Abstract:
A microwave grill for converting microwave energy to heat and applying the heat to a grillable food or other grillable substance. The microwave grill a cover and a base that each have a grill element and an enclosure. The grill element includes a microwave absorbent material and a grilling surface that are in thermal communication with each other. The enclosure is attached to the grill element. The enclosure is fabricated from a microwave transparent material possessing a low heat transfer rate. The first enclosure substantially extends over the first microwave absorbent material. A hinge mechanism operably attaches the cover and the base. An offset bump extends from at least one of the enclosures to maintain the cover and the base in a first spaced-apart configuration when the cover and the base are in a closed configuration.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from U.S. Provisional patent application Ser. No. 60/884,797 which was filed on Jan. 12, 2007, and which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention in general relates to appliances that operate by changing microwave energy to heat energy and conducting the heat to food by contact, and more particularly to such appliances that can be used to grill foods. 
       BACKGROUND OF THE INVENTION 
       [0003]    Appliances that heat grillable food or other grillable substances by causing microwave energy to be absorbed by an intermediate body, such as a block of ferrite, which in turn transfers heat to the grillable food, which we shall refer to herein as microwave grills, have been known for more than twenty years. 
         [0004]    These appliances inherently require no ventilation of burned fuels and thus can be used in a small kitchen, use a ready source of energy, and are very fast as compared to conventional grills. Yet a commercially successful microwave grill has never been produced. The reason is that prior art microwave grills have never reached the degree of reliability and ease of use expected for kitchen appliances, particularly in the upscale homes and businesses that would tend to use such grills. 
         [0005]    Freedman et al., U.S. Pat. No. 4,362,917, describe a block of ferrite binded to a microwave transparent cover. Teich et al., U.S. Pat. No. 4,454,403, describes a silicone material having ferrite material dispersed within the silicone binded to a microwave transparent cover. The ferrite material in these references continuously contacts the microwave transparent cover and transfers heat across the whole of the microwave transparent cover making the microwave transparent cover uncomfortable to the touch of a user. In addition, these designs do not include a suitable means for handling grease and other liquids that are generated in the grilling process. 
         [0006]    Levinson, U.S. Pat. No. 5,736,718, describes a vertical microwave grilling apparatus with a separate collection container. This arrangement requires alignment between the grilling apparatus and the collection container and is really too messy to appeal to the average upscale griller. 
         [0007]    Barnes, U.S. Pat. No. 6,608,292, discloses a microwave grill having a cover that is pivotally mounted to the base. The cover and base each include a grill element. After preheating, food is placed between the grill elements and the microwave grill is placed in a microwave oven to cook the food. 
       SUMMARY OF THE INVENTION 
       [0008]    The invention relates to an enhanced microwave grill that provides increased functionality to prior microwave grills such as is disclosed in Barnes, U.S. Pat. No. 6,608,292. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a microwave grill according to an embodiment of the invention where the microwave grill is in a closed configuration. 
           [0010]      FIG. 2  is a perspective view of the microwave grill in an opened configuration. 
           [0011]      FIG. 3  is a perspective view of a base and cover of the microwave grill in a separate position. 
           [0012]      FIG. 4  is a top view of the microwave grill. 
           [0013]      FIG. 5  is front view of the microwave grill. 
           [0014]      FIG. 6  is a side view of the microwave grill. 
           [0015]      FIG. 7  is a sectional view of the microwave grill taken along a line  7 - 7  in  FIG. 4 . 
           [0016]      FIG. 8  is a sectional view of the microwave grill taken along a line  8 - 8  in  FIG. 4 . 
           [0017]      FIG. 9  is a side view of an alternative configuration of a hinge mechanism for the microwave grill. 
           [0018]      FIG. 10  is a front perspective view of a grill spacer for use with the microwave grill. 
           [0019]      FIG. 11  is a back perspective view of the grill spacer. 
           [0020]      FIG. 12  is a perspective view of the grill spacer attached to a base handle on the microwave grill. 
           [0021]      FIG. 13  is a side view of the grill spacer attached to the handle on the microwave grill. 
           [0022]      FIG. 14  is a front view of another embodiment where the microwave grill has three grill elements. 
           [0023]      FIG. 15  is a front view of another embodiment where two microwave grills are stacked upon each other. 
           [0024]      FIG. 16  is a front view of another embodiment where a stand is used in conjunction with the microwave grill. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    A microwave grill according to an embodiment of the present invention is illustrated at  10  in the Figures. The microwave grill  10  enables foods to be prepared with a similar flavor and appearance that is obtained through cooking on a conventional outdoor grill. 
         [0026]    The microwave grill requires no electricity by itself to operate. Rather, the microwave grill  10  is used in conjunction with a microwave oven (not shown). The microwave grill is preferably dishwasher safe, meaning that the microwave grill may be washed in a dishwasher without degrading or damaging the components thereof. 
         [0027]    The microwave grill  10  generally includes a base  12  and a cover  14  that are pivotally mounted with respect to each other to provide a clam-shell configuration. This configuration permits the cover  14  to be positioned adjacent the base  12  (as illustrated in  FIG. 1 ) for cooking and then pivoted apart from each other (as illustrated in  FIG. 3 ) for placing foods onto and removing foods from the microwave grill. 
         [0028]    The base  12  generally includes a base enclosure  20  and a base grill element  22 , as most clearly illustrated in  FIG. 2 . The base enclosure  20  is preferably formed with base side handles  30 . 
         [0029]    The base side handles  30  may be formed from the same material as the rest of the base enclosure  20 . Alternatively, the base side handles  30  may be formed from a material that is different than the other portions of the base enclosure  20 . In this configuration, the base side handles  30  may be formed from a material having a heat transfer rate that is lower than the heat transfer rate of the other portions of the base enclosure  20 . This configuration further reduces the temperature of the side handles  30  to thereby enable the microwave grill  10  to be used without protecting the user&#39;s hands. 
         [0030]    The base grill element  22  absorbs microwave energy and converts the microwave energy into thermal energy to cook the food that is placed on the base grill element  22 . The base grill element  22  may have a variety of configurations such as being substantially flat or having a plurality of ribs  32  formed thereon. The ribs  32  not only provide a searing effect that is similar to conventional grilling but also assist in draining liquids that are released from the food during cooking. Alternatively, the base grill element  22  may have a substantially flat surface. 
         [0031]    The base grill element  22  preferably has a convex configuration such that a center area of the base grill element  22  is above an edge of the base grill element  22 , as most clearly illustrated in  FIGS. 7 and 8 . Forming the base grill element  22  with the convex configuration assists in draining liquids that are released from the food during the cooking process. 
         [0032]    The base grill element  22  may be fabricated from a variety of materials. One suitable material for fabricating the base grill element  22  is stamped aluminum. To reduce the potential of food sticking to the base grill element  22 , an outer surface of the base grill element  22  may be covered by a non-stick coating such as TEFLON. It is also possible to fabricate the base grill element  22  from anodized aluminum. 
         [0033]    The base grill element  22  includes a microwave absorbent material on a back surface thereof. The microwave absorbent material may be ferrite or non-ferrite based. The microwave absorbent material may include a ferrite mixture of resin and a metal oxide. A few suitable materials for use in the ferrite mixture are XYLOP and Powder Tech FP350. 
         [0034]    The base enclosure  20  may be fabricated from a microwave transparent material that does not absorb or reflect microwave energy during the cooking process. The material used for fabricating the base enclosure  20  also preferably possesses good insulating characteristics so that the base enclosure  20  resists heating when the microwave grill  10  is placed in a microwave oven. 
         [0035]    This characteristic thereby enables the microwave grill  10  to be lifted by a person without the use of an oven mitt or other protective device. One suitable material for fabricating the base enclosure  20  is a bulk molding compound with low microwave absorption rates. 
         [0036]    A base trough  34  may be located around the perimeter of the base grill element  22  to capture liquids that are released from the food during cooking. The width and depth of the base trough  34  are selected so that the base trough  34  has sufficient size to collect the liquids that are released so that the released liquids do not remain on the base grill element  22 . In one configuration, the base trough  34  has a capacity of about 50 milliliters. 
         [0037]    The base enclosure  20  preferably has a recess formed therein that is adapted to receive the base grill element  22 . The base grill element  22  is disposed in and supported by the base enclosure  20 . To reduce the heat transfer between the base enclosure  20  and the base grill element  22 , a void space is provided between the base enclosure  20  and the base grill element  22 . 
         [0038]    The base  12  may include a base water-tight seal that is located around the perimeter of the base grill element  22  to prevent liquids from going between the base enclosure  20  and the base grill element  22  not only during cooking but also during cleaning such as in a dishwasher. The base water-tight seal may be formed from a friction fit between the base enclosure  20  and the base grill element  22 . Alternatively, the base water-tight seal may be formed from a heat resistant adhesive material, such as epoxy glue. It is also possible to configure the base grill element  22  so that it can be removed from the base enclosure  20  for cleaning. 
         [0039]    The cover  14  generally includes a cover enclosure  40  and a cover grill element  42 . The cover enclosure  40  is preferably formed with cover side handles  50 . The cover enclosure  40  may also include a cover front handle  52 . 
         [0040]    The cover side handles  50  and the cover front handle  52  may be formed from the same material as the rest of the cover enclosure  40 . Alternatively, the cover side handles  50  and the cover front handle  52  may be formed from a material that is different than the other portions of the cover enclosure  40 . In this configuration, the cover side handles  50  and the cover front handle  52  may be formed from a material having a heat transfer rate that is lower than the heat transfer rate of the other portions of the cover enclosure  40 . 
         [0041]    The cover grill element  42  absorbs microwave energy and converts the microwave energy into thermal energy to cook the food that is placed on the cover grill element  42 . The cover grill element  42  may have a variety of configurations such as being substantially flat or having a plurality of ribs  54  formed thereon. The ribs  54  not only provide a searing effect that is similar to conventional grilling but also assist in draining liquids that are released from the food during cooking. Alternatively, the cover grill element  42  may have a substantially flat surface. 
         [0042]    The cover grill element  42  may be fabricated from a variety of material. One suitable material for fabricating the cover grill element  42  is stamped aluminum. To reduce the potential of food sticking to the cover grill element  42 , an outer surface of the cover grill element  42  may be covered by a non-stick coating such as TEFLON. It is also possible to fabricate the cover grill element  42  from anodized aluminum. 
         [0043]    The cover grill element  42  includes a microwave absorbent material on a back surface thereof. The microwave absorbent material may be ferrite or non-ferrite based. The microwave absorbent material may include a ferrite mixture of resin and a metal oxide. Suitable materials for use in the ferrite mixture are XYLOP and Powder Tech FP350. 
         [0044]    The cover enclosure  40  may be fabricated from a microwave transparent material that does not absorb or reflect microwave energy during the cooking process. The material used for fabricating the cover enclosure  40  also preferably possesses good insulating characteristics so that the cover enclosure  40  resists heating when the microwave grill  10  is placed in a microwave oven. This characteristic thereby enables a person to touch the outer surface of the cover enclosure  40  without injury. One suitable material for fabricating the cover enclosure  40  is a bulk molding compound with low microwave absorption rates. 
         [0045]    The cover enclosure  40  preferably has a recess formed therein that is adapted to receive the cover grill element  42 . The cover grill element  42  is disposed in and supported by the cover enclosure  40 . To reduce the heat transfer between the cover enclosure  40  and the cover grill element  42 , a void space is provided between the cover enclosure  40  and the cover grill element  42 . 
         [0046]    The base  12  may include a cover water-tight seal that is located around the perimeter of the cover grill element  42  to prevent liquids from going between the cover enclosure  40  and the cover grill element  42  not only during cooking but also during cleaning such as in a dishwasher. The cover water-tight seal may be formed from a friction fit between the cover enclosure  40  and the cover grill element  42 . Alternatively, the cover water-tight seal may be formed from a heat resistant adhesive material, such as epoxy glue. It is also possible to configure the cover grill element  42  so that it can be removed from the cover enclosure  40  for cleaning. 
         [0047]    A cover trough  56  may be located around the perimeter of the cover grill element  22  to capture liquids that are released from the food during cooking when the microwave grill  10  is used with the cover  14  in the open position. The width and depth of the cover trough  56  are selected so that the cover trough  56  has sufficient size to collect the liquids that are released so that the released liquids do not remain on the base grill element  22 . In many configurations, the cover trough  56  has a capacity of about 50 milliliters. 
         [0048]    At least one of the base enclosure  20  and the cover enclosure  40  includes at least one offset bumps  58  on a surface thereof. The offset bumps  58  maintain the upper surface of the base enclosure  20  a slight distance away from the lower surface of the cover enclosure  40  when the microwave grill  10  is closed. In one configuration, the offset bumps  58  have a thickness of less than 10 millimeters and preferably about 2 millimeters. The offset bumps  58  thereby reduce the potential of arcing between the base grill element  22  and the cover grill element  42 . 
         [0049]    The microwave grill  10  may include a hinge assembly  60  for interconnecting the base  12  and the cover  14 . The hinge assembly  60  preferably includes a pair of hinge mechanisms  62  that may be placed along a back edge of the microwave grill  10 . 
         [0050]    Each of the hinge mechanisms  62  may include a pin extending from the cover enclosure  40  and a slot formed in the base enclosure  20 . In a first configuration, which is illustrated in  FIG. 3 , the slot has a V-shaped configuration with a first leg  70  being closed and a second leg  72  being open. 
         [0051]    Using this configuration for the hinge mechanisms  62  enables the pins  64  and the slots  66  to be molded into the cover enclosure  40  and the base enclosure  42 , respectively, to which the component is associated. The hinge mechanism thereby is durable and allows the cover  14  to be positioned in a variety of orientations with respect to the base  12  as well as separated from the base  12 . 
         [0052]    The hinge mechanisms  62  also enable a spacing between the base  12  and the cover  14  to be adjusted depending on the thickness of the food being cooked so that both the base  12  and the cover  14  remain substantially aligned with the upper and lower surfaces of the food during cooking to enhance the efficiency of the cooking process. 
         [0053]    Alternatively, the slot  66  may include a third leg  74  that extends from the enclosed end of the first leg  70  towards the open end of the second leg  72 . The alternative slot configuration enables the cover  14  to slide forward with respect to the base  12 . When the cover  14  slides forward with respect to the base  12 , a ledge portion  76  adjacent the pin  64  on the cover enclosure  40  engages a lip  78  on the base enclosure  20  and thereby maintains the cover  14  in a spaced-apart configuration with respect to the base  12  when closed. This configuration thereby enable items that expand while cooking such as breads to have enhanced cooking results. 
         [0054]    Another aspect of the invention relates to using grill spacers  80 , such as are illustrated in  FIGS. 10 and 11 , to maintained the cover  14  in a generally parallel but spaced-apart relationship from the base  12 . The grill spacers  80  have a channel  82  formed therein. The channel  82  is adapted to receive at least a portion of the base side handle  30 . The cover side handle  50  rests on an upper surface of the grill spacer  80 . The height of the grill spacer  80  thereby determines the spacing between the cover  14  and the base  12 . 
         [0055]    While not illustrated, the grill spacer  80  may include at least two stepped regions. Varying the insertion of the base side handle  30  into the channel  82  thereby enables the cover side handle  50  to selectively engage one of the stepped regions to thereby provide adjustable spacing between the cover  14  and the base  12 . 
         [0056]    One of the grill spacers  80  may be attached to the base side handles  30  on opposite sides of the base enclosure  20 , as illustrated in  FIGS. 12-13 . As illustrated, the base side handle  30  is positioned in the channel  82  ( FIG. 12 ) and then the cover  14  is closed until the cover side handle  50  rests on the upper edge of the grill spacer  80  ( FIG. 13 ). 
         [0057]    In another configuration, the microwave grill  10  includes at least one additional grill element  90  such that there would be at least three grill elements in an at least partially overlapping configuration, as illustrated in  FIG. 14 . The additional grill element may be positioned below the base  12  or above the cover  14 . Similar to the other grill elements, the additional grill element would have an enclosure extending over at least a portion of the additional grill element to facilitate moving the additional grill element. 
         [0058]    In yet another configuration, multiple microwave grills  10  are adapted for stacking, as illustrated in  FIG. 15 . When stacking multiple microwave grills  10 , a lower surface of the base  12  sits on an upper surface of the cover  14 . The configurations of these components reduces the potential of the microwave grills  10  moving with respect to each other. 
         [0059]    In another configuration that is illustrated in  FIG. 16 , a support  100  is placed beneath the microwave grill  10  to raise the microwave grill  10  above a lower surface of the microwave over. The support  100  mates with the lower surface of the microwave grill  10  and resists unintended movement of the components with respect to each other such as when heating in a microwave over. 
         [0060]    In operation, the microwave grill  10  is preheated in a microwave oven (not shown). The cover  14  is opened and food is placed on the base grill element  22 . The cover  14  is then closed and the microwave grill  10  is heated in the microwave to thereby cook the food. Food cooked in the microwave grill  10  has a flavor and appearance that are similar to food cooked on conventional grills. The microwave grill  10  is suitable for use with a wide range of foods such as steaks, hamburgers, bacon, poultry, fish, grilled sandwiches and breads. It is also possible to cook with the microwave grill  10  using the cover  14  in an open position where the cover  14  is generally parallel to the base  12 . 
         [0061]    Alternatively, the microwave grill  10  may be preheated in a microwave oven (not shown) and then residual heat is used for cooking food. In this method, the cover  14  is opened and food is placed on the base grill element  22 . The cover  14  is then close and the food is allowed to cook in the microwave grill  10 . This method is particularly useful for cooking food like shrimp. 
         [0062]    It is contemplated that features disclosed in this application, as well as those described in the above applications incorporated by reference, can be mixed and matched to suit particular circumstances. Various other modifications and changes will be apparent to those of ordinary skill.