Method for producing a material tube

Abstract

The invention relates to a method for producing a material tube from at least one material web, in which - a first material web is unwound from a first material web roll, - a second material web roll having a second material web is provided, - the leading end of the second material web is fastened to the first material web in a fastening region by a fastening device, - the first and / or the second material web is provided with weakening lines by a perforation or cutting device arranged downstream of the fastening device, each of which weakening lines assumes the same distance from one another, - wherein the fastening region is arranged in a region of the first material web that is located between two weakening lines that are to be subsequently introduced or are subsequently introduced.

Description

[0001] Process for producing a material hose

[0002] The invention relates to a method for producing a material hose according to claim 1.

[0003] To produce bags or sacks, it is necessary to create a tube from a first flat material web. During the tube formation process, its side edges are folded towards the center line of the web so that the side edges overlap. The side edges are glued together along this overlap to create a continuous tube. If, however, the tube is to be divided into tube pieces in order to make a sack or bag from each of these, the tube can be cut using a cutting device. However, if the upper and lower layers of the tube are not to be separated at overlapping points, the material web must be perforated using a perforating device before the tube is formed.After the tube is formed, the tube can then be pulled in opposite directions on both sides of this perforation, causing the tube to tear along the perforation. A cut or perforation can be collectively referred to as a line of weakness in the context of the present disclosure.

[0004] After a certain time, the first material web unwound from a first material web roll will reach its end. This means that the material web roll is almost completely unwound. For further production of the hose, a second material web roll containing a second material web is usually provided.

[0005] The leading end of the second material web is then secured to the first material web in a fastening area by a fastening device. The fastening device is usually located upstream of the perforating or cutting device.

[0006] For this purpose, it is usually necessary to slow down the transport speed of the first material web and the second material web, sometimes to a standstill.

[0007] The object of the present invention is therefore to propose a method in which the fastening of the second material web to the first material web can take place at a higher transport speed of the first material web without this giving rise to other problems.

[0008] According to the invention, this object is achieved by all features of claim 1. Possible embodiments of the invention are specified in the dependent claims.

[0009] According to the present invention it is provided that

[0010] • a first material web is unwound from a first material web roll,

[0011] • a second material web roll with a second material web is provided,

[0012] • the leading end of the second material web is fastened to the first material web in a fastening area by a fastening device,

[0013] • the first and / or the second material web is provided with weakening lines by a perforation or cutting device arranged downstream of the fastening device, which weakening lines are in particular each at the same distance from one another,

[0014] • wherein the fastening area is arranged in an area of ​​the first material web which lies between two subsequently introduced lines of weakness.

[0015] The second roll of material web is preferably in contact with a drive device that sets the second roll of material web in rotation. The leading end of the second material web is then guided by a guide device into the area of ​​the first material web. The first material web and / or the second material web is provided with an adhesive element, for example a double-sided adhesive film piece or an applied adhesive. The leading end of the second material web and the first material web are then pressed together so that they adhere to one another. The area to which the webs adhere to one another is thus considered the fastening area.

[0016] For continuous hose production, it is necessary that the perforation or cutting device is arranged downstream of the fastening device, because otherwise it would not be possible to feed the second material web to the perforation or cutting device. The perforation or cutting device introduces one or more weakening lines running in the transverse direction into the first material web. Parts of the weakening lines can also run at least partially in the longitudinal direction. However, it is important that at least one path along a weakening line extends across the entire width of the material web. Two directly consecutive paths of the weakening line that delimit a subsequent hose section are, in particular, the same distance from one another in the transport direction in order to enable a uniform hose section length.

[0017] According to the invention, it is further provided that the fastening area lies between two consecutive weakening lines, which, as already described, are introduced subsequently. This means that the weakening lines are free of parts of the fastening area or do not overlap with them.

[0018] This ensures that the introduction of weakening lines is not disrupted by the fastening area. Also, the tools of the perforating or cutting device cannot become contaminated by the adhesive element. Furthermore, when the hose is later cut into pieces, it is avoided that the hose tears along the fastening area instead of the weakening line. Typically, tools engage the hose on both sides of the weakening line, with a relative movement of the two tools, for example due to different circumferential speeds of roller pairs, tearing a piece of the hose off. However, if one tool engages exclusively on the first material web and the second tool engages exclusively on the second material web, tearing may occur along the fastening area.

[0019] It is advantageous if the first material web is severed upstream with a separating cut, so that only a short flag of the first material web remains behind the fastening section. This short flag is preferably dimensioned so that it lies entirely within the area between two subsequently introduced or introduced weakening lines. However, if the length of the subsequent hose sections is short, it can be provided that this flag also extends over the subsequent weakening line (and only over the subsequent weakening line), with the end of the flag again lying between two weakening lines.

[0020] In a further development of the method according to the invention, it is provided that the fastening area is located at a fixed distance from the weakening lines located at the front in the transport direction of the material web. This means that, in order to position the fastening area between two weakening lines according to the invention, the fastening area is provided at a fixed distance from the respective front weakening line, wherein this distance is determined independently of the distance between two adjacent weakening lines. This ensures that the fastening area does not overlap with the front of the two consecutive weakening lines. Preferably, the distance is selected such that it is smaller than the smallest possible distance between two consecutive weakening lines. This smallest possible distance is generally determined by the geometric properties of the cutting or perforating tool.

[0021] It is advantageous if, before the second material web is attached to the first material web, the leading end of the second material web or a marking on the second material web is brought into a defined angular position relative to a vertical plane that runs through the axis of rotation of the material web roll containing the material web. Two options are considered here: On the one hand, a material web can be provided which bears imprints, for example in the form of advertising prints or customer information, so that it is necessary to attach the second material web to the first material web in register. A register mark belonging to this imprint or a component of the print itself can represent a marking. If such a marking is not present, the leading end of the second material web must be positioned, which represents the second positioning option.Positioning can be performed manually or by a sensor that already assumes a fixed position. For manual positioning, a positioning aid, such as a dipstick, can be provided. Positioning requires rotating the second roll of material web, which can be done using a roller drive or manually. The roll is rotated by the drive until the sensor or the operator causes the drive to stop because the angular position has been reached. Appropriate positioning simplifies the inventive arrangement of the fastening area.

[0022] The diameter of the second material web roll is determined before the second material web is attached to the first material web. The diameter determination can be performed manually or automatically. Advantageously, with precise knowledge of the diameter of the material web roll, a rotational speed for the material web roll can be set. This results in a web speed for the leading end of the further material web that corresponds to the transport speed of the first material web, thus easily positioning the attachment area at the desired location.

[0023] In a preferred embodiment for determining the diameter, a rolling element with a known circumference is placed against the circumferential surface of a second roll of material web, wherein the total angle of rotation of the rolling element and the total angle of rotation of the shaft supporting the second roll of material web are determined between a start time and an end time, the roll of material web being rotationally driven. The rolling element, which has a known circumference, is thus rolled over the circumferential surface of the roll of material web, wherein the total angle of rotation of the rolling element is measured. In particular, it is provided that the rolling element can be driven by a drive motor and serves to drive the roll of material web. In this case, the angle of rotation can also be determined in or on the motor using a known angle sensor. The angle of rotation of the shaft supporting the second roll of material web is also determined.For this purpose, the shaft can be provided with at least one detectable element, such as a magnet, which can be detected by a magnetic sensor. At any starting point, the material web roll is set in rotation and stopped again at an end point. The preferred end point is the point in time at which the shaft supporting the second material web roll has been rotated exactly 360 degrees, in order to maintain the previous positioning of the web start or a marking, if necessary. The diameter of the material web roll is then calculated from the total angle of rotation of the rolling element, its diameter, and the total angle of rotation of the shaft.In a further advantageous step, it is provided that the length of the web path between the leading end or the marking of the second material web and the fastening device is calculated from the defined angular position of the leading end of the second material web or the marking on the second material web and the circumference of the second material web. Preferably, the fastening device comprises a pressure roller over which at least the first material web runs in a period of time before the second material web is fastened to the first material web. With this pressure roller, the first material web can be guided towards the second material web and brought into contact, such that the second material web is connected to the first material web in the fastening section. In this case, the contact point of the pressure roller is to be calculated, which essentially depends on the outer circumference of the second material web roll.In this case, the web path is a curved section along the outer circumference of the material web roll. However, it is also possible to guide the leading end of the second material web along a path to the fastening device using guide means. This guide path also depends on the outer circumference of the second material web roll. Using this calculation, it is therefore possible to provide an acceleration path for the second material web roll.

[0024] In a further step, it is preferred that an acceleration is calculated from the web path and the web speed of the first material web, with which acceleration the second material web roll must be accelerated, so that the leading end of the second material web or the marking on the second material web at the location of the fastening device adopts substantially the same transport speed as the first material web. In particular, it is provided that the leading end of the second material web has reached the transport speed of the first material web, wherein the angle of rotation of the second material web roll is preferably less than 360 degrees. This achieves the shortest possible acceleration path and an improved arrangement of the fastening region on the first material web.It is further preferred if a relative starting time for the acceleration of the second material web is calculated depending on the web speed of the first material web, the length of the web path of the first material web between the fastening device, and the time at which a weakening line is introduced into the first material web. This provides recurring times at which the second material web roll must be set in motion so that the fastening section assumes the desired position on the first material web roll.

[0025] In a final, advantageous step, a start signal is provided to start the second material web roll, with the acceleration of the second material web roll beginning at the next relative start time after the time at which the start signal is given. This start signal can be given by an operator. However, it is also advantageous if the remaining length of the first material web on and / or the diameter of the first material web roll is regularly determined, and the start signal is given when a threshold value is undershot. This can preferably be done by a computing and control unit.

[0026] The above-mentioned object is also achieved by a device for carrying out the method described above, wherein the device according to the invention is equipped with at least:

[0027] • a first unwinding station in which a first material web can be unwound from a first material web roll,

[0028] • a second unwinding station in which a second material web roll with a second material web can be provided,

[0029] • a fastening device with which the leading end of the second material web can be fastened to the first material web in a fastening area,

[0030] • a perforation or cutting device arranged downstream of the fastening device, with which the first and / or the second material web can be provided with weakening lines, which in particular each occupy an equal distance from one another, wherein the fastening region can be arranged in a region of the first material web which lies between two subsequently introduced weakening lines.

[0031] The device according to the invention achieves the same advantages as have already been described in connection with the method according to the invention.

[0032] Further advantages, features, and details of the invention will become apparent from the following description, in which various exemplary embodiments are explained in detail with reference to the figures. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination of mentioned features. Within the scope of the entire disclosure, features and details described in connection with the method according to the invention naturally also apply in connection with the device according to the invention, and vice versa, so that with regard to the disclosure, reference is always made to the individual aspects of the invention. The individual figures show:

[0033] Fig. 1 Side view of an unwinding device

[0034] Fig. 2 Side view of an unwinding device during the determination of the circumference of the second material web rolls

[0035] Fig. 3 Side view of an unwinding device during the attachment of the second material web to the first material web

[0036] Figure 1 shows an unwinding device 100 in which a first material web roll 101 is rotatably mounted in a secondary storage location. A first material web 102 is unwound from this first material web roll 101 and guided out of the unwinding device along a transport or web path, indicated by the arrow x. The material web is then fed to a tube forming station in which - as already described in more detail above - a material tube is formed. The material web roll 101 was previously transferred from a main storage location to the secondary storage location, since a majority of the first material web 102 has already been unwound and a second material web is to be connected to the first material web 102 in order to ensure a continuous supply of a material web.

[0037] The first material web 102 is guided in the unwinding device over various deflection rollers 103, 104, with the deflection roller 103 being part of a fastening device, which is not explained in detail. The fastening station can also be designed differently; a deflection roller is not a mandatory component.

[0038] Further along the web path, the material web 102 passes through a cutting or perforating station, in which the material web is provided with at least one cut or at least one perforation at regular intervals. The following explanation of the cutting or perforating station represents only one embodiment; other embodiments may be provided instead. The material web 102 is guided over a counter-roller 110. The perforation and / or cutting roller 111 carries a cutting or perforating blade 112. Due to the rotation of the roller 111, the cutting and / or perforating blade 112 comes into contact with the material web at regular intervals, so that it is provided with cuts and / or perforations at regular intervals.In order to be able to change the spacing of the cuts and / or perforations, it can be provided that the perforation and / or cutting rollers rotate at a different speed during the periods in which their blade 112 is not in contact with the material web, in order to lengthen or shorten the rotation time. Additionally or alternatively, the distance of the roller 111 from the counter-roller 110 can be changed, wherein the blade 112 is replaced by one whose cutting edge is at a greater or smaller distance from the rotational axis of the roller 111 than the replaced blade. In this case, it is possible to always operate the cutting edge of the blade 112 at a peripheral speed that corresponds to the transport speed of the material web.Based on the rotational speed of the cutting edge of the knife, the length of the web path and the transport speed of the material web 102, it can be calculated by means of a computing and control device (not shown) at which times the points of the material web that will later be provided with at least one cut and / or perforation pass the deflection roller 103.

[0039] Figure 1 shows that the second material web roll 121, on which a second material web 122 is wound, has already been inserted into the main storage location. In one method step, the second material web roll 121 is positioned such that the leading end of the second material web 122, also referred to as the web start 123, forms a known angle α to the plane 124, wherein the plane runs through the axis of rotation of the material web roll 121 and is preferably oriented vertically, wherein "vertical" refers to the surface on which the unwinding device is set up. Instead of the web start 123, a marking (not shown) can also be positioned on the second material web relative to the plane 124. Such a marking can, for example, be part of an imprint or a register mark.

[0040] Figure 2 shows a similar situation to Figure 1, wherein essentially the same elements are visible, which for the sake of clarity are not provided with reference numerals again. An additional component is a drive pulley 125 of a drive device, wherein the drive pulley acts on the outer circumference of the second material web roll 121. To determine the diameter or circumference, the second material web roll is set in rotation via the drive pulley 125 and rotated through a specified angle of rotation, preferably 360 degrees, which is shown by the arrow R. The size of the angle of rotation is queried via the shaft 126, which carries the second material web roll 121. For this purpose, the shaft carries marking elements, for example magnets or prints or stickers, which are detected by suitable sensors, for example a magnetic sensor or an optical sensor.The circumference of the second material web roll 121 is calculated from the size of the angle of rotation, the total angle of rotation of the drive pulley during the rotational movement of the second material web roll and the circumference of the drive pulley, which is known.

[0041] From this circumferential value, the angular position of the contact line 130 of the deflection roller 103, when it is pivoted along the arrow S towards the second material web roll 121, can also be calculated relative to the plane 124 and thus relative to the angular position of the web start 123.

[0042] The difference between the aforementioned angular positions and the circumference of the second material web roll 121 is used to calculate the circumferential arc that the beginning of the web must travel to come into contact with the first material web. This circumferential arc simultaneously represents the acceleration path within which the second material web roll must be accelerated, particularly from a standstill, so that the beginning of the web assumes the transport speed of the first material web upon contact with the first material web. The circumferential arc can be less than 360 degrees, but it can also assume an angle greater than 360 degrees.

[0043] From the duration of this acceleration, the times at which the points on the first material web that will later be provided with a cut and / or perforation, and an offset provided for these cuts and / or perforations, it is now possible, using mathematical relationships known to those skilled in the art, to calculate starting times at which the second material web roll must be set in rotation so that the web start of the first material web roll meets the first material web at a previously determined distance from a later cut and / or perforation. In order to fasten the second material web to the first material web, the second material web is provided near the web start with a connecting element 131, for example with a double-sided adhesive label. The actual fastening process is now shown in Figure 3.In particular, if the first material web roll has fallen below a specified minimum diameter and / or a machine operator has given a start signal, the second material web roll is set in motion at the next available start time and accelerated according to the previously calculated, necessary acceleration. The deflection roller with the first material web is pivoted toward the second material web roll, so that contact is established between the first material web and the second material web roll. Subsequently, upstream of the deflection roller 103, the material web 102 is severed by a cutting device (not shown) at a cutting point located upstream of the fastening area in which the second material web is fastened to the first material web.After the second material web has been secured to the first material web by the connecting element 131, the material web is unwound from the second material web roll and subsequently provided with perforations and / or cuts by the cutting and / or perforating knife. Due to the previously made settings and the selected start time, it is impossible for the cutting and / or perforating knife 112 to strike the fastening area and thus, in particular, the connecting element 131.

[0044]

Claims

Patent claims Method for producing a material hose from at least one material web, in which • a first material web is unwound from a first material web roll, • a second material web roll with a second material web is provided, • the leading end of the second material web is fastened to the first material web in a fastening area by a fastening device, • the first and / or the second material web is provided with weakening lines by a perforation or cutting device arranged downstream of the fastening device, which weakening lines are in particular each at the same distance from one another, • wherein the fastening region is arranged in a region of the first material web that lies between two subsequently introduced or introduced weakening lines. Method according to claim 1, characterized in that the fastening region is located at a fixed distance from the weakening lines located at the front in the transport direction of the material web. Method according to one of the preceding claims, characterized in that, before the second material web is attached to the first material web, the leading end of the second material web or a marking on the second material web is brought into a predetermined angular position relative to a vertical plane passing through the rotational axis of the material web roll comprising the material web. Method according to one of the preceding claims, characterized in that, before the second material web is attached to the first material web, the diameter of the second material web roll is determined.Method according to the preceding claim, characterized in that, in order to determine the diameter, a rolling element with a known circumference is placed on the circumferential surface of the second material web roll, wherein the total angle of rotation of the rolling element and the total angle of rotation of the shaft supporting the second material web roll are determined between a starting time and an end time, the material web roll being driven in rotation. Method according to one of the preceding claims, characterized in that, from the specified angular position of the leading end of the second material web or the marking on the second material web and the circumference of the second material web, the length of the web path between the leading end or the marking of the second material web and the fastening device is calculated. Method according to the preceding claim, characterized in that, from the web path and the web speed of the first material web, a...The acceleration is calculated with which the second material web roll must be accelerated such that the leading end of the second material web or the marking on the second material web at the location of the fastening device assumes essentially the same transport speed as the first material web. Method according to one of the preceding claims, characterized in that a relative starting time for the acceleration of the second material web is calculated as a function of the web speed of the first material web, the length of the web path of the first material web between the fastening device, and the time at which a weakening line is introduced into the first material web.Method according to the preceding claim, characterized in that a start signal is given to start the second material web roll, wherein the acceleration of the second material web roll begins at the next relative start time after the time at which the start signal is given. Device for carrying out a method according to one of claims 1 to 9. • a first unwinding station in which a first material web can be unwound from a first material web roll, • a second unwinding station in which a second material web roll with a second material web can be provided, • a fastening device with which the leading end of the second material web can be fastened to the first material web in a fastening area, • a perforation or cutting device arranged downstream of the fastening device, with which the first and / or the second material web can be provided with weakening lines, which in particular each have the same distance from each other, • wherein the fastening region can be arranged in a region of the first material web which lies between two subsequently introduced weakening lines.

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