Fastening system, fastening adapter and fastening method

Abstract

The invention relates to a fastening system for mounting a roller-shaped tool on a drive shaft of a drive motor with the help of a fastening adapter comprising a hollow-cylindrical basic body which comprises in the interior a fastening apparatus for mounting on a drive shaft. A plurality of lamellae originate from the hollow-cylindrical basic body which are distributed about the cylinder axis and are spaced from one another by slits and which are each tilted in their direction perpendicular to the cylinder axis by a predetermined angle relative to the radial direction. The outside diameter of the fastening adapter can be reduced elastically by exerting pressure or the action of a shearing force in the direction of the tilting on the lamellae. The roller-shaped tool comprises a rigid cylindrical pass-through opening for this purpose whose inside diameter is smaller than the outside diameter of the fastening adapter in the relaxed state. The invention further relates to a fastening adapter for use in a fastening system and a method for fastening a roller-shaped tool with a tubular pass-through opening on a fastening adapter for a drive shaft of a drive motor, with the fastening adapter being embraced with a twist and thus being compressed and being slid in this state into the pass-through opening of the tool, that the compression is then removed, whereupon the fastening adapter expands again in the pass-through opening and thus forms a torsionally rigid connection with the tool by clamping and frictional engagement with the tool on its outer jacket surface.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application No. DE 102006017516.6, filed Apr. 13, 2006, the disclosure of which is hereby incorporated by reference in its entirety.

FIELD OF THE TECHNOLOGY

The invention relates to a fastening system for mounting roller-shaped tools on a drive shaft of a drive motor with the help of a fastening adapter, a fastening adapter and a method for mounting roller-shaped tools on a fastening adapter. Such roller-shaped tools are for example surface machining tools such as grinding or polishing rolls. Such tools are usually driven by means of a drive motor such as a face grinding machine or longitudinal grinding machine by means of a rotating drive shaft. The term tool roller shall also be used below alternatively for a roller-shaped tool. For the purpose of a torsionally rigid connection between a drive shaft and a tool roller, the latter often comprises a pass-through opening with a special fastening apparatus which is adjusted to a specific drive shaft. Drive shafts of different machines frequently differ in their diameter however. There are also different systems for the fastening. They can be based for example on screwed or plug-in connections. When a certain type of tool roller is to be used in a versatile manner with different drive machines it was necessary until now that the rollers needed to be manufactured in different configurations of pass-through openings and fastening apparatus.

BACKGROUND OF THE INVENTION

This specialization in different drive shafts is cumbersome and causes high costs. That is why one has begun to produce uniform tool rollers and to provide the same with a special insert for the different drive shafts. It would be desirable however when such an insert could be reused as an adapter. Precisely one adapter would then be sufficient for each drive shaft, to which different tool rollers could be attached.

SUMMARY OF THE INVENTION

In view of this background it is the object of the present invention to provide a system for fastening a roller-shaped tool on a drive shaft of a drive motor with a fastening adapter, a fastening adapter and a method for mounting roller-shaped tools on a fastening adapter, with the fastening adapter offering a stable hold for the tool, enabling easy mounting and being reusable.

This object of the invention is achieved by an apparatus according to the independent claim 1. A fastening system in accordance with the invention comprises a fastening adapter, with the help of which a roller-shaped tool can be mounted on a drive shaft of a drive motor. A fastening adapter in accordance with the invention comprises a hollow-cylindrical basic body which comprises in the interior a fastening apparatus for mounting on a drive shaft and from which a plurality of lamellae originate which are distributed outwardly about the cylinder axis and are spaced from one another by slits. The lamellae are each tilted in their direction perpendicular to the cylinder axis by a predetermined angle relative to the radial direction. The outside diameter of the fastening adapter can be reduced elastically by exerting pressure or the action of a shearing force in the direction of the tilting on the lamellae. The compression of the fastening adapter occurs substantially in such a way that the cavities between the lamellae, more precisely the slits, are reduced. Depending on the material of the lamellae, a compression of the lamellae themselves can be involved. As a result of the action of shearing forces at the ends of the lamellae, which means forces which act tangentially on the surface in the direction of the tilting, a “smoothing” of the lamellae is effected. Since the lamellae are tilted relative to the radial direction in the relaxed basic state, the direction in which the lamellae rest on each other is already predetermined and the exertion of pressure on the ends of the lamellae is sufficient in order to press the lamellae against each other. To enable such elastic deformation of the fastening adapter, the lamellae can consist entirely of elastic material. An elastic joint could also be sufficient which enables a further tilting of a stiff lamella. The compression of the fastening adapter concerns an elastic deformation. When there are no longer any pressure or shearing forces, the lamellae will spread out again and will assume their original form and orientation again. The fastening adapter will then have its original diameter again.

Grinding or polishing devices in which the fastening adapter in accordance with the invention is used with roller-shaped tools are often hand-held appliances which are guided by a worker by hand. Such appliances usually have a preferred running direction for reasons of work safety. This means for the tool rollers and the fastening adapters in accordance with the invention that they are also used with a preferred direction of rotation. The lamellae are tilted in the direction of movement which is preferred in operation of the tool in the case of a fastening adapter in accordance with the invention. This leads to the advantage that the holder of the tool on the fastening adapter is additionally stabilized in operation during a grinding or polishing process, as will be explained below in closer detail. During a grinding or polishing process, the rotational movement of the tool is slightly braked by friction on the tool. This braking causes a braking of the ends of the lamellae as a result of friction between tool roller and fastening adapter. If the lamellae were tilted against the running direction, then this would correspond to a shearing force in the direction of the tilting on the rotating ends of the lamellae, leading to a smoothing of the lamellae and thus a compression of the fastening adapter. The fixing of the roller-shaped tool would thus be loosened at this moment. If the lamellae are tilted in the running direction of the roller-shaped tool, the shearing force relative to the lamellae acts in the opposite direction. This promotes a stronger spreading of the lamellae. In the case of lamellae tilted in the running direction the lamellae will stand up more strongly, as a result of which the clamping seat and friction between the fastening adapter and the roller-shaped tool will be enhanced even further.

The stable fixing of the tool roller on the fastening adapter prevents slippage of the tool roller on the fastening adapter. Moreover, vibrations of the tool can thus be prevented, which under certain circumstances could leave chatter marks on the grinding surfaces.

A roller-shaped tool in accordance with the invention comprises a rigid cylindrical pass-through opening for the fastening adapter whose inside diameter is smaller than that of the relaxed fastening adapter. The difference in the diameter can be in the magnitude of less than 1 mm, whereas the diameter itself preferably lies in the range of a few centimeters, e.g. between 3 and 7 cm. The inside diameter of the pass-through opening of the tool roller preferably corresponds to 44.75 mm, whereas the outside diameter of the relaxed fastening adapter is preferably 45 mm. The length of the fastening adapter is preferably between 80 mm and 100 mm, more preferably 90 mm. This length corresponds appropriately also to the length of the tool roller.

The elastic deformability of the fastening adapter allows a simple mounting of the tool roller on the same. For this purpose, the fastening adapter is compressed at first and then placed in the pass-through opening of the tool roller in order to expand there again until it sits tightly in a clamping seat.

Suitable roller-shaped tools are for example mop wheels, mat wheels or other grinding or polishing tools for surface machining. They generally have a basic cylindrical shape. This is not necessary from a principal standpoint however. Barrel-shaped rollers or such profiled in a different way are also possible. The roller-shaped tools of the fastening adapter in accordance with the invention have a cylindrical pass-through opening. Said pass-through opening is rigid, so that its circular cross section is maintained essentially even under load.

In a preferred further development of the invention, the pass-through opening of the tool roller is formed by a stiff pipe with a circular cross section. Said pipe then carries the actual tool material. The pipe can consist for example of plastic such as PVC or ABS, a composite material such as Pertinax or epoxy synthetic resin, or of metal such as aluminum or steel. Said pipe forms the rigid pass-through opening of the tool roller, whereas the actual tool material is arranged outside about the pipe and is carried by the same. Depending on the type of tool, said tool material can be a grinding material in the form of pressed grinding particles, grinding lamellae, a layer of polishing mat or the like.

For mounting a tool roller in accordance with the invention on a fastening adapter in accordance with the invention, the fastening adapter is compressed, as explained above, by means of pressure or the action of a shearing force on the lamellae and inserted into the pass-through opening of the tool roller. The shearing force on the ends of the lamellae can be exerted for example by embracing the fastening adapter with a twist. The embracing can occur by hand in this case. A mechanical solution is also possible. Once the fastening adapter is situated in the pass-through opening of the roller-shaped tool, the embracement is released, whereupon the lamellae of the fastening adapter will spread out again and press against the inside wall of the pass-through opening of the roller-shaped tool. As a result of the slight undersize of the pass-through opening with respect to the diameter of the fastening adapter, a certain residual compression of the fastening adapter is maintained. The thus remaining elastic tension in the fastening adapter increases the pressure of the ends of the lamellae against the inside wall of the pass-through opening. The thus increased friction between the ends of the lamellae and the pass-through opening ensures a torsionally rigid seat of the tool roller on the fastening adapter.

The fastening adapter is equipped on its part with a pass-through opening and a fastening apparatus for the drive shaft for driving the fastening adapter by the drive shaft. The diameter of the pass-through opening and the special fastening apparatus are adjusted to the drive shaft to be used. Possible variants of the fastening apparatus are in this case an inside thread or a double groove in which a respective drive shaft can engage. All known variants of torsionally rigid shaft-hub connections are principally suitable. According to a preferred further development of the invention the fastening apparatus is an inside thread however. Suitable standard threads are for example M10 threads, M14 threads or ⅝″ threads.

The tool roller rotates in operation with the fastening adapter, driven by the drive shaft. An outwardly directed centrifugal force acts in addition on the tilted and tensioned lamellae by the rotation. It amplifies the pressure of the lamellae on the inside wall of the pass-through opening. This increases the friction between the ends of the lamellae and the pass-through opening. The fixing of the tool on the fastening adapter is stabilized in this process.

In a preferred further development, the lamellae of the fastening adapter in accordance with the invention consist of an elastic material. Such a material is rubber or polyurethane with a preferred hardness of between 60 Shore and 100 Shore. This hardness range is especially advantageous for avoiding disturbing vibrations. When the entire lamellae are made of an elastic material, the compression properties of the fastening adapter are thus improved. On the other hand, the expansion caused by centrifugal force is facilitated during operation. Elastic lamellae mean for compression that the compression occurs not only as a result of the reduced cavities between the lamellae but also as a result of a compression of the lamellae themselves. Moreover, the construction is simplified as compared with a variant with only elastic joints.

The lamellae are preferably also arranged in such a way that they have the lowest cross section at their contact point on the hollow-cylindrical basic body. In the case of lamellae made of a uniform elastic material this leads to the consequence that the lamellae will preferably bend off at such contact points for compression on the one hand and also for expansion on the other hand. An elastic joint thus formed in a way. The lamellae are also preferably arranged in such a way that in the relaxed state of the fastening adapter the outer ends of all lamellae jointly form a cylindrical jacket surface which is interrupted by slits. Relaxed state shall mean here that the fastening adapter is idle and no pressure or force acts upon the same. This preferred arrangement of the ends of the lamellae ensures that the ends of the lamellae sit close in an especially favorable manner in the pass-through opening of the roller-shaped tool. The contact surface between the ends of the lamellae and the tool roller is then especially large. Friction is thus improved between fastening adapter and tool roller. The preferred shape of the lamellae with the smallest cross section at the contact point and the outer end which jointly form a cylinder jacket surface can be realized in such a way that the lamellae are subdivided by slits with respective parallel boundary walls. This form is obtained in such a way that even slits of constant width are cut into a hollow-cylindrical basic body. Reference in more detail will be made thereto in the description of the figures.

In a preferred further development of the fastening adapter in accordance with the invention, its circumferential edge is chamfered on at least one of its face sides. This facilitates the insertion of the fastening adapters into the pass-through opening of the roller-shaped tool.

In an advantageous further development of the invention, the fastening adapter is cylindrically extended about the center with the fastening apparatus on its face side facing the drive motor in operation. A cylindrical excess portion is thus formed from which no lamellae protrude. A tool roller in accordance with the invention is slid during mounting only to such an extent over the fastening adapter that the cylindrical excess portion will just protrude. The cylindrical excess portion is then used as a spacer between the drive motor and the tool roller. The fastening apparatus in the pass-through opening of the fastening adapter appropriately continues into said extensions. The entire fastening adapter can be arranged in such a way that the fastening apparatus and the pass-through opening are situated in a cylindrical metal core around which the lamellae made of an elastic material are arranged. In this case, the excess portion can simply be formed by a metal core extended relative to the lamellae.

For the purpose of additional stabilization of such a fastening adapter on the drive shaft of a drive motor, a thread for a setscrew with a setscrew can be provided in the cylindrical excess portion in a further development of the invention. This setscrew allows additionally fixing a screwed joint and the degree of fastening. The setscrew is then appropriately attached on the side in the cylindrical excess portion.

In a preferred embodiment of the fastening adapter in accordance with the invention, the same comprises a stop ring for the tool roller at its end facing the drive motor. Said stop ring can consist of the material of the lamellae or of another material such a metal. It can be produced integrally both with the lamellae as well as the metal core of the fastening adapter, or it can be attached retroactively. When the fastening adapter is arranged with a cylindrical excess portion, the stop ring is appropriately arranged between the excess portion and the lamellae at the end of the lamellae. The outside diameter of the stop ring is larger than the inside diameter of the pass-through opening in the tool roller and smaller than or equal to its outside diameter. Even when the stop ring can be formed from an elastic material, it is not compressible to the extent that the tool roller can be slid over the same. The stop ring thus offers a top for the tool roller and is used as a spacer to the drive motor.

The object of the invention is further achieved by a fastening adapter for use in a fastening system as described above.

The object of the invention is also achieved by a method according to the independent method claim. A method in accordance with the invention for fastening a roller-shaped tool with a tubular pass-through opening on a fastening adapter for a drive shaft of a drive motor comprises the embracement of the fastening adapter with a twist, as a result of which the fastening adapter is compressed. The fastening adapter is thereupon slid in this compressed state into the pass-through opening of the tool, whereupon the compression is stopped, whereupon the fastening adapter expands again in the pass-through opening and thus forms a torsionally rigid connection with the tool by clamping and frictional engagement on its outer jacket surface. Twist shall be understood here as a twisting of the outer circumference of the fastening adapter relative to its center marked by the pass-through opening in the direction of movement preferred in operation. In the case of a fastening adapter in accordance with the invention with lamellae, this cases the lamellae to be pressed flatly in the direction of the preferred direction of movement. The method in accordance with the invention is therefore especially suitable for a fastening adapter in accordance with the invention according to the apparatus claims. Fastening adapters of a different structure are principally also possible.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in closer detail below by reference to embodiments shown in the drawings, wherein:

FIG. 1 shows a fastening adapter in a perspective view;

FIG. 2 shows a fastening adapter in a top view of a face side;

FIG. 3 shows one step of the method with a fastening adapter in accordance with the invention;

FIG. 4 shows a fastening adapter in a roller-shaped tool in a top view of a face side, and

FIG. 5 shows a tool roller and a fastening adapter in sectional view through the longitudinal axis.

DETAILED DESCRIPTION OF THE INVENTION

According to the FIGS. 1 to 5, a fastening adapter 10 comprises a hollow-cylindrical basic body 11 from which lamellae 15 protrude. The lamellae 15 and the hollow-cylindrical basic body 11 can be made integrally or be assembled. The lamellae 15 are separated from each other by slits 14. Both the slits 14 as well as the lamellae 15 are tilted relative to the radial direction by a predetermined angle α (FIG. 2).

The cross-sectional shape of the lamellae 15 is predetermined by the cross-sectional shape of the interposed slits 14. The slits 14 are arranged as channels with an approximately trapezoid cross section, with the two boundary surfaces being parallel to the adjacent lamellae 15. By predetermining the shape of the intermediate spaces 14 between the individual lamellae 15, the shape of the lamellae 15 is also predetermined. The intermediate spaces are arranged as slits 14 of constant width. Accordingly, the cross section of the lamellae 15 is similar to that of a circle sector which increases in width with increasing radius. The lamellae 15 are therefore cylinder sectors which are arranged in a tilted way from the radial direction. The widening cross section of the lamellae 15 which finishes outwardly with the circular arc sector is especially advantageous because the contact surface between lamellae 15 and the pass-through opening of the tool 17 is maximized. Friction between the fastening adapter 10 and the tool roller is also maximized in this way. Based on the shape of the lamellae 15 and its outwardly widening cross section, the tilting angle α can be defined differently. It assumes different values depending on the definition and the reference point. The values can vary in the range of approximately 15° to 90° depending on the manner of definition. All lamellae 15 are tilted objectively under the same angle relative to their respective radial direction.

The fastening adapter 10 also has a preferred operating direction which is indicated in FIG. 2 by arrow 20. The lamellae 15 are tilted from their radial direction in the preferred operating direction 20. In operation, the braking of the ends of the lamellae by friction between the tool roller and the fastening cylinder causes a shearing force directed in the opposite direction. As a result, the lamellae 15 will spread out even further, so that the connection between the fastening adapter and the roller-shaped tool is stabilized even further.

The fastening adapter is equipped with a fastening apparatus 12 for the drive with a drive shaft of a machine. The embodiment shown in the FIGS. 2, 4 and 5 comprises an inside thread with which it can be screwed onto a respective drive shaft. The embodiment shown in FIG. 3 differs from that shown in FIG. 2 only in such a way that the fastening apparatus is arranged as a double groove instead of an inside thread. In addition, other cross sections are possible for respective drive shafts.

The fastening adapter can be compressed by pressure on the outer ends of the lamellae or by action of a shearing force in the direction of the tilting of the lamellae 15. FIG. 3 shows how this compression can occur by embracing the fastening by hand. In a fastening adapter in accordance with the invention, the compression can be achieved on the one hand by pressure on the lamellae 15 or by embracement with a twist. The embracement with a twist means that the center of the fastening adapter is held tight with the fastening apparatus 12, whereas the outer ends of the lamellae are twisted relative to the same. The direction of twisting is indicated by the arrow in the hand in FIG. 3. In this compressed state, the fastening adapter 10 has a reduced diameter and can thus be slid into the pass-through opening 21 of a roller-shaped tool 17. By releasing the adapter 10, the lamellae 15 will spread out again in the pass-through opening 21 of the tool 17 until they push against the inside wall of the pass-through opening 21 and press against the same.

FIG. 4 shows a fastening adapter 10 which is slid into the tool roller 17 and is spread out there. Since the inside diameter of the pass-through opening 21 is slightly lower than the outside diameter of the fastening adapter 10, the lamellae 15 are slightly pressed against each other and are tensioned. The pass-through opening 21 of tool 17 is formed here by a PVC tube 18 which carries a ring cylinder 19 of grinding material on its outside. The pressure of the lamellae 15 on the PVC tube 18 increases the friction between the lamellae 15 and the PVC tube 18. The pressure and thus the friction by a centrifugal force acting upon the lamellae 15 is increased additionally in operation. The fixing of the tool on the fastening adapter 10 is thus especially stable in operation.

FIG. 5 shows a further embodiment of a fastening adapter in a tool roller in a sectional view through the longitudinal axis. An inside thread is provided as a fastening apparatus 12, which inside thread is situated in a metal core of the fastening adapter 10. The metal core is extended beyond the length of the lamellae 15 and forms a cylindrical excess portion 23. A thread for a setscrew 24 is additionally provided in the cylindrical excess portion. The screwed joint of the fastening adapter on a drive shaft can thus be fixed in addition. The cylindrical excess portion 23 is situated on the end of the fastening adapter 10 facing the drive motor. The fastening adapter 10 further comprises a stop ring 22 which is also made of metal like the core and is connected with the same. A roller tool 17 made of a PVC pipe and a slip-ring cylinder 19 is slid from the other end of the fastening adapter 10 over the same. In order to facilitate this step, the fastening adapter 10 is chamfered at said end 25. The stop ring 22 has an outside diameter which is larger than the inside diameter of the PVC pipe 18 and smaller than the outside diameter of the slip-ring cylinder 19. During the mounting of the tool roller 17 on the fastening adapter 10 it therefore prevents that the tool roller is slid too far over the fastening adapter 10. This ensures a sufficient distance between the drive motor and the tool roller.

Claims

1. A fastening system for mounting a roller-shaped tool with a pass-through opening on a drive shaft of a drive motor, comprising:

a fastening adapter having a hollow-cylindrical basic body for mounting on the drive shaft and a plurality of lamellae spaced from each other by slits and distributed about the cylinder axis protruding outwardly from the body, with the lamellae each being tilted in a direction perpendicular to the cylinder axis at a predetermined angle α relative to the radial direction and the outside diameter of the fastening adapter, wherein in a relaxed state the fastening adapter is larger than the inside diameter of a pass-through opening of the roller-shaped tool, and can be reduced elastically by exerting pressure and/or through the action of a shearing force in the direction of tilting on the lamellae, and wherein the pass-through opening of the roller-shaped tool is arranged in a rigid and cylindrical fashion and the lamellae of the fastening adapter are tilted in the direction of movement of operation of the tool.

2. A fastening system according to claim 1, wherein the pass-through opening of the roller-shaped tool is formed by a stiff pipe.

3. A fastening system according to claim 1, wherein the fastening apparatus is internally threaded.

4. A fastening system according to claim 1, wherein the lamellae of the fastening adapter consist of an elastic material with a hardness between 60 Shore and 100 Shore.

5. A fastening system according to claim 1, wherein the lamellae of the fastening adapter have the smallest cross section at their contact point with the hollow-cylindrical basic body.

6. A fastening system according to claim 1, wherein in the relaxed state of the fastening adapter the outer ends of all lamellae form a cylinder jacket surface interrupted by slits.

7. A fastening system according to claim 1, wherein the circumferential edge of the fastening adapter is chamfered on at least one of its face sides.

8. A fastening system according to claim 1, wherein the fastening adapter is extended in the center about the fastening apparatus on its face side which faces the drive motor in operation, as a result of which a cylindrical excess portion is formed which has a smaller diameter than the other part of the fastening adapter.

9. A fastening system according to claim 1, wherein a thread for a setscrew as well as a setscrew are provided in the cylindrical excess portion, which setscrew is used in addition to the fastening apparatus for fixing the fastening adapter to the drive shaft.

10. A fastening system according to claim 1, wherein the fastening adapter comprises a stop ring on the face side which faces the drive motor in operation, with the diameter of said ring being so large that it will not fit into the pass-through opening of the roller-shaped tool.

11. A fastening adapter for use in a fastening system according to claim 1, which comprises a hollow-cylindrical basic body which has in the interior a fastening apparatus for mounting on the drive shaft and from which a plurality of lamellae protrude which are spaced from each other by slits and are outwardly distributed about the cylinder axis, with the lamellae each being tilted in their direction perpendicular to the cylinder axis about a predetermined angle α relative to the radial direction and the outside diameter of the fastening adapter being reducible elastically by exerting pressure and/or through the action of a shearing force in the direction of tilting on the lamellae, wherein the lamellae of the fastening adapter are tilted in the direction of movement which is preferred in operation.

12. A method for fastening a roller-shaped tool with a rigid cylindrical pass-through opening on a fastening adapter for mounting on a drive shaft of a drive motor, comprising:

embracing the fastening adapter being with a twist and thus compressing it and in this state and sliding it into the pass-through opening of the tool and lifting the compression so that the fastening adapter expands again in the pass-through opening and thus forms a torsionally rigid connection with the tool by clamping and frictional engagement on its outer jacket surface, with the twist corresponding to a twisting of the outside circumference of the fastening adapter relative to its center in the direction of movement of operation of the tool.