Abstract:
The invention is based on a bearing arrangement for vibratingly supporting a grinding disk ( 24 ) on a grinding apparatus ( 10 ), in particular in a vibrating grinder, having a plurality of elastic vibration bodies ( 48 ), which can be connected on the one hand to the grinding disk ( 24 ) and on the other to the grinding apparatus ( 10 ). It is proposed that the vibration bodies ( 48 ) are disposed, individually or in groups of a plurality of vibration bodies ( 48 ) each, in a plurality of modules ( 42 ) that are separate from one another.

Description:
CROSS-REFERENCE 
   The invention described and claimed hereinbelow is also described in PCT/DE 03/02337, filed Jul. 11, 2003 and DE 102 51 556.5, filed Nov. 6, 2002. This German Patent Application, whose subject matter is incorporated here by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119 (a)–(d). 
   BACKGROUND OF THE INVENTION 
   The invention is based on a bearing arrangement for vibratingly supporting a grinding disk on a grinding apparatus, in particular a ¼-blade vibrating grinder. 
   In conventional vibrating grinders, the grinding disk is driven to execute lateral vibrating motions by an eccentric; the grinding disk is connected to the grinding apparatus by elastic vibration legs. 
   The vibration legs prevent the rotary motion of the eccentric from being transmitted to the grinding disk, on the one hand, and thus form a means of securing the grinding disk against relative rotation. 
   On the other hand, the vibration legs absorb the contact pressure acting on the grinding disk and carry it onward to the grinding apparatus. 
   Finally, upon their torsion-caused deformation, the vibration legs are intended to dissipate as little vibrational energy, in the form of energy of deformation, as possible so as to economize on electrical energy for driving purposes; this is especially important for grinding apparatuses operated by rechargeable batteries, because of the limited capacity of such batteries. 
   Conventionally, the vibration legs are joined together by a plastic bridge and form a unitary component, so that all the vibration legs are mounted together with the plastic bridge. 
   In grinding apparatuses with integrated removal of dust by vacuum, however, the installation space for the vibration legs is very limited, so that such plastic bridges with a plurality of vibration legs cannot be installed. 
   SUMMARY OF THE INVENTION 
   By comparison, the invention provides a bearing arrangement for vibratingly supporting a grinding disk on a grinding apparatus in which the vibration legs are each disposed individually or in groups of a plurality of vibration legs in a plurality of separate modules. 
   Dividing up the individual vibration legs among a plurality of modules offers the advantage that for mounting in a grinding apparatus, less mounting space is needed, since the modules can each be installed individually. 
   Preferably, each module has three vibration legs, but the individual vibration legs may also be divided up among the individual modules in some other way. For instance, each module may have one, two, or four vibration legs. 
   In the bearing arrangement of the invention, the elastic connection of the grinding disk to the grinding apparatus need not necessarily be done by means of vibration legs, however, whose length is substantially greater than their thickness. Instead, it is also possible to use vibration bodies of some other design, as long as the vibration bodies form an elastic connection between the grinding disk and the grinding apparatus. 
   Moreover, the bearing arrangement of the invention can be used not only in a grinding apparatus but also in a polishing apparatus, in which a polishing disk is driven to execute lateral vibrational motions by an eccentric. The bearing arrangement of the invention then connects the polishing disk to the polishing apparatus in a manner capable of vibration. 
   In a preferred embodiment of the invention, the individual modules have a bayonet mount for mounting them on the grinding apparatus. Securing the individual modules is thus preferably done by slipping the individual modules on and then displacing them or twisting them, so that mounting can be done without a tool. 
   Preferably, the individual modules each have one groove and/or one tongue, so that adjacent modules, in the mounted state, form a tongue-and-groove connection. This offers the advantage that the strength of the bearing arrangement of the invention, despite being divided up among a plurality of modules, is similar in quality to conventional bearing arrangements with a plastic bridge for connecting the individual vibration legs. 
   The individual modules preferably have a mounting body for fastening to the grinding apparatus and a guide body for guiding the grinding disk; the mounting body is joined to the guide body by at least one of the vibration bodies. The guide body with the grinding disk can thus execute vibrational motions relative to the mounting body, motions that are generated for instance by an eccentric. 
   Preferably, for being screwed to the grinding disk, the guide body has a screw receptacle, which may for instance comprise a simple blind bore that can be engaged on the inside by a fastening screw. Thus the fastening of the grinding disk is done by means of screws, which are screwed into the screw receptacle through the grinding disk from the workpiece side of the grinding disk. 
   To make mounting the grinding disk on a grinding apparatus with the bearing arrangement of the invention easier, the guide body, on its side toward the grinding disk, preferably has a protrusion which positively engages a suitably adapted fastening receptacle in the grinding disk. 
   Preferably, the protrusion on the guide body is non-round, in order to form a means of securing against relative rotation. When the grinding disk is screwed tightly to the bearing arrangement of the invention, the torque introduced into the guide body of the bearing arrangement by the fastening screw is then diverted into the grinding disk, via the positive-engagement connection, fixed against relative rotation, between the protrusion on the guide body and the fastening receptacle of the grinding disk. 
   In a preferred embodiment, the mounting body of the bearing arrangement of the invention is platelike and on one side edge has at least one recess for a suitably adapted tongue on the grinding apparatus. Upon installation, the individual modules are accordingly slipped onto the grinding apparatus in such a way that the tongue on the grinding apparatus engages the associated recess on the side edge of the module. Next, the modules are displaced, so that the tongue on the grinding apparatus is no longer located above the recess, but instead grasps the side edge of the mounting body and fixes it as a result. For disassembly, the module must then be displaced again such that the tongue is located above the recess in the side edge of the mounting body, whereupon the module can be simply taken off. 
   Moreover, in one embodiment of the invention, the mounting body has at least one protrusion, which in the mounted state forms a connection by frictional engagement with a suitably adapted receptacle on the grinding apparatus. Preferably, this protrusion is immediately adjacent the recess in the side edge of the mounting body, so that upon displacement of the mounting body, a frictional or clamping action is created, whereby the module is fixed. 
   Furthermore, the mounting body, on the side toward the grinding apparatus and/or on the side remote from the grinding apparatus, has a tongue, which in the mounted state forms a tongue-and-groove connection with a suitably adapted groove on the grinding apparatus. 
   It should also be noted that the invention is not limited to the bearing arrangement described above but instead also encompasses a complete grinding or polishing apparatus with such a bearing arrangement. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages will become apparent from the following description of the drawings. In the drawings, one exemplary embodiment of the invention is shown. The drawing, description and claims include numerous characteristics in combination. One skilled in the art will expediently consider the characteristics individually as well and put them together to make useful further combinations. 
     Shown are: 
       FIG. 1 , a sectional view through a conventional vibrating grinder; 
       FIGS. 2   a – 2   c , perspective views of a module of a bearing arrangement of the invention; and 
       FIGS. 3   a – 3   b , the module, shown in  FIGS. 2   a  through  2   c , in various positions during the installation. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The cross-sectional view in  FIG. 1  shows a vibrating grinder  10 , which is of conventional construction and will be described briefly below, in order then to address the special features of the invention. 
   The vibrating grinder  10  has an electric motor, which drives a power takeoff shaft  14 ; the power takeoff shaft  14  is additionally rotatably supported in a ball bearing  16 . 
   The power takeoff shaft  14  has a free end onto which an eccentric sleeve  18  is press-fitted, so that the eccentric sleeve  18  is secured on the power takeoff shaft  14  in a manner fixed against relative rotation and fixed in the axial direction. Instead of the press fit employed here, however, the fastening of the eccentric sleeve  18  to the power takeoff shaft  14  may be done in some other way, such as by means of a screw connection. 
   The eccentric sleeve  18  accordingly rotates with the power takeoff shaft  14  and is therefore balanced relative to the power takeoff shaft  14 , to avoid vibration in operation. 
   On its end toward the workpiece, the eccentric sleeve  18  furthermore has a cup-shaped, cylindrical receptacle for a ball bearing  20  with an inner ring and an outer ring; the receptacle for the ball bearing  20  is disposed eccentrically relative to the power takeoff shaft  14 . The outer ring of the ball bearing  20  is pressed into the receptacle, while a sleevelike receptacle part  22  is press-fitted into the inner ring of the ball bearing  20 . 
   The sleevelike receptacle part  22  serves to secure a grinding disk  24 , and for that purpose, on its end toward the tool, it has a female thread  26 , as can be seen particularly in  FIG. 2 . For securing the grinding disk  24  to the grinding apparatus  10 , the grinding disk has a mounting bore  28  in its middle region, through which bore a central fastening screw  30  can be screwed into the female thread  26  of the receptacle part  22 . Securing the grinding disk  24  to the grinding apparatus  10  by a screw connection thus makes simple replacement of the grinding disk  24  possible, so that once suitable grinding disks  24  have been selected, either plane grinding or contour grinding can be selectively done with the same grinding apparatus  10 . 
   Moreover, the grinding apparatus  10  has a plurality of elastic vibration legs  32  of polyoxymethylene (POM), which guide a guide element  34  in a manner that is secure against relative rotation but is laterally resilient. However, the vibration legs  32  may comprise other elastic, tough materials, which as much as possible exhibit no material fatigue whatever even after long periods of operation and frequent deformations; examples that can be named are polyamide (PA) and polypropylene (PP). 
   The guide element  34  engages the inside of an encompassing collar  36 , formed integrally onto the top of the grinding disk  24 , so that the freedom of motion of the grinding disk  24  is limited to plane-parallel motions. The encompassing collar  36  of the grinding disk  24  is accordingly non-round and is approximately triangular, as a result of which the grinding disk  24  is secured against twisting. 
   Accordingly, because of the eccentric bearing of the receptacle part  22  in the eccentric sleeve  18 , a rotation of the power takeoff shaft  14  leads to plane-parallel grinding motions of the grinding disk  24 . 
   The grinding apparatus  10  furthermore has a housing  38 , which on its underside is flush with the top of the grinding disk  24  by means of a sealing lip  40 . 
     FIGS. 2   a  through  2   c  and  3   a  and  3   b , conversely, show a module of a four-part bearing arrangement that can be employed in a vibrating grinder similar to the vibrating grinder  10 , instead of the guide element  34  with the vibration legs  32 . 
   The module  42  has a mounting plate  44  and a guide plate  46 , which are joined together by three elastic vibration legs  48 ; the mounting plate  44 , guide plate  46 , and vibration legs  48  are of plastic. Because of their elasticity, the three vibration legs  48  enable a lateral vibrational motion of the grinding disk  24  that is driven by the eccentric sleeve  18 . 
   In the installed state, the guide plate  46  is joined to the grinding disk  24 . To that end, the guide plate  46  has a screw receptacle  50 , which is engaged in the installed state by a fastening screw, which by means of a screw connection connects the grinding disk  24  to the guide plate  46 . The guide plate  46  furthermore, on its side toward the grinding disk  24 , has a protrusion  52 , which in the installed state engages a receptacle in the grinding disk  24  in order to establish a positive-engagement connection between the grinding disk  24  and the guide plate  46 . The protrusion  52  here is non-round and has two flattened sides, thus forming a means of securing against relative rotation. This is advantageous, since in this way, when the fastening screw is tightened in the screw receptacle  50 , the torque introduced into the guide plate  46  is diverted into the grinding disk  24  via the positive-engagement connection, secure against relative rotation, between the protrusion  52  and the associated receptacle in the grinding disk  24 . 
   In the installed state, conversely, the mounting plate  44  of the module  42  is connected to the housing  38  of the grinding apparatus  10 , as can be seen from  FIGS. 3   a  and  3   b . The connection between the mounting plate  44  and the housing  38  of the grinding apparatus  10  is effected by means of a bayonet mount, so that simple installation and disassembly of the module  42  without a tool is possible. 
   To this end, the mounting plate  44  has two recesses  54 . 1 ,  54 . 2  on one side edge, and these are engaged, in the mounting position shown in  FIG. 3   a , by two tongues  56 . 1 ,  56 . 2 , so that the module  42  can be introduced into the housing  38  on the side toward the workpiece. In the process, the tongues  56 . 1 ,  56 . 2  slide through the associated recesses  54 . 1 ,  54 . 2  on the mounting plate  44 . 
   Next, the module  42  is then thrust out of the mounting position shown in  FIG. 3   a  into the final position shown in  FIG. 3   b ; in the final position of the module  42 , the tongues  56 . 1 ,  56 . 2  rest on the mounting plate  44  next to the recesses  54 . 1 ,  54 . 2  and thereby clamp the mounting plate  44  firmly. 
   To improve the clamping action between the tongues  56 . 1 ,  56 . 2  and the mounting plate  44 , a protrusion  58 , which in the final position of the module  42  presses against the tongue  54 . 1 , is integrally formed onto the side of the mounting plate  44  toward the tongue  56 . 1 , at the edge of the recess  54 . 1 . 
   Moreover, two tongues  60 ,  62  are integrally formed onto the mounting plate  44  and guide the mounting plate  44  in the installed state; the tongue  60  engages a suitably adapted groove in the housing  38  of the grinding apparatus  10 . 
   The mounting plate  44  of the module  42  also has a wedge-shaped groove  64 , which is engaged in the mounted state by a suitably adapted tongue of an adjacent module, so that the individual modules of the bearing arrangement of the invention are connected mechanically to one another and can nevertheless be installed individually and therefore in a way that requires little space. 
   Overall, the bearing arrangement of the invention comprises four modules  42  that are mirror images of one another, and which each have either the groove  64  or a suitably adapted tongue. 
   The invention is not limited to the preferred exemplary embodiment described above. On the contrary, many variations and modifications may be made that also make use of the concept of the invention and are therefore within its patent scope. 
   
     
       
             
           
             
             
             
           
         
             
                 
             
             
               List of Reference Numerals 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
                 
               10 
               Grinding apparatus 
             
             
                 
               14 
               Power takeoff shaft 
             
             
                 
               16 
               Ball bearing 
             
             
                 
               18 
               Eccentric element 
             
             
                 
               20 
               Ball bearing 
             
             
                 
               22 
               Receptacle part 
             
             
                 
               24 
               Grinding disk 
             
             
                 
               26 
               Female thread 
             
             
                 
               28 
               Mounting bore 
             
             
                 
               30 
               Fastening screw 
             
             
                 
               32 
               Vibration leg 
             
             
                 
               34 
               Guide element 
             
             
                 
               36 
               Collar 
             
             
                 
               38 
               Housing 
             
             
                 
               40 
               Sealing lip 
             
             
                 
               42 
               Module of the bearing arrangement 
             
             
                 
               44 
               Mounting plate 
             
             
                 
               46 
               Guide plate 
             
             
                 
               48 
               Vibration leg 
             
             
                 
               50 
               Screw receptacle 
             
             
                 
               52 
               Protrusion 
             
             
                 
               54.1, 54.2 
               Recess 
             
             
                 
               56.1, 56.2 
               Tongue 
             
             
                 
               58 
               Protrusion 
             
             
                 
               60 
               Tongue 
             
             
                 
               62 
               Tongue 
             
             
                 
               64 
               Groove