EP0546392B1 - Cutting blade and apparatus therewith - Google Patents

Description

The invention relates to a punching knife for cutting through non-metallic parts, in particular single-layer or multi-layer, plastic-containing parts, with a flat knife body and with teeth that are connected along a foot line to the knife body and the tips of which protrude alternately in the knife stroke direction .

As far as here and in the following we speak of punches, punching knives or punching devices, it goes without saying that this does not mean a limitation to punching in the actual sense, but that it is to be understood in the broadest sense as a severing by means of linear stroke movements.

Punch knives are often provided with a straight row of teeth of the same size, the tips of which also lie on a straight line (see, for example, FR-A-2 122 144). Such punch knives generally work satisfactorily. Depending on the workpieces to be machined, the energy required when cutting through is different and can be relatively high. In order to reduce the compressive forces, it is already known, in particular when cutting from plastic or predominantly from Plastic existing parts to heat the knife or at least its cutting edge, for example by electrical means (US-A-4 215 607).

With the punch knife described at the beginning, which is known from GB-A-551 569, the required cutting pressure can also be reduced because not all knife teeth hit the workpiece at the same time during the working stroke. In this known punching knife, alternately large teeth with more protruding tips and small teeth with less protruding tips are provided, which are connected to the knife body along a common straight foot line.

This known punching knife is used to perforate paper or cardboard either by means of the large teeth, by means of different dimensions of the working stroke of the punching knife, to perforate more strongly and at smaller intervals by means of the large and small teeth, or to cut them completely. In the latter case, however, all the large teeth and then all the small teeth are attacked on the workpiece at the same time. Accordingly, half of the teeth hit at the same time, which only leads to a comparatively small reduction in the pressure forces to be applied.

The invention is based on the object of providing measures which make it possible to work with an even lower expenditure of energy, that is to say with even lower forces and with even lower pressures than previously.

To achieve this object, the invention provides that the foot line of the teeth extends in a wave shape and that a there is a cutting contour with wave crests and wave troughs running in the knife plane and comprising the tooth tips, with adjacent wave crests and wave troughs having at least three teeth.

Such a knife has proven itself for severing single or multi-layer parts made of plastic, textiles, fabrics or the like.

Due to the wave crests and the wave troughs, only a few teeth of the cutting edge cut through the workpiece at the same time. The teeth of a wave crest take effect one after the other and not all teeth are in mesh at the same time. This is linked to a significant reduction in energy consumption.

In a further development of the invention it is also provided that all wave crests or wave troughs have the same height in relation to a common level line. However, the wave crests and / or the wave troughs can preferably also be of different heights, the cutting edge then expediently comprising groups of wave crests or wave troughs of the same type.

In a further development of the invention it is also provided that the cutting or punching knife has a great height (transverse to its length) or an extremely great height in comparison to conventional knives. It is thereby achieved that flat, three-dimensionally shaped bodies are punched at their edges or in the area of openings in the silhouette can be. It is therefore often not necessary to arrange several punching knives in different planes and skewed to each other, for example to process any room curve. Rather, in many cases a punch knife that can be moved in a single direction or only a few punch knives that can be moved in a single direction are sufficient in comparison with the prior art.

The punching device comprises a machine frame with at least one drive and with at least one punching knife according to claims 1 to 16 as well as with at least one hold-down device for the workpiece and with at least one counter tool for the punching knife or knives. According to the invention, the device in the counter tool has a cutting gap and the lower part can be moved towards and away from the workpiece by the drive of the punching knife and together with the punching knife and can be moved relative to the punching knife. The punch knife can therefore perform extremely large strokes when working in silhouette.

Further features of the invention emerge from dependent claims in connection with the description and the drawing.

Fig. 1:

abgebrochene Ansichten von Stanzmessern mit jeweils Wellenbergen gleicher Höhe und jeweils Wellentälern gleicher Höhe sowie mit Zähnen und mit jeweils rücken-paralleler bzw. mit wellenberg- und wellental- paraleller Fase;

Fig. 2:

Ansichten wie in Fig. 1, jedoch von Stanzmessern mit Wellenbergen gleicher Höhe und mit Wellentälern unterschiedlicher Höhe;

Fig. 3:

Ansichten wie in den Figuren 1 und 2, jedoch von Stanzmessern mit Wellenbergen unterschiedlicher Höhe und mit Wellentälern gleicher Höhe;

Fig. 4:

Ansichten wie in den Figuren 1 - 3, jedoch von Stanzmessern mit Wellenbergen unterschiedlicher Höhe und mit Wellentälern unterschiedlicher Höhe;

Fig. 5:

einen Schnitt längs der Linie V - V in Fig. 1;

Fig. 6:

einen Schnitt wie in Fig. 5 von einem abgewandelten Ausführungsbeispiel;

Fig. 7:

einen Schnitt wie in Fig. 5 von einer weiteren Ausführungsform;

Fig. 8:

zum Teil im Schnitt eine Seitenansicht von wesentlichen Teilen der Vorrichtung zum Stanzen;

Fig. 9:

zum Teil im Schnitt eine Stirnansicht der Vorrichtung gemäß Fig. 8;

Fig.1o:

eine Ansicht wie in Fig. 8 von einer abgewandelten Ausführungsform;

Fig.11:

eine Stirnansicht eines mit dem Stanzmesser zusammen arbeitenden Gegenwerkzeuges;

Fig.12:

eine Draufsicht auf das Gegenwerkzeug gemäß Fig. 11;

Fig.13:

eine Stirnansicht des Gegenwerkzeuges gemäß Fig. 11 in einer anderen Arbeitsposition;

Fig.14:

eine Draufsicht auf das Gegenwerkzeug in der Arbeitsposition gemäß Fig. 13;

Fig.15:

einen Schnitt durch wesentliche Teile einer letzten Ausführungsform einer Vorrichtung zum Durchtrennen und

Fig.16:

einen Ansicht eines der Messer gemäß den Figuren 1 -4, jedoch mit von seinem Rücken ausgehenden Ausnehmungen.

The invention is described below with reference to exemplary embodiments which are illustrated in the drawing. Show:

Fig. 1:

broken views of punching knives, each with wave crests of the same height and wave troughs of the same height, as well as with teeth, each with a back parallel or with a wave crest and wave trough parallel bevel;

Fig. 2:

Views as in Figure 1, but of punching knives with wave crests of the same height and with troughs of different heights;

Fig. 3:

Views as in Figures 1 and 2, but of punch knives with wave crests of different heights and troughs of the same height;

Fig. 4:

Views as in Figures 1-3, but of punch knives with wave crests of different heights and troughs of different heights;

Fig. 5:

a section along the line V - V in Fig. 1;

Fig. 6:

a section as in Figure 5 of a modified embodiment.

Fig. 7:

a section as in Figure 5 of a further embodiment.

Fig. 8:

partly in section a side view of essential parts of the punching device;

Fig. 9:

partly in section an end view of the device according to FIG. 8;

Fig.1o:

a view as in Figure 8 of a modified embodiment.

Fig. 11:

an end view of a counter tool working together with the punch knife;

Fig. 12:

a plan view of the counter tool according to FIG. 11;

Fig. 13:

an end view of the counter tool of FIG 11 in a different working position.

Fig. 14:

a plan view of the counter tool in the working position shown in FIG. 13;

Fig. 15:

a section through essential parts of a last embodiment of a device for severing and

Fig. 16:

a view of one of the knives according to Figures 1-4, but with recesses extending from its back.

A separating and punching knife 1 according to FIG. 1 consists of a flat, elongated knife body 2 in the manner of a piece of strip steel with teeth 3 along the cutting contour 4, which has wave crests 5 and wave troughs 6. The wave crests 5 and wave troughs 6 merge continuously into one another. In addition to a wave crest 5 with teeth 3, a wave trough 6 with teeth 3 is arranged. Wave crests 5 and wave troughs 6 are thus adjacent to one another.

The teeth 3 are each directed in the direction of the stroke movement of the separating and punching knife 1. They extend according to the embodiment shown in FIG. 1 not primarily perpendicular to the cutting contour, but in the direction of the lifting movement.

The teeth 3 have tips 7, cutting edges 8 and 9 and side flanks 10, 11 and 12. Between the respective tooth 3 and the knife body 2 with a full cross section there is also a transition region 13 in the form of a chamfer 14, which either has a boundary line 15 parallel to the back 16 of the separating and punching knife 1 or a boundary line 17 as shown on the left in FIG. 1 parallel to the contour of the wave crests 5 and the wave troughs 6 as shown on the right in FIG. 1.

1, all wave crests 5 are of the same height and extend to a common level line 18. The same applies to the wave troughs 6, which are also of the same height or extend to a common level line 19. The level lines 18 and 19 run parallel to the back 16 of the separating and punching knife 1, so that the distance of all the crests 5 and all the troughs 6 from the back 16 of the separating or punching knife 1 is the same.

Fig. 2 shows a modified cutting and punching knife 1a, in which the same parts have the same reference numbers, but carry the letter index a.

The separating and punching knife 1a differs from the knife 1 only in that all wave crests 5a are of the same height and extend to the same level line 18a, while the wave troughs 6a are of different heights and extend to different level lines 19a, 2oa, or 21a extend. All level lines 18a to 21a in turn run parallel to the back 16a of the separating and punching knife 1a.

According to the embodiment of a separating and punching knife 1b shown in FIG. 3, the wave crests 5b are of different heights and extend to different level lines 18b and 22b, while all wave troughs 6b are of the same height and extend to a common level line 19b.

Fig. 4 finally shows a fourth separating and punching knife 1c, which differs from the knives described first in that the wave crests 5c and the wave troughs 6c are of different heights and up to different mountain level lines 18c and 22c and to extend to different valley level lines 19c and 2oc.

For all separating and punching knives 1 to 1c it applies that the level lines each run parallel to the back 16c and that the tooth shapes and their position or direction are the same and that either parallel bevels 14 or parallel bevels 23, 23a, 23b or 23c are provided.

The punching knife 1 can have back-parallel bevels 14 on both sides 24 and 25 according to FIG. 5.

6, in addition to the two chamfers 14d, a modified punching knife 1d can also be provided in regions on its one side 25d with a groove 26d which extends from the tip 7d of the teeth 3d to the boundary line 15d on one side 25d .

A punch knife 1 e according to FIG. 7 has a chamfer 14e only on one side 25 e. The other side 24 e is flat and the tips 7e of the teeth 3e lie in the plane of the side 24e. Fillets 27e, which extend beyond the boundary line 15e of the chamfer 14e, are also provided.

The exemplary embodiments according to FIGS. 6 and 7 are only intended to show that a separating or punching knife in addition to the different shapes of wave crests 5 and wave troughs 6 according to FIGS. 1 to 4 can also be modified in a further manner.

The cutting contour 4a, 4b and 4c in the case of the punching knives 1a, 1b and 1c each consist of groups of the same type of wave crests and wave troughs of different heights. Not all wave crests or wave troughs are at different levels, but two, three, four or more mountain and / or valley level lines are provided, over which the wave crests and wave troughs are distributed. Within these level lines, the various wave crests and troughs are repeated in groups.

As shown in FIGS. 1-4 and also the sectional views according to FIGS. 5-7, the punching knives 1 - 1e have a very large knife height (FIG. 1) in comparison to their material thickness s (FIG. 5). The knife height can be 60 - 90 millimeters and more with a material thickness s of 3 - 6 millimeters. The knife height H can therefore be far greater than that of conventional knives.

Finally, each punching knife 1 to 1e can also be assigned a heating device 28, as is indicated by dashed lines in FIG. 1. This heating device 28 can either be an electrically inductive heating device or other radiators. Such a heating device 28 is used in connection with each of the punching knives 1 to 1e if this is expedient in the individual case.

A device 31 for punching using punching knives 1 to 1e is, according to the exemplary embodiment shown in FIGS. 8 and 9, a structural unit 33 consisting of drive 32 and bearing and guide parts as well as the punching knife 1. The structural unit 33 comprises an angle piece 34 of sufficient length , on one leg 35 bearing parts 36 with guide bushings 37, for example are screwed on. The guide bushes 37 serve for the parallel guidance of movable parts 38 which carry the punching knife 1 at one end 39 and are connected to the drive 32 at their other end 40. The movable parts 38 are e.g. rods or bolts that are round in cross-section and sufficiently long, depending on the respective application.

In the embodiment shown in FIGS. 8 and 9, the drive 32 is a hose drive, which comprises a stationary pressure plate 41, a movable pressure plate 42 and at least one hose 43 serving as a drive element. The stationary pressure plate 41 is the second leg of the angle piece 34. The hose 43 lies against it and is supported in each case. The movable pressure plate 42 is at the free ends 4o of the movably mounted, rod-shaped or bolt-shaped parts 38, for example screwed on and thus guided parallel to the leg 35 of the angle piece 34. The hose 43 for stroke movements of the punching knife 1 is supplied with compressed air or emptied again via a connecting piece 44. The hose 43 is closed at its ends with the aid of screw clamps 45. The return stroke is expediently carried out with the aid of a reset element 46, which can be a rubber buffer or a spring.

Guide pieces 47 are finally arranged on the stationary pressure plate 41 and extend parallel to the leg 35 of the angle piece 34.

At their free ends 39, the rod or. bolt-shaped parts 38 not only the punch knife 1, but also at least one hold-down device 51 in each case.

The hold-down devices 51 are moved by the drive 32 of the punching knife 1 together with the latter toward and away from a workpiece not shown in FIGS. 8 and 9 and can also be moved relative to the punching knife 1. Each hold-down device 51 has a double function, since on the one hand it serves as a hold-down device for the workpiece when it is cut and on the other hand it is also able to guide the punching knife 1.

Each hold-down device 51 is movably mounted on the bolt-shaped or rod-shaped part 38 that carries it, relative to the punching knife 1, and for this purpose is arranged on its lower, free end 39 (FIG. 9) with the aid of a bore 52 of a guide piece 53 serving as a sliding guide. According to the exemplary embodiment shown in the figures, the guide piece 53 of each hold-down device 51 has a rectangular outer contour. Legs 54 extending or screwed to the cutting edge are arranged or screwed to the guide piece 53 on both sides of the punching knife and each carry a hold-down foot 55 or 56 on both sides of the punching knife 1. In many cases, although not shown in the figures, a can also be used or several hold-down feet can only be arranged on one side of the punching knife 1.

The hold-down feet 55, 56 can be angular in cross-section and consist of two legs, one leg 57 respectively resting on the workpiece and serving as a pressure piece. Both hold-down feet 55, 56 can be angular strips in cross-section, which can extend from one rod-shaped or bolt-shaped part 38 to the next and also beyond. These strips, which serve as hold-down feet 55, 56, are fastened to the free ends of the legs 54 in a suitable manner and for this purpose e.g. welded on.

On their mutually facing, second legs 58, guide strips 59 are arranged which lie loosely directly on the punching knife 1 and also have a guiding function for the punching knife 1 during the severing. The hold-down feet 55, 56 are provided with an adhesive part 6o on their underside. This adhesive part 6o can be emery cloth and / or Velcro and / or are other projections and depressions, with the help of which the workpiece clamped firmly between the holding-down device 51 and the counter tool 61 is securely and immovably fixed.

The hold-down devices 51 are guided with the aid of the guide pieces 53 along the rod or. bolt-shaped parts 38 are movable or displaceable against the force of springs 62. The springs 62 are supported on adjustable stops 62a (FIG. 9). The hold-down devices 51 with their hold-down feet 55, 56 protrude on both sides over the cutting contour 4 (FIG. 8) of the punching knife 1 and hit the workpiece in front of the punching knife 1 during a working stroke. The workpiece is thereby first clamped and held between the hold-down feet 55 and 56 and the counter tool 61. The holding force corresponds to the pressing force of the springs 62.

Only during the further working stroke of the rod-shaped or bolt-shaped parts 38, which carry the punch knife 1 at their free end, do their teeth penetrate and cut through the workpiece one after the other in accordance with the selected shaft contour. The hold-down device (s) 51 maintain their position on the counter tool 61.

The entire assembly 33 is fastened with the aid of holding parts 63 to a machine frame, not shown in the figures, in a manner not of interest here.

The counter tool 61 has a cutting gap 64 into which the punching knife 1 works. This cutting gap 64 or knife gap can also be a groove or a cutting channel.

According to the exemplary embodiment shown in FIGS. 8 and 9 and in the other figures and in particular in FIGS. 11 to 14, the counter tool 61 consists of a base plate 65 on which supports 66 are arranged at a distance from one another. The supports 66 also serve as spacers and create a sufficient depth for the cutting gap 64.

At their end facing away from the base plate 65, the supports 66 carry cutting bars 67 running on both sides of the cutting gap 64 or parallel to these. These cutting bars 67 are preferably arranged on the supports 66 such that they can be detached and fastened in such a way that their position relative to the direction of movement of the Stamping knife 1 are adjustable or adjustable. For this purpose, the cutting strips 67 are fastened to flat end faces of the supports 66 with the aid of screws 68, the screws penetrating elongated holes 69 in the cutting strips 67. change from a position according to FIGS. 11 and 12 into a position according to the cutting gap 64 a in FIGS. 13 and 14. An adaptation to the exact position of the punch knife 1 is therefore easily possible.

The cutting strips 67 also each carry an adhesive part 7o corresponding to the adhesive parts 6o on the hold-down feet 55 of the hold-down device 51 along their edges on the cutting gap side.

The adhesive parts 7o each overlap with an edge strip 71 on the cutting gap side of the corresponding edges of the Cutting strips 67. In order to give the edge strips 71 sufficient strength, the adhesive parts 7o not only consist of emery cloth, Velcro or the like, but also from a load-bearing metal sheet with sufficient material thickness.

The adhesive parts 6o on the hold-down device 51 and the adhesive parts 7o on the counter tool 61 are effectively facing each other and not only hold the workpiece between them after the hold-down device 51 has been placed on the workpiece, but they also stabilize the hold-down device 51 in its position after it hits the workpiece . As a result, the hold-down device 51 can perform its double function and also guide the punching knife 1 directly on the workpiece during its further stroke movement. For this purpose, the guide strips 59 are finally arranged as low as possible on the hold-down holder 51 and extend to the level of its adhesive parts 6o. (Fig. 9).

The exemplary embodiment shown in FIG. 1o is a device 81 for punching, the punching knife stroke of which is considerably greater than that of the device 31, which is shown in FIGS. 8 and 9. While the workpiece can still be relatively flat there, the device 31 serves to cut through a strongly curved or three-dimensionally deformed workpiece.

The device 81 is also a structural unit and has a hose drive 83 which, for example, comprises a plurality of hoses 84 as drive elements. The possible stroke is therefore correspondingly larger and all parts which otherwise correspond to those of the device 31 according to FIGS. 8 and 9 are adapted to the larger stroke. This also includes a larger knife height H (Fig. 1o), which results not least from the contour of the workpiece to be cut in the silhouette. The punching knife 1 must cut through all the parts of the workpiece in spite of its strong curvature in the case of linear movement. The stroke, the knife height H, the length of the rod or. bolt-shaped parts 38, the length of the legs 54 of the hold-down device 51 and also the height of the supports 66 of the counter tool 61 are longer and larger in the device 81 than in the device 31.

Furthermore, the contours of the hold-down feet 85 of the hold-down 51 and the contours of the cutting strips 86 of the counter tool 61 in the device 81 are adapted to the contour of the workpiece (FIG. 10). In this case, a lower mold 87, which is at least partially made of plastic, can also be used, which is adapted to the contour of the workpiece and integrated in the counter tool 61 or in the lower tool. The subform 87 is then e.g. expediently a plastic shell.

Finally, it goes without saying that, in the case of the arrangement according to FIG. 10, the punch knife 1 must penetrate into the cutting gap 64 in an extremely drift manner in order to be able to cut through a strongly curved workpiece at all points. The punching knife 1 penetrates at least partially with the major part of its entire height into the cutting gap 64, its back with the screws serving for fastening then being located in the region of the guide bar 59 provided with recesses there.

Instead of a hose drive, a drive with piston-cylinder devices (not shown in the figures) can also be provided.

A last exemplary embodiment of a device 121 for punching is shown in section in FIG. 15. It consists of a punch tool 122 and a counter tool 123, which has a cutting gap 124 for the punch knife 125.

The cutting edge 126 of the punching knife 125 is provided with teeth and has wave crests and wave troughs in accordance with the exemplary embodiments described above.

The punch knife 125 is supported with its back 127 on a e.g. pressure plate 128 made of wood and is e.g. fixed with the help of holding parts 129, 13o. Rubber strips 131 serving as hold-down devices and wipers flank the punch knife 125.

In order to form the cutting gap 126 on the counter tool 123, supports 133, which carry cutting strips 134, are in turn fixed on a base plate 132. The cutting strips 134 are fastened to an end face of the supports 133 with the aid of screws 135 and thereby engage through elongated holes 136 in the cutting strips 134. The elongated holes 136 extend transversely to the exemplary embodiment shown in FIGS. 8 and 9 and 11-14 Punching knife 125. The position and width of the cutting gap 124 can therefore be changed by loosening the screws 135 and adapted to the exact position of the punching knife 125.

The rubber strips 131 serving as hold-down devices and wipers are dimensioned with regard to their dimensions so that they first strike the workpiece 137 and fix it to the counter-holder 123 before the cutting edge 126 of the punching knife 125 becomes effective during a working stroke.

According to the pressure plate 128 on the upper punch 122, the counter tool 123 also has a e.g. pressure plate 138 made of wood. To cut the workpiece 137, the device 121 with the workpiece 137 is e.g. pushed through the nip of a roller device, not shown in Fig. 15.

To cut thermoplastic materials, it is customary and known to heat the cutting or punching knife or to heat it to more or less precisely defined temperatures. This can be done with the help of one or more rod heaters or the punch knife is heated electrically inductively. A separating and punching knife 1 intended for such a purpose is shown in FIG.

The punching knife 1 according to FIG. 16 again consists of a flat, elongated knife body 2 with teeth 3 along the cutting contour 4, which has wave crests 5 and wave troughs 6 according to the exemplary embodiments described first. A chamfer 14 with a boundary line 15 parallel to the back 16 of the punching knife and with a boundary line 15a parallel to the shaft contour as shown on the left in FIG. 16 or a chamfer 14a with boundary lines 15a and 15b parallel to the shaft contour can be provided. For the electrically inductive heating, the punch knife 1 has a connection element 14o for connection to the Positive pole of a current source and a connecting element 141 for connection to the negative pole of the current source. Furthermore, the punching knife 1 is provided with incisions or recesses 142 which start from its back 16 and each end at the same distance a from the teeth 3 or from the cutting contour 4. The recesses 142 preferably each have the same width and the same expediently also applies to the tab-like projections 143 located between the recesses 142 and extending from the chamfers 14, 14a to the back 16. Both the recesses 142 and the projections 143 are dependent on the cutting contour 4 and the shape and height of the wave crests 5 and the troughs 6 of different lengths. Irrespective of this, recesses 142 and projections 143 of the same length can optionally be repeated periodically over the length of the punching knife 1.

Between the inner ends 144 of the recesses 142 and the teeth 3 there is a web-shaped area 145, which serves as an uninterrupted current path for the electrical current flow over the length of the knife.

The wave crests 5 and the wave troughs 6 can each be the same height or the same depth or different height and different depth in the same punching knife 1. The recesses 142 and the tab-like projections 143 are then to be adapted accordingly, so that web-shaped regions 145 with a constant cross section corresponding to the distance a remain.

The invention is not restricted to the exemplary embodiments shown in the figures. Rather, further modifications and refinements are also possible within the scope of the inventive concept. This includes, in particular, that features of different exemplary embodiments are interchangeable with one another, insofar as this is useful and expedient.

Claims (29)

1. A stamping blade for severing non-metallic parts, in particular single-layer and multi-layer parts containing plastics material, comprising a flat blade body (2) and teeth (3) which are connected along a base line to the blade body (2) and whose tips (7) project to different distances in the direction of the stroke movement of the blade, characterised in that the base line extends in a wavy configuration and that there is a cutting contour (4) with wave crests (5) and wave troughs (6), which contour extends in the plane of the blade and includes the tooth tips (7), adjacent wave crests (5) and wave troughs (6) having at least three teeth (3).
2. A stamping blade according to claim 1 characterised in that the wave crests (5) and the wave troughs (6) respectively are of equal height with respect to a respective common level line (18 and 19 respectively).
3. A stamping blade according to claim 1 characterised in that the wave crests (5a) are each of the same height and the wave troughs (6a) are of different heights (Figure 2).
4. A stamping blade according to claim 1 characterised in that the wave crests (5b) are of different heights and the wave troughs (6b) are each of the same height (Figure 3).
5. A stamping blade according to claim 1 characterised in that the wave crests (5c) are of different heights and the wave troughs (6c) are of different heights respectively (Figure 4).
6. A stamping blade according to one of the preceding claims characterised in that the teeth (3) are directed in the direction of the stroke movement of the stamping blade (1, 1a, 1b, 1c).
7. A stamping blade according to one of the preceding claims characterised in that the cutting contour (4a, 4b, 4c) comprises similar groups of wave crests (5a, 5b, 5c) and wave troughs (6a, 6b, 6c).
8. A stamping blade according to one or more of the preceding claims characterised in that level lines (18-22b) extend parallel to the back (16) of the stamping blade (1) and that the teeth (3) are normal to the back (16).
9. A stamping blade according to one or more of the preceding claims characterised in that at least one side (24, 25) of the stamping blade (1) has a chamfer (14, 23) in addition to the teeth (3) along the cutting contour (4).
10. A stamping blade according to claim 9 characterised in that the chamfer (23) extends parallel to the cutting contour (4).
11. A stamping blade according to one or more of claims 9 and 10 characterised in that the chamfer (14) extends parallel to the back (16) or to a level line (19).
12. A stamping blade according to one or more of claims 9 to 11 characterised in that the chamfer (14) is concave in cross-section in the manner of a flute.
13. A stamping blade according to one or more of the preceding claims characterised by a blade height (H) such that the stamping blade can be used in severing a three-dimensional part in silhouette.
14. A stamping blade according to one or more of the preceding claims characterised in that the wave crests (5) and the wave troughs (6) merge continuously one into the other.
15. A stamping blade according to one or more of the preceding claims characterised in that a heating device (28) is associated with the stamping blade (1, 1a, 1b, 1c).
16. A stamping blade according to one or more of the preceding claims characterised in that there are provided openings (142) which start from its back (16) and which each terminate at a respectively identical distance (a) from the teeth (3) or the cutting contour (4) respectively.
17. A stamping apparatus having at least one stamping blade (1, 1c or 103) according to one or more of the preceding claims and a machine frame structure and at least one drive (32) for at least one stamping blade (1), with at least one hold-down means (51) for the workpiece and at least one co-operating tool (61) for the stamping blade or blades (1), characterised in that the hold-down means (51) is movable by the drive (32) of the stamping blade (1) and together with the stamping blade (1) towards and away from the workpiece and is movable relative to the stamping blade (1), wherein the hold-down means (51) is mounted on a movable part (38) of the drive (32) of the stamping blade (1) and is movable relative to same.
18. Apparatus according to claim 17 characterised in that the hold-down means (51) guides the stamping blade (1).
19. Apparatus according to one or more of the preceding apparatus claims characterised in that the hold-down means (51) has at the workpiece side at least one adhesion portion (60) for fixing a workpiece.
20. Apparatus according to one or more of the preceding apparatus claims characterised in that the co-operating tool (61) for the stamping blade (1) has a cutting gap (64), a groove, a cutting passage or the like.
21. Apparatus according to one or more of the preceding apparatus claims characterised in that adhesion portions (70) define the cutting gap (64) of the co-operating tool (61).
22. Apparatus according to one or more of the preceding apparatus claims characterised in that abrasive cloth and/or hook-and-loop strip and/or other projections and recesses are provided as the adhesion portion (60, 70).
23. Apparatus according to one or more of the preceding apparatus claims characterised in that the adhesion portion (60, 70) is arranged on a supporting metal portion/metal plate.
24. Apparatus according to one or more of the preceding apparatus claims characterised in that the adhesion portion (70) has an edge strip (71) projecting into the cutting gap (64) perpendicularly to the direction of stroke movement of the stamping blade.
25. Apparatus according to one or more of the preceding apparatus claims characterised in that the stroke movement for the stamping blade is so selected and the height (H) of the stamping blade (1) is such that a three-dimensionally shaped thin-walled workpiece (82) can be severed in silhouette.
26. Apparatus according to one or more of the preceding apparatus claims characterised in that the bottom former of the bottom tool into which the co-operating tool (61) is integrated at least partially comprises plastics material.
27. Apparatus according to one or more of the preceding apparatus claims characterised in that the bottom former is a deep-drawn plastics shell.
28. Apparatus according to one or more of the preceding apparatus claims characterised in that the hold-down means (51) is acted upon by a spring (62) whose spring force is adjustable.
29. Apparatus according to one or more of the preceding apparatus claims characterised in that at least one inflatable hose (43) is provided as the drive element.

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