EP2487015B1 - Device for punching moving sheets of material - Google Patents

Description

The present invention relates to an apparatus for punching or perforating moving webs of material.

In the DE 103 14 959 A1 a punching unit is disclosed which has a plurality of punching tools mounted on an axis, the distance between which is adjustable and which are intended to work together with an impression cylinder. Each punching tool has a cylindrical disc, on the circumference of which a metal strip provided with punched profiles is detachably held.

From the DE 298 05 004 U1 Another embodiment of a punching tool is known, which also has a cylindrical disk, on the circumference of which a punched sheet metal provided with a punched profile is detachably held. This punching tool is provided with a device for sucking in and later releasing the punched-out parts (diecuts).

The US 2007/0000367 A1 discloses a rotary cutting tool with a rotatable punch cylinder having an axis of rotation, a pair of side members and a cylindrical surface, with a punch plate disposed around the cylindrical surface of the punch cylinder and rigidly attached to the punch cylinder in a first position, and with an adjustable slide assembly which operatively connects the die plate to the tool cylinder in a second position and which is displaceable relative to the die cylinder between a retracted and an extended position. The adjustable The sliding arrangement is displaceable either along a first direction about the axis of rotation of the punching cylinder or along a second direction parallel to the axis of rotation of the punching cylinder.

From the U.S. 5,088,367 Finally, rotatable punching cylinders for cutting out blanks from thin metal sheets or material webs are known. The punching cylinders have cooperating cutting knives, some of which are carried by means of punching segments which are mounted on the punching cylinders in axially and / or circumferentially set positions.

The DE 103 14 959 A1 describes a cutting tool which comprises a disc mounted on a rotatable axis, which is arranged adjacent to an impression cylinder, wherein the material web can be passed between the disc and the impression cylinder. Magnets are arranged on the circumference of the disk, by means of which a metal strip provided with cutting and standing profiles is held. The disks can be adjustably mounted on the axle. As a result, different geometries can be cut or punched with the cutting tool by exchanging the metal strips and, furthermore, the metal strip can easily be exchanged as a wear part.

The present invention is based on the object of creating a device for punching moving material webs which allows the arrangement and / or the shape (contour) of the parts to be punched (diecuts) to be changed in a simple and time-saving manner.

According to the invention, this object is achieved with a device which has the features of claim 1. Preferred further developments of the device according to the invention form the subject matter of claims 2-13.

Fig. 1

in einer perspektivischen Ansicht eine Stanzeinheit mit einem Stanzwerkzeug,

Fig. 2

in einem Längsschnitt eine Stanzeinheit mit zwei Stanzwerkzeugen,

Fig. 3

die Stanzeinheit gemäss Fig. 2 in einem Querschnitt,

Fig. 4

in einer perspektivischen Ansicht ein Stanzwerkzeug,

Fig. 5

in einer perspektivischen Ansicht eine erste Ausführungsform einer Stanzvorrichtung mit zwei Stanzeinheiten,

Fig. 6

in einer perspektivischen Ansicht eine erste Ausführungsform einer Stanzvorrichtung mit drei Stanzeinheiten,

Fig. 7

in einer perspektivischen Ansicht eine zweite Ausführungsform einer Stanzvorrichtung mit zwei Stanzeinheiten,

Fig. 8

in einer perspektivischen Ansicht eine zweite Ausführungsform einer Stanzvorrichtung mit drei Stanzeinheiten,

Fig. 9

in einer perspektivischen Ansicht und vereinfacht das Stanzen von Lochungen in einer Materialbahn,

Fig. 10

in einer Seitenansicht und vereinfacht ein Stanzwerkzeug mit der zu bearbeitenden Materialbahn,

Fig. 11

in einer schematischen Darstellung den Verlauf der Drehgeschwindigkeit des Stanzwerkzeugs bei verschiedenen Stanzsituationen,

Fig. 12

ein Blockschema der Steuerung für eine Stanzeinheit.

The subject matter of the invention is explained in more detail below with reference to the figures. It shows purely schematically:

Fig. 1

in a perspective view a punching unit with a punching tool,

Fig. 2

in a longitudinal section a punching unit with two punching tools,

Fig. 3

the punching unit according to Fig. 2 in a cross section,

Fig. 4

in a perspective view a punching tool,

Fig. 5

in a perspective view a first embodiment of a punching device with two punching units,

Fig. 6

in a perspective view a first embodiment of a punching device with three punching units,

Fig. 7

in a perspective view a second embodiment of a punching device with two punching units,

Fig. 8

in a perspective view a second embodiment of a punching device with three punching units,

Fig. 9

in a perspective view and simplifies the punching of holes in a material web,

Fig. 10

in a side view and simplified a punching tool with the material web to be processed,

Fig. 11

a schematic representation of the course of the rotational speed of the punching tool in different punching situations

Fig. 12

a block diagram of the control for a punching unit.

When "punching" is used in the following description of the figures as well as in the claims, this term is understood to mean both the actual punching (severing) and perforation, in which the perforated part is connected to the web of material via weakening points (perforations) remains connected temporarily and is only released later.

Based on Figures 1 to 4 the structure of two different embodiments of punching units 1 and 1 'is described. The only difference between the two embodiments is that the punching unit 1 ( Fig. 1 ) a punching tool 2 and the punching unit 1 'has two punching tools 2, 2', which are of the same construction.

The punching tools 2 or 2, 2 'are connected in a rotationally fixed manner to a drive shaft 3, which in the present exemplary embodiments is a spline shaft. The Drive shaft 3 is rotatably mounted about its axis of rotation 3a and connected to a drive device, not shown. Each punching tool 2 or 2 'is rotatably mounted in a tool holder 4 and can be displaced with this in the direction of the axis of rotation 3a of the drive shaft 3 along this into different working positions. The punching tools 2, 2 'work together with an impression cylinder 5, which is mounted rotatably about its axis of rotation 5a and is connected to a drive device (not shown). Each punch 2, 2 'is mounted in such a way, e.g. using a radial coupling, that the distance between the punch 2, 2' and the impression cylinder 5 can be set individually ( Figs. 2 and 3 ). The impression cylinder 5 has a smooth surface which is preferably hardened. The axis of rotation 3a of the drive shaft 3 and the axis of rotation 5a of the impression cylinder 5 run parallel to one another.

The punching tools 2, 2 'are guided by means of a guide 6 (sliding guide) which is formed on the underside of a guide bar 7 and which extends over the entire working width of the punching unit 1. This guide 6 runs parallel to the axis of rotation 5a of the impression cylinder 5. A correspondingly designed guide 8, which is designed on the tool holder 4, interacts with the guide 6 (see in particular Fig. 3 ). The tool holder 4 and with it also the punching tools 2, 2 'can be moved translationally along the guide 6 between different working positions. By means of a locking device 9 (only shown schematically) Fig. 3 ) the punching tool 2, 2 'can be locked in any working position. It is also possible for the Figure 2 shown punching unit 1 ' to adjust the mutual distance between the punching tools 2, 2 ', that is to say to change.

In the Fig. 4 the structure of the punching tool 2 or 2 'is shown. The punching tool 2 or 2 'has a cylindrical base body 10, on the circumference of which a punching strip 11 is detachably held. The punched strip 11 is preferably a metal strip that is held on the base body 10 by means of magnetic force. The punched strip 11 is provided with a number of punching dies 12 which are arranged distributed over the length of the punched strip 11. The distances between the cutting dies 12 can be the same or different. The cutting dies 12 can have the same shape or different shapes (contours). On the circumference of the base body 10, positioning pins 13 are provided which, when the punched strip 11 is installed, engage in positioning holes 14 on the punched strip 11. In this way, the punching tape 11 is correctly positioned. It goes without saying that the punched strips 11 can also be attached to the base body 10 in an exchangeable manner in another suitable manner. In this context, reference is made to those already mentioned, for example DE 103 14 959 A1 and DE 298 05 004 U1 referenced. It is also conceivable to arrange several punched strips 11 on the circumference of the base body 10.

More than two punching tools 2 can also be provided on the drive shaft 3 for each punching unit 1, 1 ′.

Based on Figures 5 to 8 Embodiments of punching devices 15 and 16 are described which have two punching units 1a, 1b or three punching units 1a, 1b, 1c, which, viewed in the direction of movement A of a material web 17 to be processed, one behind the other are arranged. The structure of the punching units 1a, 1b, 1c corresponds to that in FIG Figures 2 and 3 punching unit 1 'shown and each have two punching tools 4. Corresponding parts are therefore in the Figures 5 to 8 the same reference numerals are used as in Figures 1 to 4 .

The ones in the Figures 5 and 6 The exemplary embodiments shown differ from one another only in a different number of punching units 1a, 1b and 1a, 1b, 1c. In both exemplary embodiments, the punching tools 2 of one punching unit 1a are displaced in relation to the punching tools 2 ', 2 "of the other punching unit 1b or 1c in the direction of the axis of rotation 3a of the drive shafts 3, i.e. in a direction that is transverse, in particular at right angles, to The direction of movement A of the material web 17. The punching tools 2 'of the punching unit 1b are also offset with respect to the punching tools 2 "of the punching unit 1c. This means that the punching tools 2 of the punching units 1 a, 1 b, 1 c process different areas of the material web 17.

In the embodiment according to Fig. 5 The punching tools 2 of the punching unit 1a are used to punch holes 18, 18 'in the section 17a of the material web 17, which for example serve as storage holes, while the tools 2' of the second punching unit 1b punch holes 18, 18 'in the material web section 17b be punched. As the Fig. 5 shows, different punchings can be made in the two material web sections 17a, 17b. For example, in the material web section 17a, the areas a and c are provided with holes 18, 18 ', while the area b is not punched having. In contrast, in the material web section 17b, the perforations 18, 18 'are made in the areas e and f, while the area d has no punching.

The same applies accordingly to the embodiment according to Fig. 6 , in which three sections 17a, 17b, 17c of the material web 17 can be processed differently. The tools 2 of the punching tool 1a process the material web section 17a, the punching tools 2 'of the punching tool 1b, the material web section 17b and the punching tools 2 ″ of the punching tool 1c the material web section 17c.

As the Fig. 6 shows, adjacent areas a, d, g or b, e, h or c, f, e of the material web sections 17a, 17b, 17c are processed differently.

The embodiments according to Figures 7 and 8 also differ from one another only in a different number of punching units 1a, 1b and 1a, 1b, 1c. In both embodiments, a punching tool 2, 2 ', 2 "of a punching unit 1a, 1b, 1c, viewed in the direction of movement A of the material web 17, is aligned with a punching tool 2, 2' or 2" of another punching unit 1a, 1b or 1c.

In the case of the Fig. 7 The embodiment shown is in each case one of the punching tools 2 of the punching unit 1a aligned with a punching tool 2 'of the other punching unit 1b. Each pair of punching tools 2, 2 'aligned with one another makes perforations 18, 18' in one of the two material web sections 17a, 17b. In this case, one of the two holes 18 or 18 ', which are in a material web area a, c, d or f are attached, punched by the punching tool 2 of the punching unit 1a and the other of the two holes 18, 18 'of the punching tool 2' of the other punching unit 1b.

In the embodiment according to Fig. 8 The aligned punching tools 2, 2 "of the punching units 1a, 1c are used to punch holes 18 in the material web section 17a, while the aligned punching tools 2, 2 'of the punching units 1a, 1b are used to punch holes 18' in the material web section 17b Aligned punching tools 2 ', 2 "of the punching units 1b, 1c, the perforations 18" are punched out in the material web section 17c. In this way, the individual areas a, d, g or b, e, h or c, f, i of the material web sections Edit 17a, 17b, 17c differently from one another.

It goes without saying that when in the Figure 8 The embodiment shown, the punching tools 2, 2 ', 2 "can also be aligned with one another in an arrangement other than that shown.

Are in the Figures 5 to 8 The embodiments shown are used in the punching tools 2, 2 ', 2 "punching strips 11 with differently designed punching dies 12, so punchings with different contours can be produced on the material web sections 17a, 17b, 17c.

It is also possible, in the same punching device, to use the Figures 5 and 6 explained mutual arrangement of the punching tools 2, 2 ', 2 "with the reference to the Figures 7 and 8 explained mutual arrangement of the punching tools 2, 2 ', 2 "to combine In such a solution, some of the punching tools 2, 2 ', 2 "are aligned with one another as described and some of the punching tools 2, 2', 2" are laterally offset from one another.

The hand of the Figures 5 to 8 The illustrated arrangements of the punchings (holes) 18, 18 '18 ", ie the punching images in the areas a - i of the material web 17, can be changed without a great deal of time. For example, the distances between the punchings 18, 18', 18" seen in the direction of movement A of the material web and / or the number of punchings 18, 18 ', 18 "per material web area a - i can be changed.

In all of the described exemplary embodiments, the material web 17 is moved forward in a manner not shown in detail, but known per se, at a constant or a changing speed v. The impression cylinder 5 of each punching unit 1 is driven at a peripheral speed which corresponds to the movement speed v of the material web 17. In each punching unit 1, the drive shaft 3 is driven independently of the impression cylinder 5. This means that the drive shaft 3 can be driven at a rotational speed which differs from the peripheral speed of the impression cylinder 5 and thus from the movement speed v of the material web 17. This enables the punchings to be made in the material web 17 to be adapted during operation, as will be done below with reference to FIG Figures 9 to 11 will be explained later.

The material web 17 provided with punchings 18 is then processed further and in doing so on per se known way cut or folded in the longitudinal and / or transverse direction.

With reference to the Figures 9 to 11 An essential aspect of the subject matter of the invention will now be described, namely the possibility of punching holes 18 in the material web 17, the mutual spacing of which does not correspond to the spacing of the punching dies 12 of the punching strip 11.

In the Fig. 9 is in one of the representation of the Fig. 4 A corresponding illustration shows a punching tool 2 with an unwound punching strip 11. The distance between the punching dies 12 of the punching sheet 12, which is uniform in the present case, is denoted by x. In the Fig. 9 a material web 17 is also shown in which holes 18, 18 ', 18 "are to be punched out, the mutual spacings y and y' of which deviate from the spacings x between the punching dies 12.

In the side view of the Fig. 10 , in which the punching tool 2 and the material web 17 with the attached or to be attached holes 18, 18 ', 18 "are shown only very schematically, the distances x and y between the cutting dies 12 and between the holes 18, 18', 18" registered. In this Fig. 10 the direction of rotation (target direction of rotation) of the punching tool 2 is denoted by B and its working diameter, which is determined by the cutting edges of the punching dies 12, is denoted by d. A working scope U of the punching tool 2 is determined by this cutting of the punching tools 2 or by the working diameter d. In the Fig. 10 is denoted by s an angle which defines a synchronous range. Each punch 12 is a such synchronous area s assigned. The angle indicated by r is called the dynamic range. Such a dynamic range is located between each die 12.

In order to punch the holes 18, 18 '18 "with unequal mutual distances y, y', the punching tool 2 is driven in the synchronous area s with a peripheral speed on the working circumference U which is the same as the movement speed v of the material web 17. In this synchronous area The holes 18, 18 'and 18 "are then punched. In the dynamic ranges r, the circumferential speed of the punching tool 2 can be varied and the distance y, y 'between the just punched hole 18 or 18' and the next hole 18 'or 18 "to be punched can be adjusted accordingly Fig. 11 explained.

In the Figures 11a to 11d Diagrams for various punching processes are shown, in each of which the angular velocity ω of the punching tool 2 is recorded as a function of the time t. These diagrams show the speed curves in two synchronous areas s, in each of which punching takes place, and in a dynamic area r lying in between. Above the diagrams, the punching tool 2 is shown schematically in its various respective rotational positions. That angular speed of the punching tool 2 is designated by ω1 which corresponds to a peripheral speed of the punching tool 2 which corresponds to the movement speed v of the material web 17. This means that the punching tools 12 run synchronously in the synchronous areas s with the material web 17. The situation is different in the dynamic range r, in which the angular speed ω of the punching tool 2 can be selected independently of the movement speed v of the material web 17, specifically adapted to the ratio of the distances y, y 'between the perforations 18, 18 ', 18 "at the distance x between the cutting dies 12.

In the diagram of the Figure 11a shows the time course of the angular speed ω of the punching tool 2 for the situation in which the distance y, y 'between two perforations 18, 18', 18 "is smaller than the distance x between the punching dies 12. In this case, the angular speed ω can be increased briefly in the dynamic range r, that is to say the punching tool 2 must be accelerated and then decelerated again to the angular velocity ω1.

If the distance y, y 'between two perforations 18, 18', 18 "is the same as the distance x between the cutting dies 12, the punching tool 2 continues to be driven in the dynamic range r at the angular speed ω1, as shown in diagram 11b. In this case, the punching tool 2 does not have to be accelerated or decelerated for a short time.

In the diagram of the Figure 11c shows the temporal course of the angular speed ω of the punching tool 2 for the situation in which the distance y, y 'between two holes 18, 18', 18 "is greater than the distance x between the punching dies 12. In this case, the angular speed ω are briefly reduced in the dynamic range r, that is, the punching tool 2 must decelerated and then accelerated again to the angular velocity ω1.

No perforation (punching) has to be made in an area of the material web 17 (see, for example, the material web areas b and d in Fig. 5 ), the punching tool 2 is briefly stopped after punching within the subsequent dynamic range r and accelerated again to the angular velocity ω1 before reaching the subsequent synchronous range s, as shown in the diagram Figure 11d is shown.

In certain cases, the direction of rotation of the punching tool 2 is reversed in the dynamic range r, i.e. the punching tool 2 is briefly rotated in the reverse direction.

As described, the distance y between two punchings 18, 18 ', 18 "can be influenced by a controlled acceleration or deceleration of the punching tool 2 in the dynamic range r. In this way, it is possible to determine distances y between the punchings 18, 18', 18" which do not correspond to the distances x between the punching dies 12 of the punching strip 11. Simply by changing the circumferential speed of the punching tool 2 in the dynamic range r, different punching images can be generated without mechanical adjustments being necessary.

So that the angular velocity ω of the punching tool 2 as based on the Fig. 11 can be changed if necessary in such a way that the punchings 18 are made in the material web 17 at the desired locations, the drive for the punching tool 2 must be controlled accordingly. In the Fig. 12 is a block diagram of a corresponding one Control device shown. In this Fig. 12 is in one of the Fig. 3 A punching unit 1 is shown in a corresponding illustration, of which only the components essential in connection with the control are provided with the corresponding reference numerals.

In this Fig. 12 the machine control is denoted by 19 and the drive control for driving the drive shaft 3 of the punching tool 2 is denoted by 20. The machine control 19 is connected to a sensor 21, in the present case a contrast sensor, which scans markings applied to the material web 17 and supplies corresponding scanning signals to the machine control 19. The machine control 19 is also connected to a control valve 22 of a removal device for removing the punched-out parts (diecuts) and to the drive control 20.

The information relating to the position of the punchings 18 to be made in the material web 17 and the movement speed v of the material web 17 is stored in the machine control 19. The angular velocity ω1 is derived from these quantities.

On the basis of the scanning signals received from the sensor 21 and the data stored in or determined in the machine control 19, the machine control 19 now determines the angular speed ω at which the punching tool 2 must be driven in the dynamic range r so that the punching (s) take place in the correct position. In addition, the machine control 19 controls the control valve 22 of the removal device at the correct point in time.

Another important aspect of the present invention is the following:
A punching unit 1 as shown in the Fig. 1 , the Fig. 2 or in the Figures 5 to 8 is shown, has at least one punching tool 2 which cooperates with a rotatably mounted, drivable counter-pressure cylinder 5 and which is arranged on a rotatably mounted, drivable drive shaft 3. This punching unit 1 also has a guide 6 which extends in the direction of the axis of rotation 3a of the drive shaft 3 and is separate from this drive shaft 3, along which the punching tool 2 is guided during adjustment and which extends parallel to the longitudinal axis 5a of the impression cylinder 5.

This special configuration of the punching unit 1, as defined in claim 15, has the advantage that the drive shaft 3 does not have to perform any guiding tasks and only has to be designed to transmit the drive power. This makes it possible to use lighter drive shafts 3 and thus the masses which, when the drive speed of the punching tools 2 change in the dynamic range r ( Fig. 10 ) have to be accelerated or decelerated to keep them as small as possible.

As described, a punching unit 1, 1 'or several punching units 1a, 1b, 1c arranged one behind the other are used, each punching unit having one or more punching tools 2, which are adjustable along their drive shaft 3 and can be locked in their respective working positions. This arrangement allows the punching units 1 to be rearranged in a simple manner and with relatively little expenditure of time in such a way that the arrangements of the parts to be punched out, that is to say the punching patterns, are different. By exchanging the punching strips 11, which can be done very easily is, both the punching patterns and the shape (contour) of the parts to be punched can be changed.

The driving of the punching tools 2 independently of the impression cylinder 5 expands the area of application of the punching unit 1, as shown in FIG Figures 9 to 11 has been explained.

In a further embodiment, the punching tool 2 or the punching tools 2, 2 ′ are mounted in such a way that they can be moved briefly in the direction away from the impression cylinder 5. This makes it possible to drive the punching tools 2, 2 ′ also in the synchronous range s at a peripheral speed which differs from the peripheral speed of the impression cylinder 5 or from the movement speed v of the material web 17. A brief lifting of a punching tool 2, 2 'from the impression cylinder 5 and the material web 17 makes it possible to deactivate certain punching dies 12 when the punching tool 2, 2' is rotated, i.e. not to bring them into contact with the material web 17 and thus to skip a punching 18 . This means that the sequence of the punchings 18, 18 ', 18 "made on the material web 17 in the direction of movement A of the material web 17 differs from the sequence of the punching dies 12 of the punching tool 2, 2' in its circumferential direction.

Claims (13)

1. An apparatus for punching moving material webs, having the following features:

   at least two punching units (1a, 1b),

   each punching unit (1a, 1b) has at least one punching tool (2), which interacts with a rotatably mounted back-pressure cylinder (5) that can be driven, which is arranged on a rotatably mounted drive shaft (3) that can be driven and of which the position can be adjusted in the direction of the longitudinal axis (3a) of the latter and which can be locked in various working positions,

   each punching tool (2) has a cylindrical base (10), on the periphery of which a punching strip (11) which is provided with at least one punching shape (12) is fixed such that it can be replaced,

   characterized in that

   the at least two punching units (1a, 1b) are arranged one after another in the direction of movement (A) of the material web (17) and that each punching unit (1a, 1b) has a guide (6) extending in the direction of the axis of rotation (3a) of the drive shaft (3), separate from the latter, along which guide (6) the punching tools (2) are guided during adjustment and which extends parallel to the longitudinal axis (5a) of the back-pressure cylinder (5).
2. The apparatus as claimed in claim 1, characterized in that each punching unit (1a, 1b) has two or more punching tools (2), of which the mutual spacing can be adjusted, arranged on the drive shaft (3).
3. The apparatus as claimed in claim 1 or 2, characterized in that, in the case of one punching tool (2) per punching unit (1a, 1b), the punching tool (2) of the one punching unit (1a) is offset with respect to the punching tool (2') of the other punching unit (1b), as seen in a direction running transversely with respect to the direction of movement (A) of the material web (17) or that, in the case of two or more punching tools (2) per punching unit (1a, 1b), at least one of the punching tools (2) of the one punching unit (1a) is offset with respect to one of the punching tools (2') of the other punching unit (1b), as seen in a direction running transversely with respect to the direction of movement (A) of the material web (17).
4. The apparatus as claimed in claim 1 or 2, characterized in that, in the case of one punching tool (2) per punching unit (1a, 1b), the punching tool (2) of the one punching unit (1a) is aligned with the punching tool (2') of the other punching unit (1b), as seen in the direction of movement (A) of the material web (17), or wherein, in the case of two or more punching tools (2) per punching unit (1a, 1b), at least one of the punching tools (2) of the one punching unit (1a) is aligned with one of the punching tools (2') of the other punching unit (1b), as seen in the direction of movement (A) of the material web (17) .
5. The apparatus as claimed in one of claims 1 to 4, characterized in that the punching tool (2) or at least some of the punching tools (2) of the one punching unit (1a) are used to process a first section (17a) of the material web (17) extending in the direction of movement (A) of the material web (17), and the punching tool (2') or at least some of the punching tools (2') of the other punching unit (1b) are used to process another, second section (17b) of the material web (17) likewise extending in the direction of movement (A) of the material web (17).
6. The apparatus as claimed in one of claims 1 to 4, characterized in that the punching tool (2) or at least some of the punching tools (2) of the one punching unit (1a) and the punching tool (2') or at least some of the punching tools (2') of the other punching unit (1b) are used to process the same section (17a or 17b) of the material web (17) extending in the direction of movement (A) of the material web (17).
7. The apparatus as claimed in one of claims 1 to 6, characterized in that the punching units (1a, 1b) extend substantially over the entire width of the material web (17).
8. The apparatus as claimed in one of claims 1 to 7, characterized in that the back-pressure cylinders (5) have a smooth surface, which is preferably hardened.
9. The apparatus as claimed in one of claims 1 to 8, characterized in that the back-pressure cylinders (5) can be driven with a peripheral speed which corresponds to the speed of movement (v) of the material web (17).
10. The apparatus as claimed in one of claims 1 to 9, characterized in that each punching tool (2, 2') is mounted in such a way, for example by using a radial coupling, that the distance between the punching tool (2, 2') and the back-pressure cylinder (5) can be set.
11. The apparatus as claimed in one of claims 1 to 10, characterized in that each punching tool (2) is provided with a device (27) operating with negative pressure for temporarily holding and subsequently discharging the parts punched out from the material web (17).
12. The apparatus as claimed in one of claims 1 to 10, characterized in that each punching tool (2) is assigned an output transport device (23) for transporting away the parts punched out of the material web (17), by means of which the parts punched out are separated out from the material web (17) by means of a jet (26) of a gaseous medium, preferably air, and are transported away.
13. The apparatus as claimed in claim 1, characterized in that the guide (6) is formed on the underside of a stationary guide beam (7) and extends over the entire working width of the punching unit (1).

Images