EP0196688B1 - Knife cylinder for machining webs of material - Google Patents

Description

The proposed device relates to a knife cylinder for processing paper, plastic or metal foil, fabrics or the like. Existing web-like material with at least one for receiving and fastening one essentially parafie! to the axis of rotation of the knife cylinder arranged knife, also parallel to the axis of rotation of the knife cylinder on its circumference, incorporated into the knife cylinder and distributed over the length of each knife arranged pressure points for clamping the respective knife against the knife cylinder by means of several, over the length of each knife distributed arranged, the respective knife against the knife cylinder pressure medium cylinder and with a circulating with the knife cylinder, with pressure medium cylinders in connection channel system and connection for filling and draining the pressure medium and each knife at least one arranged between this knife and an associated pressure medium cylinder.

Knife cylinders of the type mentioned are used in machines to make incisions in sheet-like materials. These incisions can be made with knives that do not have a continuous cutting edge, so that a perforation is produced in this way. The knives can also have a continuous cutting edge, which makes it possible to cut sheets of a certain length from an endless path. The cutting lines are usually directed transversely to the running direction of the web to be processed, but they can also be arranged obliquely to the running direction of the web.

The knives required for this are usually inserted into a revolving knife cylinder in such a way that knives that have become blunt can be exchanged without the entire cylinder having to be removed from the respective processing machine, for example a form printing machine. At least one knife is attached to each knife cylinder. However, in order to achieve cuts which are at a shorter distance from one another than the diameter of the knife cylinder, a plurality of knives, for example six knives, can be distributed around the circumference of the knife cylinder.

So that the knives can be effective in the desired manner, they have to be set in relation to the web to be processed or a pressure cylinder interacting with the knife cylinder. To make this possible again, the knives can only be non-positively attached to the knife cylinders or within these cylinders. If the knives have become blunt in the course of their use, then they should be able to be exchanged for new knives. However, an exchange of the knife generally means that both the cutting device, in which the respective knife is installed, and a further machine, for example a form printing machine, possibly cooperating with the cutting device, must be stopped. Stopping the machine inevitably means a loss of production which is as large as the time in which the machine must be stopped. Efforts are therefore made to replace the knives with as little time as possible.

A device of the aforementioned type is known, for example, from EP-A 0 115 783, which is why this prior publication is used to supplement the present description of the present patent request and to explain the background of the present patent request.

In addition, a device for cross-perforating webs is known from US Pat. No. 2,682,306, in which each perforating knife is fastened to the perforating cylinder with the aid of a plurality of screws. To loosen and tighten these screws, a seemingly intolerable length of time is required, with the result that the knives cannot be changed quickly enough. Furthermore, to change the knives, each knife must be loosened individually and each new knife individually fastened to the rotating cylinder. As a result, the time required for changing the knives is also considerably extended.

In addition, DE-OS 2 021 061 describes a holder for the knife of a cross-cutting device, an inflatable hose being proposed for holding a knife in a corresponding rotating cylinder. However, the applicant believes that the construction which provides for the use of a hose is not suitable for fastening knives such as those of the present protection request, since either the respective knife cannot be tightened sufficiently, or if a very firm hose is used a lot of energy and pressure must inevitably be used to expand this firmer hose. In this way, relatively little energy or pressure is available for clamping the knife. In addition, due to the fact that it is pressurized from the inside, an elastic hose would be pressed against the machine parts surrounding it to such an extent that it would yield even slightly due to the high forces acting on it. The jacket of the hose would flow, for example, and attempt to flow into the joints of the machine parts surrounding it. This would be the beginning for the jacket of the hose to wear out quickly at the respective point. The consequence would be a further flow of the hose, since the cross section of its jacket would be weakened. In this way, the hose as a whole would break after a very short period of use and would thus be unsuitable for the purpose mentioned.

It is therefore the task, while avoiding the disadvantages of previously known devices, to propose a knife cylinder in which the knives can be changed easily, conveniently and quickly and which can be manufactured more simply and inexpensively using simpler parts than previously known devices of this type.

This object is achieved in that the pressure medium cylinders assigned to each groove are arranged both within the groove and essentially in the circumferential direction of the knife cylinder, the pressure medium cylinders are bellows cylinders and the bellows cylinders are made of metal. These bellows cylinders can be so-called metal bellows, membrane bellows or even miniature bellows. In addition, it is proposed that the pressure medium cylinders assigned to the respective knife are attached to the insert assigned to this knife. It is possible for the pressure medium cylinders assigned to a knife to be fastened to the side wall of the respective groove facing away from the respective knife of the two side walls of the respective groove which are machined into the knife cylinder and are arranged essentially radially to the knife cylinder. This can be achieved with or without a pressure bar, which is inserted between the side wall facing away from the respective knife of the two side walls incorporated into the knife cylinder and arranged essentially radially to the knife cylinder and the pressure medium cylinder assigned to the respective knife.

Furthermore, it is possible for at least part of the channel system for the pressure medium to be incorporated into the insert or the pressure bar likewise located on the knife. The pressure bar has an essentially trapezoidal cross section, the radially inner side of the trapezoid corresponding to the cross section of the groove and the radially outer side of the trapezoid corresponding to the circumference of the knife cylinder.

The proposed solution makes it possible for the entire knife cylinder to be manufactured more simply and therefore more cost-effectively than, for example, that of EP-A 0 115 783. In particular, the manufacture of the knife cylinder is simplified in that only axially parallel grooves need to be machined into it . In addition, transverse grooves, for example for lever transmission of the device according to EP-A 0 115 783, or transverse, offset and threaded bores are completely avoided. In addition, it is proposed that the technical and financial advantages of the so-called metal bellows known per se also be used for the special requirements which the clamping of cross-cutting or cross-perforating knives pose. In particular, it is possible to initially clamp the knife to be clamped with a relatively low pressure, i. H. preload with relatively low forces, align them sensitively with respect to the pressure cylinder by rotating the knife cylinder and the associated pressure cylinder and then clamp the knives forcefully for the operating process in such a way that they cannot slip against the knife cylinder or the pressure cylinder during the course of operation. In addition, it is possible to either clamp all the knives or only the desired knife or to replace the processing machine, such as a form printing machine, which is usually related to the cross-perforating or cross-cutting device when the downtime is short. In this way, there is little loss of production overall.

The proposed device will now be explained in more detail with reference to several exemplary embodiments schematically depicted in the attached figures, which do not limit the inventive concept. These exemplary embodiments can be modified in various ways without leaving the framework defined by the basic idea of the invention. In the present context, the figures do not show essential machine parts because of a clearer representation, since these parts are already sufficiently well known to the person skilled in the art.

• Fig. 1: Gesamtansicht der Schneid- oder Perforiereinrichtung, teilweise im Schnitt dargestellt
• Fig. 2: Schnittbildliche Darstellung des Messerzylinders eines ersten Ausführungsbeispieles
• Fig. 3: Schnitt III-III in den Figuren 2, 4, 5 und 6, gegenüber diesen Figuren in einem anderen Maßstab
• Fig. 4: Schnittbildliche Darstellung des Messerzylinders in einem zweiten Ausführungsbeispiel
• Fig. 5: Schnittbildliche Darstellung des Messerzylinders in einem dritten Ausführungsbeispiel
• Fig. 6: Schnittbildliche Darstellung des Messerzylinders in einem vierten Ausführungsbeispiel
• Fig. 7: Übersicht über eine zentrale Druckmittelversorgung für die Ausführungsbeispiele nach den Fig. 2 und 6
• Fig. 8: Übersicht über eine zentrale Druckmittelversorgung für die Ausführungsbeispiele nach den Fig. 4 und 5
• Fig. 9: Druckerzeuger für eine zentrale Druckmittelversorgung für die Einrichtungen nach den Fig. 7 und 8
• Fig. 10: Schnittbildliche Darstellung des Messerzylinders in einem fünften Ausführungsbeispiel

The individual figures mean:

• Fig. 1: Overall view of the cutting or perforating device, partially shown in section
• Fig. 2: sectional view of the knife cylinder of a first embodiment
• Fig. 3: Section III-III in Figures 2, 4, 5 and 6, compared to these figures on a different scale
• Fig. 4: Sectional representation of the knife cylinder in a second embodiment
• Fig. 5: sectional representation of the knife cylinder in a third embodiment
• Fig. 6: Sectional representation of the knife cylinder in a fourth embodiment
• 7: Overview of a central pressure medium supply for the exemplary embodiments according to FIGS. 2 and 6
• 8: Overview of a central pressure medium supply for the exemplary embodiments according to FIGS. 4 and 5
• 9: Pressure generator for a central pressure medium supply for the devices according to FIGS. 7 and 8
• 10: sectional representation of the knife cylinder in a fifth embodiment

A web 1 made of paper, plastic, metal, foil, fabric or the like runs past a printing cylinder 2 and partially wraps around it. At the same time, the web 1 passes through a nip which is formed by the pressure cylinder 2 and the knife cylinder 3. The pressure cylinder 2 and the knife cylinder 3 are rotatably supported in a machine frame 5 with the aid of corresponding bearings 4. At least one of the two cylinders 2 or 3 is driven, but it is also possible for the two cylinders to be connected to one another by gearwheels, toothed belts or the like in such a way that they rotate in a fixed phase relative to one another can. In this case, it is only necessary to drive one of the two cylinders, since the other is also driven by the synchronizing device consisting of gear wheels, toothed belts or the like.

Knife positions 6, 7, 8, 9, 10 and 11 are provided on the knife cylinder 3. The knives located at positions 6 to 11 extend essentially in the direction of the geometric axis of the knife cylinder 3 and are provided in the knife cylinder 3 parallel or slightly inclined to this axis. The associated knives can have a continuous cutting edge or a cutting edge interrupted by transverse grooves. In the case in which the knives have a continuous cutting edge, the web 1 is cut transversely into individual sheets as it passes through the nip formed by the cylinders 2 and 3.

If, on the other hand, the knives are divided into several individual cutting edges by grooves running transversely to their cutting edge, then the web 1 is not cut completely transverse to its running direction. Rather, there is a large number of incisions in the web 1, a bridge-like web remaining between each incision. In this way, the web 1 is perforated transversely to the direction indicated by the arrow 12. Because of this perforation, it is possible to tear off individual sheets from the web 1 in a later operation. However, it is also possible, for example, for those points at which the web 1 is weakened by transverse perforations to form articulation points in which the web 1 can be folded transversely to its running direction during a later zigzag folding process.

Fig. 1 shows an example of a knife cylinder 3, on the circumference of six knives are arranged evenly distributed. On the other hand, it is also possible to design the knife cylinder 3 in such a way that one, two, three, four, five, seven, eight or ten knives or another number of knives or even another number of knives can be attached to one another evenly or evenly distributed on its circumference. Corresponding to the number of knives provided, there is also the number of grooves used for fastening the knives in the knife cylinder for each knife. In addition, however, it is also possible to incorporate a certain number of grooves in the knife cylinder 3, in contrast to using only a part of these grooves in the respective production process, depending on the present requirement of the production to be achieved.

The knife cylinder 3 and the pressure cylinder 2 are fastened and rotatably mounted in the machine frame 5 in such a way that these machine parts form an assembly as a whole, which can be removed from the main frame 13 of the machine as a whole and exchanged for another similar assembly. For this purpose, it is necessary to fasten the machine frame 5 by means of clamping claws 14 and 15, nuts 16 and 17 and tie rods 18 and 19 screwed into the main frame 13 for the time the machine is running in the main frame 13. However, it is also possible to omit the machine frame 5 and the associated fastening devices and to mount the knife cylinder 3 and the pressure cylinder 2 directly in the main frame 13 of the machine.

From Fig. 2 it can be seen that, for example, six grooves 20, 21, 22, 23, 24 and 25 are incorporated in the knife cylinder 3. Each of the grooves contains a side wall 26, which represents a surface running radially to the cylinder 3. Running parallel to each side wall 26, each groove contains a second side wall 27, which is also incorporated into the knife cylinder 3. The base surface 28 of each groove runs perpendicular to the first side wall 26 and the second side wall 27.

Each groove thus contains the three surfaces 26, 27 and 28. To the radially outside of the knife cylinder 3, each groove is open. An insert 29 is inserted into each groove such that the base 30 of the insert 29 bears against the base 28 of the groove. Each insert 29 contains a bore 31 which passes through this insert completely in its axial direction in such a way that the geometric center of the bore 31 runs parallel to the base 30 of the insert 29. A plurality of bores, for example the bores 32, 33, 34 and 35, are machined into the inserts 29 transversely to their longitudinal direction and also parallel to the base area 30 in such a way that they intersect the bore 31. In addition, a thread is worked into each of the bores 32, 33, 34 and 35, with which bellows cylinders 36, 37, 38 and 39 can be attached to the insert 29. The distance 40, which the threaded holes 32 to 35 occupy with each other, corresponds essentially to the size, i. H. the max. Outside diameter of each bellows cylinder.

The width 41 of each insert 29 and the width 42 of each groove are selected such that commercially available bellows cylinders are screwed into the insert 29 and can be supported against the second side wall 27 in such a way that the knife 6 is positively pressed against the side wall 26 can, in order not to slip while the machine is running relative to the side wall 26 and thus the knife cylinder 3 and the web 1. The bellows cylinders allow a sufficiently high contact pressure, so that sufficiently high pressure forces per knife and a sufficiently large stroke of the respective bellows cylinder and the insert 29 can be achieved in order to remove the knives, for example the knife 6, from the knife cylinder 3 when the stroke subsides can or with a correspondingly low bias against the side wall 26 that all knives, for example the knife 6 can be moved at a slow speed of the knife cylinder 3 and thus slowly passing the printing cylinder 2 such that the knives cooperate optimally with the printing cylinder 2 can. First when the alignment of the knives with respect to the pressure cylinder 2 has been achieved, a higher pressure, the so-called working pressure, is supplied to the bellows cylinders around the respective knife, for example the knife 6, immovably against each side wall 26 of the knife cylinder 3 during operation of the device to press. What has been said here for fastening only one knife applies here, mutatis mutandis, for fastening all other knives to be fastened in all other grooves machined in the knife cylinder 3.

The bores 31, 32, 33, 34 and 35 form a channel system which rotates with the knife cylinder 3. This channel system has two openings, whereby this channel system can be connected to its surroundings, i. H. Pressure medium can be filled in through one opening and the pressure medium can leave the channel system again through the other opening. One opening is closed by a screw 43, which is made possible by the fact that one end of the bore 31 is provided with a thread 44. The other end of the bore 31 is provided with a thread 45 in a similar manner. A special screw 46 is screwed into this thread 45. The special screw 46 contains a bore 47 which is central to it and in which a pressure piston 48 is able to slide. One end of the pressure piston 48 is provided with a thread 49, onto which at least one nut 50 is screwed. Between the nut 50 and the special screw 46, springs, for example disc springs 51, are lined up.

For the purpose of filling the channel system consisting of the bores 31 to 35, the special screw 46 is unscrewed from the insert 29 and the screw 43 is loosened, so that air in the bores can escape and the bores can be filled with pressure medium. When enough pressure medium has been filled into the channel system, the screw 43 is tightened and the special screw 46 is screwed into the thread 45. If the special screw 46 has only been partially screwed into the thread 45, a pressure results in the channel system and thus in the bellows cylinders, which corresponds to the screw-in depth of the special screw 46. In this way, a pre-tensioning force is created for the initial holding and aligning of the knives, for example the knife 6. If, on the other hand, the special screw 46 has been screwed into the thread as much as possible, this results in. a. also due to the position of the nut 50 in the channel system, a pressure and thus a force which is high enough to immovably press the knife 6 against the knife cylinder 3 during operation of the device.

In the exemplary embodiment according to FIG. 5, the bores 31 to 35 are incorporated into a pressure bar 52, the position of the bores corresponding to that in the supplement 29. However, the pressure bar is arranged so that it comes to rest against the second side wall 27 and the bellows cylinder, for example the bellows cylinder 37 presses the knife 6 with the interposition of a relatively narrow second insert 53 against the side wall 26. The bellows cylinders and the knife 6 are tensioned analogously to the exemplary embodiment according to FIG. 2.

The embodiment according to FIG. 6 largely corresponds to that according to FIG. 2, but with the difference that bellows cylinders are selected in the embodiment according to FIG. 6 which do not have the outer contour similar to a sinusoidal line as the bellows cylinders according to FIG. 2. The individual ones The bellows of the bellows cylinder according to FIG. 6 run relatively sharply towards one another and are at their end points or outer max. Diameters 54 welded together in pairs. The bellows cylinders according to the embodiment of FIG. 6 are known per se as so-called membrane bellows, whereas the bellows cylinders of the embodiment according to FIG. 2 are known per se as so-called miniature bellows. Each of the two types of bellows cylinders are made of metal, in particular the bellows made of metal. This metal can be one or more layers. The metal is preferably steel, in particular so-called stainless steel. However, aluminum or brass or some other metal is also possible.

As can be seen from the above, the side wall 26 of each groove faces the knife to be clamped, for example the knife 6, and the second side wall 27 faces away from the knife to be clamped. Both side walls lie essentially radially, this being exactly the case for the first side wall 26 and approximating for the second side wall 27, since this side wall runs parallel to the side wall 26.

As can be seen directly from FIGS. 2 and 5, the insert 29 and the pressure bar 52 have an essentially trapezoidal cross section. The surfaces of the insert 29 facing the knife 6 and the bellows cylinders are parallel to one another, whereas the base surface 30 of the insert 29 runs perpendicular to these two surfaces. The side opposite the base surface 30 is delimited by a piece of a circular arc, the curvature of which is the same as the diameter of the knife cylinder 3 and, due to the selected width 41 of the insert 29, can hardly be regarded as an arc, but rather approximately as a straight line in cross section, for example in FIG. 2. It is also possible that the radially outermost surface of the insert 29 in FIG. 2 represents a plane and not part of a cylinder circumference. In this case, the cross section for the insert 29 would be an exact trapezoid. The same applies analogously to the pressure bar 52. The surfaces of the insert 29 and the pressure bar 52 lying radially on the inside in FIGS. 2 and 5, such as, for example, the base area 30 of the insert 29 correspond to the cross section of the groove 20, in particular the base area 28 of the slot 20. The same applies to the cross sections of the pressure bars and Supplements of the exemplary embodiments according to FIGS. 4 and 6.

If the channel system containing the bores 31 to 35 with a tensioning device after Fig. 3 is provided, then each knife must be individually stretched. However, if one provides a centrally arranged pressure generator according to FIG. 9, which is known per se from EP-A 0 115 783, it is possible to start from a central channel 55 which is in the center of the axis of the knife cylinder 3 and parallel to it in this is incorporated, via connection bores 56, 57, 58, 59, 60 and 61, which are incorporated radially into the knife cylinder 3 and cut the central channel 55, that is to say are connected to it, to loosen, pretension or even clamp all knives at once . Each of the radial connection bores, for example the connection bore 61, is provided with a thread 62 into which a pipe nut 63 can be screwed. The tube nut 63 serves to attach a connecting tube 64 to the knife cylinder 3. With the help of a further connector 65, the other end of the connecting tube 64 can be screwed to the insert 29 such that the pressure medium from the pressure generator of FIG. 9, starting from the central channel 55 and the radial connecting bores 56 to 61, into the bore 31 and so that they can reach the bellows cylinders 36 to 39 and develop pressures or forces there.

Analogously to this, according to the exemplary embodiment of FIG. 8, connecting pipes 66 can be fastened to the knife cylinder 3 with the aid of the pipe nuts 63, the second ends of which can be connected to the bores 31 of the exemplary embodiment according to FIG. 5 by corresponding connecting pieces 65.

The same applies with regard to the exemplary embodiments according to FIGS. 4 and 6. The pipe connections according to FIGS. 7 and 8 can also be used for these exemplary embodiments.

In the embodiment according to FIG. 10, bores or openings 67 are incorporated in the knife cylinder 3 such that they open into the groove 20, for example, and have thus become part of the respective groove. At least one bellows cylinder can be arranged in each opening, which is screwed to an insert 29 provided with a bore 31.

A number of such openings or bores 67 can be arranged one behind the other in the viewing direction of FIG. 10, so that a plurality of bellows cylinders 37, 36, 38 or 39 press the respective knife, for example knife 6, against the side wall 26 of the groove 20 together with the interposition of the insert 29 and tighten it with it.

Within the openings 67, for example, a securing ring 68 can be inserted in a respective groove in order to provide support for the respective bellows cylinder and to enable the bellows cylinder to be mounted from the outside. Here too, the pressure medium cylinders are arranged essentially in the circumferential direction. In this case too, diaphragm, miniature or other bellows can be used. The inserts 29, pressure strips 52, connecting pipes 64 or 66 and the associated screw connections consist of metals such as aluminum or copper or in particular steel, for example stainless steel. Pressure medium, in particular hydraulic oil, is filled into the channel system.

Claims (10)

1. Cutter cylinder (3) for cutting web-like material (1) consisting of paper, plastics or metal foils, fabrics or the like with at least one groove (20-25) provided for receiving and securing respectively one cutter (6-11) located substantially parallel to the axis of rotation of the cutter cylinder (3), likewise located parallel to the axis of rotation of the cutter cylinder (3) on its periphery, cut in the cutter cylinder (3) and pressure points distributed over the length of each cutter (6-11) for bracing the respective cutter (6) with respect to the cutter cylinder (3) by means of several pressure medium cylinders (36-39) distributed over the length of each cutter (6-11 ), pressing the respective cutter (6-11) against the cutter cylinder (3) and with a channel system (31-35) revolving with the cutter cylinder (3) and connected to pressure medium cylinders (36-39), and a connection for the supply and discharge of the pressure medium, and for each cutter (6-11) at least one shim (29-52) located between this cutter and a pressure medium cylinder (36-39) associated therewith, characterised in that the pressure medium cylinders (36-39) associated with each groove (20-25) are located both within the groove (20-25) as well as substantially in the peripheral direction of the cutter cylinder (3), the pressure medium cylinders (36-39) are bellows cylinders and the bellows cylinders are metal.

2. Device according to claim 1, characterised in that the pressure medium cylinders (36-39) are so-called metal bellows.

3. Device according to claim 1, characterised in that the pressure medium cylinders (36-39) are so-called diaphragm bellows.

4. Device according to claim 1, characterised in that the pressure medium cylinders (36-39) are so-called miniature bellows.

5. Device according to claim 1, characterised in that the pressure medium cylinders (36-39) associated with one cutter (6) are attached to the shim (29, 52) associated with each cutter (6-11).

6. Device according to claim 1, characterised in that the pressure medium cylinders (36-39) associated with a cutter (6) are attached to the side wall (26) facing the respective cutter (6) of the two side walls (26, 27) of the respective groove (20-25) cut in the cutter cylinder (3) and arranged substantially radially with respect to the cutter cylinder (3).

7. Device according to claim 1, characterised in that a pressure strip (52) is located between the side wall (27) remote from the respective cutter (6) of the two side walls (26, 27) cut in the cutter cylinder, located substantially radially with respect to the cutter cylinder (3) and the pressure medium cylinders (36-39) associated with the respective cutter (6).

8. Device according to claims 1 and 5, characterised in that at least one part of the channel system (31-35) for the pressure medium is sunk into the shim (29).

9. Device according to claims 1 and 7, characterised in that at least one part of the channel system (31-35) for the pressure medium is sunk in the pressure strip (52).

10. Device according to claims 1 and 7, characterised in that the pressure strip (29) and the shim (52) have a substantially trapezoidal cross-section, the radially inner side of the trapezium corresponding to the cross-section of the groove (20) and the radially outer side of the trapezium corresponding to the periphery of the cutter cylinder (3).

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