JP2004003105A - Method and device for continuously inserting weft yarn into shed of loom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a device for performing a method for continuously inserting a weft yarn into the shed of an air nozzle type loom for adjusting a weft yarn separation time point necessary for an optimal weaving result simply and surely during the operation of weaving so as to maintain the same. <P>SOLUTION: This method and device for continuously inserting the weft yarn in the shed of the loom includes at least one main nozzle 3 and a separation device 4 which has a signal-controlling type driving device 5 independent from a driving device of the loom, and equipped with a monitoring device for monitoring the state of a formed fabric 10, and a measuring device 12 and a computer 6 for calculating the separation time point of part 9a of the weft yarn 9 inserted into the shed from the weft yarn storage part 1, forming a corrected controlling signal according to the signal formed in the monitoring device and measuring device by the computer and supplying the controlling signal to the driving device 5 of the separation device 4 so as to control the separating device 4 changed at the time point of weft insertion performed next by once or multiple number of times. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a method for continuously inserting a weft into a shed of a loom according to the superordinate concept part of claim 1, wherein each of the wefts drawn from a weft storage unit is blown by a blow air (Blasluft; injection). Air), separating the weft after insertion and after pressing with a bar, and changing the time of this separation by controlling the separating device based on signals.
[0002]
The invention also relates to a device for continuously inserting a weft thread into the shed of a loom, in particular for carrying out the method according to the invention.
[0003]
[Prior art]
Such a method is known from EP 0284766. As is generally known, in an air nozzle type loom, a weft is supplied from a weft storage unit (delivery bobbin) to a main nozzle via a front spool. The weft is inserted or passed into the shed of the loom by an air jet supplied through the main nozzle. As soon as the weft is neatly inserted and protrudes from the edge of the fabric opposite the main nozzle, the sheath is pressed down and then the weft is immediately separated from the weft storage. For this purpose, a separating device is arranged between the main nozzle and the fabric adjacent to the main nozzle. The end of the weft connected to the weft storage, which is outside the fabric, is held by the holding air in the main nozzle until the next weft insertion.
[0004]
According to EP-A-0284766, the separating device is driven by an adjustable adjustable drive, which is a separate drive independent of the main drive of the loom. The separation device is driven by, for example, an electric step motor, and a control signal of the step motor is supplied by a computer. The separating device can then be operated at different times under computer control, or the operation can be interrupted to prevent the inserted weft from being separated. Of course, it is known that the optimal time for separation is based on the type of weft used, and also on the weaving cycle, the weaving pattern, the operating state of the loom and the flight of the weaving yarn in the shed. ing. These influence values are supplied to the computer as so-called weaving parameters, from which the computer forms control signals for the drive of the separating device, and thus the exact time at which the separating device is operated. Stipulated. When a defective weft insertion is located by the weft monitoring device, the separating device prevents the separation of the weft yarn, thereby removing the defective weft yarn. The weft monitoring device necessary for this is provided at the fabric edge facing the main nozzle.
[0005]
Another known weft insertion device is described and illustrated in EP-A-0 953 664. This known device relates to a loom in which weft is inserted into a shed using a transfer gripper and a hold gripper. In this known device, the separating device for the weft is likewise controllable independently of the loom drive and is connected to a holding device. The holding and separating device is controlled in relation to a signal formed based on the measured yarn tension. A special sensor is provided for this purpose. The separating device is operated when the holding force of the weft obtains a predetermined value that cannot be too large or too small. Such a control compensates for the disadvantage that the yarn clamping of the transfer gripper acts differently depending on the type of the weft yarns, which in turn results in yarn loss and fabric defects.
[0006]
Therefore, the device disclosed in EP-A-0 953 664 needs to calculate an absolute measurement of the tensile stress in the weft. Methods for calculating the mechanical tensile stress of a weft during a weaving operation are known. Measuring the tensile stress taking into account the constantly high speed of the loom always has more significance. This is because it takes full advantage of the mechanical properties of the weft. However, accurately defining the tensile stress of the weft during operation is relatively expensive.
[0007]
The method and apparatus of the type described at the outset, on which the invention is based, have the disadvantage that the starting time of the separating device does not in any case correspond to the actual separating time. That is, the point of separation deviates from the theoretically desired adjustment value. This is because the weft yarns are arranged at various different positions in the area of the separation device according to the plurality of main nozzles which are spatially arranged one above the other and side by side. In addition, spatially often very complex thread guides in the area of the separating device are also responsible for the deviation. Another cause is that the drive of the separation device is affected by electromechanical fluctuations or rotation speed fluctuations based on the type of weft. Furthermore, the scissors forming the separation device are worn away. These causes change during the operation of the loom and are affected by the fluctuations.
[0008]
If the time at which the inserted weft is cut off from the weft storage deviates from the theoretically desired time or fluctuates during operation, inconveniences occur during the edge formation of the fabric. The edges of the fabric will be uneven, and such uneven edges will be particularly noticeable in fabrics having inserted edges. Therefore, it is desired to calculate and display the separation point during the weaving operation and to keep it constant over as wide a range as possible.
[0009]
[Patent Document 1]
European Patent No. 0284766 [Patent Document 2]
EP-A-0 953 664 [0010]
[Problems to be solved by the invention]
It is an object of the present invention to improve the method and the device described at the outset to adjust and maintain, during the weaving operation, the weft separation time required for optimum weaving results as simply and reliably as possible. Is to be able to do it.
[0011]
[Means for Solving the Problems]
According to the method of the present invention that solves this problem, the time at which the inserted weft is separated at the time of inserting the first weft is calculated, and based on the calculated value and obtained at this time. Depending on the weaving result, a signal for controlling the separating device is formed for one or more subsequent weft insertions.
[0012]
In this case, the term “weaving result” means that the edges of the woven fabric are formed in order, that is, uniformly.
[0013]
【The invention's effect】
According to the method of the present invention, the operator operating the loom allows the separating device of the loom to form the best possible weaving result, in particular the weaving edge, based on logical considerations and preliminary tests. Can be adjusted to a first value. If the experiment indicates that the first adjustment does not produce the desired result because the actually obtained separation time is offset from the logically determined time, the separation device will Controlled by the desired signal corresponding to the determined time, the time for the next weft is shifted forward or backward. The condition of the fabric edge, which is adjusted after the signal change, makes it possible to determine whether the judgment is correct. This process is repeated or performed in many steps until a fabric with regularly formed uniform edges is obtained and other improved weaving properties are obtained.
[0014]
During operation, the method can be carried out automatically, since it is easily possible to continuously monitor the fabric edge with optimal measuring methods. The point at which the first weft is separated from the weft storage can also be calculated automatically and reliably by an optical method. It is sufficient for this purpose to optically monitor the area between the separating device and the shed through which the weft to be separated later passes.
[0015]
However, according to a first advantageous embodiment of the method of the invention, the time of separation is determined by determining when the mechanical tensile stress in the weft changes dramatically as a result of the separation. did. In this case, a known method for measuring the tensile stress in the weft is used for confirming the point at which the tension action of the weft hit by the hook is interrupted and calculated relatively easily. The part of the weft leading to the reservoir is still under the influence of the holding air holding the yarn end in the main nozzle until the next weft insertion. It is not necessary to calculate the exact absolute value of the tensile stress in a costly manner.
[0016]
Advantageously, the mechanical tensile stress in the region of the weft present between the front spool and the main nozzle is calculated. This measuring point offers a particularly high measuring accuracy. This is because this measurement point is located closest to the separation point and is not affected by disturbances.
[0017]
In the method according to the invention, almost all known methods can be associated for calculating the mechanical tensile stress in the weft. However, it is particularly advantageous if the continuous measurement of the tensile stress is performed in a known manner, for example by means of a piezoelectric element. This method of measurement is particularly economical / accurate in connection with the method of the invention.
[0018]
In particular, the object of the device according to the invention for carrying out the method according to the invention is likewise to provide a device for continuously inserting wefts into the shed of an air nozzle loom.
[0019]
According to a feature of the device of the invention that solves this problem, at least one main nozzle and a separating device are provided, the separating device being an independent, signal-controlled drive independent of the drive of the loom. Having a device, a monitoring device for monitoring the state of the formed fabric, a measuring device and a computer for calculating the time when the part of the weft inserted in the shed is separated from the weft storage unit Wherein the computer forms a modified control signal in response to the signals formed in the monitoring device and the measurement device, and supplies the control signal to the drive of the separation device; It is characterized in that the separating device is controlled at the changed time during one or more subsequent weft insertions.
[0020]
According to an advantageous embodiment of the invention, a monitoring device is provided for monitoring the condition of the manufactured fabric, the monitoring device comprising an edge calculator for calculating the condition of the fabric edge facing the main nozzle. Consists of equipment. For example, an optical measurement makes it possible to easily confirm such an edge calculation as to whether the formed fabric actually has edges formed uniformly. The edge calculator then sends the result of this measurement to a computer, which forms a possibly modified control signal in response to the measurement and changes the control time of the separating device.
[0021]
According to another embodiment of the invention, the measuring device for calculating the weft separation comprises a calculator for calculating the point in time at which the mechanical tensile stress in the weft changes dramatically as a result of the separation of the weft. Have been. That is, the weft inserted into the shed is separated only when the length is pressed and the weft is fixed. The weft inserted in this manner is under strong tensile stress, which is reduced as soon as the weft is separated on the insertion side of the shed. The part of the weft, still connected to the weft storage, is under the influence of the holding air holding the yarn end in the main nozzle until the next weft insertion. That is, it is not important to calculate an accurate absolute value of the yarn tension.
[0022]
An advantageous location for arranging the measuring device for calculating the weft separation is just before the main nozzle in the yarn running direction. Since this location is, on the one hand, well accessible for measurement and on the other hand close to the separation point of the weft, a good measurement result and a built-in environment that is structurally simple to implement are provided here. can get.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be specifically described with reference to examples shown in the drawings.
[0024]
In the drawing, a bobbin is indicated by reference numeral 1, and a weft storage unit is present on the bobbin 1. As viewed in the running direction of the weft 9, a front spool (Vorspeller) 2, a main nozzle 3, and a separation device 4 are continued. The separating device 4 is driven by a driving device 5. The drive 5 is independent and independent of the loom's central drive. The drive device 5 is generally an electric drive motor controlled by a computer 6. The reference numeral 8 indicates the warp of the fabric 10 to be manufactured, in which case the sheath 7 replaces the part 9a of the weft 9 to be newly introduced into the fabric with the fabric 10 already formed. Used for pressing. A monitoring device is indicated by the reference numeral 11, which continuously monitors, for example, at least the inlet side or the outlet side of the shed and how uniformly the fabric edge facing the main nozzle 3 is formed. To find out if they are.
[0025]
A measuring device 12 is arranged between the front spool 2 and the main nozzle 3, and this measuring device 12 is connected to the computer 6 by a signal line 13a. Another signal line 13b is used to simultaneously send the signal transmitted from the monitoring device 11 to the computer 6.
[0026]
The measuring device 12 continuously measures the mechanical tensile stress in the weft 9. A measuring device of this type works, for example, according to the principle of a piezoelectric element (piezo element). Such measuring devices are well known to those skilled in the art and need not be described in detail. This is the same for the separation device 4. This is because, for example, rotary cutters or scissors consisting of stationary and movable parts are known to those skilled in the art. The only important thing is that the driving of the scissors is controlled at a precisely selectable point in time, so that the penetrated weft is cut off.
[0027]
The principle of the present invention is not limited to the configuration in which one weft is inserted. The device according to the invention comprises, in a general manner, a configuration in which a plurality of main nozzles arranged spatially next to one another and one above the other are multiplexed.
[0028]
The device described above works as follows.
[0029]
Compressed air is used between the warp yarns 8 of the sheaves or sheaves (Webfach) until the weft yarn 9 unwound from the bobbin 1 is guided through the main nozzle 3 and protrudes from the opposite edge of the formed fabric 10. Let through. At the same time, the sheath 7 is pressed against the weave in the shed, thereby retaining the weft-inserted portion 9a. Next, the driving device 5 of the separation device 4 is controlled by the signal supplied to the computer 5, and the separation device 4 is operated. This process is repeated many times without changing the signal of the computer 6.
[0030]
At the same time, for example, the monitoring device 11 provided at the fabric edge facing the main nozzle 3 always calculates the state of the formed fabric edge. In this case, the monitoring device 11 supplies a signal to the computer 6 via the signal line 13b if the fabric edge is unevenly configured or has other defects.
[0031]
During each separation (separation) step, the measuring device 12 determines the point at which the portion 9a of the weft 9 passed through the shed, that is, the passed end, is separated from the weft 9. The part 9a introduced into the mouth creates a strong tensile stress on account of the different turning points during the passage of the separating device and in particular after hitting the sheath 7, which tensile load is measured by the measuring device 12. It is calculated. After the part 9a has been cut off, this tensile stress is significantly reduced. Because, when the portion 9a is cut off, the end of the weft 9 connected to the bobbin 1 located in the main nozzle 3 is held by the holding air until the next weft insertion is performed. Because they are just Such an impulsive return movement of the yarn tension is well calculated in terms of measurement technology and forms the basis for a correction signal, which is controlled by the computer 6 in response to a signal relating to the condition of the fabric edge. Formed. A start signal changed based on the supplied signal and the obtained weaving result data for the fabric to be manufactured is formed, and the start signal is supplied to the driving device 5. Therefore, the separation device 4 is controlled at the time when the separation is changed when the next weft passes. This process is repeated until the edges of the fabric are uniformly formed on the weft outlet side.
[0032]
During the monitoring, other properties of the formed fabric are also taken into account.
[0033]
The method and apparatus of the present invention are particularly advantageous where a large number of wefts are passed in simultaneously and separated together. Since the separation process takes place at the final speed, spatially over the wefts arranged one above the other and side by side, inevitably the individual wefts are separated from the weft storage at different times. Has become. Therefore, it is necessary to find an average value for controlling the separation device. This average is obtained when the edges of the fabric are made uniform and other measurement results are satisfactory. Such a measurement result can only be obtained with the method and the device according to the invention by measuring a few wefts.
[Brief description of the drawings]
FIG. 1 is a schematic view of an apparatus for continuously inserting a weft thread into a shed of a loom according to an embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 1 bobbin (feeding bobbin), 2 front spool, 3 main nozzle, 4 separation device, 5 drive device, 6 computer, 7 mat, 8 warp, 9 weft, 9a inserted part, 10 fabric, woven product, 11 monitoring Equipment, 12 Measurement equipment, 13a, 13b Signal line

Claims (8)

A method for continuously inserting a weft into a shed of a loom. And changing the time of the separation by controlling the separation device based on the signal,
The time at which the inserted weft yarn is separated at the time of the first weft insertion is calculated, and one or more subsequent times are performed based on the calculated value and according to the weaving result obtained at this time. A method for continuously inserting a weft thread into a shed of a loom, characterized by forming a signal for controlling a separating device for inserting the weft thread. The method of claim 1, wherein the time of separation is determined by determining when mechanical tensile stresses in the weft change dramatically as a result of the separation. 3. The method according to claim 2, wherein a mechanical tensile stress in the weft is calculated in a region of the weft existing between the front spool and the main nozzle. 4. The method according to claim 2, wherein the mechanical tensile stress is determined by means of a piezoelectric element. Apparatus for continuously inserting a weft thread into the shed of an air nozzle loom, particularly for carrying out the method according to one of claims 1 to 4, separated from at least one main nozzle (3). A separating device (4) having an independent, signal-controlled driving device (5) independent of the driving device of the loom; And a measuring device (12) for calculating the point in time when the part (9a) of the weft (9) inserted into the shed is separated from the weft storage part (1). A computer (6) is provided, said computer (6) forming a modified control signal in response to signals generated in said monitoring device and in said measuring device (12), said control signal being Supplied to the drive (5) of the separation device (4) Wherein the separating device (4) is controlled at the time of change in one or more subsequent weft insertions, the weft being continuously fed to the shed of the loom. Equipment for insertion. An edge calculator (11) belonging to the monitoring device is provided, the edge calculator (11) adapted to calculate the state of the fabric edge facing the main nozzle (3). Item 6. The apparatus according to Item 5. A measuring device (12) for calculating the separation of the weft is provided, and the measuring device (12) calculates a point in time at which the mechanical tensile stress in the weft changes drastically as a result of the separation of the weft. 7. The device according to claim 5, wherein the device is adapted to: 8. The device according to claim 5, wherein the measuring device for calculating the weft separation is arranged immediately before the main nozzle in the yarn running direction.

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