Abstract:
A method for manufacturing a metallic artificial nail for attachment to a natural nail includes the step of heat-stamping a metallic substrate having a heat-activatable layer to a surface of a contoured nail body whereby the metallic substrate is bonded to the nail body. Also provided is a die set for heat-stamping a metallic substrate onto a contoured nail body to form a metallic artificial nail which includes a die including a first contoured surface substantially corresponding to the contour of a bottom surface of the nail body for supporting the nail body in the die set and a punch including a second contoured surface positioned opposite the first contoured surface. The second contoured surface substantially corresponds to the contour of a top surface of the nail body for conforming the metallic substrate to the contour of the top surface of the nail body during heat-stamping.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to artificial nails that are applied to natural nails with an adhesive, and more particularly to an artificial nail having a heat-stamped outer metallic layer and its method of manufacture.  
           [0002]    Artificial nails have been used for many years to enhance the cosmetic appearance of the fingers. Some individuals opt to use artificial nails because their own nails are too weak to grow to a desirable length without breaking. Others choose artificial nails because they are considerably stronger and more durable than natural nails, and because nail polish adheres better to the artificial nail surface. Some individuals are unhappy with the shape and contour of their natural nail and opt to use an artificial nail to improve the appearance of their nails.  
           [0003]    It has been known in the art of adorning the hands to provide ornamental fingernail accessories made from thin, molded plastic members manufactured generally in the shape of a fingernail. Indeed, numerous artificial fingernail manufacturers have provided a variety of combinations of materials, arrangements, and colors in fingernail accessories. With the advent of such artificial fingernail accessories, the wearer could now have intricately pre-designed fingernails that are simply attached to the natural fingernail and then later easily removed.  
           [0004]    Conventional pre-designed fingernails include a decorative design stenciled or air-brushed on a top surface thereof. The pre-designed artificial nail is glued to the surface of the natural nail by applying an amount of a liquid bonding adhesive to the bottom surface of the artificial nail and/or the top surface of the natural nail to affix the accessory to the nail. Usually the wearer must wipe or trim away any excess adhesive and then wait several moments until the adhesive dries to ensure that the accessory is secured to the nail. An overlay is then typically applied to the entire top surface of the artificial nail. The overlay is usually transparent or translucent so that the decorative design is visible on the top surface of the artificial nail. Once the overlay sets, the artificial nail is shaped as desired.  
           [0005]    Of the myriad possible designs given to artificial nails, a particularly attractive ornamentation is to provide the artificial nail with a metallic look, whereby the nail appears to be made from a metallic material. Typically, this ornamentation is provided by painting or otherwise applying a polish having a metallic appearance directly on an artificial nail. This may be done by the consumer or it may be pre-applied prior to sale to the consumer. In either event, this procedure can be expensive, messy and time consuming. Additionally, nail polish typically chips and peels, eventually requiring reapplication whether on natural or artificial nails.  
           [0006]    It is known from U.S. Pat. No. 6,296,836 to provide a nail with a metallic leafing material layer adhered to the nail to achieve the metallic look. However, this ornamentation is accomplished by first applying an adhesive coating to the top surface of the nail with a brush, adhering a thin sheet of metallic material having an area larger than the nail over the adhesive coating, smoothing the material with a brush to eliminate creases and wrinkles and trimming the excess material that extends beyond the periphery of the nail. Finally, a coating of clear polish or other sealer is applied over the sheet material to maintain the decorated nail&#39;s durability. While the desired ornamentation is achieved, the process is again messy and time consuming and requires an amount of skill to achieve satisfactory results.  
           [0007]    Accordingly, it is an object of the present invention to provide an ornamental artificial nail having a pre-applied decorative metallic appearance which is simply and inexpensively manufactured.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention is a method and a die set for manufacturing a metallic artificial nail for attachment to a natural nail. “Artificial nail”, as used herein also includes fingernail extensions, referred to in the trade as “tips”, which will be more fully explained hereinbelow.  
           [0009]    The method includes the step of heat-stamping a metallic substrate having a heat-activatable layer to a surface of a contoured nail body whereby the metallic substrate is bonded to the nail body. Preferably, the step of heat-stamping includes the steps of placing the nail body in a heat-stamping press die set, placing the metallic substrate in the die set such that the heat-activatable layer faces the top surface of the nail body, closing the die set so that the heat-activatable layer makes contact with the top surface of the nail body and heating the die set to cause the heat-activatable layer to bond to the top surface of the nail body. The method further preferably includes the step of coating the metallic substrate with a clear sealant.  
           [0010]    In the preferred embodiment of the present invention, the heat-stamping press die set includes a first contoured surface substantially corresponding to the contour of the bottom surface of the nail body for supporting the bottom surface of the nail body when the die set is closed. Similarly, the heat-stamping press die set preferably includes a second contoured surface substantially corresponding to the contour of the top surface of the nail body. The second contoured surface of the die set faces the top surface of the nail body when the die set is closed. A cutting edge surrounding the second contoured surface may be provided for cutting the metallic substrate around the periphery of the nail body as the die set is closed.  
           [0011]    As the die set is closed, the second contoured surface of the die set bears against the metallic substrate causing the substrate to stretch and conform to the top surface of the nail body. Additionally, the peripheral edges of the cut metallic substrate adhere to the peripheral edge of the nail body and become beveled during cutting.  
           [0012]    The metallic substrate is preferably made from a metal selected form the group consisting of aluminum, silver, copper and gold. It may be placed over the entire top surface of the nail body or it may be placed over only a portion of the top surface of the nail body.  
           [0013]    Preferably, the nail body is a one-piece injection molded body made from a transparent material. The metallic nail may be a full cover, wherein the proximal end of the nail body is sized and shaped to substantially correspond to the full nail bed of the natural nail, or the nail may be a nail tip, wherein the proximal end of the nail body is sized and shaped to be attachable to only the distal end of the natural nail.  
           [0014]    The method for manufacturing a metallic artificial nail according to the present invention preferably includes the step of stretching the metallic substrate over the contoured nail body prior to heat-stamping. In particular, a nail body is placed in the heat-stamping press die set and a metallic substrate is positioned over the nail body such that the heat-activatable layer of the substrate faces the top surface of the nail body. The metallic substrate is engaged on opposite sides of the nail body with stretching rollers, which press the metallic substrate onto the nail body to stretch the metallic substrate over the contoured nail body prior to heat-stamping.  
           [0015]    A die set for heat-stamping a metallic substrate onto a contoured nail body to form a metallic artificial nail is also provided as a result of the present invention. The die set generally includes a die including a first contoured surface substantially corresponding to the contour of a bottom surface of the nail body for supporting the nail body in the die set and a punch including a second contoured surface positioned opposite the first contoured surface. The second contoured surface substantially corresponds to the contour of a top surface of the nail body for conforming the metallic substrate to the contour of the top surface of the nail body during heat-stamping.  
           [0016]    The punch is preferably provided on a top die shoe and may further include a cutting edge surrounding the second contoured surface for cutting the metallic substrate around the periphery of the nail body during heat-stamping. The die is preferably provided on a bottom die shoe which faces the first die shoe. The die set further preferably includes stretching rollers positioned on opposite sides of the punch for stretching the metallic substrate onto the contoured nail body prior to heat-stamping.  
           [0017]    As a result of the present invention, an artificial nail having a decorative metallic appearance is provided. The method for manufacturing the nail is simple, cost effective and does not require the messy separate application of adhesive or the smoothing or trimming of the metallic sheet material. The result is an inexpensive cosmetically appealing artificial nail having a pre-applied metallic appearance.  
           [0018]    Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a perspective view of the metallic artificial nail formed in accordance with the present invention.  
         [0020]    [0020]FIG. 2 is a cross-sectional view of the nail shown in FIG. 1 taken along the line  2 - 2 .  
         [0021]    [0021]FIG. 3 is a cross-sectional view of a die set used for forming the metallic artificial nail in accordance with the present invention in its open position.  
         [0022]    [0022]FIG. 4 is a cross-sectional view of the die set shown in FIG. 3 in its closed position.  
         [0023]    [0023]FIG. 5 is a cross-sectional view of the preferred embodiment of a die set used for forming the metallic artificial nail in accordance with the present invention in its open position.  
         [0024]    [0024]FIG. 6 is a cross-sectional view of the die set shown in FIG. 5 in its intermediate position.  
         [0025]    [0025]FIG. 7 is a cross-sectional view of the die set shown in FIGS. 5 and 6 in its closed position.  
         [0026]    [0026]FIG. 8 is a cross-sectional view of the die set shown in FIGS.  5 - 7  returned to its open position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]    Referring first to FIGS. 1 and 2, a metallic artificial nail  8  formed in accordance with the present invention is shown. The metallic artificial nail  8  preferably includes a one-piece molded body  10  having a distal end  11 , a proximal end  12 , a top surface  13  and a bottom surface  14 . The proximal end  12  and, more particularly, the bottom surface  14  adjacent the proximal end  12  is sized and shaped to be attachable to the top surface of a natural nail. Preferably, the distal end  11  is sized to extend beyond the end of the natural nail when the artificial nail is attached to the natural nail.  
         [0028]    The nail body  10  is preferably injection molded from a plastic material such as ABS plastic, and is generally rectangular in shape. The plastic material can be transparent or opaque. The distal end  11  can be rounded as shown in FIG. 1 or it can be straight. The artificial nail is not limited to any particular dimensions. In other words, the artificial nail of the present invention is useful for fingernails and/or toenails and can be made in a variety of sizes and shapes. For instance, the proximal end  12  of the nail body  10  may substantially correspond in size and shape to the full nail bed of a natural fingernail, whereby the artificial nail is termed a full nail cover that is applied over the full nail bed of a natural fingernail. Alternatively, the proximal end  12  may be attachable to only the distal end of a natural fingernail, that is, for example, it may correspond in size and shape to only the distal end of the natural nail bed, whereby the artificial nail is termed a nail tip  17  that is applied to the end of the natural fingernail.  
         [0029]    Bonded to the top surface  13  of the nail body  10  is a metallic substrate  15 . As will be discussed in further detail below, the metallic substrate  15  is a thin sheet of metallic material  15  having a heat-activatable layer  16  for permanently bonding the metallic material to the nail body  10 . The thin sheet of metallic material can be aluminum, silver, copper, gold or other metallic leafing material and the heat activatable layer  16  can be a heat-activated adhesive. Such material is supplied by Admiral Coated Products under part numbers such as ALUM-W718D or GOLD-W127Y. Upon its application to the nail body  10 , the metallic substrate  15  creates a smooth shiny appearance that additionally adds strength to the nail and does not crack or chip easily. As shown in FIG. 1, the metallic substrate  15  is applied over the entire top surface  13  of the nail body  10 . However, it may be applied over only a portion thereof, as desired. Additionally, one or more coatings of a clear polish  17  or other sealer may be applied over the metallic substrate  15  to maintain the decorated nail&#39;s durability.  
         [0030]    Referring now to FIGS. 3 and 4, the metallic artificial nail is formed according to the present invention in a heat-stamping press having a die set  18  configured to permanently bond the metallic substrate  15  to the nail body. The die set  18  includes a top die shoe  20  having a punch  22  and a bottom die shoe  24  having a die  26 . In the preferred embodiment, the punch  22  includes a contoured surface  28  that corresponds to both the longitudinal and lateral contour of the top surface  13  of the nail body  10 . Similarly, the die  26  preferably includes a contoured surface  30  that corresponds to both the longitudinal and lateral contour of the bottom surface  14  of the nail body  10 . The contoured surface  28  of the punch  22  can be bounded by a cutting edge  32 , which, as will be discussed in further detail below, trims the excess material of the thin metallic substrate  15  that extends beyond the periphery of the nail body  10 . Preferably, the cutting edge  32  closely corresponds to the periphery of the nail body  10 .  
         [0031]    The die set  18  is arranged so that the contoured surface  28  of the punch  22  is aligned and mates with the contoured surface  30  of the die  26  when the heat-stamping press is closed as shown in FIG. 4. Only one die set  18  is shown in FIGS. 3 and 4, however, as will be discussed in further detail below, an arrangement of multiple die sets can be used in the heat-stamping press for simultaneously forming a plurality of metallic artificial nails. Additionally, the means for heating the die set  18  is not shown in FIGS. 3 and 4, however, as is typical in heat-stamping presses of this type, the top and bottom die shoes  20  and  24 , include heating elements which raise the temperature of the die set, typically to about 500° F.  
         [0032]    In operation, a nail body  10  is first positioned on the contoured surface  30  of the die  26 . The metallic substrate  15  is positioned on top of the nail body  10  so that the heat-activatable layer  16  faces the top surface  13  of the nail body. The heated top and bottom die shoes  20  and  24  are then brought together so that the contoured surface  28  of the top die shoe punch  22  bears upon the metallic substrate  15  and causes it to stretch as it conforms to the contoured surface. This stretching results in a smooth wrinkle-free appearance to the final product. Since the die set  18  is heated, the heat-activatable layer  16  reacts to the heat and bonds to the top surface  13  of the nail body as the press closes further. Upon closure of the die set  18 , the cutting edge  32  cuts the metallic substrate  15  around the periphery of the nail body  10 . As the metallic substrate  15  is cut, the heat-activatable layer  16  causes the peripheral edges of the metallic substrate to adhere to the peripheral edge of the nail body  10 . In other words, the peripheral edge of the metallic substrate  15  will be beveled as a result of being heat-cut by the cutting edge  32 . The manufacturing process is completed by opening the die set  18  and removing the completed metallic artificial nail  8  from the press. As mentioned above, the nail  8  can further be coated with a clear sealant to provide added durability.  
         [0033]    Referring now to FIGS.  5 - 8 , a preferred form of a die set  34  is shown. The die set  34  shown in FIGS.  5 - 8  includes a plurality of punches  36  on the top die shoe  38  and a plurality of mating dies  40  on the bottom die shoe  42 . Three punches  36  with three respective dies  40  are shown in FIGS.  5 - 8 , however, a total of ten punches and dies is preferred to simultaneously heat-stamp a fall set of ten metallic artificial nails corresponding in size to each finger of both hands. The die set  34  shown in FIGS.  5 - 8  further preferably includes stretching rollers  44  positioned on both sides of each of the punches  36  and dies  40 . The stretching rollers  44  are cylindrical rods having a length at least as long as the nail bodies  10  and a curved peripheral surface to prevent damage to the metallic substrate  46 . The stretching rollers  44  can be mechanically connected to the top die shoe  38 , but are designed to move vertically independent of the top die shoe. As will be discussed below, the purpose of the stretching rollers  44  is to initially pre-stretch the metallic substrate  46  over the contour of the nail body  10  prior to actual heat-stamping.  
         [0034]    The preferred die set  34  shown in FIGS.  5 - 8  further includes a metallic substrate feed system having a feed spool  48  and a waste spool  50 . Unlike the metallic substrate  15  described above, the metallic substrate  46  used with the preferred die set  34  shown in FIGS.  5 - 8  is releasably carried on a backing layer  52  disposed opposite the heat-activatable layer  54 . The feed spool  48  supports the metallic substrate  46  in roll form and continuously supplies the substrate to the die set  34  such that the backing layer faces the punches  36  and the heat-activatable layer  54  faces the dies  40 . The metallic substrate  46  is incrementally fed through the die set  34  so that prior to each heat-stamping, there is metallic substrate material positioned above each nail body  10 .  
         [0035]    In operation, a nail body  10  is first positioned on the contoured surface of each die  40 . The metallic substrate feed system positions metallic substrate material  46  over each nail body  10  so that the heat-activatable layer  54  faces the top surface of the nail body, as shown in FIG. 5. With everything in place, the stretching rollers  44  simultaneously traverse downward toward the nail bodies  10  and engage the metallic substrate  46 . The stretching rollers  44  straddling each die  40  stretch the metallic substrate  46  over the contour of each nail body  10 , as shown in FIG. 6. The heated top die shoe  38  is then brought downward so that the contoured surface of the top die shoe punches  36  bears upon the metallic substrate  46  and the nail body  10 , as shown in FIG. 7. The heat-activatable layer  54  reacts to the heat supplied by the top die shoe  38  and bonds to the top surface of the nail body  10 . Only the area of the metallic substrate  46  directly in contact with the heated top die shoe punches  36  will react to the heat and will be released from the backing layer  52 . This leaves portions of the metallic substrate  46  between the heated punches intact on the backing layer  52 . It is noted that by supplying the metallic substrate  46  on a releasable backing layer  52  and heating only the portion of the substrate to be bonded to the nail body, the top die shoe punches  36  do not require cutting edges, as described above. In other words, it is not necessary to cut the metallic substrate  46  because only the heated area of the substrate will be released from the backing layer  52  and bonded to the nail body  10 .  
         [0036]    Once bonding is complete, the top die shoe  38  is raised and the completed metallic artificial nails are removed from the bottom dies  40 . New nail bodies  10  can then be placed on the bottom dies  40  and the metallic substrate feed system incrementally positions metallic substrate material above each nail body, as shown in FIG. 8. The process described above is repeated to produce another set of metallic artificial nails.  
         [0037]    As a result of the process of the present invention, a metallic artificial nail having a desirable appearance is provided. The process for manufacturing the nail is simple, cost effective and does not require the messy separate application of adhesive or the smoothing or trimming of the metallic sheet material. The pre-applied metallic layer is durable, chip resistant and cosmetically appealing.  
         [0038]    While there has been described what is presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that various changes and modifications may be made to the invention without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention.