TW202113184A - Method for threading after changing warp beam in warp knitting machine and warp knitting machine having corresponding function wherein interchangeable warp threads pass through the warp beam and are actively released - Google Patents

Abstract

This invention relates to a method for threading after changing a warp beam in a warp knitting machine (1), comprising the following steps: connecting an old warp thread, which passes through an eyelet (9) of a hole needle fixed to a guide comb of the warp knitting machine (1) and which is drawn into a fabric dragging device (3) of the warp knitting machine (1) to form a knitted fabric, with an interchangeable warp thread (12) belonging to a warp beam that has been newly replaced in the warp knitting machine (1); threading the interchangeable warp thread by using the fabric dragging device (3) to drag the knitted fabric, such that the old warp thread pulls the interchangeable warp thread to pass through the eyelet (9) of the hole needle (8); and, while threading the interchangeable warp thread, rotating the warp beam by means of a warp beam drive device of the warp knitting machine (1), so that the interchangeable warp thread passes through the warp beam and are actively released. The invention also relates to a warp knitting machine (1) with a function for threading after the warp beam has been changed for performing the method described above.

Description

Method for threading yarn after changing warp beam in warp knitting machine and warp knitting machine with corresponding function

The invention relates to a method for threading yarn after a warp beam is changed in a warp knitting machine.

The warp knitting machine has a knitting tool that processes the warp yarn into a textile material, so-called knitted fabric, during the knitting process. The warp knitting machine also has a plurality of bars, wherein a plurality of knitting tools are respectively arranged on each bar. Because many knitting tools can be moved at the same time with the help of one bar, many loops are formed at the same time during the knitting process. Here, this is why the warp knitting machine has a high production capacity. The knitted fabric produced by the warp knitting machine is drawn from the knitting area of the warp knitting machine by fabric pulling. In the knitting zone, the knitted fabric is processed into loops by knitting tools.

The warp yarns are generally placed on so-called warp beams. Many warp yarns are arranged parallel to each other on the warp beam. Once the warp yarn has been used up, the warp beam must be replaced in order to provide new yarn material. The warp knitting machine is stopped and the warp yarns are cut so that the warp beam can be taken out of the warp knitting machine. The cut warp yarn passes through the eye needles of the guide bar of the warp knitting machine and is guided to the knitting position and the guide bar is removed. The new warp beam was replaced. The warp yarns of the new warp beam are now pulled through the eye needles with the aid of the threading tool in groups of 20 to 40 yarns. This process is done manually. During this period, the warp beam was also manually rotated to provide a suitable amount of yarn to pass through the warp. This is more tedious and time-consuming.

Knotting devices are also known from the prior art, which connect the warp yarns to each other. Such a knotting device is disclosed, for example, by DE19504573C2. In principle, it is possible that the warp yarns of the newly replaced warp beams are tied to the old warp yarns located in the machine, so that the old warp yarns can pull the new warp yarns through the eyelets of the eye needles. In principle, it is also conceivable that the warp threads are connected in other ways. The connection points between each newly exchanged warp yarn and the old warp yarn cause a change in the warp yarn properties that are important to the knitting technology. Depending on the connection form, for example, the thickness and/or the tensile and flexural strength at the connection point changes in an unfavorable way. This change is, for example, the effective local thickness at a connection point or the warp overlap area during material or force-fit connection. The change may directly make it difficult or hinder the penetration of the thickened connection point through the eyelet of the eye needle.

In the worst case, the connection point may break when it cannot pass through eye needles or other knitting tools or cannot withstand the force that occurs when passing through eye needles. In addition, the knitting tool may be damaged at this time. When, for example, the knitting tools of one or more bars must be replaced, this can result in significant economic losses.

Therefore, the present invention is based on the following task to provide a reliable and fast working process method for threading after the warp beam is changed, which method avoids the above-mentioned disadvantages.

This task is accomplished by a method of threading the yarn after the warp beam is replaced in the warp knitting machine. The method has the following steps: connecting the old warp yarn with the replacement warp yarn belonging to the warp beam newly replaced in the warp knitting machine, and the old warp yarn The warp yarn passes through the eyelet of the eye needle fixed on the guide bar of the warp knitting machine and forms a knitted fabric that is drawn into the fabric pulling device of the warp knitting machine; the replacement warp yarn is threaded through the fabric pulling method The device pulls the knitted fabric so that the old warp yarn pulls the replacement warp yarn through the eye of the eye needle, and during the threading process of the replacement warp yarn, the warp beam drive device of the warp knitting machine is used to rotate the warp beam, so that the replacement warp yarn passes the warp beam Was actively released.

As has been proven, new warp yarns can be threaded in quickly and reliably during the working process in this way. After the warp beam guiding the old warp yarn has been taken out of the warp knitting machine and the new warp beam is installed on the warp knitting machine, the method of the present invention is started. The old warp yarns are connected with the replacement warp yarns of the newly replaced warp beams, and the form of the connection method used at this time is not important. The warp yarn connection can be carried out by means of an external connecting device or a special connecting tool, but it can also be carried out by means of a device belonging to a warp knitting machine. The fabric pulling device pulls the knitted fabric from the knitting area of the warp knitting machine. As a result, the replacement warp yarn is pulled through the eyelet of the eye needle.

In order to prevent the warp yarn from being excessively loaded in the area of the eyelet, according to the present invention, the warp beam is rotated by the warp beam driving device at the same time. According to the present invention, the warp beam drive device may be a motor connected to the warp beam. According to the present invention, the aforementioned method can be controlled by the control device of the warp knitting machine.

The method of the present invention has the following advantages: the downtime of the warp knitting machine is significantly shortened compared with manual threading of the warp yarn through the eye needle. The personnel requirements and yarn consumption when changing the warp beam are reduced. In addition, according to the present invention, for the first time, it is allowed to use the connecting device in a warp knitting machine, where the lowest error rate is obtained when threading the yarn.

According to an embodiment of the present invention, each old warp yarn has a first section and a second section, the first section is a part of the finished knitted fabric, and the old warp yarn exists as an unknitted individual yarn in the second section. When the knitted fabric is drawn, the second section of each individual yarn is also drawn at the same time. Preferably, the old warp yarns are respectively connected to the replacement warp yarns in the area of their second section.

The drawing of the knitted fabric and the operation of the warp beam driving device are preferably performed synchronously, so that the threading speed of the old warp yarn through the eye needle hole caused by the drawing of the knitted fabric is consistent with the yarn supply speed of the warp beam for releasing the replacement warp yarn. This means that the adjustment is made such that the threading speed and the yarn feeding speed are at least approximately the same and/or the same in terms of time average. When the yarn feeding speed and the threading speed are at least approximately the same, a sufficient amount of yarn is always supplied through the warp beam. In order to realize the corresponding adjustment, the yarn supply speed can be determined according to the present invention according to the state of the warp beam and its speed. In order to determine the state of the warp beam, according to the present invention, the thickness of the fabric roll on the warp beam can be measured. The threading speed can be determined in a similar manner according to the present invention. According to the invention, it is also possible that known warp data, for example related to the thickness of the fabric roll, are used for the calculation.

The method of the present invention is preferably carried out in such a way that during the threading process of changing the warp, the fabric pulling device and/or the warp beam driving device are sometimes operated in a reverse operation mode. This means that the fabric pulling device sometimes does not operate in a forward running mode in which the knitted fabric is pulled from the knitting area at this time. In the reverse operation of the fabric pulling device, the knitted fabric is supplied to the knitting area from the fabric pulling direction. This makes it easy for the connecting area of the old warp yarn and the replacement warp yarn to pass through the eyelet of the eye needle. Similarly, the warp beam can sometimes be operated in a reverse mode, so that the replacement warp yarn is pulled toward the warp beam.

The method of the present invention is preferably designed in such a way that the fabric pulling device and/or the warp beam driving device are operated alternately in forward and reverse operation at a frequency of at least 1 Hz. This makes it easy for the connection point of the old warp yarn and the replacement warp yarn to pass through the eye needle. This working mode is like this at this time, the connection point is shaken through the hole to a certain extent with reduced resistance, just like the working mode of an excited vibrating screen.

More particularly preferably, the method of the present invention is designed such that during the threading process of changing the warp, the guide bar is displaced along the longitudinal axis of the guide bar at a frequency of at least 1 Hz. The interconnected warp yarns are thus excited, and their connection points can easily pass through the eye needles.

Advantageously, in an embodiment of the method of the invention, the guide bar is displaced along its longitudinal axis by less than one stitch length. The amplitude of the resulting vibration of the guide bar is therefore limited to a relatively short displacement length. This is especially meaningful when only one guide bar of the warp knitting machine is vibrated, but not in other cases, because it will not collide with adjacent warp yarns.

According to a possible variant, the method of the present invention can be designed such that during the threading process of the replacement warp, the yarn tension and/or appearance image of the connection point between the old warp and the replacement warp is monitored, and the standard deviation is determined At this time, the fabric pulling and/or the warp beam drive device is operated at a frequency of at least 1 Hz and/or the yarn guide bar is displaced along its longitudinal axis at a frequency of at least 1 Hz. The standard deviation is the deviation from one or more expected warp yarn parameters. According to the present invention, the expected warp yarn parameter may be the thickness of the connection point. Therefore, for example, the thickening or thinning of the connection point can be regarded as the standard deviation.

According to the invention, this connection point can also be monitored in such a way that whether or not yarn splicing occurs. The standard deviation can also be unexpectedly low yarn tension or increased yarn tension. It is best to measure the yarn tension separately on each yarn pair consisting of the old warp yarn and the replacement warp yarn. According to the present invention, other standard deviations can also be monitored.

The present invention can provide that the old warp yarn is connected to the replacement warp yarn along the yarn path between the eye needle and the warp beam. By pulling the knitted fabric, the connection point between the old warp yarn and the replacement warp yarn is then pulled through the eye of the eye needle. The yarn path depicts the path of the old warp yarn and the replacement warp yarn. The yarn path extends from the warp beam to the eye needle.

Preferably, before the knitted fabric is drawn, in order to pull the replacement warp yarn through the eyelet of the eye needle, the knitting needle of the warp knitting machine unloops all the loops. The knitting needles of the warp knitting machine can be compound needles, latch needles, pogo needles or other types of knitting needles, so they are in a yarn-free state before performing the method of the present invention. Therefore, the connection point does not have to be pulled through the hook of the knitting needle when performing the method of the present invention, which may introduce additional potential for error.

Particularly preferably, the knitting needle bar of the warp knitting machine is placed in a prescribed position before drawing the knitted fabric, and the knitting needle bar is maintained at the prescribed position during the drawing of the knitted fabric. According to the present invention, the predetermined position can be occupied by the knitting needle bar when the knitting needle is unlooped.

According to the present invention, the knitting needle bar may be a knitting needle-bearing bar of a warp knitting machine. The knitting needle does not capture the warp because the position of the knitting needle bar remains unchanged during the threading process. Therefore, the knitting needles also remain yarn-free during threading. According to the present invention, the predetermined position may be a loop-off position of the knitting needle bar. The loop-off position is a position where the knitting needle bar is in this position during the knitting process when the knitting needle is unlooped.

Advantageously, the warp threads are connected to each other by ultrasonic welding. At this time, the old warp yarn and the replacement warp yarn are excited by vibration in the ultrasonic range. Because of the internal friction that occurs at this time, the warp yarns become hot and can be welded to each other. As has been proven, ultrasonic welding is well suited for quickly joining warp yarns made of thermoplastic materials. The connection points that appear are not always uniform and may occasionally have reduced resistance. As has been proven, the probability of error when passing through the eye of the needle at such a connection point can be significantly reduced by means of the method of the present invention.

During the threading process of changing the warp yarns, the yarn speed of the warp yarns is preferably at least sometimes limited to a maximum of 1 mm/sec. According to the invention, this can be done in such a way that the fabric pulling device and/or the warp beam drive device runs at a suitable speed. According to the present invention, it is possible that when the connection point of the old warp yarn and the replacement warp yarn passes through the eyelet of the eye needle, the yarn speed of the warp yarn is at least or exactly limited to a maximum of 1 mm/sec. According to the present invention, the corresponding time can be determined based on machine visual monitoring of the warp yarn. However, according to the present invention, this moment can also be determined in other ways. For example, the time can be calculated based on the yarn speed and the distance between the connection point where the warp yarn is connected and the eyelet of the eye needle.

The present invention also relates to a warp knitting machine with a yarn threading function after the warp beam is replaced, including a fabric pulling device, a warp beam, a warp beam driving device connected with the warp beam, and a control device, wherein the control device is set up to perform The following steps: accept the threading instruction; after receiving the threading instruction, control the fabric pulling device to thread the yarn, so that the fabric pulling device pulls the knitted fabric by means of the fabric pulling device, so that the warp connected to the knitted fabric is threaded ; And in the process of controlling the fabric pulling device for threading, the warp beam driving device is controlled so that the warp beam is placed in rotation and actively releases the replacement warp yarn wound on the warp beam. The warp may be a replacement warp, but alternatively it may be an old warp as described in the introduction.

According to the present invention, the control device can be a machine computer, a microcontroller, a computer that is arranged away from the warp knitting machine and connected to it via a network, or other types of data processing devices.

It is also feasible according to the present invention that the warp knitting machine has a warp yarn connecting device. The warp yarn connecting device is a device suitable for connecting the warp yarns to each other. Here, according to the present invention, it can be a knotting device, an ultrasonic welding device or other types of warp yarn connecting devices.

The control device is preferably set up to synchronously control the warp beam driving device and the fabric pulling device, so that the warp yarn from the knitting area of the warp knitting machine is caused by pulling the knitted fabric with the fabric crimping device. It is consistent with the supply speed of the replacement warp yarn temporarily provided by the warp beam released on the warp beam.

Preferably, the control device is set up to control the fabric pulling device and/or the beam driving device, that is, the fabric pulling device and/or the beam during the process of controlling the fabric pulling device to thread the yarn. The driving device is operated in forward and reverse operation alternately at a frequency of at least 1 Hz. This can be said to allow the warp yarn connection point to sway through the eye needle of the warp knitting machine.

It is particularly preferable that the warp knitting machine has a servo motor for displacing the guide bar of the warp knitting machine along the longitudinal axis of the guide bar, wherein the control device is set up for controlling the process of the fabric drawing device The servo motor is controlled in such a way that the yarn guide bar is displaced along the longitudinal axis of the yarn guide bar at a frequency of at least 1 Hz. The eye needles of the warp knitting machine are preferably fixed on the guide bar. Through the movement of the guide bar, the connecting point of the warp yarn can easily pass through the eyelet of the eye needle.

It is also advantageous that the control device is set up to receive monitoring signals related to the yarn tension and/or appearance image of the connection point between the old warp yarn and the replacement warp yarn during the threading process of the replacement warp yarn, and to promote the fabric when the standard deviation is determined. The drawing and/or warp beam drive device operates at a frequency of at least 1 Hz and/or the guide bar is displaced along its longitudinal axis at a frequency of at least 1 Hz. According to the invention, the warp knitting machine may have at least one yarn tension sensor for determining the yarn tension. According to the present invention, the warp knitting machine may also have a camera for monitoring the appearance of the connection point.

FIG. 1 shows a schematic diagram of the warp knitting machine 1 of the present invention before the warp beam 2 of the warp knitting machine 1 is replaced. The warp knitting machine 1 has a fabric drawing device 3, a plurality of yarn guide bars 4, a knitting needle bar 5, and a warp yarn connecting device 6. The warp yarn connecting device is provided for ultrasonic welding of the warp yarn 7, of which only one is shown as an example Warp 7. A plurality of eye needles 8 are fixed on the yarn guide bar 4. The warp yarn 7 is guided through the eyelet 9 of the eye needle 8.

The warp beam 2 is idling and should now be replaced. For this purpose, first all the warp yarns 7 are unlooped by the knitting needles 10 fixed on the knitting needle bar 5. The knitting needle bar 5 is now placed in the loop-off position and then held in the loop-off position. Next, the warp yarn 7 is cut.

FIG. 2 shows a schematic diagram of the warp knitting machine 1 of the present invention after the warp beam 2 has been replaced. The ends of the warp yarns originally located in the warp knitting machine 1 now form the old warp yarns 11, and the warp yarns exiting from the newly exchanged warp beams 2 are referred to as replacement warp yarns 12. An old warp yarn 11 and a replacement warp yarn 12 are respectively shown as examples. The warp yarn connecting device 6 is inserted in the yarn path between the yarn guide bar 4 and the warp beam 2. The old warp yarn 11 and the replacement warp yarn 12 are placed in the warp yarn connecting device 6 and are thereby connected to each other.

Fig. 3 shows a detailed schematic diagram of the eye needle 8 of the warp knitting machine of the present invention during threading. According to the method of the present invention, the knitted fabric produced by the warp knitting machine is drawn from the knitting area of the warp knitting machine by a fabric pulling device. At the same time, the warp beam drive device of the warp knitting machine makes the warp beam in rotation. The old warp yarn 11 and the replacement warp yarn 12 are connected to each other in the area of the ultrasonic welding connection point 13. By pulling the knitted fabric, the connection point 13 is pulled through the eyelet 9 of the eye needle 8. During this period, the warp beams take the initiative to supplement and supply the replacement warp yarn 12. This helps the connection point 13 to pass through the eyelet 9.

Figure 4 shows a schematic view of the warp knitting machine 1 during threading. The warp yarn connecting device 6 is now no longer in the yarn path. Likewise, the knitting needle 10 does not hold the warp yarn. In order to allow the connection point 13 to reliably pass through the eyelet 9 of the eye needle 8, the fabric pulling device 3 and the warp beam driving device sometimes operate in a reverse operation mode. This happens precisely when the not-shown control device of the warp knitting machine 1 determines the standard deviation related to the warp yarn tension. To this end, the warp knitting machine 1 is equipped with a yarn tension sensor not shown. The reverse operation is also started when the control device determines an impermissible thickening or thinning of the connection point 13. To this end, the warp knitting machine 1 is equipped with a camera not shown in order to grasp the connection point 13 visually.

1: warp knitting machine 2: warp beam 3: Fabric pulling device 4: yarn guide bar 5: Knitting needle comb 6: Warp connection device 7: Warp 8: Eye needle 9: Eyelet 10: Knitting needles 11: Old warp 12: Change the warp 13: Connection point

A preferred embodiment of the present invention is shown in the figure, where: [Fig. 1] A schematic diagram showing the warp knitting machine of the present invention before the warp beam of the warp knitting machine is replaced, [Fig. 2] A schematic diagram showing the warp knitting machine of the present invention after the warp beam is replaced, [Fig. 3] A detailed schematic diagram showing the eye needle of the warp knitting machine of the present invention when threading, and [Fig. 4] A schematic diagram showing the warp knitting machine at the time of threading.

Claims (17)

A method for threading yarn after the warp beam is changed in a warp knitting machine (1), the method has the following steps: -Connect the old warp yarn (11) with the replacement warp yarn (12), which passes through the eye needle (8) fixed on the guide bar (4) of the warp knitting machine (1) The perforations (9) form the knitted fabric that is drawn into the fabric pulling device (3) of the warp knitting machine (1), and the replacement warp yarn belongs to the warp beam newly replaced in the warp knitting machine (1) (2), -Thread the replacement warp yarn (12) through the fabric pulling device (3) to pull the knitted fabric, so that the old warp yarn (11) pulls the replacement warp yarn (12) through the The eyelet (9) of the eye needle (8), -During the threading process of the replacement warp yarn (12), the warp beam (2) is rotated by the warp beam driving device of the warp knitting machine (1), so that the replacement warp yarn (12) passes through The warp beam (2) is actively released. The method according to claim 1, wherein the drawing of the knitted fabric is performed synchronously with the operation of the warp beam driving device, so that the old warp yarns (11) caused by the drawing of the knitted fabric The threading speed of the eyelet (9) passing through the eye needle (8) is consistent with the yarn feeding speed of the warp beam (2) releasing the replacement warp yarn (12). The method according to claim 1 or 2, wherein during the threading process of the replacement warp yarn (12), the fabric pulling device (3) and/or the warp beam driving device sometimes retreat Run mode operation. The method according to claim 3, wherein the fabric pulling device (3) and/or the warp beam driving device are operated alternately in forward operation and reverse operation at a frequency of at least 1 Hz. The method according to any one of claims 1 to 4, wherein during the threading process of the replacement warp yarn (12), the yarn guide bar (4) runs along the The longitudinal axis of the guide bar (4) is shifted. The method according to claim 5, wherein the yarn guide bar (4) is shifted by less than one stitch length along its longitudinal axis. The method according to any one of claims 1 to 6, wherein in the threading process of the replacement warp yarn (12), -Monitoring the yarn tension and/or appearance image of the connection point between the old warp yarn (11) and the replacement warp yarn (12), and -When the standard deviation is determined, the fabric is drawn and/or the warp beam drive device is operated at a frequency of at least 1 Hz and/or the yarn guide bar (4) is shifted along its longitudinal axis at a frequency of at least 1 Hz yuan. The method according to any one of claims 1 to 7, wherein the old warp yarn (11) and the yarn path between the eye needle (8) and the warp beam (2) are Replace the warp yarn (12) connected. The method according to any one of claims 1 to 8, wherein before the knitted fabric is pulled, in order to pull the replacement warp yarn (12) through the eyelet (9), the warp knitting machine (1) The knitting needle (10) of) unwinds all the stitches. The method according to any one of claims 1 to 9, wherein the knitting needle bar (5) of the warp knitting machine (1) is placed in a prescribed position before drawing the knitted fabric and is in the drawing station The knitted fabric is held at the prescribed position during the period. The method according to any one of claims 1 to 10, wherein the warp yarns are connected to each other by ultrasonic welding. The method according to any one of claims 1 to 11, wherein during the threading process of the replacement warp yarn (12), the yarn speed of the knitting position is at least sometimes limited to a maximum of 1 mm/sec. A warp knitting machine (1) with a yarn threading function after the warp beam is replaced. The warp knitting machine includes a fabric pulling device (3), a warp beam (2), and a warp beam connected to the warp beam (2) The drive device and the control device, wherein the control device is set up to perform the following steps: -Accept threading instructions; -After receiving the threading instruction, control the fabric pulling device (3) for threading, so that the fabric pulling device (3) pulls the knitted fabric by means of the fabric pulling device (3). This warp yarn connected to the knitted fabric is threaded in; and -Control the warp beam drive device during the process of controlling the fabric pulling device (3) for threading, so that the warp beam (2) rotates and actively releases the warp beam (2) that is wound onto the warp beam (2) ) On the replacement warp (12). The warp knitting machine (1) according to claim 13, wherein the control device is set up to synchronously control the warp beam driving device and the fabric pulling device (3) so that the warp knitting machine (1) The warp yarn in the knitting zone is wound on the warp due to the threading speed caused by the fabric pulling device (3) pulling the knitted fabric and the warp beam (2) being released. The yarn supply speed of the replacement warp yarn (12) on the shaft (2) is the same. The warp knitting machine (1) according to claim 13 or 14, wherein the control device is set up to control the fabric pulling device (3) in the process of controlling the fabric pulling device (3) for threading (3) and/or the warp beam driving device, so that the fabric pulling device (3) and/or the warp beam driving device are operated in a forward and reverse operation alternately at a frequency of at least 1 Hz. The warp knitting machine (1) according to any one of claims 13 to 15, wherein the warp knitting machine (1) has a guide bar (4) for making the warp knitting machine (1) The longitudinal axis of the yarn guide bar (4) is shifted by a servo motor, wherein the control device is set up to control the servo motor in the process of controlling the fabric pulling device (3), that is, The yarn guide bar (4) is displaced along the longitudinal axis of the yarn guide bar (4) at a frequency of at least 1 Hz. The warp knitting machine (1) according to any one of claims 13 to 16, wherein the control device is set up to be used in the threading process of the replacement warp yarn (12) -Receive monitoring signals related to the yarn tension and/or appearance image of the connection point between the old warp yarn (11) and the replacement warp yarn (12), and -When the standard deviation is determined, the fabric is drawn and/or the warp beam drive device is operated at a frequency of at least 1 Hz and/or the yarn guide bar (4) is shifted along its longitudinal axis at a frequency of at least 1 Hz yuan.

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