Abstract:
A rotary finishing device includes a generally circular hub having a front surface, a back surface, an inner periphery and an outer periphery. The inner periphery of the device defines a throughhole. The front surface of the hub has a plurality of slots formed therein. Each of the plurality of slots has a plurality of finishing sheets secured therein by an adhesive. Each of the finishing sheets is of sufficient length such that when the generally circular hub rotates at a slower speed, the plurality of sheets remain within the outer periphery of the generally circular hub and provide a relatively flexible device for contacting a surface to be finished. Further, when the generally circular hub rotates at a higher speed, the plurality of sheets extend beyond the outer periphery of the generally circular hub and provide a relatively stiff device for contacting a surface to be finished.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present invention claims priority from U.S. Provisional Application Ser. No. 60/588,402, filed Jul. 15, 2004 and entitled “Rotary Finishing Device.” 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates generally to a rotary finishing device, and more particularly to a rotary finishing device for improving the finish of a wide variety of different surfaces having different shapes and contours.  
       BACKGROUND OF THE INVENTION  
       [0003]     Tools for leveling the surfaces of parts to be finished are well known. One such tool known in the art is commonly referred to as a flap disc. This type of leveling tool consists of a backing plate constructed of a plastic, aluminum or fiberglass material. The backing plate has a plurality of sheets of abrasive media, such as sandpaper, adhered thereto by epoxy. Each of the individual sheets is disposed within a respective slot formed in the backing plate or surface mounted to the backing plate. Additionally, each of the sheets is positioned on the backing plate such that the width of each sheet is substantially longer than its length. This configuration of the sheets with respect to the backing plate provides a stiff and relatively inflexible configuration, which yields a leveling wheel that operates similar to a belt sander in that it removes material from the surface it contacts in a planar fashion in order to flatten it.  
         [0004]     One significant disadvantage of these leveling tools is that they are unable to effectively contact the entirety of surfaces to be finished due primarily to their stiff and inflexible configuration. For example, known leveling tools cannot effectively contact curved surfaces or right-angled surfaces. Moreover, attempts to contact these hard to reach places with a leveling tool often results in “edge cutting” marks being formed in the surface, which are undesirable.  
         [0005]     Accordingly, to improve the finish of these portions of the types of surfaces, which leveling tools cannot effectively accomplish, secondary tools or processes need to be employed. These secondary finishing tools can include hand tools with various types of finishing media or, alternatively, a flap wheel. Employing these secondary processes increases the labor time by requiring the utilization of multiple different finishing tools to finish each different surface. This also increases the costs associated therewith.  
         [0006]     A typical flap wheel differs from a leveling wheel in that the flap wheel is intended to finish a surface instead of leveling or flattening it. Typical flap wheels include a central hub portion and have a plurality of flexible finishing strips secured thereto and extending from the outer periphery thereof. Because of their configuration, these flap wheel-type rotary finishing devices are also limited in the types of surfaces they can successfully and efficiently finish.  
         [0007]     Because of the disadvantages present with existing rotary finishing devices, in order to improve the finish of a metal surface having a variety of contours such as a wheel rim or a surface having right angles, multiple tools typically need to be utilized to finish it efficiently. To the extent a single device can finish the surface, the surface finish is likely not uniform.  
         [0008]     Therefore, a need exists for a rotary finishing device that is more flexible than existing finishing devices and can finish more areas on compound surfaces than existing products. In other words, a need exists for a rotary finishing device for finishing surfaces that can accomplish, in many instances, what currently requires multiple tools.  
       SUMMARY OF THE INVENTION  
       [0009]     It is therefore an advantage of the present invention is to provide a rotary finishing device that is more flexible than prior rotary finishing devices in that it can finish a wide variety of different surfaces, which have varying contours, including complex curves, concave surfaces and right angled surfaces.  
         [0010]     It is a related advantage of the present invention to provide a rotary finishing device that can finish surfaces that are constructed of different materials, including metal and non-metal.  
         [0011]     Another advantage of the present invention is to provide a rotary finishing device that increases the efficiency associated with finishing a product having a complex surface, a concave surface and/or a right-angled surface.  
         [0012]     Yet another advantage of the present invention is to provide a rotary finishing device that decreases the time required to finish a product having a complex surface, a concave surface and/or a right-angled surface and therefore provides decreased cost.  
         [0013]     Still another advantage of the present invention is to provide a rotary finishing device that can easily change the surface finish of a piece being finished by changing the rotational speed of the device.  
         [0014]     It is still a further advantage of the present invention to provide a rotary finishing device that is more durable and has a significantly longer useful life than existing rotary finishing devices.  
         [0015]     It is yet a further advantage of the present invention to provide a rotary finishing device with an effective diameter that varies with the rotational speed of the device.  
         [0016]     It is a related advantage of the present invention to provide a rotary finishing device with an effective diameter that increases as the rotational speed of the device increases.  
         [0017]     It is still yet another advantage of the present invention to provide a rotary finishing device with attached finishing media having a length that is greater than this width.  
         [0018]     In accordance with the above and the other advantages of the present invention, a rotary finishing device is provided. The rotary finishing device includes a backing plate having an inner face and an outer face. The backing plate is coupled to a drive shaft to allow rotation of the device as desired and at a desired speed, which can vary. The inner face of the backing plate has one or more sheets of finishing media secured thereto and extending therefrom. Each of the sheets is configured such that it has a length at least as long as the width. In another embodiment, the length of the finishing strips is at least twice as great as the width.  
         [0019]     The sheets are flexible and thus flatten or fan out as the device is rotated. The faster the device is rotated, the flatter the finishing media becomes, which provides a stiff finishing tool. The slower the device is rotated, the more flexible the finishing media becomes to allow finishing of a contoured surface. The effective contact area or diameter of the device thus changes or varies with the rotational speed.  
         [0020]     Other advantages of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     For a more complete understanding of this invention, reference should now be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention:  
         [0022]      FIG. 1  is a perspective view of a rotary finishing device, in accordance with one embodiment of the present invention.  
         [0023]      FIG. 2  is another perspective view of the rotary finishing device shown in  FIG. 1 .  
         [0024]      FIG. 3  is a front view of the rotary finishing device of  FIG. 1  illustrating the orientation of the finishing media when the device is rotating at a higher speed.  
         [0025]      FIG. 4  is a perspective view of the rotary finishing device of  FIG. 1  illustrating the orientation of the finishing media upon contact with a surface when the device is rotating at a lower speed.  
         [0026]      FIG. 5  is a perspective view of a rotary finishing device in accordance with one embodiment of the present invention.  
         [0027]      FIG. 6  is another perspective view of the rotary finishing device of  FIG. 5 .  
         [0028]      FIG. 7  is a schematic illustration of a rotary finishing device illustrating changes in the effective contact area or diameter of the device.  
         [0029]      FIG. 8   a  is an illustration of a finishing media sheet in accordance with one embodiment of the present invention.  
         [0030]      FIG. 8   b  is an illustration of a finishing sheet in accordance with another embodiment of the present invention.  
         [0031]      FIG. 8   c  is an illustration of a finishing sheet in accordance with yet another embodiment of the present invention.  
         [0032]      FIG. 9  is an illustration of a rotary finishing device rotating at a relatively slow speed in accordance with one embodiment of the present invention.  
         [0033]      FIG. 10  is an illustration of the device of  FIG. 9  rotating at a medium speed.  
         [0034]      FIG. 11  is an illustration of the device of  FIG. 9  rotating at a relatively fast speed. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]     Referring now to the Figures, which illustrate various embodiments of a rotary finishing device in accordance with the present invention. The rotary finishing device disclosed herein can be utilized to finish a surface, such as by polishing, abrading, grinding or the like. However, it will be understood that the finishing devices disclosed herein can be utilized for a variety of different purposes and can be formed with a variety of different configurations.  
         [0036]     The finishing media utilized with the disclosed finishing devices can also vary depending upon the application for which the finishing devices will be used and can include cloth, sandpaper or the like. Further, the finishing media may be a textile sheet, a woven sheet, a non-woven sheet, or a neo-textile sheet. The finishing media may also be a coated abrasive sheet. It will also be understood that a variety of other different finishing media may be utilized. The disclosed finishing device can be utilized to finish pieces constructed of a wide range of different materials, including metal, wood and a variety of other materials.  
         [0037]     Turning now to  FIGS. 1 and 2 , which illustrate one embodiment of a rotary finishing device in accordance with the present invention. The rotary finishing device  10  includes a generally circular backing plate  12 , having an outer peripheral surface or outer periphery  14  and a passageway or throughway (arbor hole)  16  formed generally through the backing plate  12 . The passageway  16  is preferably a threaded bore for ease of coupling to a driving shaft (not shown) by threaded engagement. However, it will also be understood that the passageway  16  may also remain smooth without threads and may be attached to a driving shaft in other suitable fashions. The backing plate  12  has an outer face  18  and an inner face  20 . The driving shaft is coupled to the backing plate  12  through the passageway  16  to allow for rotation of the backing plate about an axis of rotation of the device  10 , which corresponds to the centerline of the backing plate  12 .  
         [0038]     While the illustrated backing plate has a generally circular construction, it will be understood by one of ordinary skill in the art that a variety of other suitable configurations or shapes may be utilized. The backing plate  12  is preferably formed from a metal, such as aluminum, and is preferably formed by an extrusion process. However, it will also be understood that a variety of other materials may also be utilized to form the backing plate  12 , including plastic. The backing plate  12  may also be formed in a variety of other suitable processes. It will also be understood by one of ordinary skill in the art that the backing plate  12  can be formed in a variety of different diameters to provide finishing devices of a variety of different sizes. The backing plate  12  may also have a variety of different thickness and a variety of different shapes.  
         [0039]     The inner face  20  of the device  10  includes a plurality of slots  24  formed therein. In the embodiment of  FIGS. 1 and 2 , the slots  24  each constitute a groove or recesses or even a flat surface formed in the inner face  20  of the backing plate  12 . In the embodiment of  FIGS. 5 and 6 , the plurality of slots  24  are formed entirely through the backing plate  12 , such that they are open to both the outer face  18  and the inner face  20 . In the embodiment where slots are utilized, the shape of the slots  24  is preferably generally rectangular. However, it will be understood that the slots  24  can take on a variety of different shapes, can be formed in a variety of different sizes, including oval, and can be formed of a variety of different depths. Additionally, the slots  24  may have a variety of orientations, including angled. It will also be understood that other structures instead of slots may be utilized. Moreover, slots may be omitted from the backing plate  12  altogether.  
         [0040]     As shown, each of the slots  24  includes a finishing media  30  disposed therein. The finishing media  30  may be comprised of a single sheet of finishing material or, more preferably, of a plurality of sheets of finishing material (“a pack”). The finishing media  30  is intended to contact a surface to be finished. A pack of finishing media  30  is preferably disposed within each of the plurality of slots  24  such that the finishing media  30  contacts at least either side  26 ,  28  of each of the plurality of slots  24  such that the pack is wedged in each slot. The finishing media  30  can be disposed in each of the plurality of slots in a variety of different ways. The finishing media  30  is preferably secured within each of the slots  24  by an adhesive, such as an epoxy. Obviously, the finishing media  30  can be secured within each of the slots  24  by a variety of other suitable methods including by mechanical attachment. The finishing media  30  may also be secured to the backing plate  12  by alternate suitable methods.  
         [0041]     As shown best in  FIG. 2 , the finishing media  30  that are disposed in each of the slots  24  preferably consist of a plurality of individual sheets  32 , which together form a pack. In this embodiment, each of the sheets  32  within the pack consists of an abrasive paper, such as sandpaper. However, as discussed above, other finishing media  30  may be utilized. As also shown, in this embodiment, each pack is divided into two sections. The first section  34   a  faces in one direction while the second section  34   b  faces in the other direction. In other words, the abrasive part of the sandpaper is facing in one direction in one pack  34   a  and in the other direction in the other pack  34   b . This allows the finishing media  30  to finish a surface of a piece when the backing plate  12  is rotated in either the clockwise or counterclockwise direction. It will be understood that in another embodiment, the grit of the sandpaper in the first section  34   a  may be different from the grit of the sandpaper in the second section  34   b . This will provide varying abrasiveness depending upon the direction in which the device is rotating. It will also be understood that all the sheets in a pack can face in the same direction. Further, sandpaper having grit on each side thereof may also be utilized.  
         [0042]     As shown in  FIG. 3 , because the packs of finishing media  30  are flexible, they will flatten out, such as by bending in a somewhat butterfly fashion, when the device  10  is rotating.  FIG. 3  generally illustrates the configuration of the rotary finishing device  10  when it is rotating at a higher rate of speed. The faster the backing plate rotates, the flatter the device  10  becomes. Additionally, the faster the backing plate  12  rotates, the stiffer the device  10  becomes, which provides a harder finishing device. This is due to the configuration of the finishing media  30  as discussed in more detail below. A stiff device is desirable for some surfaces. Similarly, as the backing plate  12  rotates at a slower speed, the device  10  remains relatively flexible and provides a softer finishing device. A flexible device provides a surface finish that is desirable for many applications as will be understood by one of ordinary skill.  FIGS. 9 through 11  illustrate the variance in the flattening out of the device and the finishing media  30  as the rotational speed of the device  10  increases.  
         [0043]      FIG. 9  illustrates the finishing device  10  attached to a driving shaft and rotating. The device  10  in  FIG. 9  is rotating at a relatively slow speed as evidenced by the fact that the finishing media  30  extends in a generally planar orientation from the backing plate  12  (i.e. perpendicular to the inner face  20  of the backing plate  12 ). In this orientation, the device  10  is relatively flexible.  FIG. 10  illustrates the device  10  rotating at a generally medium speed. At this faster speed, the finishing media  30  have begun to flatten out, which increases the effective diameter of the device  10 .  FIG. 11  illustrates the finishing device  10  rotating at a higher speed where the finishing media  30  have flattened out significantly. At this speed, the effective diameter of the device  10  has increased even more than in  FIG. 10 . Additionally, in this orientation, the device  10  is relatively stiff.  
         [0044]      FIG. 4  illustrates how the rotary device  10  contacts a surface and follows it as the device  10  is moved therealong. This allows for the finishing of surfaces having various contours such as a fuel tank, a wheel rim, or a part, pan or other concave surface. This is, at least in part, because the finishing media  30  are relatively flexible and can follow the contour of surface as the device  10  travels thereacross. Because the packs are more flexible, they can take on different lengths and reach into openings, grooves, or contours that would not otherwise be accessible without a smaller tool. This is because each pack of sheets can act as its own finishing device and follow the surface of the part due, at least in part, to its flexibility.  
         [0045]      FIG. 7  schematically illustrates the flattening out of the finishing media as the device  10  rotates. As shown in the static position, the packs of finishing media  30  are oriented such that they lie within the outer periphery  14  of the backing plate  12  before the device begins to rotate, as generally indicated by reference number  50 . Because the sheets of finishing media  30  are flexible, they flatten out and expand, such that the device  10  has an increased diameter or contact area as the rotational speed of the device  10  increases. For example, as the device  10  begins to rotate at a low speed, the effective diameter of the device  10  increases to a size generally indicated by reference number  52 , which is larger than or expanded with respect to the initial diameter  50 . As the device  10  rotates at faster speeds, the finishing media  30 , due in part to centrifugal force, increases the effective diameter of the device even further, as generally indicated by reference number  54 . As the device  10  rotates at an even higher RPM, the effective diameter will increase more depending upon the rotational speed of the device  10 . The configuration of the device  10  illustrated in the Figures is merely exemplary and not to be construed as limiting. The device  10  is particularly suitable for use in robotic applications where the speed and direction of the device  10  can be readily changed through computer control. This allows the device  10  of the present invention to finish compound surfaces by varying the rotational speed of the device as opposed to prior methods, which required the utilization of multiple devices.  
         [0046]      FIGS. 8   a  through  8   c  schematically illustrate exemplary configurations of a sheet of finishing media  30  in accordance with the present invention. The configuration of the finishing media  30  as attached to the backing plate provides the disclosed finishing device  10  with unique flexibility that allows for the finishing of surfaces such as right edge surfaces and concave-type surfaces. As shown in  FIG. 8   a  the sheet of finishing media is configured such that its width (w) is about equal to its length (l).  FIG. 8   b  illustrates another embodiment where the length (l) of the finishing media is at least twice as large as the width, (w≦2 l).  FIG. 8   c  illustrates yet another embodiment where the length (l) of the finishing media is at least three times as great as the width (w≦3 l). It will be understood that the dimensional relationship between the length and the width can take on a variety of different configurations.  
         [0047]     While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.