Abstract:
A grinding or polishing disc which in addition to having improved viewing areas so that the object can be appropriately and clearly viewed as it is being ground or polished, also has vertical fins which create an airflow vortex similar to a turbine that go into the viewing locations to provide a cooling airflow to the workpiece so that in addition to being able to see the workpiece, the airflow cools the workpiece as the disc is being rotated.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of grinding and polishing discs which are used in conjunction with grinding and polishing machines to grind and polish the surface of objects. The disc is used in conjunction with well-known grinding and polishing machines having a motor driven shaft which include an exhaust duct or hood for removing dust and debris. 
     2. Description of the Prior Art 
     The present inventor is the inventor of issued U.S. Pat. No. 7,377,837 issued on May 27, 2008 for “Grinding or Polishing Arrangement”. 
     Many forms of grinding and polishing machines and devices have been utilized in the past in a wide variety of applications. In general, all such grinding or polishing machines or devices incorporate a rotating grinding or polishing disc against which a workpiece that is to be ground or polished is positioned. Some of the machines or devices are fully automated; some are hand held devices; and some utilize a manual positioning of a workpiece against the rotating grinding or polishing disc. In general, such grinding or polishing machines in which the workpiece was manually positioned against the rotating grinding or polishing disc were characterized in that they generally comprised a housing in which an electrically powered motor was installed. The motor rotated a vertically oriented shaft and on the remote end of the output shaft there was mounted the grinding or polishing disc. The workpiece to be ground or polished was generally placed against the under side of the disc and the grinding or polishing was commenced on the surface of the workpiece. As the grinding or polishing continued, dust or particulate matter was generated by the abrasion of the grinding or polishing disc on the workpiece. A hood or duct was placed in close relationship to the workpiece and the hood or duct had an opening into which the dust or particulate matter was conducted to be removed to regions spaced from the grinding or polishing machine. In many applications, a vacuum generating pump or device was connected to the remote end of the duct to aid in the removal of the dust or particulate matter. 
     Such devices had several disadvantages. Since the workpiece was located under the rotating disc to be placed against the underside thereof, the view of the workpiece was often obstructed by the disc. Some prior art discs had a few, narrow radial apertures in regions adjacent the outer periphery of the disc and a small portion of the workpiece was visible therethrough during the grinding or polishing operation. However, very often the workpiece was removed from engagement with the disc at various times in order to inspect the condition of the workpiece and then the workpiece was replaced in the grinding or polishing relationship to the underside of the grinding or polishing disc. Further, the exhaust duct or hood was often not located in the position with respect to the workpiece to allow efficient removal of the dust or particulate matter. 
     Accordingly, there has long been a need for a grinding or polishing disc in which more of the surface of the workpiece that is being ground or polished may be visible and in which a larger portion of the dust or particulate matter generated during the grinding or polishing operation may be removed. 
     The previous invention of the present inventor identified and claimed in U.S. Pat. No. 7,377,837 addressed the issue of improving the visibility of the workpiece. However, the workpiece still became very hot and hard to handle. Therefore, in addition to improving the visibility of the workpiece, there is a significant need to provide a cooling vortex to enable the workpiece to be appropriately cooled in addition to being cooled while it is ground and polished. 
     SUMMARY OF THE INVENTION 
     The present invention is an improved grinding or polishing disc which in addition to having improved viewing areas so that the object can be appropriately and clearly viewed as it is being ground or polished, also has vertical fins which create an airflow vortex similar to a turbine that go into the viewing locations to provide a cooling airflow to the workpiece so that in addition to being able to see the workpiece, the airflow cools the workpiece as the disc is being rotated. 
     It is has been discovered according to the present invention that by incorporating a multiplicity of axial rotatable fins which are orientated at an angle which extend from a high point at the peripheral edge of the disc to an area where they are virtually in line with the surface of the disc at the location where airflow begins to accumulate, then the airflow which moves at a radially outward direction is forced into the openings of the slots in the disc so that the airflow flows down into the workpiece and therefore causes cooling air to cool the workpiece in addition to providing an improved viewing of the workpiece as the disc is being rotated. 
     When used in conjunction with a conventional prior art grinding machine, the present invention grinding or polishing disc is coupled to the remote end of the shaft and rotates therewith. According to the present invention, the grinding or polishing disc has a plurality of cuts or slots having a predetermined pattern and extending therethrough from the upper surface thereof to the lower surface thereof. The predetermined pattern is selected to allow greater visibility of the workpiece through the disc during the grinding or polishing operation than has heretofore been available with prior art grinding or polishing discs and still have the disc with sufficient structural integrity to withstand the intended grinding or polishing operation. That is, since there are a very large variety of materials from which the workpiece may be fabricated, a workpiece that does not require great force to be used in keeping the workpiece in contact with the underside of the disc during the grinding or polishing operation, the cuts or slots may be more extensive than for a workpiece that requires a comparatively great force to hold it against the grinding or polishing disc. 
     The grinding or polishing disc has a generally circular peripheral edge with an upper surface having a multiplicity of raised fins with arcuate fins radiating from the external circumference up toward the center of the disc where a raised platform is created adjacent the central hub which is attached to the shaft of a rotating motor. The grinding and polishing disc has openings which are both generally perpendicular to the circumference and extend in a straight line toward the center of the disc and also have arcuate slots which extend at an arc from the circumference toward the center of the disc but most importantly, the slots are separated by raised fins which create an air vortex similar to a turbine to cause air to rotate into the location of the slots and cool the workpiece while it is being ground. This is a significant improvement over the inventor&#39;s prior invention wherein all of the discs were essentially flat or may have had a tapered surface but none of which had the fins and the vortex to create the cooling air which cools the workpiece as it flows. 
     The bottom surface of the grinding or polishing disc is generally planar and extends to the peripheral edge of the disc. In the preferred embodiment of the present invention, the peripheral edge has a predetermined axial thickness so that there is structure and support for the grinding or polishing operation throughout the radial extent of the grinding or polishing disc. The grinding or polishing disc may be fabricated from a unitary grinding or polishing material or the grinding or polishing disc may be a laminate. In the embodiments of the present invention wherein there is a laminate disc, there may be provided a substrate or base member of metal or other rigid material and on the bottom surface thereof is the grinding or polishing material. 
     In the most preferred embodiment, the present invention is molded out of a single piece of resin or other hard plastic material which can withstand the rigors of grinding and polishing while being rotated at a very high speed. The grinding or polishing disc of the present invention may be mounted on a handheld grinding or polishing device, or on an automated grinding or polishing machine which is the preferred utilization of the present invention. 
     Further novel features and other objects of the present invention will become apparent from the following detailed description, discussion and the appended claims, taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring particularly to the drawings for the purpose of illustration only and not limitation, there is illustrated: 
         FIG. 1  is an illustration of a prior art grinding or polishing machine which utilizes the present invention improved grinding or polishing disc; 
         FIG. 2  is a top plan view of the present invention grinding or polishing disc; 
         FIG. 3  is a bottom perspective view of the present invention grinding or polishing disc with sandpaper on the bottom surface; 
         FIG. 4  is a top perspective view of the present invention grinding or polishing disc; and 
         FIG. 5  is a top perspective view of a rotating present invention grinding or polishing disc illustrating the airflow through the straight and arcuate slots. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Although specific embodiments of the present invention will now be described with reference to the drawings, it should be understood that such embodiments are by way of example only and merely illustrative of but a small number of the many possible specific embodiments which can represent applications of the principles of the present invention. Various changes and modifications obvious to one skilled in the art to which the present invention pertains are deemed to be within the spirit, scope and contemplation of the present invention as further defined in the appended claims. 
     Referring now to the drawings, a prior art embodiment of a grinding machine is illustrated in  FIG. 1 . The present invention disc  100  is used with the prior art grinding machine  10  for which a workpiece is held against the bottom surface of the rotating grinding or polishing disc  100  of the present invention and the grinding or polishing machine is stationary during the grinding and polishing operation. 
     The grinding or polishing machine  10  of the prior art embodiment has a housing  14  with a sidewall  12  and a base  16  which supports the embodiment of the machine  10  in a generally upright and vertical position. The generally upright position provides a vertical shaft  15  upon which the grinding or polishing disc  100  is mounted for rotation therewith about axis  17  which is aligned vertically and that is perpendicular to the base  16  as illustrated in  FIG. 1 . The housing  14  defines a cavity therein and contains in the cavity an electrically powered motor (not shown) of conventional design for rotating the shaft  16  and grinding or polishing disc of the present invention  100 . If desired, a gear box (not shown) may also be contained in the cavity defined by the housing  14  to increase or decrease the rotational speed of the motor and consequently the rotational speed of the grinding or polishing disc  100 . The gear box may also be of conventional design. The motor may be a constant speed or a variable speed motor as desired for particular applications. The shaft  15  passes through a top seal plate  20  that is coupled to the housing  14  and is provided to prevent the entry of dust or particulate matter into the interior of the housing  14 . 
     Referring to  FIGS. 2 through 5 , there is shown the grinding or polishing disc of the present invention. The grinding disc of the present invention has two beneficial effects, one of which previously existed in the inventor&#39;s prior invention protected in U.S. Pat. No. 7,377,837 which included improved viewing of the workpiece as the disc is grinding and the new features of having the raised fins to create an air vortex of an airflow that goes into the slots to cool the workpiece as it is being ground. The disc  100  has a peripheral edge  200  that is generally circular in shape. The disc  100  also has an upper surface  110  and a lower surface  180 . The lower surface  180  is the surface which performs the grinding or polishing operation when a workpiece as indicated at  40  (see  FIG. 1 ) is pressed against a grinding material  182  affixed to the lower surface  180  of the disc  100  so that the upper surface  42  of the workpiece  40  may be ground or polished as desired. The grinding material  182  may be sandpaper or other abrasive material affixed to the lower surface  180  of the disc  100  and is cut to match the shape of the lower surface  180 . 
     The upper surface  110  of disc  100  has a generally flat or planar portion  120  which surrounds a central aperture  130  through which the disc  100  is coupled to the shaft of the grinding machine for rotation therewith. Initially, the upper portion of the disc has a vertical lip  132  which then transfers to a tapered section  140  which extends to approximately ⅕ the radius of the disc between the central vertical lip  132  and the exterior circumference  200 . An examination of the circumference of the disc  200  shows that it has a given thickness “T” which provides structural integrity to the disc  100  to withstand the forces involved with grinding and polishing. 
     In order to allow greater viewing of the workpiece  40  during the grinding or polishing operation, there are provided a plurality of apertures in the disc  100  extending from the upper surface  110  to the lower surface  180 . This will include 4 radial open slots  150 ,  152 ,  154  and  156  which extend from the exterior circumference  200  to approximately 40% of the radius of the disc. In addition to the straight slots and separating each of the straight slots are four generally arcuate open slots  160 ,  162 ,  164  and  166  which again extend from the exterior circumference  200  and extend in a radial arc of approximately 70 degrees and extend inwardly to a depth deeper than the straight slots so that the radial slots extend to approximately 50% of the radial length of the disc. The difference between this disc and the disc of the previous invention of the inventor identified and claimed in U.S. Pat. No. 7,377,837 is that instead of having a disc with a generally flat surface, the disc  100  extends to an entirely tapered design so that the taper goes from the vertical lip  132  to the exterior circumference  200  tapering at an even angle of approximately 45 degrees. 
     However, a key feature is that on the exterior surface of each disc section between the slots there are raising blades with elevated fins on exterior radial edges of the blades respectively adjacent a respective open slot. There are four wide spaced apart blades  210 ,  230 ,  250  and  270 , each having a generally flat section  212 ,  232 ,  252  and  272 , with each respective generally flat blade section ascending to a sloped section  214 ,  234 ,  254  an  274  which blend into the upper tapered section  300  which extends from the ascending sections to the transverse lip  132 . Each wide spaced apart blade has a pair of ascending fins on opposite radial edges of the wide blade. 
     First wide blade  210  has a first long fin  216  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  216  is adjacent a straight radial open slot  150 . On the opposite radial side of the first wide blade  210  is a second short fin  218  which extends from the circumference  200  to a location just beyond the innermost termination point of an adjacent arcuate open slot  160 . 
     The second short fin ends at the location where the upper tapered section  300  begins its upwardly tapered ascent toward the transverse lip  132 . There are four equally spaced apart width-wise blades  210 ,  230 ,  250  and  270  spaced approximately ninety (90) degrees apart. 
     Second wide blade  230  has a first long fin  236  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin is adjacent a straight open slot  152 . On the opposite radial side of the second wide blade  230  is a second short fin  238  which extends from the circumference  200  to a location just beyond the termination point of an adjacent arcuate open slot  162 . The second short fin  238  ends at the location where the upper tapered section  300  begins its upwardly tapered ascent toward the transverse lip  132 . 
     Third wide blade  250  has a first long fin  256  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  256  is adjacent a straight open slot  154 . On the opposite radial side of the third wide blade  250  is a second short fin  258  which extends from the circumference  200  to a location just beyond the innermost termination point of an adjacent arcuate open slot  164 . The second short fin ends at the location where the upper tapered section  300  begins its upwardly tapered ascent toward the transverse lip  132 . 
     Fourth wide blade  270  has a first long fin  276  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  276  is adjacent a straight open slot  156 . On the opposite radial side of fourth wide blade  270  is a second short fin  278  which extends from the circumference  200  to a location just beyond the inward termination point of an adjacent arcuate open slot  166 . The second short fin  278  ends at the location where the upper tapered section  300  begins its upwardly tapered ascent toward the transverse lip  132 . 
     There are four narrow spaced apart blades  220 ,  240 ,  260  and  280 , each having a generally flat section  222 ,  242 ,  262  and  282 , with each respective generally flat blade section ascending to a sloped section  224 ,  244 ,  264  an  284  which blend into the upper tapered section  300  which extends from the ascending section to the transverse lip  132 . Each narrow spaced apart blade has a pair of ascending fins on opposite radial edges of the narrow blade. 
     First narrow blade  220  has a first long fin  226  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  226  is adjacent a arcuate radial open slot  166 . and extends just beyond the innermost termination point of the adjacent arcuate open slot  166 . On the opposite radial side of the first narrow blade  220  is a second short fin  228  adjacent straight open slot  150  and which extends from the circumference  200  to a location just beyond the innermost termination point of the adjacent straight open slot  150 . 
     Second narrow blade  240  has a first long fin  246  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  246  is adjacent an arcuate radial open slot  160  and extends just beyond the innermost termination point of the adjacent arcuate open slot  160 . On the opposite radial side of the second narrow blade  240  is a second short fin  248  adjacent straight open slot  152  and which extends from the circumference  200  to a location just beyond the innermost termination point of the adjacent straight open slot  152 . 
     Third narrow blade  260  has a first long fin  266  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  266  is adjacent a arcuate radial open slot  162  and extends just beyond the innermost termination point of the adjacent arcuate open slot  162 . On the opposite radial side of the third narrow blade  260  is a second short fin  268  adjacent straight open slot  154  and which extends from the circumference  200  to a location just beyond the innermost termination point of the adjacent straight open slot  154 , 
     Fourth narrow blade  280  has a first long fin  286  which extends from the circumference  200  over the upper tapered section  300  to a location adjacent the transverse lip  132 . The first long fin  286  is adjacent an arcuate radial open slot  164  and extends just beyond the innermost termination point of the adjacent arcuate open slot  164 . On the opposite radial side of the second narrow blade  280  is a second short fin  288  adjacent straight open slot  156  and which extends from the circumference  200  to a location just beyond the innermost termination point of the adjacent straight open slot  156 . 
     Therefore, the present invention comprises a multiplicity of wide blades which are spaced apart by approximately ninety degrees and a multiplicity of narrow blades which are spaced apart by ninety degrees, the grinding disc having alternating wide blades and narrow blades, with four spaced apart straight open slot and four spaced apart arcuate open slots, each straight open slot between a short fin of a narrow blade and a long fin of a wide blade and each arcuate open slot between a short fin of a wide blade and a long fin of a narrow blade. 
     The airflow as illustrated in  FIG. 5  starts at the central hub  130  and extends along flat platform  120  and over transverse lip  132  and due to the orientation of the long fins and narrow fins adjacent respective straight open slots and arcuate open slots, the air is forced into the straight open slots  150 ,  152 ,  164  and  156  and arcuate open slots  160 ,  162 ,  164  and  166  so that cooling air is transmitted to the workpiece  40  adjacent the underside  180  and sandpaper  182  of the disc  100 . The wide blades with flat exterior surfaces and upwardly tapering interior surfaces and the narrow blades with flat exterior surfaces and upwardly taping interior surfaces create a turbine-like vortex which forces the cooling air out of the open slots and prevents the cooling air from flowing over the narrow blades and wide blades where it will have no cooling effect. 
     With the improvement of the present invention having a multiplicity of raised fins located between the straight and arcuate slots, an air vortex is created wherein air is forced by the raised fins into the straight and arcuate slots to provide cooling air to the workpiece to cause the workpiece to be much cooler as it is being ground. This is in addition to the improved viewing afforded by the straight and arcuate slots in the disc. 
     Therefore, based on the present invention, in addition to having the viewing substantially improved, the disc also provides for improved cooling of the workpiece. 
     Of course the present invention is not intended to be restricted to any particular form or arrangement, or any specific embodiment, or any specific use, disclosed herein, since the same may be modified in various particulars or relations without departing from the spirit or scope of the claimed invention hereinabove shown and described of which the apparatus or method shown is intended only for illustration and disclosure of an operative embodiment and not to show all of the various forms or modifications in which this invention might be embodied or operated.