EP0173042B1 - Punching device, especially for abrasive paper or abrasive cloth - Google Patents

Abstract

1. Punching device, particularly for stip or foil-type material, preferably for abrasive paper or grinding cloth, with a punch part (1) carrying at least two punches (2 to 8) and a foldable die part (9) connected to it and provided with a number of dies (10 à 16) corresponding to the number of punches, characterised in that when the device is folded together a punch (2 to 8) engages in each case with each die (10 to 16), whereby in the case of several punches at different distances from the folding axis at least the cutters (36) of the punches (3 to 8) which are located at a greater distance from the folding axis are inclined in such a way to the plane of a punch holding plate (30), that their cutter area (37) associated with the folding axis (17) is at a greater distance from the plane of the punch holding plate (30) than the cutter area (38) which is at a distance from the folding axis and in that the punches (2 to 8) outside of the cutter (36) are tapered towards the attachment end on the punch part (1).

Description

The invention relates to a punching device, in particular for tape-like or foil-like material, preferably for sandpaper or sanding canvas, with an at least two punch stamps or the like Number of die parts provided with dies. Such a punching device has become known from DE-A-2 306 221. It is equipped with a fixed number of dies that can be used as holes and can be equipped with a maximum number of punches corresponding to this number of dies. The punches are detachable and can be attached to a tubular guide up to the maximum number. It is also possible to use only one punch, remove it after punching a hole, and then attach it to the next guide.

Regardless of whether you assign a punch to this die or implement a single one after each punching process, a material, for example a sheet of paper, can basically only be provided with several holes one after the other, because the punches cannot be actuated together, but only individually.

There are now applications for such a punching device, in which the film-like material must in principle be provided with several punching holes. Although this is possible with the previously known punching device, the time required is comparatively large and the punching is therefore expensive. In addition, the punching is not carried out with the closing of this punching device, but after the closing by pressing each punch separately. There is then the risk that the material to be punched will shift after one or the other punching process relative to the device, so that the intended hole spacing is no longer correct.

The object of the invention is to develop a punching device according to the preamble of claim 1 so that with it a planned number of holes quickly, accurately and preferably also with as much as possible

can be punched with little effort. To achieve this object, it is proposed according to the invention that in a punching device, in particular for tape and film-like material, preferably for sandpaper or sanding canvas with an at least two punch stamps or the like The like. Corresponding number of dies provided with a die part engages in each die with a collapsed device, whereby in the case of a plurality of punches or the like which are at different distances from the folding axis, at least the cutting edges of the punches or the like which are further away from the folding axis. run inclined to the level of a punch holding plate in such a way that its cutting area assigned to the folding axis is further away from the level of the punch holding plate than the cutting area remote from the folding axis, and that the punching dies are located on the outside from the cutting edge to the fastening end on the punching stem rejuvenate fur.

With this punching device, at least two holes can now be punched simultaneously, but in a preferred manner, in particular when punching sandpaper or sanding canvas, normally more than two holes are made per punching process. The punching takes place when the device is closed. Twisting or moving the material relative to the punching device is then no longer possible if the punching process is initiated at the second hole. Thus, the material can be punched quickly with the exact spacing of the various holes. This is particularly important when it comes to punching sandpaper or a sanding screen which, after punching, is attached to a device with dust extraction, in particular a so-called orbital sander, which is equipped with suction channels, the punched holes exactly matching the hole pattern Suction channels must correspond. Through the punched holes and the suction channels of the grinder, the grinding dust is constantly extracted during grinding. This punching device enables, for example, the user of a grinding device with a suction device to cut off the grinding canvas or sandpaper required for this purpose from a roll and then to punch them himself.

This is much cheaper than sandpaper bought sheet by sheet, which is punched in the factory with a punch press. In addition, the user of such a device can quickly help himself in an emergency if he has too large sandpaper that he can easily cut to the required size, but which is initially unpunched.

If, for the sake of simplicity, only "sandpaper" or "orbital sander" is referred to below, this should not be understood as restrictive.

. Of course, the arrangement of the punch and dies of the device must correspond as closely as possible to the arrangement of the suction channel mouths on the grinding plate of the orbital sander. In addition, the punch cross section must be at least substantially the same as the cross section of the suction channel mouth.

As I said, the punching takes place after the Insert the material by closing it. After opening, the punched sandpaper can be removed. Basically, it doesn't matter whether you move the dies against the punch or vice versa or swivel both parts. Expediently, however, the punched material or sanding paper is placed on the die part or the die ends on the die side, the die part resting on a solid base and the die part preferably being folded 180 ° against the die part. The latter can be formed relatively easily as a flat surface, so that a good support of the sanding paper is guaranteed.

Due to the inclined course of the cutting edges of at least the punch or the like located further away from the folding axis relative to the plane of the punch holding plate, a pulling cut is advantageously achieved in each case. As a result, the effort required for the individual punching process is reduced and, moreover, this is also advantageous for the punching process as such and also for the punching quality. The low expenditure of force is particularly advantageous if a plurality of punching tools are arranged parallel to the folding axis and then work simultaneously when folded. When closed, i.e. H. collapsed punching device, i.e. after all punching operations, the punch holding plate runs parallel to the plane of the material to be punched or the sanding paper.

By tapering the punch from the cutting edge to its fastening end, which is comparable to a so-called undercut, you create the necessary space for the dies or with respect to the dies. So that a cutting edge is created, a conical contour is of course also provided on the inside, at least at the free punch end.

A further development of the invention consists in that, in a punching device with circular punch cutting edges, the fold line on the fold axis side of each punch stamp tapering in the shape of a truncated cone forms at least a greater angle with the plane of the punch stamp holding plate than the fold axis distant coat line with this plane, whereby the angle of the surface line close to the folding axis with said plane is approximately 90 °. In the case of a circular die bore and punch cutting edge, the latter is moved on a circular arc due to the folding axis connection of the two device parts, so that when the cutting part near the folding axis is immersed in the die, the plane of the cutting edge forms an acute angle with the plane of the die. When folding further, the punch therefore needs the undercut mentioned on its region near the folding axis, which enables the further folding movement. In other words, due to this design, circular dies and stamps with a circular cutting edge can be used, so that the stamps can be manufactured, for example, as turned parts. This contributes significantly to the cheaper manufacture of this punching device. If you were to choose a circular cylindrical outer contour of the punch in the case of a circular punch die, the bore of the die would have to be oval or elliptical in order to enable mutual penetration during the folding movement.

Another embodiment of the invention provides that the punches have the shape of a truncated cone with parallel, perpendicular to the central axis base surfaces and the contact surface on the punch holding plate runs inclined at least for the punch axis distant punch. The desired oblique position for the drawing cut and the "undercut" required for the circular die holes are thereby achieved on the one hand. In addition, the punches can now be designed as simple turned parts, in particular produced on an automatic machine, which are separated from the bar material by simple parting off. Of course, you could also achieve the inclined position of the cutting edge of the punch by letting the two end faces of the punch run at an angle to one another, but this would entail an expensive manufacture of the punch.

The inclined support surfaces for at least a part of the punch are formed in a particularly advantageous manner by oblique, bead-like features in the punch holding plate. These characteristics can be applied, for example, in one operation with holes to attach the punch.

A further embodiment of the invention is characterized in that the forms are deeper with increasing distance from the folding axis and at least the inclined punch is the same height or length. With increasing punching of the punching device, the matrices are moving closer and closer to a parallel position to the punch holding plate and thus also to the cutting edges of the punch. If the latter is of the same size for production-technical reasons, this could lead to the punch stamps remote from the folding axis already starting to work before the cutting axis closer to the folding axis have finished their cutting process. This would have the consequence that very many punchings are carried out at the same time, which requires a correspondingly high expenditure of force. To keep the latter as low as possible, you set the Punch stamps in different depths in the manner described. This ensures that the punching tools that are closer to the folding axis have at least largely ended their punching process before the punching tool or tools that are further away begin the punching process. This is particularly important if several punching tools are arranged in parallel to the folding axis.

At this point, it is expressly pointed out that a punch directly adjacent to the folding axis does not require an inclined punch cutting edge, because at the beginning of the cutting process, the die assumes a sufficient oblique position due to the relatively large angle between the two parts of the device, which makes a pulling cut, such as said, guaranteed even if the die edge runs parallel to the punch holding plate. However, in order that a simultaneous cutting of this inner or these inner punching tools with the next outer ones is avoided, it is advantageous if the inner punch is either made a little shorter or lower, or is set correspondingly deep in the punch holding plate.

The punches preferably have a sleeve-like shape, there being a fastening thread for a fastening screw in the inside of the sleeve which penetrates a corresponding hole in the punch holding plate.

A further variant of the invention is characterized by a stop for the material to be cut at the end of the stamping die part remote from the folding axis and a lateral guidance of the material to be cut, in particular on both parts of the device. The material to be cut or the sandpaper sheet or the sandpaper section is pushed along the guide of the die part and subsequently that of the punch part into a flat, opened device until the front end in the direction of insertion has reached the stop of the punch part. If necessary, the sandpaper runs under a folding axis. The lateral guidance of the stamping part can be somewhat narrower if the latter is folded in between the guide walls of the die part. In this context, it is particularly advantageous if a tear-off edge, in particular with teeth or the like, is provided on the end of the die part remote from the folding axis. This allows you to cut sections of roll goods to a precise size, which is defined by the distance of the stop from the tear-off edge. When punching, the part of the sanding belt resting on the die part is first punched. This is usually about half of the sandpaper. If the other half should also be punched, pull out the sandpaper and push it back in a position rotated by 180 °. The punching device is then closed again and this then leads to the holes on the other half of the sanding paper being punched out.

The matrices are formed directly on the die part, in particular formed by circular punch openings, and thus on the one hand of the simplest type and on the other hand extremely inexpensive to manufacture.

The invention is explained below with reference to the drawing. The drawing shows an embodiment of the invention.

• Fig. 1 eine Seitenansicht der aufgeklappten Vorrichtung, teilweise in vertikaler Richtung geschnitten,
• Fig. 2 eine Draufsicht auf Fig. 1

Here represent:

• 1 is a side view of the opened device, partially cut in the vertical direction,
• FIG. 2 is a top view of FIG. 1

The punching device consists essentially of the punch part 1 with the punch 2 to 8 and the die part 9 with the dies 10 to 16. The two parts of the device are connected to one another via a folding axis 17, which is preferably in two parts and can consist of two rivets 18 and 19 which connect corresponding tabs 20 and 21 of the two device parts to one another. Both the die part 9 and the stamping part 1 essentially consist of a flat plate with bent lateral edges. The two lateral edges 22 and 23 form a guide for the punched material to be inserted into the opened device in the direction of arrow 24, in particular sandpaper. When the device is folded, the lateral edges 25 and 26 of the punch part 1, which form a somewhat narrower second half of the guide, engage between these lateral edges 22 and 23. The sanding paper is optionally pushed under an imaginary folding axis 17, which is not provided in the exemplary embodiment. It lies on the upward-facing surface 27 of the die plates 28 before punching. The matrices consist of circular punchings, i.e. H. they are worked out directly from this die plate 28. Their arrangement is a mirror image of a plane passing through the folding axis 17 and extending perpendicular to the image plane in FIG. 2.

In contrast, the punches 2 to 8 are manufactured separately and are exchangeably fastened to the punch holding plate 20 with the aid of fastening screws 29. Each fastening screw penetrates a hole in the punch holding plate 30 and its thread engages in a nut thread 31 of the essentially sleeve-shaped punch. The width of the punched material or sanding paper corresponds to the inner distance between the two lateral edges 25 and 26 of the

Stamping part 1. It is pushed into the device until its front end in the insertion direction hits the stop 32, which is formed by an angling of the end of the stamping plate holding plate 30, which end is in particular divided into two parts. This end consisting of two lobes is again turned in the opposite direction and thereby forms support plates 33 and 34 for the opened device, which at the same time handle when closing the device, i. H. when punching. At the opposite end of the device, namely at the end of the die plate 28 remote from the folding axis, there is a tear-off edge 35 which is formed by a toothed or serrated transverse edge of this plate.

1 shows that the cutting edges 36 of the punch 3 to 8, that is to say the punch further away from the folding axis 17 in relation to the punch 2, are inclined to the level of the punch holding plate 39. In the case of the punch 2, such an inclined position would bring no advantage for the reasons mentioned above, which is why this punch is dispensed with. The inclined position is such that the cutting area 37 assigned to the folding axis 17 is at a greater distance from the plane of the punch holding plate than the cutting area 38 remote from the folding axis. This means that a pulling punch cut is achieved during cutting or punching. The latter is illustrated by the dash-dotted representation 39 of the folded-up die plate 28, although in normal use the punch part 1 is pivoted in the direction of arrow 40 by approximately 180 ° against the die part 9. In the relative position of the die 36 and die 11 there is an angle 41 between the two planes thereof, which means that first the area near the fold axis is cut and then the cut along the cutting edge slowly pulls towards the area 38 away from the fold axis.

The stamping dies have a substantially frustoconical shape, the truncated cones standing upside down to a certain extent, i. H. the punches taper from their cutting edge 36 towards the punch holding plate 30. With a rotationally symmetrical design and inclined central axis 43 of the assembled punch, in conjunction with the frustoconical shape, the jacket line 42 close to the folding axis encloses a greater angle with the plane of the punch holding plate 30 than the jacket line 44 remote from the folding axis. The former angle is somewhat less than 90 °. In this way, the die can be pivoted according to the dash-dotted lines 45 and 46 in spite of a circular cross-sectional shape relative to the punch against the arrow 40 without being obstructed by the cladding line 42 close to the folding axis.

The oblique position of the punch is achieved in a very advantageous manner by attaching oblique, bead-like features 47 to the attachment points of the punch holder plate 30 for the punches 2 to 8. The oblique position can be seen from FIG. 1 and corresponds to that of the cutting edges 36. The greatest depth 48 of these oblique features is the same for the punching dies 3 and 4 and 5 and 6 or 7 and 8, but the features for the punching dies 5 and 6 deeper than those for punches 3 and 4, while the features for punches 7 and 8 are deeper than those for punches 5 and 6. This is due to lines 49, 50 and 51 in FIG. 1 or their spacing symbolizes. It is achieved in this way that the punches 3 and 4 have finished their cutting process when the cutting process for the punches 5 and 6 begins. The same applies to the pairings of punches 5 and 6 with 7 and 8.

First, the punch 2 cuts, which cooperates with the die 10. It is shorter than the other stamps, which are the same height. Due to the lower height of the punch 2 compared to the punch 2 to 8 and due to the absence of an inclined position, a height distance 52 arises, which ensures that the cutting process only begins when a relatively small angle is enclosed by the two parts of the device. Nevertheless, the cutting process of the punch 2 is finished before working with the punch 3 and 4.

To form the die 36 is a conical extension 53 of

Stamping hole attached.

Claims (9)

1. Punching device, particularly for stip or foil- type mateial, preferably for abrasive paper or grinding cloth, with a punch part (1) carrying at least two punches (2 to 8) and a foldable die part (9) connected to it and provided with a number of dies (10 to 16) corresponding to the number of punches, characterised in that when the device is folded together a punch (2 to 8) engages in each case with each die (10 to 16), whereby in the case of several punches at different distances from the folding axis at least the cutters (36) of the punches (3 to 8) which are located at a greater distance from the folding axis are inclined in such a way to the plane of a punch holding plate (30), that their cutter area (37) associated with the folding axis (17) is at a greater distance from the plane of the punch holding plate (30) than the cutter area (38) which is at a distance from the folding axis and in that the punches (2 to 8) outside of the cutter (36) are tapered towards the attachment end on the punch part (1).

2. Device according to claim 1 with circular punch cutters, characterised in that the generatrix (42) on the folding axis side of each punch (2 to 8) which tapers into a truncated cone shape and at least of the punches (3 to 8) which are located at a greater distance from the folding axis forms a larger angle with the plane of the punch holding plate (30) than the generatrix (44) which is at a distance from the folding axis forms with this plane, whereby the angle of the generatrix (42) which is near to the folding axis with the above-mentioned plane (30) is approximately 90⁰.

3. Device according to claim 2, characterised in that the punches (2 to 8) have the shape of a truncated cone with parallel base areas running perpendicular to the centre line (43) and the contact surface at the punch holding plate (30) is always inclined at least for the punches (3 to 8) which are at a distance from the folding axis.

4. Device according to claim 3, characterised in that the inclined supporting surfaces for at least a portion (3 to 8) of the punches (2 to 8) are formed by oblique beaded-type shaped parts (47) of the punch holding plate (30).

5. Device according to claim 4, characterised in that the shaped parts (47) are deeper the further away they are from the folding axis (17) and at least the obliquely disposed punches (3 to 8) are of equal height or length.

6. Device according to at least one of the preceding claims, characterised in that the punches (2 to 8) have a sleeve-type shape, an attachment thread (31) being located inside the sleeve.

7. Device according to at least one of the preceding claims, characterised by at stop (32) for the material being cut at the end of the punch part (1), which is at a distance from the folding axis and a lateral cut material guide (22, 23; 25, 26), particularly on both device parts (1, 9).

8. Device according to claim 7, characterised by a sharp edge (35), particularly with toothing or the like at the end of the die part (9) which is further away from the folding axis.

9. Device according to at least one of the preceding claims, characterised in that the dies (10 to 16) formed on the die part (9) are formed particularly by circular punch holes.

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