EP2099586B1 - Flap wheel - Google Patents

Description

The present invention relates to a method of producing a flap wheel having a plurality of triangular shingled overlapping abrasive flaps adhered to a rotationally drivable plate-shaped carrier, the abrasive flaps having a first straight edge and a second straight edge adjacent thereto, a third straight Edge is present, which cuts at least in its extension both the first edge and the second edge.

Such flap grinding wheels are known in different embodiments. For example, that shows DE 295 10 727 U1 a sanding pad, on the support portion of an annular pad of individual abrasive slats is glued. In this embodiment, the grinding blades are trapezoidal and overlap shingles. There are also known lamellar grinding wheels, the shingled overlapping grinding blades are rectangular cut, which has the advantage in manufacturing that they can be cut without loss from a continuous band. Plate-shaped carriers can be equipped fully automatically with these rectangular slats, wherein the grinding slats are individually cut off from a band and arranged one behind the other on the grinding plate. As a disadvantage of this grinding blades is However, it is known that they lead to the hub portion of the sanding pad because of the overlap to a strong order. As a result, the number of grinding slats to be applied and thus the amount of abrasive belt located in the outer region of the grinding wheel is limited.

To solve the problem of heavy ordering is over DE 200 06 127 U1 a sanding disc with grinding blades known which have a sickle-like geometry. The inwardly decreasing width of these abrasive flaps reduces the material leading to the problematic application. Since this sickle-like geometry offers two parallel and above all equal edges, it is also possible to cut these special abrasive slats from a belt without loss. Because of the concave inner edge, however, it is problematic to automatically equip the plate-shaped carrier with these grinding lamellae.

The US 2 907 147 A shows a sanding pad whose support area is occupied with uniformly repeated overlapping sanding blades, which have the geometry of ring segments. The shape of the carrier area of the sanding pad can be followed so well, although the possibility of cutting the sanding blades without loss from a belt is abandoned. To counteract this disadvantage, reference is also made here to the possibility of trapezoidally cut grinding lamellae from a strip.

The object of the invention is now to propose an improved process for the production of the lamellar grinding wheels, with which lamellar grinding wheels can be produced with only a small amount of material.

This object is achieved by the method according to claim 1. Advantageous embodiments of the invention are mentioned in the subclaims.

A basic idea lies first in the geometry of the grinding blades, which essentially describes a triangle. Here, "essentially" means that one or even two of the vertices of the triangle may be cut off a small distance without detracting from the "triangularity" feature. According to the triangularity is sufficient, as long as by Cutting edges are shorter than the edges forming the triangle. If necessary, the edges of the triangles can also be slightly curved or wavy.

With these triangular grinding lamellae, there are many possibilities for influencing the properties of the lamellar grinding wheel by the occupation. In other words, it is essential to the invention that the course of the third edge intersects the other two edges, even if the corners are cut off if necessary, only in their imaginary extension. Although the edges may have a slightly curved or wavy shape, it is particularly advantageous for ease of handling if they are all rectilinear.

It may be advantageous to form the grinding lamellae as complete triangles, in particular as right-angled, isosceles or equilateral triangles. In a preferred embodiment because of the particularly simple manufacture, however, one of the corners, in particular the corner enclosed by the outer edge and the inner edge, that is to say the corner lying in the rear in relation to the direction of rotation, is cut off by one piece. This embodiment will be explained more specifically in the example description.

With respect to the grinding wheel, the first, in particular straight, edge forms a lower edge, which is placed on the carrier section in the later manufacturing process. The adjoining second edge forms an outer edge insofar as it comes to lie in the outer region of the grinding wheel and forms the outer contour of the lamellar grinding wheel with the other lamellae. The grinding blades have a third edge, which is aligned as an inner edge to the hub portion. According to the invention, the inner edge, at least in its extension, cuts both the lower edge and the outer edge.

In an embodiment which is advantageous with regard to uniform coverage, the lower edge and the outer edge of a grinding lamella enclose an angle of 90 °, the lower edge and outer edge forming an isosceles triangle can train. Due to this special shape, a laying angle is made possible, which leads to a favorable grinding behavior and good cutting. In addition, the straight side is particularly well suited for a guide when laying the Lammelenschleifscheibe. This triangular shape can be processed accordingly well.

In another particularly easy-to-process embodiment, the lamellae form isosceles and thereby given equilateral triangles whose lower edge rests on the plate-shaped support and whose bottom edge opposite corner is preferably cut parallel to the lower edge. This embodiment has the advantage that it can be fed as a pre-cut band of triangles hanging from each other to a feeder which occupies the plate-shaped carrier. The triangles hang together on a common base, which is formed by a side strip of the band. When covering the incoming, formed by the abrasive and precut tape is first placed with its in this case beveled end edge on the sloping outer support portion of the carrier and held by the existing adhesive there. After placing the still hanging by means of the side strip on the tape slat is cut off. The separation of the lamella succeeds advantageously parallel to the lower edge, so that the cut corner is formed.

The inventive triangular geometry of the grinding lamellae leads to a number of advantages: The first significant advantage is that the grinding lamellae can be cut without loss from a continuous band of sandpaper or abrasive cloth. In this case, an edge, advantageously the outer edge or the inner edge, formed by the band and therefore does not need to be cut. In addition, it is advantageous that, in principle, a small number of such inventive grinding lamellae is sufficient to cover the entire carrier section in a shingling manner. This can help to reduce costs. By a small number of grinding lamellae, a small angle of attack of the grinding lamellae results, which leads to a better grinding behavior and favors a flat design of the grinding plate. However, high-performance grinding wheels require a large number of fins, which bring a lot of material into the outdoor area.

Accordingly, it is advantageous to apply a large number of abrasive flaps on the carrier, which is also easily possible with the triangular shape, since triangular abrasive flaps lead in the interior only a relatively small order. Because of their inwardly directed tips, the triangular lamellar shape thus makes it possible to apply a large number of lamellae without the lamellae building up towards the bore. Since more abrasive material is present, a large number of fins leads to a longer service life of the tool. Here, "large number" means that the wearer carries more than 50, in particular more than 70, abrasive flaps or even more than 100 abrasive flaps. As is known, the inclination of the outer surface of the support provided for the application of the lamellae can be more or less inclined in accordance with the order due to the large number of abrasive lamellae.

Another advantage is that the overlap of a sanding pad covered with the triangular sanding blades is greatest in the edge region, where the highest speeds occur and where the preferred working zone lies. Thus, most of the material is available at the most stressed point of the grinding wheel, while on the inside, where only a small contribution to grinding is made, there is less abrasive material. This also increases the service life of the lamellar grinding wheel. With the occupancy according to the invention, a relatively large amount of abrasive material is thus concentrated in the outer region of the pane compared to a conventional lamellar grinding wheel equipped with rectangular lamellae. By concentrating the abrasive material where it is needed, the cutting performance can be increased.

A further advantage is that the occupation with the triangles results in uniform compaction of the material over the grinding surface. This is one Fitting the flap wheel with the entire grinding surface on the workpiece favors, which leads to a particularly comfortable and controlled handling and thus to a precise grinding.

It is also advantageous, above all, that a large number of properties can be set via the edge length of the abrasive lamellae, via the angle of application and via the coverage density. These factors can be used to generate different types of flap discs, from flat discs for grinding with large chipping to pot-shaped or funnel-shaped discs. By varying the dimensions, the number and the position angle of the triangular grinding lamellae, it is possible to produce a wide range from relatively flat to high cup-shaped lamellar grinding wheels with a large lamella projection.

In pot-like slices the abrasive slats are glued onto the carrier in such a way that the outer contour opens in a funnel shape towards the grinding surface and the outer edge of the grinding surface projects beyond the edge formed by the underside of the grinding slats and also the edge of the carrier. This creates an abrasive surface with a particularly thin rim and sufficient abrasive material. Such grinding wheels are particularly suitable for grinding in corners. Due to the protruding edge formed by the grinding lamellae, the workpiece to be ground is also protected from the edge of the plate-shaped carrier. In addition, with such pot-like slices, a particularly good surface grinding is possible because they ensure sufficient abrasive material with homogeneous density over the entire surface. Another advantage of the pot-type lamellar grinding wheel is that it has a recessed at the bottom of the funnel recording. In the cup-shaped flap grinding wheel, the position of the flange need not be lowered by the geometry of the carrier. Instead, the flange disappears due to the height of the applied lamellae. This fact also means that such a flap grinding wheel is well suited for surface grinding.

Figur 1:

einen Schleifteller mit einer dreieckigen Schleiflamelle,

Figur 2:

eine flache Lamellenschleifscheibe,

Figur 3:

eine topfförmige Lamellenschleifscheibe,

Figur 4:

ein geschnittenes Band,

Figur 5:

das Belegen eines Schleiftellers und

Figur 6:

eine Lamellenschleifscheibe

The invention will be described below with reference to FIG FIGS. 1 to 6 explained in more detail. Show

FIG. 1 :

a sanding pad with a triangular sanding blade,

FIG. 2 :

a flat flap wheel,

FIG. 3 :

a cup-shaped flap grinding wheel,

FIG. 4 :

a cut ribbon,

FIG. 5 :

the covering of a sanding plate and

FIG. 6 :

a lamellar grinding wheel

In FIG. 1 a carrier 1 is shown in the form of a round plate made of plastic, which has a standardized, the hub forming bore 2 in the middle. This standardized hole is suitable for the use of a fastening element for fastening the work spindle of a working machine. Although any plate shapes and sizes are conceivable, so in the present case is a carrier with a diameter of 115 mm. Instead of plastic, also carriers of fiber, wood or metal can be used. The carrier 1 has an annular, conically sloping outward support portion 3, which is centered on the axis. In the present example, the angle of the cone is about 12 °. Depending on this, angles between 10 ° and 30 ° can also be used. On the support section 3, two concentric sausages 4 are applied from adhesive during the manufacturing process, with which the individual grinding blades are glued. The automatic application of the sausages 4 is known per se and occurs, for example, in a first manufacturing step, after the raw plate has been gripped and placed on a holder.

After application of the adhesive, in a further production step, a grinding lamella 5, which according to the invention is triangular, is placed on the support section 3 with the lower edge 6 and glued by means of the sausages 4. The grinding blade 5 has an edge 6 adjacent to the lower edge 6. In this case Lower edge 6 and outer edge 7 each 30 mm long and arranged at right angles. The abrasive blade 5 is cut from an abrasive tape of 30 mm width. According to the invention, the grinding blade 5 is triangular, the inner edge 8 as a third edge, the lower edge 6 and the outer edge 7 intersects. The lower edge lies in the direction of rotation of the flap grinding wheel at the front. The grinding blade 5 thus has in the present case the geometry of a right-angled and isosceles triangle. This triangle is glued onto the carrier 1 in such a way that the perpendicular bisector 9 of the outer edge 7 is arranged radially. The radius 10 passing through the apex of the triangle is thus inclined by 23 ° with respect to the mid-perpendicular 10 (see angle α).

In FIG. 2 is a with 75 such triangular grinding blades 5 and thus fully occupied lamella grinding wheel 11 is shown, which is suitable for rotation in the arrow direction. The shingle-like overlapping of the sanding lamellae 5 can be seen automatically. The triangular sanding lamellae 5 were cut off from a sandpaper or abrasive fabric, ie an abrasive on a backing, by means of a cutting tool. Like the side view in FIG. 2b shows, the abrasive slats are glued to the support 1 so that the outer contour 12 has a waist, wherein the edge 13 of the grinding surface 14 has at least almost the same diameter as the edge 15 formed by the underside of the grinding lamellae. Clearly visible is also the flat grinding surface 14. Obviously, the triangular lamella shape makes it possible to apply a high number of lamellae without the lamellae building up to the bore 2.

In FIG. 3 a cup-shaped flap wheel 16 with 75 fins 17 is shown in perspective. The fins 17 have the shape of a right triangle with a bottom edge of 30 mm in length and an outer edge of 40 mm in length. It can be clearly seen that the edge 18 of the grinding surface protrudes beyond the edge 19 formed by the underside of the grinding lamellae and a high-building funnel or pot shape results. The intended direction of rotation is indicated by the arrow.

FIG. 4 shows a band 20 of known abrasive material, in which, for example, with a knife roller, not shown, a running line in a triangle 21 was cut. In addition to the central region slotted in this way, the band has left and right edge strips 22 of continuous material. It may be a quasi endless belt, which is pre-assembled wound on a roll and is moved in the direction of arrow A of the device for covering a sanding plate. The slotted area can also be introduced shortly before the receipt of a plate in a previously unslotted belt.

The strip 20 divided into two by the slit 21 is separated from its starting position into its two strips 20a and 20b, each of the strips 20a and 20b being subjected to separate further processing. Each of the strips 20a and 20b has, as a basis, the respective marginal tire with the triangles rising above it.

FIG. 5 shows the further processing of the part 20b, the initial triangle 24 is supplied to the plate to be occupied 23 by means of a not known per se known feed head. The upper grain of the band is indicated in the drawing. First, the band is wound so that the front edge 25 of the initial triangle 24 presses parallel to the surface of the support portion 3 in the adhesive sausages 4 and thus forms the lower edge. The process of loading is timed, with the plate 23 being rotated under the belt but resting when it is put on. After placement, the supply of the belt 20b stops and the attached starting blade 24 is separated from the belt 20b by a cut. This cut is performed by a knife provided on the feed head parallel to the lower edge 25. His direction is through the broken line 27 (see also FIG. 4 ) indicated. After the cut, the disc 23 placed on a corresponding holder continues to rotate one step in the direction of the arrow B before the band 20b rotates the next triangular lamella 26 on the plate 23 behind the latter previous seats. The drive of the band can be supported by a kind of gear whose teeth engage in the tooth gaps of the abrasive tape.

When all the lamellae are mounted, they are placed together in a further step by pressure from above to the plate before the fully occupied disc is removed and fed to a device which ensures the curing of the adhesive. In this way, the plate 23 is covered with lamellae whose three edges form an isosceles triangle whose corner forming the point is cut parallel to the opposite lower edge.

In this embodiment, the uncut edge 31 of the band 20b forms the inner edge of the triangular lamellae. It can be seen that the edge strip 22 is important for the cohesion of the triangular lamellae and for guiding the "serrated band" 20b. For this reason, it must also have a certain thickness, which is about 4 mm for the slats shown here a lower edge length of 40 mm. Because of the necessary severing of this edge strip 22, it also comes to the cut corner of the ansich triangular lamella.

In FIG. 6 Now a finished flap grinding wheel 28 is shown with the slats 29 cut in this way. It can be clearly seen that the upper edge 30 of the grinding surface no longer projects beyond the edge formed by the underside of the grinding lamellae.

Claims (6)

1. A method for manufacturing an abrasive flap disc with a plurality of triangular grinding flaps (5) that overlap each other like shingles and are adhesively bonded to a rotatingly drivable, plate-shaped carrier (1), wherein the grinding flaps (5) exhibit a first straight edge (6) adjoined by a second straight edge (7), wherein a third straight edge (8) is present that at least in its elongation intersects both the first edge (6) and second edge (7),
   characterized in that the grinding flaps (5) are cut as a plurality of grinding flaps without loss from a continuous tape (20) of an abrasive comprised of abrasive paper or abrasive cloth,
   that the tape (20) of abrasive is precut in such a way that the cut generates a slit (21) running along a triangular line, which separates the tape (20) into two strips (20a) and (20b), wherein one strip (20b) exhibits triangular flaps which are contiguous concerning their base and is fed to a device for fitting purposes,
   that the strip (20b) is wound in such a way that the front edge (25) of the first triangular flap (24) of the strip (20b) is placed on the carrier section (3) of the carrier (1, 23) and held by adhesive (4) applied there,
   that the placed first triangular flap (24) is separated by a cut (27) from the strip (20b), and
   that after separation, the carrier (23) is moved a step further into the position for placing the next flap (26).
2. The method according to claim 1,
   characterized in that
   the three edges (6, 7, 8) form an isosceles triangle, whose corner comprising the tip is cut parallel to the opposing lower edge.
3. The method according to claim 1 or 2,
   characterized in that
   the first edge forms a lower edge (6, 25), the adjoining second straight edge forms an outer edge (7), and the third edge forms an inner edge (8, 31), wherein the outer edges (7) of the grinding flaps (5) form the outer contour (12) of the abrasive flap disc (11).
4. The method according to one of the preceding claims,
   characterized in that
   the grinding flaps (24, 26) are adhesively bonded to the carrier (1, 23) in such a way that the outer contour (12) opens like a funnel toward the grinding surface (14), and the edge of the grinding surface (14) protrudes over the edge (15) formed by the lower side of the grinding flaps, and also protrudes the edge of the carrier (23).
5. The method according to one of the preceding claims,
   characterized in that
   the grinding flaps (24, 26) are adhesively bonded to the carrier (1, 23) in such a way that the outer contour (12) is tapered, and the edge of the grinding surface has nearly the same diameter as the edge formed by the lower side of the grinding flaps.
6. The method according to claim 1,
   characterized in that
   each of the strips is fed to a separate continued processing step.

Images