EP0558719B1 - Drive for combing machines - Google Patents

Abstract

A process is disclosed for supplying a lap (10) that can be unwound from a lap roll (3) to a combing unit (16) of a combing machine. The lap roll (3) lies on rotary winding cylinders (4) and at least one of the winding cylinders (4) is linked to a drive. In practical operation, it has been ascertained that as the diameter (D) of the lap roll decreases, the lap feeding speed is reduced. This deviation also affects the combed sliver formed in the combing machine and is generally known as drift. The grist of the combed sliver to be formed by the combing machine is thus no longer ensured. In order to compensate for this drift, it is proposed to increase the speed of rotation of the driven winding cylinders (4) during a lap roll (3) unwinding time interval.

Description

The invention relates to a method for supplying a cotton roll that can be rolled off a cotton roll to a combing unit of a combing machine according to the preamble of patent claim 1.

In such known combing machines, e.g. from CH-PS 625 564, the cotton to be combed is presented to the combing unit in the form of a cotton wrap. The cotton roll is supported on two winding rollers, at least one of which is driven, during the unrolling of the cotton wool. The cotton is removed from the roll in front of the front roll. The cotton unwound in this way reaches the clamping area of a pair of pliers via a feed cylinder and is combed out at its front end, which projects beyond the pliers, when the pliers are closed by means of a round comb arranged below the pliers. After the combing-out process, the pliers are opened again and the combed-out fiber beard is transferred to a subsequent pair of tear-off cylinders. In this tear-off process, a fixed comb stuck into the fiber beard to be torn off can have an additional combing effect. During the combing process, the pliers move back and forth. To make it easy to start a new roll, the driven winding roll is separated from the drive by a coupling, so that both winding rolls can be freely rotated.

A previously described embodiment of a combing machine is also known from the previously published EP-OS 360064, the front winding roller being driven by a separate drive motor which is controlled by a control device. This control device has the task of synchronizing the controls of the separate drive motor for the feed cylinder, the drive for the winding roller and the drive for the pliers, the round comb and the tear-off cylinder.

The cotton roll lies freely on the two winding rollers with its full weight (20-25 kg). This creates an indentation in the area of this support with respect to its outer diameter due to the elastic flexibility of the winding. After passing the support point, the winding expands again to its original diameter minus the thickness of a wad of cotton wool. As the winding diameter decreases and the weight decreases, this indentation depth decreases. The winding rollers are toothed in order to ensure better transport with a smaller winding diameter.

The peripheral speed of the winding is greater on its outside diameter than the peripheral speed in the area of the smallest distance between the central axis of the winding and the contact surface of the winding roller. From this it follows that the more the diameter and thus the weight of the winding decreases, the lower the indentation depth and thus also the penetration of the cotton into the toothing and the difference between the peripheral speed in the area of its outer diameter and the peripheral speed in the area of the smallest distance between the central axis of the winding and contact surface of the winding roller. On the basis of these different speed ratios, a different delivery speed of the cotton wool can arise depending on the diameter or weight of the cotton roll. In addition to the described influence of the changed indentation on the delivery speeds of the cotton wool, the changed dynamic interaction between the intermittent drive of the feed roller and the constant drive of the winding roller also has an influence on a changed delivery speed via the unwinding process of a cotton roll, even with decreasing winding weight. Due to the influences mentioned, the tensioning of the cotton between the winding roller and the feed cylinder changes during the unwinding process.

As studies have shown, the result of this is that, at the start of the unwinding process, the combing unit is presented with a thicker cotton wool for combing out than when the cotton wool roll runs out.

This deviation is generally referred to as drift and can amount to up to 5% depending on the structure of the cotton roll, material and other parameters.

A separate drive for the winding rollers, which is controlled by a control device, is also shown in an earlier application by the applicant with the number CH-140/90 from January 17, 1990. The control of the separate drive for the winding rollers is necessary for the application process of a new cotton wool in the combing tongs. A continuous adaptation of the winding roller drive during the unwinding process is not provided.

These differences in the mass presented for combing during the unwinding of a reel have a disadvantageous effect on the numbering of a sliver formed after the combing units.

The combing machines are usually provided with eight combing heads, each of which is presented with a wad of cotton wool for combing out. The combed cotton is then combined into a sliver. This creates eight fiber slivers, which are fed next to each other to a subsequent drafting system after corresponding deflection. The fiber slivers stretched in this drafting system are combined to form a single fiber sliver, which is then usually placed in a can.

For example, a belt monitoring device is located between the drafting system and the can rack, as can be seen from the Rieter E7 / 5 installed, which monitors the number of the sliver running out.

The resulting drift of up to 5% described above during the unwinding process of the reel can be measured with this tape monitoring with a time shift.

It is therefore the object of the invention to propose a method and a device for driving the combing machine or the winding rollers, which enables the formation of a uniform sliver in the combing machine and a uniform supply of a cotton wool mass to a combing unit independently of the Guaranteed size of the wadding.

The solution is that the speed of the driven winding rollers or even just one winding roller is changed within a rolling interval of a cotton roll.

The expression roll-off interval refers to the period between the fitting of a new and full roll and the running out of the cotton wool from a sleeve of the roll. The invention is not limited to the fact that both winding rollers are connected to the drive, but also to the drive of only one winding roller, the other winding roller being dragged along via the cotton winder via friction.

It is proposed that the speed of the driven winding roller be increased within the unwinding interval.

In a further embodiment of the invention, it is proposed that the winding rollers be driven by an independent drive, which can be controlled or regulated independently of the drive of the combing units.

The term combing units are essentially to be understood as the tongs with feed cylinder and fixed comb, the round comb and the tear-off cylinder.

The proposed independent controllability ensures an adaptation of the speed increase of the winding rollers during a rolling interval for different winding templates. This also makes it easy to make corrections to the speed changes.

The total length of the wound cotton is generally known from the process of winding formation upstream of the combing machine. Based on the required feeding speed of the cotton to the combing units, a conclusion can be drawn as to the time interval in which the cotton is unwound again from the sleeve.

It is therefore proposed to adjust the speed adjustment of the winding rollers via the control of the drive in accordance with the dimension of the unwound lap length. Various parameters can be used for the purpose of adaptation. These parameters can e.g. Experience or test values, which specify a corresponding adjustment of a speed increase. The speed can be increased continuously using a curve or discontinuously within certain time intervals. Another determination to determine the parameters that are used to regulate the drive of the winding rollers is the direct detection of the mass of the rolled cotton between the front winding roller and a feed cylinder of a pair of tongs via a capacitive measuring element. The measured values determined in this way produce a signal in comparison with a predetermined target value, which results in the readjustment of the drive of the winding roller.

As further proposed, there is also the possibility of the mass of the formed after the combing units To detect fiber sliver via a measuring device, the drive of the winding rollers being readjusted when a setpoint drifts. However, the combing out must also be taken into account. Controlling the drive of the winding roller by monitoring the winding weight is also conceivable.

It is also proposed to automatically return the drive of the winding rollers to its initial speed when changing the winding. This ensures that the same conditions are created for the processing of each roll. Via a sensor, e.g. described in CH-PS 572 529, the leakage of the cotton from the sleeve is monitored. This signal can be used to return the winding roller drive to its initial position.

When using an automatic winding applicator for a new winding, it is necessary to provide an override option for the speed and the direction of rotation of the winding rollers with respect to the initial speed.

The proposed method for adjusting the speed during the unwinding interval is advantageously to be used when a block change of the windings is carried out on the combing machine. This means that all windings on all eight combing heads are changed at the same time. This ensures that the reduction in diameter is the same on all combing heads when the reels run out.

However, it is also possible to carry out the method according to the invention in a combing machine with a so-called "wild change". The expression "wild change" means that the wadding is changed individually according to the expiry. In this case, it would be necessary to carry out each individual combing head in order to carry out the method according to the invention to assign a separate drive for the winding rollers in order to do justice to the different processes of the bobbins between the individual combing heads.

Further advantageous embodiments of the invention are described and shown in more detail with reference to the following exemplary embodiments.

Fig. 1

zeigt eine schematische Seitenansicht eines Kämmkopfes mit einer Steuereinrichtung für die Wickelwalzen.

Fig. 2

zeigt eine vergrösserte Teilansicht nach Fig. 1.

Fig. 3

zeigt eine verkleinerte Ansicht nach Fig. 1 mit einem schematisch dargestellten Streckwerk und einer Bandablage.

Fig. 4

zeigt ein Diagramm für eine mögliche Drehzahlanpassung pro Abrollintervall eines Wickels.

Fig. 5

zeigt eine schematische Teilansicht eines Kämnkopfes nach Fig. 1 mit einer möglichen Messeinrichtung für die Watte.

Show it:

Fig. 1

shows a schematic side view of a combing head with a control device for the winding rollers.

Fig. 2

shows an enlarged partial view of FIG. 1st

Fig. 3

shows a reduced view of FIG. 1 with a schematically illustrated drafting system and a tape storage.

Fig. 4

shows a diagram for a possible speed adjustment per rolling interval of a reel.

Fig. 5

shows a schematic partial view of a comb head of FIG. 1 with a possible measuring device for the cotton wool.

1 shows a combing head 1 in a schematic side view of a combing machine. Eight such combing heads 1 are usually installed on a combing machine. For reasons of clarity, the exemplary embodiment is shown and described on only one combing head, the drive units listed here being used together for all combing heads. This is particularly necessary for combing machines in which a previously described block change takes place. The drive shafts thus extend over the entire width of the combing heads, the drive from one side of the combing heads done centrally. However, it is entirely conceivable to assign separate drive units or controls to each combing head or groups of combing heads.

In its upper area, the combing head 1 shown is provided with a receptacle 2 for a cotton roll 3. The cotton roll 3, which is referred to in the further description only as "roll", lies freely on winding rolls 4 and 5, which are rotatably mounted in a frame 6. The front winding roller 4 is connected to a motor 8 via a drive train 7. The motor 8 could also be arranged in direct alignment with the winding roller. Furthermore, it would also be conceivable to arrange a transmission gear between the motor 8 and the winding roller 7. However, this is of secondary importance for the representation of the arrangement according to the invention and should only be mentioned here. The motor 8, for example an electric motor, is controlled via a control unit 9. When the roll 3 rolls out in the clockwise direction Z, the cotton web 10 unwound from the winding 3 reaches a deflection roller 11 on which a spring-loaded feeler roller 12 is seated. An incremental encoder 13 is attached to the side for speed detection of the roller 12. The signal of this speed sensor is transmitted via a path 14 to a controller 15, from which corresponding control pulses are emitted to the control unit 9 after these signals have been converted. The cotton wool web 10 goes down to a combing unit 16. This combing unit 16 is formed by pliers 17 in which a feed roller 18 is rotatably mounted. This feed roller 18 is generally rotated by a relative movement between the upper and lower pliers of the pliers 17 via a ratchet drive (not shown). The pliers 17 are pivotably mounted on a drive shaft 20 via an articulated arm 19 and on a circular comb axis 22 of a circular comb 23 via an articulated arm 21. The round comb is provided with a comb segment 24. Seen in the direction of conveyance F of the cotton wool 10, the tear-off cylinders 25 follow after the forceps unit 17 Tear-off cylinder 25 of the circular comb 23 and the drive shaft 20 for the pliers 17 is carried out by a central drive unit 26, which is controlled by a control unit 27.

A sensor 29, which is aligned with the sleeve, is attached for scanning the roll 3 or for monitoring the runout of the cotton 10 from the sleeve 28. The signals generated by the sensor 29 when the cotton wool runs out are transmitted to the control unit 9 and 27 via a path 30.

2 shows the cotton roll 3 and the winding rolls 4 and 5 receiving the cotton roll 3 in an enlarged view. In the area of the support 30 of the winding roller 4 and the support 31 of the winding roller 5 of the winding 3, the winding is pressed in with respect to its outer diameter D. This indentation with the indentation depth results from the resilient and flexible winding structure. The contact surface of the outer circumference 32 of the winding roller 4 is at a minimum distance R1 from the center of the winding 3. In relation to the diameter, 2xR1 = D1. After passing the support 30, the winding expands again to its original diameter minus a rolled winding track with the thickness S. As is indicated schematically, the driven winding roller 4 is provided with a toothing 47. The rear roller 5 could also have such teeth 47. In the case of the winding roller 5, the possibility of storing the roller in a bearing arm 49 is indicated by dash-dotted lines, which is supported on a balance 50 and thus enables monitoring of the winding weight lying thereon.

Friction over the outer circumference 32 of the driven winding roller 4 rotates the winding 3 in the unwinding direction Z and unwinds the wadding web behind the support 30 from the winding 3. Assuming that the transmission of the rotary movement from the winding roller 4 takes place in the area of the support 30 with the diameter D1, the diameter D1 in with respect to the diameter D, a lower peripheral speed and thus a different delivery speed for the wadding 10. On the other hand, the peripheral speed of the winding roller 4 is constant, but different in the teeth. This means that with a decreasing winding diameter D and thus a decreasing weight of the winding 3, this indentation depth X decreases and the dimension D approaches the diameter D1 and the cotton is pressed less strongly into the toothing 47 of the winding rollers. The speed differences with respect to the diameter D or D1 are thus also reduced. This means that the delivery speed of the wadding web 10 approaches the rotational speed applied by friction with diameter D1 as the winding diameter D decreases.

Decisive for the delivery speed of the wadding web 10 is the rolling diameter D and the depth of penetration of the wadding into the toothed winding roller 4. It follows that the greater the difference between D and D1 or the indentation depth X, the greater the difference between the actual delivery speed Cotton 10 and the rotational speed applied in the area of the diameter D1. It follows from this consideration that the delivery speed of the cotton 10 at the start of the rolling process, i.e. with a full wrap, is larger than when the unwinding process is finished.

However, studies have shown that not only is the impact of the cotton's depth of insertion as the winding weight decreases for the changed delivery speed, but also the changed dynamic interplay between the feed cylinder and winding roller drive plays a role. Which of these two criteria is decisive for the resulting drift depends on the respective material and drive conditions.

Tests have shown that these differences are reflected in a drift of up to 5%.

There are no disadvantages for the combing process itself, especially since there is a so-called tensioning delay between the winding roller 4 and the feed roller 18, which is greater than 1.0.

Due to the previously described drift, the numbering of the sliver formed in the combing machine after the combing units cannot be guaranteed. However, this is absolutely necessary in order to achieve a uniform thread in the subsequent spinning processes. However, this is to be ensured by the method proposed according to the invention, that is to say the drift which arises is compensated for by the proposed method. The exemplary embodiment according to FIG. 1 shows a possible embodiment for carrying out the method and is now described in more detail:

The winding roller 4 driven by the motor 8 sets the winding 3 in rotation by means of friction. The unwound lap 10 is deflected downward by a deflecting roller 11 and reaches the area of action of a feed roller 18. This feed roller 18 is driven intermittently by the movement of the top tongs via a ratchet drive (not shown) and conveys the lap 10 into the area of the nip the pliers 17. If the pliers 17 are in a rear position (not shown), they are closed and part of the cotton wool 10, a so-called fiber beard, protrudes from the closed pliers 17 and is placed over a comb segment 24 of the rotating circular comb 23 combed out. The pliers 17 then move forward again and open. The combed fiber beard is delivered to a tear-off cylinder pair 25, between which an already combed fiber fleece is clamped. For the sake of clarity, the depiction of an additional fixed comb, which is generally used and which sticks into the fiber beard to be dispensed from above, has been omitted.

The tear-off cylinder 25, the round comb 23 and the drive roller for the pliers 17 are driven by a central drive unit 26 which is controlled by a control 27. The controller 27 and the control unit 9 are connected to one another via a path 33 and can be coordinated with one another. This coordination relates to the normal interaction during the comb play, with the engine speed 8 being readjusted as a result of a drift correction independently of this interaction. To determine the unrolled length of the wadding web 10, a roller 12 which is spring-loaded via a spring 34 is attached to the deflection roller 11, the wadding web 10 moving between the two. When the wadding web 10 is delivered, the feeler roller is set in rotary movement, this rotary movement being recorded via a speed or incremental encoder. This rotary movement is converted into a corresponding signal by a controller 15 and output to the control unit.

In the given example, the motor speed 8 and thus the speed of the winding roller 4 are readjusted at intervals in relation to the unwinding length of the winding path 10 determined by the sensing roller. The size of the readjustment is carried out in the example shown, as from within the control unit The diagram shown can be seen in steps, based on increments stored in the control unit. These predetermined adjustments of the rotational speed on the basis of developed length units L of the cotton wool 10 result from tests carried out and empirical values which were determined.

However, it is also possible to get by without the feeler roller 12 and to adjust the speed of the motor 8 linearly and continuously from the start of the rolling process on the basis of empirical values (FIG. 4). It can be seen from this FIG. 4 that the speed N1 of the motor 8 increases linearly to a value N2 until the winding change t1 and then again to the basic speed N1 is returned. The same linear increase occurs during the next unwinding process until the next winding change at T2.

It is also conceivable, as indicated in FIG. 2, to tap the weight of the cotton roll 3 via a scale 50 which supports the rear winding roller 5 via a bearing arm 49. The drive of the winding roller 4 can be controlled in accordance with the decreasing weight of the winding.

5 shows a further possibility which serves to regulate the winding roller drive. Following the winding roller 4, the mass of the unrolled cotton wool 10 is measured via a capacitive measuring element and compared in a controller 37 with a predetermined actual value. In the event of a drift occurring during the unwinding process, the controller 37 emits a signal to the control unit 9 when the desired value deviates via the path 36, which regulates the motor 8. This creates a closed control loop and the motor 8 or the speed of the winding roller 4 is continuously adjusted to the deviation from a desired value.

FIG. 3 shows a similar control device corresponding to FIG. 5. However, an irregularity of a fiber sliver 38 is detected, which was formed by a drafting device 39 which is arranged downstream of the combing heads 16. For reasons of clarity, the arrangement of the drafting system and the subsequent devices were rotated by 90 ° around the axis A. The sliver 38 is monitored via the measuring element 40 for the number position or mass per unit length. The signal generated in this way is fed to a controller 41, in which a setpoint / actual value comparison is carried out. If the actual value deviates from the target value, a control signal is transmitted to the control unit 9 via a path 42 for the readjustment of the motor 8. It is also a closed control loop, but the Readjustment is delayed. With this type of control, however, the influence of the combing out must be taken into account in order to rule out incorrect measurements.

The sliver 38 guided by the measuring element passes via a deflection roller 43, via calender rollers 44 to a funnel wheel 45 which can be driven in rotation and finally deposits the sliver 38 in a can 46 for further conveyance to subsequent process stages.

In the embodiments of FIGS. 1, 3 and 5, a sensor 29 for monitoring the expiry time of the winding 3 is assigned to the winding. That is, as soon as the white cotton 10 is unwound from the black sleeve 28, the sensor 29 recognizes the black sleeve surface and emits a signal to the controller 9 for the motor 8 and to the controller 27 for the control unit 26. On the one hand, this causes the drive unit 26 to be stopped by the control unit 27 and also the drive 8 to be interrupted by the control unit 9. Simultaneously with this interruption, the speed mark for controlling the motor 8 is reset to the basic speed N1, which comes into effect at the start of the unwinding process of the new reel. As already described above, this basic speed N1 can be overridden when using an automatic reel changer until the start of the normal unwinding process.

Claims (11)

1. A method for supplying a lap (10) which can be unwound from a wound lap (3) to a feed roller (18) which is rotatably held in a nipper (17) of a combing unit (16) of a combing machine, with the feed roller (18) being driven intermittently with an evenly set average rotational speed (17) and with the wound lap (3) resting on rotatably held lap rollers (4, 5) and at least one of the lap rollers (4) is connected with a drive (8), characterized in that the rotational speed of the driven lap rollers (4) is changed within an unwinding interval of a wound lap (3).
2. A method as claimed in claim 1, characterized in that the rotational speed of the driven lap rollers (4) is increased within the unwinding interval.
3. A method as claimed in claim 1 or 2, characterized in that the lap rollers (4) are driven by a drive (8) which can be controlled or regulated independent from the drive (26) of the combing units (17, 23, 25).
4. A method as claimed in one of the claims 1 to 3, characterized in that the rotational speed of the lap rollers (4) is increased during the unwinding corresponding to the amount of the unwound lap length (L) from the lap (3) on the basis of predetermined parameters.
5. A method as claimed in claim 4, characterized in that the unwound lap length (L) between the lap rollers (4, 5) and the feed roller (18) of the combing unit (16) is determined by a measuring device (12).
6. A method as claimed in one of the claims 1 to 3, characterized in that the drive (8) of the lap rollers (4) is regulated according to the deviation of a measurement value of a measuring device (40) for determining the mass of a sliver (38) formed downstream of the combing units (16).
7. A method as claimed in one of the claims 1 to 3, characterized in that the drive (8) of the lap rollers (4) is regulated according to the deviation of a measurement value of a measuring device (35) between the lap rollers (4, 5) and a feed roller (18) which is arranged for the determination of the mass of the unwound lap (10).
8. A method as claimed in one of the claims 1 to 3, characterized in that the rotational speed of the lap rollers (4) is increased with the beginning of the unwinding process in predetermined time intervals during the unwinding.
9. A method as claimed in one of the claims 1 to 7, characterized in that the drive (8) of the lap rollers (4, 5) is automatically reset to the initial rotational speed (N1) at the beginning of the unwinding process by means of the control device (9) in case of a change of the wound laps (fig. 4).
10. A method as claimed in one of the claims 1 to 3, characterized in that the drive (8) of the lap rollers (4) is controlled on the basis of the decreasing lap weight.
11. A method as claimed in one of the claims 1 to 10, characterized in that the initial rotational speed and the direction of rotation of the lap rollers (4, 5) can be overridden for the purpose of an automatic lap piecing.

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