Patent Abstract:
A method and device for burning a pattern in a surface of wood or other charrable material. The device generally comprises a ceramic body having a raised pattern defined on a surface thereof and means for locally heating the raised pattern to a temperature sufficient to burn a pattern in a surface of wood contacted by the ceramic body. While various heating means are possible, two noted heating means are an electrically-resistive wire or an electrical-conductive ceramic material embedded in the ceramic body in proximity to the raised pattern, both of which serve to locally heat the raised pattern when current from a suitable electric current source flows therethrough.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims the benefit of U.S. Provisional Application No. 60/314,445, filed Aug. 23, 2001.  
         BACKGROUND OF INVENTION 1. Field of the Invention  
         [0002]    The present invention generally relates to tools for creating decorative designs and patterns on surfaces. 2. Description of the Related Art  
           [0003]    Tools and equipment currently available for creating decorative designs and patterns on wood and other charrable materials include metal hand tools and laser generators that produce a burned (i.e., charred or singed) pattern in a near-surface region of the material. Hand tools are labor-intensive, especially if a large surface is to be treated. For large surfaces or when a continuous or repetitive pattern is to be accurately reproduced, a laser is generally required. However, laser equipment is not readily affordable and often impractical for the general public. In addition, laser equipment cannot be easily transported, limiting use of the equipment to a studio or other permanent location.  
         SUMMARY OF INVENTION  
         [0004]    The present invention provides a method and device for burning a pattern in a surface of wood or other charrable material. The device generally comprises a ceramic body having a raised pattern defined on a surface thereof and means for locally heating the raised pattern, preferably to a temperature higher than portions of the ceramic body away from the raised pattern. The heating means is such that the raised portion is sufficiently heated to burn a pattern in a surface of wood contacted by the ceramic body. While various heating means are possible, two notable heating means are electrically-resistive wire or an electrical-conductive ceramic material embedded in the ceramic body in proximity to the raised pattern. Both of these heating means serve to locally heat the raised pattern when current from a suitable electric current source flows therethrough.  
           [0005]    With the device described above, a method of burning a pattern in a surface of wood generally comprises passing an electrical current through the ceramic body to heat the raised pattern to a temperature sufficient to burn wood, and then contacting the surface of the wood with the ceramic body to burn the pattern in the surface of the wood. Because the heating means is in proximity to the raised portion, the temperature of the raised pattern is higher than portions of the ceramic body away from the raised pattern, such that the pattern defined by the raised pattern is accurately transferred to the wood surface.  
           [0006]    In view of the above, it can be seen that a significant advantage of this invention is that patterns can be accurately reproduced, including continuous and repetitive patterns, in a wood surface (or surface of another charrable material) without the use of a laser. The device of this invention is more affordable and transportable than laser equipment, enabling the device to be widely used by the general public. As a result, the device and method of this invention can be practiced as a hobby, craft or business by a very large segment of the population to enhance the decorative appearance and value of a wide variety of goods.  
           [0007]    Other objects and advantages of this invention will be better appreciated from the following detailed description. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]    [0008]FIGS. 1 through 9 show ceramic wood-burning tools in accordance with various embodiments of this invention. 
     
    
     DETAILED DESCRIPTION  
       [0009]    Ceramic wood-burning tools in accordance with this invention are represented in FIGS. 1 through 9, with each being capable of transferring a pattern on the tool to the surface of wood or other material by burning (i.e., char or singe) the near-surface region of the material. The invention is particularly directed toward creating decorative burn patterns in the surface of wood, though various other materials could be treated with the tools of this invention to obtain desirable results. Therefore, though discussed in particular reference to wood, the invention is to be understood to apply to any material in which a pattern can be transferred to its surface by intense localized heating.  
         [0010]    Each of the tools shown in FIGS. 1 through 9 comprises a connector or holder supporting a ceramic body on whose exterior surface a raised pattern has been defined. The ceramic body is formed of any suitable ceramic material, such as porcelain and structural clays, the latter of which includes terra cotta and a material commercially available from Eberhard Faber under the name EFAPLAST, composed of clay, binder and hardening materials. Embedded in the ceramic body in close proximity to the raised pattern is a thermal member capable of sufficiently raising the temperature of the raised pattern so that contacting a wood surface with the ceramic body causes the decorative pattern defined by the raised pattern to be transferred to the wood surface. One such thermal member is an electrically-resistive wire, which includes but is not limited to nickel-chromium and nickel-chromium-iron alloys known in the art, a commercial example of which is known as Nichrome. Another such thermal member is an electrically-conductive ceramic material, such as a ceramic material in which metal particles are dispersed. Electrically-conductive ceramic materials that are commercially available include those referred to as thermal ceramics.  
         [0011]    In each case, the thermal member is preferably placed in the ceramic body after the body has been shaped but prior to firing, i.e., while the ceramic body is still in a green state. In addition, the raised pattern can be created in the ceramic body (such as by molding, sculpting, rolling, shaving, etc.) prior to or after embedding the thermal member. Firing the ceramic body serves to harden the ceramic material in which the thermal member is embedded, without damaging the thermal member. Electrical connection to the thermal member is provided, either by exposing opposite ends of the electrically-resistive wire, or otherwise contacting the ceramic body so that electric current will pass through the electrically-conductive ceramic material. Any suitable current source may be used.  
         [0012]    Transferring the decorative pattern defined by the raised pattern of the ceramic body to the desired wood surface will depend in part on the form of the ceramic body. The ceramic body can have various forms, some of which are represented in FIGS. 1 through 9. In each case, the thermal member preferably raises the temperature of the ceramic body locally at the raised pattern, as opposed to the bulk of the ceramic body. After contacting the wood surface in which the decorative pattern is desired, pressure is applied with the ceramic body to transfer of the pattern to the wood surface occurs over a period of time that will depend in part on the temperature of the raised pattern.  
         [0013]    In FIG. 1, a tip tool  10  is shown in which the ceramic body comprises a tip  12  (which defines the “raised pattern” discussed above). The tip  12  is mounted in a holder  14  that preferably can withstand the firing temperatures required for the ceramic material used to form the tip  12 . For example, the ceramic material and thermal member (electrically-resistive wire or electrically-conductive ceramic) can be packed into the holder  14  and the ceramic material shaped to define the tip  12 , after which the tip  12  is fired. In this manner, the tip  12  and holder  14  can be viewed as together forming the ceramic body discussed above. Alternatively, the thermal member can define the entire tip  12  if an electrically-conductive ceramic is used, in which case the tip  12  and holder  14  may be formed and fired separately, and then assembled such as by screwing the tip  12  into the holder  14 . The holder  14  is mounted to a connector  16 , through which a cable  18  passes for delivering the required electric current to the thermal member. FIG. 2 is similar to FIG. 1, and shows a carver  20  equipped with a ceramic bit (raised pattern)  22  that can be rotated with a motor  24  housed within the connector  26 . The carver  20  is useful for creating fill-in work, such as trees, grass, etc., in a decorative pattern.  
         [0014]    [0014]FIG. 3 shows a design end  30  having a flat surface  32  in which the raised pattern (not shown) is defined. Similar to the embodiments of FIGS. 1 and 2, the design end  30  is mounted to a connector  36  through which a cable  38  passes for delivering electric current to the thermal member (electrically-resistive wire or electrically-conductive ceramic), which may be embedded in the design end  30  near the surface  32 , or define the entire surface  32  if an electrically-conductive ceramic is used.  
         [0015]    [0015]FIG. 4 shows a roller  40  having a cylindrical surface  42  in which a raised pattern (not shown) is defined. A suitable material for the roller  40  is a kiln brick. The roller  40  is shown as being mounted to a connector  46  with an axle  44 . Electrical connection to the thermal member (electrically-resistive wire or electrically-conductive ceramic) embedded in the roller  40  is through a conductive path that includes a cable  48  within the connector  46  and a dynamic connection (not shown), such as carbon contacts, which enable current to be delivered to the roller  40  while the roller  40  is rotating. The roller  40  is particularly suitable for creating continuous or repetitive designs desired on long surfaces, such as panels, trim, drawer fronts, doors, etc.  
         [0016]    [0016]FIG. 5 shows a design plate  50  having a flat surface  52  that, similar to the tool of FIG. 3, has a raised pattern (not shown) defined thereon. The plate  50  differs in its purpose for larger designs, and makes use of a holder  54  with a lip  56  for supporting and gripping a recessed edge  58  of the plate  50 , such as with screws  57 . Electrical connection to the thermal member (electrically-resistive wire or electrically-conductive ceramic) embedded in the plate  50  is through complementary connections on the holder  54  and plate  50 . FIG. 6 shows a design plate  60  that makes use of a holder  64  that supports and grips the plate  60  in the same or similar manner as shown in FIG. 5. However, the holder  64  has telescoping portions  66  and a telescoping handle assembly  68  to enable the holder  64  to adjust in size to plates of different lengths or widths.  
         [0017]    [0017]FIG. 7 shows a contoured plate  70  that differs from the design plate  70  of FIG. 5 by having a curved surface  72  in which a raised pattern (not shown) is defined for creating a decorative pattern on a curved surface or corner. The plate  70  makes use of a holder  74  that supports and grips the plate  70  in the same or similar manner as shown in FIG. 5. However, the holder  74  is hinged to adjust for plates of different contours. The holder  74  has a support assembly  76  with telescoping curved arms  78  for adjustment of the holder  74 , with one of the arms  78  shown being mounted to a handle  79 . As before, electrical connection to the thermal member (electrically-resistive wire or electrically-conductive ceramic) embedded in the plate  70  is through complementary connections on the holder  74  and plate  70 .  
         [0018]    [0018]FIG. 8 shows a wood-burning tool adapted for a related but different use than those of the preceding embodiments, namely, burning a mortise  89  into a door or door jamb  88  for receiving a door hinge. For this purpose, the tool makes use of a ceramic body in the form of a plate  80 , and is equipped with an adjustable clamp  84  for gripping opposite surfaces of the door/jamb  88 , as well as a press  86  mounted to the clamp  84  for applying pressure through the plate  80  to the area of the door or jamb where the mortise is desired. The plate  80  is sized and shaped to duplicate that of the hinge to be mounted. The thermal member (electrically-resistive wire or electrically-conductive ceramic) is embedded in the plate  80 , and preferably is uniformly present over the entire surface  82  of the plate  80 , such that the surface  82  is effectively the raised pattern that will define the mortise  89 . Because of the increased amount of smoke and ash that will be generated, this device may be used in combination with a fan or air filtering system.  
         [0019]    Finally, FIG. 9 represents an automated method of continuously transferring a decorative pattern to a surface. A piece of wood  96  is shown passing beneath a roller  90  mounted on an axle  94 . The roller  90  has a cylindrical surface  92  in which a raised pattern (not shown) is defined. As with the roller of FIG. 4, the thermal member (electrically-resistive wire or electrically-conductive ceramic) is embedded in the roller  90  near its cylindrical surface  92 . Depending on the size of the roller  90 , the thermal member may be limited to a layer deposited or otherwise formed on the surface of the roller  90 . Electrical connection to the thermal member is through a conductive path that includes a dynamic connection (not shown), such as carbon contacts, which enables current to be delivered from the axle  94  to the roller  90  while the roller  90  is rotating. Finally, a drive roller  98  is shown as causing the wood  96  to move beneath the roller  90  at a speed synchronized with the roller speed. In this manner, the roller  90  can be used to accurately form continuous or repetitive designs on long surfaces, such as boards, doors, drawer fronts, trim, valances, shelves, counter top edges, etc.  
         [0020]    With each of the above embodiments, one can make designs, inlays or tips to accurately reproduce a decorative pattern, including continuous and repetitive patterns, on a wide variety of structures. The tools are all practical for use by individuals and small and home-based businesses in view of their relatively low cost and transportability.  
         [0021]    While the invention has been described in terms of a preferred embodiment, it is apparent that other forms could be adopted by one skilled in the art. Therefore, the scope of the invention is to be limited only by the following claims.

Technology Classification (CPC): 1