EP3460113A1 - Method for incorporating a warp knitting machine and warp knitting machine - Google Patents

Abstract

The invention relates to a method for incorporating a warp knitting machine (1) with a new pattern, in which threads (4) of a warp are pulled into guide needles (2) and at least one course is formed by interaction of the guide needles (2) with knitting needles (3) ,

One would like to facilitate the incorporation of a warp knitting machine.

For this purpose, it is provided that a tension of the tapered threads (4) is determined and limited to a predeterminable maximum value.

Description

The invention relates to a method for incorporating a warp knitting machine with a new pattern, in which one pulls threads of a chain in guide needles and forms by interaction of the guide needles with knitting needles at least one course.

Furthermore, the invention relates to a warp knitting machine with at least one main shaft, at least one guide bar, at least one knitting needle bar, a thread balancing device, at least one delivery drive and at least one fabric take-off.

For a known knitwear, which can also be referred to as "pattern" for short, the necessary data is generally available. The data includes, among other things, the laying, a size for the thread inlet and a size for the fabric removal. So if a warp knitting machine must be incorporated, for example, because a warp beam has been completely processed or retrofitted the warp knitting machine to another pattern The operator pulls the threads into the guide needles, creates one or more courses, pulling the threads taut by hand after each stitching operation, then activates the delivery drive with a predetermined thread break value, allowing the machine to produce a series of further stitches until you are able to deduct the resulting knitted fabric with the fabric, then turns on the fabric and can start production.

However, if you want to create a new pattern, you will not or not necessarily have all the data you need. As a rule, the laying is predetermined, i. the course of movement of the guide needles against the knitting needles. However, the thread entry must be determined empirically, for example. For this purpose, a certain experience and a corresponding feeling of the operator are required. Each step involves a risk of operator error and lack of expertise. This can cause damage to the active elements and / or to the process material, for example the yarn. The incorporation is therefore time consuming and costly.

The invention has for its object to facilitate the incorporation of a warp knitting machine in a new pattern.

This object is achieved in a method of the type mentioned in that it determines a voltage of the incoming filaments and limited to a predetermined maximum value.

The limitation of the thread tension avoids excessively high thread tensions. This considerably reduces the risk of damage to the knitting tools or the thread material. In addition, limiting the tension of the incoming filaments allows one Limitation in terms of the freely selectable parameters, so that the operator can only work in a limited work area. This further facilitates the incorporation, because the possibilities of variation and thus also the possibilities of error can be kept small. The tension of the circulating threads is in this case preferably determined on a component that does not directly thread the thread. It is not the tension of a single thread, but a tension in the totality of the threads provided by a tree.

Preferably, the course is formed in creeper. So you can operate the warp knitting machine at a very low speed, as long as you incorporate the new pattern. The tensions of the threads are practically independent of the working speed of the warp knitting machine.

Preferably, the voltage is determined at a time when the guide needles have reached their point of reversal behind the knitting needles. Here is the maximum deflection of the guide needles. At this point, the distance of the various active elements is greatest. Accordingly, the tension of the threads is greatest here. It is sufficient to determine the tension here and to make it the basis of further action.

Preferably, the voltage is adjusted by controlling a delivery drive. The delivery drive actively drives a warp beam from which the threads of the warp are pulled. In the later production mode, in which the knitted fabric is produced continuously, the delivery drive is operated with a constant yarn shrinkage value. The yarn infeed value is usually stated in "mm / R", ie millimeters per rack. One of the tasks of incorporating a warp knitting machine with a new pattern is to determine an appropriate thread break value.

This yarn shrinkage value can be determined by presetting the voltage and operating the delivery drive in a closed loop in such a way that the voltage is reached but not exceeded. If the delivery drive gives off too much thread length per knitting operation, the tension is too low. If the delivery drive delivers too little thread length per stitching operation, the tension is too high. Accordingly, one can adjust the "delivery speed" in the delivery drive with a relatively simple control to the correct thread run-in value. It is not absolutely necessary here that the delivery drive already runs continuously at this stage of incorporation. It can also be operated intermittently, so deliver some thread for a short time and then stop again. This should be avoided only excessively large voltage spikes. Incidentally, during a stitch formation process, quite occasionally even a very slight or no tension can prevail in the threads. The delivery drive is operated in each case only in a positive drive direction, ie in a direction in which it emits threads.

Preferably, a cloth take-off is switched on and, after switching on the fabric take-off, the regulation of the delivery drive continues for a predetermined time. Turning on the fabric removal results in a change in the appearance of the knitwear. Without a product take-off, the individual courses are, so to speak, produced "on block". The stitches of the individual rows of stitches are practically adjacent to one another in the production direction of the knitted fabric. Turning on the fabric removal then results in a slightly different appearance. Depending on the speed with which the fabric take-off is operated, the result is a looser or firmer knitwear structure. The control of the delivery drive then also has an influence on the structure of the knitted fabric, because if the delivery drive delivers a greater thread length per stitching process, then one can achieve a looser knit fabric than in the case of less thread length per stitching process. After switching on the fabric removal, the operator can then check whether the knitted fabric meets the requirements or wishes. If this is not the case, it can change the voltage specification.

Preferably, a yarn inlet value of the delivery drive is displayed. The yarn tension results in a yarn shrinkage value, for example mm / R, ie millimeters per rack. If the knitted fabric has the desired appearance and the desired haptics, you can view this thread running value to reuse it in later production operations of the same pattern. The display can be done visually via a display. However, the display can also consist of printing out or otherwise storing the yarn infeed value. It is only important that the thread run-in value later, i. in a new production of the same pattern, is available and can be entered into the knitting machine.

Preferably, one predetermines the predetermined maximum value as a fraction of a basic value. The basic value is known for each machine and can be specified by the manufacturer. It results, for example, from measurements on the respective warp knitting machine, whereby fluctuations can also be taken into account here. For example, you can then specify a certain percentage of the basic value as voltage. So no specification of an absolute value is required.

The object is achieved in a warp knitting machine of the type mentioned above in that a yarn tension measuring device is connected to a control device which regulates the delivery drive in a learning phase.

Thus, as explained above in connection with the method, the thread tension measuring device can be used to determine the thread tension of the threads of the chain and make this tension the basis of the setting of the thread running value of the delivery drive. Thus, an overload of the active elements and the thread material is avoided on the one hand. On the other hand, the operator has an easy way to change the look and feel of the resulting knitwear. He only has to change a setpoint with which the control device controls the delivery drive.

Preferably, the thread tension measuring device is arranged on the thread balancing device. The thread balancing arrangement is required in the production of a knitted fabric in a warp knitting machine, because there is a fluctuating thread consumption in a stitch formation process. The fluctuations within this thread consumption can be compensated via the thread balancing device. You can now use this thread balancing device in a simple way also to determine the thread tension. A "measurement" in the sense of a numerical result is often unnecessary. The thread tensioning device can also be arranged on the attachment of the thread balancing device.

Preferably, the yarn tension measuring device determines a total tension of a plurality of yarns. This results in a certain balance over the width of the warp knitting machine. The influence of a single thread and its tension is thus kept small, while the total tension of several or even all threads gives a meaningful size.

It is preferred that the yarn tension measuring device determines a tension on a crosshair. The reticle is in the simplest case a spring-mounted rod, passed over the threads of the chain before they enter the thread guide opening of the guide needles. The crosshair has its greatest deflection when the guide needles are in their reversal point behind the knitting needles. At this moment, the maximum thread tension can be determined. The thread tension is in this case preferably determined on a fixed part, for example in a region between a spring arrangement, which carries the crosshairs, and the frame of the warp knitting machine.

Preferably, the yarn tension measuring device is synchronized with the main shaft. The yarn tension measuring device can then determine the corresponding voltage exactly at the moment indicated above, in which the guide needles have their greatest distance from the knitting needles.

Fig. 1

eine stark schematisierte Ansicht von Teilen einer Kettenwirkmaschine, und

Fig. 2

eine schematische Darstellung von Spannungsverläufen.

The invention will be described below with reference to a preferred embodiment in conjunction with the drawings. Herein show:

Fig. 1

a highly schematic view of parts of a warp knitting machine, and

Fig. 2

a schematic representation of voltage curves.

A warp knitting machine 1, parts of which are shown, has guide needles 2, which are arranged on a guide bar, not shown. Furthermore, the warp knitting machine knitting needles 3, which are arranged on a knitting needle, not shown. In operation of the warp knitting machine, the guide needles 2 and the knitting needles 3 are moved relative to each other to form stitches of a knitted fabric. The relative movement in this case has sections in which the guide needles 2 are moved through alleys between knitting needles 3, and Sections in which the guide needles are moved parallel to the longitudinal extent of the knitting needle bar.

In such a movement threads 4, which are deducted from a warp beam 5, processed into stitches of knitwear.

The threads 4 are passed to a trained as a rod 6 reticle. The rod is mounted on a spring arrangement 7. The spring arrangement 7 allows a certain mobility of the rod 6, when the tension of the threads 4 changes. Such a voltage change occurs at least once per stitching cycle, as is apparent Fig. 2 can be seen.

Fig. 2 shows a first curve 8, which shows the tension of a single thread 4, and a second curve 9, which represents a corresponding voltage curve of the entire chain. The voltage curve shown in the curve 9 can be determined from the movement of the rod 6. For this purpose, a sensor 10 is arranged on the spring assembly 7, which determines the voltage of the spring assembly 7 and thus the force applied by the rod 6 on the spring assembly 7 force. Of course, it is also possible to use another sensor in order to determine the tension of the chain formed by the threads 4. The sensor 10 may for example be formed by a strain gauge, which is arranged between a frame 18 of the warp knitting machine and a holder 19 of the spring arrangement 7 fastened to the frame 19. The sensor is thus located on a stationary part and it is located outside of an immediately thread-guiding element of the warp knitting machine.

The sensor 10 is connected to a control device 11. The control device 11 is connected to a delivery drive 12 of the warp beam 5.

The warp knitting machine 1 has a main shaft 13. The main shaft 13 is responsible for most movements of the knitting tools. In particular, it controls the movements of the guide needles 2 and the knitting needles 3. In simple terms, a rotation of the main shaft 13 causes a stitch forming operation in most cases, so that one course is produced per revolution of the main shaft 13.

A rotation angle sensor 14 detects the rotational position of the main shaft 13 and also reports it to the control device 11.

Not shown in detail is a fabric take-off, with which the knitted fabric formed can be removed from the working area formed by the guide needles 2 and the knitting needles 3.

When a warp knitting machine is put into operation, the threads 4 are drawn into the guide needles 2. This is usually done with a developed guide bar, in which the guide needles 2 are more accessible. After pulling in the threads, the guide bar is moved to its normal working position and mounted there. An operator then slowly sets the machine in motion and first checks whether the guide needles 2 can pass through lanes between the knitting needles 3 without colliding. If necessary. a correction is required.

The operator then first performs a first stitching operation. Thereafter, the threads 4 are tightened by hand. This is followed by one or more further stitch-forming operations until at least one over the working width of the Warp knitting machine 1 continuous stitching has been formed. Between each stitching operation, the threads 4 are tightened by hand.

If a continuous stitch formation has taken place, the delivery drive 12 of the warp beam 5 is put into operation. The warp beam 5 then provides the threads 4. The stitches are then first formed on a block, i. they are close together. Thereafter, the product deduction, not shown, is put into operation and the production of the product can begin.

However, this presupposes that certain parameters of the production of the knitted fabric are known, in particular a value for the so-called yarn inlet, which is typically specified in mm / R, ie millimeters per rack. In addition to the actual laying and the mesh density, which can be influenced by the fabric removal, the thread entry is an important value in the production of knitwear.

If a new pattern is to be created, the value of the thread infeed is not available. The thread entry is adjusted with experience and feeling of the operator. At each step, there is a risk of operator error and lack of expertise. This can result in damage to the active elements, ie the guide needles 2 and the knitting needles 3. In addition, the threads 4 can be damaged.

To alleviate this problem, it is determined with the help of the sensor 10, a voltage of the incoming filaments 4 and reports this actual voltage to the controller 11 on. The controller 11 compares the actual voltage with a predetermined target voltage and now controls the Delivery drive 12 so that this target voltage, which represents a predeterminable maximum value is not exceeded.

If the delivery drive 12 is controlled so that it provides more threads 4, so a greater thread length per rack, then the voltage drops. If the delivery drive 12 is driven so that it delivers fewer threads, so a smaller thread length per rack, then the voltage increases. Through this automated procedure, one can achieve that the warp knitting machine, as it were, approaches the correct value of the thread inlet by itself.

This "learning process" continues when the fabric take-off is turned on and the stitches become larger. Thus, a larger length of the threads 4 is needed for each stitch. Accordingly, the delivery drive must rotate the warp beam 5 slightly faster to provide a greater length of the yarns 4 per stitch forming operation. Again, the voltage is determined and the delivery drive 12 is controlled so that a maximum voltage is not exceeded.

The voltage does not have to be entered as an absolute value. Each warp knitting machine 1 usually has a basic value, which can be predetermined by the manufacturer, for example, or can be determined when the warp knitting machine is put into operation for the first time. The operator can then via an input device 15, for example, a percentage of this basic value, that is, a fraction specify, to set the maximum voltage. The operator can then visually or by feeling check whether this tension value has given the desired quality of knitwear. If this is not the case, the percentage value can be changed via the input device 15.

Once the knitted fabric has been produced with the satisfactory quality, the value of the yarn inlet can be displayed via a display device 16. The display device is shown schematically here. It is not necessary to use a display or a printer here. It is also possible to store the value of the thread entry only, so that the stored value is then available for later production operations.

With the value of the thread entry later knitwear, which contain the same pattern, can be produced.

The described process preferably takes place in crawl, so that the operator can continuously monitor at slow speed, whether the knitted fabric is actually produced with the desired appearance and the desired feel.

The crosshairs with the rod 6 and the spring device 7 forms a thread balancing device, which is required in operation to compensate for the fluctuating in a stitch forming process thread consumption. You can now also use them to determine the tension of the threads continuously.

Like from the curves of Fig. 2 can be seen, the tension of the threads 4 varies considerably in a stitch formation process. This is because in a stitch forming process, the thread consumption also fluctuates. The tension is greatest when the guide needles 2 are at a reversal point behind the knitting needles 3, on the side of the hook 17 of the knitting needles 3. Here, the guide needles 2 opposite the knitting needles 3, the largest deflection. By the rotation angle sensor 14, which detects the rotational angular position of the main shaft 3, it is now possible to detect this position of the guide needles 2, so that the Control device 11 detects the corresponding voltage value only at this time. The control device 11 therefore forms, as it were, a snapshot of the voltage at a point in time at which the main shaft 13 is in a predetermined angular position, and only compares the voltage at this time with the predetermined or predeterminable maximum value.

Claims (12)

Method for incorporating a warp knitting machine (1) with a new pattern, in which threads (4) of a warp are drawn into guide needles (2) and at least one course is formed by cooperation of the guide needles (2) with knitting needles (3), characterized in that a tension of the tapered threads (4) is determined and limited to a predeterminable maximum value. A method according to claim 1, characterized in that one forms the row of stitches in the crawlspace. A method according to claim 1 or 2, characterized in that one determines the voltage at a time at which the guide needles (2) have reached their reversal point behind the knitting needles (3). Method according to one of claims 1 to 3, characterized in that adjusting the voltage by regulating a delivery drive (12). A method according to claim 4, characterized in that one turns on a fabric take-off and after switching on the fabric take-off, the regulation of the delivery drive (12) continues for a predetermined time. Method according to one of claims 1 to 5, characterized in that one indicates a yarn inlet value of the delivery drive (12). Method according to one of claims 1 to 6, characterized in that one predetermines the predetermined maximum value as a fraction of a basic value. Warp knitting machine (1) with a main shaft (13), at least one guide bar, a knitting needle bar, at least one thread balancing device (6, 7), at least one delivery drive (12) and at least one fabric take-off, characterized in that a thread tension measuring device (10) with a control device (11), which regulates the delivery drive (12) in a learning phase. Warp knitting machine according to claim 8, characterized in that the thread tension measuring device (10) on the thread balancing means (6, 7) is arranged. Warp knitting machine according to claim 9, characterized in that the yarn tension measuring device (10) determines a total tension of a plurality of yarns (4). Warp knitting machine according to claim 10, characterized in that the yarn tension measuring device (10) determines a voltage to a crosshair (6). Warp knitting machine according to one of claims 8 to 11, characterized in that the yarn tension measuring device (10) with the main shaft (13) is synchronized.

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