EP1009870B2 - Regulated drawing frame - Google Patents

Description

The invention relates to a drafting system, wherein the drafting device is preceded by a carding machine with a fiber-band-forming device for producing a sliver, which is the drafting system, which is arranged downstream of a tape storage.

From the practice Regulierstreckwerke known at the end of the card from the following publications: JP-Gbm-56017/78 Nihon Keikizai KK, JP-A-155231/77 Nagoya Kinzoku Harinuno KK, DE-A-1931929 Zinser, DE-A-2230069 Texcontrol, CH-B-599 993 Graf, EP-C-354 653 Hollingsworth, EP-A-544425 Hollingsworth, EP-A-604137 Hollingsworth, EP-A-617149 Grossenheiner Textile Machinery GmbH, EP-A-643 160 Howa Machinery, Ltd., EP-A-692 560 Chemnitz Spinnereimaschinenbau GmbH, US-B-5400476 Myrick-White, Inc.

As nearest state of the art reference is made to the book by Wegener / Peuker "Abridged cotton mill", Mönchengladbach, 1965. There are presented on page 87, right column under the heading "2nd option: card sliver default units" various cards with drafting. All attempts to increase the degree of fiber orientation in the band significantly or to reduce the proportion of hook fibers significantly, however, are considered more or less failed. From page 87, left column of the cited book "Shortened cotton mill" shows that the transition from the cardan drum to the customer already reached in the card high fiber orientation level is deteriorated again. As a possible solution to this problem ("2nd possibility: card sliver default units") is discussed on page 88, left column, to use at the output of the card a drafting system, which has a delay of 1.5 to 2. However, as can be seen from page 88, left column, but also this delay height has not led to the desired result, the fiber orientation to increase such that can be dispensed in particular to subsequent route passages. It will rather, according to this text suggested "to make the fiber transition on the card so that the deterioration of the fiber orientation at the source is avoided, at least significantly limited."

It is an object of the invention to propose a drafting system according to the preamble of claim 1 which overcomes the problems described above in order to obtain an improved degree of fiber orientation or a substantial reduction of the proportion of hook fibers in a sliver presented directly from a card.

This object is achieved in that the draft of the drafting system is so high that thereby significantly increases the degree of fiber orientation in the band or the proportion of hook fibers is substantially reduced, wherein the sliver forming means for producing a sliver with a band thickness higher than 8 ktex, for example 10 to 12 ktex, and wherein the drafting system can produce a total draft of more than 2, preferably more than 3 and for example 3 to 6.

According to the invention, it is proposed that the drafting unit is followed by a belt deposit and the draft of the drafting unit is so high that it is ensured that the degree of fiber orientation in the formed sliver substantially increased or the proportion of hook fibers is substantially reduced. Information about stretching prior to depositing can be found in the book "Abridged cotton mill - Prof. Dr. Ing. Walther Wegener - Mönchengladbach 1965". This will be discussed in more detail below.

According to the invention, the delay is greater than 2, preferably between 3 and 6. This should additionally ensure that a sliver is formed with a high-quality fiber structure, which has a positive effect especially in subsequent processing stages.

In order to allow such a high distortion between the belt-forming device and the belt storage, the belt-forming device according to the invention produces a sliver having a relatively low fineness (high strength), for example at least 8 ktex and preferably 10 ktex or even more (for example 12 ktex). In order to make this possible, the card is preferably used with a relatively high working width, for example greater than 1200 mm. This can be done with a machine according to the EP Patent Application No. 866153 will be realized. The overall content of the mentioned EP application is hereby incorporated by reference as an integral part of the present description.

Alternatives that do not require wide cards are in EP-A-627 509 and US-C-5,535,488 been described.

The strip fineness after the drafting device can be, for example, 3 to 5 ktex. The delivery speed at the exit of the drafting system is for example more than 400 m / min. Preferably, such drafting is provided on the tape tray (see the textbook "Shortened cotton mill", page 72 and the mentioned therein CS patent 98,939 ), so that the sliver supplied by the drafting system as quickly as possible (without having to go through a long transport path) can be stored.

According to one embodiment of the invention, the drafting system is associated with at least one means which is suitable to detect a necessary control intervention in the drafting device drive to maintain a predetermined setpoint before or during the control intervention and to use to influence the basic speed of the drafting system.

As a result, any memory required between the textile-processing machine and the following regulating drafting system can be kept relatively small, since the regulating interventions are compensated by the tracking of the basic speed of the drafting system. You also get one Safety device that ensures that the drive speed (basic speed) does not drift with respect to a basic setting.

Preferably, the further means is suitable for detecting differences between the delivery speed of the source and the entry speed into the drafting system. The difference in speed is due to the change in the speed of the regulated drafting roller.

Likewise, the further means may be suitable for detecting long-term mass fluctuations with respect to a predetermined desired value.

Preferably, the further means is a sliver storage, which may be equipped with corresponding monitoring elements or sensors. Thus, the differences in the conveying speed of the sliver, which arise due to the variable and regulated withdrawal speed of the pair of input rollers of the drafting unit, can be recognized by the variable level of the memory and can be made an intervention in the basic speed of the drafting system. This pre-control is made, which ensures that the memory can be kept at a low level.

The sliver storage can be designed as a slack storage, the slack of the sliver loop can be continuous or discontinuous.

Furthermore, it is proposed that an additional sensor for detecting the fiber mass is provided, which can be arranged directly after the outlet of a drafting unit upstream textile material processing unit. This makes it possible to detect long-term mass deviations very early and to react with a corresponding intervention in the basic speed of the following drafting system.

The textile processing unit is a card, wherein the sensor attached to the outlet of the carding machine can be used at the same time for long-term regulation of the feed device of the card.

The further means may also consist of a sensor device for sensing the rotational speed of the regulated pair of rollers of the drafting system and at least one of the drafting upstream and constantly revolving conveyor roller pair for the fiber mass, via the determined speed ratio, the long-term mass deviation is determined and resulting therefrom intervention in the basic speed of the Drafting be made.

Fig. 1

eine schematische Seitenansicht eines Streckwerks mit vorgeschalteter Karde und nachgeordneter Bandablage,

Fig. 2

eine weitere Ausführung gemäß Fig. 1,

Fig. 3

eine weitere Ausführung gemäß Fig. 1,

Fig. 4

eine schematische Draufsicht auf ein Streckwerk mit zwei vorgeschalteten Karden, und

Fig. 5

eine schematische Darstellung in Diagrammform des Massenverlaufes des Kardenbandes in Verbindung mit der angeglichenen Drehzahlkurve des Streckwerks.

Further advantages of the invention are described in more detail with reference to subsequent embodiments and listed. Show it:

Fig. 1

a schematic side view of a drafting system with upstream card and subordinate tape storage,

Fig. 2

a further embodiment according to Fig. 1 .

Fig. 3

a further embodiment according to Fig. 1 .

Fig. 4

a schematic plan view of a drafting system with two upstream cards, and

Fig. 5

a schematic representation in diagram form of the mass profile of the card sliver in conjunction with the adjusted speed curve of the drafting system.

Fig. 1 schematically shows the representation of a carding machine 1, which is fed via a feed chute 3 and via a subsequent feed roller 2 with fiber material. The fiber material is taken up by the spool and processed in cooperation with Kardierelementen not shown. The carded Material is removed by a doffer roller 5 from the drum 4 and transferred to a schematically indicated extraction device 10. From this discharge device 10, the sliver 6 formed there passes in the conveying direction F to a slack store 14, which is equipped with pairs of input rollers 15 and 16 pairs of output rollers. The slack (sliver loop FS) is scanned by a beam sensor 20, which is provided with sensors arranged in series one above the other. This makes it possible to detect each position of the sliver loop FS exactly. The sensor signals are output via the line 21 to a control unit S.

From this control unit S, the drive motor M1 of the pickup roller 5 is controlled via the control line 7.

The output from the memory 14 sliver 6 is guided by a measuring member 70, which is designed in the form of a Tastwalzenpaares. The measurement result of the measuring member 70 is delivered via the line 71 to the control unit S. Subsequent to the measuring member 70, the sliver is guided into the drafting unit 30 with the roller pairs 24 and 25, in which it is warped.

The basic drive of the drafting unit 30 takes place from the motor M2, which is controlled by the control unit S via the line 40.

In practice, the motor M1 of the pickup roller 5 is in this case designed as a master motor (master), the motor M2 is tracked in its basic speed as a "slave" to comply with predetermined drive ratios. This base speed of the motor M2 can be overridden by the signals of the sensor 20, which will be discussed in more detail below.

The motor M2 drives a gear 32, from which a drive path 35 leads to the output rollers 25 and another drive path 36 to a control gear 33 (differential). From this control gear 33 is via the drive path 37, the input roller pair 24 of the drafting unit 30 driven.

The control interventions, which are necessary by evaluating the signals of the measuring member 70 based on a predetermined setpoint for balancing mass fluctuations (short and long wave), made by a control motor M3, which is controlled by the control unit S via the line 38 and regulating in the Regulator 33 engages. As a result, the delay between the roller pairs 24 and 25 is changed and compensated for mass fluctuations in the sliver.

The drive of the measuring roller pair 70 via the drive connection 68, which is removed from the drive path 37. As a result, the synchronization between the input roller pair 24 and the pair of measuring rollers 70 is determined.

The invention is now concerned with the improvement of the fiber orientation degree or the reduction of the number of fiber hooks (Faserhäkchen) in the card sliver. The term "card sliver" here means a sliver, which is delivered to one of the card subsequent band storage.

The importance of the degree of fiber orientation and the problems that arise from the formation of hooks in the card are in the textbook "Shortened cotton mill, sliver spinning process" (Editor: "Magazine for the entire textile industry", 1965) by Prof. Dr. med. W. Wegener and Dr. med. H. Peuker has been explained (page 82 ff, but see in particular pages 87 to 97). It is therefore clear that the use of a drafting system to improve the degree of fiber orientation in the card sliver is known (page 87/88: Chapter "Card sliver default aggregates", see also page 72 - "Graf Optima Card Slip Aggregating Unit"). Meanwhile, further proposals have been submitted for the use of a drafting system at the outlet of the card (see zBua US-C-4,100,649 ; US-C-3,703,023 ; Textile Asia, June 1989, page 20; CH-C-462 682 ; US-C-4,768,262 ; US C-5152033 ; US C-4947947 ; US C-5400476 ; US C-5274883 ; US C-5018248 ; DE-A2230069 ; EP-A-512 683 ).

A real Japanese release ( JP OS 51-2 from the year 1976; User Fuji Seiko KK) describes a drafting system on the carding machine with a yielding capacity of 1.1 to 2 times.

Since the publication of the mentioned textbook, the interest in direct spinning of card sliver (without intermediate passage passages) has even increased because such a method was favored by the success of rotor spinning (from 1970) - cf. DE-A-4047719 , A new proposal in this direction is in EP-A-544 426 where a delay between 6 and 8 is proposed, although significantly higher delays (12 or even 30) are mentioned. Nevertheless, it has not yet been possible to realize the direct spinning of card sliver (without a route passage) by means of the rotor spinning process.

In other words, it has hitherto been known to deposit card sliver (in a jug), to draw off and stretch the sliver at least once (from the jug) in order to increase the degree of orientation, after which the fibers can be spun (possibly after further processing steps). On the whole, no refinement of the original is desired in such stretching - e.g. combined six slivers into a nonwoven, which is then subjected to a sixfold delay.

The invention provides a drafting device for use between the belt-forming device and the tape storage of a carding machine, wherein the drafting system can generate such a high distortion that thereby significantly increases the degree of fiber orientation in the belt or the proportion of hook fibers is substantially reduced.

In particular, the stretching of the fiber sliver preceding the depositing (eg by means of the drafting device mentioned) can be used to significantly reduce the proportion of towing hooks (see the textbook "Shortened Spinning", page 90).

According to the invention, the sliver is subjected to a distortion of more than 2 and preferably more than 3. If possible, a delay of 5 to 6 should be used, but this can rarely be achieved between the card runout and the subsequent tape storage without disturbing the running behavior of the sliver.

In order to allow such a high distortion between the belt-forming device and the belt tray, the belt-forming device according to the invention produces a sliver having a relatively low fineness (high gauge) of at least 8 ktex and preferably 10 ktex or even more (eg 12 ktex). In order to make this possible, it is preferable to work with a relatively high working width of the card, for example greater than 1200 mm. This can be done with a machine according to the EP patent application No. 98 810 088.9 will be realized. The overall content of the mentioned EP application is hereby incorporated by reference as an integral part of the present description. The EP application was published on 23.09.1998 under the number 866 153.

Alternatives that do not require wide cards are in EP-A-627 509 and US-C-5,535,488 been described.

The belt fineness after the drafting system can be eg 3 to 5 ktex. The delivery speed at the exit of the drafting system is for example more than 400 m / min. Preferably, such drafting is provided on the tape tray (see the textbook "Abridged cotton mill, page 72 and the therein mentioned CS patent 98,939 ), so that the sliver supplied by the drafting system as quickly as possible (without having to go through a long transport path) can be stored.

In a method according to the invention, it is provided that a carded web is combined to form a sliver and that the band is drawn with a delay of at least 2, and preferably more than 3, prior to depositing.

In other words, a card is provided with a sliver-forming device, a sliver tray and a drafting device connected between the sliver-forming device and the sliver depositing device, wherein the drafting device is designed to generate a warpage greater than 2 and preferably higher than 3.

The drafting system can be formed as a homogenizing unit, ie it can be arranged to produce a controllable variable distortion, but this is not essential to the invention. Delay changes will lead to corresponding changes in the degree of orientation. The card itself can therefore be conveniently designed as a homogenization unit (eg EP-A-271 115 ), wherein the subsequent drafting system is designed to increase the degree of fiber orientation.

A controlled drafting system according to the invention has a total draft GV (between the infeed and outfeed roller pairs) of more than 2 and preferably 3 to 6. If the drafting system has a pre-drafting zone, which is not essential to the invention, the mean distortion in the controlled (variable) drafting zone can be adjusted, for example. 2.5, the warping in the other (fixed) drafting zone e.g. about 1.2. The "Vorverzug" (in the first

Default field) may e.g. 1.1 to 1.5 and the "main delay" (in the second, variable default field) amount to about 2.0 to 4.

The sliver thickness at the outlet of the drafting system is preferably 3 to 5 ktex, for example 3.5 ktex. The drafting arrangement is preferably arranged directly above the funnel wheel of a belt deposit, for example as shown in DE-Gbm-296 22 923. The sliver deposited in the pot can directly to the OE spinning machine, for example, after EP-A-627 509 to be delivered.

The invention is preferably (but not necessarily) used in combination with the other features of the invention described in the introduction.

The following is based on the FIGS. 1 to 5 described the influence on the basic speed of the drafting system, as claimed in claim 5.

In the execution according to the FIG. 1 The changes in the rotational speed of the pair of input rollers 24 counteract backwards against the conveying direction F and are absorbed in the memory 14 by changing the loop position FS. The scanning of the loop position can take place in steps, whereby at a certain amount of change via the control unit S, an override of the basic speed of the drive motor M2 takes place. This reduction or increase in the basic speed compensates for the effect of the speed change by the control intervention, in particular when regulating long-term mass fluctuations. The memory can therefore be kept to a minimum size.

As soon as the speed of the input rollers 24 increases, the slack of the loop FS decreases while the take-off roller 5 continues to be supplied. This is detected by the sensor 20 and the base speed of the motor M2 is correspondingly lowered. As a result, the speed of the input rollers drops at a constant changed default ratio in the drafting system 30 also, whereby a return of the sliver loop is made to its original position.

With the drive of the drafting unit 30 of the drive of the subsequent tape tray 60 is fixedly coupled via the drive path 42 which is removed from the transmission 32 and leads to a transmission 50.

From the gear 50, the calender rolls 47, the funnel wheel 48 and the can plate 49 are driven via the drive path 51 shown schematically.

Between the roller pair 25 and the calender roller pair 47, a monitoring member 44 is still arranged, which is connected via the line 45 to the control unit S. This serves for the final monitoring of the number of the sliver formed and switches off the machine if the number is outside a certain tolerance range for a predetermined period of time.

The sliver is deposited on the calender rolls 47 and the funnel wheel 48 in a can K in loop form, the can K is rotated during the depositing operation on the can plate 49.

In Fig. 2 a device is shown, wherein following the discharge device 10, a pair of measuring rollers 55 is arranged, which is connected via the line 56 to the control unit S. This measuring element 55 detects substantially the long-term mass fluctuations (drifting the number of the sliver). According to the signal of this measuring member 55 in comparison with a predetermined setpoint, a control signal is generated in the control device, which is used to override the basic speed of the motor M2. This can be reacted early on a subsequent control intervention in the drafting system 30 to keep the memory at a constant level of sliver loop.

The memory 14 is in this case only provided with two sensors S1 and S2, which only respond when the sliver loop FS moves outside a predetermined tolerance range. As a rule, there is a fault and the machine (system) is switched off. The signal of the measuring member 55 is used in addition to the regulation of the drive motor MS of the feed roller of the card 1 to the drift of the number already at the card. The motor MS is controlled by the control unit via line 53.

The remaining elements correspond to the embodiment of Fig. 1 , which is not discussed here.

Fig. 3 shows a further embodiment, wherein a pair of delivery rollers 11 is arranged downstream of the trigger device 10. The speed of this pair of rollers is monitored by a sensor 12. Likewise, in this case the feed roller pair 24 of the drafting system 30, a speed sensor 62 associated with which is connected via the line 63 to the control unit S.

The execution of the memory 14 corresponds to the embodiment, which already in the embodiment of FIG. 2 has been described.

If no control intervention is required (constant band number), the measured speed ratio between the mentioned roller pairs (11, 24) remains constant. As soon as a drift of the tape mass in one or the other direction is determined via the measuring member 70, a control intervention takes place, as a result of which the rotational speed of the input rollers 24 changes. This also changes the speed ratio between the roller pairs 11 and 24, which is generated according to the change, a control signal from the control unit S, the base speed of the drafting 30 and the motor M2 changes or overrides, as in the example of Fig. 2 described to compensate for the control intervention.

The remaining elements or controls correspond to the embodiment of Fig. 1 , which is why this will not be discussed in more detail.

Essentially, the compensation of the control intervention on the override of the basic speed of the drafting system 30 refers only to the long-term mass fluctuations and not to the short-term, since these fluctuations are not significant and usually compensate themselves over time.

In Fig. 4 an embodiment is shown, wherein two cards 1a, 1b work side by side in parallel. The cards are also provided with feed rollers 6a, 6b, briseur 3a, 3b, tambour 2a, 2b and take-off roller 4a, 4b. The drive of the pickup rollers 4a and 4b is schematically indicated by 75 and 46, which are connected via a control line L8 and L9 to the control unit S. The drive 20a or 20b of the feed rollers 6a and 6b is also connected via the control lines L7 'and L7 "to the control unit S. In order to enable the interaction of both cards 1a, 1b, the control unit S and the respective control lines L8 and L9 ensures that the rotational speeds of the pickup rollers 4a and 4b are coordinated, that is, the drive 46 of the pickup roller 4b is tracked as a "slave" the drive 75 of the pickup roller 4a, which acts as a "master".

The fiber slivers Fa and Fb emitted by the respective card 1a or 1b are guided by a respective sensor 10a or 10b in order to scan their mass. Subsequently, the slivers Fa and Fb each pass into a slack memory 11a and 11b. In these memories, sensors O1, U1 and O2, U2 are mounted for scanning the fill level or the slack of the sliver loops. The sensors O1, O2 scan an upper position and the sensors U1, U2 a lower position of the sliver loop. Between the respective upper sensor and the lower sensor is the tolerance limit within which the sliver loop can move freely, without triggering a control intervention. However, it would also be conceivable to provide a sensor with continuous scanning. The sensors O1, U1 and O2, U2 are connected via the lines L10 and L11 to the control unit S.

After emerging from the two band memories 11a, 11b, the two slivers Fa and Fb are combined to form a single sliver FZ. This sliver FZ is then passed over a sensor 17, the sampling makes mass fluctuations in the submitted sliver FZ.

The fiber sliver FZ scanned by the sensor 17 then passes into the regulating drafting system 83. The values determined by the sensor 17 are delivered to the control unit S via the line L3.

The drafting system 83 consists in the example shown of three successively connected pairs of rollers 84, 85 and 86, wherein the pair of input rollers 84 is driven to adjust out of mass fluctuations in the sliver in the variable speed. The delivery roller pair 86 is driven by a main motor 65 and a subsequent gear 26 at a constant speed. As indicated schematically by the drive train 27, the middle roller pair 85 is also driven at a constant speed and has a constant speed ratio to the subsequent delivery rollers 86. Due to the predetermined speed ratio, a constant distortion of the sliver between the roller pairs 85 and 86 is performed. The motor 85 is controlled by a frequency converter 84 and via the line L6 from the control unit S. About the drive connection 92, a differential gear 28 is driven, which drives the input roller pair 84 via the drive train 31. The drive of the differential 28 can be overridden by a control motor 29, which is controlled via a frequency converter, not shown, and the line L5 via the control unit S. This override is based on the output from the sensor 17 signals that are compared with a stored in the control unit S actual value.

Following the Regulierstreckwerk 83 a reel KA is arranged, in which the output from the drafting fiber sliver F1 via a Kalanderwalzenpaar 34 and a funnel T is placed in a pot K. The pot K stands on a driven can plate (not shown), which sets the pot K during the filling in rotation. The can plate, the calender rolls 34 and the funnel wheel T become driven by a gear 96 via the drive path 98. The transmission 96 is powered by the schematically shown fixed drive connection 95 of the transmission 26, which is driven by the main motor 65. It can be seen that the delivery roller pair 86 with the drive elements of the reel KA directly via the gear 26 is fixedly coupled together. That is, as soon as the gear 26 is driven by the motor 65 at a lower speed, on the one hand the base speed of the roller pairs 84, 85 and 86 and on the other hand simultaneously decreases the speed of the calender rolls 34 of the funnel wheel T and the can plate of the tape tray KA.

As indicated schematically, a mixed signal MS is generated from the signals of the sensors 10a and 10b in the control unit S, which is compared with a setpoint value. The control signal SS resulting from this comparison is used to influence the set base speed of the motor 65. The functioning of the facilities is explained in more detail below:

At the beginning of the processing operation (starting process), the basic speed of the drafting system is tuned or tracked to the speed of the take-off roll 4a. Only when the operating speed is reached is the override of the basic speed enabled. The fiber slivers Fa and Fb emitted by the cards 1a and 1b are detected by the sensors 10a and 10b and the corresponding actual values (mass) are output to the control unit, where a mixed signal MS is generated. This mixed signal is compared with a desired signal "desired" and used to generate a control signal if the actual value deviates from the nominal value. This control signal goes to a frequency converter 94, which changes the speed of the motor 65 via the line L6 and thus the basic speed of the drafting unit and also the tape tray KA. It should be noted that the measured at the sensors 10a and 10b long-wave mass deviations simultaneously to control the drives 20a and 20b of the feed rollers 6a and 6b of the cards 1a, 1b are used. The drives are connected via the control lines L7 'and L7 "to the control unit S.

After leaving the sensors 10a and 10b, the slivers Fa and Fb are transferred to the slack stores 11a and 11b, in which they are scanned by the sensors O1, O2 and U1, U2. If the respective sliver loop is within the range between the upper and lower sensor, no additional control pulse is executed. However, for example, as soon as the sensor U2 indicates that the sliver loop of the sliver Fb is becoming too large, the direct tracking of the drive 46 of the doffer roll 4b from the drive 75, which is considered "master", is overridden and the speed of the roll 4b is reduced , As soon as the sliver loop moves back into the tolerance range between O2 and U2 after this intervention, the control coupling between the drives 65 and 46 is activated again. If the sliver loop does not return to the tolerance range after a predetermined time, there is a malfunction, which shuts down the entire system.

The situation is similar with the monitoring in the memory 11a, wherein when the fiber sliver loop of the sliver Fa outside the tolerance range between the sensors U1 and O1 and over a predetermined time also the system is switched off, since a fault can be assumed.

The fiber slivers leaving the respective store are brought together prior to entry into a subsequent measuring element 17 to form a common sliver FZ.

In the measuring element, the mass fluctuations are measured and delivered via the line L3 to the control unit S. By a set-actual value comparison in the control unit, a corresponding signal via the line L5 is delivered to the control motor 29, via the control gear 28, the speed of the input rollers 84 for balancing the mass variation changes. As a result, the delay between the roller pairs 84 and 85 changes. The delay between the roller pairs 85 and 86 remains constant.

The thus warped sliver F1 is discharged from the drafting unit and stored on the calender rolls 34 and the funnel T in a can K looped.

It is advantageous for the structure of the fiber amount if the total draft of the drafting system 83 is selected to be greater than 3, since this can partially resolve the drag hooks created during the removal process of the fiber material on the card during the drafting process, which has an advantageous effect on subsequent processing processes.

By pre-control of the basic speed of the drafting unit, it is possible to prematurely compensate for effects of a subsequent control intervention in the drafting system, so that the control intervention, especially for long-term mass deviations must not be caught only by the respective sliver storage. Thus, an oversizing of the sliver storage is unnecessary. This compensation is described below using the diagrams of Fig. 5 explained in more detail:

Starting from a base or operating speed U1, a drift of the mass m outside of a predetermined tolerance range To is detected at the time T1 via the sensors 10a, 10b. If now the drifting of the mass takes place at the time T1 without intervention in the base speed, the process would be as follows: Due to the lower mass submitted to the drafting system 83, the delay between the pairs of rollers 84 and 85 must be reduced. That is, via the control motor 29 and the differential 28, the speed of the input roller pair 84 is increased, whereby at the same time the delay between the roller pairs 84 and 85 is reduced, since the speed of the roller pair 85 remains constant. By reducing the speed of the input roller pair 84 and the feed rate of the delivered sliver F reduced. Since the carding machine or the doffer roller is operated at constant speed, the original delivery speed of the sliver from the card remains the same. The resulting difference between the delivery speed of the card and the changed intake speed of the sliver at the drafting system 83 is collected by the sliver storage 11 a and 11b. That is, the excess supplied amount of sliver F fills the sliver storage 11a, 11b until again equal ratios between the discharge speed of the card and the drawing speed of the drafting are available. This compensation can then be brought about again as soon as the control engagement with the feed roller 6a, 6b produces its effect on the delivery to the card. If these mass deviations occur alternately once upwards or downwards, this has no major effect on the degree of filling of the reservoirs 11a, 11b. The tape storage 11a, 11b need only have a sufficiently large capacity. However, if these mass deviations occur at regular or irregular intervals substantially in one direction, the available capacity of the buffer in the band memories 11a, 11b will soon be at the limit.

In order to avoid these disadvantages and to keep the required capacity of the tape storage to a minimum, an intervention in the base speed of the drive motor 65 is now performed. As soon as, for example, at time T1, the mass deviation determined via the sensors 10a, 10b is outside a predetermined tolerance range To, the speed of the motor 65 is also changed with a time delay t. From the upper diagram it can be seen that the mass becomes smaller, whereby the draft in the drafting system 83 must be reduced by increasing the rotational speed of the pair of input rollers 84. Now in as in the bottom diagram in Fig. 5 shown, the base speed of the motor 65 is lowered to U2, so the triggered via the control motor 29 speed increase compared to the pair of rollers 85 is almost completely compensated. This is special from the representation of the lower two curves of the Fig. 5 can be seen, wherein the lower curve shows the speed change of the pair of input rollers 84 with respect to a constant speed of the roller pair 85. It can be seen that the detected at the time T1 from the sensors 10a, 10b mass reduction of the delivered sliver leads to an increase in the rotational speed U14 of the roller 84 relative to the roller pair 85 to compensate by reducing the delay this thin spot. If the sliver loop is still within a predetermined tolerance range, no additional control signal is generated for further influencing the basic speed. By simultaneously reducing the base speed U1 of the motor 65, this speed change of the roller 84 is approximately compensated, that is, the entire speed level of the drafting system 83 is shut down evenly by the driving relationship, so that despite changing the speed ratio between the roller pairs 84 and 85, the now existing The speed of the input roller pair is approximately at the same level that existed before the control intervention. This makes it possible that the retraction speed of the sliver FZ remains at a constant level even after a control intervention and the change of the speed ratio. This makes it possible that the sliver storage 11a, 11b only need to compensate for short-wave control interventions, the long-wave deviations are compensated by changing the base speed of the motor 65. The sensors U1, O1, U2, 02 serve as additional monitoring aid. For reasons of clarity was omitted in the curve of the roller 84 on the representation of the rashes, which are caused by the short-wave Ausregulierungen. These short-wave readjustments usually swing around the drawn curve up or down.

By lowering the base speed and the rotational speed of the drive elements of the tape storage is lowered synchronously, whereby the speed ratio between the supply roller 86 and the calender rollers 34 is maintained remains. This compensation of the long-wave drifts of the sliver mass can be performed relatively smoothly and slowly, so that the tracking of relatively sluggish elements of the tape tray KA no problems.

With the proposed device can be responded in good time to long-wave deviations in the sliver mass on the one hand with already known sensor devices and on the other hand, the need for the regulation at the entrance of the drafting system sliver storage are kept to a minimum.

Claims (5)

1. A drafting device, whereby a carding machine (1) with a fibre-forming device to create a fibre strip (6) is located upstream of the drafting device (30), a strip deposit element (KA) is arranged downstream of the drafting device (30), characterised in that the draft of the drafting device (30) is of such a degree that, as a result, the degree of fibre orientation in the strip is substantially increased, and the proportion of hook fibres is substantially reduced respectively, whereby the fibre-forming device is designed to create a fibre strip (6) with a strip thickness greater than 8 ktex, such as 10 to 12 ktex for example, and whereby the drafting device (30) can generate a total draft of more than 2, for preference more than 3, and, for example, 3 to 6.
2. The drafting device according to Claim 1, characterised in that the carding machine (1) features a working width greater than 1200 mm, for example 1300 to 1500 mm.
3. The drafting device according to one of Claims 1 or 2, characterised in that the drafting device (30) features a delivery speed of greater than 400 m/min.
4. The drafting device according to any one of the preceding Claims, characterised in that the drafting device (30) is provided on the strip deposit element (KA).
5. The drafting device according to any one of the preceding Claims, characterised by a drive unit (M2) and a regulating device (M3, 33) for regulating out any mass fluctuations of a fibre mass (6) guided to the drafting device from a supply source (1), whereby at least one means (14, 55, 12, 62) is allocated to the drafting device (30) for the purpose of influencing the basic revolution speed of the drafting device.

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