Title of Invention

A METHOD FOR CONTROLLING THE DRAFT OF A DRAWING SYSTEM IN A TEXTILE MACHINE, AND A TEXTILE MACHINE

Abstract A method is proposed for controlling the draft in the drawing system(5) in a textile machine (1) in which for sequential segments (AB1, …., Abn-2, ABn-1, Abn) of a fibre silver (FGzu) being supplied to the drawing system (5), an feeding sensor unit (4) upstream of the drawing system (5) takes a measurement (MLM1,….,MLMn-2,MLMn-1,MLMn) of the mass per unit length in each case; and in order to even out the mass per unit length of the incoming fibre silver (FGzu) a control adjustment is made to the draft (V) of the drawing system (5) on the basis of one of the aforementioned measurements (MLM1) as soon as the segment (AB1) associated with the aforementioned measurement (MLM1) reaches a control action point (REP) that is specified by a specified figure (RP); a modification of the specified figure (RP) for the control action point (REP) is carried out during the productive phase of the textile machine (1), where the specified figure (RP) is derived from a previously determined setting figure (ERP) and from a correction figure (RP), and where the correction figure (RP) is determined from a figure (MEG, GM, GM, SEG) corresponding to the feeding speed (EG) of the fibre silver (FGzu) being supplied to the drawing system (5) and from a figure (MLG, SLG) corresponding to the delivery speed (LG) of the fibre silver (Fgab) emerging from the drawing frame. A textile machine is also proposed.
Full Text FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)


1. TITLE OF INVENTION
A METHOD FOR CONTROLLING THE DRAFT OF A DRAWING SYSTEM IN A


TEXTILE MACHINE, AND A TEXTILE MACHINE


APPLICANT(S)
a) Name
b) Nationality
c) Address

RIETER INGOLSTADT SPINNEREIMASCHINENBAU AG
GERMAN Company
FRIEDRICH-EBERT-STRASSE 84,
85055 INGOLSTADT,
GERMANY

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

The present invention concerns a method for controlling the draft of a drawing system in a textile machine, and a textile machine in accordance with the preambles of the independent claims.
In addition to textile machines incorporating a drawing system having a draft that, while adjustable, is constant during operation, textile machines having a drawing system with a controllable draft, in other words one that can be changed in the course of operation, are known to the prior art. An important aspect of controlling the draft in a drawing system of a textile machine is the position of what is known as the control action point. The control action point is a specified location upstream of the drawing system at which a section of a fibre sliver, whose mass per unit length has been measured, is located when an adjustment is made to the draft of the drawing frame. The control adjustments are made in order to even out the mass per unit length of the fibre sliver.
The position of the control action point can, for instance, be specified as its distance from the measuring location. A specification of this type ultimately gives the distance that a specific section of the fibre sliver covers between the measuring location and the drawing location. Alternatively, the position of the control action point can be quoted as the running time that a specific section of the fibre sliver is required to travel from the measuring location to the drawing location. Both specifications are technically equivalent. It is only necessary to know the speed of the fibre sliver in order to convert between them.
Textile machines having a controllable drawing system usually incorporate a control unit that controls the draft in the drawing system. The control unit operates on the basis of a specified figure to exercise appropriate action on the drawing mechanisms in the drawing system and thereby maintain the specified control action point. A setting figure that can be set manually or automatically is usually used as the specified figure.


Setting an optimum setting figure, and thereby an optimum control action point, is crucial for the quality of the fibre sliver created by means of the drawing system. Nevertheless, it has not yet been possible to determine an optimum setting figure for the specified figure analytically. It is therefore usual to determine the setting empirically in test or adjustment runs, in which the quality of the fibre sliver emerging from the drawing system is determined for a variety of setting figures, and the setting figure that leads to the best quality is then chosen. The setting found in this way is then kept constant during operation of the textile machine and used as the specified figure until such time as the test or adjustment runs are repeated.
A method of this type for controlling the draft in the drawing field of an autoleveller drawframe is known from DE 100 41 892 Al. In the proposed method, a setting figure for the control action point is determined in a test or adjustment run prior to full operation. A variety of settings are set in sequence for this purpose, and for each setting figure tried, a number of CV values with different reference lengths of the fibre sliver leaving the drawing field are determined. The CV values found for a particular setting are added together, in order to attain a quality parameter. The quality parameters obtained from the different experimentally set setting figures are then used to create a second order polynomial, whose minimum is found by numerical procedures and is considered to be an optimum setting figure. This setting figure is then applied, and is used as the specified figure for the control action point.
A disadvantage of the method disclosed in DE 100 41 892 Al is that the operating parameters relevant when determining the specified figure in the course of preoperational test or adjustment runs only rarely match the operating parameters applying when the textile machine is in the phase of production. In other words, the specified figure determined by means of the method described above and the control action point that results from it necessarily differ from the optimum specified figure or control action points relevant to the phase of production of the textile machine.


This, in turn, generally results in a fibre sliver emerging from the drawing region with a quality that is less than optimum.
It is therefore the task of the present invention to provide a method and a textile machine that avoid these disadvantages.
The task is fulfilled by a method and a textile machine having the features of the independent patent claims.
In the method according to the invention, a modification is made to the specified figure for the control action point while the textile machine is in the phase of production, the specified figure being formed from a previously determined setting figure and from a correction figure. The correction figure is determined from a figure associated with the feeding speed of the fibre sliver being fed to the drawing system, and a figure associated with the delivery speed of the fibre sliver emerging from the drawing system.
The invention recognizes that the optimum position of the control action point depends both on the feeding speed with which the sliver is entering the drawing system and on the delivery speed of the drawing system. If the feeding speed and/or the delivery speed of the drawing system when the textile machine is operating now varies from the feeding speed or the delivery speed that were used during the test or setting run, the setting that was determined in the test or setting run is corrected by means of the correction figure so that an optimum specified figure is obtained. It is not necessary to repeat the extensive test or setting runs again. By means of the method in accordance with the invention it is possible to react to a change in the feeding speed or the delivery speed, regardless of whether the change also results in a change to the draft.
Changing the feeding and delivery speeds without changing the draft can, for instance, be necessary when the fibre sliver being supplied to the drawing system is

delivered directly from a running carder without being stored in between in a sliver can. In this case the feeding speed of the drawing system must be adapted to match the working speed of the carder. On the assumption that the mass per unit length of the fibre sliver being fed to the carder remains unchanged, the draft of the drawing system should nevertheless remain constant. For this reason, the delivery speed of the drawing system must also be adjusted. The shift in the optimum control action point that nevertheless arises can be handled by the method according to the invention.
If, however, the mass per unit length of the fibre sliver being fed to the drawing system does change, this can be compensated for by a change in the draft. The shift in the optimum control action point that arises in this case to can be handled by the method according to the invention. In general the method according to the invention makes it possible to ensure that the optimum control action point is used for any change in the feeding speed, the delivery speed or of the feeding and delivery speeds.
The modification of the specified figure and/or determination of the correction figure are favourably carried out automatically. On the one hand this reduces the work required from an operative, while on the other hand it makes it possible to react to short-term changes in the feeding and/ or delivery speeds.
The adaptation of the specified figure can be carried out under time control. It is possible, for instance, to specify a certain period of time after which a new correction figure is to be determined and the specified figure correspondingly modified. This can keep the controller resources used low. The same applies if modification of the specified figure is controlled by length, in other words when the modification is repeated after a particular length of fibre sliver fed to or delivered from the drawing system. It is also, however, possible always to carry out the adaptation whenever a specific event occurs. An event of this type could, for instance, be a change in the


feeding or delivery speed by a specific amount or percentage value. In this way it is possible to ensure that the adaptation is only carried out when it is in fact necessary.
Favourably the correction figure is calculated on the basis of a previously specified formula involving the figure that corresponds to the feeding speed and the figure that corresponds to the delivery speed. The structure of the formula and any coefficients or constants used it can, for instance, be determined on the basis of empirical figures. A formula that has once been created can be checked empirically, and, if necessary, adapted. Favourably the formula is determined at a stage prior to productive operation, so that it is immediately available for the calculation of correction figures during the phase of production. It is also, however, conceivable that the formula might be adapted during the productive phase of the textile machine.
It is particularly favourable if the correction figure can be read from a previously specified table using the figure corresponding to the feeding speed and the figure corresponding to the delivery speed. The table can be prepared by determining correction figures empirically for various pairs of figures, where in each case one corresponds to the feeding speed and one figure corresponds to the delivery speed. A table that has once been prepared can be stored, permitting it to be accessed as often as it is wanted. Because the correction figure is then found simply by reading it from the table, the computational effort required to modify the specified figure during the operating or productive phase of the textile machine is small.
Favourably the setting figure is determined in a test run making use of a parameter indicative of quality, such as the CV% value for the fibre sliver emerging from the drawing system, or a magnitude derived from that. In this way it is ensured that, in addition to the feeding and delivery speeds, the other factors that determine the optimum position of the control action point are taken into account. It is particularly the combination of the performance of a test run in order to discover a setting figure for the specified figure, and modification, with a correction figure, of the specified

figure based on the setting that has been found that ensures that the optimum control action point is always used.
Favourably the figure corresponding to the feeding speed and/or the figure corresponding to the delivery speed are standardized before the correction figure is determined. The figure corresponding to the feeding speed, for instance, can be the percentage deviation of the current feeding speed from a planned feeding speed. In this way the subsequent determination of the correction figure can be simplified. In particular, the size of a table from which correction figures are read can be kept small.
A set value for the feeding speed is favourably used as the figure corresponding to the feeding speed. The set value for the feeding speed is usually known, which yields a simple embodiment of the method. As an alternative, measurements of the feeding speed can be used; this is always advantageous if the actual value of the feeding speed differs from the set value of the feeding speed.
It is particularly favourable if a mean value is formed from a large number of set values of the feeding speed or from a large number of measurements of the feeding speed, so that the mean value can be used as the figure corresponding to the feeding speed. In this way, random variations in the set value or the measurements can be suppressed. As a result, the correction figure found is more reliable.
It is equally favourable if a set value for the delivery speed, or a measurement of the delivery speed, is used as the figure corresponding to the delivery speed.
Mean values can again be calculated in respect of the delivery speed, so that random variations in the measurements or set values can be suppressed.
If a control adjustment is made to change the draft of the drawing system on the drawing system's feeding side, the mass per unit length of the fibre sliver being

supplied to the drawing systemprovides a measure for the drawing frame's feeding speed. The reason for this is that a change in the mass per unit length automatically results in a change in the draft, and this in turn results in a change to the drawing frame's feeding speed. For this reason, the aforementioned measurement of the mass per unit length, or a mean value derived from a large number of the aforementioned measurements of the mass per unit length, can be used as the figure corresponding to the feeding speed for determining the correction figure. Similar points apply if a control adjustment as aforementioned is carried out on the delivery side. In this case a measurement of the mass per unit length, or a mean value derived from a large number of the aforementioned measurements of the mass per unit length, can be used as the figure corresponding to the delivery speed.
In a textile machine in accordance with the invention, the control equipment for adjusting the specified figure for the control action point in the productive phase of the textile machine is designed so that a previously determined setting for the specified figure can be corrected by means of a correction figure, in a process where the control equipment for automatically determining the correction figure does so on the basis of a figure corresponding to the feeding speed of the fibre sliver supplied to the drawing system and from a figure corresponding to the delivery speed of the fibre sliver emerging from the drawing frame.
The control equipment is favourably designed for automatic modification of the specified figure. As an alternative, the correction figure can be determined automatically by the control equipment, and the modification of the specified figure be carried out by an operative.
The textile machine can also be designed to execute further embodiments of the method in accordance with the invention. The advantages described above are then obtained.


Further advantages of the invention are described in the following specific embodiment examples. They show:
Figure 1 an autoleveller drawframe in accordance with the prior art;
Figure 2 an embodiment of a drawing frame in accordance with the invention,
and
Figure 3 a further embodiment of a drawing frame in accordance with the
invention.
Figure 1 shows a schematic side view of a drawing frame 1 as an example of a spinning preparation machine 1. The fibre slivers FBI, FB2, FB3, FB4, FB5, FB6 in front of the drawing frame 1 are passed in the direction of movement LR over a feed stand 2, an feeding roller unit 3, an feeding sensor unit 4, a drawing system 5, an outlet guide 6 and over a sliver depository 7.
The feed stand 2, only shown schematically, comprises a first feed stand roller 2a arranged in such a way that a first fibre sliver FBI in front of the machine can be drawn from a sliver can Kl placed by the drawing frame 1, and a second fibre sliver FB2 can be drawn from a sliver can K2 placed in an offset position. A second feed stand roller 2b is included in order to draw a third fibre sliver FB3 from a third sliver can K3 and a fourth fibre sliver FB4 from a fourth sliver can K4. A fifth fibre sliver FB5 and a sixth fibre sliver FB6 are also each drawn by another feed stand roller, not shown here, from a sliver can, also not shown. Altogether the feed stand 2 is designed to supply six fibre slivers simultaneously to the feeding roller unit 3. This should, however, merely be understood as an example, as a different number of sliver cans supplying fibre slivers can also be present.
The feed stand 2 can also be designed in such a way that it can accept an incoming fibre sliver directly from a running carder, or a number of incoming fibre slivers, each from a running carder.

The feed stand rollers 2a, 2b are driven in such a way when removing the fibre slivers FBI, FB2, FB3, FB4, FB5, FB6 that they always have the same circumferential speed.
Following the feed stand the fibre slivers FBI, FB2, FB3, FB4, FB5, FB6 are combined into a single fibre sliver FG that continues on in the direction of movement LR. For the sake of greater clarity, the fibre sliver FG prior to the drawing system 5 will be referred to as the incoming fibre sliver FGzu, in the drawing system 5 as the fibre sliver for processing FGzb, and following the drawing system 5 as the delivered fibre sliver FGab.
The fibre sliver FGzu is conveyed from the feed stand 2 by sliver conveying equipment (not shown) to the feeding roller unit 3. This comprises three feeding rollers 3a, 3b, 3ab', which are a first, powered lower feeding roller 3a, a second, powered lower feeding roller 3b and an idle loading roller 3ab' moving as a result of its contact with the incoming fibre sliver FGzu.
Following the feeding roller 3, the fibre sliver FGzu is transported to the feeding sensor unit 4 by an feeding guide, not shown. This incorporates a pair of sensing rollers 4a, 4a', consisting of a sensing roller 4a on fixed bearings, and a movable sensing roller 4a'. Both the sensing roller 4a on fixed bearings and the sensing roller 4a' on movable bearings can be rotated about their vertical axis, but are shown rotated through 90° for the sake of representing them on the sketch. Both the sensing rollers 4a, 4a' are powered.
The feeding sensor unit 4 serves to obtain the measurements MLMi, ... , MLMn-2, MLMn-i, MLMn of the mass per unit length of sequential sections ABi, ..., ABn-2, ABn-i, ABn of the fibre sliver FGzu being supplied to the drawing system 5, i.e. the total mass of the fibre slivers FBI, FB2, FB3, FB4, FB5, FB6 being passed through it together. The reference ABn is given here to the segment that is being measured at the moment of the illustration as it passes through the sensor unit 4. Downstream of


the segment ABn we find segment ABn-i, followed then by segment ABn-2- The segment at the control action point REP is identified as ABi . For the sake of simplicity, the further segments are not given identifying references.
The individual measured segments ABi , ... , ABn-2, ABn-i/ ABn generally have a length of a few millimetres. For each measured segment ABi , ... , ABn-2, ABn-i, ABn the feeding sensor unit 4 generates a measurement MLMi , ... , MLMn-2, MLMn-i, MLMn. In order to take the measurements MLMi , ... , MLMn-2, MLMn-i, MLMn the sensor unit 4 has a pair of sensing rollers 4a, 4a'. Sensor units that operate in accordance with different physical principles are, however, are also possible. It is also conceivable that corrective procedures are applied to the determination of the measurement, in order for instance to eliminate disturbances.
The supplied fibre sliver FGzu is then transported from the feeding sensor unit 4 through a deflection unit (not shown) to the drawing system 5. This comprises a set of feeding rollers 5a, 5a', a set of central rollers 5b, 5b' and a set of delivery rollers 5c, 5c', 5c". The lower rollers 5a, 5b, 5c of the roller sets 5a, 5a'; 5b, 5b'; 5c, 5c', 5c"; are driven in such a way that the rotary speed increases from one set of rollers to another in the direction of movement LR. As a result of this, the fibre sliver for processing FGzb is drawn out in the preliminary drawing region 5d that is formed between the set of feeding rollers 5a, 5a' and the set of central rollers 5b, 5b', and also in the main drawing region 5e that is formed between the set of central rollers 5b, 5b' and the set of delivery rollers 5c, 5c', 5c". The draft in the preliminary drawing region 5d is referred to here as the preliminary draft VV, and the draft in the main drawing region is called the main draft HV. The preliminary draft W and the main draft HV together comprise the draft V of the drawing system 5.
The positions of the lower rollers 5a, 5b, 5c of the drawing system 5 are fixed. In contrast, the rotating upper rollers 5a', 5b' 5c' and the rotating diversion roller 5c" have bearings that can move transversely in respect of the direction of running LR, and are pressed against the lower rollers 5a, 5b, 5c by a loading mechanism, not


shown, in order to permit a firm grip on the fibre sliver FGzb. The upper rollers 5a', 5b' 5c' and the rotating diversion roller 5c" are therefore made to rotate by their contact with the fibre sliver FG as it passes by.
The outlet guide 6 comprises a funnel 8 and a powered delivery roller 9 on fixed bearings as well as a movable, powered delivery roller 9' that is loaded and thereby pressed against the fixed delivery roller 9. The funnel 8 is used to compress the fibre sliver FGab emerging from the drawing system 5 in order to create a single, compact fibre sliver FB. The delivery rollers 9 and 9' pull the fibre sliver FB out of the measuring funnel 8, and compact the fibre sliver FB that has been made even further.
The sliver depository 7 permits orderly storage of the fibre sliver FB that has been made by the drawing frame 1 in a sliver can K. It comprises a turntable 10 with a sliver duct 11 that is made to rotate about its axis, indicated by a dotted line. The sliver can K is placed on a can table 12 that is also made to rotate about its axis, indicated by a dotted line. Because there is an offset between the two axes, the fibre sliver FB can be placed in the sliver can K in orderly loops.
The drawing frame 1 includes a control unit 13 that operates a main motor 14 by specifying a set value SLG. The main motor 14, through an arrangement of gears shown schematically 14a, drives the lower roller 5c of the set of delivery rollers 5c, 5c', 5c" an, as a result of which the set value SLG for the primary motor 14 is, at the same time, a set value SLG for the delivery speed LG of the drawing system 5. In addition, the primary motor 14 drives the fixed-position delivery roller 9, the movable delivery roller 9', the turntable 10 and the can table 12 through the gear system 14a.
The primary motor 14 also, through a differential gear 15 and a further gear system 15a, drives the feed stand rollers 2a, 2b, the lower feeding rollers 3a, 3b, the fixed-position sensor roller 4a, the movable sensing roller 4a', the lower roller 5a of the set of feeding rollers 5a, 5a' and the lower roller 5b of the set of central rollers 5b, 5b'.


Whereas the rotary speeds of those working parts that are directly driven by the primary motor 14 have a fixed ratio when the drawing frame 1 is in its productive phase, and the rotary speeds of the working parts of the drawing frame 1 that are driven by the differential gear system 15 also have a fixed ratio, it is possible with the drive arrangement illustrated to adjust the rotary speed of the lower roller 5b of the set of central rollers 5b, 5b' in relation to the rotary speed of the lower roller 5c of the set of delivery rollers 5c, 5c', 5c" by means of a control adjustment. The total draft V can therefore be changed by adjusting the main draft HV. The preliminary draft VV, on the other hand, is constant.
It is also conceivable that the prehminary draft VV in the upstream preliminary draft region 5d could be controlled, or that no preliminary drawing region 5d is present at all. The only important point for the present invention is that the draft V as a whole can be controlled.
The change in the draft V, which serves to compensate for variations in the mass per unit length of the supplied fibre sliver FGzu, is created in the illustrated drawing frame 1 by a control adjustment generated by the control system 13 having an effect on the speed of rotation of the set of feeding rollers 5a, 5a' and the speed of rotation of the set of central rollers 5b, 5b'.
The control adjustment is therefore exercised on the feeding side of the drawing system 5; a control adjustment modifies the feeding speed EG of the drawing system 5.
Equally, a control adjustment could be carried out on the delivery side of the drawing system 5, in which case the delivery speed LG would be changed while the feeding speed EG always remained the same. This could, for instance, be useful if the drawing system 5 is supplied with its fibre sliver directly from a running carder, as in this case a lack of synchronicity between the carder's delivery speed and the


feeding speed EG of the drawing system 5 resulting from a control adjustment is avoided.
Further, it is also possible for control adjustments to be made both to the feeding side of the drawing system 5 and to the delivery side of the drawing system 5. It would be possible, for instance, for control adjustments designed to compensate for long-wave variations in the mass per unit length of the supplied fibre sliver FGzu to be carried out at the feeding side to the drawing system 5, and control adjustments to compensate for short-wave variations in the mass per unit length of the supplied fibre sliver FGzu to be carried out at the delivery side of the drawing system 5.
To compensate for variations in the mass per unit length of the supplied fibre sliver FGzu, the measurements MLMi , ... , MLMn-2, MLMn-i, MLMn taken by the feeding sensor unit 4 are transferred to the machine controller 13 and stored. On the basis of the particular measurement MLMi that corresponds to the segment ABi located at the control action point, a set value SEG is transferred to a servomotor 16 that acts on the differential gear 15 in such a way that the speed of rotation of the working parts situated upstream of the main drawing region HV is modified. If, for instance, the segment ABn has an above average mass per unit length, the draft V is increased in order to even out the fibre sliver FG.
A control system in which the point of measurement or sensor equipment 4 is located prior to the drawing system 5 is known as an open-loop controller. In a control system of this type it is necessary for the distance A covered by a segment AB of the fibre sliver FGzu between the sensor equipment 4 and the control action point REP, or the time taken for it to cover this distance, to be taken into account. The distance covered A and the time required for this are associated through the feeding speed EG of the supplied fibre sliver FGzu and the speed of the fibre sliver FGzb in the preliminary drawing region 5d.
The control action point REP is the place at which the control adjustment associated with a particular segment ABn of the fibre sliver FG is to take place. The position of the control action point REP is usually quoted as the distance A of the control action point REP from the sensor equipment 4. It is usually located in the upstream third of the main drawing region 5e.
A delay unit 18 is provided in order to ensure that at any particular time, the measurement MLMi of the mass per unit length that is used to carry out a control adjustment is the one that corresponds to the segment ABi of the fibre sliver FG that is located at the control action point REP. The delay unit 18 is here implemented as a FIFO memory 18. The length of the FIFO, i.e. the number of storage locations, is selected in such a way that the measurements MLMi -MLMn-i it contains represent the segments ABi - ABn-1 of the fibre sliver FG that are located between the feeding sensor 4 and the control action point REP. In the situation illustrated in Figure 1, the segment ABi is exactly at the control action point REP. The measurement MLMi is therefore read out of the FIFO memory 18 and supplied to the set value unit 17; this then determines a new set value SEG for the feeding speed EG of the drawing system 5 and sends it to the servomotor 16 so that the control adjustment can be carried out.
When the measurement MLMi is read from the FIFO memory 18, all the measurements MLM in the FIFO memory shift one place towards the output of the FIFO memory 18. At the same time, the measurement MLMn, representing the segment ABn of the fibre sliver FG, is read into the FIFO memory 18.
In order to control the shifting of the measurements MLM within the FIFO memory 18, a clock unit 19 is provided that supplies clock signals TS to the FIFO memory 18. The clock signal TS is generated from one or more measurements MEG of the feeding speed of the drawing system 5, which are also provided by the feeding sensor unit 4. As an alternative, the clock unit 19 can also be integrated directly into the feeding sensor 4.


The specified figure RP for the control action point REP can be set by a setting figure ERP supplied to the control unit 13. For this purpose the control unit 13 has a setting facility 20. This can, for instance, be a keyboard or a data interface, so that a setting figure ERP determined in a test run can be manually or automatically transferred as the specified figure RP for the control action point REP to the FIFO memory 18. The specified figure RP here determines the number of registers in the FIFO memory 18. If, for instance, the specified figure RP is now increased, the FIFO length is also increased, as a result of which the time during which a particular measurement MLM remains in the FIFO memory 18 is increased by one cycle of the clock 19. As a result, the control action point REP is shifted downstream, so that the distance A increases. If the specified figure RP is reduced, the control action point is shifted upstream in a similar way.
If, although not shown in Figure 1, control adjustments are made both at the input side of the drawing system 5 and on the delivery side of the drawing system 5, it is necessary for a control action point to be specified both for control adjustments at the input side as well as for control adjustments at the output side; the optimum values for the two control action points are not necessarily identical.
Optimum positioning of the control action point REP, in other words optimizing the distance A, is crucial for the quality of the fibre sliver FGab delivered from the drawing system 5. The optimum position of the control action point, however, cannot be determined with sufficient accuracy by analytical methods. For this reason, the setting figure ERP, and thereby the specified figure RP for the control action point REP, is determined in the prior art through adjustment or test runs prior to full operation, and is held constant for a relatively long period of time, for instance until a change of batch. If factors that affect the optimum positioning of the control action point REP change over that time, a drawing frame constructed according to the prior art will not take this into account.


In an example of an embodiment of a drawing frame 1 in accordance with the invention according to Figure 2, an adjusting facility 20 is also included to provide a setting figure ERP. This setting figure ERP, which can be determined in an automatic or manual test run, is supplied to a correction element 21. A correction figure ARP is also supplied to this correction element 21.
The correction element 21 is constructed in such a way that the specified figure RP is formed from the setting figure ERP and from the correction figure ARP; the specified figure RP is used in the manner now known to modify the length of the FIFO memory 18, and thereby to specify the control action point REP. Whereas the setting figure ERP is held constant for a relatively long period, i.e. for the period between the two test or adjustment runs, the correction figure ARP is adapted continuously, or semi-continuously, to the operating parameters of the drawing frame 1. This in turn results in a continuous, or semi-continuous modification of the specified figure RP and thereby of the control action point REP.
The correction figure ARP is determined by the evaluation unit 22 depending on a figure SLG that corresponds to the delivery speed of the drawing system 5 and also depending on a figure GM that corresponds to the feeding speed of the drawing system 5. The figure SLG that corresponds to the delivery speed LG of the drawing system 5 is the set value SLG for the delivery speed LG that is transmitted by the control unit 13 to the main motor 14.
The figure GM that corresponds to the feeding speed EG is a sliding mean value GM that is generated by the averaging unit 23 from set values SEG from the set value unit 17. The calculation of a mean figure is advantageous because the feeding speed EG changes with every control adjustment that is made. If the mean value is not calculated, the specified figure RP would also change every time a control adjustment is made, which could cause the textile machine's controller to become unstable. If, however, the sliding mean value GM is used, it is possible to adapt the control action point REP optimally to long-term changes in the feeding speed EG.


The evaluation unit 22 comprises a table 22, from which the correction figure ARP provided for the current combination of a sliding mean value GM and a set value SLG. Because the correction figure ARP does not have to be calculated while the drawing frame 1 is in operation it is possible, when the drawing frame 1 is operating, to determine a correction figure ARP quickly and with comparatively little expense.
The structure and the contents of the table 22 can be specified in advance on the basis of test runs. As an alternative, the evaluation unit 22 can be constructed in such a way that the correction figure ARP can be calculated during operation of the drawing frame in accordance with a previously defined function. The modification of the specified figure RP for the control action point REP is, in both cases, made on the basis of knowledge acquired in advance. It is therefore not necessary to examine the quality of the fibre sliver FGab emerging from the drawing system 5.
Figure 3 illustrates a further possible embodiment of a drawing frame 1 in accordance with the invention. Correction figures ARP are again here read from a table 22'. In order to take the delivery speed LG of the drawing system 5 into account, a delivery sensor unit 25 is provided that supplies measurements MLG of the delivery speed LG of the drawing system 5 to a standardization unit 26. This sense standardized figures MLG' for the delivery speed LG to the table 22'.
In order to take into account the feeding speed of the drawing system 5, measurements MLM of the mass per unit length of the fibre shver FGzu being supplied to the drawing system 5 are sent to another standardization unit 24. This supplies standardized measurements MLM' of the mass per unit length to the averaging unit 23; this uses them to calculate the sliding mean GM' and supplies it to the table 22'.


If we assume that the mean mass per unit length of the fibre sliver FGab emerging from the drawing frame, and the delivery speed LG of the drawing system 5 remain unchanged, the sliding mean GM' will provide a direct measure for the feeding speed EG of the drawing system 5.
The control action point is then modified as explained above on the basis of the correction figure ARP read from the table 22'.
The present invention is not restricted to the example embodiments illustrated and described. Modifications within the outline of the patent claims are possible at any time.


WE CLAIM:
1. A method for controlling the draft of a drawing system (5) in a textile
machine (1) preferably processing short staple fibres, particularly a spinning machine, for instance a ring spinning or rotary spinning machine, or a spinning preparation machine (1), for instance a carder or drawing frame (1), or a composite machine, comprising for example a carder and a drawing frame (1), in which
for sequential segments (ABi , ... , ABn-2, ABn-i, ABn) of a fibre sliver (FGzu) being supplied to the drawing system (5), a feeding sensor unit (4) upstream of the drawing system (5) takes a measurement (MLMi, ..., MLMn-2, MLMn-i, MLMn) of the mass per unit length in each case; and
in order to even out the mass per unit length of the incoming fibre sliver (FGzu) a control adjustment is made to the draft (V) of the drawing system (5) on the basis of one of the aforementioned measurements (MLMi ) as soon as the segment (ABi) associated with the aforementioned measurement (MLMi) reaches a control action point (REP) that is specified by a specified figure (RP); characterized in that
a modification of the specified figure (RP) for the control action point (REP) is carried out during the productive phase of the textile machine (1), wherein the specified figure (RP) is derived from a previously determined setting figure (ERP) and from a correction figure (ARP), and wherein the correction figure (ARP) is determined from a figure (MEG, GM, GM', SEG) corresponding to the feeding speed (EG) of the fibre sliver (FGzu) being supplied to the drawing system (5) and from a figure (MLG, SLG) corresponding to the delivery speed (LG) of the fibre sliver (FGab) emerging from the drawing system (5).
2. A method according to the foregoing claim characterized in that


the modification of the specified figure (RP) and/ or determination of the correction figure (ARP) are carried out automatically.
3. A method according to one of the foregoing claims
characterized in that
the modification of the specified figure (RP) is carried out on the basis of time,
length and/or of events.
4. A method according to one of the foregoing claims
characterized in that
the correction figure (ARP) is read from a previously determined table (22) on
the basis of a figure (MEG, GM, GM', SEG) corresponding to the feeding
speed (EG), and of a figure (MLG, SLG) corresponding to the delivery speed
(LG).
5. A method according to one of the foregoing claims
characterized in that
the setting figure (ERP) is determined in a test run making use of a parameter
indicative of quality, such as the CV% value for the fibre sliver (FGab)
emerging from the drawing system (5), or a magnitude derived from that.
6. A method according to one of the foregoing claims
characterized in that
the figure (MEG, GM, GM', SEG) that corresponds to the feeding speed (EG)
and/or the figure (MLG, SLG) corresponding to the delivery speed (LG) is
standardized before the correction figure (ARP) is determined.


7. A method according to one of the foregoing claims
characterized in that
a set value (SEG) for the feeding speed (EG) or a measurement (MEG) of the
feeding speed (EG) is used as the figure (MEG, GM, GM', SEG) that
corresponds to the feeding speed (EG).
8. A method according to one of the foregoing claims
characterized in that
a mean value (GM') is formed from a large number of set values (SEG) of the
feeding speed (EG) or from a large number of measurements (MEG) of the
feeding speed (EG), and is used as the figure (MEG, GM, GM', SEG) that
corresponds to the feeding speed (EG).
9. A method according to one of the foregoing claims
characterized in that
a set value (SLG) of the delivery speed (LG) or a measurement (MLG) of the
delivery speed (LG) is used as the figure (MLG, SLG) that corresponds to the
delivery speed (LG).
10. A method according to one of the foregoing claims
characterized in that
a mean value is formed from a large number of set values (SLG) of the
delivery speed (LG) or from a large number of measurements (MLG) of the
delivery speed (LG), and is used as the figure (MLG, SLG) that corresponds to
the delivery speed (LG).
11. A method according to one of the foregoing claims


characterized in that
an aforementioned control adjustment is made on the feeding side of the drawing system (5) and an aforementioned measurement (MLMi , ... , MLMn-2, MLMn-i, MLMn) of the mass per unit length, or a mean value (GM) of a large number of measurements (MLMi , ... , MLMn-2, MLMn-i, MLMn), as described, of the mass per unit length are used as the figure that corresponds to the feeding speed (EG).
12. A method according to one of the foregoing claims characterized in that
an aforementioned control adjustment is made on the delivery side of the drawing system (5) and an aforementioned measurement (MLMi, ..., MLMn-2, MLMn-i, MLMn) of the mass per unit length, or a mean value (GM) of a large number of measurements (MLMi , ... , MLMn-2, MLMn-i, MLMn), as described, of the mass per unit length are used as the figure that corresponds to the delivery speed (LG).
13. A textile machine (1), preferably a textile machine (1) that processes short
staple fibres, particularly a spinning machine, for instance a ring spinning or
rotary spinning machine, or a spinning preparation machine (1), for instance a
carder or drawing frame (1), or a composite machine, comprising for instance
a carder and a drawing frame (1), with
a drawing system (5), having a controllable draft (V) in order to even out the
mass per unit length of an incoming fibre sliver (FGzu);
a feeding sensor unit (4) for taking the measurements (MLMi, ... , MLMn-2,
MLMn-1, MLMn), each of which corresponds to the mass per unit length of a
segment (ABn-i, ABn, ABn+i) of the fibre sliver (FGzu) being supplied to the
drawing system (5); and


a control unit (13) for controlling the draft (V) of the drawing system (5) on the basis of one of the aforementioned measurements (MLMi) from the feeding sensor unit (4), where the control unit (13) is designed in such a way that a required control adjustment is made to the draft (V) of the drawing system (5) as soon as the segment (ABi) corresponding to the measurement (MLMi) reaches a control action point (REP) that is specified by a specified figure(RP); characterized in that
the control unit (13) is designed to modify the specified figure (RP) for the control action point (REP) during the productive phase of the textile machine (1), in which the specified figure (RP) can be formed on the basis of a previously determined setting figure (ERP) and of a correction figure (ARP), and wherein
the control unit (13) is designed for automatic determination of the correction figure (ARP) is determined from a figure (MEG, GM, GM, SEG) corresponding to the feeding speed (EG) of the fibre sliver (FGzu) being supplied to the drawing system (5) and from a figure (MLG, SLG) corresponding to the delivery speed (LG) of the fibre sliver (FGab) emerging from the drawing system (5).
14. A textile machine (1) according to one of the foregoing product claims, characterized in that
the control equipment (13) is designed for automatic modification of the specified figure (RP).
15. A textile machine (1) according to one of the foregoing product claims, characterized in that
the control equipment (13) is designed for automatic modification of the specified figure (RP) on the basis of time, length and/or events.


16. A textile machine (1) according to one of the foregoing product claims,
characterized in that
a previously specified formula is provided, from which the correction figure (ARP) can be calculated on the basis of a figure (MEG, GM, GM', SEG) corresponding to the feeding speed (EG), and of a figure (MLG, SLG) corresponding to the delivery speed (LG).
17. A textile machine (1) according to one of the foregoing product claims,
characterized in that
a previously specified table (22) is provided, from which the correction figure (ARP) can be read on the basis of a figure (MEG, GM, GM', SEG) corresponding to the feeding speed (EG), and of a figure (MLG, SLG) corresponding to the delivery speed (LG).
18. A textile machine (1) according to one of the foregoing product claims,
characterized in that
the control unit (13) is designed for automatically executing a test run, in which the setting figure (ERP) is determined making use of a parameter indicative of quality, such as the CV% value for the fibre sliver (FGab) emerging from the drawing system (5), or a magnitude derived from that.
19. A textile machine (1) according to one of the foregoing product claims,
characterized in that
a standardization stage (24) is incorporated for standardization of the figure (MEG, GM, GM', SEG) corresponding to the feeding speed (EG) and/or the figure (MLG, SLG) corresponding to the delivery speed (LG).


20. A textile machine (1) according to one of the foregoing product claims,
characterized in that
the figure (MEG, GM, GM', SEG) that corresponds to the feeding speed (EG) is a set value (SEG) for the feeding speed (EG) or a measurement (MEG) of the feeding speed (EG).
21. A textile machine (1) according to one of the foregoing product claims,
characterized in that
the figure (MEG, GM, GM', SEG) that corresponds to the feeding speed (EG) is a mean value (GM') formed from a large number of set values (SEG) for the feeding speed (EG) or from a large number of measurements (MEG) of the feeding speed (EG).
22. A textile machine (1) according to one of the foregoing product claims,
characterized in that
a set value (SLG) of the delivery speed (LG) or a measurement (MLG) of the delivery speed (LG) is the figure (MLG, SLG) that corresponds to the delivery speed (LG).
23. A textile machine (1) according to one of the foregoing product claims,
characterized in that
the value (MLG, SLG) that corresponds to the delivery speed (LG) is a mean figure formed from a large number of set values (SLG) of the delivery speed (LG) or from a large number of measurements (MLG) of the delivery speed (LG).
24. A textile machine (1) according to one of the foregoing product claims,


characterized in that
an aforementioned control adjustment can be made on the feeding side of the drawing system (5) and an aforementioned measurement (MLMi, ... , MLMn-2, MLMn-i, MLMn) of the mass per unit length, or a mean value (GM) of a large number of measurements (MLMi , ... , MLMn-2, MLMn-i, MLMn), as described, of the mass per unit length is the figure that corresponds to the feeding speed (EG).
25. A textile machine (1) according to one of the foregoing product claims, characterized in that
an aforementioned control adjustment can be made on the delivery side of the drawing system and an aforementioned measurement (MLMi , ... , MLMn-2, MLMn-i, MLMn) of the mass per unit length, or a mean value (GM) of a large number of measurements (MLMi, ..., MLMn-2, MLMn-i, MLMn), as described, of the mass per unit length is the figure that corresponds to the delivery speed (LG).

ABSTRACT
A method is proposed for controlling the draft in the drawing system (5) in a textile machine (1) in which for sequential segments (ABi , ... , ABn-2, ABn-1, ABn) of a fibre sliver (FGzu) being supplied to the drawing system (5), an feeding sensor unit (4) upstream of the drawing system (5) takes a measurement (MLMi , ... , MLMn-2, MLMn-i, MLMn) of the mass per unit length in each case; and in order to even out the mass per unit length of the incoming fibre sliver (FGzu) a control adjustment is made to the draft (V) of the drawing system (5) on the basis of one of the aforementioned measurements (MLMi ) as soon as the segment (ABi ) associated with the aforementioned measurement (MLMi) reaches a control action point (REP) that is specified by a specified figure (RP); a modification of the specified figure (RP) for the control action point (REP) is carried out during the productive phase of the textile machine (1), where the specified figure (RP) is derived from a previously determined setting figure (ERP) and from a correction figure (ARP), and where the correction figure (ARP) is determined from a figure (MEG, GM, GM, SEG) corresponding to the feeding speed (EG) of the fibre sliver (FGzu) being supplied to the drawing system (5) and from a figure (MLG, SLG) corresponding to the delivery speed (LG) of the fibre sliver (FGab) emerging from the drawing frame. A textile machine is also proposed.
To
The Controller of Patent
The Patent Office
Mumbai





Documents:

1021-MUM-2007-ABSTRACT(GRANTED)-(8-12-2011).pdf

1021-mum-2007-abstract.doc

1021-mum-2007-abstract.pdf

1021-MUM-2007-CANCELLED PAGES(14-9-2011).pdf

1021-MUM-2007-CLAIMS(AMENDED)-(14-9-2011).pdf

1021-MUM-2007-CLAIMS(AMENDED)-(4-11-2010).pdf

1021-MUM-2007-CLAIMS(CANCELLED PAGES)-(4-11-2010).pdf

1021-MUM-2007-CLAIMS(GRANTED)-(8-12-2011).pdf

1021-MUM-2007-CLAIMS(MARKED COPY)-(14-9-2011).pdf

1021-mum-2007-claims.doc

1021-mum-2007-claims.pdf

1021-mum-2007-correspondace-received.pdf

1021-MUM-2007-CORRESPONDENCE(28-5-2012).pdf

1021-MUM-2007-CORRESPONDENCE(29-6-2011).pdf

1021-MUM-2007-CORRESPONDENCE(29-7-2011).pdf

1021-mum-2007-correspondence(3-7-2007).pdf

1021-MUM-2007-CORRESPONDENCE(4-11-2010).pdf

1021-MUM-2007-CORRESPONDENCE(5-3-2012).pdf

1021-mum-2007-correspondence(ipo)-(27-11-2009).pdf

1021-MUM-2007-CORRESPONDENCE(IPO)-(9-12-2011).pdf

1021-mum-2007-description (complete).pdf

1021-MUM-2007-DESCRIPTION(GRANTED)-(8-12-2011).pdf

1021-MUM-2007-DRAWING(GRANTED)-(8-12-2011).pdf

1021-mum-2007-drawings.pdf

1021-MUM-2007-ENGLISH TRANSLATION(4-11-2010).pdf

1021-mum-2007-form 1(3-7-2007).pdf

1021-MUM-2007-FORM 1(5-3-2012).pdf

1021-MUM-2007-FORM 13(5-3-2012).pdf

1021-MUM-2007-FORM 2(GRANTED)-(8-12-2011).pdf

1021-MUM-2007-FORM 2(TITLE PAGE)-(30-5-2007).pdf

1021-MUM-2007-FORM 2(TITLE PAGE)-(5-3-2012).pdf

1021-MUM-2007-FORM 2(TITLE PAGE)-(GRANTED)-(8-12-2011).pdf

1021-MUM-2007-FORM 26(14-9-2011).pdf

1021-MUM-2007-FORM 26(29-7-2011).pdf

1021-MUM-2007-FORM 26(5-3-2012).pdf

1021-MUM-2007-FORM 3(30-5-2007).pdf

1021-MUM-2007-FORM 3(4-11-2010).pdf

1021-MUM-2007-FORM 3(5-3-2012).pdf

1021-MUM-2007-FORM 5(5-3-2012).pdf

1021-mum-2007-form-1.pdf

1021-mum-2007-form-18.pdf

1021-mum-2007-form-2-1.doc

1021-mum-2007-form-2.doc

1021-mum-2007-form-2.pdf

1021-mum-2007-form-26.pdf

1021-mum-2007-form-3.pdf

1021-mum-2007-form-5.pdf

1021-MUM-2007-OTHER DOCUMENT(14-9-2011).pdf

1021-MUM-2007-OTHER DOCUMENT(5-3-2012).pdf

1021-MUM-2007-PETITION UNDER RULE 137(4-11-2010).pdf

1021-MUM-2007-REPLY TO EXAMINATION REPORT(14-9-2011).pdf

1021-MUM-2007-REPLY TO EXAMINATION REPORT(4-11-2010).pdf

1021-MUM-2007-REPLY TO HEARING(30-8-2011).pdf


Patent Number 250123
Indian Patent Application Number 1021/MUM/2007
PG Journal Number 49/2011
Publication Date 09-Dec-2011
Grant Date 08-Dec-2011
Date of Filing 30-May-2007
Name of Patentee RIETER INGOLSTADT SPINNEREIMASCHINENBAU AG
Applicant Address FRIEDRICH-EBERT-STRASSE 84, D-85055 INGOLSTADT.
Inventors:
# Inventor's Name Inventor's Address
1 JOACHIM DAEMMIG AM MUEHLANGER 50, 85053 INGOLSTADT.
PCT International Classification Number D01H5/38
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA