Abstract:
An indoor grill includes a system for retaining a desired amount of heat and smoke during cooking, while passing excess smoke through a filtering system. A water tray is disposed below the heating element, thereby resisting a tendency for dripping grease to create excessive smoke. A hood includes interior and exterior portions, with a space defined therebetween, and the space being accessible along the bottom edge of the hood. A filtration system is connected to the space between the interior and exterior housing portions. Smoke is drawn into the space between the inner and outer hood from the bottom edge, permitting some smoke to remain within the hood for flavoring. When the hood is opened, the hood&#39;s edge is raised, raising the entrance to the space between the inner and outer portions up towards the smoke that remained within the hood, and drawing that smoke into the filtration system.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. provisional patent application Ser. No. 61/986,474, filed Apr. 30, 2014, and entitled “Electric Grill.” 
    
    
     TECHNICAL FIELD 
     The present invention is related to indoor grills. More specifically, an electric grill with a system for controlling cooking temperature and limiting the exit of smoke during and after cooking is provided. 
     BACKGROUND INFORMATION 
     Grilling is a preferred means of preparing many different foods. Grilling allows that to drip away from the food before it is consumed, resulting in healthier, lower fat food. Grilling also improves the flavor of many foods. The “grill marks” produced where the food contacts the rack of the grill is the result of “caramelization,” or the browning of the sugars within the food, which improves the flavoring of the food. Additionally, the food may absorb various flavors from the smoke produced within the grilling process. 
     Grilling is typically performed outdoors, where charcoal or propane are burned to produce the necessary heat. Depending on the temperature and/or any precipitation, outdoor cooking may not always be desirable. Presently available indoor grills often do not reach the temperature necessary to produce caramelization, and therefore do not produce the same flavoring effects as outdoor grills. Many presently available indoor grills are also designed not to produce smoke, so that the flavoring effects of the smoke are unavailable. If smoke is produced, discharging the smoke into the interior of the house is undesirable. It is also desirable to control the heat on the exterior surfaces of indoor grills, due to their proximity to flammable materials as well as the possibility that children or others may accidently come into contact with an exterior grill surface. 
     An example of an indoor grill is U.S. Pat. No. 4,561,348. The grill disclosed therein includes an enclosure having an upper plate disposed below the outer housing top, creating an air space therebetween. The upper plate includes a suction opening having an electric fan to direct airflow into the space between the plate and the outer housing, where the air is heated by heating elements disposed therein. Apertures disposed near the heating elements allow the heated air to flow back into the cooking area. The motor for the fan blades also powers a second set of fan blades for directing airflow from outside of the apparatus to a space between the insulating upper wall and an outer casing. The outer casing is thereby kept cool to the touch. The airflow is intended to be hot enough to cook meat, but not hot enough to scorch meat. A second set of heat radiators is provided to scorch the surface of the meat. The fat tray is screened from hot airflow to prevent evaporation of the fat. Although this device provides the heat of a grill, it does not provide the smoke flavoring that a grill would provide. 
     U.S. Pat. No. 8,381,638 discloses a grill configuration having a forced air curtain. The forced air curtain is intended to limit smoke emissions from the grill. The grill includes a housing with an open top. Grilling bars are disposed a few inches below the open top. Heat sources such as charcoal receptacles with gas jets are disposed below them are positioned below the grilling bars, with a water tray positioned directly under the grilling bars. A pair of air manifolds are disposed on either side of the open top. One air manifold includes a supply fan, and the other air manifold includes an exhaust fan. Air is directed by the supply fan through the first manifolds, across the top of the grill, and into the second manifold through the exhaust fan, thereby trapping smoke below the airflow in order to flavor the food. The water tray is structured to resist burning and smoking of drippings. Air exiting the second air manifold is directed through a bubble filter having a reservoir filled with water. Although smoke is trapped during cooking, it would obviously not be trapped once the grill is opened to access the food after cooking. 
     U.S. Pat. No. 4,244,979 discloses an oven type apparatus. The apparatus includes an air passage disposed between the inner and outer walls of the main portion of the device. Louvered slots provide for limited airflow between the main compartment and the air passage. A blower is provided for blowing air in a circular path through the air passage, around the main compartment. A heater, followed by a water pan, are disposed after the blower. Air circulating through the air passage creates a pressure differential between the air passage and the main compartment, causing moisture to be drawn from the main compartment into the air passage, resisting any tendency for food to become soggy. At the same time, the circulating air provides for uniform heat distribution throughout the main compartment. The device is particularly useful for slow cooking of foods, grilling effects would not be accomplished by this device. 
     U.S. Pat. No. 5,197,379 discloses an outdoor cooker. The outdoor cooker includes a housing having double walled construction, having an insulating dead air space between the inner and outer walls. A fuel tray is disposed at the bottom of the housing. A deflector is located above the fuel tray, below the cooking grid. The V-shaped drip tray is disposed between the cooking grid and the deflector. Drippings are collected and prevented from contacting the burning fuel and being incinerated. The housing also includes a removable hood with an inspection opening. Food is thereby exposed to the heat indirectly rather than directly, thereby reducing the cooking temperature. Spit supports are provided so that a spit may be used to cook a large food item such as a turkey. Thus, by exposing the food to the heat indirectly, the device achieves a different purpose than that which would be achieved by grilling. 
     U.S. Pat. No. 4,510,854 discloses a compact barbecue oven. The barbecue oven includes a cabinet housing a rotisserie in the upper portion of the cabinet, a firebox in the lower portion of the cabinet, a burner for burning wood within the firebox, a flue, and an exhaust unit on top of the cabinet. The cabinet walls are made of spaced apart sheets of metal. An angled baffle wall is located between the rotisserie and the firebox, shielding food on the rotisserie from the firebox. The baffle wall permits air and smoke to flow between the baffle wall and the housing, so that the heat may cook the food and the smoke may impart flavor. The rotisserie is structured to turn a group of trays in a circular path. The firebox includes a vent to permit air to enter the firebox to support combustion. The flue is structured to receive smoke and air after it has passed from the firebox to the rotisserie area, and then back down towards a rear portion of the firebox, where a fan directs air and smoke into the flue. The exhaust unit may also be used to draw smoke and air out of the oven chamber. A drip pan is located at the bottom of the chamber, below the firebox. The pan includes a drain hose. Although this device is designed to use the smoke to impart flavor, it is not designed to cause grill marks or caramelization of the food. 
     U.S. Pat. No. 7,044,050 discloses an indoor barbecue system. The barbecue system includes a mechanism for withdrawing heat and smoke from the interior so that the enclosure can remain smoke-free during cooking. Some examples are structured to connect to an already existing dryer vent system. A mechanism for disseminating an artificially flavored air stream is disposed between the heat supplying mechanism and the food. The exhaust conduit includes a fan assembly for extracting smoke and heat through the exhaust conduit. A drip pan is disposed immediately below the cooking surface, so the drippings do not reach the heat supplying mechanism. Although this system will clearly dissipate smoke during cooking, it might be desirable instead to retain a certain amount of smoke for flavoring purposes, and then to dissipate this smoke at the conclusion of cooking. 
     U.S. Pat. No. 7,301,128 discloses a portable electric grill. The grill includes a central frame member having first and second hingedly attached frame members on either side. One of the hingedly attached frame members supports a griddle surface, and the other supports a grill surface. The grill plate and griddle plate have raised peripheral edges to retain grease drippings. The drippings are carried by drain tubes to a drip tray. The drip tray is located within the central frame member. The first and second frame members can be folded from a vertical storage and transportation position to a horizontal cooking position. The central frame member includes a removable vent plate wherein an air filter is disposed. An exhaust fan used to draw smoke and cooking fumes through the vent plate and filter, propelling the filtered air through an exhaust vent. With no lid, this device has no way to retain a certain amount of smoke in the cooking area for flavoring. 
     U.S. Pat. No. 5,862,741 discloses an indoor and outdoor smokeless grill. The exterior housing is a round a sleeve that is structured to be positioned above the stove. A grill is mounted on top of a round dish that sits on top of the sleeve. A water tray is disposed within the sleeve to catch drippings from the grill. The water tray is filled with water. The water in the water tray boils, turning to steam, and preventing the food from burning, by reducing the temperature of the heating air. In one example, the water container is connected to a bimetallic strip. When the bimetallic strip is heated, it pulls the water container upward, reducing the size of the air passage around the water container, and thereby controlling the extent to which the food is heated. This device will result in a different cooking effect than grilling: rather than producing grill marks and caramelization, this device will resist burning during cooking. 
     U.S. Pat. No. 6,363,842 discloses an indoor grill having a filter. The base includes a cooking surface. A post extends upward from the rear of the base to support a filter unit thereon. The filter system includes a hood for collecting smoke and other combustion byproducts, a ventilation system including a fan, and a replaceable filter. The grill is open, so smoke will either be absorbed by the filter system or dissipated into the surrounding air, leaving no way to retain a desired amount of smoke in the cooking area for flavoring. 
     U.S. 4,800,865 discloses a portable cooking device. The device includes a housing that is structured to overlie a conventional barbecue grill. The bottom surface of the housing is semi conductive of heat. A partition is disposed on either end of the cooking surface, with an opening defined in the housing on the opposite side of the partition to allow heat and smoke to pass around the edges of the cooking surface, around the partition, and then into the area where food is cooked. Vents are provided to allow heat and smoke to vent from a lower portion of the cooking chamber. This device does little to reduce the problem of smoke during indoor grilling. 
     Accordingly, there is a need for an improved indoor grill. There is an additional need for an indoor grill that approximates the cooking characteristics of an outdoor grill, including caramelization, grill marks, and smoke flavoring. There is a further need for an indoor grill that resists the passage of smoke out of the grill into the interior of the building. There is yet another need for an indoor grill that retains a desired amount of smoke within its hood, and then removes that smoke through its filtration system upon opening the grill. 
     SUMMARY 
     The above needs are met by an indoor grill. The indoor grill includes a base having a base housing having an open top. A heating element is disposed within the base housing. A rack is disposed above the heating element. A hood is hingedly secured to the base. The hood pivots between a closed position wherein the hood substantially covers the rack, and an open position. The hood includes an outer housing. The outer housing has a plurality of side walls, with the side walls each defining a bottom edge that is structured to abut the base when the hood is in its closed position. The hood also includes an inner housing. The inner housing defines a plurality of side walls, with the side walls each defining a bottom edge that is structured to be spaced from the base and the rack when the hood is in its closed position. The inner housing and outer housing define an open space therebetween and a smoke entrance between the bottom edges of the inner and outer walls. The indoor grill further includes a filtration system in communication with the open space between the inner housing and outer housing. The filtration system has a filter, as well as a fan that is structured to create an airflow from the open space between the inner and outer housings through the filter. 
     During cooking, a quantity of smoke is retained within the hood, and excess smoke is drawn into the space between the inner housing and outer housing, where it travels through the filter before exiting the grill. When the hood is opened, the smoke entrance around the bottom edge of the hood is raised above the grill rack, thereby drawing previously retained smoke into the smoke entrance and then through the filtration system. 
     These and other aspects of the invention will become more apparent through the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective front view of an indoor grill. 
         FIG. 2  is a perspective back view of the indoor grill of  FIG. 1 . 
         FIG. 3  is a front cross-sectional view of the indoor grill of  FIG. 1 . 
         FIG. 4  is a front perspective view of the indoor grill of  FIG. 1 , showing the lid open. 
         FIG. 5  is a top perspective view of the indoor grill of  FIG. 1 , showing the filter system cover removed and filter door partially opened. 
         FIG. 6  is a top perspective view of the indoor grill of  FIG. 1 , showing the filter removed from the filter system. 
         FIG. 7  is a top perspective view of the indoor grill of  FIG. 1 , showing the lid open, and grill racks removed. 
         FIG. 8  is a side cross sectional view of the indoor grill of  FIG. 1 , showing the lid partially opened. 
         FIG. 9  is a top cross-sectional view of the lid, showing a pair of sliding doors covering openings defined within the interior lid housing. 
         FIG. 10  is a side view of a side wall of the interior lid housing, showing a door of  FIG. 9  partially opened. 
         FIG. 11  is a front cross-sectional view of another example of an indoor grill. 
         FIG. 12  is a front cross-sectional view of yet another example of an indoor grill. 
     
    
    
     Like reference characters denote like elements throughout the drawings. 
     DETAILED DESCRIPTION 
     Referring to the drawings, an indoor grill  10  is shown. Referring to  FIGS. 1-3 and 8 , the grill  10  includes a base  12  and a hood  14  secured to the base  12  by the hinge  16  ( FIGS. 4 and 8 ). 
     Referring to  FIGS. 1-3 and 7-8 , the base includes a housing  18  having a bottom  20  and side walls  22 . In this context, “side” includes the front side and back side as well as the right and left sides, and may also include a number of sides that is equal to, greater than, or less than four. A heating element  24  is disposed within the housing  18 . In the illustrated example, the heating element  24  is an electric heating element. At least one grill rack is disposed above the heating element  24 . In the illustrated example, a grill rack  26  is disposed above a grill rack  28 , with the grill rack  28  defining smaller openings therein than the grill rack  26 . Rack supports  30  protrude inward from the walls  22  to support the racks  26 ,  28 . A water tray  32  is disposed below the heating element  24 . A slot  34  is defined within one of the walls  22  to facilitate removal and replacement of the water tray  32 . 
     Continuing to refer to  FIGS. 1-4 and 8 , the hood  14  includes an inner housing  36  and an outer housing  38 . The inner housing  36  includes a top  40  and sides  42 . Similarly, the outer housing includes a top  44  and sides  46 . As before, “sides” may include the front side and back side as well as right and left sides, and may include a number of sides that is equal to, greater than, or less than four. The inner housing  36  is generally nested within the outer housing  40 , and a space  48  is defined between the inner housing  36  and outer housing  38 . The sides  46  of the outer housing  38  include edges  50  that are structured to abut the base  12  when the hood  14  is closed. The sides  42  of the inner housing  36  include edges  52  that are structured to be spaced from the base  12  when the hood is closed. The space  48  between the inner housing  36  and outer housing  38  is therefore in communication with the interior  54  of the hood  14 . 
     Referring to  FIGS. 3, 5-6, and 8 , a filtration system  56  is operatively connected to the space  48  between the inner hood  36  and outer hood  38 . In the illustrated example, the filtration system  56  is disposed on top of the hood  14 , and communicates with the space  48  through the opening  57  within the top  44  of the outer hood  38 . The filtration system includes a housing  58  including a plurality of sides  60  and a top  62  defining an opening  64  therein. The filtration system includes a filter  66 , which in the illustrated example is the same type of filter that is used in a typical hood over a kitchen stove. At least one fan  68  is disposed adjacent to the filter  66 . The fan  68  is structured to create an airflow from the space  48  through the filter  66  and then through the opening  64 . A slot  70  is defined within one side  60  of the housing  58  to facilitate removal and replacement of the filter  66 . In the illustrated example, the slot  70  may be covered by the door  72 , which in the illustrated example is a sliding door  72 . The illustrated example of the filtration system  56  includes a removable cover  74  ( FIGS. 1-3 ). The illustrated example of the cover  74  includes an open back  76 , and is structured to direct air flow from the housing  58  towards the back of the grill  10 . 
     Referring to  FIGS. 1, 3-4, and 7-8 , the heating element  24  in the illustrated example is an electric heating element, although the invention is not restricted to electric heating elements. Heat may be supplied by liquid or solid burnable fuels without departing from the scope of the invention. Some examples of the heating element  24  may be connected to a power supply (not shown, but well-known in the art), through a temperature control mechanism and possibly a timing control mechanism. Different temperature and/or timing mechanisms, both of which are well-known in to those skilled in the art, can be used without departing from the scope of the invention. Additionally, the power supply for the fan  68  may be incorporated into the power supply for the heating element  24 , with or without a separate on/off control, or may be a separate power supply. In the illustrated example, a separate switch  128  is provided to control the fan  68 . An indicator light  126  may optionally be provided to show when power is being applied to the heating element  24 . Temperature can be controlled by a simple potentiometer connected to the power supply for the heating element for regulating the voltage and/or current supplied to the heating element. Alternatively, temperature can be controlled by providing a temperature-setting control, as well as a temperature sensor such as a bimetallic strip or other known temperature sensor within the space  54 . Such temperature controls are well-known in conventional ovens and therefore not described further herein. In either case, a knob  124  may be used to permit a user to control the temperature. Temperature may also be monitored by a user using an external temperature gauge  122 . Timing may be controlled by any well-known timer, including one that is structured to cut off power to the heating element  24  upon completion of the predetermined cooking time. Such timers are conventional in toasters, toaster ovens, etc., and are therefore not described further herein. 
     In use, water is placed within the water tray  32 , and the tray  32  is placed below the heating element  24 . The filter  66  is placed within the filtration system  56  if it is not already in place, and the door  72  is closed. The cover  74  is placed over the housing  58  if it is not already in place. The hood  14  is raised, and food to be cooked is placed on the rack  26 . The rack  28  serves to catch any food that may fall through the rack  26 . The hood  14  is closed. Power is supplied to the heating element  24  and fan  68 . Heat is retained within the space  54 , thereby increasing the cooking temperature and increasing the likelihood of caramelization and grill marks. The space  48  resists excessive heating of the outer housing  38  of the hood  14 , thus enhancing the safety of an individual who may touch the outer hood  38  during cooking. Grease and fat that drips from the food will largely be captured by the water tray  32 , reducing but not eliminating the production of smoke. The smoke that is produced will be retained to a limited extent within the space  54 . When the smoke fills the space  48 , the smoke will begin to pass into the space  48 , where it will be drawn into the filter  66  before the filtered air  68  is expelled through the openings  64 ,  76 . Thus, some smoke is retained for flavoring of the food, but the amount of smoke retained is limited. 
     Because some smoke is retained within the space  54 , a means of ensuring that the unfiltered smoke does not pass into the interior of a building in which the grill  10  is being used is desired. The manner in which smoke is drawn into the space  48  is specifically designed for this purpose. When the hood  14  is closed, only limited smoke is drawn past the bottom edge  52  of the inner housing  36  and into the space  48 . When the hood is opened, as shown in  FIG. 8 , the bottom edges  50 ,  52  of the hood  36  are raised above the base  12 , the entrance  53  to the space  48  passes over the smoke that was immediately beforehand contained under the hood  14 . As this edge passes over that smoke, the smoke will be drawn into the space  48  and drawn through the filtration system  56 , thus resisting any tendency of smoke to exit the grill unfiltered when the hood  14  is opened. 
     Some examples of the grill  10  may include an additional smoke control system, which is illustrated in  FIGS. 9-10 . In these examples, the sides  42  of the interior housing  36  define at least one opening  78  therein. The openings  78  may be covered by a door  80  that is operable from outside the hood  14  when the hood  14  is closed. In the illustrated example, the door  80  is a sliding door  80  that is retained by lips  82 . A tab  84  on the door  80  protrudes through a slot  86  defined within the side  46  of the exterior housing  38 , permitting the tab  84  to be grasped to open and close the door  80  while the hood  14  is closed. The door  80  may be kept fully closed, partially closed, or fully open during cooking, depending on the amount of smoke generated and desired level of smoke retention during cooking. Before opening the hood  14 , the door  80  may be fully opened to withdraw some smoke from the interior region  54  into the space  48  prior to opening the hood  14 . 
     Other variations of the indoor grill are illustrated in  FIGS. 11-12 . The indoor grills  88 ,  90  are similar to the grill  10  in every respect except for the specific manner in which smoke is drawn from the space between the interior and exterior hood housings into the filtration system and out of the grill. The grills  88 ,  90  each have hoods  92 ,  94  having interior walls  96 ,  98  and exterior walls  100 ,  102  defining a space  104 ,  106  therebetween. The grills  88 ,  90  include a conduit  108 ,  110  within the space  104 ,  106  into which smoke entering the space  104 ,  106  is directed. The conduit  108  is disposed in a lower portion of the space  104 , while the conduit  110  is disposed in an upper portion of the space  106 . The conduits  108 ,  110  each lead into a filtration system  112 . The illustrated example of the filtration system  12  includes a filter  114  disposed adjacent to a fan  116 . In the illustrated example, a flexible conduit  118  is provided between the conduit  108 ,  110  and the housing  120  for the filter  114  and fan  116 . Some examples of the filtration system  112  are structured to direct filtered air into a pre-existing duct system, for example, a dryer duct or intake of a range hood, so that filtered air, and any smoke that may have passed through the filtration system  112 , can be directed to the exterior of the building in which cooking is performed. 
     The indoor grill therefore provides a means of utilizing a controlled amount of smoke for food flavoring during cooking, while resisting passage of unfiltered smoke to the exterior of the grill. The grill further provides a means of retaining heat within the grill during cooking to increase the likelihood of caramelization and grill marks, while insulating the exterior of the grill from heat for enhanced safety. Additionally, the grill provides a means of retaining a quantity of smoke during cooking, while also directing the retained smoke through the filtration system before or upon opening of the grill. 
     A variety of modifications to the above-described embodiments will be apparent to those skilled in the art from this disclosure. Thus, the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention. The appended claims, rather than to the foregoing specification, should be referenced to indicate the scope of the invention.