EP0616861B2 - Press with table- and feeding system - Google Patents

Description

The invention relates to a Press with one Table system and feed system according to the preamble of the claim 1.

Such systems are used to make panels, for example Steel or aluminum sheet, positioned to feed a press, which a predetermined number of blanks cut out the board. With the help of suitable feed means, which one via gripping or other feed means Grasp the blackboard, the blackboard is gradually moved through Press moved through and during a standstill one Subjected to punching step. The feed is usually done along two orthogonal axes because it is cheaper Material utilization an offset division on the Blackboard is chosen. In this context is from the US-A-4 382 395 discloses a panel system which a feed carriage has two gripping tongs, which grasp the board on the back edge and gradually advance into the machine tool. The feed is coupled to the movement of the machine tool in such a way that the feed takes place at a time when the tool is not closed and therefore outside the Working level. At the end of a work cycle the feed carriage travels to an exit or sheet transfer station back, in which he grabs the next board. This is carried by a loading carriage from a table alignment station in the correct position in the table takeover position in which the panel is located immediately before the Tool is located. Here the loading carriage moves under the feeder around the metal sheet in the takeover position. The drive for the Loading carriage is usually designed so that the Always load the sled into the same slab transfer position brings regardless of their size and the die cut.

From the last feed step of a preceding table until the following table is handed over in the feed device inevitably passes a certain amount of time is significantly longer than the press cycle time.

DE-A-34 37 642 is already a table system became known that works without unproductive change times. The known system requires two separate feed devices each on one side of the board attacking collets, which are used alternately. However, such a system is relatively complex.

In the unpublished EP-A-539669 is already proposed the Gripping means of the feed device at the rear end of a Grip the panel on opposite sides to the side to let. In addition, the transfer position corresponds to that Position of the sheet in which a first punching stroke is carried out becomes. In other words, during the first punch stroke, in which the tablet is also temporarily stationary is transferred from a first feed device or a loading carriage in a second feed device, with the board for the remaining punching steps is moved forward. Becomes a single line of tools used in the press, the gripping means of the second feed device along two orthogonal Axes to make the necessary according to the division of the board To be able to make punchings.

If a two-row arrangement of the tools is used, as it is known per se (DE-A-38 41 683), needs second feed device the panels only along one To move the axis through the press. It is known, arrange the tools of the two rows offset from each other, by, for example, the tools of the rear Row arranged in the gaps of the tools in the front row are.

In order to save material, the aim is to bridge the so-called residual grids as narrow as possible. On the other hand, it must be avoided that punching or punching out happens. Especially with two-row tool arrangements care must therefore be taken to ensure that the Sheets are fed precisely. This can be done through suitable controls, for example numerical controls to reach.

From the generic DE-A-38 41 683 is known, the feed with pliers up to half of the board, but then on one To transfer roller feed. The roll feed takes over the already punched out grid and pulls on it. This Handover and create the unreliable basis of the grid Great accuracy problems, especially with thin sheet metal.

The invention is therefore based on the object to create a press with a sheet feed and feed system that works without empty strokes of the press, precise alignment allowed a precise feed guaranteed and a lattice with minimal web width enables without Punching and punching on the rear and front edge.

This object is achieved through the features of the patent claim 1 solved.

The press according to the invention is based on one of DE-A-3841683 known press from the two seen in the feed direction rows of tools arranged one behind the other are. The tools can be in the feed direction to each other aligned or gapped. The system according to the invention uses two feed devices, the first of which is a panel from an alignment station in which the board is precisely oriented or is aligned to reference coordinates. Essential to the invention is that the second feed device is the panel only takes over after the press has already had two or more Has performed punching strokes. This way, without idle strokes be driven. However, this means that the plates be pushed forward to the press in such a way that the last stamping step of a board coincides with that first punching step of the next sheet.

For tool arrangements where the first row of tools has a tool less than that in the feed direction second, the board - precisely aligned - during the entire punching process in pliers on the massive, yet not punched out side of the board.

With the same number of tools in both rows, the last one Feed path of the sheet from a suitable feed means, e.g. a roller feed. Since it is but only the last step can do all the necessary Corrections are made beforehand. So that can the last panel position by mechanical means in Tool instead of e.g. unsafe roller feed To be defined.

The pliers can be mounted on rigid mounts and from Spindles are moved so that a high number of cycles is obtained becomes. A clamping edge is not necessary because the feed tongs, who hold the board at the end of processing, are arranged outside.

Immediately after the transfer, the first feed device can return to the starting position by one next table in the alignment station. While of the return stroke, the gripping means are sunk by one Collision with the one subsequently entering the alignment station Avoid blackboard. The path that the gripping means the first feed device on the return stroke need hardly be more than the length of a board. With the help of conventional drive means do this in a sufficiently short time.

Because the second gripping means of the second feed device only grasp the panel after the first feed device the board already a few punching steps in the The press has advanced the return stroke of the second gripping means relatively short. This also makes a complete Punching operation guaranteed without idle strokes.

The drives from the first and second feed device are identified by a numerical Control controlled. The numerical control enables a precise movement in time and space, so that even with an extremely unfavorable ratio of Sheet size and number of blanks an idle stroke is avoided.

As is known, the sheets are made with the help of guillotine shears cut from the strip material. This naturally results Tolerances in terms of panel length and angularity the cut edges. In this context, strikes an embodiment of the invention that at least two Sensors are provided which are transverse to the feed direction or axis have a predetermined distance from each other and grasp the front and back edges of a panel and give an appropriate signal.

With the help of the sensors the deviation of the front or trailing edge determined from the transverse axis. she will in determining the correction factor for the numerical Control can be used as described above. Is the deviation from the exact transverse axis is too large, so that punching out is unavoidable, a stop signal can be generated become. Alternatively, a punch stroke can also be suspended to avoid punching out faulty die cuts.

When driving up the table on the way from the alignment station for the first punching, the front edge of the board passes both sensors. The switch-on edges of both sensors are in relation to the current position of the feed device brought. This position is with a Resolution of 0.01 mm by the measuring system of the NC control detectable. This means that the further feed can be made as required correct the measurement result.

Are the two switch-on edges of the sensors for one If the edge of the board is brought into a dimensional relationship, the unevenness the edge of the board can be determined.

With two rows of tools for the press comes the first Punching a sheet only the first row of tools in Feed direction for use. It has to be secured, that during this punching process there is a bridge to the outer contour remains, but at the same time the board must not already protrude into the cutting area of the second row of tools. The angularity must therefore be below a fixed one predetermined value remain to punch or punch to prevent safely. If not, either stopped, or the first critical die cut is made skipped.

In addition, the leading edge can be related overall brought the way to the tool become. So it is possible regardless of the absolute Length of the board the first punching position while driving adjust there so that no punching or punching occurs. Adjusting the first cutting position of the board in accordance with the response of the sensors via the The path still to be covered serves at a given distance the range of tools and thus the given web width of the Residual lattice, the upper limit for the angularity to be able to set as high as possible. Even with smaller ones Web width of e.g. 0.8 mm should only cover a few panels the limit comes to lie. The existing space between the tool rows are therefore used optimally. Would the panels in a fixed, non-customizable first control position a higher value for the web width be provided.

The sensors can be transverse to the feed direction or axis have a predetermined distance from each other and the front one and capture the rear edge of a board and a corresponding one Give signal. The distance between the sensors is preferably only a little smaller than the width of the panels, to get a high measuring accuracy. In the numerical Control is a setpoint for the length of the board saved. In numerical control, the an actual value for the panel length is calculated for both sensor signals. By detecting the front or the rear Edge and the numerical control values determine the exact length of the board. For this are however, very sensitive sensors are required. Therefore proposed according to an embodiment of the invention that they are formed by laser light barriers. The on the actual length determined as described above a table is compared with the target value, and from the The difference between the setpoint and actual value becomes a correction value for calculate the following feed steps.

The position of the feed device in which the leading edge is detected, can be specified in relation to a fixed Value to be set as a result of the previous one Alignment of the panel expected for normal panel length becomes. Any deviation from this value shows one Deviation from the nominal board length. Within the geometric Possibilities of the tool arrangement can now the web widths within the panel to correct the overall panel length be used. The determination of Panel length in the above manner assumes that the panel in the alignment station with respect to its rear and a side edge with respect to reference coordinates is exactly aligned.

Record during the subsequent processing of the board the same sensors in the same way the rear panel edge. The same evaluation is carried out as for the front one Edge, but using the switch-off edges. The The angle is checked and the actual distance of the The trailing edge of the board for the tool is detected and adapted the subsequent punching positions or feed steps used.

If a length measurement is made before the first punching step, the control for the first feed device must be a Undergo correction if a changed length by the Sensors determined and a correction factor calculated has been. If a second feed device is used, which the panel from a first feed device takes over while already in the press, there is a similar change in the feed cut lengths, if a table length deviating from the nominal value is determined has been punched out on the rear Be avoided.

A stop signal can also be generated if one from the target / actual value comparison of the table length large deviation results, which is certainly too faulty Would lead to die cuts.

The second gripping means are particularly short the second feeder back when after an embodiment of the invention, the board in the transfer position at the back of the board on opposite Capture sides laterally.

Before grasping a board by the gripping means of the first The feed device must reference the table with reference coordinates be arranged exactly. This happens in the Alignment station. The board must naturally be replaced by a suitable one Funds are brought into the alignment station. A third feed device is used for this purpose Sheet is conveyed from a loading station to the alignment station. According to one embodiment of the invention, the third Feed device two parallel by separate numerical controlled third actuators Conveyor belts with one driver each. The drivers are arranged so that one behind each one blackboard and the other in front of a blackboard. The in each case the front driver, which is a plate to the alignment station has first been engaged with the front Brought edge of the next board for what he may even have to be moved back again. It promotes then together with the rear driver, which is on the rear Edge of the next board attacks, the board in the alignment station. Only when this process ends the front driver returns with the circulation of the conveyor belt back and is now the rear driver for Transport of another board towards the alignment station. The separately driven conveyors therefore allow one fast and exact feeding of the sheet to the alignment station, the leading driver as a stop acts in the braking phase.

Alternatively, the third feed device can be numerical have driven feed rollers that the panel of capture below and above. The pairs of rollers are preferred driven by a single servo motor. A first one The pair of rollers is preferably less than one panel length behind the so-called table separation and brakes remove the tablet and hand it over numerically to a second Controlled pair of rollers, which the plate in the alignment station promoted. It brings the board to a standstill and is then preferably moved apart by a few millimeters, so as not to hinder the alignment process.

Fig. 1

zeigt schematisch teilweise im Schnitt die Draufsicht auf eine Presse mit einem Tafelanlage- und Vorschubsystem nach einem Ausführungsbeispiel der Erfindung.

Fig. 2

zeigt eine ähnliche Darstellung wie Fig. 2, jedoch in einer anderen Betriebsphase.

Fig. 3

zeigt eine Draufsicht auf eine Einzelheit der Vorrichtung nach Fig. 1.

Fig. 4

zeigt eine Draufsicht auf eine abgewandelte Ausführungsform einer Vorlagestation der Presse nach der Erfindung.

Fig. 5

zeigt eine Seitenansicht der Station nach Fig. 4 in Richtung Pfeil 5.

The invention is explained in more detail below with reference to drawings.

Fig. 1

shows schematically partially in section the top view of a press with a table system and feed system according to an embodiment of the invention.

Fig. 2

shows a representation similar to FIG. 2, but in a different operating phase.

Fig. 3

shows a plan view of a detail of the device of FIG. 1st

Fig. 4

shows a plan view of a modified embodiment of a feed station of the press according to the invention.

Fig. 5

shows a side view of the station of FIG. 4 in the direction of arrow 5.

A press 10 is indicated in FIGS. 1 and 2, whose tools are arranged in two rows 12 and 14. The front row 12 seen in the feed direction 16 has five tools, while the back row 14 four tools has that in the gaps of the front tools 12 are arranged. As is known, the tools actuated simultaneously with a single punch stroke to the to punch out front panel 18 shown in Fig. 1, thereby there are circular die cuts and a so-called Residual grid 20. A first feed device 22 has two gripping tongs 24, 26 with which the scrolled Table 18 is detected at the rear edge. The pliers 24, 26 are arranged on an arm of a carriage 30 which along guides 32 with the aid of a first adjustment drive 34 is adjustable in the feed direction 16. The Gripping tongs 24, 26 can also be adjusted in height, so that on the return stroke they have a subsequent table like the panel 36, do not disturb.

A second feed device 38 has a carriage 40 on, along guides 42 also in the feed direction 16 can be adjusted. The feed drive is used for this 44. The carriage 40 supports two arms 46, 48 (In Fig. 1 only the arm 46 is shown for reasons of clarity. For this is the first feed device in Fig. 2 not shown with the exception of the gripping tongs 24, 26). On the arms 46, 48 there are second gripping tongs 50, 52 attached, which the panels laterally at the rear end to capture. From a presentation device, not shown the plates are on two parallel sliding surfaces 56, 58 placed, which extend to the press 10. In Figs. 1 and 2 there is a panel 60 in a feed station 70. Extend between the sliding surfaces 56, 58 two parallel narrow conveyor belts 62, 64 that pass through a third drive, not shown, independently of one another are drivable. Each conveyor belt 62, 64 has one Driver 66, 68 on. One recognizes that a driver or Cam 66 engages the rear edge of a panel 60, while a front driver or cam 68 is located on or in front of the front edge of panel 60. With With the help of the carriers 66, 68, the table 60 is removed from the presentation station 70, conveyed to an alignment station 72, in which is the board 36. The alignment station 72 is drawn again separately in FIG. 3 to indicate that alignment means (not shown) the panel 36 against two side stops 74, 76 and a rear stop 78 lay. Such alignment means are generally known.

In Fig. 1, laser light barriers 80, 82 are in the front Area of the positioning station 72 and 84, 86 in the rear Area indicated. The light barrier pairs 80, 82 and 84, 86 have a predetermined distance from each other. The Light barriers of a pair 80, 82 and 84, 86 are on one extending perpendicular to the feed axis 16 Transverse axis. However, it should be mentioned that a pair of light barriers alone, e.g. 80, 82 all necessary Functions fulfilled.

Finally, it should be mentioned that the drives 34, 44 and the drive for the conveyor belts 62, 64 of one numerical control, not shown, can be controlled.

The press described works as follows.

The presentation device, not shown, places a board 60 on the surfaces 56, 58 in the reference station, and the Carrier 66 of the conveyor belt 64 promotes the table 60 Alignment station 72, possibly progressing with the Feed the board 36 from the alignment station towards Press 10. The alignment takes place in the alignment station 72 the table 36 with the aid of the alignment means, not shown along two orthogonal axes. The grippers 24, 26 of the first feed device 22, which during the return stroke of the carriage 30 are lowered to advance a Do not disturb the board to the positioning station, grasp the Panel 36 at the rear end, as dash-dotted lines in FIG. 1 shown. During this time, the second feed device is pushing 38 with the help of the grippers 50, 52 Plate 18 by the press 10. The feed of the plates 36, 18 and the feed devices 22 and 38 are on the numerical control coordinated so that the last die cut the sheet 18 coincides with the first punching of the sheet 36, as shown in Fig. 2. The last stamping of the panel 18 is done by the row of tools 12 and the first punching of the new sheet 36 tool row 14. The transition therefore takes place without an idle stroke of the press 10.

As soon as the last punch stroke for the sheet 18 has been carried out has been released, the grippers 50, 52 and Carriage 40 can move back to a starting position, as shown in Fig. 1. The grippers 24, 26 the first feed device 22 take over the feed the board 36 by the press 10 for a number of punching steps, e.g. two or more. Therefore the grippers need 50, 52 just a relatively short before the takeover To make the way back, as can be seen from the comparison of the figures 1 and 2 results. The advance of the table 18 for the first Part of the punching steps is carried out with the solid ones Lines drawn grippers 24, 26. Is the default When the number of punching steps is reached, the transition takes place on the second feed device 38 by the Open gripping tongs 24, 26 and gripping tongs 50, 52 conclude. This transition takes place during a punch stroke, i.e. immediately during tool engagement with the blackboard, since the blackboard has a fixed position occupies, their situation therefore does not change. Subsequently the second feed device 38 guides the rest Feed steps out until the empty skeleton runs through an ejection device, not shown, for example a driven roller pair can be removed.

As soon as the grippers 24, 26 have opened, they can after lowering below the feed plane into the in Fig. 1st Move back in dash-dotted position to the to record the following table 36 and advance it to the press 10.

The feed of a board 60 from the feed station into the Alignment station 22, which with the help of a rear Nockens 66, 68 takes place, is relatively precise and takes place smoothly as the front driver 68, 66 can act as a stop or brake, so that a quiet Transition to the alignment station 72 can take place.

If a board 36 using the first feed device 22 from the alignment station 72 towards the press is moved, the front edge of the panel 36 crosses the two laser light barriers 80, 82. From their signals or the times of the signals in comparison to the location, the front edge due to the numerically controlled The length of the table should have feeds determine and thus the deviation from the target length. The feed can now be done by means of a correction value Getting corrected. Alternatively, the length of the board also by grasping the trailing edge of panel 36 through the light barriers 84, 86 are determined. About the numerical Control the path can be determined exactly between crossing the front light barriers 80, 82 and crossing the rear light barriers 84, 86 is. Since the distance between the light barriers 80, 82 on the one hand and 84, 86 on the other hand, can be also in this way the length of the panel 36 or its deviation from the target length.

The actual length of the determined in the numerical control Table 36 is compared to a stored target length. For example, if panel 36 is slightly shorter than the target length, the numerical control over the feed through the first feed device 22 ensure that the plate 36 is pushed sufficiently far into the press, that in the first stamping step, as shown in Fig. 2, a web remains at the front edge of the board 36, otherwise faulty die cuts will be produced. Therefore calculates the numerical control from the deviation a correction value from the target and actual length of the sheet the feed path or the length of the feed steps accordingly to correct so faulty die cuts cannot be generated. The same applies to the rest Feeding the front panel 18 through the second feed device 38. If the board is too short, on a faulty punching out at the rear end of the board 18 occur. By correcting the feed accordingly Feed device 38 between the punching steps made sure that a web is also on the rear edge stop. For example, this can happen that during that made by the feed device 38 Feed steps each is a little shorter than originally programmed, which also bridges between the die cuts become a bit narrower. Overall, however thereby "gained" a certain length, which for the last punching step ensures that die cuts or Punching on the rear edge does not occur. Become only the front light barriers 80, 82 are used by grasping the rear edge of the board Determine the length of the sheet or that for the remaining punching steps remaining table length, um then a feed correction in the manner described above to be able to make.

Characterized in that two sensors each along a transverse axis 80, 82 or 84, 86 are provided, can also Angularity of the front and back edges of the panels be determined. If the edge is not at right angles to the feed axis 16 is also a corresponding Correction in the way described above performed. If the angularity and also the length measurement there is an excessive deviation from the target values, can also generate a stop signal for the press become. Alternatively, a punching step can be skipped to make an appropriate compensation can.

As you can see, you can work with just two sensors, e.g. close to the tools, which is natural is less complex than the use of four sensors.

In the presentation station 70a (FIGS. 4 and 5) the system points a frame 90 in which a shaft transverse to the feed direction is rotatably mounted. Sitting on the shaft 92 Distance rotatably two feed rollers 94, 96, and the shaft 92 is driven by a servo motor 98 by a Pinion 100 of the servo motor 98 with a pinion 102 on the Shaft 92 via a toothed belt 104 in drive connection stands. Lever arms 106, 108 are rotatable at one end the shaft 92 articulated. At the other end they hold trunnions 110, 112, the feed rollers 114, 116 rotatably. With the feed rollers 94, 96 are pinions 118, 120 connected, and with the feed rollers 114, 116 are pinions 122, 124 connected. The sprockets are about a suitable one Driving means in connection, so that when the Feed rollers 94, 96 also the feed rollers 114, 116 are driven. As can be seen in particular from FIG. 5, the arms 106, 108 are connected to a lever arm 126, an adjustment cylinder 128 is articulated at the other end thereof is.

The rollers 94, 96 and 114, 116 act with upper rollers together, two of which are shown at 130, 132 in FIG. 5 are. They are on appropriate fixed brackets 134, 136 rotatably mounted. By actuating the adjusting cylinder 128 can the rollers 114, 116 a little after be pivoted below, as indicated by arrow 138.

The first roller pairs seen in the feed direction are less than the length of a panel 60a behind the panel separation arranged as in Fig. 1 on the right edge of the picture is indicated. Through the numerical drive of the feed rollers 94, 96, 114, 116 via the servo motor 98 Plate 60a braked and driven to the second synchronously Pass pair of rollers 114, 116, which the table 60th to the alignment station, designated 72 in Fig. 1 is. In the alignment station, the plate that is in Fig. 4 is designated 36a, brought to a standstill. The adjusting cylinder 128 is then actuated in order to the rollers 114, 116 a little from the upper rollers 130 too remove to align the panel 36a is not disabled.

Claims (10)

1. A punch (10) having a plurality of tools (12, 14) including a plate positioning and feeding system comprising:

   a) a positioning station disposed upstream of the punch (10) and including positioning means for positioning a plate (36) with respect to a pair of orthogonal axes (74, 76, 78)

   b) a first feed device (22) including first gripping means (24, 26) adapted to be displaced by a first feed drive means (34) at least in the direction of the feed axis (16) and arranged to grip a plate (36) in the positioning station (72) in a rear position and to feed the plate towards the punch (10)

   c) a second feed device (38) including gripping means (50, 52) adapted to be displaced by a second feed drive means (44) along the feed axis (16) and arranged to grip a plate in a rear position and to advance the plate towards the punch,

   d) the punch (10) including two rows of punching tools (12, 14), with the rows being spaced in feed direction of the plates (18, 36, 60)
   characterized by the following features:

   e) the first feed device (22) is arranged to advance the plates to a transfer position which is downstream of the positioning station (72)

   f) the second feed device (38) is arranged to grip the plate in the transfer position

   g) the transfer position is arranged to correspond to the position of the plates (18, 36) during a punching stroke of the punch (10) after the punch (10) has performed at least one preceding punching stroke on a plate

   h) first and second feed devices (22, 38) co-operate so that the leading row of punching tools (12) performs the last punching stroke with respect to a first plate (18) at the same time when the trailing row of punching tools (14) performs the first punching stroke with respect to the following plate (36).

   i) second gripping means (50, 52) are arranged to laterally grip each plate (18) from opposite sides at the trailing end thereof when the plate (18) is in the transfer position.
2. The punch of claim 1, characterized in that a loading station (70) is provided upstream of the positioning station (72), and a third feed device is provided to advance the plate (60) into the positioning station (72).
3. The punch of claim 2, characterized in that the third feed device includes a pair of parallel conveyor means (62, 64) driven by separate numerically controlled third drive means and each including a drive member (66, 68) which are arranged such that one of the drive members is disposed upstream of a plate and the other is disposed downstream of a plate (60).
4. The punch of claim 3, characterized in that the conveyor means (62) of the leading one (68) of the drive members (66, 68) is controlled so that it engages the leading edge of a plate (60) when the plate (60) is advanced toward the positioning station (72).
5. The punch of claim 2, characterized in that the third feed device includes feed rollers (94, 96, 114, 116, 130, 132) spaced along the feed direction, with the feed rollers engaging a plate (60a, 36a) from upper and lower sides and are driven in unison by a numerically controlled drive (98), the spacing of the feed rollers in the feed direction being smaller than the length of a plate (60, 36a), and the leading feed rollers (114, 116) being displaceable out of the feed path of the plate (60a, 36a) and being coupled to an actuating device (128)
6. The punch of claim 5, characterized in that the lower of the leading feed rollers (114, 116) are supported by arms (106, 108) which are pivotally mounted to a frame (90) and are engaged by at least one actuating cylinder (128).
7. The punch of one of the claims 1 to 6, characterized in that at least one pair of sensors (80, 82, 84, 86) being spaced from each other transverse to the feed direction for a predetermined amount and arranged to sense the leading and the trailing edges of a plate (36) so as to provide corresponding signals, and a numerical control for said first and said second drive means (34, 44) arranged to determine an actual value of the plate length from said sensor signals and the feed data of the respective feed device is stored in said numerical control and to compare said actual value with a desired value stored in the numerical control and to compute a correction value from the difference between the desired and actual values, the correction value being used to correct the remaining feed of the respective plate by the first drive means (34) and the feed of the plate by the second drive means (44).
8. The punch of claim 7, characterized in that at least a pair of sensors (80, 82, 84, 86) is provided in spaced relationship to each other along a transverse axis which extends perpendicularly with respect to the feed direction (16), which sensors are arranged to sense the leading and trailing edges of the plate (36) in order to provide signals to be used in the numerical control for determining any deviation of the edges of the respective plate (36) from the transverse axis (angularity).
9. The punch of claim 7 or 8, characterized in that the numerical control is arranged to provide a stop signal when the difference between the desired and actual values or the deviation of the plate edges from the transverse axis exceed a predetermined value.
10. The punch of one of the claims 7 to 9, characterized in that the sensors (80, 82, 84, 86) comprise laser light sensors.

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