EP2738124B1 - Method for controlling the acceleration of a coil drive roller - Google Patents

Description

The invention relates to a method for controlling the acceleration of a bobbin drive roller at a workstation of a cheese-producing textile machine, in which the bobbin drive roller drives a package spool frictionally and wherein the spooling progress is monitored during the spool travel.

Cheese-making textile machines have long been known; They usually consist of a large number of similar workstations arranged next to each other in series. On the jobs, for example, an automatic winder spinning cops that have relatively little thread material, rewound to large-volume cheeses, which are needed in downstream in the production process textile machines, such as looms. However, such winding units are also present in other textile machines, for example in rotor spinning machines, friction spinning machines or air spinning machines in connection with spinning stations, in order to allow the winding of cheeses. Thread supplier is then instead of a spinning cop or a supply spool the appropriate spinning station.

The cheese, referred to in this context as a package, a job is driven at the periphery by a coil drive roller. The bobbin drive roller may be formed, for example, as a yarn guide drum and leads the yarn during the winding process before emergence on the cross-wound bobbin back and forth. Alternatively, the thread is changed by means of a separate thread guide in front of the cross-wound bobbin, wherein the bobbin drive roller is then not provided with Fadenführungsnuten.

During the winding process on an automatic winder, the yarn quality of the supply bobbin is improved by cleaning out yarn defects, for example from thick and thin areas. The current thread is monitored by a so-called thread cleaner, which initiates a cleaning step and a cleaning of the thread error when discovering a thread error.

If the thread breaks during the bobbin travel, either because the delivery is interrupted, or because the thread is not able to withstand the winding tension, or because the cleaner separates the thread, this event must be detected to cause operations which are necessary to remedy the thread breakage. For this purpose, the winding unit in question is stopped, that is, the package is lifted from the spool drive roller and both the package and the bobbin drive roller are braked to a standstill. The yarn is restored by a yarn end joining operation, and the package reel drive roller must be accelerated from the stand to the winding speed. This so-called run-up is divided into two phases. The first phase of the run-up is referred to as a soft start and includes the acceleration of the bobbin drive roller, for example, up to the yarn speed of 100 m * min ^-1 . The further acceleration, until reaching the winding speed, is called run-up and is the subject of the present invention.

Such a method for controlling the winding speed or the acceleration to the winding speed is the DE 42 30 984 C2 removable. In this patent application it is disclosed that several start-up acceleration commands with different characteristics of the startup speeds whose slopes are below a limit value are stored in a central control unit. Before start of winding, the start-up acceleration command is selected with the steepest increase in speed, in which disadvantages such as too high slip or yarn breaks are still avoided.

A disadvantage of this known method is that one must be selected by the operator from predetermined characteristics and this characteristic specifies an acceleration that was not determined individually for the respective package. However, such predetermined characteristics can only cover areas to which the packages are then assigned and are therefore not always optimal. In addition, manual entry also always entails the risk that errors will be made and a wrong characteristic curve selected.

Another disadvantage is that a continuous run-up, as described in this document, would result in even slippage, which in turn causes winding patterns. In this case, the threads lie on the package partially over each other and on the coil jacket beads arise, which can also be seen on the coil edges. In the further processing it comes through the close together lying yarn layers to entanglements or it will be taken during subsequent stripping several layers and it comes to yarn breakage.

Based on the aforementioned prior art, the invention has the object to further optimize the winding process, in particular to improve the acceleration of the package to the winding speed.

This object is achieved by the characterizing features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

According to claim 1 it is provided that the bobbin drive roller is sequentially accelerated to predetermined acceleration levels, the angular velocities of both the bobbin drive roller and the package are detected and compared with each other and depending on the result of this comparison, the acceleration to the next acceleration stage is started and that the start the acceleration stages of the bobbin drive roller is controlled during startup in response to the respective winding progress of the package.

This type of acceleration of the bobbin drive roller with constantly changing slip is ideal for avoiding winding patterns even during run-up. The comparison of the angular speeds of the package and the bobbin drive roller, which correlate with the peripheral speeds, is the basis for the initiation of the next acceleration stage and ensures that only the next acceleration stage is initiated when either the package falls below an acceleration value or a speed difference to the bobbin drive roller.

In accordance with the winding progress of the package, its diameter, its mass or its wound thread length continuously increases, wherein each of these sizes can be used as a measure of the winding progress. Since the moment of inertia also increases with increasing winding progress, the respective start of the acceleration stages takes place as a function of the winding progress, on the one hand to the slip between package and bobbin drive roller during the entire bobbin travel on the other hand, however, to take the highest possible value and thus to be able to ensure optimized productivity. Especially at the beginning of the coil travel very high acceleration values are achieved, which significantly reduce the acceleration times. This is particularly significant in automatic wiping machines, as often occur due to Kopswechseln and cleaning cuts ramps.

Preferably, as described in claim 2, the start of the next acceleration stage of the bobbin drive roller during a run-up in each case falls below a limit for the circumferential acceleration, ie the product of angular acceleration and diameter of the package. This limit value is reduced with increasing winding progress of the package. By acceleration stage in the sense of this invention is to be understood that the bobbin drive roller is accelerated as much as possible in a first phase, optionally up to a predetermined speed and then remains at this speed level until the acceleration phase of the next acceleration stage is initiated. Since the moment of inertia of the package increases with increasing Spulfortschritt, the acceleration during startup to avoid too high slip towards the end of the coil travel must be slower than it is possible at the beginning.

As set forth in claims 3 and 4, in an embodiment of the invention, the respective winding progress of the package associated limits for the circumferential acceleration of the package either based on the winding progress dependent inertial moments of the package determined or empirically determined at one or more jobs and then for the other jobs. The limit values which initiate the next acceleration stage of the bobbin drive roller can thus be determined by calculation or determined by means of tests during a bobbin travel.

wobei m die Masse und r den Radius der Hülse beziehungsweise Spule darstellt.The moment of inertia I of a cylindrical coil is calculated as follows:
$I=\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="imgf0001.png"\; state="\{\{state\}\}">m</figure-callout>}}{2}*\left({{\mathrm{<figure-callout\; id="2"\; label="r\; shell"\; filenames="imgf0001.png"\; state="\{\{state\}\}">r\; </figure-callout>}}_{\mathrm{shell}}}^{\mathrm{2}}+{{\mathrm{<figure-callout\; id="2"\; label="r\; Kitchen\; sink"\; filenames="imgf0001.png"\; state="\{\{state\}\}">r\; </figure-callout>}}_{\mathrm{Kitchen\; sink}}}^{\mathrm{2}}\right)$

where m represents the mass and r the radius of the sleeve or coil.

The volume V of a hollow cylinder is calculated as follows:
V = π _* h _* (r _coil ² - r _sleeve ² ) where h indicates the height.

The mass m of the coil is calculated:
m = ρ * V where ρ represents the density.

The following formula results for the moment of inertia I: $$I=\frac{\rho *\pi *\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="imgf0001.png"\; state="\{\{state\}\}">H</figure-callout>}}{2}*\left({{\mathrm{r}}_{\mathrm{Spulse}}}^{\mathrm{4}}-{{\mathrm{<figure-callout\; id="4"\; label="r\; shell"\; filenames="imgf0001.png"\; state="\{\{state\}\}">r\; </figure-callout>}}_{\mathrm{shell}}}^{\mathrm{4}}\right)$$

Claim 5 describes that within an acceleration stage in the last third of the run-up, the time is measured until a value representing the synchronization of the peripheral speeds of the package and the bobbin drive roller is reached or an adjustable value below, and that at a predetermined deviation from a target period of Start of the acceleration stages for the following startup operations is changed so that it corresponds to a different winding progress of the package. The so-called ramp-up time value determined in this way is an indicator of how much slippage set in at the end of the run-up and allows conclusions to be drawn about the acceleration that is possible without sacrificing quality. The comparison of the time duration until a value representing the synchronization of the circumferential speeds of the package and the bobbin drive roller is reached, with a set value can be used to correct the calculated or empirically determined limits for the circumferential acceleration of the package for the start of the acceleration stages in Be used within the framework of a control loop. In this case, an intervention takes place only if deviations from the standard determined, in particular by means of coil-specific events (for example, failure or fluctuation of the paraffin application).

Advantageously, according to claim 6, the time required to reach a value representing the tracking of the peripheral speeds of the bobbin drive roller or a more adjustable value below is determined in the last acceleration stage in which the bobbin drive roller reaches the final winding speed, since at the end the run-up the safest Value can be determined and is expected at the necessary correction of the least loss of production. In this acceleration stage, there is no intervention in the run-up, for example, by unnecessary extension of an intermediate stage for the acceleration time determination, since this is extended anyway to the final production speed. Furthermore, aborted ramp-ups that would falsify the result are not recorded thereby and thus are not included in the regulation of the acceleration.

In accordance with claim 7, when the setpoint time span is exceeded, the acceleration stages are delayed by a predefinable value, so that the slip is reduced. The control of the starting points for the acceleration stages then corresponds to a higher winding progress. Similarly, claim 8 discloses that, however, when the setpoint time span is undershot, the acceleration stages are started by a predefinable value, so that the ramp-up time is shortened and thus corresponds to a lower spooling progress.

In an advantageous embodiment, as set forth in claim 9, the target time period is repeatedly measured before an adjustment taking into account the current winding conditions. This procedure ensures that it is not frequently switched back and forth between different settings due to so-called outliers. So only certain deviations are taken into account.

The present invention will be explained below with reference to a schematically illustrated workstation of an automatic winder.

Figur 1:

schematisch dargestellte Arbeitsstelle eines Spulautomaten

Figur 2:

Diagramm des Verlaufs des Hochlauf-Wertes in Abhängigkeit vom Auflaufspulendurchmesser.

Show it

FIG. 1:

schematically illustrated workstation of an automatic winder

FIG. 2:

Diagram of the course of the ramp-up value as a function of the package diameter.

FIG. 1 shows that at each workstation from a feed bobbin 1, in particular a spinning cop generated on a ring spinning machine, a yarn 2 is withdrawn, which is wound onto a cheese 3, for example a conical cheese.

The cross-wound bobbin 3, which is held by means of a pivotable creel, not shown, rests on a bobbin drive roller 4, in particular on a so-called yarn guide drum, by means of which the cheese 3 rotates and the yarn 2 in the axial direction of the cross-wound bobbin 3 is supplied. Conceivable in the context of the present invention but would also be another type of Fadenchangiereinrichtung, for example, a so-called Fingerfadenführer.

On the way from the supply reel 1 to the cheese 3, the yarn 2, which is usually a yarn formed on a ring spinning machine, passes through a yarn guide 5, a controlled yarn tensioner 6, a yarn tension sensor 9 and a sensor in the form of a cleaner 8. Der Thread tensioner 6 acts on the running thread 2 with a predeterminable clamping force. The cleaner 8 monitors the running thread 2 for errors, especially on thick or thin areas.

In the yarn path after the yarn tension sensor 9, a paraffin worker 14 and optionally another yarn guide 10 are arranged. By means of the paraffin wax 14, paraffin particles are applied to the yarn, which improve the running and sliding properties of the yarn, which is of considerable importance in particular in subsequent processing processes, for example in knitting and knitting.

The thread tensioner 6, the thread tension sensor 9, the cleaner 8 and a splicer 7 for connecting the thread ends before the next run-up are connected to a control and regulation unit 11, a so-called workstation computer.

The bobbin drive roller 4 of each work station is driven by its own drive motor 12, which is equipped with a speed control, in particular a Trommelmotorendstufe 13. The control of the Trommelmotorendstufe 13 is carried out by the workstation computer 11 depending on job-specific parameters such as the thread tension. An unillustrated central computer of the automatic winder is connected, for example via a bus line with the workstation computers 11 of the numerous jobs.

If unacceptable yarn defects occur, the running yarn 2 is interrupted by a cleansing cut and the defective yarn piece is cut out. For this purpose, the package 3 is lifted from the bobbin drive roller 4 and both package 3 as well as the bobbin drive roller 4 are braked to a standstill. The now existing two thread ends are connected to each other by means of a known splicer 7. Thereafter, the package 3 is lowered back to the bobbin drive roller 4 and the bobbin drive roller 4 is accelerated. Up to a yarn speed of, for example, 100 m * min ^-1 , the so-called soft start takes place, after which the startup according to the invention follows. Within an acceleration stage, the bobbin drive roller 4 is accelerated to a predetermined level and remains there. Meanwhile, the peripheral speed or the circumferential acceleration, that is, the slope of the peripheral speed curve, of the package 3 is detected. If, for example, the circumferential acceleration of the package 3 falls below the limit value adapted to the diameter of the package 3, the next acceleration stage starts. Once the bobbin drive roller 4 has reached the final winding speed, is no longer accelerated and it is detected, the time required for the package 3 to also reach their final winding speed. This ramp-up time is compared with a so-called ramp-up time limit. If, for example, the ramp-up time limit value is 900 ms and the run-up time of the package 3 took 1000 ms, the acceleration for the subsequent run-ups is reduced, that is, the acceleration stages are delayed. The acceleration time value is recorded after every completed startup.

So that the limit values of the acceleration stages are not changed after each individual run-up and, as the case may be, switched back and forth between different settings of the acceleration stages, the determined run-up times of several run-ups are summarized. Thus, the limits of the acceleration levels can be reliably selected without individual outliers adversely affect the limits.

FIG. 2 illustrates the change in the limits of acceleration of the package 3, which initiate the next acceleration stage of the bobbin drive roller 4, depending on the package diameter. The acceleration limits of the package 3 are shown on the ordinate. The abscissa scales the package diameter starting with the diameter of the empty shell. At the beginning of the coil travel there is a phase in which even at a relatively high acceleration the package 3, the next acceleration stage of the bobbin drive roller 4 is initiated. Since the inertia of the package 3 is relatively low over a certain period of time, the high initial limit can be maintained here, up to about 110 mm in diameter. With increasing diameter of the package 3, the acceleration value decreases. At the end of the coil travel, a phase of constant limit values can be set within the scope of the present invention if the acceleration limit values have reached a lower level. This makes it clear that the invention does not require that a (uniform) lowering of the acceleration limit value must take place during the entire coil travel.

The limit values for the circumferential acceleration of the package 3 are not only dependent on the inertia, but are influenced by property-related parameters, such as, for example, the paraffinization. The curves of the course of the run-up value for the respective batch are stored in the workstations or central computer, so that they can be used as a basis again in the next same batch.

Claims (9)

1. Method for controlling the acceleration of a bobbin drive roller (4) at a workstation of a textile machine producing cross-wound bobbins, wherein the bobbin drive roller (4) drives a take-up bobbin (3) by friction, and whereby winding progress is monitored during bobbin travel,
   characterised in that
   the bobbin drive roller (4) is accelerated to pre-determinable acceleration steps one after the other, whereby the angle speeds of the bobbin drive roller (4) as well as of the take-up bobbin (3) are recorded and compared with each other and acceleration to the next acceleration step is started depending on the result of this comparison, and the start of the acceleration steps of the bobbin drive roller (4) is controlled during a ramp-up depending on the relevant winding progress of the take-up bobbin (3).
2. Method according to claim 1, characterised in that the start of the next acceleration step of the bobbin drive roller (4) during a ramp-up is realised at each fall below a limit value for the circumferential acceleration of the take-up bobbin (3), and in that this limit value is reduced with increasing winding progress of the take-up bobbin (3).
3. Method according to claim 2, characterised in that the limit values for the circumferential acceleration of the take-up bobbin (3) associated with the relevant winding progress of the take-up bobbin (3) are determined on the basis of the inertia moments of the take-up bobbin (3).
4. Method according to claim 2, characterised in that the limit values for the circumferential acceleration of the take-up bobbin (3) associated with the relevant winding progress of the take-up bobbin (3) are empirically determined at one or more workstations and then used as a basis for the remaining workstations.
5. Method according to one of the claims 1 to 4, characterised in that in the last third of the ramp-up, the time within an acceleration step until one of the take-up bobbin (3) and the bobbin drive roller (4) reach a value that represents synchronisation with the circumferential speeds or a settable value below the same is measured, and in that the start of the acceleration steps is changed for the following ramp-up processes from a target time period with a pre-determinable deviation in such a way that it equals a different winding progress of the take-up bobbin (3).
6. Method according to claim 5, characterised in that the time for reaching a value representative for synchronisation with the circumferential speeds of the bobbin drive roller (4) with the take-up bobbin (3), or a settable value below the same, is determined during the acceleration step during which the bobbin drive roller (4) reaches winding speed.
7. Method according to claim 5, characterised in that the start of the acceleration steps is delayed by a pre-determinable value when the target time period is exceeded.
8. Method according to claim 5, characterised in that the start of the acceleration steps is brought forward by a pre-determinable value when the target time period is not reached.
9. Method according to claim 7 or 8, characterised in that the time is measured repeatedly and the acceleration steps adjusted, bearing in mind several measurement values.

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