EP2248627A2 - Tool for grinding or polishing for an oscillation drive - Google Patents

Abstract

The tool has an oscillation drive (10) with a drive motor for driving a drive spindle (14) around a longitudinal axis (22) in an oscillating manner. The drive spindle is connected with a tool unit (24) e.g. grinding disk, in a form-fit manner, where the tool unit has a working surface. A quotient of dimensions of the working surfaces of the tool unit and a nominal consumption power of the drive motor amounts to 40 millimeter square per watt. The tool unit has a support element made of elastomer material, where the support element has a metallic adhesive material.

Description

The invention relates to an oscillating tool with an oscillation drive with a drive motor, from which a work spindle can be driven in a rotationally oscillating manner about its longitudinal axis, wherein the work spindle can be connected to a tool which has a working surface for grinding or polishing.

Such Oszillationswerkzeug is from the WO 87/02924 A1 known.

The known oscillation tool has an oscillation drive, on whose work spindle a tool in the form of a grinding or polishing tool is rotatably received, possibly by means of a positive connection. The oscillation drive moves its work spindle at high frequency and low pivot angle around its Longitudinal axis, whereby a particularly good grinding result can be achieved, in particular when triangular grinding tools are used with rounded outer edges. This also allows grinding along longitudinal edges and in corners.

According to the aforementioned document, conventionally shaped grinding or polishing tools should also be able to be used on the oscillation drive.

On the basis of the document mentioned above, an increasing development of tools has emerged in recent years, which are driven by an oscillation drive in order to fulfill a wide variety of tasks. In addition to grinding and polishing of the most diverse surfaces, this also includes an application of the tool for sawing, cutting off joint material and the like.

In practice, however, has shown that the use of conventional grinding or polishing tools on such oscillating drives only to a small removal, especially during grinding, leads. Thus, numerous tools for grinding or polishing have been developed for such oscillating drives, which are adapted to the special requirements for use with oscillating drives. In general, such tools always have a relatively small working surface, since they are used for special work and it is expected that otherwise the grinding result is deteriorated or even an overload of such oscillating drives can occur.

In practice, therefore, predominantly eccentric grinders or orbital sander are still used for grinding larger surfaces.

The invention is therefore based on the object of specifying an oscillating tool with a tool for grinding or polishing, which leads to improved results when grinding or polishing. In particular, when sanding or polishing as improved as possible grinding or polishing and possibly a higher removal should be achieved.

This object is achieved in an oscillating tool according to the aforementioned type in that the quotient of working surface of the tool (given in square millimeters) and from the rated power consumption of the drive motor (given in watts) is at least 35 mm ² / W.

The object of the invention is completely solved in this way.

According to the invention, it has been recognized that these two quotients are important parameters for the performance of the oscillating tool, in particular during surface grinding. The higher the power of the drive motor, the greater the working surface can be formed. Correspondingly, the larger the weight of the oscillating tool (ie the machine without tools), the greater the working area.

In the prior art, depending on the driving power of the oscillation drive, the working surface has always been severely limited either by its rated power rating or by its weight, since too large a working surface has been considered disadvantageous. As a result of too large a work surface, either a worse grinding result was expected, or even an overload or damage to the transmission or the motor of the oscillation drive.

According to the present invention, this prejudice existing in the prior art deviates and a larger work surface is proposed.

The quotient of work surface and rated power consumption can preferably even be at least 40 mm ² / W.

According to a further embodiment of the invention, the quotient of working surface of the tool (given in square millimeters) and of the total weight of the oscillating tool (given in grams, without tools) is at least 5.5 mm ² / g _.

Finally, the quotient of work surface and weight may preferably be at least 6.0 mm ² / g or even at least 7.0 mm ² / g.

Overall, the invention proposes a larger working surface of the oscillating tool than in conventional oscillating tools, resulting in a particular suitability for surface grinding.

The enlarged working surface of the oscillating tool is preferably combined with various measures for reducing the inertia of the tool received on the drive spindle. Thus, a larger work surface can be used with the same drive power or constant weight.

The connection between the drive spindle and the tool is preferably positive fit to ensure a safe power transmission even at high loads.

The tool has according to a further embodiment of the invention, a support member for receiving a grinding or polishing agent, and a driver on which a positive connection element, preferably in the form of a mounting opening, is provided for positive connection with the work spindle of the oscillation drive, wherein the driver element with a back element is connected to which the carrier element is fixed, wherein the driver element is a greater strength than the back member, and wherein the back member is made of a lighter material than the driver element.

By using an additional back element on which on the one hand the support element is attached and which is on the other hand connected to the driver element, created a possibility to build the tool more flexible overall and in particular to design with a lower inertia compared to a conventional such tool.

By reducing the mass inertia, an improvement in the result when grinding or polishing can be achieved. If the mass inertia is significantly reduced compared to conventional tools, e.g. Other materials used, resulting in significantly improved results when grinding or polishing. In particular, a higher removal at reduced load of the machine can be achieved.

Since the driver element has a greater strength than the back element and the back element consists of a lighter material than the driver element, the tool can have a total sufficient strength to not withstand even at high loads in continuous operation on a positive entrainment to the work spindle of the oscillation. On the other hand, is provided by the back member, which consists of a much lighter material than the driver element, the necessary supporting function for the support member, which is usually made of a resilient material, such as. a polyurethane foam. Thus, overall, the necessary stability of the entire tool can be ensured, while the inertia of the entire tool can be significantly reduced compared to a conventional structure.

The driver element preferably has a significantly smaller area than the back element and only provides the necessary stability in the area of the positive locking Admission. In contrast, the back element preferably extends to the outer edge of the carrier element in order to ensure the necessary stability in the edge regions. Thus, a significantly reduced mass inertia of the tool is made possible by this combined structure, in particular a reduced moment of inertia is achieved with respect to the central axis of the positive recording, with which the tool can be attached to the work spindle of an oscillating drive.

It has been found that with such a construction of the tool, in particular during grinding, results can be obtained which correspond to the grinding action of eccentric grinders, e.g. are clearly superior in terms of the grinding pattern and removal. In this way, in particular, an application for surface processing, ie for surface grinding or for polishing larger areas is possible.

According to a further embodiment of the invention, the entrainment element consists of a material having a Vickers hardness of at least 250 HV, preferably of at least 320 HV, wherein the hardness is preferably at a maximum of 840 HV. The most preferred range is 420 ± 80 HV.

Similarly, the tensile strength of the material constituting the entrainment member may preferably be in the range of 1100 to 2650 N / mm ² , more preferably in the range of 1500 to 1700 N / mm ² .

These measures ensure that the driver element has sufficient strength in the region of its positive-locking element in order to avoid deflection even in continuous operation.

The driver element may for example consist of a steel, preferably of a hardened steel, which benefits a cost-effective structure.

It is understood, however, that other materials can be used which ensure the necessary stability against knocking in the region of the positive-locking element.

According to a further embodiment of the invention, the back element consists of an aluminum or magnesium alloy.

In particular, aluminum alloys are very inexpensive and lightweight and have the necessary stability for the support of the support element in the edge areas.

According to a further embodiment of the invention, the back element consists of a plastic or a composite material.

With such an embodiment, the back element can be made even easier than in a production of about aluminum or magnesium. Thus, the total inertia of the tool can be further reduced overall, whereby the effectiveness of the tool during grinding or polishing can be further increased. In addition, plastics or composite materials can be produced inexpensively in large quantities.

According to a further embodiment of the invention, the driver element is welded to the back element, soldered or glued.

While a very strong, permanent connection can be produced by welding or soldering, bonding allows particularly cost-effective production. Depending on the adhesive used in this case also a high strength of the connection can be achieved.

According to a further embodiment of the invention, the driver element has a plurality of recesses, through which the weight of the driver element is reduced.

In this way, the inertia of the driver element and thus also of the entire tool can be reduced even further, while still ensuring sufficient stability.

Likewise, the back element can also have a plurality of recesses, by means of which the weight of the back element and thus the mass inertia are reduced.

According to a further embodiment of the invention, the driver element is positively connected to the back element, preferably via projections of the back element, which engage in associated recesses of the driver element.

In this way, a high-strength connection between the driver element and the back element can be achieved, which is also able to cope with high loads during operation. In particular, if the back element is made of a plastic, results in a cost-effective production, since the corresponding elevations or projections of the back member can be injected with about the same during production by injection molding.

In an additional development of this embodiment, the projections of the back element are caulked or fused to the recesses of the driver element.

In this way, a high-strength and durable connection between the back element and driver element, wherein the additional use of an adhesive can be completely dispensed with.

The driver element and the back element are preferably plate-shaped, whereby a simple construction of the entire tool is ensured.

The support member preferably consists of an elastomeric tool, e.g. from a polyurethane foam.

It is understood, however, that depending on the application, suitable materials are provided for the carrier element, so that other materials can be used.

According to a further embodiment of the invention, the tool is plate-shaped and has in the region of its working side a diameter greater than 100 mm, preferably greater than 110 mm.

It has been found that in such an embodiment, the use of oscillating drives, as offered by the applicant under the name Multimaster® or Supercut, can achieve particularly good grinding results even in surface grinding. Thus, e.g. Conventional abrasives are used, which are offered for grinding plates of about 115 mm diameter from numerous manufacturers.

In a further embodiment of the invention, suction channels are provided, which extend from the working side through the carrier element, the back element and through the driver element.

Thus, the tool according to the invention can also be used for grinding with simultaneous suction directly at the workplace.

In the course of the separate embodiment of the carrier element and the back element, the design and, in the course of the suction channels, greater design freedom can be achieved ensure, as is the case with conventional tools, which have only one driver element, which also takes over the carrier function for the carrier element.

According to a further embodiment of the invention, the carrier element on the tool side, an adhesive element for releasably receiving a grinding or polishing agent. The adhesive element may preferably consist of a Velcro material, in particular of a metal Velcro material.

In this way, conventional grinding or polishing agents can be used, which are used in numerous embodiments for connection with a Velcro material. A slight change of the grinding or polishing agent is guaranteed.

It will be appreciated that the support member may have a circular working surface or may have a working surface other than a circular shape, e.g. a triangular or quadrangular work surface with convex rounded outer edges, a teardrop shape with a point on one side, or any other shape.

It is further understood that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination but also in other combinations or in isolation, without departing from the scope of the invention.

Figur 1

eine Teilansicht eines Oszillationsantriebes mit einem auf der Arbeits- spindel des Oszillationsantriebes befestigten Werkzeug;

Figur 2

einen vergrößerten Schnitt durch das Werkzeug gemäß Figur 1 im Bereich der Aufnahme an der Arbeitsspindel;

Figur 3

eine perspektivische Ansicht des Werkzeuges gemäß Figur 1 von der Arbeitsseite her;

Figur 4

eine perspektivische Ansicht des Werkzeuges gemäß Figur 1 von der Rückseite her;

Figur 5

eine Ansicht des Trägerelementes gemäß Figur 2 von der Rückseite her;

Figur 6

eine perspektivische Ansicht des Trägerelementes gemäß Figur 5;

Figur 7

eine Ansicht des Rückenelementes gemäß Figur 2;

Figur 8

eine Ansicht des Mitnehmerelementes gemäß Figur 2; und

Figur 9

einen Schnitt durch eine gegenüber der Ausführung gemäß Figur 2 abgewandelte Ausführungsform eines erfindungsgemäßen Werkzeuges.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. Show it:

FIG. 1

a partial view of an oscillating drive with a mounted on the working spindle of the oscillation drive tool;

FIG. 2

an enlarged section through the tool according to FIG. 1 in the area of the recording on the work spindle;

FIG. 3

a perspective view of the tool according to FIG. 1 from the work side;

FIG. 4

a perspective view of the tool according to FIG. 1 from the back;

FIG. 5

a view of the carrier element according to FIG. 2 from the back;

FIG. 6

a perspective view of the carrier element according to FIG. 5 ;

FIG. 7

a view of the back element according to FIG. 2 ;

FIG. 8

a view of the driver element according to FIG. 2 ; and

FIG. 9

a section through a respect to the execution according to FIG. 2 modified embodiment of a tool according to the invention.

In FIG. 1 an oscillation drive of known design in the region of its gear head 12 is shown and designated overall by the numeral 10. The oscillation drive 10 has a work spindle 14 which can be driven by an oscillation gear (not shown) about its longitudinal axis 22 in a rotationally oscillating manner. The drive is carried out at a high frequency of, for example, 5000 to 25000 oscillations per minute and low pivot angle between about 0.5 and 7 degrees. At the outer end of the work spindle 14, an inventive tool 24 is fixed for grinding or polishing.

Known, available on the market oscillating tools have relatively small work surfaces compared to the drive power (power consumption in watts) or the total weight (in grams, without tools) on.

For example, the quotient of working surface and drive power for oscillation tools available on the market is between 9.5 and 33.86 mm ² / W and the quotient of working surface and weight between 2.5 and 5.42 mm ² / g.

According to the invention, a larger work surface is now proposed in comparison to the power consumption or the weight.

If a sanding pad with a diameter of 115 millimeters is used as the tool, a quotient of 41.42 mm ² / W or a quotient of 8.66 mm ² / g results with an oscillation drive of the type Fein Multimaster FMM250 marketed by the applicant.

If a sanding pad with a diameter of 115 millimeters is used as the tool, a quotient of 41.42 mm ² / W or a quotient of 7.42 mm ² / g results with an oscillation drive of the Fein Multimaster FMM250Q sold by the applicant _.

This means a significantly enlarged work surface with otherwise the same drive.

The structure of the tool 24 will be described below with reference to FIGS. 2 to 8 explained in more detail.

In FIG. 2 is an enlarged sectional view through the tool 24 according to FIG. 1 shown, which is attached to the outer end of the work spindle 14.

The tool 24 is plate-shaped with a diameter of about 115 mm on the machining side.

The tool 24 has a driver element 26, which consists of steel, for example made of CK85 with a Vickers hardness of 420 HV 50/30. On the driver element 26, a central fastening opening is formed, which is designed as a positive-locking element 34 is, for example, hexagonal in accordance with FIGS. 3 and 4 , The hexagonal form-fitting element 34 of the driver element 26 is matched to a corresponding form-fitting element 19 at the outer end of a spindle tube 18 of the work spindle 14. This results in a positive connection between the driver element 26 and the work spindle fourteenth

At the driver element 26, a plate-shaped back member 28 is fixed by gluing. The back element 28 has a larger area than the driver element 26 and preferably extends over the entire diameter of the tool 24. It serves to receive and support a carrier element 30, which is glued over its entire surface with the back element 28. The back element 28 consists e.g. from an aluminum alloy.

The support member 30 is preferably made of a slightly compliant material, e.g. from a polyurethane. At the machining side of the tool 24, the support member 30 is closed by an adhesive member 32 which is preferably formed in the form of a Velcro material and on which a grinding or polishing element can be placed from the outside.

The carrier element 30 also has a central recess 21. The back element 28 has according to FIG. 7 a central opening 48 whose diameter is slightly smaller than the diameter of the recess 21 of the support member 30, but slightly larger than the outer dimensions of the positive locking element 34 of the driver element 26 (see. FIG. 8 ).

According to FIG. 2 Thus, a fastening means 16, such as in the form of a bolt 16, are inserted through the recess 21 of the support member 30 into the tool 24 and is located in the in FIG. 2 shown clamping position from the inside to the back member 28 and fixes the back member 28 together with the driver element 26 on the spindle tube 18. This results from the positive connection between the positive-locking element 34 in the form of hexagonal attachment opening on the driver element 26 and the correspondingly shaped positive-locking element 19 on the spindle tube 18 a positive connection. In this case, the back element 28 simultaneously serves as a stop 36.

In addition to the central recess 21, in the present case the carrier element is also penetrated by suction channels 38, which extend from the working side through the carrier element 30, through the back element 28 and through the driver element 26 and terminate in outlet openings 40 of the driver element 26. On this page, a suitable suction device may be provided in order to be able to vacuum dust accumulating during a grinding process directly at the work site.

The FIGS. 5 and 6 show the support member 30 from the back. It can be seen that a total of eight axially extending passage openings 42 are provided in the carrier element 30, which open out to the back element 28 via a distributor channel 44 which is closed towards the middle by an inner collar 46. On the back element 28, the total of three intermediate openings 50 are provided, which open into the distribution channel 44. In the driver element 26, which is glued to the back member 28, again congruent outlet openings 40 are provided, which are aligned with the intermediate openings 50 of the back member 28.

Overall, a very effective extraction from the working side by the support member 30, the back member 28 and the driver element 26 can be ensured.

The positive-locking element 34 in the form of the attachment opening is hexagonal in the illustrated case. However, it is understood that any shapes for the positive-locking element 34 are possible, provided that a corresponding adaptation to the associated positive-locking element 19 of the work spindle 14 is ensured. For example, instead of a hexagonal shape, a twelve-sided or a any other polygonal shape can be used. In particular, a star-shaped receptacle with convexly rounded balancing and concave protrusions therebetween approximately according to the U.S. Patent 6,945,862 conceivable. This patent is hereby incorporated by reference in its entirety.

The tool 24 described above is significantly lighter by the two-part structure with a driver element 26 and a back member 28 bonded thereto in comparison to a conventional tool in which the driver element would occupy the entire rear surface of the support member 30 and would also be made of steel for reasons of strength formed and has a lower mass moment of inertia with respect to the longitudinal axis 22nd

As a result of this construction, the tool according to the invention can advantageously be used in conjunction with an oscillation drive for surface grinding. This results in a very intense grinding action, which is clearly superior to the grinding result with eccentric grinders of comparable size.

In FIG. 9 a modification of the tool according to the invention is shown and indicated generally at 24a. In modification to the execution according to FIG. 2 the driver element 26 is penetrated by a plurality of recesses 62, engage in the associated projections 60 of the back element 28 in a form-fitting manner. On the back side facing away from the machining side, these projections are correspondingly widened from the outside, for example by the action of heat, so that extensions 64 result, by which the driver element 26 and the back element 28 are firmly connected to one another.

The back member 28 is in this embodiment preferably made of a plastic material which is produced by injection molding and is melted after the attachment of the driver element 26 by the action of heat. In this way can be dispensed with a bond.

On the back element 28, in turn, the carrier element 30 is received in the manner described above. On the working side of the support member 30, an adhesive element 32 is formed in the form of a Velcro strip surface. In the illustration according to FIG. 9 If necessary, a grinding or polishing element 58, which is easily exchangeable on the surface of the adhesive element 32 by the action of the hook-and-loop fastener elements, is attached.

It is understood that this design could additionally be provided with suction channels, as far as desired.

It is further understood that, although here the tool has been exemplified as a sanding pad, any shapes for the tool are conceivable. For example, these may be triangular tools, where appropriate with convexly rounded side edges, quadrangular tools possibly with convexly rounded side edges, tools with a tip on one side and a rounding on the other side (drop shape) and the like. In any case, the advantages of the invention are achieved independently of the shape of the working surface of the tool.

Claims (15)

Oscillating tool with an oscillating drive with a drive motor having a certain engine power (rated power) and of which a work spindle (14) about its longitudinal axis (22) is rotationally oscillating drivable, wherein the work spindle (14) with a tool (24, 24a) is connectable , comprising a working surface for grinding or polishing, characterized in that the quotient of working surface of the tool (given in square millimeters), and the rated power (in watts), at least 35 mm ² / W, preferably at least 40 mm ² / W is. Oscillating tool according to claim 1, which has a specific dead weight, wherein the work spindle (14) is positively connected to the tool (24, 24a), characterized in that the quotient of working surface and of its own weight, (given in grams, without tools) , at least 5.5 mm ² / g, preferably at least 6.0 mm ² / g, more preferably at least 7.0 mm ² / g. Oscillating tool according to one of the preceding claims, characterized in that the work spindle (14) for positive connection with the tool (24, 24a) is formed. Oscillating tool according to one of the preceding claims, with a with the drive spindle (14) connectable tool, characterized in that the tool is a carrier element (30) for receiving a grinding or polishing agent, a driver element (26) on which a positive locking element (34), preferably in the form of a fastening opening, for the positive connection with the work spindle (14) of the oscillation drive (10), that the driver element (26) connected to a back element (28) is, on which the carrier element (30) is fastened, that the driver element (26) has a greater strength than the back element (28), and that the back element (28) consists of a lighter material than the driver element (26). Oscillating tool according to claim 4, characterized in that the entrainment element (26) consists of a material having a Vickers hardness of at least 250 HV, preferably at least 320 HV, wherein the entrainment element (26) is preferably made of a steel, preferably of a hardened steel. Oscillating tool according to claim 4 or 5, characterized in that the back element (28) consists of an aluminum or magnesium alloy, and that the back element (28) is preferably made of a plastic or a composite material. Oscillating tool according to one of claims 4 to 6, characterized in that the driver element (26) with the back element (28) is welded, soldered or glued. Oscillating tool according to one of claims 4 to 7, characterized in that at least the driver element (26) or the back element (28) has a plurality of recesses (62) for weight reduction. Oscillating tool according to one of claims 4 to 8, characterized in that the driver element (26) with the back element (28) is positively connected, preferably via projections (60) of the back member (28) in associated recesses (62) of the driver element ( 26) engage, wherein the projections (60) of the back member (28) preferably are caulked or fused at the recesses (62) of the driver element (26). Oscillating tool according to one of claims 4 to 9, characterized in that at least the driver element (26) or the back element (28), preferably both elements (26, 28), are plate-shaped. Oscillating tool according to one of claims 4 to 10, characterized in that the carrier element (30) consists of an elastomeric material. Oscillating tool according to one of claims 4 to 11, characterized in that the tool (24, 24a) is plate-shaped and in the region of its working side (54) has a diameter greater than 100 mm, preferably greater than 110 mm. Oscillating tool according to one of claims 4 to 12, characterized by suction channels (38, 40, 42, 44) extending from the working side (54) through the carrier element (30), the back element (28) and through the driver element (26). extend. Oscillating tool according to one of claims 4 to 13, characterized in that the carrier element (30) on the tool side an adhesive element (32) for releasably receiving a grinding or polishing means (58). Oscillating tool according to one of claims 4 to 14, characterized in that the adhesive element (32) consists of Velcro material, preferably made of metal Velcro material.

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