EP0418779A1 - Method for manufacture of workpieces by punching, in particular in a precision counter punching tool - Google Patents

Abstract

In a method for manufacture of burr-free workpieces by punching, in particular in a precision counterpunching tool, a punching strip (66) from which the workpiece is to be punched, is to be clamped between an upper (5) and a lower die plate (4) and an upper (48) and a lower (13) punch. Cutting is effected by interaction with an upper and a lower punch. During a stroke, the punching strip undergoes an initial cut in the shape of the workpiece, and the workpiece is punched out in the opposite direction during the same stroke. Burr-free workpieces are thereby produced. <IMAGE>

Description

The invention relates to a method for producing burr-free workpieces by cutting, in particular in a counter cutting tool, wherein a punched strip from which the workpiece is to be cut is clamped between an upper and a lower cutting plate and an upper and lower cutting punch and the cutting in cooperation with an upper and a lower cutting punch.

The cutting discussed here is a modification of a punching process. While a punching strip is subjected to a cutting punch on one side during punching, the punching strip is clamped between a cutting plate and a press plate, a cutting punch and a counterholder during fine cutting.

This significantly improves the quality of the cut surface of the workpiece.

Furthermore, so-called counter-fine cutting or counter-fine stamping is also known, in which the punched strip is clamped between two cutting plates and two cutting punches. Then a cutting punch cuts the workpiece against the pressure of the other cutting punch, the pressure of this cutting cutting punch outweighing that of the other cutting punch.

After cutting, the pressure build-up is reversed, i.e. the pressure on the other cutting punch outweighs the pressure that acted on the first cutting punch. This cuts the workpiece from the other side.

As a result, the pressure build-up is reversed, i.e. the pressure of the first cutting punch outweighs the pressure of the other cutting punch, as a result of which the workpiece is finally cut out.

Such a method is described for example in DE-PS 27 27 445. A disadvantage of this method is that a separate work station is provided in the fineblanking device for each work step, which slows down and increases the cost of the entire work process.

It has also been found to be particularly disadvantageous that the device or elements of the device have to be stopped and their movement reversed as a result of the multiple pressure reversal. This means not only a considerable expenditure of energy, but also the development of your own device, which is especially suitable for counter fine cutting. In addition, there is a slowdown in the entire work process.

The inventor has set itself the goal of eliminating these disadvantages of the known counter fine cutting or counter punching and of developing a method which can be used in an already existing fine blanking press and in particular avoids a change of movement within this fine blanking press during a working stroke.

To achieve this object, the punched strip is cut into the contour of the workpiece during a lifting operation and the workpiece is cut out in the opposite direction during the same lifting operation, thereby producing burr-free workpieces.

A major advantage of the present method is that there is no longer any change of motion in the fineblanking press during a lifting operation. The entire counter fine cutting process requires only one work station and only a single lifting process.

This lifting process is preferably carried out with a drive device of the fineblanking press which moves a cutting plate and a cutting punch together with a lifting force. For the sake of simplicity, the basic drive device of the fineblanking press itself is used here. A fineblanking press usually consists of a table and a ram. The table is often placed over the plunger so that the plunger is raised towards the table. The actual counter cutting tools, such as cutting punches and cutting inserts, are each on the table or on the ram. In the present case, a separate device should preferably be assigned to each cutting plate as well as each cutting punch, which acts on both the cutting punch and each cutting plate with a certain compressive force, regardless of the actual lifting force of the drive device of the fineblanking press, for example the press ram. There are five forces. A suitable hydraulic system with a hydraulic pressure medium is preferably provided for building up the pressure forces, since this hydraulic pressure medium can be regulated and switched off or on at the correct time. This ensures the highest precision and production performance. Mechanical springs could also be used, but these have a force-displacement characteristic and cannot be regulated or can only be regulated in a complicated manner. However, other possibilities of building up pressure should also be encompassed by the present inventive concept.

Since the actual counter-fine cutting takes place during the lifting process, the lifting force should be selected to be greater than the sum of the compressive forces which act on the cutting plates or the cutting punches and carry out the actual counter-fine cutting process during the lifting process. In addition, there is a certain cutting force for cutting the workpiece, this cutting force being the product of the cutting line length, the material thickness and the specific shear strength of the material.

Contrary to the counter fine cutting mentioned in the prior art, in the present case the workpiece is actually cut by a cutting punch in cooperation with the other cutting punch, while the cutting is carried out by the further movement of the cutting plates along the cutting punch during the stroke.

In a first operation, a cutting plate and a cutting punch are moved by the press hydraulics, ie the lifting force, against the other cutting punch or the other cutting plate until the punched strip is clamped. For example, the pressure force of the cutting punch that has been lifted outweighs that of the other punch that is located in the other cutting plate. On the other hand, however, the pressure force which acts on the other cutting plate outweighs that which acts on the cutting plate to be lifted. As the lifting process continues, the cutting punch, which is subjected to a lower force, is therefore pushed back as far as it will go, while the raised cutting plate remains standing.

The pushing back takes place by an amount that corresponds to a fraction of the thickness of the workpiece. This cuts the workpiece. However, since the pushed-back cutting punch now stops as a result of the stop, this cutting process is also stopped, i.e. the cutting stamp stops. At this moment, the raised insert, which has so far been stopped by the pressure of the counter-cutting insert, has reached a stop, so that the lifting force of the fineblanking press now outweighs the counter-holding force of the other insert. During the further lifting process, the lead frame is now taken along and passed both cutting punches until the workpiece is cut out. The cutting process is finished, all pressure forces on the cutting plates or cutting punches are switched off. The lifting force is also switched off, so that the plunger, on which the one insert and the one die are located, is lowered. The cut workpiece is located in this insert, while the lead frame on the other insert remains around the die there.

In the end position, one cutting punch then ejects the workpiece, while the opposite cutting plate strips the lead frame from its cutting punch. The punched strip can now be moved further in the device and a next lifting process or a counter fine cutting process can be started.

In a corresponding device for producing burr-free workpieces by counter-fine cutting from a punched strip or the like, which is clamped between an upper and a lower cutting plate, the cutting takes place in cooperation with an upper and a lower cutting punch. In this case, a machine drive with a lifting force is provided for a unit consisting of cutting plate and cutting punch and both this cutting plate and this cutting punch, as well as the other cutting plate and the other cutting punch, are acted upon by compressive forces.

The tool structure works with practically the same upper and lower parts. Both cutting plates and both cutting punches, which together effect the cutting process, can be identical. The tool structure corresponds to an overall cut in which the workpiece is manufactured in one press stroke. The cutting process itself takes place when the material is clamped at all times. In the present case, it is preferably a so-called 5-way machine.

The plunger of the fineblanking press which carries out the stroke advantageously works at a controlled, adjustable speed in order to take account of the respective materials and desired partial shapes. At the same time, performing the lifting process by means of the ram with adjustable speed means a longer service life of the active cutting elements, which bring about the actual cutting process. The plunger can work from top to bottom as well as from bottom to top.

At rest, i.e. in the starting position before a new stroke, a cutting punch maintains a distance from a stationary insert ring or the like, which can be changed to zero under the pressure of the other cutting punch. This distance is only a fraction of the thickness of the workpiece, so that it remains ensured that the cutting punch cuts the workpiece only by the amount of the distance. This fraction depends on the strength or the properties of the material and its thickness.

A corresponding distance is also provided on the other tool part. The opposite insert maintains this distance. As soon as this cutting plate has changed the distance to zero, its pressure outweighs that of the counter-holding cutting plate, so that cutting of the workpiece by the one cutting punch stops. For this reason, both distances should preferably be the same.

The lifting process of the ram of the fineblanking press is ended when the cutting plates with the clamped-in lead frame have traveled a distance corresponding to the dimension from the depth of the gate of the workpiece and the thickness of the workpiece. After covering this path during the stroke of the ram, the workpiece is cut out of the punched strip.

A corresponding annular piston in a pressure chamber should preferably be assigned to each cutting plate and each punch, the desired pressure force being built up in the respective pressure chamber.

The compressive force which acts on one cutting punch is smaller than the compressive force acting on the other cutting punch. Conversely, the compressive force which acts on one insert is less than that which acts on the other insert. The force ratio is of course always plus the cutting force.

The present inventive concept naturally also includes the possibility that the workpiece is first cut through the cutting plates by a corresponding control of the pressure forces acting on the cutting plates and corresponding stops and cut out by the cutting punches during the further lifting process.

It should also be mentioned that the arrangement of the ring pistons and the entire structure of the tool make the ring pistons work as displacers, which inevitably do their job and therefore no switching is required during cutting. This is a production-safe priority control that works without interference. Such a principle also allows stroke sequences of well over 100 strokes per minute.

A normal 3-way fineblanking press is used, which is provided with the additional two compressive forces and thus becomes a 5-way fineblanking press.

This press can therefore be used for normal fineblanking as well as for counterblanking.

The press thus forms a flexible manufacturing system.

• Fig. 1 zwei unterschiedliche Längsschnitte durch eine Feinschneidpresse;
• Fig. 2 eine schematische Darstellung eines erfin­dungsgemäßen Verfahrensablaufes zum Konter­feinschneiden in verschiedenen Arbeitsstufen a-e;
• Fig. 3 vergrößert dargestellte, zu Figur 2 gehörende Ausschnitte aus einem Konterschneidwerkzeug im Bereich der Werkstückbearbeitung;
• Fig. 4 eine Draufsicht auf ein Werkzeugteil;
• Fig. 5 eine Draufsicht auf ein weiteres Werkzeugteil, mit dem Teile mit Innenformen hergestellt werden;
• Fig. 6 einen teilweise dargestellten Querschnitt durch ein im Normalstanzverfahren bearbeitetes Werkstück;
• Fig. 7 einen teilweise dargestellten Querschnitt durch ein im Feinschneidverfahren bearbeitetes Werkstück;
• Fig. 8 einen vergrößert dargestellten Querschnitt durch ein im Konterfeinschneidverfahren bear­beitetes Werkstück.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

• 1 shows two different longitudinal sections through a fineblanking press;
• 2 shows a schematic representation of a process sequence according to the invention for counter-fine cutting in different working stages ae;
• 3 shows enlarged sections of a counter cutting tool belonging to FIG. 2 in the area of workpiece machining;
• 4 shows a plan view of a tool part;
• 5 shows a plan view of a further tool part, with which parts with internal shapes are produced;
• 6 shows a partially shown cross section through a workpiece processed in the normal punching method;
• 7 shows a partially illustrated cross section through a workpiece machined using the fineblanking method;
• 8 shows an enlarged cross section through a workpiece machined in the counter fine cutting method.

According to FIG. 1, a fineblanking press for counter-fineblanking has a machine ram plate 1 which is guided in a ram guide 2. The plunger plate 1 in the plunger guide 2 can be raised in the x direction.

A guide plate 3 is connected to the plunger plate 1 and receives the cutting plate 4 as the lower tool part. This cutting plate 4 is associated with an additional cutting plate 5 as an upper tool part, which is located on an upper guide plate 6. This upper guide plate 6 is connected to a base plate 7 which hangs on a table top 8. The attachment is effected via a screw bolt 9 which engages in T-nuts which are fixed in a corresponding groove 11.

Comparable to the base plate 7, a lower base plate 12 is fixed on the tappet plate 1, the fixing also taking place via screw bolts 9a which engage in corresponding sliding blocks 10a guided in a groove 11a.

A cutting punch 13 is guided in the lower cutting plate 4. This cutting punch 13 is seated on a punch guide 14, which in turn is supported by a punch support plate 17. This platen 17 is finally seated on a pressure pin 19 which is connected to an annular piston 20. A pressure F2 can apply a force F2 to this annular piston 20, the corresponding force F2 being built up hydraulically.

A corresponding oil inflow or outflow is identified by 22.

The annular piston 20 is penetrated by a support pin 23 which rests on the tappet plate 1 in the pressure chamber 21 and supports an insert ring 24 on the other. The pressure pin 19 is also guided in this insert ring 24 and an annular cylinder 25 is also formed, in which an annular piston 26 is seated. Here, too, this annular piston 26 forms, together with the annular cylinder 25, a pressure chamber 27 which is supplied with a hydraulic medium via an inflow or outflow line 28.

By means of the annular piston 26, a pressure pin 29 can be moved, which in turn passes through the pressure plate 18. For this purpose, a force F4 acts in the pressure chamber 27. This force F4 is transmitted via the pressure pin 29 to a further pressure pin 30 which engages a pressure disc 31. This thrust washer 31 supports the guide plate 3 and maintains a distance A in the position shown from another thrust washer 32. This distance A can be changed against the force F4 during the cutting process. It becomes zero. Distance shoulder screws 34 are also provided between the guide plate 3 and the base plate 12.

In the guide plate 3, a pressure plate 35 is also embedded, which surrounds the cutting punch 13. Furthermore, on this pressure plate 35 there is an enclosure 36 for the cutting plate 4, the cutting plate 4 being penetrated by a pressure pin 38.

On the right, a guide plate 39 for a finished workpiece adjoins the border 36, while the border 36 is acted upon by a nozzle 40 of a blow nozzle block 41 with compressed air.

The guide plate 3 and the guide plate 6 are connected to one another via guide columns 42 for positional adjustment. The guide columns 42 penetrate guide bushes 43 in the upper base plate 7, guide bushes 44 in the guide plate 3 and guide bushes 45 in the lower base plate 12.

The upper cutting plate 5 is assigned to the lower cutting plate 4 in the upper guide plate 6, as is the case 36 with an upper case 46, to which an upper pressure plate 47 adjoins. Cutting plate 5 and pressure plate 47 are penetrated by a cutting punch 48, which in turn is assigned to the cutting punch 13. Analogously to the pressure pin 38, a pressure pin 49 is also provided next to the cutting punch 48, which is supported on the other against a punch holding plate 50 and on the other hand projects beyond the cutting punch 48 by a measure of the thickness d of a punched strip 66. This stamp holding plate 50 lies against a stamp guide 51 which is arranged below a stamp support plate 52. This stamp platen 52 maintains with a shoulder 53 a distance B from an upper insert ring 54, which is inserted into the table top 8. This distance B can be changed against the pressure of a piston 55, which slides in a pressure chamber 56 within the insert ring 54. A pressure F3 is built up or reduced in the pressure chamber 56 by supplying or discharging a hydraulic medium via the line 57.

Corresponding to the guide plate 3, the upper guide plate 6 is also attacked by a pressure pin 58, which is connected to the upper guide plate 6 via a pressure plate 59, while it is attacked by an annular piston 60 with the interposition of a pin 70. When pressure is applied to the upper guide plate 6, a distance C between the pressure plate 59 and a further pressure plate 61 lying against the base plate 4 can thereby be reduced. This takes place against the pressure in a pressure chamber 62, in which a hydraulic medium can be introduced via line 63, so that a force F1 can act here. A support bolt 64 also passes through the annular piston 60. A guide for a punched strip 66 shown in greater detail in FIGS. 2 and 3 is indicated at 65.

Since both cutting plates and cutting punches are subject to wear and are therefore reground, these elements, such as, for example, the pressure bolts 38 and 49, are lined with tuning plates (not shown).

The method according to the invention will now be described in more detail with reference to FIGS. 2 and 3. In a continuous ram stroke according to FIG. 2a), the ram plate 1 is raised so that the punching strip 66 is clamped between the lower cutting plate 4 and the upper cutting plate 5 and the cutting punches 13 and 48. This start-up takes place through the hydraulics of the fineblanking press, which are not shown in detail. A lifting force F acts here, which is greater than the pressing force F1 + force F2 + force F3 + force F4 + cutting force F _s , which indicates the force which is required to cut a workpiece from the punching strip 66. In addition, force F2 acts in pressure chamber 21 and force F4 in pressure chamber 27.

The plunger plate 1 then continues with a force F, namely by the amount of the distance B, as indicated in Figure 2b). The pressure F2 remains in the pressure chamber 21, this pressure F2 outweighing the cutting force F _s and the force F3 in the pressure chamber 56. This means that the cutting punch 48 runs back by the dimension B until the punch support plate 52 comes into contact with the insert ring 54. A corresponding amount of hydraulic medium runs out of the pressure chamber 56 via the line 57.

Furthermore, the cutting plate 4 is moved relative to the lower base plate 12, the ring piston 26 running back in the ring cylinder 25 and the pressure force F1 overcoming the force F4. This continues until the pressure disc 31 comes to rest against the pressure disc 32 and the distance A is eliminated. In contrast, the pressure pin 29 is now at a corresponding distance A from the lower surface of the lower base plate 12. The punching strip 66 is cut through this step.

The plunger plate 1 continues to run, as is indicated in FIG. 2c) for the lower base plate 12. The cutting plate 4 is taken along, while the lower cutting punch 13 remains. This occurs because the upper cutting punch 48 or its punch support plate 52 abuts the insert ring 54, so that the upper cutting punch 48 cannot retreat any further. The upper cutting plate 5, on the other hand, is pushed back against the force F1 by a dimension S, which allows the punched strip 66 to be cut through.

The force F1 is greater than the cutting force F _s and the force F4. The latter is canceled at the moment when the lower cutting plate 4 has come to a standstill as a result of the guide plate 3 resting against the lower base plate 12.

This movement has the effect that the punching strip 66, which has previously been cut upward by dimension A, is cut in the opposite direction all the way down into the cutting plate 4 by the cutting punch 48. This is done against the pressure F2, which acts in the pressure chamber 21 for the cutting punch 13.

By means of the pressure bolts 38 and 49, a distance between the cutting punches 13 and 48 is maintained, namely by the dimension of the thickness d of the punched strip 66.

In this position of the tool, the counter fine cutting process is finished. The forces F1, F2, F3 and F4 acting in the individual pressure chambers are switched off and the plunger plate 1 runs back. According to FIG. 2d), it can be seen that the cut workpiece 67 is seated in the cutting plate 4, while the remaining punching strip 66 hangs on the upper cutting punch 48.

In the position of the counter-cutting tool shown in FIG. 2e), the pressure forces F1, F2, F3 and F4 are now built up in the individual pressure chambers, so that the cutting punch 48 can again take up its distance B from the insert ring 54.

At the same time, the upper cutting plate is moved downwards by the pressure force F1 by the dimension C, which is higher than the distance B. The cutting plate 5 thus slides further downward relative to the cutting punch 48, as a result of which the punching strip 66 is stripped off.

The pressure build-up F4 also creates the distance A between the cutting plate 4 or its guide plate 3 and the lower base plate 12. This is done relative to the lower punch 13 so that it acts as an ejector for the workpiece 67. This workpiece 67 is blown out of the blow nozzle 40.

An advantage of the method according to the invention can be seen particularly in FIG. 3. While in a normal punching method according to FIG. 6 there is a punched edge pull-in 68 and on the other hand a burr formation 69, the formation of which is only softened in the normal fineblanking according to FIG. In other words, workpieces 67 are manufactured without any punch burr 69.

During normal punching, a punched edge indentation and a burr are created on the workpiece. In between there is a smooth cut surface as well as a breaking or tearing surface. With fineblanking, a smooth cut surface is created over almost the entire thickness of the workpiece, as is indicated by the vertical strips. Counter-fine cutting, on the other hand, has a symmetrical influence on the cutting surface, as can be seen in FIG. There is an edge indentation on both sides and the formation of smooth cut surfaces from both surfaces. There are no longer any burrs.

4 shows, for example, the production of a needle-shaped workpiece 67a.

FIG. 5 shows the production of a part with two inner shapes, in this case round holes, which can also have any other shape, part 67 _b .

Figure 4 shows in the upper half a bottom view of the upper part of the counter-cutting tool, in particular with the upper guide plate 6 and the upper base plate 7. The lower half of Figure 4 represents a plan view of the lower part of the counter-cutting tool, in particular with the guide plate 3 and of the base plate 12. The guide columns 42 and the blowing nozzle block 41 with nozzle 40 are also indicated.

In this embodiment, a needle is to be produced, but of course other shapes of workpieces can also be produced in the simplest way, such as, for example, B. in Figure 5 a part 67 _b with two holes.

The tool frame with base plate 12 and guide plate 3 or 6 and 7 can have any shape. The cutting plates 4 and 5 can also be divided, in one piece, round, angular or consist of other shapes. The same also applies to the mounts 36 and 46. The mounts 36 and 46 can be received in a recess, as shown, or can be placed on the corresponding guide plates 3 and 6.

The pressure bolts 58, 70 and 29, 30 should always be arranged around the cutting punches 13 and 48, respectively, so that optically optimal support remains guaranteed.

Instead of the screw bolts 9 interacting with the sliding blocks 10, a quick-change device can also be provided, as is shown, for example, in European Patent 0 201 456.

Any material can be cut, be it steel, tempering steel, hardenable, rustproof steel, aluminum or its alloys, copper, but also plastics, e.g. fiber reinforced plastics. It can be worked with or without ring spikes. The shape of the parts is arbitrary with or without internal shapes. The material thicknesses are 0.2 to 8.0 mm and above. All of this is encompassed by the present inventive concept.

Claims (22)

1. A method for producing burr-free workpieces by cutting, in particular in a counter cutting tool, wherein a punching strip from which the workpiece is to be cut is clamped between an upper and a lower cutting plate and an upper and lower cutting punch and the cutting in cooperation with one upper and lower cutting punches are made,
characterized,
that the punched strip is cut in the contour of the workpiece during a lifting operation and the workpiece is cut out in the opposite direction during the same lifting operation, thereby producing burr-free workpieces. 2. The method according to claim 1, characterized in that the lifting process is carried out with a drive device of a fine blanking press, which moves a cutting plate and a cutting punch together with a lifting force. 3. The method according to claim 1 or 2, characterized in that separate controllable compressive forces act on each cutting insert as well as on each cutting punch. 4. The method according to claim 3, characterized in that the lifting force is selected to be greater than the sum of the compressive forces which act on the cutting plates or the cutting punch plus a cutting force for cutting the workpiece. 5. The method according to claim 4, characterized in that a pressure force acting on a cutting punch is greater than the pressure force acting on the other cutting punch plus the cutting force. 6. The method according to claim 5, characterized in that the pressure force acting on the one insert is greater than the pressure force acting on the other insert plus the cutting force. 7. The method according to at least one of claims 1 to 6, characterized in that the cutting force moves a cutting plate and a cutting punch to the other cutting plate and to the other cutting punch, then the one cutting punch in the stroke direction by the other cutting punch by a fraction of the amount The thickness of the workpiece is displaced up to a stop and then the punched strip is fed through the cutting plates in the stroke direction. 8. The method according to at least one of claims 1 to 6, characterized in that a cutting plate and a punch moves to the other cutting plate and to the other cutting punch by the lifting force, then the one cutting plate in the lifting direction by the other cutting plate by a fraction of the size The thickness of the workpiece is displaced up to a stop and then the workpiece is cut out in the stroke direction by tracking a cutting punch. 9. Apparatus for producing burr-free workpieces by counter-fine cutting from a punching strip, circuit board, coil material or the like, which is clamped between an upper and a lower cutting plate and an upper and lower cutting punch, the cutting interacting with an upper and a lower one Cutting punch takes place, characterized in that a machine drive with a lifting force (F) is provided for a unit consisting of cutting plate (4) and cutting punch (13) and both this cutting plate (4) and this cutting punch (13) as well as the other cutting plate ( 5) and the other cutting punch (48) are subjected to compressive forces (F2, F4 or F1, F3). 10. The device according to claim 9, characterized in that a punch support plate (52) adjoins the cutting punch (48), which in the rest position maintains a variable distance (B) from a stationary insert ring (54) or the like. 11. The device according to claim 10, characterized in that the distance (B) corresponds to a fraction of the thickness (d) of the workpiece (67). 12. Device according to one of claims 9 to 11, characterized in that the cutting plate (4) from a thrust washer (32) or the like. Stop maintains a distance (A) which can be changed towards zero under pressure on the cutting plate (4) is. 13. The apparatus according to claim 12, characterized in that the distance (A) corresponds to the distance (B). 14. The device according to at least one of claims 9 to 13, characterized in that the cutting plate (5) from a thrust washer (61) or the like. Maintains a distance (C) which can be changed under pressure on the cutting plate (4). 15. The apparatus according to claim 14, characterized in that the distance (C) is greater than the thickness (d) of the workpiece (67) plus the distance (B). 16. The device according to at least one of claims 9 to 15, characterized in that the cutting plate (4) via at least one pressure bolt (30, 29) is connected to an annular piston (26) which delimits a pressure chamber (27) in which the Pressure force (F4) is effective. 17. The device according to at least one of claims 9 to 16, characterized in that the cutting punch (13) is connected to an annular piston (20) which delimits a pressure chamber (21) in which the pressure force (F2) is effective. 18. The device according to at least one of claims 9 to 17, characterized in that the cutting plate (5) via pressure bolts (58) is connected to an annular piston (60) which delimits a pressure chamber (62) in which the pressure force (F1) is effective. 19. The device according to at least one of claims 9 to 18, characterized in that the cutting punch (48) is connected to a piston (55) which delimits a pressure chamber (56) in which the pressure force (F3) is effective. 20. The apparatus according to claim 19, characterized in that the compressive force (F2) is greater than the compressive force (F3) plus a cutting force (F _s ). 21. The apparatus according to claim 19 or 20, characterized in that the pressure force (F1) is greater than the pressure force (F4) plus a cutting force (F _s ). 22. Device according to one of claims 19 to 21, characterized in that the lifting force (F) is greater than the sum of the compressive forces (F1 + F2 + F3 + F4) and the cutting force (F _s ).

Images