Rotary die cutter

Abstract

Rotary punching device (10) for punching a material to be punched, comprising a punching cylinder (14) rotatable about a rotary axis (18) and a magnetic device (50) for attaching a punching sheet (35) to the punching cylinder (14), wherein the magnetic device (50) comprises a first magnet (52) and a second magnet (54), wherein the second magnet (54) is switchable independently of the first magnet (52).

Description

[0001] The present invention relates to a rotary punching device for punching a material to be punched, comprising a punching cylinder which is rotatable about a rotation axis, and a magnetic device for fastening a punching sheet on the punching cylinder.

[0002] An exemplary rotary punching device is known from DE 297 24 092 U1.

[0003] A rotary die-cutting device is used to cut material such as labels, badges, etc. from a material web. The material web runs through a cutting gap formed between the cutting cylinder and an impression cylinder and is cut by one or more cutting edges as it passes through. During cutting, the cutting cylinder and the impression cylinder rotate in opposite directions to each other. In a through-cutting application, the material to be cut out of the material web as a whole, so that the material to be cut falls out of the material web after the cut. In a part-cutting application, the material web is only cut at one point, so that in the case of labels, for example, only the label material and the adhesive are severed, while the backing material remains intact.

[0004] "Punching" in this context also includes perforating, embossing, forming, or indenting. The material to be punched is also referred to as "material to be punched."

[0005] The punching cylinder may have cutting edges machined out of the surface of the punching cylinder or cutting edges formed on a punching sheet clamped on the punching cylinder.

[0006] The use of a cutting die clamped onto the cutting cylinder offers several advantages over cutting edges machined from the surface of the cutting cylinder. When the cutting edges become worn, the cutting die can be easily replaced to restore the functionality of the rotary cutting device. One of the main advantages, however, is that to implement a modified cutting task, for example, to create a different cutting contour, only the cutting die needs to be replaced, while the rest of the rotary cutting device can remain unchanged.

[0007] The cutting die can generally be attached to the cutting cylinder mechanically (positively and / or non-positively, e.g., using screws or a clamp connection) or magnetically. The disadvantages of mechanical attachment are the time required and the tools required to attach and / or release the cutting die. Magnetic attachment of the cutting die to the cutting cylinder, on the other hand, advantageously enables quick and easy clamping and release of the cutting die. Therefore, magnetic attachment of the cutting die has become the standard in practice.

[0008] However, clamping the cutting die onto the cutting cylinder with a magnetic attachment proves to be challenging, particularly with cutting cylinders with large diameters and / or passage widths, and thus cutting dies of large dimensions. This requires considerable experience on the part of the rotary cutting machine operator. The cutting die must be aligned very precisely on the cutting cylinder, which is not easy, as the cutting die is magnetically attracted as it approaches the cutting cylinder. If the cutting die snaps onto the cutting cylinder in an undesirable orientation and adheres to it, this can only be changed subsequently to a limited extent and at least only with additional effort. It goes without saying that this also has a negative impact on setup times.

[0009] It is therefore an object of the present invention to provide a rotary punching device which enables simple and user-friendly assembly of the punching sheet.

[0010] This object is achieved according to the invention on the basis of the rotary punching device mentioned at the outset in that the magnetic device has a first magnet and a second magnet, wherein the second magnet can be switched independently of the first magnet.

[0011] Since the second magnet of the magnetic device can be switched independently of the first magnet, the second magnet can, according to the invention, be switched on and off independently of the first magnet, for example, and thus, for example, the strength of the magnetic field generated by the magnetic device as a whole and / or its polarity can be changed. By switching the second magnet, the magnetic forces exerted by the magnetic device on the stamped sheet can be influenced.

[0012] This makes it possible, for example, to temporally and / or spatially modify the magnetic field generated by the magnetic device during the assembly and / or disassembly of a punching die. In particular, the magnetic field in an area of ​​the punching cylinder (locally or across the entire area) can be weakened or even completely deactivated for a limited period of time during the assembly of a punching die. This greatly simplifies the assembly of the punching die. Disassembly of the punching die can also be simplified.

[0013] The above-mentioned task is thus completely solved.

[0014] In this case, a magnetic force exerted by the magnetic device on the punching sheet or a magnetic field acting on the punching sheet means that the magnetic device generates a magnetic field that can act on the punching sheet clamped onto the punching cylinder. This refers in particular to the magnetic field generated by the magnetic field device in the area of ​​the outer surface of the punching cylinder, which can act accordingly on the punching sheet clamped onto the outer surface of the punching cylinder.

[0015] According to a preferred embodiment, the magnetic device is arranged in or on the punching cylinder.

[0016] In principle, various geometric arrangements of the magnetic device are possible within or on the punching cylinder. For example, the first magnet and the second magnet can each be arranged parallel to or along the rotational axis of the punching cylinder and / or along the circumferential direction of the punching cylinder. The distance of the first magnet from the rotational axis of the punching cylinder can be the same as or different from the distance of the second magnet from the rotational axis of the punching cylinder.

[0017] According to one embodiment, the magnetic device can be switched between an assembly state and a punching state by switching the second magnet.

[0018] To mount the punching die on the punching cylinder, the second magnet can be switched to the assembly state accordingly, simplifying assembly for the operator. The second magnet can then be switched to the punching state before or at the start of the punching process. Preferably, the magnetic field generated by the first magnet remains unchanged.

[0019] According to another embodiment, a force exerted by the magnetic device on the punching sheet in the assembly state is zero or at least smaller than a force exerted by the magnetic device on the punching sheet in the punching state.

[0020] The magnetic field generated by the magnetic device in the area of ​​the outer surface of the punching cylinder, which can act on a clamped punching sheet, is therefore at least partially stronger in the punching state than in the assembled state.

[0021] Advantageously, the punching sheet can thus be positioned more easily on the punching cylinder in the assembled state of the magnetic device, while the punching sheet is still securely fastened to the punching cylinder in the punching state of the magnetic device.

[0022] According to a further embodiment, in the assembled state, the first magnet and / or the second magnet generates a magnetic field.

[0023] Particularly preferably, both the first magnet and the second magnet generate a magnetic field in the assembled state, while in the punched state, only the first magnet generates a magnetic field. This is particularly advantageous if the second magnet is an electrically switchable magnet, since it then does not need to be energized in the punched state.

[0024] According to a preferred embodiment, the magnetic device exerts a magnetic force on at least a partial area of ​​the punched sheet in the assembled state.

[0025] The force refers specifically to the resulting attractive force between the punching cylinder and the punching die. The magnetic fields generated by the first and second magnets can, for example, counteract or reinforce each other.

[0026] In the assembled state, a magnetic (attractive) force can thus be exerted on at least a portion of the punching die. Advantageously, this makes it possible to hold the punching die positioned on the punching cylinder in position in the assembled state (relative to the magnetic device). This can prevent unintentional movement (e.g., slipping) of the punching die in the assembled state before the punching die is secured in a fixed position on the punching cylinder by means of magnetic holding force in the punching state.

[0027] According to another embodiment, the magnetic device is designed to exert a magnetic force on a first region of the punched sheet in the assembled state, which magnetic force per unit area is lower than a magnetic force per unit area exerted by the magnetic device on a second region of the punched sheet in the assembled state.

[0028] The magnetic flux density in the first region of the punching sheet (or in a first region of the outer surface of the punching cylinder) thus differs from the magnetic flux density in the second region of the punching sheet (or in a second region of the outer surface of the punching cylinder). The (attractive) force exerted by the punching cylinder on the clamped punching sheet thus differs in the first region and in the second region. Preferably, the exertable (attractive) force per unit area is smaller in the first region of the punching sheet (or the outer surface of the punching cylinder) than in the second region of the punching sheet (or the outer surface of the punching cylinder).

[0029] Advantageously, to clamp the cutting die, the operator can, for example, position the first section of the cutting die in the first area of ​​the outer surface of the cutting cylinder, which could be a positioning area, relative to the cutting cylinder, and adjust the position of the cutting die. Once the cutting die is correctly positioned, the second section of the cutting die can also be applied to the second area of ​​the outer surface of the cutting cylinder, and the magnetic device can be switched to the cutting state.

[0030] According to a further embodiment, the magnetic device is designed to at least locally weaken a magnetic field formed by the first magnet by switching the second magnet in the assembled state.

[0031] The second magnet can thus generate a magnetic field which counteracts the magnetic field generated by the first magnet in a region of the punching sheet or in a region of the outer surface of the punching cylinder. For example, the first magnet generates a first magnetic field which has an attractive effect on the entire punching sheet, and the second magnet generates a second magnetic field which has a repulsive effect on a region of the punching sheet. It is understood that this latter region of the punching sheet can comprise either part of the punching sheet or the entire punching sheet. In other words, in this embodiment, the first magnetic field generated by the first magnet can be temporarily weakened or even completely eliminated with the help of the second magnet, either only in a region of the outer surface of the punching cylinder or across the entire outer surface.

[0032] According to a preferred embodiment, the first magnet is designed to exert a first force on the punched sheet in the assembled state, and the second magnet is designed to exert a second force on the punched sheet in the assembled state, which second force at least partially counteracts the first force.

[0033] For example, the first force is an attractive force between the punching cylinder and the punching die, and the second force is a repulsive force between the punching cylinder and the punching die. If the second force is smaller than the first force, a force will still act on the punching die in the assembled state, but this force will be smaller than the force exerted on the punching die in the punching state.

[0034] According to another embodiment, the first magnet is a permanent magnet.

[0035] Advantageously, the first magnet does not need to be supplied with power either in the punching state or in the assembly state. This has a positive effect on energy consumption and simplifies the design of the rotary punching device (e.g., with regard to the power supply of the rotating punching cylinder). This also has a positive effect on safety, as the punching cylinder does not need to be protected against power failure in the punching state.

[0036] According to a further embodiment, the second magnet can be switched electrically and / or mechanically.

[0037] The second magnet can, for example, be an electromagnet that can be controlled via the power supply. Likewise, the second magnet can, for example, comprise one or more permanent magnets that can be mechanically switched via their spatial orientation (and thus relative to the punched sheet) and / or their orientation relative to one another.

[0038] According to a preferred embodiment, the rotary punching device has a switching device that can be actuated by an operator for switching the second magnet.

[0039] The switching device can be activated mechanically, via voice recognition, and / or visual recognition. This allows for user-friendly installation by the operator.

[0040] Preferably, the switching device comprises a foot-operated device, such as a push button, which the operator can actuate with their foot. In this way, the operator can actuate the switching device, for example, with their foot to switch the magnetic device between the punching state and the assembly state, while simultaneously holding the punching die with their hands to position it on the punching cylinder.

[0041] According to a further embodiment, the magnetic device can be switched between a punching state and a disassembly state by switching the second magnet and is designed to exert a magnetic force on the punching sheet in the disassembly state, by means of which force at least a region of the punching sheet is lifted off the punching cylinder.

[0042] In the disassembled state, a magnetic field can be generated by the magnetic device in at least one area of ​​the punching cylinder, which field exerts a magnetic repulsion force on the clamped punching sheet, so that the punching sheet is lifted off the punching cylinder in the area.

[0043] For example, in the disassembled state, the second magnet can generate a magnetic field that is stronger in the region of the punching sheet (or in a corresponding region of the punching cylinder) than the magnetic field generated by the first magnet and has a polarity opposite to the magnetic field generated by the first magnet.

[0044] Advantageously, the lifted portion of the punching plate can be easily grasped and thus easily removed from the punching cylinder.

[0045] It is understood that the cutting die can also be repelled from the cutting cylinder over its entire circumference. However, the cutting die is preferably repelled from the cutting cylinder only in a first region, so that the cutting die is spaced from the cutting cylinder only in the first region, while the cutting cylinder exerts a holding force on the cutting die in a second region. This prevents the cutting die from accidentally becoming completely released (falling down), which could damage the cutting die and / or injure an operator.

[0046] According to a further embodiment, the rotary punching device has a disassembly device which is designed to at least partially lift the punching sheet from the punching cylinder.

[0047] The disassembly device may comprise a mechanical or electromechanical actuator (e.g. an ejector pin or a spring element), a magnetic actuator (e.g. a lifting magnet) or a pneumatic actuator (e.g. a compressed air nozzle) or a hydraulic actuator.

[0048] For example, the disassembly device has one or more air supply openings through which compressed air can be supplied to expel the punching sheet from the punching cylinder. Alternatively or additionally, the disassembly device can have one or more ejector elements (e.g., ejector pins) that are movable radially relative to the punching cylinder, which are retracted into the punching cylinder in the punching state and can be extended radially to space the punching sheet from the punching cylinder.

[0049] Further preferably, the disassembly device is designed to be actuated by means of a switching device that can be actuated by the operator, in particular by means of a push button and / or a foot actuating device.

[0050] According to a preferred embodiment, the rotary punching device has a permanent magnetic or magnetizable punching sheet which can be applied to the punching cylinder.

[0051] The punching die has one or more cutting edges designed to cut a material to be punched.

[0052] According to a further preferred embodiment, the rotary punching device further comprises an impression cylinder which is rotatable about an axis of rotation parallel to the axis of rotation of the punching cylinder, wherein the punching cylinder and the impression cylinder form a punching gap for the passage of the material to be punched between the punching cylinder and the impression cylinder.

[0053] The material to be punched can pass through the punching gap formed between the punching cylinder and the impression cylinder as a web or sheet material and be punched as it passes through.

[0054] It is understood that the features mentioned above and to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0055] Embodiments of the invention are illustrated in the drawings and will be described in more detail below with reference to them. They show: Fig. 1 is a schematic front view of a rotary punching device in interrupted representation; Fig. 2 is a sectional view of the Fig. 1 shown rotation device; Fig. 3 is a perspective view of a punching cylinder according to a first embodiment of the present invention; Fig. 4 is a schematic sectional view of the Fig. 3 shown punching cylinder; Fig. 5 is a schematic sectional view of the punching cylinder according to a second embodiment of the present invention; Fig. 6 is a schematic sectional view of the punching cylinder according to a third embodiment of the present invention; Fig. 7 is a schematic sectional view of the punching cylinder according to a fourth embodiment of the present invention; and Fig. 8 is a schematic sectional view of the punching cylinder according to a fifth embodiment of the present invention.

[0056] Fig. 1 and Fig. 2 show a schematic front view and a schematic sectional view of a rotary punching device 10. The rotary punching device 10 is in Fig. 1 shown interrupted along two lines 12. The Fig. 2 For example, the section shown runs along one of the lines 12 in Fig. 1 .

[0057] The rotary punching device 10 has a punching cylinder 14 and an impression cylinder 16. The punching cylinder 14 is rotatable about a first rotational axis 18, and the impression cylinder 16 is rotatable about a second rotational axis 20, which runs parallel to the first rotational axis 18. The punching cylinder 14 is mounted via axle journals 22 and 24, and the impression cylinder 16 is mounted via axle journals 26 and 28 in side parts 30 and 32 of a frame 34 of the device 10 ( Fig. 1 ).

[0058] A punching plate 35 with cutting edges formed on the punching plate 35 is clamped over its entire circumference on the punching cylinder 14. The punching plate 35 is secured over the circumference of the punching cylinder 14 and along the rotational axis 18 of the punching cylinder 14 by a magnetic holding force.

[0059] The punching cylinder 14 with punching plate 35 and the impression cylinder 16 form a punching gap 36 for the passage of a material to be punched. The material to be punched is typically guided through the punching gap 36 in the form of a material web (not shown) and punched by means of the cutting edges of the punching plate 35.

[0060] During punching operation, the punching cylinder 14 and the counter-pressure cylinder 16 rotate in opposite directions to each other, as indicated by arrows 46 and 48 ( Fig. 2 ). The drive for rotating the punching cylinder 14 and the impression cylinder 16 can be provided by an electric motor drive (not shown). The drive can drive the punching cylinder 14 and the impression cylinder 16 jointly; separate drive of the cylinders is also possible.

[0061] The punching cylinder 14 further has bearer rings 42 and 44 outside the cutting area. The impression cylinder 16 has bearer rings 42 and 44, with the bearer rings 38 and 40 rolling on the bearer rings 42 and 44 as the punching cylinder 14 and the impression cylinder 16 rotate.

[0062] Fig. 3 and Fig. 4 show a perspective view and a schematic sectional view of a first embodiment of the punching cylinder 14. The punching cylinder 14 has a magnetic device 50 with a first magnet 52 and a second magnet 54 that can be switched independently of the first magnet 52.

[0063] In the illustrated embodiment, the first magnet 52 is a (non-switchable) permanent magnet. The first magnet 52 therefore does not require a power supply per se. The second magnet 54, on the other hand, is a switchable electromagnet that can be switched between an assembly state and a punching state independently of the first magnet 52. The power supply for, or switching on, the second magnet 54 is via a contact pin 56.

[0064] The first magnet 52 is cylindrical and arranged on the rotational axis 18 of the punching cylinder 14. This arrangement advantageously promotes smooth running of the punching cylinder.

[0065] The second magnet 54 is rod-shaped or strip-shaped and runs parallel to the rotational axis 18 of the punching cylinder 14. In this embodiment, the second magnet 54 is further away from the rotational axis 18 than the first magnet 52. The second magnet 54 closes in the Fig. 1 shown embodiment with the outer surface 57 of the punching cylinder 14. Alternatively, the second magnet 54 can be spaced from the outer surface 57 of the punching cylinder and, for example, covered by a protective cover.

[0066] During punching operation, the punching plate 35 ( Fig. 4 ) is secured to the punching cylinder 14 by a magnetic (attraction or holding) force exerted by the magnetic device 50. The second magnet 54 is deactivated in the punching state. Thus, no current needs to be supplied to the magnetic device 50 in the punching state.

[0067] If the magnetic device 50 is in the punching state, the punching plate 35 can only be positioned on the punching cylinder 14 by an operator with difficulty (with the punching cylinder 14 and impression cylinder 16 not driven), since positioning, such as moving the punching plate 35, requires working against the magnetic holding force exerted on the punching plate 35 by the magnetic device 50. However, the holding force must be sufficiently large so that the punching plate 35 can be securely held on the punching cylinder 14 during the punching operation.

[0068] To mount the punching plate 35 on the punching cylinder 14, the second magnet 54 is switched to the mounting state so that the operator can more easily position the punching plate 35 on the punching cylinder 14.

[0069] The second magnet 54 is switched via a switching device 55 that can be actuated by an operator, for example, a push button and / or a foot-operated device. Alternatively, the switching device 55 can be switched automatically.

[0070] In the assembled state, the second magnet 54 is connected such that the magnetic field generated by the magnetic device 50 differs in a first region 60 of the outer surface 57 of the punching cylinder 14 from that in a second region 64 of the outer surface 57 of the punching cylinder 14. In the first region of the outer surface 62 of the punching cylinder 14 or in a corresponding first region 58 of a punching sheet 35 clamped onto the punching cylinder 14, a first magnetic field formed by the first magnet 52 is attenuated by a second magnetic field formed by the second magnet 54. The force exerted (resulting) by the second magnet 54 on the clamped punching sheet 35 acts here opposite to the force exerted (resulting) by the first magnet 52 on the punching sheet 35.Thus, in the assembled state, the punched sheet 35 is attracted less strongly by the magnetic device 50 in a first region 58 of the punched sheet 35 than in a second region 60 of the punched sheet 35.

[0071] If the punching sheet 35 is clamped and positioned on the punching cylinder 14, the second magnet 54 can be switched from the assembly state to the punching state during or before the start of the punching operation.

[0072] To disassemble the punching die 35, the second magnet 54 is switched from the punching state to a disassembly state. Disassembly to replace the punching die 35 can be performed, for example, to replace a punching die 35 with worn cutting edges or to adapt the cutting edges to a different punching geometry.

[0073] In the disassembly state, the second magnet 54 is connected such that the second magnet 54 exerts a magnetic (repulsive) force on the punching sheet 35. The magnetic device 50 as a whole acts repulsively on the punching sheet 35 in the first region 58 of the punching sheet 35 and attractively in the second region 60 of the punching sheet 35. The magnetic field generated in the first region 60 of the punching cylinder 14 or the magnetic field acting on the first region 58 of the punching sheet 35 is thus polarized in the disassembly state opposite to the magnetic field acting on the punching sheet 35 in the second region 60 of the punching sheet 35. This allows an operator or a robot to more easily grasp the punching sheet 35 in the first region 58 without the punching sheet 35 as a whole becoming detached from the punching cylinder.

[0074] The rotary punching device 10 further comprises a disassembly device 66, which can be provided in addition to or alternatively to the disassembly function of the magnetic device 50 in order to simplify the disassembly of the punching sheet 35. The disassembly device 66 is configured to lift the punching sheet 35 at least partially from the punching cylinder 14. For this purpose, the disassembly device 66 has a plurality of ejector elements (not shown) that are movable in the radial direction of the punching cylinder 14 and are arranged in the first region 62 of the punching cylinder 14. In the punching state, the ejector elements are retracted into the punching cylinder 14 and are extended in the radial direction to space the punching sheet 35 from the outer surface 57 of the punching cylinder 14.

[0075] Additionally or alternatively, the disassembly device 66 can have air supply openings that open into the outer surface 37 of the punching cylinder 14. Compressed air can be supplied through the air supply openings, which presses the clamped punching sheet 35 away from the punching cylinder 14. The disassembly device 66 thus supports the operation of the second magnet 54 in the disassembly state.

[0076] Fig. 5-8 show further embodiments of the rotary punching device 10 or of the punching cylinder 14 belonging to the rotary punching device 10, wherein the embodiments shown therein differ from the one shown in Fig. 3 and Fig. 4 shown embodiment essentially by the type of design of the magnetic device 50. In addition to the different arrangement of the first magnet 52 and / or the second magnet 54, in the Fig. 3-8 In the embodiments shown, the first magnet 52 can vary between a (non-switchable) permanent magnet and a (switchable) electromagnet. Furthermore, the first magnet 52 can generate a magnetic field in the assembled state and / or in the punched state. The second magnet 54 can be mechanically or electrically switchable. Furthermore, the second magnet 54 can generate a magnetic field in the assembled state and / or in the punched state.

[0077] Fig. 5 shows a second embodiment of the punching cylinder 14, in which, in comparison to the one in Fig. 3 and Fig. 4 In the first embodiment shown, the second magnet 54 is arranged over the entire circumference of the punching cylinder 14. In the assembled state, the magnetic field generated by the first magnet 52 is thus weakened or even completely neutralized over the entire circumference of the punching cylinder 14 by means of the second magnet 54. Even in the disassembled state, in contrast to the first embodiment ( Fig. 3 and Fig. 4 ) the punching sheet 35 is only repelled as a whole by the magnetic device 50.

[0078] It is understood that the second magnet 54 may also have a plurality of magnetic elements, which may, for example, be arranged at regular intervals over the circumference of the outer surface 57 of the punching cylinder 14.

[0079] Fig. 6 shows a third exemplary embodiment in which the first magnet 52 and the second magnet 54 are spaced apart from the rotational axis 18 of the punching cylinder 14 and are at the same distance from the rotational axis 18. The first magnet 52 has several (here, for example, five) magnetic elements. The first magnet 52 with the five magnetic elements and the second magnet 54 are arranged uniformly at regular intervals around the circumference of the punching cylinder 14 or the outer surface 57 of the punching cylinder 14. The magnetic elements of the first magnet 52 and the second magnet 54 extend in a rod-like (or strip-like) manner parallel to the rotational axis 18 of the punching cylinder 14.

[0080] In the punching state, the second magnet 54 is connected such that the second magnet 54 attracts the clamped punching sheet 35, so that the punching sheet 35 is fastened to the punching cylinder 14 by a holding force exerted by the first magnet 52 and the second magnet 54.

[0081] In the assembled state, the second magnet 54 is switched off or connected such that the second magnet 54 exerts a lower attractive force on the clamped punching sheet 35 (not shown) than in the punching state. The first magnet 52 generates the same magnetic field in the punching state and in the assembled state. Thus, the magnetic field generated by the magnetic device 50 in the first region 62 of the punching cylinder differs from the magnetic field generated in the second region 64 of the punching cylinder. In particular, the magnetic flux density in the second region 64 is greater than in the first region 62. Thus, the first region 58 of the punching sheet 35 (relative to a unit area) is less strongly attracted to the magnetic device 50 than the second region 60 of the punching sheet 35.

[0082] Fig. 7 shows a fourth embodiment in which the second magnet 52 is cylindrical and is arranged on the rotational axis 18 of the punching cylinder 14. The first magnet 54 is arranged completely around the circumference of the punching cylinder 14 and on the outer surface 57 of the punching cylinder 57. This corresponds to a Fig. 3 and Fig. 4 shown first embodiment reversed arrangement of the first magnet 52 and the second magnet 54.

[0083] Fig. 8 shows a fifth embodiment in which the first magnet 52 has several (here, for example, six) equally sized magnetic elements arranged at regular intervals along the circumference of the punching cylinder 14 and on the outer surface 57 of the punching cylinder 14. The second magnet 54 is arranged on the rotational axis 18 of the punching cylinder 14. The magnetic elements of the first magnet 52 extend in a rod-like (or strip-like) manner parallel to the rotational axis 18 of the punching cylinder 14.

[0084] It is understood that the exemplary embodiments shown in the figures merely show exemplary configurations of the container according to the invention, which are intended to illustrate the advantages of the container according to the invention. Various modifications can be made to these exemplary embodiments without departing from the scope of the present invention. For example, the connection of the second magnet can also be effected via a contact loop on the outer side and / or raceway of the punching cylinder. Furthermore, further geometric variations in the arrangement and / or size / size ratio of the first magnet and second magnet are possible. For example, the magnetic device can have different distances from the axis of rotation of the punching cylinder than in the exemplary embodiments shown. The magnetic device can also be arranged close to the outer surface of the punching cylinder and, for example, be covered by a protective cover.Furthermore, the repulsion force exerted by the magnetic device on the punching die from the punching cylinder can be applied only partially or completely. It is also understood that the assembly and disassembly of the punching die can be performed either manually by an operator or automatically using an assembly and disassembly device.

[0085] List of reference symbols 10Rotary punching device 12Lines 14Punching cylinder 16Impression cylinder 18First rotary axis 20Second rotary axis 22, 24Punching cylinder journal 26, 28Impression cylinder journal 30, 32Side part 34Frame 35Punching plate 36Punching gap 38, 40Bearer rings of the punching cylinder 42, 44Bearer rings of the impression cylinder 46, 48Arrows 50Magnet device 52First magnet 54Second magnet 55Switching device 56Contact pin 57Shell surface 58First area of ​​the punching plate 60Second area of ​​the punching plate 62First area of ​​the punching cylinder 64Second area of ​​the punching cylinder 66Disassembly device

Claims

1. Rotary punching device (10) for punching a material to be punched, with a punching cylinder (14) which is rotatable about a rotation axis (18), and a magnetic device (50) for fastening a punching sheet (35) on the punching cylinder (14), wherein the magnetic device (50) has a first magnet (52) and a second magnet (54) which is switchable independently of the first magnet (52).

2. Rotary punching device (10) according to claim 1, wherein the magnetic device (50) is switchable between an assembly state and a punching state by switching the second magnet (54).

3. Rotary punching device (10) according to claim 2, wherein a force exerted by the magnetic device (50) on the punching sheet (35) in the assembled state is zero or at least smaller than a force exerted by the magnetic device (50) on the punching sheet (35) in the punching state.

4. Rotary punching device (10) according to claim 2 or 3, wherein in the assembled state the first magnet (52) and / or the second magnet (54) generates a magnetic field.

5. Rotary punching device (10) according to one of claims 2 to 4, wherein the magnetic device (50) in the assembled state exerts a magnetic force on at least a partial area of ​​the punching sheet (35).

6. Rotary punching device (10) according to one of claims 2 to 5, wherein the magnetic device (50) is designed to exert a magnetic force on a first region (58) of the punching sheet (35) in the assembled state, which magnetic force per unit area is less than a magnetic force per unit area exerted by the magnetic device (50) on a second region (60) of the punching sheet (35) in the assembled state.

7. Rotary punching device (10) according to one of claims 2 to 6, wherein the magnetic device (50) is designed to at least locally weaken a magnetic field formed by the first magnet (52) by switching the second magnet (54) in the assembled state.

8. Rotary punching device (10) according to one of claims 2 to 7, wherein the first magnet (52) is designed to exert a first force on the punching sheet (35) in the assembled state, and the second magnet (54) is designed to exert a second force on the punching sheet (35) in the assembled state, which second force at least partially counteracts the first force.

9. Rotary punching device (10) according to one of the preceding claims, wherein the first magnet (52) is a permanent magnet.

10. Rotary punching device (10) according to one of the preceding claims, wherein the second magnet (54) is electrically and / or mechanically switchable.

11. Rotary punching device (10) according to one of the preceding claims, further comprising a switching device (55) operable by an operator for switching the second magnet (54), which in particular comprises a push button and / or a foot actuating device.

12. Rotary punching device (10) according to one of the preceding claims, wherein the magnetic device (50) is switchable between a punching state and a disassembly state by switching the second magnet (54) and is configured to exert a magnetic force on the punching sheet (35) in the disassembly state, by means of which at least a region (58, 60) of the punching sheet (35) is lifted off the punching cylinder (14).

13. Rotary punching device (10) according to one of the preceding claims, comprising a disassembly device (66) which is designed to at least partially lift the punching sheet (35) from the punching cylinder (14).

14. Rotary punching device (10) according to one of the preceding claims, comprising a permanently magnetic or magnetizable punching sheet (35) which can be applied to the punching cylinder (14).

15. Rotary punching device (10) according to one of the preceding claims, comprising an impression cylinder (16) which is rotatable about an axis of rotation (20) parallel to the axis of rotation (18) of the punching cylinder (14), wherein the punching cylinder (14) and the impression cylinder (16) form a punching gap (36) for the passage of the material to be punched between the punching cylinder (14) and the impression cylinder (16).

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