EP1068048B1 - Plated grinding tool - Google Patents

Description

Field of the Invention

The invention relates to a flap grinding tool that is symmetrical an axis of rotation is formed with a plurality of on the Circumference and / or end faces arranged grinding lamella, one Carrier body on which the grinding flaps are attached, and one Device for connecting the flap grinding tool to a Drive device, wherein the carrier body at least one has rotationally symmetrical lateral surface on which the grinding flaps are at least partially attached, and a quick release device for connecting a flap grinding tool to a Drive device and a set of a flap grinding tool and a quick release device.

Such flap grinding tools are preferably used for Surface processing, especially in mold or body construction used. Special advantages are the elastic adjustment of the Grinding lamellas on the workpiece contour and the cool grinding. Through the Lamella arrangement results in a very long service life Tools.

Background of the Invention

Sanding belts with a lamellar design are made, for example GB 938,223 A1 known per se. DE 85 23 363 U1 discloses a such grinding belt on a hollow cylinder with the dimensions of a Steel strip coils to tension when winding steel strip Pressure rollers on the rewinder to create print marks eliminate before this affects the surface quality of the Can lead steel strip.

Flap grinding tools are known in the art to in particular to machine profiled workpiece surfaces without the Damage the surface due to scoring and the like. Especially in tool and mold making, such flap grinding tools are included radial trimmings made of grinding flaps for fine grinding and polishing work widely used on larger radii.

Such sander for circumferential grinding usually exist from a shaft with which the grinding tool e.g. in a drill chuck can be clamped, the profiled and with a rigid core of the Sander is glued or pressed. At its core are the Slats radially by gluing in grooves or tangentially in one Adhesive or potting layer attached. Such sander are also commercially available, for example in US 4,090,333 A. described and an embodiment for screw mounting on a Shaft is also described in DE-GM 1 986 971.

From US 3,406, 488 A a sander is known in which a number of grinding flaps in a radial arrangement embedded in a sleeve are made of a relatively hard resin material. This sleeve is made of a resin material with a sheet metal cover connected, which has a bore for receiving a drive shaft. The sheet metal lid also has an in on its outer peripheral edge Direction on the sleeve-shaped bead, which in corresponding grooves of the grinding flaps engages to provide positive locking against to form a radial flyout of the slats if they come out of the Loosen resin bond. The disclosure of US 3,406,488 A is concerned essentially with the advantages of introducing certain elastomers into the grooves of the grinding lamella, where it fits the beads on the lids interact. This is the mechanical life of the Flap grinders are increased to make fractures or decay more comparable Avoid flap grinders that are essentially due to overdetermination the clamping points will be attributable.

Furthermore, an execution of such a sander is also on the market radial grinding flap known in which the core in which the Drive shaft is inserted, is arranged recessed at the front the radially inserted grinding flaps also on the front To bring workpiece. Such an execution is also in Tool catalog 93/94 from Hch. Perschmann GmbH, Braunschweig, described.

From DE 40 07 928 A1 and EP 0 446 626 A1 are grinding sleeves for the Circumferential grinding known to improve profitability when using such sander on a reusable Sanding belt bodies are clamped. Such includes Sanding belt body the shaft for connection to a drive machine as well as a rubber body arranged between cones, which by tensioning the cone defines the grinding sleeve radially. Such a commercial one Sanding belt body is, for example, in the tool catalog 93/94 from Hch. Perschmann GmbH, Braunschweig.

For processing welds, for surface grinding, for Rust removal and cast cleaning are flap discs for use Angle grinders are known in which the trimming consists of grinding flaps is arranged on the face of a disc. Such disks are for example commercially available under the name horse Polifan and in the tool catalog 93/94 from Hch. Perschmann GmbH, Braunschweig, described. These discs consist of a carrier plate Glass fiber fabric mats, the axial face with grinding lamella are equipped and a usual mounting hole in the middle Have attachment to the output spindle of an angle grinder. Glass fiber fabric mats are used so that the plate with the Slats wear evenly when the tool is switched on and one permits complete consumption of the slats.

Such flap discs for use on angle machines after The above type are also known from DE 195 11 004 C1. There is as Special feature highlighted that the carrier plate made of wood shavings or Wood chips are said to consist of a resin binder hardened phenolic resin and melamine resin should be embedded and thus form a wood fiber reinforced plastic. By choice the material is said to be particularly inexpensive to manufacture result. From an environmental point of view, however, may point straight this choice of material of the carrier plate, which in any case according to consumption the flap disc remains as waste, one currently unresolved situation regarding the recyclability of the wood composite on.

From 'Patent Abstracts of Japan' is a reference to JP 60 094271 A. Polishing wheel known, which is essentially the one previously used for grinding wheels described structure, but instead of Sanding flap sections of a textile material for polishing are attached to using similar machines and machining operations Allow polishing of surfaces.

From DE 89 03 423 U1 a grinding flap disc is used known with angle grinders, in the case of a disc-shaped carrier a number of grinding flaps is arranged on both end faces, on the one hand to process walls of relatively narrow grooves enable and on the other hand an increased service life of the disc to get through reversibility. For this, they are each out assembling shingle-like grinding lamellae Usable areas oriented in opposite directions.

From US 5,722,881 A a flap grinding tool with a trim is attached Known grinding flaps on the radial circumference. Here are the Grinding flaps directly onto the radial with the help of an epoxy resin Glued outside of a disc-shaped carrier body, the disc-shaped carrier body made of an inner sheet metal disc and one outer fiberglass pane. For attachment to one Commercial angle grinder is with the steel disc in the middle provided a weld nut, which over the through the outside of the Formed surfaces of the grinding flaps protrude.

Furthermore, yet another embodiment is described in which the Carrier body consists of a metal pot, except for a central one disc-shaped part with a flat offset a flanged has radially outer edge, on the in turn by means of Epoxy resin the grinding flaps are glued on. This embodiment is intended for mounting on an outstanding stub shaft, e.g. for use on a stationary grinding machine.

All of these known flap grinding tools have special ones Areas of application and fulfill their function. Still is the stake such tools with a relatively high cost in the manufacture connected, and by the short in relation to the total material use Service life creates a relatively high proportion of waste when used. Because of the high loads caused by centrifugal and tensile forces the slats have so far been reduced in manufacturing costs, to ensure operational safety.

A good example of this is described in DE 25 01 589. There becomes Avoiding large amounts of waste proposed a solution in that that with a rotating grinding tool in a very expensive manufactured hub a total of 6 individual packages with one each A large number of interchangeable grinding or emery sheets are used can be. The sanding or emery sheets are used a package through a circularly bent retaining pin held by appropriate punched holes in part of the Sanding or emery sheets extends through and outside the Recesses for the packages in a groove provided in the hub supports and so against the packets of sanding or emery sheets Flying away by the centrifugal force secures when operating the tool. Due to the design principle of this tool is an extremely high one Manufacturing effort for numerous millings for recesses and grooves required. Furthermore, the tool consists of a variety of Individual parts that require a relatively complicated assembly and thus involve a certain risk of accident if the users themselves try to replace used sanding sheets. Still remains also a not insignificant part of the sanding sheets as residual waste, because the holes in the sanding sheets to accommodate the Keep the support pin some distance from the end of the sanding sheet so that the holes do not tear out and the sanding sheets in the Operation fly away.

Furthermore, due to the design principle, it is not possible Distribute sanding sheets evenly over the circumference, since between Two sanding sheet packs of wall areas remain in the hub need to absorb the forces from the retaining pin and into the hub initiate.

It is also in connection with the tool disclosed there only a mounting flange with an internal thread for Mounting on a drive shaft disclosed. Lack of details from the point of view of the person skilled in the art, this may only be the case for such persons Applications deal with the usual metric threads of size M 14.

The invention is therefore based on the object, flap grinding tools and to provide appropriate tools in which without Reduction of operational security a more economical, in terms waste use, improved use and wider scope is possible.

Description of the invention

This object is achieved according to the invention by a flap grinding tool according to claim 1.

Through the training according to the invention, the manufacture of a such a tool without functional disadvantages and also simplify the Reduce waste through consumption. In particular, problems can arise with regard to the dimensional accuracy of such a tool can be avoided, which is more conventional due to the springback of the flanged edge during deep drawing Carrier bodies exist and because of the rolling of the raw material existing anisotropy of the semi-finished product are unavoidable. Through the The grinding lamella can be divided into several parts easy to position in a sufficiently precise orientation. To Consumption can be the parts of the invention Separate the flap grinding tool and dispose of it separately or at least partially return to the production cycle.

In a preferred embodiment, the disc is in the region of the Contact surface cranked so far that the contact surface axially outside one circumscribed by the outer edges of the grinding flaps Rotating body is arranged. This makes it possible Tool according to the invention without adapters or spacers that always require additional set-up times and the risk of accidents increase, use particularly well on hand-held angle grinders. thereby expanding your economic application.

In an expedient embodiment is an inventive one Flap grinding tool characterized in that the carrier body a plastic, preferably a fiber-reinforced plastic and / or that the carrier body is made of aluminum or steel. It is advantageous if the disc is made of a plastic, preferably a fiber-reinforced plastic, or is made Washer is made of aluminum or steel.

In terms of production technology, it is advantageous if the carrier ring consists of one Plastic, preferably a fiber-reinforced plastic, a Hard rubber or a hard paper is made, or that the carrier ring is made of aluminum or steel.

To reduce manufacturing costs and optimize the Damping behavior of the flap grinding tool can be advantageous be if the carrier ring and washer are made of different materials are made.

Especially with regard to the variety of options to adapt to various drives, it may be appropriate if the carrier ring and The pane is connected to one another by pressing, gluing or welding are. The special advantages can also be different Use materials particularly well. After use, the individual Separate and dispose of parts separately or recycle.

In a particularly expedient embodiment, the pane is through an automatic eccentric or centrifugal clamping device educated. In such an embodiment, the consumable part keep a tool according to the invention particularly low and particularly replace quickly, in particular without the against incorrect operation Loosen safety-critical chucks or the like every time and to have to fasten again.

For use on stationary machines and when processing large ones Surfaces can be used to take advantage of the advantages of the invention be useful if the carrier body of an inventive Flap grinding tool has several discs.

For the processing of molds in mold making in particular Tried to be particularly efficient when trying one Flap grinding tool of the type mentioned or described above Type is characterized in that grinding flaps on both Circumference, as well as on an end face of the flap grinding tool are arranged. Compared to the previously known way, radially The arranged lamellae simply allow it to project axially Execution according to the invention a simultaneous scope and Forehead grinding with comparable performance features both in terms of grinding performance and tool life. Also exists against the known tool training the great advantage that practically no There is a risk of slat parts breaking out as the slats here are only claimed in one direction in which they are for one appropriate load are designed, namely tensile load and not on bend.

The use of materials in the consumables can be further reduce by a flap grinding tool of the type mentioned at the beginning, in which the carrier body a device for connecting the Flap grinding tool with a quick clamping device for Connection of the flap grinding tool to a drive device having.

With such training, the set-up times at Replacement of such a tool can be reduced considerably, which is a significant advantage in terms of an economic Use of such tools entails. It also increases the risk of Malfunctions and accidents through the use of such a tool significantly reduced, as a proper seat of the tool visually is verifiable, in contrast to the application of sufficient Previously known clamping force based attachment by chuck or similar.

In a particularly preferred embodiment, one according to the invention Lamellar grinding tool, characterized in that the device for Connection of the flap grinding tool with a Quick release device is adapted to part of a bayonet or To form a bayonet connection. Such a connection allows one particularly safe and quick connection of the tool to a Drive.

But it can also be useful if the device for connection of the flap grinding tool with a quick clamping device or multi-start screw or nut thread, in particular, if the thread is a high-helix thread and / or the thread is a rectangular or trapezoidal thread.

A flap grinding tool of the type described above can be produced particularly easily if the device for Connection of the flap grinding tool to a drive device comprises a shaft connected to the carrier body in a rotationally fixed manner and the Carrier body consists of a synthetic resin body, in which the Sanding flaps and the shaft are directly embedded. It is also particularly advantageous with regard to disposal after use because gives a much easier way of separating materials and so the disposal effort is reduced and at least partially Recycling of the components of the tool is possible.

The above applies in particular if the carrier body by at least partial shedding of one positioned between each other Sanding flaps and the shaft formed space with a plastic or synthetic resin and / or the carrier body at least partially a hard paper (fiber material).

The advantages of a preferred embodiment of the invention can be Use particularly well with a quick release device for connection of a flap grinding tool with a drive device in which the quick release device is designed to work with a corresponding Flap grinding tool to cooperate, especially when the disc is such a quick release device, and in a set of one such a flap grinding tool and such Quick clamping device.

Description of preferred embodiments

Fig. 1

ein erfindungsgemäßes Lamellenschleifwerkzeug mit radial angeordneten Schleiflamellen:

Fig. 2

ein erfindungsgemäßes Lamellenschleifwerkzeug mit radial und stirnseitig angeordneten Schleiflamellen;

Fig. 3

ein Lamellenschleifwerkzeug, bei dem ein Schaft zum Antrieb des Werkzeugs und die Schleiflamellen direkt in einen Kunstharzkörper eingebettet sind;

jeweils im Teilschnitt;The invention will be explained in more detail below with reference to exemplary embodiments shown in the drawings. Show it:

Fig. 1

an inventive flap grinding tool with radially arranged grinding flaps:

Fig. 2

an inventive lamellar grinding tool with radially and frontally arranged grinding lamellae;

Fig. 3

a flap grinding tool in which a shaft for driving the tool and the grinding flaps are embedded directly in a synthetic resin body;

each in partial section;

Fig. 4

ein erfindungsgemäßes Lamellenschleifwerkzeug mit radial angeordneten Schleiflamellen, bei dem die Scheibe des Trägerkörpers durch eine selbsttätig wirkende Exzenter- oder Fliehkraftspannvorrichtung gebildet ist (teilweise in schematischer Darstellung).

This tool design is not the subject of the invention.

Fig. 4

an inventive lamellar grinding tool with radially arranged grinding lamellae, in which the disk of the carrier body is formed by an automatically acting eccentric or centrifugal force clamping device (partly in a schematic representation).

1 shows a flap grinding tool according to the invention, which is symmetrical about an axis of rotation 1 and a Has a plurality of grinding flaps 2 arranged on the circumference. The Sanding flaps 2 are in a conventional manner, e.g. B. by means of a Adhesive 3 attached to a carrier body 4a, 4b.

The carrier body comprises, for example, a deep-drawn one Metal disc 4a, which as a device for connecting the Flap grinding tool with a drive device a hole 5 for Inclusion of a screw fastening of a common drive spindle having. In the area of the outer circumference of the metal disc 4a is a Carrier ring 4b attached. On the outside of the carrier ring 4b is one jacket surface 6 oriented approximately cylindrical to axis of rotation 1 formed on which the adhesive 3 for fastening the grinding flaps 2 is applied, i.e. the lateral surface 6 is approximately 0 ° to the axis of rotation 1 inclined.

As can be clearly seen in FIG. 1, the metal disc 4a comprises a Central element 7, which is essentially radial to the axis of rotation 1 extends. Around the central hole 5 there is a contact surface 8 for contact a drive device. This is the metal disc 4a cranked, resulting in a mechanically particularly stable Execution results. As shown, the disc 4a is so far cranked that the contact surface 8 axially outside of one by the Outer edges of the grinding lamella 2 circumscribed body is arranged. As a result, such a tool according to the invention can also be used especially good on hand-held grinders, especially Angle grinders, are used, which extends their scope extended. In particular, it is avoided that the radially outside slats 2 with a conventional protective hood commercially available angle grinder can collide and the user you might be tempted to remove the protective cover.

To get a clean finish down to the corners of the workpiece, it is advantageous if, as shown, at least part of the Grinding flaps 2 axially at least on one side over the limit which protrude at least one lateral surface 6, in particular if the Sanding flaps 2 at least 3 mm beyond the limit of at least protrude a lateral surface 6.

As an alternative to the illustrated embodiment, a lamellar grinding tool according to the invention of the carrier body Plastic. preferably comprise a fiber-reinforced plastic and / or that the carrier body be made of aluminum or steel. It is advantageous here. if the disc 4a is made of a plastic, preferably a fiber-reinforced plastic, or is made Washer 4a is made of aluminum or steel.

In terms of manufacturing technology, it can be favorable if the carrier ring 4b made of a plastic, preferably a fiber-reinforced plastic, a hard rubber or a hard paper is made, or that the Carrier ring 4b is made of aluminum or steel.

In the embodiment shown, disc 4a and carrier ring 4b made of weldable materials, e.g. Steel or Aluminum. A weld seam for the connection of disc 4a and carrier ring 4b is denoted by 4c, which, depending on the expediency, is circumferential or only can be formed in sections or as spot welding.

For certain areas of application, it can reduce the Manufacturing costs and to optimize the damping behavior of the Flap grinding tool can be advantageous if the carrier ring 4b and Washer 4a are made of different materials. In particular with regard to the variety of variants to adapt to different drives it may be useful if the carrier ring and disc together are connected by pressing or gluing.

The flap grinding tool shown in Fig. 2 has for Processing especially of molds in mold making when trying highlighted particularly efficiently. Here, grinding flaps 2 are both on the circumference 9, as well as on a front lateral surface 10 of the Flap grinding tool arranged. Compared to the previously known Way, radially arranged lamellae 2 simply protrude axially let, the inventive design allows a simultaneous Circumferential and forehead grinding with comparable performance features both in terms of grinding performance and tool life. Also exists the great advantage over the known tool design that there is practically no risk of slat parts breaking out, since the slats are only stressed in the direction of pull in which they are designed for a corresponding load.

Compared to the illustrated embodiment, it has also proven to be advantageously exposed on the radially outer circumference arranged grinding flaps 2 on the front or axially arranged to survive grinding flaps 2.

The lamellar grinding tool shown in Fig. 3 leaves are particularly easy to manufacture because a shaft 11 as a device for connecting the flap grinding tool to a Serves drive device that is rotatably connected to the carrier body is and the carrier body consists of a synthetic resin body 12, in the the grinding flaps 2 and the shaft 11 are directly embedded. This is also special with regard to disposal after use advantageous because there is a much easier way of Material separation results and thus the disposal effort is reduced and an at least partial recycling of the components of the Tool is possible.

As can be clearly seen in FIG. 3, the carrier body is through at least partially shedding one between them positioned grinding flaps 2 and the shaft 11 formed space with a plastic or synthetic resin. Has been particularly suitable the use of hard paper (fiber material) emerged.

FIG. 4 shows a particularly advantageous embodiment of the invention shown schematically and partially simplified. This is suitable especially for use on a stationary grinding machine in the Production. The grinding flaps are 2 (only a few of them are excellent) as in the other embodiments by means of adhesive 3 on a carrier ring 4b, e.g. advantageously from a hard paper, attached. The carrier ring 4b is in operation radially outside by one Centrifugal or eccentric clamping device arranged in place the disc 4a occurs in the other described embodiments.

This centrifugal force or eccentric clamping device can for example comprise a turned aluminum core 13 which has a hole 5 for receiving a mandrel or otherwise for coupling with a Drive can be designed appropriately. The aluminum core 13 or one Corresponding component made of any other suitable material can shaped like a hub. Radially around the core 13 is in the Embodiment shown vulcanized a rubber ring 14. The Rubber ring 14 has numerous slots 15 from its circumference provided, the slots 15 not to the radially inner edge of the Rubber ring 14 range and are arranged inclined to the radius.

If the aluminum core 13 is set in rotation with the rubber ring 14, strive for the segments 16 formed between two slots 15 due to the centrifugal forces that occur to straighten up radially and thus to enlarge the outer diameter of the rubber ring 14. Is located on the rubber ring 14 a support ring 4b pushed thereon, this becomes automatically tensioned by the clamping forces that occur.

Therefore, during production, the grinding flaps 2 equipped carrier rings 4b slightly axially when the machine is at a standstill pull off and slide on, which results in a tool change minimal setup times result. In addition, this is particularly safe because none Loosened screw connections of mandrels or chucks and again must be tightened and thereby neither forget anything nor wrong can be made.

Depending on the orientation of the only shown schematically in Figure 4 Abrasive flaps 2 to the arrangement of the segments 16 leads to the application a load moment, e.g. through grinding work, through the friction between Rubber ring 14 and carrier ring 4b to reinforce the clamping and therefore an increase in the transmissible torque, e.g. for one To prevent the flap grinding tool from blocking on the workpiece. However, it can also be expedient to mount the carrier ring 4b in such a way that that the orientation of grinding lamellae 2 and slots 15 in the same direction is, which when increasing the load torque on the scope of Carrier ring 4b by an advance of the rubber ring 14 Swiveling the segments 16 inwards and relative to the carrier ring 4b Reduction of the clamping force results. This is similar to a slip clutch Characteristic can e.g. increased to certain applications Accident protection can be used.

An embodiment of a is not shown in the figures Flap grinding tool according to the invention, in which the at least one the lateral surfaces 6 or 10 approximately parallel to the axis of rotation arranged or inclined up to and including 90 ° to the axis of rotation 1 and the carrier body is a device for connecting the Flap grinding tool with a quick clamping device for Connection of the flap grinding tool to a drive device having. The device for connecting the Flap grinding tool adapted with a quick release to part of e.g. in the case of the usual bayonets or To form a bayonet connection. Such a connection allows one particularly safe and quick connection of the tool to a The drive and the correct fit of the tool is visually good recognizable. Instead of the bayonet connection a one or Multi-start screw or nut threads, especially as steep threads be provided, the thread advantageously a rectangular or Is trapezoidal thread.

An embodiment is also not shown in the figures preferably for stationary operation, where the Flap grinding tool has a large length in the axial direction to form a large grinding width. It is useful if the carrier body has two or more disks 4a in order to ensure good Support of the support ring 4b on the drive shaft and thus one to ensure even removal.

Claims (11)

1. Flap-type grinding tool, which is configured symmetrically about an axis of rotation (1), having

   a) a plurality of abrasive flaps (2) disposed on the periphery and/or end faces,

   b) a support body (4a, 4b, 12, 13, 14), on which the abrasive flaps (2) are fixed, and

   c) a device (5, 11) for connecting the flap-type grinding tool to a drive apparatus,

   d) wherein the support body (4a, 4b, 12, 13, 14) having at least one rotationally symmetrical lateral surface (6, 10). on which the abrasive flaps (2) are at least partly fixed,
   characterized in that

   e) the support body (4a, 4b, 12, 13, 14) comprises at least one central element (7) configured as a disk (4a) which extends essentially radially to the axis of rotation (1) and the device for connecting the flap-type grinding tool to a drive apparatus has at least one contact surface (8) formed by the disk (4a) for connecting the flap-type grinding tool to a drive apparatus, and

   f) the support body (4a, 4b, 12, 13, 14) additionally comprises a carrier ring (4b) on whose radially outermost outside one of the lateral surfaces (6, 10) is formed approximately parallel to the axis of rotation (1) or at least inclined at less than 75° to the axis of rotation (1), and the carrier ring (4b) and the disk (4a) are produced from different materials.
2. Flap-type grinding tool according to claim 1,
   characterized in that
   the disk (4a) is sufficiently offset in the region of the contact surface (8) such that the contact surface (8) is disposed axially outside a body of rotation described by the outside edges of the abrasive flaps (2).
3. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   the disk (4a) is produced from a plastic, preferably a fiber-reinforced plastic, from aluminum or from steel.
4. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   the carrier ring (4b) is produced from a plastic, preferably a fiber-reinforced plastic, from a hard rubber, from a hard paper, from aluminum or from steel.
5. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   carrier ring (4b) and disk (4a) are connected to one another by press-fitting, bonding or welding.
6. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   the disk (4a) is formed by an automatically acting eccentric or centrifugal force clamping apparatus (13, 14, 15, 16).
7. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   the support body (4a, 4b, 12, 13, 14) has a plurality of disks (4a).
8. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   abrasive flaps (2) are disposed both on the periphery (9) and on one end face (10) of the flap-type grinding tool.
9. Flap-type grinding tool according to one of the preceding claims,
   characterized in that
   the support body (4a, 4b, 12, 13, 14) has a device for connecting the flap-type grinding tool to a rapid clamping apparatus for connecting the flap-type grinding tool to a drive apparatus.
10. Flap-type grinding tool according to claim 9,
    characterized in that
    the device for connecting the flap-type grinding tool to a rapid clamping apparatus is adapted to form part of a socket connection or bayonet connection.
11. Flap-type grinding tool according to claim 9,
    characterized in that
    the device for connecting the flap-type grinding tool to a rapid clamping apparatus comprising a single-pitch or multi-pitch screw or nut thread, the thread being a coarse-pitched thread, preferably a rectangular or trapezoidal thread.

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