Abstract:
A cutting mat includes a flat, planar sheet of rigid but flexible material with a plastic film affixed to the lower surface and extending across the length and width of the sheet. In the preferred embodiment, the mat is formed of spring steel. A holder for the mat is formed of a planar sheet of plastic material with flaps formed in the holder to removably retain the cutting mat in position on the holder.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
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   STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
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   INCORPORATION-BY-REFERENCE OF MATERIAL Submitted on a Compact Disc 
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   BACKGROUND OF THE INVENTION 
   (1) Field of the Invention 
   The present invention relates generally to portable die cutting apparatus, and more particularly to an improved cutting mat for die cutters. 
   (2) Description of Related Art including information disclosed under 37 CFR 1.97, 1.98 
   Die cutting apparatus have long been used for cutting shapes and patterns from continuous sheet stock material. Rotary die cutting machines are typically expensive pieces of equipment, and are also expensive to operate, and are therefore unsuitable for smaller tasks. 
   In order to fulfill a need by educational institutions and the home consumer, a variety of smaller, portable roller die cutting machines have been developed. One such machine is disclosed in U.S. Pat. No. 5,647,260 to Stephen Nabity. This smaller, more economical device provides the necessary tools for cutting small shapes and designs, which may be used by the home craft industry as well as educational institutions. 
   A relatively new design of portable roller cutting die apparatus is that shown in pending patent application Ser. No. 29/227,314 entitled “Portable Die Cutter” and owned by the same owner of the present application. This portable device includes a pair of rollers mounted in spaced-apart parallel relationship and interconnected by gears to rotate simultaneously in opposing directions. The rollers are operably mounted within a lightweight housing, such that the entire device is lifted and operated with one hand of a consumer. A pair of wheels on the housing are rotated by pushing the housing along the surface of a table or the like, thereby rotating the rollers. A die assembly is fed between the rollers in a conventional fashion in order to cut stock positioned in the die assembly. 
   While the portable die cutter described above works well, there are aspects that it is desirable to address in order to improve the overall operation and ease of use of the device. For example, it is typical for the consumer to run the die assembly through the device 2 or 3 times to insure a clean continuous cut of the stock material. While this is not difficult to accomplish, it is undesirable to find that the apparatus was not operated a sufficient number of times to produce a clean cut. The partially cut stock is typically discarded, and the process started again. This can become frustrating if it occurs more than once during a session. 
   In addition to the frustration of a partially cut item, the increased number of times that the device is operated also reduces the life of the cutting mats and dies used in the machine. Thus, the efficiency of the machine is reduced proportional to the extra number of times that the machine must be operated to complete a cut. 
   The die assembly of prior art portable die cutters typically includes a base platform with a solid smooth upper surface. A cutting die is positioned on top of the platform with the die cutting edges projecting upwardly. The desired stock is placed on top of the die, and then a cutting mat is positioned over the top of the stock. This entire assembly is then fed between the rollers of the die cutter, which squeezes the assembly to cause the die to cut through the stock, against the cutting mat. The blade of the die cuts slightly into the cutting mat—thereby protecting the roller from being cut. The typical cutting mat is a sheet of plastic material, which must be replaced frequently during the die-cutting process, since the mat is partially cut during each operation of the device. 
   While plastic cutting mats work sufficiently, it is preferable to provide cutting mats of a more lasting material, such as spring steel. However, a drawback to the use of spring steel is that the mat is quite thin, and the edges of the mat can injure the user if not handled carefully. Thus, it is desirable to provide a holder for the cutting mat, which protects the users fingers from the edges of the mat. 
   Another drawback to spring steel cutting mats is the fact that the spring steel is not as compressible as the plastic material of plastic cutting mats. Thus, while the steel mats last longer, they can require additional runs through the die cutter to complete a cut. 
   BRIEF SUMMARY OF THE INVENTION 
   It is therefore a general object of the present invention to provide an improved cutting mat for a portable die cutter. 
   A further object is to provide a metal cutting mat with a holder to protect the user&#39;s fingers from the edges of the mat. 
   Yet another object of the present invention is to provide a cutting mat with a compressible sheet of material to enhance the cutting operation of the die cutter. 
   These and other objects will be apparent to those skilled in the art. 
   The cutting mat of the present invention includes a flat, planar sheet of rigid but flexible material with a plastic film affixed to the lower surface and extending across the length and width of the sheet. In the preferred embodiment, the mat is formed of spring steel. A holder for the mat is provided, formed of a planar sheet of plastic material with flaps formed in the holder to removably retain the cutting mat in position on the holder. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The preferred embodiment of the invention is illustrated in the accompanying drawings, in which similar or corresponding parts are identified with the same reference numeral throughout the several views, and in which: 
       FIG. 1  is a perspective view of a portable die cutter in which the cutting mat of the present invention may be used; 
       FIG. 2  is a schematic side view of a die assembly with the cutting mat of the present invention incorporated therein, and positioned in a roller die cutter of  FIG. 1 ; 
       FIG. 3  is an enlarged sectional view of a portion of a mat holder with the cutting mat retained thereon; and 
       FIG. 4  is a plan view of the mat holder of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, and more particularly to  FIG. 1 , a portable die cutter  12  is shown. While there are several varieties of portable die cutters available on the market, the cutting mat  10  of the present invention is designed specifically for use with a die cutter  12  of the type having opposing rotatable rollers  14 , as shown in  FIG. 2 . 
   Die cutter  12  includes a horizontally disposed slot  16  formed therethrough, through which die assembly  18  is directed. Die assembly  18  is drawn between rollers  14  to squeeze the die assembly  18  and cause a die to cut a pattern in a piece of stock material, as described in more detail hereinbelow. Die assembly  18  includes an elongated, planar platform  20  of substantially rigid material, such as a high-density plastic. Platform  20  has a flat upper and lower surfaces  20   a  and  20   b , respectively. However, the upper surface  20   a  is preferably tapered down to a smaller thickness  20   c  at each end of the platform. These tapered ends  20   c  assist in directing the assembly  18  between rollers  14  without disturbing the position of the die, stock and cutting mat of the die assembly  18 . 
   It should be noted that the sheet of stock material  24  and the two layers of cutting mat  10  are shown with their rearward edges lifted and curled upwardly away from the die  22  and platform  20 , in order to more clearly identify each of these components. In actual use, die assembly  18  would lay substantially flat, in a sandwich of layers. 
   A desired die  22  is positioned generally centrally on the top surface  20   a  of platform  20 . Die  22  typically includes a flat metal base portion  22   a  with an upwardly projecting blade portion  22   b . Blade portion  22   b  may be formed in any of a wide variety of shapes and sizes, to form cuts of desired characteristics in stock material  24 . Blade portion  22   b  is also preferably metal. 
   Cutting mat  10  of the present invention is formed of two layers of material: a high-density planar sheet  10   a  with a with a plastic film  10   b  permanently mounted on a the lower cutting surface of the sheet  10   a . Preferably, sheet  10   a  is a rectangular piece of 0.007-inch spring steel, such as 1095 tempered steel. The edges of sheet  10   a  should be burr free, to decrease the chance of injury to a user. Sheet  10   a  has a length and width greater than that of the die  22  as well as stock material  24 , to form an upper backing plate in die assembly  18 . Film  10   b  is about 0.002 inches in thickness, and has a permanent adhesive backing, so as to affix the film to the cutting surface of sheet  10   a  to form an integral unit. 
   It has been found that the addition of a layer of film  10   b  to the standard cutting mat  10   a  serves two beneficial purposes. First, the film adds a layer of thickness, which causes an increase of pressure when die assembly  18  is run between rollers  14  of die cutter  12 . This is turn increases the cutting distance of the die  22 , and increases the chances of a complete and clean cut with fewer runs through the rollers  14 . When using film layer  10   b , the cutter will create a clean complete cut in 1-3 runs through the die cutter, whereas without the film, it typically required additional runs, and sometimes a complete and clean cut simply would not occur. 
   The second benefit of the film layer  10   b  is the additional layer of protection for cutting mat sheet  10   a . Thus, film  10   b  acts as a type of “wear plate” for mat  10   a , thereby increasing the effective life of the cutting mat  10 . 
   One undesirable characteristic of spring steel as a material for cutting mat  10  is the sharpness of the edges of the mat. While not typically a problem, the fact that the material has a very small thickness increases the opportunity of a cut or injury when handling the cutting mat  10 . The inventor herein has devised a holder  26 , which will safely retain cutting mat  10  in position, without requiring the user to touch the mat  10  after installation in the holder. 26 , as shown in  FIGS. 3 and 4 . 
   Referring now to  FIG. 4 , holder  26  is shown with a cutting mat  10  in broken lines, to show the retained position of the mat  10 . Holder  26  is preferably formed of a plastic material such as clear PETG or its equivalent with a thickness of about 0.015 inches. While there are a variety of ways in which holder  26  can retain mat  10  in position, it has been found that the use of four semi-circular flaps  28  is a simple and efficient manner of accomplishing this task. While other shapes would work, the semi-circular shape was chosen for its omission of sharp points. 
   Each flap  28  is formed by cutting a semi-circle  30  through the thickness of holder sheet  26 , with the two termini  32  of each semi-circle directed towards the end edges of the holder sheet. Two flaps  28  are aligned both longitudinally and transversely on holder  26 , and positioned apart a distance to retain cutting mat  10  therebetween. 
     FIG. 3  shows one flap  28  of holder  26  pushed downwardly to retain an edge of cutting mat  10  between the flap  28  and holder  26 . 
   Whereas the invention has been shown and described in connection with the preferred embodiments thereof, many modifications, substitutions and additions may be made which are within the intended broad scope of the appended claims. For example, the lengths, widths and thicknesses of the described embodiments are simply given as examples of versions of the invention that work for a particular die cutter. Other thicknesses and dimensions would work with this die cutter, and other similar die cutters. Similarly, the listed materials could be different than those specified, and remain within the spirit and scope of the invention.