Abstract:
The present invention is a finishing plate and method of fabricating a finishing plate. The finishing plate can be fabricated to various shapes, and can be used with various surfacing machines. In a preferred mode, the present invention is a disc cutting plate which can be used with a random orbital sander, and can be used to replace traditional abrasive sheets such as sandpaper. The present invention can be used in smoothing various materials including wood, painted wood, plastic, and various metals.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Application No. 60/880,725, filed Jan. 17, 2007. 
    
    
     SEQUENCE LISTING 
     Not Applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Various means are available for mechanically smoothing the surfaces of materials. Rotary, vibratory, belt and orbital sanders, have various sanding surface shapes and sizes, and are often used for this purpose. The invention is described in terms of its application to random orbital sanders, rotary sanders, and orbital sanders. However, application to any surfacing machine is included in the field of the invention. 
     2. Description of Related Art 
     In the field of surface finishing, workers use various types of powered and manual abrading methods. In most cases, a worker will use replaceable sandpaper pads in conjunction with reciprocating or orbital machines. Generally, these methods produce a satisfactory finish on woods, painted woods, plastics or metals. 
     A problem faced by such workers is the cost associated with constantly replacing sand paper. These costs can mount both in the expense of the pads and in the time required to replace. The replacement time can be considerable, as workers often must traverse ladders and locate fresh pads. Moreover, as traditional abrading devices wear, they provide variable finish, which is not desirable. For example, a 40-grit sandpaper can start its useful life providing a proper coarse finish. However, the grit level immediately begins to degrade when the pad use begins. The 40-grit might perform like an 80-grit when the replacement time arrives. 
     The prior art is replete with abrasives attached to flexible sheets. As an example,  FIG. 1  illustrates the use of flexible sheets  30  coated with sheet back side  33  on one side with adhesive applied to the sheet back side  33 . The flexible sheet  30  attached to the platen  31  of a manually operated or handheld orbital sander  13 , which are known in the art of smoothing the surfaces of hard and soft materials. When smoothing soft material surfaces or low melting point surfaces, the sheet back side  33  becomes easily clogged with waste or amorphous material that can not be removed, resulting in premature failure and replacement. When smoothing hard material surfaces the sheet back side  33  often breaks down and loses the ability to remove material from the material surface resulting in premature failure and replacement. When smoothing soft and hard material surfaces simultaneously, i.e. a nail in a piece of wood, the flexible sheet  30  often tears also resulting in premature failure and replacement. 
       FIG. 2  illustrates advances over that of the flexible sheet  30  art that have addressed convenience and ease of replacement. A flexible sheet of metal  34  has one rough surface  35  and one flat surface having Velcro™  36  adhesively attached thereto. Velcro™  36  is also applied to the platen of the manually operated or handheld orbital sander  13 . Although this advance addresses the issues of premature failure experienced with the coated flexible sheet  30  art, many performance, effectiveness, productivity, efficiency and convenience issues are not addressed. 
     Moreover, various attempts have been made in using metallic and other rigid cutters or abrasive discs. By way of example, U.S. Pat. No. 1,411,936 to Salata discloses a filing machine and U.S. Pat. No. 2,043,509 to Easters discloses a metal and wood surfacing tool. (936) to Salata shows only a device for reciprocating a conventional metal file back and forth, and is thus not intended for a random orbital machine. (509) to Easters shows a rotary filing machine which may work on wood. However, the complexity of the roller mechanism will make it susceptible to failure due to debris entering the machine. 
     A simpler method of facing a surface that alleviates the problems above is to attach files to rotary discs or to form file patterns in rotary discs. By way of example, U.S. Pat. No. 992,437 to Metcalf discloses a rotary file. U.S. Pat. No. 3,086,277 to Hardy discloses an abrasive finishing disk. U.S. Pat. No. 2,768,422 to McKenna discloses a file and method of making the same. U.S. Pat. No. 2,994,942 to Harvell discloses a motor operated vehicle body and fender file. U.S. Pat. No. 4,639,989 to Filby discloses a sanding tool. U.S. Pat. No. 5,056,203 to Miller shows an abrading and cutting tool assembly. U.S. Pat. No. 3,165,813 to Harvell discloses a rotary file. (989) to Filby provides a series of saw type blades on a rotary disc which may be used in conjunction with an orbital sander. However, the sparsely located teeth could not be used to provide a smooth finish on a wood surface. (277) to Hardy and (942) to Harvell show rotary files with replaceable cutters. They do not however, show rotary devices which are used for simultaneous smoothing and cutting. (422) to McKenna, (203) to Miller and (803) to Harvell show rotary files with continuous patterns. These devices cannot however be used to both remove and smooth material simultaneously. 
     A number of cutters and abraders have been combined with quick fasteners for rapid replacement of worn or damaged tools. By way of example, U.S. Pat. No. 4,423,571 to Selander discloses a quick change shoe assembly for a straight line sander. U.S. Pat. No. 5,967,886 to Wuensch discloses a hand power tool for flat machining. U.S. Pat. No. 5,123,139 to Leppert shows a buffing pad assembly. None of the above devices, however show a finishing plate which when used on a random orbital sander can both remove material and smooth material simultaneously. 
     To address the need to move an abrading device into a corner, a number of different shapes have been used. By way of example, U.S. Pat. No. 5,398,457 to Updegrave shows an edge and corner sanding attachment. This device, however does not show a hardened steel disc with multiple lines of cutting blades. 
     To address the shortcomings of traditional abrasive pads, abrasive manufacturers have also developed a number of structured abrasive products. By way of example, U.S. Published Application Number 20070254560 to Woo shows a structured abrasive article. While these systems provide certain benefits over traditional abrasives, they also have certain drawbacks. Since the points are “pyramidal” rather than angled, they cannot be used for simultaneous smoothing and cutting. Moreover, since they are abrasive, they work by way of friction. The same friction which causes the system to work also causes particles to build up, and thereby lose effectiveness. If the system comprised a series of smooth hardened cutting blades, the particle buildup problem could be alleviated because the blade relief surface would provide a low friction channel for debris to escape. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention applies material and process technology developed for life time cutlery blades to provide a finishing plate to improve surface smoothing productivity. More specifically, the present invention is a finishing plate and method of fabricating said finishing plate which is used with various surfacing machines. In particular, the present invention can be manufactured as a disc cutting plate, a mouse cutting plate or other plates of various geometries. The surfacing machines which can be used include, but are not limited to: random orbital sanders, orbital sanders, vibratory sanders, and handheld power drills. 
     The finishing plate of the present invention can be used in finishing various materials including, but not limited to: wood, painted wood, varnished wood, plastic, aluminum, steel and other metals. 
     In a preferred embodiment, the finishing plate is essentially a round flat steel disc, or a disc cutting plate. The disc cutting plate has a first blade set and a second blade set. If desired, more blade sets could be added. Each blade set consists of parallel cutting blades ground into the disc cutting plate with a pitch of approximately 1/16″ and blade depth of approximately 0.02″ A cutting blade comprises three surfaces: a front rake surface, a blade relief surface and a back blade surface. The back blade surface is parallel to the disc back surface, and the front rake surface is orthogonal to the blade relief surface, and the back blade surface extends at approximately 45 degree angle to the blade relief surface of the adjacent blade. 
     Since each cutting blade in the blade set is linear and parallel to adjacent cutting blades, the cutting blades appear geometrically as chords on the circle created by the periphery of the disc cutting plate. And since the cutting blades have one cutting surface or front rake surface, some blades approach material on the workpiece with the front rake surface leading. Other cutting blades approach the workpiece with the blade back surface in the lead. Still other cutting blades approach the workpiece with varying angles of cutting or back areas in the lead. This affect provides for some cutting blades shearing material, while others smooth material. As cutting blades on one side are removing material, cutting blades on the other side smooth material. 
     In operation, the user would secure the disc cutting plate to a random orbital sander. He or she would start the sander and place it on the work piece. As the cutting blades are simultaneously rotated and orbited, the user would feel a slight pull from one direction to another as the cutting blades pass. As previously described, while cutting blades on one side of the disc cutting plate are shearing material, cutting blades on the opposite side are smoothing material. And since the disc cutting plate is a hardened steel plate with a smooth finish, chips and debris slide easily along the blade relief surface until the chips &amp; debris are ejected out the side. This provides for significantly fewer clogging problems when compared to traditional abrasive pads. Moreover, since the disc cutting plate is hardened steel, or other hardenable material, it does not wear out quickly. In particular, if the disc cutting plate is hardened to Rockwell C 60-65, and the workpiece is wood, the disc cutting plate could last for 5-10 years. 
     The method of manufacturing this revolutionary disc cutting plate is described as follows. First a material, such as A2 tool steel is selected. Other materials, such as carbide, titanium, high speed steel, oil hardenable steel, or possibly even aluminum could be used. Next, a thin sheet of material—possibly 1/16″×6″ is placed in a “creep feed grinder”. The creep feed grinder has a grinding wheel with a profile that matches the blade set profile. So, when viewed from a direction that is orthogonal to the axis of the grinding wheel rotation, the inverse of an entire blade set would be seen along the top of the grinding wheel. Once secure in the machine, the grinding wheel is rotated about its own and a jet of grinder lubricating fluid is sprayed at the interface. The blank plate material is moved slowly beneath the grinding wheel. The blank material emerges after one pass with the first blade set ground into the plate front surface. The plate is then rotated 120 degrees, and the process is repeated. The resulting plate now has two blade sets ground into the front surface. 
     Next, the correct overall shape for the finishing plate is selected. In the preferred embodiment of this invention, this overall shape is a round disc. However, in a secondary embodiment, the shape known as the mouse could be selected. The mouse shape is the type which is used for finishing corner areas of floors. Other shapes are of course possible. 
     Finally, the finishing plate must be hardened. This process step depends on the material selected. In the case of A2 tool steel, the finishing plate can be hardened to over Rockwell C 60 by known methods of heating the steel to a certain temperature and allowing it to cool in air. Other possibilities exist for other materials. For example, aluminum could be hard anodized, or a tool steel could be quenched in a liquid. 
     There has thus been outlined the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. In as much as the foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description of the invention that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the disclosed specific methods and structures may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should be realized by those skilled in the art that such equivalent methods and structures do not depart from the spirit and scope of the invention as set forth in the appended claims. 
     In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
     As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
     Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
     Therefore, it is an object of the present invention to solve the aforementioned problems of the existing art particularly when applied to the smoothing of soft material surfaces such as wood or plastic having planar and certain non-planar surfaces. 
     It is also an object of the present invention to provide for the smoothing of surfaces of hard materials. 
     It is a further object of the present invention to provide for the smoothing soft and hard surfaces simultaneously. 
     It is a further object of the present invention to provide for simultaneous material removal and material smoothing. 
     Yet another object of the present invention is to provide a cutter which has uniform surface finishing characteristics over its lifetime. 
     It is yet another object of the present invention to provide a cutter which easily evacuates chips &amp; debris as it is being used. 
     Yet another object of the present invention is to provide a cutting surface that is not easily deflected during cutting. 
     Still another object of the present invention is to provide a finishing plate which provides a finish comparable to those found when using traditional abrasives such as sandpaper. 
     It is yet another object of the present invention to provide for a cutting device which lasts much longer than sandpaper. 
     It is yet another object of the present invention to provide for a cutting device which can be quickly removed from a power tool and replaced with another cutting device. 
     Still another object of the present invention is to provide a finishing plate which reduces the overall costs of performing traditional construction jobs. 
     Yet another object of the present invention is to provide a finishing plate manufacturing method whereby different finish smoothness can be achieved by altering the pitch and blade height of the cutting blades. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein: 
         FIG. 1 : Prior art showing a flexible sheet with an abrasive coating attached to a handheld vibratory or orbital sander. 
         FIG. 2 : Prior art showing a metallic sheet attached to a handheld vibratory or orbital sander. 
         FIG. 3   a - 3   f : Detail Views of the present invention formed as a Disc Cutting Plate. 
         FIG. 4   a - 4   f : Preferred embodiment of the present invention used on a random orbital Sander. 
         FIG. 5 : Secondary embodiment of the present invention used a handheld orbital sander, where the cutting plate is formed as a cornering mouse. 
         FIG. 6 : Preferred embodiment of the present invention with a center hole added for mounting to a handheld power drill. 
         FIG. 7 : Disc Cutting Plate with a Chamfer added to the outer periphery. 
         FIG. 8   a - 8   c : Side and End Views of the Creep feed Grinder and Grinding Wheel. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to  FIGS. 3  the present invention is shown in its preferred embodiment.  FIG. 3   a  shows a bottom view of a disc cutting plate  1 . In this embodiment, the disc cutting plate  1  can be used with a commercially available surface finishing machine having a platen that is circular. The disc cutting plate  1  is made of a hard material, harden-able material or is coated with a hard coating for long blade life and low friction when performing a surface finishing operation on a surface. As seen in  FIG. 3   a  and  3   b , the disc cutting plate  1  has an essentially circular periphery and also a center locating hole  4 . The periphery can have a chamfer or radius on the plate outer edge to improve the surface quality of the surface being smoothed. Although the preferred method of attaching the disc cutting plate  1  to the surface finishing machine via hook &amp; loop material, other attachment means can be used, including adhesive or threaded fasteners. 
       FIG. 3   b  shows a cross section of disc cutting plate  1  through section “A-A” As seen, disc cutting plate  1  has a plate diameter  27  of approximately 5″ a first blade set  7  protruding therefrom. 
     Referring now to  FIG. 3   c  and  FIG. 3   f , where enlarged views of the disc cutting plate  1  are shown. The disc cutting plate  1  has a plate back surface  6  which is parallel to the surface being smoothed when in operation. Disc cutting plate  1  has a plate thickness  21  which can be approximately 1/16″, and plate thickness  21  is essentially unchanged over the entire disc cutting plate  1 . The cutting blade  2  can have blade height  22  of approximately 0.02″, and pitch  23  of approximately 0.06″. A front rake surface  3  extends from a blade tip  5  to a blade relief surface  9 . The blade relief surface  9  extends a distance of blade relief width  24  of approximately 0.04″. The front rake surface  3  is orthogonal to plate back surface  6 . A blade back surface  10  extends at back blade angle  25  of approximately 45 degree angle from the blade tip  5  to the blade relief surface  9  of the adjacent cutting blade  2 . Each cutting blade has an essentially equal blade relief width  24 . 
       FIG. 3   d  shows a cross section of disc cutting plate  1  through section “B-B” of the present invention. A second view of the cutting blades  2  viewed in this direction is substantially the same dimensions shown in  FIGS. 3   c  and  3   f.    
     Referring now to  FIG. 3   e , the disk cutting plate  1  has cutting blades  2  protruding from the blade relief surface  9 . Each of the cutting blades has two blade back surfaces  10  and two front rake surfaces  3 . There is a first cut rake surface  7  and a second cutting surface  8  on each cutting blade  2 . The two front rake surfaces  7  and  8  meet at blade crossing angle  26  of approximately 120 degrees. It is a appreciated that blade crossing angle  26  can be varied. Moreover, additional blade sets could be added at various other angles. 
     In experimentation the inventor has observed that the blade height  22  of 0.02″ and pitch  23  of 0.06″ provides a finish on the surface being smoothed which corresponds to coarse or 40 grit sandpaper. The pitch  23  of adjoining blades is illustrated as being essentially equal but may vary to facilitate special cutting requirements. Moreover, the blade height  22  and pitch  23  can be decreased to provide a finish on surface being smoothed which corresponds to fine or 80-120 grit sandpaper. 
     Referring now to  FIG. 4 , the preferred embodiment of the present invention is shown attached to the random orbital sander  12 . The disc cutting plate  1  is manufactured as shown in  FIG. 3   a - f .  FIG. 4   a  is a bottom view of the disc cutting plate, and  FIG. 4   b  is a sideview of the disc cutting plate  1  mounted to the random orbital sander  12 .  FIGS. 4   c - f  show side views of the cutting blade  2  interacting with the workpiece  11 . The random orbital sander  12  has a circular platen  17  which is covered with hook attachment  14  of the conventional type, commonly referred to as Velcro. Disc cutting plate  1  has mating loop attachment  15  for releasable attachment to the hook attachment  14  of round platen  17 . Once disc cutting plate  1  is secured to the round platen  17 , the random orbital sander  12  is activated. Prior to pressing on the workpiece  11 , the circular platen will rotate at a high rate of speed. Once pressure is applied to the workpiece  11  with disc cutting plate  1 , the circular platen rotational speed will slow, and the circular platen will move in an orbital motion of the type commonly known. The first cutting blades  7  and second cutting blades  8  will both remove chips &amp; debris  48  from the workpiece  11  and smooth workpiece  11 . 
     The simultaneous removal and smoothing will be better understood when referring to  FIG. 4   c - f . As seen in  FIG. 4   c , an enlarged side view of the first cutting blades  7  travels right to left as a result of the counter-clockwise rotation of the disc cutting plate  1 . Since the front rake surface  3  approaches the workpiece  11 , an amount of chips &amp; debris  48  are produced. Next, as seen in  FIG. 4   d  an enlarged side view of the second cutting blades  8  travels right to left as a result of the counter-clockwise rotation of the disc cutting plate  1 . Since the front rake surface  3  approaches the workpiece  11 , an amount of chips &amp; debris  48  are produced. Next, as seen in  FIG. 4   e , an enlarged side view of the first cutting blades  7  travels left to right as a result of the counter-clockwise rotation of the disc cutting plate  1 . Since the blade back surface  10  approaches the workpiece  11 , no chips &amp; debris are produced. Rather, the rubbing of the blade tip  5  and the blade back surface  10  on the workpiece  11  causes a smoothing effect on the workpiece  11 . Finally, as seen in  FIG. 4   f , an enlarged side view of the second cutting blades  8  travels left to right as a result of the counter-clockwise rotation of the disc cutting plate  1 . Since the blade back surface  10  approaches the workpiece  11 , no chip &amp; debris are produced. Rather, the rubbing of the blade tip  5  and the blade back surface  10  on the workpiece  11  causes a smoothing effect on the workpiece  11 . 
     Referring now to  FIG. 5 , a second embodiment of the present invention is shown. A finishing plate can be formed as a mouse cutting plate  16 . The mouse cutting plate  16  is manufactured with the same tooth profile as shown in  FIG. 3   a - e . Rather than manufacturing a round plate, the mouse cutting plate  16  has a corner profile which enables use in corners where disc cutting plate  1  could not reach. The hook attachment  14  is attached to the platen of a handheld orbital sander  13 . The loop attachment  15  is attached to the mouse cutting plate  16 . The hook attachment  14  and the loop attachment  15  together are also known as Velcro. 
     Referring now to  FIG. 6 , a third embodiment of the present invention is shown. A finishing plate can be formed as a second disc cutting plate  40 , which is substantially similar to the disc cutting plate  1 . A disc plate thru-hole  41  is added to the center of the second disc cutting plate  40 . A shaft mounting screw  20  is then inserted through the disc plate thru-hole  41 , and into stub shaft adapter  19 . The stub shaft adapter  19  is then tightened into the drill chuck  43  of a handheld power drill  18 . The present invention can then be used for various additional surfacing finishing operations including those where the user has only the handheld power drill  18  available. 
     Referring now to  FIG. 7 , the disc cutting plate  1  or the second disc cutting plate  40  can have an outer periphery chamfer  42  added around the entire outer edge. As seen, the cutting blade  2  will gradually be removed from an inner chamfer ring  59  to an outer disc edge  58 . With the outer periphery chamfer  42 , the disc cutting plate  1  and the second disc cutting plate  40  will have less tendency to dig into the workpiece  11  in the area of the outer disc edge  58 . 
     Referring now to  FIG. 8 , the manufacturing method and machinery are shown.  FIG. 8   a  shows the method,  FIG. 8   b  shows a side view of a creep feed grinder  51 , and  FIG. 8   c  shows an end view of the creep feed grinder  51 . First a blank sheet  46  is selected of appropriate cutter material  47 . Next, the blank sheet  46  is secured to the machine bed  52  of the creep feed grinder  51 . A grinding wheel  50  is secured to the spindle of the creep feed grinder  51 , and the grinding wheel  50  is rotated at an appropriate speed. Grinding fluid  54  is sprayed at a high speed toward the interface of grinding wheel  50  and blank sheet  46 . Next, the machine bed  52  is passed from left to right as seen in  FIG. 8   b . As seen in the end view  FIG. 8   c , the grinding wheel  50  has multiple grinding wheel teeth  53  which are the reverse of both the first blade set  7  and the second blade set  8 . After one pass through the creep feed grinder  51 , the blank sheet  46  will have the first blade set  7 . Next, the blank sheet  46  is removed from the machine bed  52  and is rotated 120 degrees, and is re-secured to the machine bed  52 . The process described above is repeated, which adds the second blade set  8 .