EP2462268B1 - Method and device for monitoring the thread arrival during the weft insertion of different weft threads on a weaving machine - Google Patents

Description

The present invention relates to a method and apparatus for monitoring the weft arrival of weft yarns on a loom during weaving pattern dependent entry of various weft yarns into a shed.

In weaving machines monitoring of weft threads during the weft insertion are known in the prior art.

Such a device shows, for example, the EP 0 374 398 B1 , This relates to a weft thread monitor for air-jet weaving machines with a weft insertion of threads of different quality, wherein the threads are subtracted from the respective thread store and entered via an air entry control controlled main and relay nozzles in the air duct of a Profilriets and thus in a shed. On the output side of the Profilriets the weft detector is arranged with sensors whose electrical signals are fed to the input of an amplifier and then the air intake control and evaluated there. Depending on the result of the evaluation, the entry process is continued or interrupted and an error message is output. During each weft insertion or monitoring operation, an electrical signal is supplied to the amplifier of the weft detector by the air entry control, which is determined by the mechanical and air-effective properties of the respective weft thread. The amplifier is designed such that, depending on the characteristics of the weft threads, it amplifies the electrical output signal of the sensor before it is fed to the air intake control for evaluation. At the Lufteintragssteuerung programming is provided, with which the mechanical and air-effective properties of the weft threads for the weave or the shot sequence detected, processed, stored and supplied in the form of electrical correction signals webmusterabhängig the amplifier.

This correction of the output signals that the sensor sends to the air intake control via the amplifier is useful in order to avoid weaving errors. In this way, the system sensor / amplifier can be informed in a forward-looking manner, which signal strength at the next weft insertion is to be expected depending on the properties of the weft thread and how the signal amplification is to be made so that the evaluation unit of the air entry control detects whether the weft thread arrived at the exit side - ie correctly registered or not.

By such adaptation to the respective weft yarn weaving errors can be avoided, for example, by the fact that fiber fly a sensor signal (= thread present) triggers, although the weft itself is not properly registered, that is, arrived at the firing monitor or sensor. However, the web pattern-dependent weft properties must first be communicated to the system by the operator. The programming unit of the Lufteintragssteuerung determined from the appropriate correction signals for the amplifier. The manner in which a separate detection of the different types of weft threads by the system sensor / amplifier air entry control of the loom is to take place is not disclosed.

The EP 1 445 365 B1 describes a method for monitoring weft threads on a weaving machine during weaving pattern-dependent insertion of various weft threads into a shed, wherein each weft thread to be inserted is monitored at the end of the weft insertion path by one or two sensors, which detects at certain times whether a weft thread is present or not. In this case, outside the period in which the passage of a weft thread is monitored by the sensor, a reference threshold value and a gain factor are calculated from the sensor signal by means of an electronic control unit. This calculation takes place at certain times, which are specified via inputs of the operator with regard to the properties of the weft thread to be respectively entered in accordance with the weaving pattern. When comparing the signal actually generated when the weft thread passes through the sensor with the reference threshold, the presence of various additional conditions is checked. These additional conditions are also predetermined by the operator, depending on the type of each weft to be entered weft.

The object of the present invention is to provide a method and a device with which different properties, which are decisive for monitoring the yarn arrival of the weft thread, are detected independently by the system "sensor / control unit weaving machine" during the weft insertion on a weaving machine. This is to be an optimal adaptation of the monitoring process to different types of weft threads and thus avoiding weaving or Fehlangestellungen on the weaving machine can be made possible without the operator to make inputs regarding the properties of the weft threads in the control unit of the loom.

The object is achieved by a method and a device according to the independent claims.

A method for monitoring the yarn arrival of weft threads on a loom during the web pattern-dependent entry of different weft threads in a shed provides the monitoring of a weft to be inserted in the region of the end of the weft insertion path by at least one opto-electronic sensor.

Depending on various properties of the weft thread which are decisive for the monitoring of the weft thread, different electrical signal characteristics are generated by the sensor as a result of the passage of weft threads with various such properties.

These waveforms are evaluated by at least one electronic control unit.

According to the invention, a reference signal which is typical for each weaving pattern-dependent weft yarn is calculated and stored by means of the control unit for each weft thread to be weft-fed by several weft insertion points on the weaving machine as the respective weft thread passes through the sensor.

For this purpose, the fact is used that sensor elements, which are usually used to monitor weft threads on weaving machines, when passing through e.g. of a thin weft thread to provide a different output signal than when passing through a thick weft thread. In weaving pattern-dependent weft insertion of weft threads, e.g. different thickness results therefore for each weft insertion in the weave a characteristic waveform at the output of the sensor. For different types of weft threads, however, other properties of the weft threads may also be the cause of different signal patterns when a weft thread passes through the sensor. A smooth weft without fibers will produce different waveforms than a hairy weft - even if they have the same thread size.

For monitoring the weft thread, sensors with different technologies can be used within the scope of the invention, as far as they generate signal traces as the weft thread passes through the sensor, which are different for different types and different behavior of weft threads.

These may be, for example, opto-electrical sensors in which one or more light beams are emitted by at least one transmitter and the light is detected by one or more receivers, as long as the light beam is not or only partially e.g. interrupted by a weft thread. Such sensors are often housed today with its own electronics unit within a common housing. This electronic unit controls e.g. the light signal and prepares the signals generated by the light receiver for further processing in the electronic control unit of the loom. It may also be necessary to send signals to the electronics unit of the sensor from the loom control unit. In the context of the invention, "sensor" means an assembly which, depending on the type of sensor, can also comprise an electronic unit of the type described here. By "waveform" of the sensor is thus meant the course of the signal, which is generated either by the sensor directly or by the associated with this own electronic unit.

However, it is also possible to use sensors in which the light emitted by at least one transmitter reflects off obstacles in the region of the light beam and detected by one or more receivers arranged to receive reflected light from the receivers and convert the light intensity and / or the position into an electrical signal.

Depending on the type of sensor, different positions of the weft thread passing through the sensor in the region of the sensor can also generate different signal profiles that can be evaluated by the control unit. This means that these sensors also take into account the behavior of the weft during the determination of the signal characteristics.

The sensor is usually mounted at the end of the weft insertion path. Often it makes sense to arrange one or more further sensors - with respect to the weft insertion direction - farther back, away from the first sensor. Thus, e.g. be determined in an air-jet weaving machine, whether a weft thread portion, which has been recognized correctly by the first sensor, not previously torn already during the weft insertion. The arrival of a weft thread or weft thread section in such a second sensor can also be monitored by the method according to the invention.

The sensors referred to here are thus in any case positioned in the region of the weft insertion path.

The analog electrical signal waveforms of the sensors, of which the invention is mentioned, are characterized by different signal levels and different times at which the signals are generated by the sensor.

With electronic control unit here is meant the totality of all hardware and software elements that receive electrical signals within the loom, process and forward to weaving machine components or display units. Depending on the embodiment of the sensor of this, if necessary, to distinguish the above-described own electronic unit of the sensor, but which may also be integrated into the control unit.

According to the invention, for a weaving cycle, the actual signal course which is generated by the sensor when a weft thread passes through is electronically compared by means of the control unit with the stored reference signal of the weft thread to be introduced in this weaving cycle as a function of the weaving pattern.

In general, the reference signal consists of a single signal value (e.g., an average value) that is electronically compared at a particular time during the weaving cycle with the actual waveform by the control unit.

As described above, according to the invention, to calculate the reference signal for a weft thread to be entered in a weaving pattern, at least one reference signal typical of the weft yarn to be introduced in dependence on the weaving pattern is calculated and stored from a plurality of signal curves generated by weft insertion on the weaving machine as the respective weft thread passes through the sensor.

For this calculation, but also for the comparison in the current weaving cycle, the actual signal curve can still be processed, that is to say electronically amplified, integrated, averaged or otherwise suitably changed for the evaluation and the electronic comparison in a manner known per se. However, it is also conceivable, instead of a single signal value, to store a reference signal in the form of a signal curve and to compare it with an actual analogue signal characteristic prepared for the evaluation and the comparison at specific times. Such methods for comparing different waveforms are known in the art. According to the invention, the signal curves are taken into account, which are generated by the sensor during the passage of the weft thread.

When using the method with respect to the signals of a further sensor which is intended to detect, for example, a torn-off thread end, the determination of the reference signals can in principle also take place from the signal progressions of the first sensor. However, it is also possible to use those gradients that the second sensor generates in the event of a fault - weft thread being torn off during entry. The evaluation of the signals in the electronic control unit for the purpose of monitoring the yarn arrival of the weft thread can take into account not only the comparison of the signal characteristics of the sensor but also further electrical signal values present in the control. However, signal values due to operator input regarding the various weft threads to be monitored are not required.

In a preferred embodiment, depending on the result of the evaluation, the electronic control unit outputs at least one of a plurality of possible signals. Preferably, at least one signal for WM stop is output if the evaluation of the signals by the controller shows that the weft thread has not arrived or broken in the area of the end of the shed. The web process is interrupted; It makes sense to output an error message to the operator. This output is e.g. to various components involved in the web process. These may be, for example, the main drive, the feeder or the weft insertion components. A signal output to the possibly existing electronic unit of the sensor is feasible if necessary.

In a further embodiment of the invention, the evaluation in a learning phase of the loom is used to calculate first reference signals without error messages are already brought about with stop the loom when the comparison between the actual signal and the reference signal is negative. The control unit operates in a so-called lemphase. This is e.g. useful when weaving new Gewebemustem with changed web pattern depending weft threads to be entered.

It is also conceivable, of course, to download reference signals already determined in earlier production runs for each weft thread to be entered with the entire tissue and pattern data of a specific tissue from an external data carrier. Then the learning phase can be omitted.

In a further embodiment of the invention, the calculation of the reference signal during regular weaving operation is regularly repeated by means of the control unit and thus adapted to the current properties of the respective weft thread to be weft-bound.

A device according to the present invention comprises at least one sensor in the region of the entry path for monitoring the thread arrival when various weft threads are introduced into the shed of a weaving machine.

The sensor is of the type required for the method according to the invention as described above. That is, sensors are used which generate signals as the weft passes through the sensor which are different for different types and / or different behavior of weft threads. These are predominantly opto-electrical sensor principles that generate waveforms either by interrupting light beams or by their reflection at obstacles.

These are sensors or even sensor-electronic assemblies-so-called firing monitors-with which analog electrical signal waveforms are generated, which are characterized by different signal levels at different times.

The sensor or sensors are usually mounted at the end of the entry path.

Furthermore, a control device is provided, which is connected signal transmitting with one or more sensors. The control device comprises elements that enable the entry of different weft threads depending on the weave pattern.

The control device is signal-transmitting connected to other important for the weaving process components of a loom; for example with the main drive and the components of the weft insertion.

Furthermore, display devices can be provided which make messages of the control device visible to the operator.

According to the invention, the control unit is equipped with such hardware and software that the method according to the invention described above can be carried out with it. For this purpose, electronic modules or software modules are provided, which allow a storage of signal waveforms, averaging and the comparison of individual signals or entire signal waveforms. The extent to which hardware and / or software is used here remains up to the person skilled in the art to whom such components or software modules are known in principle.

In this case, an embodiment is preferred in which various signals can be output in the control unit as a function of the evaluation of the signal profiles of the sensors. In particular, the output of a signal for WM stop is feasible here, so that the weaving machine can be stopped when the sensor and control unit recognize that the signal in the current weave cycle of the reference signal inadmissible. The latter usually means that a weft thread was not entered properly.

In one embodiment of the invention, input facilities are provided on the device with which the operator can specify a learning phase during which the first reference signals are determined.

Figur 1

Schematische Darstellung einer Ausführungsform der erfindungsgemäßen Vorrichtung zur Durchführung des Verfahrens

Figur 2

Beispielhafte Signalverläufe am Ausgang eines Sensors während der Durchführung des erfindungsgemäßen Verfahrens

In a further embodiment, input possibilities are provided by means of which the operator can specify the number of weaving machine looms which should underlie the calculation of the reference signal for each weft thread to be entered in the weaving pattern.

FIG. 1

Schematic representation of an embodiment of the device according to the invention for carrying out the method

FIG. 2

Exemplary signal curves at the output of a sensor during the implementation of the method according to the invention

FIG. 1 shows an embodiment of the device according to the invention.

Shown is an example of the weft insertion on an air-jet weaving machine.

However, the device according to the invention is also in weaving machines with other entry principles - e.g. Water jet machines - used in which the monitoring of Fadenanzunft is made by a sensor at the end of the entry path.

A weft thread 1 is selected from a number of weft threads 1,2,3 ... n web pattern dependent withdrawn from supply reels by means of prewinders 9 and entered, for example by main nozzles 10 and auxiliary nozzles 13 in the channel of a Profilriets 12. The profile sheet 12 is in the range of warp threads, not shown, which form a shed. The weft insertion path 5 extends in In this case, from the main nozzles 10 across the width of the shed away to the outermost position, which can take the front weft end after a successful weft insertion.

The arrival of the weft 1 at the end of the weft insertion path 5 is monitored by one or more sensors 4 located in the region of the end of the weft insertion path.

The sensor 4, which may also contain its own, not shown, electronics, generates a waveform 6, which is passed on to an electronic control unit 7 on. In the control unit 7, the signal profile 6 is evaluated with the method according to the invention described above.

Depending on the result of the evaluation, the control unit 7 optionally outputs a signal 11 to various weaving machine components 8, 9, 10, 13. If necessary, a signal can also be returned to the sensor 4 or to the electronics connected to the sensor.

FIG. 2 shows measured waveforms 6.1, 6.2, 6.3 ..... 6.n at the output of a sensor 4 for monitoring the yarn arrival of weft yarns 1,2, 3 ... n during several weaving cycles of a loom.

For each web pattern-dependent entry cycle of a weft thread 1, 2, 3 ... n into the shed results in another typical course of the signal 6, which generates the sensor 4, when the weft thread 1 passes through the region of the sensor. When using similar weft threads in successive weaving cycles, the waveforms will differ less or not at all.

The FIG. 2 shows several of these passage processes with their respective typical waveforms 6.1, 6.2, 6.3 ..... .. 6.n in time sequence of several webmusterabhängig registered different weft threads 1, 2, 3 ... n.

In the present case, the behavior is shown by way of example on an air-jet loom, in which an opto-electronic sensor 4 is arranged at the exit of the channel of a profile reed 12.

Each individual signal course 6.1, 6.2, 6.3... 6.n indicates the arrival of the respective weft thread 1, 2, 3... N at the end of the entry path and thus the successful weft insertion. If the weft insertion is incorrect, the relevant signal is missing. The undesirable, but unavoidable entry of fiber dust or fluff results in a signal curve 6, which depends on the one for the weave pattern weft thread typical signal waveform deviates - either in height and / or in terms of the timing of the signal. This is detected in the evaluation of the waveforms 6 with the aid of the inventively determined reference signal and the process is interpreted by the control unit 7 as improper weft insertion.

Reference numeral list

1,2, 3 ... n

weft

4

sensor

5

Schusseintragsweg

6

Signal curve of the sensor

7

Electronic control unit

8th

main drive

9

yarn storage

10

Main nozzles for weft yarns 1,2,3 ... n

11

one of several possible signals

12

profile Riet

13

auxiliary air jets

Claims (11)

1. A method for monitoring the thread arrival during the insertion depending on the weaving pattern of different weft threads (1, 2, 3 ... n) into the shed of a weaving machine, wherein an inserted weft thread (1) is monitored by an opto-electronic sensor (4) in the area of the end of the insertion path (5), which depending on different properties crucial for the monitoring of the weft thread (1) and/or depending on the behavior of the weft thread (1) during the passage through the sensor (4) generates different electrical signal profiles (6.1, 6.2, 6.3 ... 6.n), which are characterized by different levels and different points in time and which are evaluated by at least one electronic control unit (7), characterized in that a reference signal typical for each weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern is calculated and stored by means of the control unit from several signal profiles (6) of the passage processes generated by weft insertions into the weaving machine during the passage of the respective weft threads (1) through the sensor (4) and that within a weaving cycle of the weaving machine (WM) the actual signal profile (6) of the passage process, which is generated during the passage of a weft thread (1) through the sensor (4), is electronically compared by means of the control unit (7) with the stored reference signal of the weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern in said weaving cycle.
2. A method according to claim 1, characterized in that the reference signal is calculated and stored in the form of a signal profile.
3. A method according to one of claims 1 to 2, characterized in that the control unit (7) depending on the result of the evaluation emits at least one of various possible signals (11), wherein a possible signal (11) is the signal for WM stop.
4. A method according to claim 3, characterized in that
   during a specifiable learning phase of the weaving machine a stop signal (11) generated on the basis of the evaluation is not transmitted to the weaving machine components (8, 9, 10, 13) participating in the weaving process.
5. A method according to one of claims 1 to 4, characterized in that the calculation of the reference signal for each weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern is regularly repeated during the ongoing weaving operation by means of the control unit (7) and thus the reference signal is up-dated on an ongoing basis.
6. A method according to one of claims 1 or 5, characterized in that for each weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern the number of weaving cycles is specified, which underlies the calculation of the reference signal for said weft threads (1, 2, 3 ... n).
7. A device for monitoring the thread arrival during the insertion depending on the weaving pattern of different weft threads (1, 2, 3 ... n) into the shed of a weaving machine, having at least one opto-electronic sensor (4) mounted in the area of the end of the insertion path (5) of such a nature that depending on different properties crucial for the monitoring of the weft thread (1) and/or depending on the behavior of the weft thread (1) during the passage through the sensor (4) different electrical signal profiles (6.1, 6.2, 6.3 ... 6.n) are generated, which are characterized by different levels and different points in time, and having an electronic control unit (7) with control elements, which make possible the insertion of different weft threads (1, 2, 3 ... n) depending on the weaving pattern and which is connected by signal transmission with the at least one sensor (4) in such a manner, that the control unit (7) is able to evaluate the signal profiles (6) of the sensor, characterized in that the control unit (7) is equipped with such hardware and software, that for weft threads (1, 2, 3 ... n) to be inserted depending on the weaving pattern a reference signal typical for the respective weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern can be calculated and stored from several signal profiles (6) of the passage processes generated by weft insertions in the weaving machine during the passage of the respective weft thread (1) through the sensor (4) and
   for one weaving cycle of the actual signal profile (6) of the passage process, which is generated during the passage of a weft thread (1) through the sensor (4), can be compared electronically by means of the control unit (7) with the stored reference signal of the weft thread (1, 2, 3 ... n) to be inserted in said weaving cycle depending on the weaving pattern.
8. A device according to claim 7, characterized in that at least one of various possible signals (11) can be transmitted by the control unit (7) depending on the result of the evaluation, wherein a possible signal (11) is the signal for WM stop.
9. A device according to claim 8, characterized in that the electronic control unit (7) has input means, by which the operator can specify a learning phase of the weaving machine, during which a signal (11) generated due to the comparison is not transmitted for WM stop.
10. A device according to one of claims 7 to 9, characterized in that the calculation of the reference signal for each weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern can be repeated regularly by means of the electronic control unit (7) during the ongoing weaving operation and thus the reference signal can be up-dated on a regular basis.
11. A device according to claim 7 or 10, characterized in that the control unit (7) has means, by which the operator can specify the number of weaving cycles of the weaving machine, which should underlie the calculation of the reference signal for each weft thread (1, 2, 3 ... n) to be inserted depending on the weaving pattern.

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