Patent Abstract:
A grinding tool for a grinding device with an oscillatory drive, in particular a rotary oscillatory drive is disclosed, the drive shaft of which can be driven about its longitudinal axis, wherein the grinding tool includes a holder having a support for securing to the drive shaft of the oscillatory drive, and whereon a form profile with a grinding mechanism is provided, wherein the holder includes a profile support for releasable securement of the form profile, and wherein the profile support includes a clamping region, into which the form profile can be inserted with a holding section and can be fixed thereto, and which can be elastically enlarged for releasing the form profile.

Full Description:
CROSSREFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims priority from German patent application 10 2015 112 510.2, filed on Jul. 30, 2015. The entire content of this priority application is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a grinding tool for a grinding device comprising an oscillatory drive, in particular a rotary oscillatory drive the drive shaft of which can be driven oscillatingly about its longitudinal axis, wherein the grinding tool comprises a holder comprising a support for securing to the drive shaft of the oscillatory drive, and whereon a form profile including a grinding means is received. 
         [0003]    Such a grinding tool is known from WO 2004/076125 A1. 
         [0004]    Such a grinding tool allows a grinding along longitudinal edges, in particular of profiles etc., even in view of the fact that for driving an oscillatory drive is used the rotary shaft of which is driven oscillatingly. By using an elastic grinding pad it is ensured that strong vibrations of the grinding tool are avoided despite of the grinding surface being straight at least in one direction. A grinding means configured as a grinding paper can be secured to the grinding pad by means of a suitable clamping device. 
         [0005]    Detrimental is the relatively inconvenient clamping of the grinding paper onto the grinding pad. In addition the grinding tool consists of several individual part which must be put together. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of this it is a first object to disclose an improved grinding tool for a grinding device with a oscillatory drive. 
         [0007]    It is a second object of the invention to disclose a grinding tool for a grinding device with a oscillatory drive that can be attached in a very simple way. 
         [0008]    It is a third object of the invention to disclose a grinding tool for a grinding device with a oscillatory drive including a holder whereon a grinding paper can be attached in a very simple way. 
         [0009]    It is a forth object of the invention to disclose a grinding tool for a grinding device with a oscillatory drive including a holder that allows for an easy handling. 
         [0010]    It is a fifth object of the invention to disclose an improved grinding tool that can be produced in a simple and cost-effective manufacture. 
         [0011]    According to a first aspect of the invention these and other objects are solved by a grinding tool for a grinding device comprising an oscillatory drive, the drive shaft of which can be oscillatingly driven about its longitudinal axis, said grinding tool comprising: 
         [0012]    a holder including a support for securing to said drive spindle of said oscillatory drive; 
         [0013]    a form profile including a grinding agent being received on said holder; 
         [0014]    a profile support provided on said holder for releasably securing said form profile, said profile support comprising a clamping region being configured for receiving and securing a holding section provided on said form profile when inserting said holding section into said clamping region, said clamping region being further configured for being elastically enlarged to allow a release of said form profile secured within said clamping region. 
         [0015]    According to the invention the grinding tool consists only of the holder and the form profile which can be secured to each other. In addition a grinding paper can be secured to the form profile. Alternatively the form profile may be equipped with an abrasive surface. 
         [0016]    All in all in this way a particularly simplified design results, a cost-effective manufacture and an exchange possibility for the form profile, in case the letter is worn down or a different form profile is desired. In addition by means of the simplified design and the abandonment of the spring elements consisting of a spring steel a considerable mass reduction results when compared to the prior art. In this way an improved grinding performance can be reached due to the smaller moment of inertia. 
         [0017]    According to another aspect of the invention at the clamping region there is attached at least one handle part for elastically enlarging the clamping region. 
         [0018]    In this way the clamping region can be simply elastically enlarged by applying pressure onto the at least one handle part to thus allow to release the form profile and the grinding paper from the clamping region in a particularly simple way or to insert into the latter. 
         [0019]    According to a further configuration of the invention the clamping region comprises an elastically enlargeable cavity into which the form profile can be inserted with its holding section and can be secured under the action of the internal stress of the clamping region. 
         [0020]    In this way the internal stress of the clamping region is used to allow a safe securement of the form profile with its holding section at the clamping region of the holder. 
         [0021]    Herein the form profile can be held frictionally engaged with its holding section within the cavity of the holder. 
         [0022]    In this way only the internal stress of the holder within its clamping region is used to ensure a frictionally engaged securement of the form profile at the holder. 
         [0023]    Alternatively or in addition the form profile may be held positively secured with its holding section within the cavity of the holder, preferably may be click-secured, wherein the positive locking or the click-securement can be released by elastically enlarging the cavity. 
         [0024]    In this way a particularly secure fixation of the form profile at the holder is ensured. 
         [0025]    According to a further development of the invention the clamping region at both axial ends of the cavity is limited by end sections wherein between the two end sections on both sides side sections extend which are spaced from the end sections. 
         [0026]    In this way the side sections can be configured spring-elastically to thereby allow a high internal stress whereby a safe securement of the form profile with its holding section within the profile support is made possible. 
         [0027]    According to a further development of the invention the cavity comprises a substantially U-shaped cross-section. 
         [0028]    With such a design the internal stress of the clamping region for securing the form profile can be ensured in a particularly simple way. 
         [0029]    According to a further design of the invention at a first one of the two side sections at least one gripping part is attached. 
         [0030]    Preferably herein at the first side section two gripping parts are attached which extend from the side sections slanted to the outside. 
         [0031]    By using one or several gripping parts at the first side section an elastic deformation of the clamping region can be ensured simply by exerting pressure, to allow for an exchanging the form profile. 
         [0032]    Herein the first side section starting from the bent section may yield into a plane section whereon the at least one gripping part is attached from the outside. 
         [0033]    The plane section herein preferably serves for direct positioning against the form profile. By contrast the bent section facilitates an elastic deformation upon application of a respective tensile or pressure force. 
         [0034]    The end sections that limit the cavity at both axial ends according to a preferred development of the invention each comprise an end face, and thereby interrelated side extensions substantially formed perpendicularly thereto which are each spaced from the adjacent first and second side sections by a slot. 
         [0035]    Such a design allows to receive and to guide an inserted form profile at the end sections, while by the spacing of the first and second side sections by means of a slot the elasticity of which can be ensured to allow for an elastic enlargement of the surrounded cavity for exchanging the form profile. 
         [0036]    According to a further preferred development of the invention at the end sections stops are provided for limiting the insertion depth of the form profile into the cavity. 
         [0037]    In this way a precise positioning of the form profile is ensured. 
         [0038]    According to a further development of the invention the form profile is coated with a grinding agent at least at a part of its outer surface. 
         [0039]    In this way a grinding is made possible directly using the outer surface of the form profile. 
         [0040]    According to a further development of the invention the form profile is configured for receiving a grinding paper which can be secured together with the form profile within the cavity of the holder. 
         [0041]    In this way after a wear-down of the form profile not the complete form profile must be disposed of. By contrast during grinding the grinding paper is worn which can be easily exchanged. 
         [0042]    Herein the grinding paper preferably has dimensions adapted to the outer surface of the form profile so that the grinding paper at least partially wraps around the outer surface of the form profile and is held with both ends between the holding section of the form profile and the side sections of the holder. 
         [0043]    In this way a simple securement of the grinding paper is made possible. 
         [0044]    According to a further development of the invention the grinding paper in the clamped state is pressed at each of its ends facing the holder into a depression which is formed in the assigned side sections of the holder. 
         [0045]    In this way an improved holding force for the grinding paper can be reached. 
         [0046]    According to a further development of the invention the form profile consists of an elastically yielding material, such as polyurethane foam for example. 
         [0047]    Such a material design facilitates a grinding along longitudinal edges and longitudinal profiles, since vibrations can be partially offset in this way. 
         [0048]    According to a further development of the invention the holder is made unitary from a plastic material, preferably as an injection molded part. 
         [0049]    This allows for a simple and cost effective manufacture and a particularly favorable design of the clamping region which is elastically enlargeable for releasing the form profile. 
         [0050]    According to a further development of the invention at both side sections of the holder on the surface facing the form profile webs are provided to which grooves at the form profile are assigned. 
         [0051]    Thereby a positive securement of the form profile is ensured so that during a grinding process a lateral yielding is avoided. 
         [0052]    The support of the holder preferably is configured for positive connection with the drive spindle of the oscillatory drive. 
         [0053]    To this end suitable embosses of the support or assigned adapters can be provided to ensure a direct mating to an assigned positive fitting support at the drive spindle. 
         [0054]    According to a further development of the invention the support of the holder defines a longitudinal axis, wherein the form profile extends at least in one direction of extension straight and perpendicularly to the longitudinal axis of the support. 
         [0055]    By such a design a grinding longitudinal profile is made possible. 
         [0056]    It is understood that the afore mentioned features and the features of the invention to be explained hereinafter can it only be used in the given combination, but also in different combinations or independently, without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0057]    Further features and advantages of the invention can be taken from the subsequent description of preferred embodiments with reference to the drawings. In the drawings show: 
           [0058]      FIG. 1  a perspective view of a grinding tool according to the invention; 
           [0059]      FIG. 2  the grinding tool according to  FIG. 1  which is secured to an assigned drive spindle of an oscillatory drive in its application position; 
           [0060]      FIGS. 3 a -3 c    an explosive representation of the individual parts of the grinding tool comprising a holder according to  FIG. 3 a   , a form profile according to  FIG. 3 b    and an assigned grinding paper according to  FIG. 3   c;    
           [0061]      FIG. 4  a top view of the holder according to  FIG. 3   a;    
           [0062]      FIG. 5  a cross section through the holder according to  FIG. 4  along the line V-V; 
           [0063]      FIG. 6  a plan view of the holder according to  FIG. 4  seen from the bottom; 
           [0064]      FIG. 7  a longitudinal section through the grinding tool according to  FIG. 1 ; and 
           [0065]      FIG. 8  a perspective cross section of the grinding tool according to  FIG. 7 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0066]    A grinding tool according to the invention is shown in  FIG. 1  in perspective and designated in total with numeral  10 . The grinding tool  10  comprises a holder  14  at which a form profile  16  and a grinding means  18  configured as a grinding paper are supported. 
         [0067]    The grinding tool  10  is configured for utilization with a oscillatory drive of known design, such as shown schematically in  FIG. 2 . The oscillatory drive  20  comprises a drive spindle  22  which can be driven about its longitudinal axis  24  in rotary oscillating fashion at high frequency in the range of about 10.000 to 25.000 oscillations per minute and with a small pivot angle of about ±0.5 to ±5°. The grinding tool  10  is secured positively at the outer end of the drive spindle  22  with a suitable support and is safeguarded by means of a securing element  26 . 
         [0068]    The grinding tool  10  serves in particular for grinding longitudinal profiles and longitudinal recesses. To this end the form profile  16  and the assigned grinding means  18  are supported exchangeably at the holder  12  as will explained in more detail in the following. The shape of the form profile  16  expediently is adjusted to the longitudinal profile that is to be ground. Thus different form profiles with different cross sections may be provided which are secured exchangeably to the holder  12 . In the case shown in  FIG. 1  the form profile  16  comprises several flat formed surfaces which are arranged at an angle to each other. Herein a plane designed front face  19  of the form profile  16  extends perpendicularly to the longitudinal axis  24  of the drive shaft  22 , and thus also perpendicularly to the longitudinal axis  60  which is defined by the support  14  of the holder  12 . 
         [0069]    The more detailed design of the grinding tool  10  now will be explained with reference to  FIGS. 3 to 8 . 
         [0070]    From  FIGS. 3 a -3 c    it can be seen that the grinding tool  10  is made up at least of two parts, possibly of three parts. In any case to this end a holder  12  with a support  14  is configured for connection with the drive spindle  22  ( FIG. 2 ). At the holder  12  the form profile  16  together with a suitably shaped grinding means  18  being configured as a grinding paper can be secured. The form profile  16  according to a first design at its surface may be provided with a grinding agent to thus allow a grinding directly with the form profile  16 . Alternatively also a separate grinding means  18  configured as a grinding paper may be provided, the shape of which is adapted to the shape of form profile  16  and which can be secured together therewith at the holder  12 . 
         [0071]    The holder  12  consists of a rigid plastic material and comprises a clamping region  36  having a cavity  38  into which the form profile  16  can be inserted with an assigned holding section  40  and can be secured thereto. To ensure a force transmittance between the drive spindle  22  and the holder  12 , within the support  14  a driving disk  30  made of metal, in particular of steel, is molded (cf.,  FIG. 1, 3, 7, 8 ) that allows for a positive force transmittance to the drive spindle  22 . To this end suitable recesses  32  are provided at the driving disk. 
         [0072]    The clamping region  36  comprises two side sections  46 ,  48  facing each other which are connected in one piece with the holder  12 . The axial ends of the cavity  38  are closed by end sections  42 ,  44 , wherein respectively one flat end face and two side extensions  53 ,  54  facing each other are provided. Between the end sections  43 ,  44  the side sections  46 ,  48  are enclosed which each are divided from the end sections  42 ,  44  by a slot  66 . This leads to the consequence that the two side sections  46 ,  48  facing each other that are only connected at there inner ends with the holder  12  can be enlarged relative to each other. 
         [0073]    To this end at the first side section  46  there are provided two gripping parts  50 ,  51  extending slanted to the outside. In case pressure is exerted onto the gripping parts  50 ,  51  from the outside, then the first side section  46  can be slightly widened to the outside relative to the second side section  48  to thus allow an insertion of the form profile  16  into the cavity  38  of the holder, or a withdrawal of the form profile  16  with its holding section  40  from the cavity  38 . 
         [0074]    In addition at the inner surfaces of the first side section  46  and the second side section  48  there may be provided webs  56  extending in insertion direction of the form profile  16 , to which respective grooves  58  are assigned at the holding section  40  of the holder  12 . 
         [0075]    In this way during insertion of the form profile  16  with its holding section  40  into the cavity  38  of the holder  12 , a positive support is made possible which impedes a shifting of the form profile  16  in longitudinal direction. 
         [0076]    If the form profile  16  shall be inserted with its holding section  40  into the cavity  38  of the holder, only pressure must be exerted onto the two gripping parts  50 ,  51 , whereby the first side section  46  enlarges to the outside relatively to the second side section  48 . 
         [0077]    Now the form profile  16  can be slid with its holding section  40  into the cavity  38  and is guided herein by the grooves  58  and the assigned webs  56 . If the form profile  16  is slid sufficiently deep into the cavity  38  or abuts therein, then the gripping parts  50 ,  51  are released, whereby the form profile  16  is safely secured within the clamping region  36  under the action of the internal stress of the clamping region  36 . 
         [0078]    If a separate grinding means  18  configured as a grinding paper according to  FIG. 3 c    is used, then this comprises a flat contour according to  FIG. 3 c    which preferably at both side faces facing each other is pressed into a recess  64  ( FIG. 1 ) which is shaped so that the two side sections  46 ,  48  of the holder  12  can directly interfere to thus ensure a safe securement of the grinding means  18 . The grinding means to this end is placed onto the form profile  16  and is inserted together therewith into the widened clamping region  36  of the cavity  38 , and thus is secured together with the form profile  16 . Herein the shape of the grinding means  18  adjusts to the outer shape of the form profile  16 . 
         [0079]    The form profile  16  preferably consists of a yielding plastic foam, such as a polyurethane foam, to allow for a suitable yielding of the form profile during grinding. 
         [0080]    While  FIG. 6  shows the holder  12  from the bottom without the adaptor  30 , from  FIG. 7  a longitudinal section and from  FIG. 8  a perspective longitudinal section through the grinding tool  10  can be seen. 
         [0081]    As can be seen in particular from  FIGS. 5 to 8 , the first side section  46  is received at the body of the holder  14  with a bent section  68  which subsequently yields into a flat section  70 . The opposite second side section  48  comprises a flat section  72  facing the first flat section  70  and at its inner end has a stop  74  formed perpendicularly therein serving as a stop when inserting the form profile  16 . 
         [0082]    The holder  12  is prepared as an injection molded part from a rigid plastic material (e.g. PVC). Thus a cost effective manufacture at high quantities and the same time an elasticity of the clamping region  36  is made possible.

Technology Classification (CPC): 1