of a sensor that is impacted by the roll and detects the roll
 position.
 In both of the methods described above, there is no monitoring during the
 copying of the first band of whether the lap buildup is correct. Instead,
 the measurement phase has to be set up and performed so that error-free
 warps can be wound.
 With this in mind, the underlying purpose of the invention is to improve a
 method with the features mentioned initially so that control of the lap
 buildup is still possible also during the copying of at least the first
 band.
 This problem is solved by continuously monitoring by measurement the
 pressure of the roll on the lap during the measurement phase and/or during
 the further winding and/or copying and by making a correction of the
 support forward feed in case the monitored result differs from a
 predetermined set value.
 Such a method makes it still possible to intervene in the buildup of the
 wind lap during the copying also. If the effective prevailing pressure
 does not correspond to the target pressure considering tolerance
 thresholds, then a reaction can be triggered that consists, for example,
 of a correction of the support forward feed. The support feed can
 therefore be reduced or interrupted or enlarged. This results in a reduced
 or increased growth of wind lap thickness, so that the wind lap buildup
 can still be smoothed out correctively even during the copying. Complete
 levelling of the pressure of the roll is possible during the entire warp
 buildup. As a consequence it is possible to exclude influences that cannot
 be detected during one measurement phase or even several measurement
 phases, for example the increase of thread tension from decreasing thread
 supply of the bobbins of the creel, or inaccurate input parameters whose
 deviations lead to a multiplication effect with lengthening warps.
 The method described with respect to the measurement phase can be carried
 out so that the measurement phase is started with a set pressure chosen as
 a function of characteristics of the threads to be wound up. The winding
 process is adapted to the properties of the threads to be wound up, which
 are determined, for example, by the number of capillaries, the coloration,
 by the twist, or by the spinning process. This adaptation is important
 because even small deviations of this item-specific pressure setting lead
 to errors when taking the average that is obtained based on the recorded
 values of measurements during the measurement phase. Such errors can also
 have considerable effects because the long warp lengths bring about a
 corresponding multiplication effect.
 However, the method described with regard to the measurement phase can also
 be implemented by determining a forward feed for the measurement phase
 whose magnitude is selected based on characteristics of the threads to be
 wound up. Such a determination of the forward feed that is thus calculated
 leads to a relative displacement of the warping drum with consideration
 not only of the cone angle but also additionally with consideration of the
 characteristics of the threads to be wound up. Such a method is
 particularly necessary when the pressure of the roll is to be practically
 zero during the measurement phase, or monitoring by measurement occurs
 only when copying. The use of a calculated forward feed during the
 measurement phase, however, can also be used as a supplement to monitoring
 the pressure of the roll on the wind lap during the measurement phase,
 with the calculated feed being modified in the measurement phase by means
 of the pressure sensor, so that after the measurement phase a correct
 forward feed again arises.
 It is advantageous for the entire warp wind to carry out the method so that
 the correction of the support feed also occurs during the copying from
 bands following the first band. This causes warped bands distant from the
 cone also to be symmetrical with the lap buildup of the first band.
 The method can be carried out so that the correction of the support forward
 feed occurs distributed stepwise over the turn of the drum in case of a
 pressure increase or decrease. This makes it possible to have
 corresponding control of the wind lap buildup, namely in the sense of
 smoothing over the circumference. For example, it is possible not to have
 to eliminate large pressure increases suddenly. Sudden pressure increases
 in the sense of pressure peaks occur, for example, in the area where the
 threads are hung on the cone drum. To some extent this is also the case
 when the hang points are embedded in the cone drum.
 It may also be beneficial to carry out the method in such a way that brief
 pressure changes occurring during the measurement phase and/or during the
 copying are not taken into consideration when taking the average and/or
 when monitoring the pressure. In case of such brief pressure changes it
 can be assumed that no serious changes of the wind lap buildup will occur.
 Therefore, if pressure changes that occur do not go beyond a given length
 of time, no correction is made of the support forward feed. Such a method
 is expedient when transverse ties have to be wound in, or when the band is
 compressed by hanging and then has to be smoothed out.
 The method can be implemented in such a way that the changes of forward
 feed and/or changes of support length occurring during the measurement
 phase, which have been detected as a function of the number of rotations
 of the warping drum, are copied in subsequent bands. As a consequence,
 changes of the wind lap buildup during the measurement phase of the first
 band are adopted in the beginning areas of the following bands
 corresponding to the measurement phase of the first band, so that there is
 uniformity of the wind lap buildup here in each case.
 It may be advantageous to implement the method in such a way that the first
 band is wound with constant thread tension, and during copying starting
 with the second band, there is control of the thread tension of the wound
 threads instead of or in supplement to a correction of the support forward
 feed. Changes of thread tension help to avoid forward feed corrections.
 They can replace them completely if pressure changes from the roll are
 unwanted.
 The invention also relates to a cone sectional warper with a support
 carrying a thread guide comb, that can be displaced parallel to a warping
 drum on a machine frame, with a motorized forward feed drive controllable
 through a controller to produce relative motions between the warping drum
 and the support corresponding to the growth of wind lap thickness, with a
 roll sensing the wind lap circumference with pressure, the displacement
 travel of which can be stored by the controller as a function of the
 number of rotations of the warping drum.
 To be able to carry out the method described above, the cone sectional
 warper is designed so that the roll is supported on at least one pressure
 sensor that feeds data to the controller during the measurement phase
 and/or during further winding and/or copying, which controls the roll in
 the sense of a correction in case the measured pressure differs from a
 predetermined setting. The roll impacted by the wind is able to feed data
 to a pressure sensor in a simple way, whose measurement can be interpreted
 by the controller. Such pressure sensors can detect both excessive
 pressure and insufficient pressure. To correct the pressure of the roll on
 the wind lap, the controller can be designed according to criteria
 generally familiar in control circles. It is not necessary to use special
 adjusting mechanisms in addition to the adjusting mechanisms that are
 necessary anyhow.
 When the roll is mounted on a pivot arm, the pressure sensor can be used
 largely independently of the elastic behavior of the roll, which is
 beneficial for the accuracy of measurement.
 The cone sectional warper can be designed so that the roll is pressed
 against the wind lap with a servomotor. Consequently, component parts that
 were needed to bring about the displacement of the roll as a function of
 the forward feed drive of the support can be omitted. For example,
 gearing, couplings, and spindle components are omitted. The servomotor
 installed in the support becomes active when the measured pressure of the
 regulating roll differs from the preset pressure. The servomotor displaces
 the support parallel to the axis, for example, when the pressure is too
 high. At the same time the support is displaced perpendicular to the
 warping drum axis by a translation corresponding to the slope of the cone.

A cone sectional warper has a warping drum 11 as an essential component,
 which can be rotated by a warping drum drive not shown. The warping drum
 11 at one of its ends has a cone 19 shown in FIGS. 1 and 3, which serves
 to support the threads 10 wound up in bands, that are fed to the cone
 sectional warper from the bobbins of a bobbin creel not shown. The threads
 10 form a band of threads that are arranged by a thread guide comb 13 in
 band width and are fed over a measuring roll 20. The measuring roll 20 is
 turned by the band of threads 10 so that it is possible to measure the
 thread length. From the measuring roll 20, the band of threads goes to the
 warping drum 11 while partially looped around a guide roll 21. The threads
 10 of the band of threads are knotted in bundles and fastened to hangers
 of the drum 11, not shown. The warping drum 11 driven in rotation then
 draws the threads 10 off of the bobbins of the bobbin creel and winds them
 up.
 The threads 10 are wound in bands according to FIG. 3. The threads of a
 band are wound on top of one another in many layers, with the bands being
 given a parallelogram cross section, for example the band 14. When this
 cross section is achieved, the first band 14 is supported by the cone 19
 of the warping drum in its axial direction. To achieve the parallelogram
 cross section of the first band 14 shown in FIG. 3, the windup points of
 the threads on the warping drum 11 and on the wound thread layers have to
 be displaced axially. This is accomplished by appropriate relative motions
 between the warping drum 11 and a support 12 that carries the warp comb 13
 and the measuring roll 20 and the guide roll 21. This relative motion
 parallel to the axis of the warping drum is the so-called support forward
 feed, which is produced, for example, by a forward feed drive, not shown,
 for example by a servomotor that is rigidly fixed to the support and
 meshes with a floor rail or with a toothed rail of the stationary machine
 frame 17, shown schematically in FIG. 1.
 The support is fed forward with consideration of the cone angle and in
 proportion to the growing lap thickness during the winding. While the cone
 angle is a fixed parameter and is appropriately considered in determining
 the support feed, the growing lap thickness has to be detected by
 measurement. This is done with a regulating roll 15 that is practically as
 wide as the band and is mounted to rotate on the support 12. The
 regulating roll 15 is adjusted to the warping drum 11 at the beginning of
 the wind, with the beginning of the cone 19' determining the initial
 position or zero position. Depending on the thread specifics, the wind lap
 16 builds up more or less quickly and the support feed accordingly has to
 be larger or smaller. If the yarn is thick, for example, the wind lap
 thickness increases more quickly and the forward feed and axial
 displacement of the regulating roll 15 have to be greater for each angular
 degree or for each rotation of the drum.
 The regulating roll 15 can be displaced perpendicular to the axis of the
 drum 11 in a way not shown, and will move against the warping drum prior
 to beginning the wind. When the warping drum 11 is rotated, the wind lap
 16 builds up in layers. At the beginning of the winding of the first band
 14, a measurement phase 23 is performed that extends, for example, through
 100 rotations of the warping drum 11. Therefore, the band is sensed under
 contact pressure during the measurement phase 23 and if the preset
 pressure is exceeded a motion parallel to the axis is initiated by the
 servomotor, and at the same time a radial motion, in small steps, until
 the preset pressure again prevails. After the measurement phase 23 is
 complete, an average is determined, ie. the average displacement travel
 for each rotation of the warping drum, and with it an average forward
 feed. The forward feed that is used during the copying subsequent to the
 measurement phase 23 corresponds to this.
 The measurement phase 23 extends only over a relatively small wind lap
 thickness. For this reason it is possible that the measurement is not
 accurate enough and that pressure changes of the regulating roll 15 on the
 wind lap 16 will occur during the further windup of the first band. The
 result would be an incorrect wind lap buildup. It is therefore provided
 for the pressure of the regulating roll 15 on the wind lap 16 to be
 checked.
 To measure the pressure of the regulating roll 15 on the wind lap 16 of the
 band 14, the roll is hinged to the support 12. The hinging is done with a
 pivot arm 39 at each end of the regulating roll 15 that permits motions
 relative to the support 12. Each pivot arm 39 carries one end 15' of a
 regulating roll shaft of the regulating roll 15 with a bearing 39'.
 Supported on the bearing 39' is a pressure pin 18' of a pressure sensor
 18, which in turn is fixed in position on the machine frame.
 Displacements of the regulating roll 15 and/or of the pivot arm 39
 therefore lead to a displacement of the pressure pin 18' and consequently
 to a measurement by the pressure sensor 18. The pressure of the regulating
 roll 15 on the wind lap 16 is therefore set by the regulating roll 15 with
 the support 12 being pushed against the warping drum 11 until the
 predetermined pressure is reached. Since measurement of the pressure
 sensor is available continuously, it is possible to monitor it
 continuously and change it if needed. This can occur during the warping of
 the first band, for example by the support forward feed being corrected
 during the copying process.
 The process during the measurement phase 23 is explained with reference to
 FIG. 4. FIG. 4 shows the pressure sensor 18 as a block that feeds its
 measurement to a regulator 27. The curve v1 of this pressure as a function
 of time is represented schematically in the regulator 27 by way of
 example. The pressure v1 fluctuates around an average v2 that is preset by
 a data store 27' of the regulator 27 as the thread-specific pressure. A
 tolerance zone for v2 is prescribed that is labeled in the regulator 27 by
 a minus sign and a plus sign. If the measured value v1 supplied by the
 pressure sensor 18 stays within these tolerance limits, no position change
 of the support is necessary. If the measurement by the pressure sensor 18
 exceeds the tolerance threshold of the regulator 27, a signal is sent to
 the controller 24. The servomotor 25 is actuated from there, and then
 displaces the support 12. The pressure sensor 18 exceeds the tolerance
 threshold of the regulator 27 almost constantly if no forward feed is
 prescribed and a forward feed is determined only in the measurement phase.
 The controller 24 feeds data to a memory 29 for the measurement phase with
 the forward feed per rotation of the warping drum 11. The data on winding
 speed, warp length, band width, number of bands to be wound, and thread
 tension are also stored in the controller 24.
 The process during the further winding of the first band after the
 measurement phase is described in FIG. 5. The regulator 27 continuously
 passes on the averaged forward feed from the measurement phase to the
 controller 24. The servomotor 25 is actuated from there, and in turn it
 displaces the support 12. The pressure sensor 18 continuously feeds
 measured values v1 to the regulator 27. When these values v1 exceed or
 fall below the thread-specific pressure transmitted from the data store
 27' in the .+-. tolerance threshold, the averaged forward feed from the
 measurement phase is modified until v1 again falls within the tolerance
 thresholds of v2. The support forward feed is corrected directly through
 the controller 24 to the servomotor 25. The controller 24 causes the new
 forward feed to be stored in a memory 30 for the copying phase of the
 first band. Such corrections are made repeatedly if needed. FIG. 3 shows
 copying phases 32 in each of which forward feed changes are made to hold
 the roll 15 in the tolerance zone of v2 if the forward feed determined in
 the measurement phase 23 is not suitable.
 FIG. 3 shows on the right flank of the first band 14 that this flank is not
 ideally smooth during the measurement phase 23. A stepwise gradation
 results on which the method has no effect, aside from the pressure of the
 regulating roll 15. The stepwise gradation arises because a pressure
 builds up immediately when winding is begun and the minus tolerance
 threshold of the regulator 27 is exceeded. In any event this is the case
 when no forward feed is prescribed. A copying phase 32 follows the
 measurement phase, during which the regulating roll 15 is withdrawn
 corresponding to v2 to corresponding to the average v2', not shown,
 obtained during the measurement phase 23, and then presses correspondingly
 on the wind lap 16. A finer gradation of the right flank of the first band
 is obtained, that has been illustrated by a straight flank section 33. If
 the necessity should arise in the course of further winding or copying to
 change the contact pressure, a correction of the support forward feed is
 made. Stepwise gradations again arise that are similar to those in the
 measurement phase and that have been illustrated enlarged as a detail A.
 The growth of the wind lap thickness of the entire first band 14 above the
 portion wound in the measurement phase 23 can be stored in the memory 30
 as a function of the number of rotations of the drum.
 After the copying of the first band 14, the copying of the second band 14'
 occurs, which is described in FIG. 6. The support forward feed is
 controlled by the memories 29, 30. The memory 29 controls the support
 forward feed in exactly the way it was recorded and stored for the
 measurement phase 23 of the first band. The memory 30 then takes over the
 control of the support forward feed through the controller 24 and the
 servomotor 25. Accordingly, changes of the support forward feed occur in
 the second band 14' in the same way as they were made in the further
 winding of the first band 14 after the measurement phase 23. The rest of
 the bands are warped correspondingly, both in accordance with the values
 of the pressure changes occurring in the measurement phase 23 and in
 accordance with the forward feed changes occurring during the copying
 phase of the first band in the modification phases 31.
 It is definitely possible for pressure peaks to occur, especially during
 the measurement phase 23, with which the tolerance zone of v1 is violated.
 Such pressure peaks occur, for example, from inlaid partial knots or from
 depressions in the drum circumference that are intended for hanging thread
 bundles. Since these pressure peaks, positive or negative, occur only
 briefly, they should not contribute to a correction of the support forward
 feed. Therefore, they can be ignored by the controller 24 and do not reach
 the memory 29, for example. Therefore they are not considered during the
 measurement phase when determining the average and are not considered
 during the copying phase when monitoring the pressure.
 Besides the first band 14, a second band 14' is also shown in FIG. 3. This
 second band 15 and any further bands are copied in accordance with the
 first band 14. Bands are therefore formed with wound sections 23' that are
 built up as in the measurement phase 23. Winding then continues like the
 rest of the first band after the measurement phase 23 until the complete
 second band 14' is finished. Pressure monitoring can also occur during the
 copying of the band 14' and of any other bands. Additional modification
 phases 31, not shown, are obtained in the second band 14' that can be
 adopted in the following bands.
 It is desirable for the forward feed to be corrected in steps. For example
 a pressure increase that occurs is corrected in the following rotation of
 the drum in tiny steps each 10 degrees of drum rotation. The number of
 steps depends on the pressure increase or on the pressure decrease. Small
 pressure changes cause fewer steps, while larger pressure changes require
 many steps. The number of steps can also go beyond one drum rotation.
 Stepwise forward feed correction results in an especially neat buildup of
 the band since large jumps in the forward feed are avoided.
 It has been assumed above that no forward feed is entered in the controller
 24, but that the pressure building up from the beginning of the wind leads
 to the minus tolerance being exceeded and causing a corresponding change
 of forward feed in which the cone angle is also taken into consideration.
 However, the method can also be carried out in such a way that the
 controller 24 has a fixed forward feed that is already effective during
 the measurement phase 23. The fixed forward feed, for example, rests on
 experience or is calculated by determining it as a function of
 thread-specific data such as thread color, twist, etc.
 A method is described with reference to FIG. 7 in which the copying of the
 second band 15 and of other bands is carried out in the way described in
 FIG. 6. At the same time, however, the regulator 27 is constantly fed
 pressure values from the pressure sensor 18. When the pressure sensor 18
 supplies values v1', v1" that are outside of the .+-. tolerance zone of
 the prescribed pressure v2 and/or the average value v2', a regulating
 circuit 40 is supplied with data and controls the thread tension. This is
 done with a regulating motor 41, not shown in detail, that affects an
 adjusting mechanism 42, not shown in detail, to control thread tension,
 for example on a central adjustment of the creel brakes that brakes the
 wound threads less strongly when the minus tolerance threshold v1" is
 exceeded, and that brakes the threads more strongly when the plus
 tolerance threshold v1' is exceeded. With this, the sensor 18 has a direct
 effect on the creel thread tension.