EP0528147A1 - Punch for producing grater elements - Google Patents

Abstract

A punch (1) is proposed for producing grating elements (20) according to the invention, the grating elements (20) being formed from a metal sheet as the punch (1) penetrates the latter. In its end region (6, 7, 8), with which it interacts with the sheet during the forming operation, the punch (1) comprises a stub (6) of essentially square cross-section, adjoining which is a pyramid-shaped end piece (8). Two opposite side faces (18) and (19) of the pyramid-shaped end piece (8) have essentially the same angle of inclination (b and a respectively) in relation to their centre line (10 and 9 respectively) whereas the common angle of inclination (b) of one pair (18) of side faces differs from the angle of inclination (a) of the other pair (19) of side faces. As a result, the two opposite sheet-metal tabs (25) are curved in such a way that their sharp-edged rim (28) points in the circumferential direction (U), giving a sharper grating disc (21). <IMAGE>

Description

The invention relates to a tool stamp for producing friction elements which are formed when the latter penetrates a sheet, the tool stamp, in its area interacting with the sheet during the molding process, consisting of a stump which is essentially square in cross section and on which there is a pyramid-like end piece connects.

Such a tool stamp has long been used in the manufacture of friction elements in industry. With this tool stamp, the end piece is formed by an even pyramid, in which the four side surfaces converge to a point. The tip is flattened and forms a square cross-section to the base. A square is connected to the base of the pyramid as a stocking, the square cross section of which corresponds to the base of the pyramid.

If one produces friction elements with this tool stamp, then when the tool stamp is pierced through the metal sheet, four sheet metal tabs are formed which extend essentially in the direction of the longitudinal axis of the tool stamp. Although the friction results achieved with these friction elements are satisfactory, the contact pressure of the foodstuffs, for example raw potatoes, against the surface of the friction disc must be relatively high, although the edges of the sheet flaps which are directed upward from the disc and which arise when the plate is torn open, are sharp and are fine-toothed.

In order to reduce the friction time while keeping the contact pressure within acceptable limits, a friction disc was created in which two of the four protrude from the surface of the friction disc Sheet metal tabs are directed away from the punch axis, which extends perpendicular to the surface of the friction disk and which have a curvature, so that the sharp edges are directed in the circumferential direction towards the friction disk. Such friction disks have been commercially available for a long time in connection with the "Braun Multipraktik Plus Electronic De Luxe, Type UK 400". Such a kitchen machine with the friction disc offered can also be found on pages 32, 33 (third disc from the left), 35 (image 5, second disc from the left) and 36 (third disc from the left, top image) from the "Braun product range 1990" ), can be seen. Although only 19 friction elements are arranged on the crescent-shaped friction disc, better friction results compared to the conventional friction discs are nevertheless achieved by means of the two sheet metal tabs curved in the circumferential direction of the friction disc, that is to say in the direction of rotation.

The object of the invention is now to provide a tool stamp and a method which can be carried out with this tool, by means of which the friction elements known from the "Braun friction disc" can be produced in only one deformation method.

This object is achieved with a tool stamp according to the invention in that two opposite side surfaces of the pyramid-like end piece have essentially the same angle of inclination with respect to their central axis, but that the common angle of inclination of one side surface pair differs from the angle of inclination of the other side surface pair. Due to the different angles of inclination of the two pairs of side surfaces relative to each other, when the tool stamp is inserted into the sheet metal, those two opposite sheet flaps are rolled up more - and thus have a greater curvature - which are acted upon by the side surfaces provided with the larger angles of inclination, while the other two opposite sheet metal tabs just shaped out of the sheet that they are directed vertically upwards from the surface of the friction disc. And this is only achieved by the different angles of inclination of the two side surface pairs, while when using a uniform truncated pyramid - even if larger angles of inclination are used on all side surfaces - this effect does not occur. Due to the two more curved or more rolled sheet metal tabs towards the circumferential direction of the friction disc, these act like knife edges on their edge, since they penetrate vertically into the surface of the food during the rubbing process. Due to the cutting action of the two more curved sheet metal tabs, a better rubbing result is achieved during the rubbing process. On the other hand, the other two sheet metal tabs, which run essentially in the longitudinal direction of the stamp axis, continue to act on the foodstuffs to be grated like a scraping tool, since the sharp-edged edge runs in the longitudinal direction of the foodstuffs to be grated and not perpendicularly or transversely to them.

The stronger rolling up of two sheet metal flaps lying opposite one another is particularly amplified by the fact that the tip resulting from the different angles of inclination of the two side surface pairs on the pyramid-shaped end piece is formed by an edge which runs essentially parallel to those outer surfaces of the stump which is square in cross section, which are provided with the larger angle of inclination. This then results, according to the invention, in differently sized pairs of trapezoidal sheet metal tabs, of which the two more curved sheet metal tabs have the larger surface and a flattened cutting edge and are therefore also rolled or curved more sharply, while the other two sheet metal tabs each taper to a point.

It is particularly advantageous that the tip of the pyramid-shaped end piece of the tool stamp is flattened in such a way that there is a square face with two sides of equal length. As a result, the two pairs of trapezoidal metal tabs differ in terms of their surface area, which favors the rolling effect of the sheet metal tabs provided with a larger surface, while the other two sheet metal tabs rolled only very little and therefore essentially in the longitudinal direction of the tool stamp, i.e. perpendicular to the surface of the Friction disc, run upwards. The flattening of the tip of the tool stamp according to the invention also prevents a splintering of a sheet metal splinter from the friction disk during the piercing process, which can occur more frequently in the case of a tool stamp with an evenly formed pyramid as the end piece. Accordingly, no more sheet splinters get between the punch press tool and the friction disk, so that damage to these parts is avoided.

Particularly sharp friction elements can be produced without a sheet splinter breaking off if the end face of the tool stamp runs perpendicular to its central axis and consequently forms a rectangular surface. This arrangement results in a particularly abrupt tearing of the opening formed during the shaping process of the sheet metal tabs, which leads to sharp edges on the sheet tabs that arise from the sheet metal tabs due to the flowing material during the separating process. In addition, different cutting edges are achieved, of which one pair of sheet flaps has a tip and the other pair of sheet flaps has a sharp edge but is flattened at the tip.

Particularly pronounced sheet metal tabs with sharp edges and strongly curved sheet metal tabs with a relatively small opening with a square cross section is achieved in that for the formation of friction elements on up to approximately 2 mm thick steel sheets, the angle of inclination of one pair of side surfaces is approximately 11 ° and the angle of inclination of the other Side surface pair is about 15 °, that the side length of the square stump is about 24 mm and that the two side lengths of the end face are about 0.7 mm and 0.1 mm.

If a friction disc is produced according to the method according to the features of claim 5, particularly sharp friction elements are created in a single operation, which enable vegetables to be grated particularly quickly. To produce a friction element, the sheet is fixed in position in a holding tool and is supported on the top in the area around a friction element by an annular support, the tool stamp being pushed through the sheet by means of a tool press from the underside of the sheet until the the square die partially penetrates into the sheet, the tool stamp being pulled out of the sheet completely after this molding process. The ring-shaped support, which surrounds the bent sheet metal tabs in the manufacture of one friction element and rests against the surface of the friction disc so that the sheet is not bent too much in the area of the friction elements, but is suddenly torn open by the tool stamp in four sheet tabs, which then be molded out of the plane of the friction disc due to material displacement.

Figur 1

Ansicht auf den Werkzeugstempel nach der Erfindung,

Figur 2

Seitenansicht von vorne, wie in Fig. 1 dargestellt, auf den Stumpf mit anschließendem Endstück, jedoch in vergrößertem Maßstab dargestellt,

Figur 3

Seitenansicht in Richtung X gemäß Fig. 2, ebenfalls in vergrößertem Maßstab dargestellt,

Figur 4

Draufsicht auf den Werkzeugstempel in Richtung Y nach Fig. 2,

Figur 5

Draufsicht auf ein Reibelement, das im vergrößerten Maßstab dargestellt ist und das mit dem nach den Fign. 1 bis 4 dargestellten Werkzeugstempel hergestellt ist,

Figur 6

Längsschnitt durch das Reibelement gemäß der Schnittführung VI-VI nach Fig. 5,

Figur 7

Längsschnitt durch das Reibelement gemäß der Schnittführung VII-VII nach Fig. 5, jedoch um 90° in der Zeichenebene gedreht,

Figur 8

Draufsicht auf eine Reibscheibe, deren Reibelemente mit dem in den Fign. 1 bis 4 dargestellten Werkzeugstempel herausgeformt wurden und

Figur 9

Teilschnitt durch eine Werkzeugpresse mit Spannvorrichtung für die Reibscheiben und mit einem in der Werkzeugpresse angeordneten Werkzeugstempel nach der Erfindung.

The invention is explained in more detail with reference to the accompanying drawings. Show it:

Figure 1

View of the tool stamp according to the invention,

Figure 2

Side view from the front, as shown in Fig. 1, on the stump with subsequent end piece, but shown on an enlarged scale,

Figure 3

Side view in the direction X according to FIG. 2, also shown on an enlarged scale,

Figure 4

Top view of the tool stamp in the direction Y according to FIG. 2,

Figure 5

Top view of a friction element, which is shown on an enlarged scale and with the according to FIGS. 1 to 4 shown tool stamp is made,

Figure 6

Longitudinal section through the friction element according to the cut VI-VI of FIG. 5,

Figure 7

Longitudinal section through the friction element according to the cut VII-VII of FIG. 5, but rotated by 90 ° in the plane of the drawing,

Figure 8

Top view of a friction disc, the friction elements with the in the Figs. 1 to 4 tool stamp shown were formed and

Figure 9

Partial section through a tool press with a clamping device for the friction disks and with a tool stamp arranged in the tool press according to the invention.

In Figs. 1 and 4, the tool stamp 1 consists of a cylindrical shaft 2 which is circular in cross section and which is adjoined at the lower end by a truncated cone 3 which widens downward and which then ends in a cylindrical section 4. At the upper end in FIG. 1, the shaft 2 tapers over step 5, from where, according to FIGS. 1 to 4, a stump 6 with a square cross section connects, which tapers towards the tip 7 via a pyramid-like end piece 8. The shaft 2, the truncated cone 3, the cylindrical section 4, the step 5, the stump 6, the end piece 8 and the tip 7 run symmetrically to the central axes 9, 10 (FIGS. 1 to 4). The one in Cross-sectionally square stump 6 begins at line 11 and ends with its two side surfaces 13 at the edges 12 running perpendicular to the center line 9 and with its two other side surfaces 14 at the edges 15 also running perpendicular to the center line 10.

As shown in Figs. 2 and 3 can be seen, the two edges 12 run at a small distance c above the edges 15. This results, on the one hand, from the fact that the tip 7 is formed by a surface which is rectangular in cross section and extends perpendicular to the central axes 9, 10 and the like Sides 16 with the length d of 0.1 mm and their sides 17 with the length e of 0.7 mm are fixed and, on the other hand, from the fact that trapezoidal surfaces 18 adjoin the sides 16 and trapezoidal surfaces 19 adjoin the sides 17, 2, the surfaces 19 at an angle a of approximately 15 ° to the center line 9 and, according to FIG. 3, the surfaces 18 at an angle b of approximately 11 ° to the center line 10 downwards. It follows from this that there is a distance c between the edges 12 and 15, which is approximately 0.08 mm for the given dimensions. The side surfaces 13 and 14 of the stump 6 are approximately 2.4 mm, while the diameter of the shaft 2 is four mm. As the fig. 1 to 4 show, the pyramid-shaped end piece 8 takes the form of a hipped roof known from roofs of houses.

In Figs. 5 to 7, a friction element 20 is shown, which with the on the basis of FIGS. 1 to 4 described tool stamp 1 was produced. 8 shows a crescent-shaped friction disk 21 in plan view, which is provided with a plurality of friction elements 20. Holes 23 are punched out on the friction disk 21 for the purpose of saving material and for passing friction material. As shown in Figs. 5 and 8 clearly shows, each friction element 20 consists of an opening which is essentially square in cross section 24, which during the punching and pulling process of the in FIGS. 1 to 4 shown end piece 8 and the subsequent stump 6 of the tool stamp 1 is formed by the sheet.

In each case on the four sides of the opening 24, according to FIGS. 6 and 7 in the punch direction Z directed sheet metal tabs 25, 26, of which the sheet tabs 25 according to FIG. 6 are curved in the circumferential direction U or, depending on the arrangement, also in the radial direction of the friction disk 21. The sheet flaps 26, on the other hand, extend upward in the stamp direction Z according to FIG. 7 and accordingly do not have the curvature 27 which the sheet tabs 25 according to FIG. 6 have. The strongly curved sheet metal tabs have the effect that their sharp-edged edge 28 acts like a knife edge, which cuts substantially vertically into the surface of the food item when food is guided in the circumferential direction U against the sheet metal tab 25 on the right in FIG. 6. In FIG. 7, however, the sharp-edged edge 29 is directed upward in the stamping direction Z, so that when foodstuffs are guided in the circumferential direction U against the sheet metal tabs 26, these only scrape off foodstuffs from their surface. As shown in Figs. 5 and 6, the more curved sheet-metal tabs 25 lie opposite one another, their sharp-edged edges 28 facing away from one another. The sheet metal tabs 26 run according to FIGS. 5 and 7 perpendicular to the metal tabs 25 and are also diametrically opposite.

In order to obtain sheet metal tabs 26, 27 of different shapes in a single operation, the invention differs according to FIGS. 2 to 4 of the angle of inclination a of one side surface pair 19 from the angle of inclination b of the other side surface pair 18, that is to say that the side surface pairs 19 ensure, owing to the larger angle of inclination a, that the metal tabs 25 (FIG. 6) are curved more than the side surface pairs 18 due to the smaller angle b to the through it shaped sheet metal tabs 26 (Fig. 7) cause. Because of the larger angle of inclination a on the side surfaces 19 (FIGS. 2 and 4), the sheet metal flaps 25 deformed by these side surfaces 19 (FIGS. 5 and 6) are rolled more so that the sharp-edged edge 25 is directed more in the circumferential direction U.

The rolling effect on the two metal tabs 25 is further supported by the fact that the surface of the tip 7 is formed by a rectangle, the shorter sides 16 (length d) parallel to the side surfaces 13 and the longer sides 17 (length e) parallel to the side surfaces 14 run (Fig. 4). This is because, as a result, the distance f from the side 16 to the side surface 17 is smaller than the distance g from the side 17 to the side surface 14, the surfaces 18 are therefore smaller than the surfaces 19, so that the surfaces 19, 18 from the surface Surface 22 of the friction disks 21 upwardly shaped sheet metal tabs 25, 26 have surfaces of different sizes, i.e. the two sheet metal tabs 25 have to be displaced perpendicularly to the punch direction due to their larger surface area and due to the larger inclination angle a on the tool punch 1 during the punching and piercing process Z take up as the sheet metal tabs 26. Because of the greater lateral displacement, the sheet metal tabs 25 are rolled more and are flattened at the tip 41, while the sheet tabs 26 have a tip 42.

In Fig. 9 the punching and drawing tool 29 is shown, which consists of an upper and lower part 30, 31, between which the friction disc 21 is clamped for its attachment. A tool press 32 is formed above the friction disk 21, in which the tool stamps correspond to the number of friction elements 20 (FIG. 3) 1 are fixed in holes 33. The truncated cone 3 and the cylindrical section 4 with its support surface 34 (FIG. 1), which are inserted into a cavity (not shown in FIG. 9) at the upper end of the bore 33 of the tool press 32, serve as the securing means for the tool stamp 1. On the upper side 22 of the friction disk 21 there is an annular support 36, which runs concentrically to the central axis 9 of the tool stamp 1 and whose cavity 37 serves as a receptacle for the sheet metal tabs 25, 26 (FIGS. 5 to 7) during the molding process of the friction elements by the tool stamp 1.

The operation of the punching and drawing tool 29 according to FIG. 9 is as follows:
In order to be able to insert a friction disk 21 between the upper and lower part 30, 31, the lower part 31 according to FIG. 9, for example, has to be moved downward, so that the clamping point 38 is exposed to the extent that a friction disk 21 can be used. 9 is then raised until the edge 39 of the friction disk 21 is firmly clamped in the clamping point 38. In this position, the friction disc 21 rests with its upper side 22 against the annular supports 36, which are part of the lower part 31, as shown in FIG. 9.

Now the tool press 32 moves towards the underside 40 of the friction disk 21 until the tip 7 pierces the friction disk 21 and thereby tears open the plate of the friction disk 21 in the manner shown in FIGS. 5 to 7 show that thin-walled sharp edges 28 arise. Due to the different angles of inclination a, b the metal tabs 25 rolled more like the sheet tabs 26, which then protrude into the cavity 37 of the support 36. The tool stamp 1 travels so far into the sheet metal of the friction disk 21 that the stump 6 with a square cross section penetrates only slightly into the underside 40 of the friction disk 21. After this punching and drawing process, the tool press 32 with the tool stamp 1 according to FIG. 9 moves up again. The lower part 31 then moves downward, so that the friction disk 21, which is now provided with friction elements 20 according to FIGS. 5 to 8, can be removed from the drawing tool 29.

In order to avoid repetitions, the same item numbers were chosen for correspondingly identical elements in the figures.

Claims (6)

Tool stamp (1) for producing friction elements (20) which, when penetrating a sheet, are formed from the latter, the tool stamp (1) in its area interacting with the sheet during the molding process from a stump (6) of essentially square cross section. there is a pyramid-like end piece (8),
characterized,
that two opposite side surfaces (18 and 19) of the pyramid-like end piece (8) with respect to their central axis (10 or 9) have essentially the same angle of inclination (b or a), but that the common angle of inclination (b) one side surface pair (18) differs from the inclination angle (a) of the other side surface pair (19). Tool stamp according to claim 1,
characterized,
that the end (7) of the pyramid-like end piece (8) is flattened in such a way that a square end face (7) with two equally long sides (16, 17) is formed there. Tool stamp according to claim 2,
characterized,
that the end face (7) extends perpendicular to the central axis (9 or 10) of the tool stamp (1) and consequently assumes a rectangular shape. Tool stamp according to claim 3,
characterized,
that for the formation of friction elements in steel sheets up to about 2 mm thick, the angle of inclination (b) of the one side surface pair (18) about 11 ° and the angle of inclination (a) of the other side surface pair (19) is about 15 °, that the side length of the cross-sectional area of the square stump (6) is about 24 mm and that the two side lengths (e, d) of Front surface of the tip (7) be about 0.7 mm and 0.1 mm. Method for producing friction elements (20), which are formed on a sheet by means of a tool stamp (1), the individual friction element (20) having an opening (24) that arises only during the molding process, around which a plurality of sheet metal tabs deformed in the punch direction (Z) (25, 26) are arranged, which are torn and deformed from the sheet during the molding process, and which have sharp edges at their edge (28), two sheet metal tabs (25) lying opposite one another and a curvature directed away from the punch axis (9) ( 27) have
characterized,
that a tool stamp (1) according to one of the claims 1 to 4 is used to produce each friction element (20). Method according to claim 5,
characterized,
that to produce a friction element (20), the sheet is fixed in position and is supported on the top (22) in the area around a friction element (20) by an annular support (36), that the tool stamp (1) by means of a tool press (32) from the underside (40) of the sheet metal is pressed through the sheet metal until the cuboid stump (6) penetrates into the sheet metal and that after this molding process the tool stamp (1) is pulled out of the sheet metal again.

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