Abstract:
Disclosed is a tool for sawing, grinding, cutting or rasping, for a hand-held power tool appliance driven in an oscillating manner, in particular for an electric power tool driven in an oscillating manner, wherein the tool comprises at least one predetermined break line, which allows a part of the tool to be broken off.

Description:
CROSSREFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority from German patent application Serial No. 10 2011 016 662.9, filed on Apr. 5, 2011, the entire contents of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a tool for a hand-held power tool appliance, in particular for sawing, grinding, cutting, scraping or rasping, in particular for an electric power tool oscillatingly driven. 
         [0003]    A great variety of tool types that can be used in combination with oscillatory drives are known from the prior art. Such tools are used, in particular, for sawing, grinding, cutting, scraping or rasping. Known from EP 0 881 023 A2, for example, is a series of cutting or grinding tools that can be used in combination with an oscillatory drive, in particular to enable cuts to be made under conditions of restricted space, for example to enable rectangular recesses to be made, e.g. on frames, in particular by plunge cuts. A rectilinear cutting edge, for example, can be provided for this purpose, the cutting edge having a toothing that is adjoined on both sides, at an angle of less than 90°, by non-toothed lateral edges. The two lateral edges can also be disposed parallel to one another. 
         [0004]    Various further variants of tools that can be used in combination with oscillatory drives are known. 
         [0005]    The shape of these tools is in each case is directed to a particular application. Thus, for example, there are broad saw blades for longer cuts, and narrow saw blades for smaller cuts or small recesses. Or there are long tools and short tools for sawing workpieces of greater or lesser thickness. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of this, the invention is a first object of the invention to disclose a tool for a hand-held power tool appliance, that allows to achieve a wide range of applications with only one tool. 
         [0007]    It is a second object of the invention to disclose a tool, that is particularly suited to be oscillatingly driven, in particular for sawing, grinding, cutting, scraping or rasping, and that can be used to achieve a wide range of applications with only one tool. 
         [0008]    It is a third object of the invention to disclose a tool that can still be used if it has become blunt. 
         [0009]    It is a forth object of the invention to disclose a tool that can be adapted to different geometries in a very simple way. 
         [0010]    According to one aspect, these and other objects are achieved by a tool for a hand-held power tool appliance that is oscillatingly driven, wherein the tool comprises: 
         [0011]    at least one fastening region configured for fastening to a hand-held power tool appliance, and 
         [0012]    at least one working region supported by the fastening region, 
         [0013]    wherein the working region comprises at least one predetermined break location, configured for allowing breaking off part of the working region along the predetermined break location. 
         [0014]    The object of the invention is thereby fully achieved. 
         [0015]    This is because, according to the invention, the tool itself can be altered by breaking off a part along the predetermined break location or break line. The tool can thus be used in at least two different embodiments, namely, in the delivery state, in which the predetermined break location is still intact, and in an altered state, in which at least a part of the tool has been broken off along the predetermined break location. The tool is thereby altered such that the result during working is an altered mode of operation. If a plurality of predetermined break locations are provided, this makes it possible to provide a range of differing embodiments of a tool. 
         [0016]    According to a further design of the invention, the tool has a working region, on which the at least one predetermined break location is realized. 
         [0017]    In this case, the at least one predetermined break location can be used to alter the working region by breaking off a part of the tool. 
         [0018]    The alteration in this case can be a reduction in the size of the working region by breaking off a part of the tool. 
         [0019]    Furthermore, the tool can have a cutting edge that can be altered by breaking off the at least one part. 
         [0020]    For example, the cutting edge can be shortened by breaking off the at least one part. 
         [0021]    Differing widths of application, or differing cut widths, can be realized in this manner. 
         [0022]    According to a further design of the invention, at least one predetermined break location extends along a cutting edge, in order to expose a new cutting edge when a part is broken off. 
         [0023]    In this way, the tool can continue to be used, even if the cutting edge or a part of the cutting edge is already worn. 
         [0024]    Furthermore, it is conceivable for the predetermined break location to extend along a cutting edge having a toothing that differs from that of a first cutting edge. 
         [0025]    This makes it possible to use the tool with differing toothings, it being possible, by breaking off a part, to change from a cutting edge having a first toothing to a cutting edge having a second toothing. For example, it is possible to change from a cutting edge having a Japan toothing, which provides for a considerably more aggressive cut, to a standard toothing that is suitable for wood or metal. 
         [0026]    According to a further design of the invention, at least one cutting edge is realized as a straight cutting edge. 
         [0027]    Alternatively, at least one cutting edge can also be realized as a curved cutting edge. 
         [0028]    According to a further design of the invention, a fastening region is provided, which has a fastening aperture for preferably positive connection to a power tool appliance driven in an oscillating manner. 
         [0029]    This provides for a secure and permanent connection to the power tool appliance driven in an oscillating manner, for a variety of applications. 
         [0030]    Furthermore, the tool can have a circular or arcuate working region, the at least one predetermined break location preferably defining a portion of a circle or a segment of a circle. 
         [0031]    Thus, for instance, a round saw blade can be used in such a way that, in its delivery state, it can be used for sawing less closely to edge regions. If a part is then broken off along a predetermined break location, one or more straight edges can thus be produced, thereby making it possible to work more closely to edge regions. Or it is possible to expose another cutting edge, which is located on a lesser diameter and thus has a greater curvature. 
         [0032]    The predetermined break location is preferably constituted by a material weakening or by at least one through-hole with at least one web remaining. 
         [0033]    The predetermined break location in this case can be formed, for instance, by a laser treatment, an erosive treatment, a stamping process or a grinding treatment. 
         [0034]    This enables the predetermined break location to be produced in a simple manner. Clearly, in this case, this predetermined break location is to be made such that there is no risk of the tool breaking off at the predetermined break location during normal use. If there are through-holes, the remaining webs must provide adequate robustness. 
         [0035]    It is understood that the above-mentioned features of the invention and those yet to be explained in the following can be applied, not only in the respectively specified combination, but also in other combinations or on its own, without departing from the scope of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]    Further features and advantages of the invention are disclosed by the following description, preferred exemplary embodiments being disclosed with reference to the drawing, wherein: 
           [0037]      FIG. 1  shows a top view of a first embodiment of a tool according to the invention; 
           [0038]      FIG. 2  shows a top view of a second embodiment of a tool according to the invention, in a representation enlarged in comparison with the representation according to  FIG. 1 , and 
           [0039]      FIG. 3  shows a top view of a third embodiment of a tool according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0040]    In  FIG. 1 , a first embodiment of a tool according to the invention is represented in a top view and denoted as a whole by the reference numeral  10 . The tool  10  is configured as a sawing tool, which is used in combination with an electric power tool oscillatingly driven by means of an oscillatory drive. 
         [0041]    Such oscillatory drives are known, for example, from the aforementioned EP 0 881 023 A1. The output shaft of the oscillatory drive in this case is made to oscillate about its longitudinal axis, this being at an oscillation frequency that is, for instance, between 5,000 and 25,000 oscillations per minute, and at a pivoting angle that is, for instance, between 0.5° and 5°. In order to ensure that the tool  10  is securely fastened to the output shaft of the associated oscillatory drive, the tool  10  is provided with a fastening region  12 , on which a fastening aperture  14  is provided. The shape of the fastening aperture  14  matches an associated shape of the output shaft of the oscillatory drive, in order thereby to ensure a positive connection. The fastening apertures  14  can be of any shape, for instance having a plurality of outward-facing recesses or rounded tips, adjacent recesses or rounded tips being connected to one another via curved portions that extend towards the central axis, as known, for instance, from EP 1 213 107 A1, which hereby is fully included by reference. 
         [0042]    Alternatively, any other shape can be provided, for example a polygon, a star shape, etc. Finally, it is also possible for the fastening aperture to be designed merely in the form of a circle, provided that no positive connection to the output shaft of the oscillatory drive is desired. 
         [0043]    The tool  10  additionally has a working region  16 , which can be configured integrally with the fastening region  12  or, as indicated in the present case in  FIG. 1 , connected to the same via a sequence of spot welds  18 . If a two-part embodiment is selected, different materials and production methods can be used for the fastening region  12 , on the one hand, and for the working region  16 , on the other hand, which may allow more cost-effective production or greater efficiency. In addition, an offset (not represented) can be provided between the fastening region  12  and the working region  16 . 
         [0044]    In its outer shape, the tool  10  represented in  FIG. 1  corresponds to the shape known from  FIG. 2  of EP 0 881 023 A2. The tool  10  thus has a working region  16  having a straight cutting edge  20 , which comprises a toothing. Adjoining the straight cutting edge  20  at both ends are non-toothed lateral edges, each of which, with the cutting edge  20 , encloses an angle that is less than 90°, for example approximately 70° to 85°. These two angles are equal, such that the tool  10  as a whole is symmetrical in its structure. 
         [0045]    According to the invention, a plurality of predetermined break locations are provided on both sides of a central, rectangular region  34  on the working region. For example, on one side, a predetermined break location extending out from the cutting edge  20 , parallel to the outer edge, is denoted by  22 , which predetermined break location terminates in a point  25  and from which a further predetermined break location  23  extends as far as the lateral edge. The predetermined break location  22  and the associated predetermined break location  23  can be used to break off the part  32  of the tool  10  delimited thereby, for example with the aid of combination pliers. This then results in a tool  10  that has been reduced in size and on which the cutting edge  20  has been shortened by a corresponding amount. When used as a saw, this means correspondingly shorter saw cuts, for instance when a plunge cut is made in solid material. 
         [0046]    In addition, further, subsequent predetermined break locations on the same side and/or on the opposite side can be used to reduce the size of the working region  16  of the tool  10  accordingly, as can be seen from  FIG. 1 . 
         [0047]    In this way, it is possible to effect differing cut widths on the cutting edge  20  on the working region  16 . A minimum cut width remains when all regions bordered by predetermined break locations have been parted off on both sides of the central region  34 . There then remains a central, rectangular region  34  having, on both sides, straight lateral edges that are parallel to one another. 
         [0048]    Besides reducing the working region  16 , the parting-off of parts  32  can also be used to renew the cutting edge, or a part thereof, when the cutting edge has become blunt. 
         [0049]    Particularly in the case of the embodiment according to  FIG. 1 , it must be taken into account that the peripheral regions of the cutting edge  20  become abraded more rapidly than the central part of the cutting edge. Thus, the cutting edge  20  can be reduced in size by parting off outer regions that have become blunt, such that work can then be better performed with the still remaining part of the working region  16 . 
         [0050]    In addition or as an alternative to this, a cutting edge  24 , or a plurality of cutting edges  24 ,  28 , can be provided, which is/are preferably parallel to the first cutting edge  20  and which is/are likewise realized with a toothing. A predetermined break location  24 ,  28  provided along the cutting edge  26  and  30 , respectively, thus enables an outer part of the cutting edge  20  to be broken off along the respectively new cutting edge  26  and  30 , respectively. A new cutting edge  26  or  30  is thus produced. 
         [0051]    The new cutting edges  26  and  30  can be realized so as to be identical to the first cutting edge  20 , having an identical toothing, or they can have a toothing that differs from the latter, as shown in  FIG. 1 . 
         [0052]    During use, the entire predetermined break location  24  can be parted off in its entirety along the cutting edge  26 , such that a continuous cutting edge  26 , extending in relation to the first cutting edge  20 , is obtained. In the present case, the second cutting edge  26  has a toothing that differs from the first cutting edge  20 , e.g. a Japan toothing. However, it can also be realized so as to have an identical toothing. 
         [0053]    Extending parallel thereto there is a further predetermined break location  28 , which defines a second cutting edge  30 , again having a corresponding toothing. 
         [0054]    Instead of parting off the entire predetermined break location  24  over its entire length, it is also possible to part off individual parts or a plurality of parts thereof. 
         [0055]    A modification of the embodiment previously described with reference to  FIG. 1  is represented in  FIG. 2 , and denoted as a whole by the reference numeral  10   a . The tool  10   a  again has a fastening region  12   a , which comprises a fastening aperture  14   a  and which is adjoined by a working region  16   a . In the case of the embodiment according to  FIG. 2 , the fastening region  12   a  and the working region  16   a  are designed so as to constitute a single piece and to lie in one plane. In the initial form, according to  FIG. 2  a tool  10   a  is obtained that has a rectangular working region  16   a , on which there is realized a straight cutting edge  20   a  provided with a toothing. Extending out from the cutting edge  20   a  there are non-toothed lateral edges, which are parallel to one another and which graduate into the fastening region  12   a.    
         [0056]    Extending parallel to the cutting edge  20   a , at a short distance therefrom, there are three further cutting edges  26   a ,  30   a ,  36   a , realized on which there are predetermined break locations  24   a ,  28   a ,  38   a.    
         [0057]    As described previously with reference to  FIG. 1 , after the cutting edge  20   a  has become worn, for instance, the second cutting edge  24   a , parallel to the latter, can thus be exposed in that the predetermined break location  24   a  is broken off over its full length, such that the cutting edge  26   a , which extends parallel to the cutting edge  20   a , is exposed in its entirety. The cutting edge  26   a  can be realized so as to differ from the cutting edge  20   a , as represented in  FIG. 2 , but it can also be of the same shape and size. 
         [0058]    Provided in the center of the working region  16   a  is a central region  34   a , which, starting from the cutting edge  20   a , has two lateral edges that are parallel to one another, and which widen outwards on both sides via curved lines and finally graduate into the outer edges on the fastening region  12   a . This central region  34   a  is delimited on both sides by a correspondingly shaped predetermined break location  23   a . Thus, starting from the fastening region  12   a  having parallel outer edges and progressing along the predetermined break location  23   a  on both sides, a tapered central region  34   a  is obtained, again having parallel outer edges, which is connected on both sides to the outer edge of the fastening region  12   a  via the curved predetermined break location  23   a . A total of three predetermined break locations, which are parallel to the outer edges and terminate at the cutting edge  20   a , are provided on each side of the central region  34   a . For these, one predetermined break location  22   a  is denoted on the right outer side. At a point  25   a , this predetermined break location graduates into the curved predetermined break location  23   a . An outer part  32   a  can thus be parted off by breaking off along the predetermined break location  22   a  and the predetermined break location  23   a , starting from the point  25   a . As a result, the working region  16   a  is made correspondingly narrower on this side, such that the new outer edge extends along the predetermined break location  22   a  and  23   a . The other predetermined break locations that are parallel thereto can be broken off in a corresponding manner on one side or on both sides, such that a correspondingly narrower working region  16   a  is obtained. 
         [0059]    As already explained above, as an alternative or in addition to this, one of the predetermined break locations  28   a ,  38   a  or  36   a  can be used to expose all or part of one of the cutting edges  26   a ,  30   a  or  36   a.    
         [0060]    A further exemplary embodiment of the invention is represented in  FIG. 3  and denoted as a whole by the reference numeral  10   b . The tool  10   b  is basically circular in form and has a central fastening region  12   b , again having a fastening aperture  14   b , according to the shape explained previously with reference to  FIG. 1 . 
         [0061]    The fastening region  12   b  is adjoined by an outer working region  16   b . Realized on the periphery there is a circular cutting edge  20   b , which has a toothing, and which extends, for instance, over 230° and which is delimited by a predetermined break location  22   b  that extends in the form of a chord and thus defines a segment of a circle. The periphery between the two points at which the predetermined break location  22   b  intersects the cutting edge  20   b  is closed by an arcuate cutting edge  26   b , on which a toothing is realized. The cutting edge  26   b , however, has a greater radius than the cutting edge  20   b.    
         [0062]    In the initial state, therefore, work can be performed with the tool  10   b  by using the cutting edge  26   b  if relatively long, but not very deep cuts are to be produced. If deeper cuts are to be produced, on the other hand, the remaining region of the cutting edge  20   b  is used. Breaking off the region  32   b  between the predetermined break location  22   b  and the cutting edge  26   b  produces a portion of a circle having a straight break edge. Further predetermined break locations that extend in a straight manner are denoted by  23   b  and  24   b . The predetermined break location  23   b  starts from one end of the predetermined break location  22   b  and extends towards the cutting edge  20   b . This predetermined break location  23   b  is of approximately the same length as the predetermined break location  22   b , or is somewhat shorter. A further predetermined break location  24   b  starts from a region of the cutting edge  20   b , between the point at which the predetermined break location  23   b  intersects the cutting edge  20   b  and the point at which the predetermined break location  23   b  meets the predetermined break location  22   b  at the cutting edge  20   b , and ends on the predetermined break location  22   b . If all predetermined break locations  22   b ,  23   b ,  24   b  are broken off, a tool  10   b  remains, which has an arcuate cutting edge  20   b  and which is delimited by a plurality of straight break-off edges along the lines  22   b ,  23   b ,  24   b.    
         [0063]    Also shown in  FIG. 3  are regions in the form of a sector of a circle, which, starting from the cutting edge  20   b , extend as far as an arc, concentric with the latter, at the transition to the fastening region  12   b , and which are delimited by predetermined break locations  40   b  extending in the radial direction. These predetermined break locations each graduate, via points  41   b , into a predetermined break location  42   b  extending in the form of a sector of a circle. 
         [0064]    In addition, in this region, there is a cutting edge  30   b  that extends concentrically in relation to the outer cutting edge  20   b . The latter can again be broken off, by breaking off the outer part along a predetermined break location extending along the cutting edge  30   b , such that the cutting edge  30   b  in this region is reduced in size concentrically in relation to the outer cutting edge  20   b  and extends concentrically in relation to the outer cutting edge  20   b.    
         [0065]    It is understood that any embodiments of predetermined break locations, differing from the exemplary embodiments represented, are possible in order to create working regions of reduced size, either having cutting edges that are shortened in comparison with the original cutting edge, or, alternatively, having cutting edges that are altered in comparison with the original cutting edge, and that might extend parallel to or deviate from the original cutting edge.