EP3651936B1 - Abrasive flap wheel for an angle grinder - Google Patents

Description

The invention relates to a flap disc for an angle grinder, comprising a substantially rotationally symmetrical carrier and grinding lamellae, which are arranged overlapping one another on the carrier, the grinding lamellae each having a shape of a trapezoid with a first trapezoidal side and a second trapezoidal side parallel thereto, and where the Length of the first trapezoidal side is smaller than the length of the second trapezoidal side, the carrier has a circular ring with an inner ring diameter and an outer ring diameter, the grinding flaps are arranged on the circular ring, the first trapezoidal side of the grinding flaps on the inner ring diameter and the second trapezoidal side of the Abrasive flaps are arranged on the outer ring diameter. The invention also relates to a method for producing such a flap disc.

Flap discs are known per se from the prior art. They are used on angle grinders for grinding and processing a wide variety of surfaces.

The flap discs usually comprise a carrier on which grinding flaps are arranged. The abrasive flaps are also known as "flaps".

The Figures 1a and 1b show a flap disc 101 according to the prior art, the Figure 1a a top view and the Figure 1b shows a perspective view obliquely from above. The flap disc 101 comprises a carrier 102 on which grinding flaps 103 are arranged so as to overlap one another.

The grinding flaps 103 have a rectangular shape. At the inner edge 130, the grinding lamellas are positioned most closely packed against one another, the packing density decreasing in the radial direction. As a result, the distance 114 between adjacent grinding flaps 103 decreases towards the outer edge. This creates gaps 131 between adjacent grinding lamellas 103. These gaps 131 have a disadvantageous effect on the service life of the flap disc 101, since the mobility of the grinding lamellae 103 in the grinding insert caused by the gaps 131 results in additional mechanical stress and vibration of the grinding lamellae 103 and further As a result, the abrasive lamellas 103 will wear out.

There have been attempts to counteract this disadvantage by clamping the flap discs together with shaping plates between each flap disc after the grinding lamellae 103 have been put on in the not yet hardened state of the adhesive, so that the grinding lamellae 103 are adjusted in the outer area, and the adhesive is hardened in this pack state undertakes. By inserting the shaping plates, however, the manufacturing process becomes less efficient, since the plates must also be inserted and, in the event of a thermal curing process of the adhesive, also have to be heated.

Another disadvantage of the prior art, especially when using rectangular flaps, is that the flap material is used up unevenly. The flaps are completely sanded off in the outer area of the flap disc, but less and less consumed in the direction of the hub of the flap disc, since complete wear requires an unusual, very flat grinding angle.

In the prior art, other shapes are used in addition to rectangular abrasive flaps. For example, the DE 20 2006 020 390 U1 a flap disc with triangular abrasive flaps.

In the DE 20 2010 008 898 U1 it should be noted that the DE 295 10 727 U1 would disclose a flap disc with trapezoidal abrasive flaps. In the DE 295 10 727 U1 itself no position is taken on this.

The U.S. 2,907,147 discloses a flap disc according to the preamble of claim 1.

The object of the present invention is to provide a flap disc which is improved compared to the prior art, in which the above-described problems have essentially been eliminated and which, in particular in the outer area, has no significant gaps between adjacent grinding lamellas. A further object of the invention is to provide a method for producing a flap disc improved in this way.

These objects are achieved by the features of independent claims 1 and 7.

In the case of the flap disc according to the invention, it is therefore provided that the ratio of the length of the second trapezoidal side to the length of the first trapezoidal side is essentially equal to the ratio of the outer ring diameter to the inner ring diameter.

These measures completely avoid gaps on the outer ring diameter. The fact that the ratio of the length of the second trapezoidal side to the length of the first trapezoidal side is essentially equal to the ratio of the outer ring diameter to the inner ring diameter, the gap formation due to the increase in diameter is compensated. The shape, ie the ratio of the second trapezoidal side (broad side) to the first trapezoidal side (narrow side) corresponds, according to the invention, to the increase in diameter between the inner ring diameter and the outer ring diameter.

It is irrelevant whether it is a trapezoid in general or an isosceles or a right-angled trapezoid in particular.

Because any gaps are avoided, there is no relative movement of adjacent grinding flaps during the grinding operation. Additional mechanical loads and vibrations of the grinding flaps are avoided. This significantly increases the service life of the flap disc.

Another advantage is that a greater amount of flap material can be used up due to wear and tear, since more flap material is available on the outer ring diameter.

According to particularly preferred embodiments, it is provided that the ratio of the length of the second trapezoidal side to the length of the first trapezoidal side or the ratio of the outer ring diameter to the inner ring diameter is 1 1.2 and 2.5, preferably 1.5 and ≤ 2.0.

By avoiding the formation of a gap, it is possible to design the grinding flap wheel in such a way that the grinding flap wheel has a grinding surface formed from the overlapping grinding lamellas, which can be brought into contact with a workpiece to be machined, the grinding flap wheel has an axis of rotation, the grinding surface in Is essentially flat, and the axis of rotation is aligned essentially normal to the grinding surface. This optimizes the grinding performance of the flap disc.

Furthermore, with the flap disc according to the invention it is possible to arrange the grinding flaps in such a way that the distance between two adjacent grinding flaps on the inner ring diameter is essentially the same as the distance on the outer ring diameter. This also has an advantageous effect on the grinding properties of the flap disc.

And finally, it is preferably provided that the abrasive lamellas each have a textile base on which abrasive grains are attached with the help of at least one binder, and / or that the carrier as a glass fiber reinforced plastic carrier, as a plastic carrier, as a natural fiber carrier or as Steel support is formed.

The binder can be synthetic resins. Cotton, polyester or mixed textiles made from both fibers are suitable as a textile underlay. Before applying the abrasive grains (e.g. normal corundum or zirconium corundum with a grain size of 24-120 mesh, or also SiC), a thin bonding layer of resin (basic bond), e.g. phenolic resin, should be applied. After the abrasive grains have been applied and the same has been electrostatically aligned, a size binder, which, in addition to resin, for example, can also contain fillers, can then be applied. In the case of very high-quality sanding belts, provision can be made for an additional application of a binding layer with a high filler content, which is also referred to as top size. For curing, one or more thermal curing processes are carried out.

The glass fiber reinforced plastic carrier (GRP carrier) can be produced by building up layers and pressing glass fiber fabrics pre-impregnated with phenolic resin, which are cured in the oven. If the carrier is designed as a plastic carrier, then it is advisable to injection-mold the carrier from thermoplastic, in which case glass fiber reinforced polyamide or ABS can be used, for example. Special variants are natural fiber carriers that can be used as reinforcement, for example hemp. And finally, the carrier can also be designed as a steel carrier, which is preferably an extruded or stamped thin steel carrier.

In the method for producing a flap disc according to the invention, the essentially rotationally symmetrical carrier is provided in a first method step, an adhesive, preferably an adhesive, is applied to the carrier in a second method step between the inner ring diameter and the outer ring diameter, and in a third Method step the grinding flaps, each of which has the shape of a trapezoid with a first trapezoidal side and a second trapezoidal side parallel to it, the length of the first trapezoidal side being smaller than the length of the second trapezoidal side and the ratio of the length of the second trapezoidal side to the length of the first Trapezoidal side is essentially the same as the ratio of the outer ring diameter to the inner ring diameter, arranged on the carrier in such a way that the grinding lamellas overlap and the first trapezoidal side of the grinding lamellae each on the inner ring diameter u nd the second trapezoidal side of the grinding flaps is arranged on the outer ring diameter.

It has been found to be beneficial that the grinding lamellae are initially placed one after the other in the course of the third process step with a third trapezoidal side, which connects the first trapezoidal side and the second trapezoidal side, on the carrier, with two adjacent grinding lamellae having a predetermined set distance relative to one another, and the abrasive flaps are then tilted in the direction of the carrier. The tilting of the grinding lamellae is particularly preferred in two stages, the grinding lamellae being slightly tilted in a first stage to specify a pressing direction, and the grinding lamellae being pressed in a second stage in the pressing direction onto the circular ring of the carrier. The predetermined setting distance can be achieved, for example, by rotating the carrier.

The Figure 2 shows schematically a manufacturing method according to the prior art. One half of a carrier 102 is indicated in cross section, with the carrier has an inclined shape. Instead, a straight beam can also be used. The axis of rotation 113 is indicated with a dot-dash line. A grinding belt 119 is fed via a transport device 127, which comprises a transport roller which is mounted rotatably about an axis of rotation 129. With the aid of a punching device 120, rectangular abrasive lamellas 103 are separated from this abrasive belt along separating lines 128 and placed on the carrier 102.

In contrast to this method according to the prior art, a preferred embodiment of the method according to the invention provides that the grinding lamellae, which are arranged on the carrier in the course of the third method step, are separated from a serrated grinding belt, preferably by means of a punching device, wherein the serrated shape results from a sequential arrangement of the trapezoidal shape of the grinding flaps, preferably wherein the grinding flaps are separated from the grinding belt on the first trapezoidal side or on the second trapezoidal side.

It has proven to be particularly advantageous in a first step to position one end of the serrated abrasive belt on the carrier, in a second partial step to separate a grinding flap from the serrated abrasive belt, and in a third partial step to separate the carrier and the serrated abrasive belt relative to one another by one to twist predetermined angle to achieve a predetermined set distance between two adjacent grinding lamellas, and to repeat the three partial steps until the carrier is equipped with a predetermined number of grinding lamellae, preferably the total loading time is less than 3 seconds. This means that the three sub-steps can be carried out in less than 0.1 seconds.

It is advisable here that the flap disc has an axis of rotation and the serrated grinding belt in a feed direction in the direction of the Carrier is advanced, the direction of advance includes an angle to the axis of rotation, and the angle is selected such that a third trapezoidal side of the grinding flaps, which connects the first trapezoidal side and the second trapezoidal side, is aligned essentially parallel to a setting surface of the carrier. In this context it is advantageous that the angle can be changed in order to be able to process different trapezoidal shapes and / or that the angle is essentially 90 °.

To achieve a predetermined feed path, a stop ring can be used which is positioned on the carrier and against which the end of the serrated abrasive belt strikes, and / or a feed device is used which advances the serrated abrasive belt by the respective feed path.

The serrated sanding belt can be separated from a sanding roller, the sanding roller having a width which corresponds to a multiple of the maximum width of the serrated sanding belt, preferably wherein at least two serrated sanding belts are separated from the sanding roller and the at least two serrated sanding belts are rotated 180 ° to each other are. As a result, the material of the grinding roller can be used almost without waste.

Fig. 1a

eine Fächerschleifscheibe gemäß dem Stand der Technik in einer Draufsicht von oben,

Fig. 1b

die Fächerschleifscheibe gemäß Figur 1a in einer perspektivischen Ansicht von schräg seitlich,

Fig. 2

eine schematische Darstellung eines Herstellungsverfahrens gemäß dem Stand der Technik,

Fig. 3a

einen Teil einer erfindungsgemäßen Fächerschleifscheibe gemäß einem ersten bevorzugten Ausführungsbeispiel mit trapezförmigen Schleiflamellen,

Fig. 3b

einen Teil einer erfindungsgemäßen Fächerschleifscheibe gemäß einem zweiten bevorzugten Ausführungsbeispiel mit Schleiflamellen in Form eines gleichschenkligen Trapezes,

Fig. 3c

einen Teil einer erfindungsgemäßen Fächerschleifscheibe gemäß einem dritten bevorzugten Ausführungsbeispiel mit Schleiflamellen in Form eines rechtwinkligen Trapezes,

Fig. 4a

eine Fächerschleifscheibe gemäß einem vierten bevorzugten Ausführungsbeispiel in einer Draufsicht von oben,

Fig. 4b

die Fächerschleifscheibe gemäß Figur 4a in einer perspektivischen Ansicht von schräg seitlich,

Fig. 5a

eine schematische Darstellung eines erfindungsgemäßen Herstellungsverfahrens gemäß einem ersten bevorzugten Ausführungsbeispiel in einer Seitenansicht,

Fig. 5b

eine schematische Darstellung des erfindungsgemäßen Herstellungsverfahrens gemäß dem ersten bevorzugten Ausführungsbeispiel in einer Draufsicht von oben,

Fig. 6a

eine schematische Darstellung eines erfindungsgemäßen Herstellungsverfahrens gemäß einem zweiten bevorzugten Ausführungsbeispiel in einer Seitenansicht,

Fig. 6b

eine schematische Darstellung des erfindungsgemäßen Herstellungsverfahrens gemäß dem zweiten bevorzugten Ausführungsbeispiel in einer Draufsicht von oben, und

Fig. 7

ein bevorzugtes Vorgehen zur Herstellung des gezackten Schleifbands in einer schematischen Darstellung.

Further details and advantages of the invention are explained in more detail below on the basis of the description of the figures with reference to the drawings. Show in it:

Fig. 1a

a flap disc according to the prior art in a top view from above,

Figure 1b

the flap disc according to Figure 1a in a perspective view obliquely from the side,

Fig. 2

a schematic representation of a manufacturing process according to the prior art,

Fig. 3a

a part of a flap disc according to the invention according to a first preferred embodiment with trapezoidal grinding flaps,

Figure 3b

a part of a flap disc according to the invention according to a second preferred embodiment with abrasive flaps in the form of an isosceles trapezoid,

Figure 3c

a part of a flap disc according to the invention according to a third preferred embodiment with grinding flaps in the form of a right-angled trapezoid,

Figure 4a

a flap disc according to a fourth preferred embodiment in a top view from above,

Figure 4b

the flap disc according to Figure 4a in a perspective view obliquely from the side,

Figure 5a

a schematic representation of a production method according to the invention according to a first preferred embodiment in a side view,

Figure 5b

a schematic representation of the production method according to the invention according to the first preferred embodiment in a plan view from above,

Figure 6a

a schematic representation of a production method according to the invention according to a second preferred embodiment in a side view,

Figure 6b

a schematic representation of the production method according to the invention according to the second preferred embodiment in a plan view from above, and

Fig. 7

a preferred procedure for producing the serrated abrasive belt in a schematic representation.

The Figures 1a, 1b and 2 which show the prior art have already been described above.

The Figures 3a, 3b and 3c show preferred embodiments of a flap disc according to the invention, only two grinding flaps 3 being shown.

The basic structure is the same in each case: the flap disc has an essentially rotationally symmetrical carrier 2 and abrasive flaps 3, which are arranged on the carrier 2 so as to overlap one another. The grinding lamellae 3 each have the shape of a trapezoid with a first trapezoidal side 4 and a second trapezoidal side 5 parallel thereto, the length 6 of the first trapezoidal side 4 being smaller than the length 7 of the second trapezoidal side 5.

The two trapezoidal sides 4 and 5 are connected to one another by two further trapezoidal sides 17 and 31.

The carrier 2 has a circular ring 9 with an inner ring diameter 10 and an outer ring diameter 11. The grinding flaps 3 are arranged on the circular ring 9, the first trapezoidal side 4 of the grinding flaps 3 being arranged on the inner ring diameter 10 and the second trapezoidal side 5 of the grinding flaps 3 being arranged on the outer ring diameter 11. The grinding lamellae 3 can protrude somewhat beyond the circular ring 9 or the carrier 2.

The carrier 2 further comprises a central bore 8, through the center 30 of which the axis of rotation of the flap disc runs. The hole 8 is used to connect the flap disc to a rotary drive of an angle grinder.

The exemplary embodiments differ in that the grinding flaps 3 in the case of Figure 3a generally have the shape of a trapezoid, in the case of Figure 3b have the special shape of an isosceles trapezoid and in the case of the Figure 3c the special shape of a right-angled trapezoid exhibit. As already stated, the trapezoidal shape is not important. It is essential that the ratio of the length 7 of the second trapezoidal side 5 to the length 6 of the first trapezoidal side 4 is essentially equal to the ratio of the outer ring diameter 11 to the inner ring diameter 10.

Depending on the width 25 of the grinding lamellae 3 and the inner and outer ring diameter 10 or 11, there are geometrically determined, discrete quotients which, when applied to the trapezoidal flap shape, completely avoid the disadvantageous air gaps. According to preferred embodiments, these are: Width 25 of the grinding flaps 3 in mm Outer ring diameter 11 or nominal diameter of the flap disc 1 in mm Inner ring diameter 10 in mm Ratio 11/10 or 7/6 25th 100 50 2.00 25th 115 65 1.77 25th 125 75 1.67 28 125 69 1.81 30th 125 65 1.92 30th 150 90 1.67 35 150 80 1.88 30th 178 118 1.51 35 178 108 1.65

In these embodiments, the ratio of the length 7 of the second trapezoidal side 5 to the length 6 of the first trapezoidal side 4 or the ratio of the outer ring diameter 11 to the inner ring diameter 10 is 1.5 and 2.0.

The Figures 4a and 4b show a further embodiment of the flap disc 1 according to the invention. In particular from FIG Figure 4b It can be seen that the grinding surface 12 formed from the overlapping grinding lamellas 3, which can be brought into contact with a workpiece to be processed, is essentially flat, and the axis of rotation 13 is oriented essentially normal to the grinding surface 12.

The distance between two adjacent grinding flaps 3 on the outer ring diameter 11 is provided with the reference symbol 14. This distance is essentially equal to the distance between two adjacent grinding lamellae 3 on the inner ring diameter 10.

It can also be seen that the abrasive lamellas 3 each have a textile base 15 to which abrasive grains 16 are attached with the aid of at least one binding agent.

The Figures 5a and 5b show a first preferred embodiment of the method according to the invention for producing a flap disc. In this case, the essentially rotationally symmetrical carrier 2 is provided in a first method step. In the case shown, it is an inclined carrier 2, in which the outer area of the carrier runs inclined with respect to the axis of rotation 13 and slopes down. However, a carrier 2 that is straight can also be used just as well.

In order to be able to equip both types of carrier 2 with the method, it is advantageous that the feed device 27 and punching device 20 described below can be rotated relative to the carrier 2. This is indicated by the arrow 32. The rotation of the feed device 27 and the punching device 20 relative to the carrier 2 also serves to be able to set grinding flaps with different trapezoidal angles.

In other words, the serrated sanding belt 19 is advanced in a feed direction 34 in the direction of the carrier 2, the feed direction 34 enclosing an angle 35 to the axis of rotation 13, and the angle 35 can be selected such that the third trapezoidal side 17 of the grinding flaps 3, which the connects the first trapezoidal side 4 and the second trapezoidal side 5, is oriented essentially parallel to a setting surface 36 of the carrier 2.

In a second process step, between the inner ring diameter 10 and the outer ring diameter 11, i. H. in the circular ring 9, an adhesive is applied to the carrier 2.

And finally, in a third process step, the grinding flaps 3 are arranged on the carrier 2 in such a way that the grinding flaps 3 overlap each other and the first trapezoidal side 4 of the grinding flaps 3 each on the inner ring diameter 10 and the second trapezoidal side 5 of the grinding flaps 3 each on the outer ring diameter 11 is arranged.

In the course of the third method step, the grinding lamellae 3 are first placed one after the other with a third trapezoidal side 17, which connects the first trapezoidal side 4 and the second trapezoidal side 5, on the carrier 2, with two adjacent grinding lamellas 3 having a predetermined set distance 18 relative to one another.

As in particular from the Figure 5a As can be seen, the grinding lamellae 3, which are arranged on the carrier 2 in the course of the third process step, are separated from a serrated grinding belt 19 by means of a punching device 20, the serrated shape of the grinding belt 19 resulting from a sequential arrangement of the trapezoidal shape of the grinding lamellae 3. In the case shown, the grinding lamellae 3 are cut off on the second side 5 of the trapezoid.

In detail, in order to position an abrasive flap 3 on the carrier 2, an end 23 of the serrated abrasive belt 19 is positioned on the carrier 2 in a first substep. In a second partial step, a grinding lamella 3 is separated from the serrated grinding belt 19, specifically along a separating line 28 which corresponds to part of the second trapezoidal side 5 of the grinding lamella 3 to be separated. In a third sub-step, the carrier 2 and the serrated grinding belt 19 are rotated relative to one another by a predetermined angle 24 to achieve the predetermined set distance 18 between two adjacent grinding lamellae 3 (cf. Figure 5b ). These three sub-steps take less than 0.1 second.

The three partial steps are repeated until the carrier 2 is equipped with the predetermined number of grinding lamellae 3. The loading time for all grinding lamellas 3 is less than 3 seconds.

After all the grinding lamellae have been set, the grinding lamellae 3 are tilted in the direction of the carrier 2. The tilting of the grinding lamellae 3 takes place in two stages, the grinding lamellae 3 being slightly tilted in a first stage to specify a pressing direction, and the grinding lamellae 3 being pressed onto the circular ring 9 of the carrier 2 in a second stage in the pressing direction. A pressure bell, for example, is used for this purpose.

By a certain feed path 25, which corresponds to the width of the grinding lamellae 3 (see also Figures 3a to 3c ), a feed device 27 in the form of one or more transport rollers, which can be rotated about an axis of rotation 29, is used. This advancing device 27 advances the serrated grinding belt 19 by the advancing path 25.

As an alternative or in addition to this, a stop ring 26 can also be used which is positioned on the carrier 2 and against which the end 23 of the serrated abrasive belt 19 strikes. This embodiment of the method according to the invention is shown in Figures 6a and 6b shown.

In both cases, the serrated abrasive belt 19 is advanced essentially transversely to the axis of rotation 13 in the direction of the carrier 2.

To produce the serrated abrasive belt 19 it can, as in Figure 7 It can be provided that the serrated abrasive belt 19 is cut out of a grinding roller 21, the grinding roller 21 having a width 22 which is a multiple of the maximum width 7 (compare for example Figure 5a ) corresponds, with two adjacent serrated grinding belts 19 being rotated by 180 ° relative to one another. In this way, the grinding belts 19 can be separated from the grinding roller 21 with almost no waste. Only the outer edge strips 33 have to be disposed of as waste.

To cut out the serrated grinding belts 19, ring-shaped knives with the desired serrated shape are preferably used. Alternatively, the strips can also be separated with the aid of laser radiation or the like.

The individual strips are rolled up and can now be fed to the setting and punching process for the filling of a carrier body with grinding lamellas.

Claims (15)

1. A flap grinding disc (1) for an angle grinder, comprising a substantially rotationally symmetrical carrier (2) and abrasive flaps (3) which are arranged in mutually overlapping relationship on the carrier (2), wherein the abrasive flaps (3) are each in the shape of a trapezium with a first trapezium side (4) and a second trapezium side (5) parallel thereto, and wherein the length (6) of the first trapezium side (4) is smaller than the length (7) of the second trapezium side (5), the carrier (2) has a circular ring (9) with an inner ring diameter (10) and an outer ring diameter (11), the abrasive flaps (3) are arranged on the circular ring (9), wherein the first trapezium side (4) of the abrasive flaps (3) is respectively arranged at the inner ring diameter (10) and the second trapezium side (5) of the abrasive flaps (3) is respectively arranged at the outer ring diameter (11), characterised in that the ratio of the length (7) of the second trapezium side (5) to the length (6) the first trapezium side (4) is substantially equal to the ratio of the outer ring diameter (11) to the inner ring diameter (10).
2. The flap grinding disc (1) according to claim 1 wherein the ratio of the length (7) of the second trapezium side (5) to the length (6) of the first trapezium side (4) or the ratio of the outer ring diameter (11) to the inner ring diameter (10) ≥ 1.2 and ≤ 2.5, preferably ≥ 1.5 and ≤ 2.0.
3. The flap grinding disc (1) according to claim 1 or 2 wherein the flap grinding disc (1) has a grinding surface (12) which is formed from the overlapping abrasive flaps (3) and can be brought into contact with a workpiece to be machined, the flap grinding disc (1) has an axis of rotation (13), the grinding surface (12) is substantially flat, and the axis of rotation (13) is oriented substantially normal to the grinding surface (12).
4. The flap grinding disc (1) according to one of claims 1 to 3 wherein the spacing between two adjacent abrasive flaps (3) at the inner ring diameter (10) is substantially equal to the spacing (14) at the outer ring diameter (11).
5. The flap grinding disc (1) according to one of claims 1 to 4 wherein the abrasive flaps (3) each have a textile base (15) to which abrasive grains (16) are attached with the aid of at least one bonding agent.
6. The flap grinding disc (1) according to one of claims 1 to 5 wherein the carrier (2) is in the form of a glass fibre-reinforced plastic carrier, a plastic carrier, a natural fibre carrier or a steel carrier.
7. A method of producing a flap grinding disc (1) according to one of the preceding claims, wherein in a first method step the substantially rotationally symmetrical carrier (2) is provided, in a second method step an adhesive, preferably a glue, is applied to the carrier (2) between the inner ring diameter (10) and the outer ring diameter (11), and in a third method step the abrasive flaps (3) which are each in the shape of a trapezium with a first trapezium side (4) and a second trapezium side (5) parallel thereto, wherein the length (6) of the first trapezium side (4) is smaller than the length (7) of the second trapezium side (5) and the ratio of the length (7) of the second trapezium side (5) to the length (6) of the first trapezium side (4) is substantially equal to the ratio of the outer ring diameter (11) to the inner ring diameter (10), are arranged on the carrier (2) in such a way that the abrasive flaps (3) overlap each other and the first trapezium side (4) of the abrasive flaps (3) is respectively arranged at the inner ring diameter (10) and the second trapezium side (5) of the abrasive flaps (3) is respectively arranged at the outer ring diameter (11).
8. The method according to claim 7 wherein the abrasive flaps (3) in the course of the third method step are first placed one after the other on the carrier (2) with a third trapezium side (17) which connects the first trapezium side (4) and the second trapezium side (5), wherein two adjacent abrasive flaps (3) have a predetermined set spacing (18) relative to one another, and the abrasive flaps (3) are then tilted in the direction of the carrier (2).
9. The method according to claim 8 wherein tilting of the abrasive flaps (3) takes place in two stages, wherein the abrasive flaps (3) are slightly tilted in a first stage in order to predetermine a pressing direction, and wherein the abrasive flaps (3) in a second stage are pressed in the pressing direction on to the circular ring (9) of the carrier (2).
10. The method according to one of claims 7 to 9 wherein the abrasive flaps (3) which are arranged on the carrier (2) in the course of the third method step are separated from a serrated abrasive belt (19), preferably by means of a punching device (20), wherein the serrated shape results from a sequential arrangement of the trapezium shape of the abrasive flaps (3), preferably wherein the abrasive flaps (3) are separated from the abrasive belt (19) at the first trapezium side (4) or the second trapezium side (5).
11. The method according to claim 10 wherein the serrated abrasive belt (19) is separated from an abrasive roll (21), the abrasive roll (21) being of a width (22) which corresponds to a multiple of the maximum width (7) of the serrated abrasive belt (19), preferably wherein at least two serrated abrasive belts (19) are separated from the abrasive roll (21) and the at least two serrated abrasive belts (19) are rotated through 180° relative to one another.
12. The method according to claim 10 or claim 11 wherein in a first sub-step an end (23) of the serrated abrasive belt (19) is positioned on the carrier (2), in a second sub-step an abrasive flap (3) is separated from the serrated abrasive belt (19), in a third step the carrier (2) and the serrated abrasive belt (19) are rotated relative to each other by a predetermined angle (24) to achieve a predetermined set spacing (18) between two adjacent abrasive flaps (3), and the three sub-steps are repeated until the carrier (2) is fitted with a predetermined number of abrasive flaps (3), preferably the total fitting time being less than 3 seconds.
13. The method according to one of claims 10 to 12 wherein the flap grinding disc (1) has an axis of rotation (13) and the serrated abrasive belt (19) is advanced in a feed direction (34) towards the carrier (2), the feed direction (34) includes an angle (35) to the axis of rotation (13), and the angle (35) is so selected that a third trapezium side (17) of the abrasive flaps (3), which connects the first trapezium side (4) and the second trapezium side (5), is oriented substantially parallel to a setting surface (36) of the carrier (2).
14. The method according to claim 13 wherein the angle (35) is variable and/or is substantially 90 °.
15. The method according to claim 13 or claim 14 wherein a stop ring (26) is used to achieve a predetermined feed travel (25), which is positioned on the carrier (2) and against which the end (23) of the serrated abrasive belt (19) bears, and/or a feed device (27) is used, which respectively feeds the serrated abrasive belt (19) by the feed travel (25).

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