Title of Invention	REGULATED DRAFTING SYSTEM
Abstract	The present invention concerns a drafting system with a drive provided with a regulating device for levelling out mass variations in a fibre mass supplied to the drafting system by a supply source in which arrangement the mass variations are detected by at least one measuring sensor co-ordinated to the drafting system and the corresponding signals are transmitted to a control unit. For eliminating problems arising in the layout of the storage units and for security reasons it is proposed that a further means is co-ordinated to the drafting system which is suitable for detecting differences between the delivery speed of the supply source and the intake speed of the drafting system and apply it for influencing the base rotational speed of the drafting system or to detect long term mass variations from a pre-determined desired value in which arrangement these mass deviations detected are applied for influencing the base rotational speed of the drafting system.

Title of Invention

REGULATED DRAFTING SYSTEM

Abstract

The present invention concerns a drafting system with a drive provided with a regulating device for levelling out mass variations in a fibre mass supplied to the drafting system by a supply source in which arrangement the mass variations are detected by at least one measuring sensor co-ordinated to the drafting system and the corresponding signals are transmitted to a control unit. For eliminating problems arising in the layout of the storage units and for security reasons it is proposed that a further means is co-ordinated to the drafting system which is suitable for detecting differences between the delivery speed of the supply source and the intake speed of the drafting system and apply it for influencing the base rotational speed of the drafting system or to detect long term mass variations from a pre-determined desired value in which arrangement these mass deviations detected are applied for influencing the base rotational speed of the drafting system.

Full Text	The present invention concerns a drafting system with a drive arrangement with a regulating device for regulating mass variations in a fibre mass supplied from a supply source to a drafting system in which arrangement the mass variations are detected by at least one measuring device co-ordinated to the drafting system and transmitted to a control unit. The card operates at a constant (pre-settable) production rate, i.e. the fibre sliver is delivered at a pre-determined speed from the delivery arrangement. The function of a regulating drafting system imiplies that the draft be variable (controllable). Provision of a large sliver storage device between the card delivery and the drafting system intake is undesireable. Thus the delivery speed of the drafting system must be variable. This, however, creates problems concerning the drive for the sliver deposition or coiler system, the inertia of which is relatively considerable, arranged downstream from the the drafting system. Various devices are known, e.g. from the DE-OS-19 19 929, in which arrangement between the card and a regulating the drafting system arranged subsequently a sliver storage device is arranged. This can be seen in particular in the Figures 3 and 4 of the DE-OS. Adjoining the regulating drafting system a sliver storage device is arranged driven by a separate motor. The measured values determined by the pair of measuring rolls upstream from the regulating drafting system are compared to the pre-set desired values. The resulting deviation signal serves for controlling the drive motor for the intake pair of rolls of the drafting system in order to adapt the draft ratio, and to level out thin and thick places respectively. At the same time this signal is transmitted to the control device for the drive of the fibre sliver source, or of the card respectively, in such a manner that this drive also can be adapted correspondingly. The reaction of the card however, is subject to substantially higher inertia than the drafting system. The resulting differences in the maerial delivery, and in the material intake respectively, are levelled out in the sliver storage device adjoining the card. The storage device in this arrangement is provided with sensors for scanning the contents of the storage device. Based on the contents determined by the sensors in the sliver storage device the drives of the fibre sliver source (card) and of the fibre sliver take-up device (coiler) are changed accordingly in such a manner that the contents of the fibre sliver storage device is maintained substantially constant. This adaptation of the two drives however, results in additional differences, especially as the elements of the card (e.g. the card main drum) are subject to different inertia influences other than the elements of the sliver depositing device (coiler). Furthermore from the previously published DE-A1-44 24 490 a co-ordination of cards is known in which a storage device is co-ordinated to each card downstream and in which the card slivers delivered by the individual storage devices after passing through a drafting system are delivered to a common sliver deposition device or coiler. In order to compensate for the loss of one of he card slivers supplied to the drafting system the delivery speed of the drafting system is reduced until the missing card sliver has been re-inserted. In this arrangement a scanning sensor is co-ordinated to each individual card sliver. Owing to the reduction in delivery speed, corresponding to the loss of one card sliver, the fibre sliver reserve for the draw frame is exhausted more slowly than in the normal operating mode at higher intake speeds. In the example shown an increase of the card delivery speed also is proposed if the fibre sliver storage device arranged downstream is depleted in excess of a pre-determined value in such a manner that the operation of the subsequent draw frame is not jeopardized. The arrangement shown is suitable for levelling out massive short term variation (loss of a sliver). Levelling out long term deviations however, is not envisaged using this arrangement, or is solved unsatisfactorily only. For levelling out long period mass deviations in the fibre sliver delivered by the card it is proposed in DE-A1 29 12 576 that the thickness of the fibre sliver delivered by the card be measured and compared to a pre-set desired value. The signal thus determined is used in controlling the material supply device (feed roll) arranged upstream from the card. Owing to this arrangementlong period deviations in the mass of the card sliver delivered can be reacted on. Avoiding and eliminating of short wave deviations e.g. using a regulated drafting system is not envisaged in the arrangement described. The action in the control of the drive of the feed roll for compensating for long period mass deviations becomes effective, however, only after a major time delay. The solutions proposed thus far generally provide the drafting system for levelling out short term variations in the fibre sliver. They correspondingly propose application of a measuring sensor at the intake of the drafting system. Similar problems are encountered on other machines also, e.g. on the combing machine, if directly downstream from a textile processing unit a regulated drafting system is arranged which is driven at a regulated variable intake speed. It thus is the goal of the present invention to propose an apparatus which eliminates the problems described above in order to create a straightforward and functioning com- bination of a textile processing unit operating at essentially constant speed (supply source) with a subsequently arranged regulated drafting system unit. This goal is achieved in that at least one further means is co-ordinated to the drafting system which is suitable to detect a regulating action on the drive of the drafting system required for maintaining a pre-determined desired rotational speed before or during the regulating action and to apply it for influencing the base rotational speed of the drafting system. Owing to this arrangement the capacity of a storage device possibly required between the textile processing machine and the regulated drafting system arranged subsequently can be kept relatively small as the regulating actions are compensated for by adapting the base rotational speed of the drafting system. Furthermore a security device is created which ensures that the drive rotational speed (base rotational speed) does not drift from a base setting. The further means preferentially is suitable to detect differences between the delivery speed of the supply source and the intake speed of the drafting system. The difference in speed results from the change in the rotational speed of the regulated roll of the drafting system. The further means also can be suited for detecting long term mass variations relative to a pre-set desired value. Preferentially the further means is a fibre sliver storage device which can be equipped with corresponding sensor elements. Using said sensors the differences in the transporting speed of the fibre sliver can be detected which are caused by the variable and regulated take-off speed of the intake pair of rolls of the drafting system unit on the basis of the variable filling degree in the storage device and an the base rotational speed of the drafting system can be acted upon. Thus a pre-control is effected which ensures that the degree of filling of the storage device can be kept to a low level. The fibre sliver storage device can be laid out as a sliver sag storage device in which arrangement the sagging of the fibre sliver loop can be continuous or discontinuous. Furthermore provision of an additional sensor is proposed for detecting the fibre mass which can be arranged directly adjoining the delivery of a textile material processing unit arranged upstream from the drafting system. Using this arrangement long term mass deviations can be detected at a very early stage and thus corresponding action upon the base rotational speed of the drafting system arranged downstream can be effected. The textile processing unit in this arrangement can be a card in which arrangement the sensor provided at the delivery device of the card at the same time can be applied in a long term regulation of the feed device of the card. The further means also can consist of a sensor device for scanning the rotational speed of the regulated pair of rolls of the drafting system and of at least one pair of transporting rolls for the fibre mass rotating at constant speed in which arrangement the ratio of rotational speeds serves for determining the long term mass deviation, based on which value corresponding action upon the base rotational speed of the drafting system can be effected. As a further possibility it is proposed that the supply source consists of at least two coordinated cards arranged parrallel in which arrangement the drive of the second card via the control device is adapted to the drive of the first card, and that the fibre material delivered by the respective cards is detected by a sensor each and that the averaged signal generated by the two sensors is applied for acting upon the base rotational speed of the drafting system. In this manner on one hand synchronisation of the two cards and on the other hand the combined supply of the fibre slivers generated to a common drafting system are ensured in which arrangement fibre sliver storage devices, as proposed further, can be laid out in a small and compact arrangement. Advantageously the fibre sliver storage devices can be equipped with a scanning device. The scanning device for the fibre sliver storage device of the second card, the drive of which is co-ordinated to the one of the first card, or the slave card, can be applied for overriding the control link of the two card drives. This makes it feasible to compensate for short term deviations in the production of the second card. Expressed in other words the drive of the take-off roll of the second card is regulated until the fibre sliver loop in the fibre sliver storage device is brought back to within the sagging tolerance limits. This overriding action can be limited in time, i.e. in case of a longer duration of a deviation detected it is assumed a defect has occurred and the machines are brought to a standstill for inspection. As scanning sensors sag sensors can be applied which scan the saging of the fibre slivers in the fibre sliver storage device continually or discontinuously. It is proposed furthermore that downstream from the drafting system unit a sliver depositing device or coiler is arranged and that the draft applied in the drafting unit is so high that considerable increase of the degree of fibre orientation in the fibre sliver generated is achieved, and that the proportion of hooked fibres is substantially decreased. Notes pertaining to the drafting process before deposition of slivers can be found in the volume "Verkurzte Baumwollspinnerei (Abreviated Cotton Spinning)" by Prof. Dr. Ing. Walther Wegener - Monchengladbach 1965. These notes are referred to in more detail in the following. It is assumed that the draft ratio chosen is higher than 2, and preferrably ranges between 3 and 6. This should additionally ensure that a fibre sliver of high quality structure is formed which beneficially influences in particular the subsequent processing steps. In order to render feasible such a high draft ratio between the fibre sliver forming device and the sliver deposition or coiler device the fibre sliver forming device preferentially should generate a fibre sliver of low finness (or high linear density respectively), e.g. of at least 8 ktex and preferably 10 ktex or even more (e.g. 12 ktex). In order to render this feasible a relatively large working width of the card preferentially is chosen, e.g. exceeding 1200 mm. This can be realised using a machine according to our EP patent application No. 866 153. The whole contents of said EP application thus is considered as an integral part of the present description. Alternative solutions not requiring wide cards have been described in EP-A-627 509 and US-C-5'535'488. The linear density of the sliver after the drafting system can be e.g. 3 to 5 ktex. The delivery speed at the delivery of the drafting system can e.g. exceed 400 m/min. Preferentially a drafting system of such type is provided arranged on the sliver depositing or coiler device (compare the volume "Verkurzte Baumwollspinnerei (Abreviated Cotton Spinning)" p. 72 and the CS-Patent 98 939 mentioned therein) in such a manner that the fibre sliver delivered by the drafting system is deposited as soon as possible (without being transported oyer a long path). Furher advantages of the present invention are described in more detail in the following with reference to illustrated design examples. It is shown in the: Fig.1 a schematic side view of an inventive arrangement, Fig.2 a further embodiment according to the Fig. 1, Fig.3 an additional further embodiment according to the Fig. 1, Fig.4 a schematic top view of an arrangement with two cards according to the present invention, and in the Fig.5 a schematic diagrammatic view of the mass of a card sliver produced plotted in combination of the diagram of the adapted rotational speed of the drafting system. In the Fig. 1 a card 1 is shown schematically which is supplied with fibre material via a feed chute 3 and via a feed roll 2 arranged adjacent to it. The fibre material is taken over by the main drum 4 and is processed in co-operation with carding elements not shown. The carded material is taken off the main drum 4 by a take-off roll 5 and is transferred to a take-off device 10 indicated schematically. From this take-off device 10 the fibre sliver 6 formed there is transferred in the transporting direction F to a sag storage device 14 equipped with a pair of take-in rolls15 and with a pair of delivery rolls 16. The degree of sliver sagging (fibre sliver loop FS) is scanned by a column-type sensor 20 provided with a series of sensors arranged along a column. Using this arrangement any position of the fibre sliver loop can be detected precisely. The sensor signals are transmitted via the circuit 21 to a control unit S. From this control unit S the drive motor M1 of the take-off roll 5 is controlled via the control circuit 7. The fibre sliver 6 delivered by the storage device 14 passes through a measuring device 70 which is laid out in the form of a pair of feeler rolls. The value measured by the measuring device 70 is transmitted via the circuit 71 to the control unit S. Upon passing through the measuring device 70 the fibre sliver is transferred to the drafting unit 30 formed by the pairs of rolls 24 and 25 between which it is drafted. The base drive of the drafting unit 30 is effected by the Motor M2 which is controlled via the circuit 40 by the control unit S. In practical application the motor M1of the take-off roll 5 in this arrangement is laid out as the leading or master motor to which the motor M2 is co-ordinated in its base rotati- onal speed as a slave motor in such a manner that pre-determined drive conditions are maintained. This base rotational speed of the motor M2 can be overridden by the signals of the sensor 20 which is to be explained in more detail in the following. The motor M2 drives a gear arrangement 32 from which a branch drive 35 extends to the delivery rolls 25 and a further branch drive 36 extends to a regulating gear arrangement (differential gear). From this regulating gear arrangement 33 the intake pair of rolls 24 is driven via the drive train 37. The regulating actions required for levelling out mass variations (short and long term) according to the evaluation of the signals transmitted by the measuring device 70 in comparison with a pre-set desired value are effected by a regulating motor M3 which via a circuit 38 is controlled by the control unit S and which acts upon the regulating gear arrangement 33. Owing to this action the draft between the pairs of rolls 24 and 25 is changed and mass variations in the fibre sliver thus are levelled out. The drive of the pair of measuring rolls 70 is effected via the drive train 68 which branches off from the drive path 37. In this manner the synchronous movement of the intake pair of rolls and the pair of measuring rolls 70. Changes in the rotational speed of the intake pair of rolls 24 are acting backward, against the transporting direction F, and are taken up in the storage device 14 where the loop position FS is changed. Scanning the position of the sagging loop in this arrangement can be effected in steps in such a manner that if a certain amount of change is detected, overriding of the base rotational speed of the drive motor 2 sets in induced by the control unit S. Owing to this reduction, or increase respectively, in the base rotational speed the effect of the change in rotational speed caused by the regulating action, particularly in levelling out long term mass variations, are compensated for. The size of the storage device thus can be kept to a minimum. As soon as the rotational speed of the intake pair of rolls 24 increases, the sag of the sliver loop SF is reduced, the delivery speed of the take-off roll 5 remaining constant. This is scanned by the sensor 20 and correspondingly the base rotational speed of the motor M2 is lowered. Thus the rotational speed of the intake pair of rolls also is lowered, the adapted draft ratio in the drafting system 30 remaining constant, in such a manner that the fibre sliver loop is brought back to its original position. The drive of the sliver deposition device or coiler 60 arranged subsequently is permanently coupled to the drive of the drafting system unit 30, namely via the drive train 42 which branches off from the gear arrangement 32 and is connected to a gear arrangement 50. The calender rolls 47, the coiler gear 48 and the can turntable 49 are driven by the gear arrangement via the gear train 51 which is shown schematically. Between the pair of rolls 25 and the pair of calender rolls 47 a further scanning sensor 44 is arranged which via the circuit 45 is connected with the control unit S. This arrangement serves for the final control of the linear density of the fibre sliver the machine being stopped if the linear density exceeds a pre-determined tolerance field over a pre-determined period of time. The fibre sliver passes via the calender rolls 47 and via the coiler gear 48 is deposited in coils into a sliver can K which is rotated by the can turntable while the sliver is being deposited. In the Fig. 2 an arrangement is shown in which adjoining the take-off device 10 a pair of measuring rolls 55 is arranged which via the circuit 56 is connected with the control unit S. This measuring device 55 scans essentially the long term mass variations (Drifting of the fibre sliver linear density). The signal given off by this measuring device 55 is compared to a pre-set desired value in the control unit S and a corresponding controlling signal is generated which is used for overriding the base rotational speed of the motor M2. Owing to this arrangement a subsequent regulating action in the drafting system 30 can be reacted on early for maintaining a constant level of the position of the fibre sliver loop in the storage device. The storage device 14 in this arrangement is provided with two sensors S1 and S2 merely which are triggered only if the position of the fibre sliver loop FS exceeds predetermined tolerance limits. Such occurences are caused a rule by a disturbance, and the machine (plant) is switched off. The signal given off by the measuring device 55 additionally is used for regulating the drive motor MS of the feed roll of the card 1 for levelling out a drift in linear density aliready at the card. The motor MS is influenced by the control unit S via the circuit 53. The further elements shown correspond to the ones in the design example described with reference to the Fig. 1 and thus are not discussed in more detail here. In the Fig. 3 a further embodiment is shown in which a pair of take-offrolls 11 is arranged adjoining the take-off device 10. The rotational speed of this pair of rolls is monitored by a sensor 12. In this arrangement also a sensor 62 monitoring the rotational speed is co-ordinated to the pair of take-in rolls 24 of the drafting system 30 and is connected with the control unit S via the circuit 63. The lay-out of the storage device 14 corresponds to the one described already for the embodiment according to the Fig. 2. As long as no regulating action is required (unchanging linear density) the ratio of the rotational speeds of said pairs of rolls (11, 24) emains constant. If drifting of the fibre sliver mass in one direction or in the other is detected by the measuring device 70 a regulating action is effected in such a manner that the rotational speed of the intake rolls 24 is adapted. Thus also the ratio of the rotational speeds of the pairs of rolls 11 and 24 changes owing to which a control signal is generated by the control unit S in function of the change which changes, or overrides respectively, the base rotational speed of the the drafting system 3, and of the motor M2 respectively, in such a manner that, as described for the arrangement described with reference th the Fig. 2, the regulating action is compensated for. The further elements,and control systems respectively, correspond to the embodiment according to the Fig. 1 and thus are not discussed again in more detail here. The compensation for the regulating action, effected by overriding the base rotational speed of the drafting system 30, essentially concerns the long term mass variations only and not the short term ones which are not very important and, considered over time, level themselves out. In the Fig. 4 an embodiment is shown in which two cards 1a, 1b are operating in parallel side by side. These cards also are equipped with feed rolls 6a, 6b, licker-in 3a, 3b, main drum 2a, 2b und take-off roll 4a, 4b. The drive of the take-off rolls 4a and 4b is indicated schematically with 75, and 46 respectively, which are connected with the control unit S via a control circuit L8, and L9 respectively. Also the drive 20a, and 20b respectively, of the feed rolls 6a, 6b are connected with the control unit S via the. control circuits L7', and 7" respectively. In order to render feasible the co-ordination of the two cards 1 a, 1 b i.e. the drive 46 of the take-off roll 4b operates as a slave of the drive 75 of the take-off roll 4a which operates as the master drive. The fibre slivers Fa, and Fb respectively, delivered by the card 1a, and the card 1b respectively, each pass through a sensor device 10a, and 10b respectively, where their mass is scanned, ubsequently the fibre slivers Fa and Fb each are transferred into a sag storage device 11a, and 11b respectively. In these storage devices sensors 01, U1 and 02, U2 are arranged for scanning the filling level, or the amount of sagging of the fibre sliver loops. In this arrangement the sensors 01, 02 scan an upper position and the sensors U1, U2 a lower position of the fibre sliver loop. Between the respective upper sensor and the corresponding lower sensor the tolerance band extends within which the position of the fibre sliver loop can move freely without triggering a regulating action. Arrangement of a sensor for continuous scanning also could be envisaged. The sensors 01, U1 and 02, U2 are connected with the control unit S via the circuits L10, and L11 respectively, Upon leaving the respective sliver storage devices 11a, 11b the two fibre slivers Fa and Fb are joined into one single fibre sliver FZ. This fibre sliver FZ subsequently is guided past a sensor 17 which scans the mass variations in the fibre sliver FZ. The fibre sliver FZ scanned by the sensor 17 subsequently is transferred into the regulating drafting system 83. The values measured by the sensor 17 are transmitted to the control unit S via the circuit L3. The drafting system 83 in the example shown consists of three pairs of rolls 84, 85 and 86 arranged in series, in which arrangement the intake pair of rolls 84 is driven at a variable rotational speed for levelling out mass variations in the fibre sliver. The pair of delivery rolls 86 is driven by a main motor 65 and a gear train 26 arranged subsequently at a constant rotational speed. As indicated schematically by the drive train 27 also the intermediate pair of rolls 85 is driven at a constant rotational speed the ratio of which to the rotational speed of the delivery rolls 86 arranged subsequently is constant. According to the pre-set ratio of rotational speeds a constant draft is effected between the pairs of rolls 85 and 86. The motor 65 is controlled via an inverter 84 and via the circuit L6 connecting the control unit S and the motor 65. A differential gear 28 is driven via a drive train 92 and drives the pair of intake rolls 84 via the drive train 31. The drive of the differential gear 28 can be overriden by a regulating motor 29 which is controlled via an inverter (not shown) and via the cicrcuit L5 from the control unit S. This overriding is effected based on the signals transmitted from the sensor 17which are compared to a desired value pre-set in the control unit S. Downstream from the regulating drafting system 83 a sliver depositing device or coiler is arranged using which the fibre sliver F1 delivered by the drafting system after passing through a pair of calender rolls 34 and a coiler gear T is deposited in a sliver can K. The can K in this arrangement is placed on a driven can turntable (not shown) which rotates the can during the filling process. The can turntable, the calender rolls 34 and the coiler gear are driven via the drive train 98 by a gear arrangement 96. The gear 96 in turn is driven via the permanent drive connection of the gear arrangement 26, shown schematically, which is driven by the main motor 65. From this arrangement it can be seen that the pair of delivery rolls 86 is permanently coupled with the drive elements of the sliver depositing device or coiler KA directly via the gear arrangement 26. This signifies that if the gear arrangement 26 is driven at a lower speed by the motor 65 the base rotational speed of the pairs of rolls 84, 85 and 86 is lowered and also at the same time the rotational speed of the calender rolls 34, of the coiler gear T and of the can turntable of the sliver depositing or coiler device KA. As indicated schematically a mixed signal MS is generated from the signals obtained from the sensors 10a and 10b in the control unit S which is compared to a pre-set desired value.The control signal SS resulting from this comparison is applied for influencing the pre-set base rotational speed of the motor 65. In the following the function modes of the devices is discussed in more detail: At the beginning of the processing (start-up phase) the base rotational speed of the drafting system is co-ordinated, or adapted respectively, to the rotational speed of the take-off roll 4a. Only after the nominal operating speed is attained the process of overriding the base rotational speed becomes operable. The fibre slivers Fa and Fb supplied by the cards 1a and 1b are scanned by the sensors 10a and 10b and the corresponding measured values (mass) are transmitted to the control unit S where a mixed signal MS is generated. This mixed signal is compared toa pre-set desired value from which comparison a control signal results if the value measured deviates from the pre-set value. This control signal is transmitted to an inverter 94 which via the circuit L6 adapts the rotational speed of the motor 65 and thus also adapts the base rotational speed of the drafting system unit as well as of the sliver depositing or coiler device KA. It is to be noted that the long term mass deviations measured by the sensors 10a and 10b at the same time also are used for controlling the drive of the drive arrangements 20a and 20b of the feed rolls 6a and 6b of the cards 1a, 1b. The drive arangements here are connected to the control unit S via the circuits L7' and L7". Upon leaving the sensors 10a and 10b the fibre slivers Fa and Fb are transferred into the storage devices 11a ans 11b in which the slivers can sag and where they are scanned by the sensors 01, 02, and U1, U2 respectively. If the respective fibre sliver loop is located between the upper and the lower sensor, no additional control impulse is generated. As soon as e.g. the sensor U2 indicates that the loop formed by the fibre sliver Fb is sagging too much, the direct co-ordination of the drive 46 of the take-off roll 4b is overridden by the drive 75, which acts as the master drive, and rotational speed of the roll 4b is reduced. As after this action the fibre sliver loop moves back into the tolerance band between 02 and U2, the control coupling between the drives 65 and 46 is deactivated again. If the fibre sliver loop does not return into the tolerance band, a disturbance must have occurred, and the whole system is switched off. Similarly the control action is effected in the storage device 11a in which arrangement, if the fibre sliver loop is located outside the tolerance band between the sensors U1 and 01 over too long a time period, the system also is switched off as occurrence of a disturbance is to be assumed. The fibre slivers leaving their respective storage devices are joined into a common fibre sliver FZ before entering a measuring device 17 arranged subsequently. In the measuring device 17 the mass variations are measured and the corresponding signal is transmitted via the circuit 3 to the control unit S. Based on a comparison of the measured value and the pre-set desired value a corresponding signal is transmitted via the circuit L5 to the regulating motor 29 which via the regulating gear arrangement 28 adapts the rotational speed of the intake rolls 84 for levelling out the mass variations. Thus the draft between the pairs of roll 84 and 85 is changed. The draft between the pairs of roll 85 remains constant. The fibre sliver F1 drafted in the manner described is delivered by the drafting system unit and via the calender rolls 34 and the coiler gear T is coiled into a can K. For the structure of the fibre arrangement in the sliver it proves advantageous if the total draft applied is chosen greater than 3, as the trailing fibre hooks generated in the take-off process of the fibres on the card are straightened out partially in the drafting process which beneficially influences the subsequent processing steps. By pre-controlling the base rotational speed of the drafting system unit effects caused by a later regulating action at the drafting system unit can be compensated for ahead of time in such a manner that the regulating action, in particular for levelling out long term mass deviations, is to be taken care of not just by the respective fibre sliver storage device only. Thus over-sized lay-out of the fibre sliver storage device can be dispensed with. This compensation is discussed in more detail in the following with reference to the Fig. 3: Starting out from a base or operating rotational speed U1 at the time moment T1 a drift is detected by means of the sensors 10a, 10b of the measured value of the mass m exceeding the tolerance band To. If the drift of the mass m at the time moment T1 would occur without any action influencing the base rotational speed the process would develop as follows: Due to the lower mass supplied to the drafting system 83 the draft between the pairs of rolls 84 and 85 must be reduced. This signifies that the rotational speed of the pair of take-in rolls 84 is increased via the regulating motor 29 and the differential gear; and correspondingly the draft between the pairs of rolls 84 and 85 is reduced as the rotational speed of the pair of rolls 85 remains constant. Due to the reduction of the rotational speed of the intake pair of rolls 84 also the input speed of the fibre sliver F supplied is diminished. As the card, or the take-off roll respectively, is driven at constant speed the original delivery speed of the fibre sliver from the card remains constant. The difference thus created between the delivery speeed of the card and the changed intake speed of the fibre sliver at the drafting system 83 is taken care of by the fibre sliver storage device 11 a,and 11b respectively. This signifies the excess amount of fibre sliver F fills the fibre sliver storage device 11 a, and 11 b respectively, until the same ratios between the delivery speed at the card and the intake speed at the drafting system again are prevailing. Such levelling than can be effected again as soon as the regulating action at the feed roll 6a, 6b exerts its influence at the card delivery. If these mass deviations occur alternatingly upward, and downward respectively, the filling level of the sliver storage devices 11a, 11 b is not influenced much. The sliver storage dvices 11a, 11b must offer sufficient capacity. If however, these mass deviations occur at regular intervals or at random intervals and essentially in one and the same direction, the capacity of the buffer storage devices 11a, 11b soon reaches its limits. In order to avoid these disadvantages and in order to keep the capacity of the sliver storage device to a minimum, an action, as claimed according to the present invention, on the base rotational speed of the base motor 65 is effected. As soon as, e.g. at a moment in time T1, the mass deviation deteceted by tha sensors 10a, 10b exceeds a pre-set tolerance band To also the rotational speed of the motor 65 is adapted after a time lag t. From the upper diagram it can be seen that the mass diminishes and correspondingly the draft in the drafting system 83 is to be reduced also which is effected by an increase of the rotational speed of the pair of intake rolls 84. If now, as shown in the lower diagram according to the Fig. 3, the base rotational speed of the motor 65 is lowered to U2, the increase in rotational speed relative to he pair of rolls 85, effected via the regulating motor 29, is compensated for almost completely. This can be seen in particular from the two lower curves shown in the Fig. 3, the lower curve showing the change in rotational speed of the pair of intake rolls 84 elative to a constant rotational speed of the pair of rolls 85. It can be seen from this illustration that the decrease in mass detected in the fibre sliver delivered at the time moment Ti by the sensors 10a, 10b causes an increase in the rotational speed U14 of the roll 84 relative to the roll 85 in such a manner that this thin place is levelled out by reducing the draft. If the fibre sliver loop still is located within a pre-detemined tolerance band, no additional control signal for further influencing the base rotational speed is generated. By simultaneously reducing the the base rotational speed U1 of the motor 65 this change in rotational speed of the roll 84 is compensated for approximately, i.e. the rotational speed level of the drafting system 83 as a whole is lowered evenly owing to the drive co-ordination in such a manner that in spite of the change in the ratio of the rotational speeds between the pairs of rolls 84 and 85 the current rotational speed of the pair of intake rolls is re-established at about the value which had prevailed before the regulating action. Owing to this arrangement it is rendered feasible that the intake speed of the fibre sliver FZ also after a regulating action effected and after a change in the ratio of the rotational speeds remains at about the same level. Owing to this arrangement the fibre sliver storage devices 11a, 11 b are levelling out short term regulating actions whereaas the long term deviations are leevelled out by changes in the base rotational speed of the motor 65. The sensors U1, 01, U2, 02 in this arrangement serve as an additional auxiliary monitoring device. For better clarity of the diagram in the curve of the roll 84 illustration of the peaks caused by short term regulating actions was dispensed with. Such short period regulating actions as a rule oscillate up and down about the curve shown. Due to the lowering of the base rotational speed also the rotational speeds of the drive elements of the sliver depositing or coiler device are lowered synchronuously in such a manner that the ratio of rotational speeds between the delivery roll 86 and the calender rolls 34 is maintained constant. This off-setting of the long term drifts in the fibre mass can be effected relatively gently and slowly in such a manner that co-ordinating the rotational speeds of the relatively inert elements of the sliver depositing or coiling device KA does not present problems. Using the proposed arrangement according to the present invention on one hand long term deviations in the fibre mass timely can be reacted on with the help of sensor devices known already and on the other hand the fibre sliver storage device required for the regulation at the intake side of he drafting system can be kept to minimum capacity. A further aspect of the present invention concerns the improvement of the degree of fibre orientation, and the reduction in the number of hooked fires (fibre hooks) in the card sliver. The term "card sliver" in this context signifies a fibre sliver delivered to a sliver depositing or coiler device arranged downstream from the card. The importance of the degree of fibre orientation and the problems arising from the occurrence of fibre hooks in the card have been described in the volume "Verkurzte Baumwollspinnerei; Faserband-Spinnverfahren" (Abreviated Cotton Spinning; Fibre Sliver Spinning"), 1965, edited by "Zeitschrift fur die gesamte Textilindustrie" ("Review of the Textile Industry") authored by Prof. Dr. W. Wegener and Dr. H. Peuker (pages 82 ff, compare pages 87 through 97 in particular). From this study it becomes clear that application of a drafting system for improving the degree of fibre orientation in card slivers is known (Pages 87/88: Chapter "Kardenband-Verzugsaggregate" ("Card Sliver Drafting Devices"), compare also page 72 - "Graf-Optima Kardenband-Vergleichmassi-gungsaggregat" ("Graf-Optima Card Sliver Evener Device")). In the meantime further proposals for application of a drafting system at the card delivery have been published (See e.g. among othes US-C-4'100'649; US-C-3'703'023; Textile Asia, June1989, p. 20; CH-C-462'682; US-C-4'768'262; US-C-5'152 033; US-C-4'947'947; US-C-5'400'476; US-C-5,274,883; US-C-5'018248; DE-A-2'230'069; EP-A-512'683). An original Japanese Publication (JP OS 51-2 published 1976; Applied for by Fuji Seiko KK) describes a drafting system on the card performing a drafting process applying a draft ratio ranging from 1.1 to 2. Since the publication of the volume cited above interest in the application of direct card sliver spinning processes (without intermediate drawframe passages) has spread further as a spinning method of such type has been favoured by the success of the rotor spinning method (from 1970 on) - compare DE-A-4'047719. A newer proposal in this direction can be found also in EP-A-544'426 where a draft ratio ranging from 6 to 8 is proposed, and even higher draft ratios (12 or even 30) are mentioned. Notwithstanding such proposals direct card sliver spinning (wihout a drawframe passage) thus far has not been accomplished successfully, even using the rotor spinning process. Expressed in other words, it is known up to now that a card sliver is deposited (in a can), and to take off the fibre sliver at least once (from a can) and draft it in order to improve the degree of fibre orientation, whereupon the fibres (possibly upon further processing steps) can be spun. In such drafting processes no overall reduction in linear density of the material creeled is aimed at- e.g. six fibre slivers being joined into a web which subsequently is subject to a draft of six. The second aspect of the present invention provides a method of forming a card sliver, where a card web is condensed into a fibre sliver, the fibre sliver is drafted and the drafted sliver is deposited, characterized in that the fibre sliver in the drafting process is suject to a draft high enough to significantly increase the degree of fibre orientation, and to lower the proportion hooked fibres substantially. This aspect of the present invention provides a corresponding apparatus with a dafting system to be arranged between the sliver forming device and the sliver depositing or coiler device of a card, characterized in that the drafting system can generate a draft high enough in such a manner that the degree of fibre orientation is significantly inceased, and the proportion of hooked fibres is substantially lowered. In particular the fibre sliver drafting process (e.g. by means of said drafting system) being performed before the depositing process can be used for reducing the proportion of trailing hooks significantly (compare the volume "Verkurzte Spinnerei" ("Abreviated Spinning"), page 90). For the purpose mentioned it proves advantageous to subject the fibre sliver to a draft at a draft rato exceeding 2 and preferentially exceeding 3. If possible a draft ratio of 5 to 6 should be applied which, however, rarely can be realised between the card delivery and the subsequent sliver depositing or coiler device without causing disturbances in the running properties of the fibre sliver. In order to render such high draft ratios feasible between the sliver forming device and the sliver depositing or coiler device, the sliver forming device preferrably should generate a fibre sliver of high linear density (great mass), e.g. of at least 8 ktex and preferentially of 10 ktex or even more (e.g. 12 ktex). In order to achieve this, cards of a relatively large working width preferentially are applied, of e.g. of more than 1200 mm. This can be achieved using a machine according to our EP-Patent Application No. 98810'088.9. The complete contents of said EP-Application thus is considered an integral part of the present description. The (EP-Application very probably will be published on September 23, 1998 under the No. 86*153. Alternative solutions not requiring large cards have been described in EP-A-627'509 and US-C-5'535'488. The linear density of the sliver after the drafting system can be e.g. 3 to 5 ktex. The delivery speed of the drafting system can e.g. exceed 400 m/min. Preferentially a drafting system of such type is arranged on the sliver depositing or coiler device (Compare the volume "Verkurzte Baumwollspinnerei" (Abreviated Cotton Spinning"), page 72 and the patent CS-98'399 mentioned therein) in which arrangement the fibre sliver delivered by the drafting system can be deposited as soon as possible (without passing along an extended transporting path). The second aspect of the present invention correspondingly provides a method according to which a card web is condensed into a fibre sliver and is drafted, a draft of at least 2 and preferentially of more than 3 being applied before the sliver is deposited. Expressed in other words the present invention under this aspect provides a card with a fibre sliver forming device, a sliver depositing or coiler device and with a drafting system arranged between the fibre sliver forming device and the sliver depositing or coiler device for generating a draft higher than 2 and preferentially higher than 3. The drafting system can be laid out as an evening aggregate, i.e. it can be laid out for generating a controlled variable draft which, however, is not of vital importance for the present invention. Changes in the draft ratio will cause corresponding changes in the degree of fibre orientation. The card itself thus advantageously can be laid out as an evening aggregate (e.g. according to EP-A-271'115) in which arrangement the adjoining drafting system is conceived for enhancing the degree of fibre orientation. A regulating drafting system according to the second aspect of the present invention preferentially is laid out for a total draft GV (between the pair of intake rolls and the pair of delivery rolls) of more than 2 and preferably of 3 to 6. If the drafting system is not provided with a pre-drafting zone, which is not rrelevant for the present invention, the average draft in the regulated (variable) drafting zone can be e.g. about 2.5, and the draft applied in the other (constant) drafting zone can be e.g. about 1.1 to 1.5 and the "main draft" (in the second, variable draft zone) can be about 2.0 to 4. The linear density of the fibre sliver delivered from the drafting system preferentially is in the range of 3 to 5 ktex, and is e.g. 3.5 ktex. The drafting system is arranged preferentially directly above the coiler gear of a sliver depositing or coiler device,, e.g. as shown in DE-Gbm-296 22 923. The fibre sliver deposited into the can can be supplied directly, e.g. according to EP-A-627 509, to the open end spinning machine. The second aspect of the present invention preferentially (but not necessarily) is applied in combination with the other characteristics, described in the introduction, of the present invention. Claims 1. Drafting system (30) with a drive (M2) and a regulating device (M3, 33) for levelling out mass variations in a fibre mass (6) supplied to the drafting system by supply source (1), characterized in that at least one means (14, 55; 12, 62) is co-ordinated to the drafting system (30) for influencing the base rotational speed of the drafting system. 2. Drafting system according to the claim 1, characterized in that the means (14, 55; 12, 62) is suitable for scanning a regulating action required on the drive (33) of the drafting system for maintaining a pre-set desired value before or while the regulating action is effected. 3. Drafting system (30) according to the claims 1 oder 2, characterized in that the means (12, 62) is suitable for scanning differences between the supply speed of the supply source (1) and intake speed of the drafting system (30). 4. Drafting system (30) according to the claims 1 or 2, characterized in that the means (55) is suitable for scanning long term mass variations relative to a pre-set desired value. 5. Drafting system according to the claims 1, 2 or 3, characterized in that the means (55) comprises a fibre sliver storage device (14, 20). 6. Drafting system (30) according to the claim 5, characterized in that the fibre sliver storage device (14) is laid out as a sliver sag storage device. 7. Drafting system according to the claim 4, characterized in that the means is formed by an additional sensor (55) for scanning the fibre mass which is arranged upstream from the drafting system (30). 8. Drafting system according to the claim 7, characterized in that the sensor (55) is arranged at the delivery device (10) of a textile material processing unit (1) provided upstream from the drafting system (30). 9. Drafting system according to the claim 8, characterized in that the textile material processing unit is a card (1). 10. Drafting system according to the claim 9, characterized in that the sensor (55) additionally also is applied as a long term regulating device of the feed device (2) of the card (1). 11. Drafting system according to the claim 3, characterized in that the means is formed by a sensor device (62) for scanning the rotational speed of the regulated pair of rolls (24) of the drafting system (30) and by at least one pair of transporting rolls (11) for the fibre mass (6) in which arrangement the long term mass deviations are determined via the ratio of the rotational speeds measured. 12. Drafting system according to the claim 4, characterized in that the supply source consists of at least two cards (1a, 1b) operating side by side in parallel in which arrangement the drive (46) of the delivery device (4b) of the second card (1b) via a control device (S) is co-ordinated to the drive (75) of the delivery device (4a) of the first card (1a), and that the fibre material (Fa, Fb) delivered by the respective card is scanned by a sensor (10a, 10b) each and that a combined signal (MS) generated by the two sensors is applied for influencing the base rotational speed of the drafting system (83). 13. Drafting system according to the claim 12, characterized in that between the respective sensor (10a, 10b) and the drafting system (83) arranged downstream from a fibre sliver storage device (11a, 11b) each is arranged for the respective fibre material (Fa, Fb). 14. Drafting system according to the claim 13, characterized in that the fibre sliver storage devices (11a, 11b) each are provided with a monitoring device (01, U1, 02, U2). 15. Drafting system according to the claim 14, characterized in that the monitoring devices each are provided with sensors (01, U1, 02, U2) for monitoring the sagging of the fibre material (Fa, Fb) present in the respective storage device. 16. Drafting system according to one of the claims 12 through 15, characterized in that the control co-ordination of the drives (75, 46) of the first and of the second card can be overridden by the monitoring device (U2, 02) of the fibre sliver storage device (11 b) of the second card (1b). 17. Drafting system according to one of the claims 12 through 16, characterized in that the fibre material (Fa, Fb) is joined before entering the drafting system (83). 18. Drafting system according to one of the claims 1 through 17, characterized in that downstream from the drafting system (83, 30) a sliver depositing or coiler device is provided and that the draft effected by the drafting system unit is chosen high enough in such a manner that the degree of fibre orientation in the sliver is substantially increased, and that the proportion of hooked fibres is redced significantly. 19. Drafting system according to the claim 14, characterized in that the drafting system (83, 30) can generate a total draft of more than 2, preferentially more than 3 and e.g. of 3 to 6. 20. Drafting system according to one of the claims 1 through 19, characterized in that the supply source (1) is formed by at least one card and that the the fibre processing device is laid out for producing a fibre sliver presenting a linear density of more than 8 ktex, e.g. of 10 to 12 ktex. 21. Drafting system according to the claim 20, characterized in that the card (1) is provided with a working width of more than 1200 mm, and e.g. of 1300 to 1500 mm. 22. Drafting system according to one of the claims 1 through 21, characterized in that the drafting system (30, 83) is operating at a delivery speed of more than 400 m/min. 23. Drafting system according to one of the claims 1 through 21, characterized in that the drafting system (30, 83) is provided on the sliver depositing or coiler device (KA). 24. Drafting system with a drive and a regulating device substantially as herein described with reference to the accompanying drawings. Summary The present invention concerns a drafting system (30) with a drive (M2) provided with a regulating device (M3, 33) for levelling out mass variations in a fibre mass (6) supplied to the drafting system by a supply source (1) in which arrangement the mass variations are detected by at least one measuring sensor (70) co-ordinated to the drafting system and the corresponding signals are transmitted to a control unit (S) For eliminating problems arising in the layout of the storage units and for security reasons it is proposed that a further means (11, 12, 62, 63) is co-ordinated to the drafting system (30) which is suitable for detecting differences between the delivery speed of the supply source (1) and the intake speed of the drafting system (30) and apply it for influencing the base rotational speed of the drafting system or to detect long term mass variations from a pre-determined desired value in which arrangement these mass deviations detected are applied for influencing the base rotational speed of the drafting system.

Full Text

The present invention concerns a drafting system with a drive arrangement with a regulating device for regulating mass variations in a fibre mass supplied from a supply source to a drafting system in which arrangement the mass variations are detected by at least one measuring device co-ordinated to the drafting system and transmitted to a control unit.

The card operates at a constant (pre-settable) production rate, i.e. the fibre sliver is delivered at a pre-determined speed from the delivery arrangement. The function of a regulating drafting system imiplies that the draft be variable (controllable). Provision of a large sliver storage device between the card delivery and the drafting system intake is undesireable. Thus the delivery speed of the drafting system must be variable. This, however, creates problems concerning the drive for the sliver deposition or coiler system, the inertia of which is relatively considerable, arranged downstream from the the drafting system.

Various devices are known, e.g. from the DE-OS-19 19 929, in which arrangement between the card and a regulating the drafting system arranged subsequently a sliver storage device is arranged. This can be seen in particular in the Figures 3 and 4 of the DE-OS. Adjoining the regulating drafting system a sliver storage device is arranged driven by a separate motor. The measured values determined by the pair of measuring rolls upstream from the regulating drafting system are compared to the pre-set desired values. The resulting deviation signal serves for controlling the drive motor for the intake pair of rolls of the drafting system in order to adapt the draft ratio, and to level out thin and thick places respectively. At the same time this signal is transmitted to the control device for the drive of the fibre sliver source, or of the card respectively, in such a manner that this drive also can be adapted correspondingly. The reaction of the card however, is subject to substantially higher inertia than the drafting system. The resulting differences in the maerial delivery, and in the material intake respectively, are levelled out in the sliver storage device adjoining the card. The storage device in this arrangement is provided with sensors for scanning the contents of the storage device. Based on the contents determined by the sensors in the sliver storage device the drives of the fibre sliver source (card) and of the fibre sliver take-up device (coiler) are changed accordingly in such a manner that the contents of the fibre sliver storage device is maintained substantially constant. This adaptation of the two drives however, results in additional differences, especially as the elements of the card (e.g. the card main drum) are subject to different inertia influences other than the elements of the sliver depositing device (coiler).
Furthermore from the previously published DE-A1-44 24 490 a co-ordination of cards is known in which a storage device is co-ordinated to each card downstream and in which the card slivers delivered by the individual storage devices after passing through a drafting system are delivered to a common sliver deposition device or coiler. In order to compensate for the loss of one of he card slivers supplied to the drafting system the delivery speed of the drafting system is reduced until the missing card sliver has been re-inserted. In this arrangement a scanning sensor is co-ordinated to each individual

card sliver. Owing to the reduction in delivery speed, corresponding to the loss of one card sliver, the fibre sliver reserve for the draw frame is exhausted more slowly than in the normal operating mode at higher intake speeds. In the example shown an increase of the card delivery speed also is proposed if the fibre sliver storage device arranged downstream is depleted in excess of a pre-determined value in such a manner that the operation of the subsequent draw frame is not jeopardized. The arrangement shown is suitable for levelling out massive short term variation (loss of a sliver). Levelling out long term deviations however, is not envisaged using this arrangement, or is solved unsatisfactorily only.
For levelling out long period mass deviations in the fibre sliver delivered by the card it is proposed in DE-A1 29 12 576 that the thickness of the fibre sliver delivered by the card be measured and compared to a pre-set desired value. The signal thus determined is used in controlling the material supply device (feed roll) arranged upstream from the card. Owing to this arrangementlong period deviations in the mass of the card sliver delivered can be reacted on. Avoiding and eliminating of short wave deviations e.g. using a regulated drafting system is not envisaged in the arrangement described. The action in the control of the drive of the feed roll for compensating for long period mass deviations becomes effective, however, only after a major time delay.
The solutions proposed thus far generally provide the drafting system for levelling out short term variations in the fibre sliver. They correspondingly propose application of a measuring sensor at the intake of the drafting system.
Similar problems are encountered on other machines also, e.g. on the combing machine, if directly downstream from a textile processing unit a regulated drafting system is arranged which is driven at a regulated variable intake speed.
It thus is the goal of the present invention to propose an apparatus which eliminates the problems described above in order to create a straightforward and functioning com-

bination of a textile processing unit operating at essentially constant speed (supply source) with a subsequently arranged regulated drafting system unit.
This goal is achieved in that at least one further means is co-ordinated to the drafting system which is suitable to detect a regulating action on the drive of the drafting system required for maintaining a pre-determined desired rotational speed before or during the regulating action and to apply it for influencing the base rotational speed of the drafting system.
Owing to this arrangement the capacity of a storage device possibly required between the textile processing machine and the regulated drafting system arranged subsequently can be kept relatively small as the regulating actions are compensated for by adapting the base rotational speed of the drafting system. Furthermore a security device is created which ensures that the drive rotational speed (base rotational speed) does not drift from a base setting.
The further means preferentially is suitable to detect differences between the delivery speed of the supply source and the intake speed of the drafting system. The difference in speed results from the change in the rotational speed of the regulated roll of the drafting system.
The further means also can be suited for detecting long term mass variations relative to a pre-set desired value.
Preferentially the further means is a fibre sliver storage device which can be equipped with corresponding sensor elements. Using said sensors the differences in the transporting speed of the fibre sliver can be detected which are caused by the variable and regulated take-off speed of the intake pair of rolls of the drafting system unit on the basis of the variable filling degree in the storage device and an the base rotational speed of the drafting system can be acted upon. Thus a pre-control is effected which ensures that the degree of filling of the storage device can be kept to a low level.

The fibre sliver storage device can be laid out as a sliver sag storage device in which arrangement the sagging of the fibre sliver loop can be continuous or discontinuous.
Furthermore provision of an additional sensor is proposed for detecting the fibre mass which can be arranged directly adjoining the delivery of a textile material processing unit arranged upstream from the drafting system. Using this arrangement long term mass deviations can be detected at a very early stage and thus corresponding action upon the base rotational speed of the drafting system arranged downstream can be effected.
The textile processing unit in this arrangement can be a card in which arrangement the sensor provided at the delivery device of the card at the same time can be applied in a long term regulation of the feed device of the card.
The further means also can consist of a sensor device for scanning the rotational speed of the regulated pair of rolls of the drafting system and of at least one pair of transporting rolls for the fibre mass rotating at constant speed in which arrangement the ratio of rotational speeds serves for determining the long term mass deviation, based on which value corresponding action upon the base rotational speed of the drafting system can be effected.
As a further possibility it is proposed that the supply source consists of at least two coordinated cards arranged parrallel in which arrangement the drive of the second card via the control device is adapted to the drive of the first card, and that the fibre material delivered by the respective cards is detected by a sensor each and that the averaged signal generated by the two sensors is applied for acting upon the base rotational speed of the drafting system. In this manner on one hand synchronisation of the two cards and on the other hand the combined supply of the fibre slivers generated to a common drafting system are ensured in which arrangement fibre sliver storage devices, as proposed further, can be laid out in a small and compact arrangement.

Advantageously the fibre sliver storage devices can be equipped with a scanning device.
The scanning device for the fibre sliver storage device of the second card, the drive of which is co-ordinated to the one of the first card, or the slave card, can be applied for overriding the control link of the two card drives. This makes it feasible to compensate for short term deviations in the production of the second card. Expressed in other words the drive of the take-off roll of the second card is regulated until the fibre sliver loop in the fibre sliver storage device is brought back to within the sagging tolerance limits. This overriding action can be limited in time, i.e. in case of a longer duration of a deviation detected it is assumed a defect has occurred and the machines are brought to a standstill for inspection.
As scanning sensors sag sensors can be applied which scan the saging of the fibre slivers in the fibre sliver storage device continually or discontinuously.
It is proposed furthermore that downstream from the drafting system unit a sliver depositing device or coiler is arranged and that the draft applied in the drafting unit is so high that considerable increase of the degree of fibre orientation in the fibre sliver generated is achieved, and that the proportion of hooked fibres is substantially decreased. Notes pertaining to the drafting process before deposition of slivers can be found in the volume "Verkurzte Baumwollspinnerei (Abreviated Cotton Spinning)" by Prof. Dr. Ing. Walther Wegener - Monchengladbach 1965. These notes are referred to in more detail in the following.
It is assumed that the draft ratio chosen is higher than 2, and preferrably ranges between 3 and 6. This should additionally ensure that a fibre sliver of high quality structure is formed which beneficially influences in particular the subsequent processing steps.

In order to render feasible such a high draft ratio between the fibre sliver forming device and the sliver deposition or coiler device the fibre sliver forming device preferentially should generate a fibre sliver of low finness (or high linear density respectively), e.g. of at least 8 ktex and preferably 10 ktex or even more (e.g. 12 ktex). In order to render this feasible a relatively large working width of the card preferentially is chosen, e.g. exceeding 1200 mm. This can be realised using a machine according to our EP patent application No. 866 153. The whole contents of said EP application thus is considered as an integral part of the present description.
Alternative solutions not requiring wide cards have been described in EP-A-627 509 and US-C-5'535'488.
The linear density of the sliver after the drafting system can be e.g. 3 to 5 ktex. The delivery speed at the delivery of the drafting system can e.g. exceed 400 m/min. Preferentially a drafting system of such type is provided arranged on the sliver depositing or coiler device (compare the volume "Verkurzte Baumwollspinnerei (Abreviated Cotton Spinning)" p. 72 and the CS-Patent 98 939 mentioned therein) in such a manner that the fibre sliver delivered by the drafting system is deposited as soon as possible (without being transported oyer a long path).
Furher advantages of the present invention are described in more detail in the following with reference to illustrated design examples. It is shown in the:
Fig.1 a schematic side view of an inventive arrangement,
Fig.2 a further embodiment according to the Fig. 1,
Fig.3 an additional further embodiment according to the Fig. 1,
Fig.4 a schematic top view of an arrangement with two cards according to the present invention, and in the

Fig.5 a schematic diagrammatic view of the mass of a card sliver produced plotted in combination of the diagram of the adapted rotational speed of the drafting system.
In the Fig. 1 a card 1 is shown schematically which is supplied with fibre material via a feed chute 3 and via a feed roll 2 arranged adjacent to it. The fibre material is taken over by the main drum 4 and is processed in co-operation with carding elements not shown. The carded material is taken off the main drum 4 by a take-off roll 5 and is transferred to a take-off device 10 indicated schematically. From this take-off device 10 the fibre sliver 6 formed there is transferred in the transporting direction F to a sag storage device 14 equipped with a pair of take-in rolls15 and with a pair of delivery rolls 16. The degree of sliver sagging (fibre sliver loop FS) is scanned by a column-type sensor 20 provided with a series of sensors arranged along a column. Using this arrangement any position of the fibre sliver loop can be detected precisely. The sensor signals are transmitted via the circuit 21 to a control unit S.
From this control unit S the drive motor M1 of the take-off roll 5 is controlled via the control circuit 7.
The fibre sliver 6 delivered by the storage device 14 passes through a measuring device 70 which is laid out in the form of a pair of feeler rolls. The value measured by the measuring device 70 is transmitted via the circuit 71 to the control unit S. Upon passing through the measuring device 70 the fibre sliver is transferred to the drafting unit 30 formed by the pairs of rolls 24 and 25 between which it is drafted.
The base drive of the drafting unit 30 is effected by the Motor M2 which is controlled via the circuit 40 by the control unit S.
In practical application the motor M1of the take-off roll 5 in this arrangement is laid out as the leading or master motor to which the motor M2 is co-ordinated in its base rotati-

onal speed as a slave motor in such a manner that pre-determined drive conditions are maintained. This base rotational speed of the motor M2 can be overridden by the signals of the sensor 20 which is to be explained in more detail in the following.
The motor M2 drives a gear arrangement 32 from which a branch drive 35 extends to the delivery rolls 25 and a further branch drive 36 extends to a regulating gear arrangement (differential gear). From this regulating gear arrangement 33 the intake pair of rolls 24 is driven via the drive train 37.
The regulating actions required for levelling out mass variations (short and long term) according to the evaluation of the signals transmitted by the measuring device 70 in comparison with a pre-set desired value are effected by a regulating motor M3 which via a circuit 38 is controlled by the control unit S and which acts upon the regulating gear arrangement 33. Owing to this action the draft between the pairs of rolls 24 and 25 is changed and mass variations in the fibre sliver thus are levelled out.
The drive of the pair of measuring rolls 70 is effected via the drive train 68 which branches off from the drive path 37. In this manner the synchronous movement of the intake pair of rolls and the pair of measuring rolls 70.
Changes in the rotational speed of the intake pair of rolls 24 are acting backward, against the transporting direction F, and are taken up in the storage device 14 where the loop position FS is changed. Scanning the position of the sagging loop in this arrangement can be effected in steps in such a manner that if a certain amount of change is detected, overriding of the base rotational speed of the drive motor 2 sets in induced by the control unit S. Owing to this reduction, or increase respectively, in the base rotational speed the effect of the change in rotational speed caused by the regulating action, particularly in levelling out long term mass variations, are compensated for. The size of the storage device thus can be kept to a minimum.

As soon as the rotational speed of the intake pair of rolls 24 increases, the sag of the sliver loop SF is reduced, the delivery speed of the take-off roll 5 remaining constant. This is scanned by the sensor 20 and correspondingly the base rotational speed of the motor M2 is lowered. Thus the rotational speed of the intake pair of rolls also is lowered, the adapted draft ratio in the drafting system 30 remaining constant, in such a manner that the fibre sliver loop is brought back to its original position.
The drive of the sliver deposition device or coiler 60 arranged subsequently is permanently coupled to the drive of the drafting system unit 30, namely via the drive train 42 which branches off from the gear arrangement 32 and is connected to a gear arrangement 50.
The calender rolls 47, the coiler gear 48 and the can turntable 49 are driven by the gear arrangement via the gear train 51 which is shown schematically.
Between the pair of rolls 25 and the pair of calender rolls 47 a further scanning sensor 44 is arranged which via the circuit 45 is connected with the control unit S. This arrangement serves for the final control of the linear density of the fibre sliver the machine being stopped if the linear density exceeds a pre-determined tolerance field over a pre-determined period of time.
The fibre sliver passes via the calender rolls 47 and via the coiler gear 48 is deposited in coils into a sliver can K which is rotated by the can turntable while the sliver is being deposited.
In the Fig. 2 an arrangement is shown in which adjoining the take-off device 10 a pair of measuring rolls 55 is arranged which via the circuit 56 is connected with the control unit S. This measuring device 55 scans essentially the long term mass variations (Drifting of the fibre sliver linear density). The signal given off by this measuring device 55 is compared to a pre-set desired value in the control unit S and a corresponding controlling signal is generated which is used for overriding the base rotational speed of the motor

M2. Owing to this arrangement a subsequent regulating action in the drafting system 30 can be reacted on early for maintaining a constant level of the position of the fibre sliver loop in the storage device.
The storage device 14 in this arrangement is provided with two sensors S1 and S2 merely which are triggered only if the position of the fibre sliver loop FS exceeds predetermined tolerance limits. Such occurences are caused a rule by a disturbance, and the machine (plant) is switched off. The signal given off by the measuring device 55 additionally is used for regulating the drive motor MS of the feed roll of the card 1 for levelling out a drift in linear density aliready at the card. The motor MS is influenced by the control unit S via the circuit 53.
The further elements shown correspond to the ones in the design example described with reference to the Fig. 1 and thus are not discussed in more detail here.
In the Fig. 3 a further embodiment is shown in which a pair of take-offrolls 11 is arranged adjoining the take-off device 10. The rotational speed of this pair of rolls is monitored by a sensor 12. In this arrangement also a sensor 62 monitoring the rotational speed is co-ordinated to the pair of take-in rolls 24 of the drafting system 30 and is connected with the control unit S via the circuit 63.
The lay-out of the storage device 14 corresponds to the one described already for the embodiment according to the Fig. 2.
As long as no regulating action is required (unchanging linear density) the ratio of the rotational speeds of said pairs of rolls (11, 24) emains constant. If drifting of the fibre sliver mass in one direction or in the other is detected by the measuring device 70 a regulating action is effected in such a manner that the rotational speed of the intake rolls 24 is adapted. Thus also the ratio of the rotational speeds of the pairs of rolls 11 and 24 changes owing to which a control signal is generated by the control unit S in function of the change which changes, or overrides respectively, the base rotational

speed of the the drafting system 3, and of the motor M2 respectively, in such a manner that, as described for the arrangement described with reference th the Fig. 2, the regulating action is compensated for.
The further elements,and control systems respectively, correspond to the embodiment according to the Fig. 1 and thus are not discussed again in more detail here.
The compensation for the regulating action, effected by overriding the base rotational speed of the drafting system 30, essentially concerns the long term mass variations only and not the short term ones which are not very important and, considered over time, level themselves out.
In the Fig. 4 an embodiment is shown in which two cards 1a, 1b are operating in parallel side by side. These cards also are equipped with feed rolls 6a, 6b, licker-in 3a, 3b, main drum 2a, 2b und take-off roll 4a, 4b. The drive of the take-off rolls 4a and 4b is indicated schematically with 75, and 46 respectively, which are connected with the control unit S via a control circuit L8, and L9 respectively. Also the drive 20a, and 20b respectively, of the feed rolls 6a, 6b are connected with the control unit S via the. control circuits L7', and 7" respectively. In order to render feasible the co-ordination of the two cards 1 a, 1 b i.e. the drive 46 of the take-off roll 4b operates as a slave of the drive 75 of the take-off roll 4a which operates as the master drive.
The fibre slivers Fa, and Fb respectively, delivered by the card 1a, and the card 1b respectively, each pass through a sensor device 10a, and 10b respectively, where their mass is scanned, ubsequently the fibre slivers Fa and Fb each are transferred into a sag storage device 11a, and 11b respectively. In these storage devices sensors 01, U1 and 02, U2 are arranged for scanning the filling level, or the amount of sagging of the fibre sliver loops. In this arrangement the sensors 01, 02 scan an upper position and the sensors U1, U2 a lower position of the fibre sliver loop. Between the respective upper sensor and the corresponding lower sensor the tolerance band extends within which the position of the fibre sliver loop can move freely without triggering a regulating

action. Arrangement of a sensor for continuous scanning also could be envisaged. The sensors 01, U1 and 02, U2 are connected with the control unit S via the circuits L10, and L11 respectively,
Upon leaving the respective sliver storage devices 11a, 11b the two fibre slivers Fa and Fb are joined into one single fibre sliver FZ. This fibre sliver FZ subsequently is guided past a sensor 17 which scans the mass variations in the fibre sliver FZ. The fibre sliver FZ scanned by the sensor 17 subsequently is transferred into the regulating drafting system 83. The values measured by the sensor 17 are transmitted to the control unit S via the circuit L3.
The drafting system 83 in the example shown consists of three pairs of rolls 84, 85 and 86 arranged in series, in which arrangement the intake pair of rolls 84 is driven at a variable rotational speed for levelling out mass variations in the fibre sliver. The pair of delivery rolls 86 is driven by a main motor 65 and a gear train 26 arranged subsequently at a constant rotational speed. As indicated schematically by the drive train 27 also the intermediate pair of rolls 85 is driven at a constant rotational speed the ratio of which to the rotational speed of the delivery rolls 86 arranged subsequently is constant. According to the pre-set ratio of rotational speeds a constant draft is effected between the pairs of rolls 85 and 86. The motor 65 is controlled via an inverter 84 and via the circuit L6 connecting the control unit S and the motor 65. A differential gear 28 is driven via a drive train 92 and drives the pair of intake rolls 84 via the drive train 31. The drive of the differential gear 28 can be overriden by a regulating motor 29 which is controlled via an inverter (not shown) and via the cicrcuit L5 from the control unit S. This overriding is effected based on the signals transmitted from the sensor 17which are compared to a desired value pre-set in the control unit S.
Downstream from the regulating drafting system 83 a sliver depositing device or coiler is arranged using which the fibre sliver F1 delivered by the drafting system after passing through a pair of calender rolls 34 and a coiler gear T is deposited in a sliver can K. The can K in this arrangement is placed on a driven can turntable (not shown)

which rotates the can during the filling process. The can turntable, the calender rolls 34 and the coiler gear are driven via the drive train 98 by a gear arrangement 96. The gear 96 in turn is driven via the permanent drive connection of the gear arrangement 26, shown schematically, which is driven by the main motor 65. From this arrangement it can be seen that the pair of delivery rolls 86 is permanently coupled with the drive elements of the sliver depositing device or coiler KA directly via the gear arrangement 26. This signifies that if the gear arrangement 26 is driven at a lower speed by the motor 65 the base rotational speed of the pairs of rolls 84, 85 and 86 is lowered and also at the same time the rotational speed of the calender rolls 34, of the coiler gear T and of the can turntable of the sliver depositing or coiler device KA.
As indicated schematically a mixed signal MS is generated from the signals obtained from the sensors 10a and 10b in the control unit S which is compared to a pre-set desired value.The control signal SS resulting from this comparison is applied for influencing the pre-set base rotational speed of the motor 65. In the following the function modes of the devices is discussed in more detail:
At the beginning of the processing (start-up phase) the base rotational speed of the drafting system is co-ordinated, or adapted respectively, to the rotational speed of the take-off roll 4a. Only after the nominal operating speed is attained the process of overriding the base rotational speed becomes operable. The fibre slivers Fa and Fb supplied by the cards 1a and 1b are scanned by the sensors 10a and 10b and the corresponding measured values (mass) are transmitted to the control unit S where a mixed signal MS is generated. This mixed signal is compared toa pre-set desired value from which comparison a control signal results if the value measured deviates from the pre-set value. This control signal is transmitted to an inverter 94 which via the circuit L6 adapts the rotational speed of the motor 65 and thus also adapts the base rotational speed of the drafting system unit as well as of the sliver depositing or coiler device KA.
It is to be noted that the long term mass deviations measured by the sensors 10a and 10b at the same time also are used for controlling the drive of the drive arrangements

20a and 20b of the feed rolls 6a and 6b of the cards 1a, 1b. The drive arangements here are connected to the control unit S via the circuits L7' and L7".
Upon leaving the sensors 10a and 10b the fibre slivers Fa and Fb are transferred into the storage devices 11a ans 11b in which the slivers can sag and where they are scanned by the sensors 01, 02, and U1, U2 respectively. If the respective fibre sliver loop is located between the upper and the lower sensor, no additional control impulse is generated. As soon as e.g. the sensor U2 indicates that the loop formed by the fibre sliver Fb is sagging too much, the direct co-ordination of the drive 46 of the take-off roll 4b is overridden by the drive 75, which acts as the master drive, and rotational speed of the roll 4b is reduced. As after this action the fibre sliver loop moves back into the tolerance band between 02 and U2, the control coupling between the drives 65 and 46 is deactivated again. If the fibre sliver loop does not return into the tolerance band, a disturbance must have occurred, and the whole system is switched off.
Similarly the control action is effected in the storage device 11a in which arrangement, if the fibre sliver loop is located outside the tolerance band between the sensors U1 and 01 over too long a time period, the system also is switched off as occurrence of a disturbance is to be assumed.
The fibre slivers leaving their respective storage devices are joined into a common fibre sliver FZ before entering a measuring device 17 arranged subsequently.
In the measuring device 17 the mass variations are measured and the corresponding signal is transmitted via the circuit 3 to the control unit S. Based on a comparison of the measured value and the pre-set desired value a corresponding signal is transmitted via the circuit L5 to the regulating motor 29 which via the regulating gear arrangement 28 adapts the rotational speed of the intake rolls 84 for levelling out the mass variations. Thus the draft between the pairs of roll 84 and 85 is changed. The draft between the pairs of roll 85 remains constant.

The fibre sliver F1 drafted in the manner described is delivered by the drafting system unit and via the calender rolls 34 and the coiler gear T is coiled into a can K.
For the structure of the fibre arrangement in the sliver it proves advantageous if the total draft applied is chosen greater than 3, as the trailing fibre hooks generated in the take-off process of the fibres on the card are straightened out partially in the drafting process which beneficially influences the subsequent processing steps.
By pre-controlling the base rotational speed of the drafting system unit effects caused by a later regulating action at the drafting system unit can be compensated for ahead of time in such a manner that the regulating action, in particular for levelling out long term mass deviations, is to be taken care of not just by the respective fibre sliver storage device only. Thus over-sized lay-out of the fibre sliver storage device can be dispensed with. This compensation is discussed in more detail in the following with reference to the Fig. 3:
Starting out from a base or operating rotational speed U1 at the time moment T1 a drift is detected by means of the sensors 10a, 10b of the measured value of the mass m exceeding the tolerance band To. If the drift of the mass m at the time moment T1 would occur without any action influencing the base rotational speed the process would develop as follows: Due to the lower mass supplied to the drafting system 83 the draft between the pairs of rolls 84 and 85 must be reduced. This signifies that the rotational speed of the pair of take-in rolls 84 is increased via the regulating motor 29 and the differential gear; and correspondingly the draft between the pairs of rolls 84 and 85 is reduced as the rotational speed of the pair of rolls 85 remains constant. Due to the reduction of the rotational speed of the intake pair of rolls 84 also the input speed of the fibre sliver F supplied is diminished. As the card, or the take-off roll respectively, is driven at constant speed the original delivery speed of the fibre sliver from the card remains constant. The difference thus created between the delivery speeed of the card and the changed intake speed of the fibre sliver at the drafting system 83 is taken care of by the fibre sliver storage device 11 a,and 11b respectively. This signifies the excess

amount of fibre sliver F fills the fibre sliver storage device 11 a, and 11 b respectively, until the same ratios between the delivery speed at the card and the intake speed at the drafting system again are prevailing. Such levelling than can be effected again as soon as the regulating action at the feed roll 6a, 6b exerts its influence at the card delivery. If these mass deviations occur alternatingly upward, and downward respectively, the filling level of the sliver storage devices 11a, 11 b is not influenced much. The sliver storage dvices 11a, 11b must offer sufficient capacity. If however, these mass deviations occur at regular intervals or at random intervals and essentially in one and the same direction, the capacity of the buffer storage devices 11a, 11b soon reaches its limits.
In order to avoid these disadvantages and in order to keep the capacity of the sliver storage device to a minimum, an action, as claimed according to the present invention, on the base rotational speed of the base motor 65 is effected. As soon as, e.g. at a moment in time T1, the mass deviation deteceted by tha sensors 10a, 10b exceeds a pre-set tolerance band To also the rotational speed of the motor 65 is adapted after a time lag t. From the upper diagram it can be seen that the mass diminishes and correspondingly the draft in the drafting system 83 is to be reduced also which is effected by an increase of the rotational speed of the pair of intake rolls 84. If now, as shown in the lower diagram according to the Fig. 3, the base rotational speed of the motor 65 is lowered to U2, the increase in rotational speed relative to he pair of rolls 85, effected via the regulating motor 29, is compensated for almost completely. This can be seen in particular from the two lower curves shown in the Fig. 3, the lower curve showing the change in rotational speed of the pair of intake rolls 84 elative to a constant rotational speed of the pair of rolls 85. It can be seen from this illustration that the decrease in mass detected in the fibre sliver delivered at the time moment Ti by the sensors 10a, 10b causes an increase in the rotational speed U14 of the roll 84 relative to the roll 85 in such a manner that this thin place is levelled out by reducing the draft. If the fibre sliver loop still is located within a pre-detemined tolerance band, no additional control signal for further influencing the base rotational speed is generated. By simultaneously reducing the the base rotational speed U1 of the motor

65 this change in rotational speed of the roll 84 is compensated for approximately, i.e. the rotational speed level of the drafting system 83 as a whole is lowered evenly owing to the drive co-ordination in such a manner that in spite of the change in the ratio of the rotational speeds between the pairs of rolls 84 and 85 the current rotational speed of the pair of intake rolls is re-established at about the value which had prevailed before the regulating action. Owing to this arrangement it is rendered feasible that the intake speed of the fibre sliver FZ also after a regulating action effected and after a change in the ratio of the rotational speeds remains at about the same level. Owing to this arrangement the fibre sliver storage devices 11a, 11 b are levelling out short term regulating actions whereaas the long term deviations are leevelled out by changes in the base rotational speed of the motor 65. The sensors U1, 01, U2, 02 in this arrangement serve as an additional auxiliary monitoring device. For better clarity of the diagram in the curve of the roll 84 illustration of the peaks caused by short term regulating actions was dispensed with. Such short period regulating actions as a rule oscillate up and down about the curve shown.
Due to the lowering of the base rotational speed also the rotational speeds of the drive elements of the sliver depositing or coiler device are lowered synchronuously in such a manner that the ratio of rotational speeds between the delivery roll 86 and the calender rolls 34 is maintained constant. This off-setting of the long term drifts in the fibre mass can be effected relatively gently and slowly in such a manner that co-ordinating the rotational speeds of the relatively inert elements of the sliver depositing or coiling device KA does not present problems.
Using the proposed arrangement according to the present invention on one hand long term deviations in the fibre mass timely can be reacted on with the help of sensor devices known already and on the other hand the fibre sliver storage device required for the regulation at the intake side of he drafting system can be kept to minimum capacity.
A further aspect of the present invention concerns the improvement of the degree of fibre orientation, and the reduction in the number of hooked fires (fibre hooks) in the

card sliver. The term "card sliver" in this context signifies a fibre sliver delivered to a sliver depositing or coiler device arranged downstream from the card.
The importance of the degree of fibre orientation and the problems arising from the occurrence of fibre hooks in the card have been described in the volume "Verkurzte Baumwollspinnerei; Faserband-Spinnverfahren" (Abreviated Cotton Spinning; Fibre Sliver Spinning"), 1965, edited by "Zeitschrift fur die gesamte Textilindustrie" ("Review of the Textile Industry") authored by Prof. Dr. W. Wegener and Dr. H. Peuker (pages 82 ff, compare pages 87 through 97 in particular). From this study it becomes clear that application of a drafting system for improving the degree of fibre orientation in card slivers is known (Pages 87/88: Chapter "Kardenband-Verzugsaggregate" ("Card Sliver Drafting Devices"), compare also page 72 - "Graf-Optima Kardenband-Vergleichmassi-gungsaggregat" ("Graf-Optima Card Sliver Evener Device")). In the meantime further proposals for application of a drafting system at the card delivery have been published (See e.g. among othes US-C-4'100'649; US-C-3'703'023; Textile Asia, June1989, p. 20; CH-C-462'682; US-C-4'768'262; US-C-5'152 033; US-C-4'947'947; US-C-5'400'476; US-C-5,274,883; US-C-5'018*248; DE-A-2'230'069; EP-A-512'683).
An original Japanese Publication (JP OS 51-2 published 1976; Applied for by Fuji Seiko KK) describes a drafting system on the card performing a drafting process applying a draft ratio ranging from 1.1 to 2.
Since the publication of the volume cited above interest in the application of direct card sliver spinning processes (without intermediate drawframe passages) has spread further as a spinning method of such type has been favoured by the success of the rotor spinning method (from 1970 on) - compare DE-A-4'047719. A newer proposal in this direction can be found also in EP-A-544'426 where a draft ratio ranging from 6 to 8 is proposed, and even higher draft ratios (12 or even 30) are mentioned. Notwithstanding such proposals direct card sliver spinning (wihout a drawframe passage) thus far has not been accomplished successfully, even using the rotor spinning process.

Expressed in other words, it is known up to now that a card sliver is deposited (in a can), and to take off the fibre sliver at least once (from a can) and draft it in order to improve the degree of fibre orientation, whereupon the fibres (possibly upon further processing steps) can be spun. In such drafting processes no overall reduction in linear density of the material creeled is aimed at- e.g. six fibre slivers being joined into a web which subsequently is subject to a draft of six.
The second aspect of the present invention provides a method of forming a card sliver, where a card web is condensed into a fibre sliver, the fibre sliver is drafted and the drafted sliver is deposited, characterized in that the fibre sliver in the drafting process is suject to a draft high enough to significantly increase the degree of fibre orientation, and to lower the proportion hooked fibres substantially.
This aspect of the present invention provides a corresponding apparatus with a dafting system to be arranged between the sliver forming device and the sliver depositing or coiler device of a card, characterized in that the drafting system can generate a draft high enough in such a manner that the degree of fibre orientation is significantly inceased, and the proportion of hooked fibres is substantially lowered.
In particular the fibre sliver drafting process (e.g. by means of said drafting system) being performed before the depositing process can be used for reducing the proportion of trailing hooks significantly (compare the volume "Verkurzte Spinnerei" ("Abreviated
Spinning"), page 90).
For the purpose mentioned it proves advantageous to subject the fibre sliver to a draft at a draft rato exceeding 2 and preferentially exceeding 3. If possible a draft ratio of 5 to 6 should be applied which, however, rarely can be realised between the card delivery and the subsequent sliver depositing or coiler device without causing disturbances in the running properties of the fibre sliver.

In order to render such high draft ratios feasible between the sliver forming device and the sliver depositing or coiler device, the sliver forming device preferrably should generate a fibre sliver of high linear density (great mass), e.g. of at least 8 ktex and preferentially of 10 ktex or even more (e.g. 12 ktex). In order to achieve this, cards of a relatively large working width preferentially are applied, of e.g. of more than 1200 mm. This can be achieved using a machine according to our EP-Patent Application No. 98*810'088.9. The complete contents of said EP-Application thus is considered an integral part of the present description. The (EP-Application very probably will be published on September 23, 1998 under the No. 86*153.
Alternative solutions not requiring large cards have been described in EP-A-627'509 and US-C-5'535'488.
The linear density of the sliver after the drafting system can be e.g. 3 to 5 ktex. The delivery speed of the drafting system can e.g. exceed 400 m/min. Preferentially a drafting system of such type is arranged on the sliver depositing or coiler device (Compare the volume "Verkurzte Baumwollspinnerei" (Abreviated Cotton Spinning"), page 72 and the patent CS-98'399 mentioned therein) in which arrangement the fibre sliver delivered by the drafting system can be deposited as soon as possible (without passing along an extended transporting path).
The second aspect of the present invention correspondingly provides a method according to which a card web is condensed into a fibre sliver and is drafted, a draft of at least 2 and preferentially of more than 3 being applied before the sliver is deposited.
Expressed in other words the present invention under this aspect provides a card with a fibre sliver forming device, a sliver depositing or coiler device and with a drafting system arranged between the fibre sliver forming device and the sliver depositing or coiler device for generating a draft higher than 2 and preferentially higher than 3.

The drafting system can be laid out as an evening aggregate, i.e. it can be laid out for generating a controlled variable draft which, however, is not of vital importance for the present invention. Changes in the draft ratio will cause corresponding changes in the degree of fibre orientation. The card itself thus advantageously can be laid out as an evening aggregate (e.g. according to EP-A-271'115) in which arrangement the adjoining drafting system is conceived for enhancing the degree of fibre orientation.
A regulating drafting system according to the second aspect of the present invention preferentially is laid out for a total draft GV (between the pair of intake rolls and the pair of delivery rolls) of more than 2 and preferably of 3 to 6. If the drafting system is not provided with a pre-drafting zone, which is not rrelevant for the present invention, the average draft in the regulated (variable) drafting zone can be e.g. about 2.5, and the draft applied in the other (constant) drafting zone can be e.g. about 1.1 to 1.5 and the "main draft" (in the second, variable draft zone) can be about 2.0 to 4.
The linear density of the fibre sliver delivered from the drafting system preferentially is in the range of 3 to 5 ktex, and is e.g. 3.5 ktex. The drafting system is arranged preferentially directly above the coiler gear of a sliver depositing or coiler device,, e.g. as shown in DE-Gbm-296 22 923. The fibre sliver deposited into the can can be supplied directly, e.g. according to EP-A-627 509, to the open end spinning machine.
The second aspect of the present invention preferentially (but not necessarily) is applied in combination with the other characteristics, described in the introduction, of the present invention.

Claims
1. Drafting system (30) with a drive (M2) and a regulating device (M3, 33) for levelling out mass variations in a fibre mass (6) supplied to the drafting system by supply source (1), characterized in that at least one means (14, 55; 12, 62) is co-ordinated to the drafting system (30) for influencing the base rotational speed of the drafting system.
2. Drafting system according to the claim 1, characterized in that the means (14, 55; 12, 62) is suitable for scanning a regulating action required on the drive (33) of the drafting system for maintaining a pre-set desired value before or while the regulating action is effected.
3. Drafting system (30) according to the claims 1 oder 2, characterized in that the means (12, 62) is suitable for scanning differences between the supply speed of the supply source (1) and intake speed of the drafting system (30).
4. Drafting system (30) according to the claims 1 or 2, characterized in that the means (55) is suitable for scanning long term mass variations relative to a pre-set desired value.
5. Drafting system according to the claims 1, 2 or 3, characterized in that the means (55) comprises a fibre sliver storage device (14, 20).
6. Drafting system (30) according to the claim 5, characterized in that the fibre sliver storage device (14) is laid out as a sliver sag storage device.
7. Drafting system according to the claim 4, characterized in that the means is formed by an additional sensor (55) for scanning the fibre mass which is arranged upstream from the drafting system (30).

8. Drafting system according to the claim 7, characterized in that the sensor (55) is arranged at the delivery device (10) of a textile material processing unit (1) provided upstream from the drafting system (30).
9. Drafting system according to the claim 8, characterized in that the textile material processing unit is a card (1).
10. Drafting system according to the claim 9, characterized in that the sensor (55) additionally also is applied as a long term regulating device of the feed device (2) of the card (1).
11. Drafting system according to the claim 3, characterized in that the means is formed by a sensor device (62) for scanning the rotational speed of the regulated pair of rolls (24) of the drafting system (30) and by at least one pair of transporting rolls (11) for the fibre mass (6) in which arrangement the long term mass deviations are determined via the ratio of the rotational speeds measured.
12. Drafting system according to the claim 4, characterized in that the supply source consists of at least two cards (1a, 1b) operating side by side in parallel in which arrangement the drive (46) of the delivery device (4b) of the second card (1b) via a control device (S) is co-ordinated to the drive (75) of the delivery device (4a) of the first card (1a), and that the fibre material (Fa, Fb) delivered by the respective card is scanned by a sensor (10a, 10b) each and that a combined signal (MS) generated by the two sensors is applied for influencing the base rotational speed of the drafting system (83).
13. Drafting system according to the claim 12, characterized in that between the respective sensor (10a, 10b) and the drafting system (83) arranged downstream from a fibre sliver storage device (11a, 11b) each is arranged for the respective fibre material (Fa, Fb).

14. Drafting system according to the claim 13, characterized in that the fibre sliver storage devices (11a, 11b) each are provided with a monitoring device (01, U1, 02, U2).
15. Drafting system according to the claim 14, characterized in that the monitoring devices each are provided with sensors (01, U1, 02, U2) for monitoring the sagging of the fibre material (Fa, Fb) present in the respective storage device.
16. Drafting system according to one of the claims 12 through 15, characterized in that the control co-ordination of the drives (75, 46) of the first and of the second card can be overridden by the monitoring device (U2, 02) of the fibre sliver storage device (11 b) of the second card (1b).
17. Drafting system according to one of the claims 12 through 16, characterized in that the fibre material (Fa, Fb) is joined before entering the drafting system (83).
18. Drafting system according to one of the claims 1 through 17, characterized in that downstream from the drafting system (83, 30) a sliver depositing or coiler device is provided and that the draft effected by the drafting system unit is chosen high enough in such a manner that the degree of fibre orientation in the sliver is substantially increased, and that the proportion of hooked fibres is redced significantly.
19. Drafting system according to the claim 14, characterized in that the drafting system (83, 30) can generate a total draft of more than 2, preferentially more than 3 and e.g. of 3 to 6.
20. Drafting system according to one of the claims 1 through 19, characterized in that the supply source (1) is formed by at least one card and that the the fibre processing device is laid out for producing a fibre sliver presenting a linear density of more than 8 ktex, e.g. of 10 to 12 ktex.

21. Drafting system according to the claim 20, characterized in that the card (1) is
provided with a working width of more than 1200 mm, and e.g. of 1300 to 1500 mm.
22. Drafting system according to one of the claims 1 through 21, characterized in that
the drafting system (30, 83) is operating at a delivery speed of more than 400
m/min.
23. Drafting system according to one of the claims 1 through 21, characterized in that
the drafting system (30, 83) is provided on the sliver depositing or coiler device (KA).
24. Drafting system with a drive and a regulating device
substantially as herein described with reference to the accompanying drawings.

Summary The present invention concerns a drafting system (30) with a drive (M2) provided with a regulating device (M3, 33) for levelling out mass variations in a fibre mass (6) supplied to the drafting system by a supply source (1) in which arrangement the mass variations are detected by at least one measuring sensor (70) co-ordinated to the drafting system and the corresponding signals are transmitted to a control unit (S) For eliminating problems arising in the layout of the storage units and for security reasons it is proposed that a further means (11, 12, 62, 63) is co-ordinated to the drafting system (30) which is suitable for detecting differences between the delivery speed of the supply source (1) and the intake speed of the drafting system (30) and apply it for influencing the base rotational speed of the drafting system or to detect long term mass variations from a pre-determined desired value in which arrangement these mass deviations detected are applied for influencing the base rotational speed of the drafting system.

Documents:

2635-mas-1998-abstract.pdf

2635-mas-1998-claims duplicate.pdf

2635-mas-1998-claims original.pdf

2635-mas-1998-correspondence others.pdf

2635-mas-1998-correspondence po.pdf

2635-mas-1998-description complete duplicate.pdf

2635-mas-1998-description complete original.pdf

2635-mas-1998-drawings.pdf

2635-mas-1998-form 1.pdf

2635-mas-1998-form 26.pdf

2635-mas-1998-form 3.pdf

2635-mas-1998-form 4.pdf

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Patent Number

208265

Indian Patent Application Number

2635/MAS/1998

PG Journal Number

27/2007

Publication Date

06-Jul-2007

Grant Date

20-Jul-2007

Date of Filing

23-Nov-1998

Name of Patentee

MASCHINENFABRIK RIETER AG

Applicant Address

KLOSTERSTRASSE 20, CH-8406, WINTERTHUR.

Inventors:

#	Inventor's Name	Inventor's Address
1	NAF BEAT	REBACKERSTRASSE 18a, JONA.
2	FAAS JURG	OBERKAHNENSTRASSE 13, CH8450 ANDELFINGEN.
3	GRIESSHAMMER CHRISTIAN	BUTZIACKERSTRASSE 43, CH-8406, WINTERTHUR.
4	GRESSER GOTZ THEODOR	NEUMUHLESTRASSE 23, CH-8406 WINTERTHUR.

PCT International Classification Number

D01H5/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2711/97	1997-11-24	Switzerland
2	1560/98	1998-07-23	Switzerland