Patent Publication Number: US-9897329-B2

Title: Cooktop with downdraft ventilator

Description:
FIELD OF THE INVENTION 
     The invention relates generally to ventilators for cooktops and, in particular, to downdraft ventilators. 
     BACKGROUND OF THE INVENTION 
     Systems for exhausting cooking fumes that are created during cooking procedures using cooktops are known. Overhead ventilation hoods are commonly used in both commercial and residential kitchens. Some homeowners do not like how overhead ventilation hoods look. Some installation locations of cooktops, such as separate island counter or end peninsular counter locations, can make mounting of overhead ventilation hoods difficult. 
     Flush or fixed surface-mounted ventilators have been used in situations in which overhead ventilation hoods are not desired. Such fixed surface-mounted ventilators tend to draw air transversely across the cooktop, which may draw cool ambient air across the food being cooked. To remedy this, telescoping downdraft ventilators have been provided. Telescoping downdraft ventilators have lessened the issues of drawing cool ambient air across food because they have inlets that draw air at a location that is vertically spaced above the cooking surface. This allows the telescoping downdraft ventilators to draw cooking fumes upwardly away from the food being cooked instead of drawing ambient air transversely across the cooking surface. 
     However, telescoping downdraft ventilators are often complex and expensive. Telescoping downdraft ventilators include numerous moving parts that may require maintenance over time. 
     SUMMARY OF THE INVENTION 
     The present inventors have recognized that relatively high-powered fans can be useful for fixed surface-mounted downdraft ventilators in cooktops. Using high-powered fans for fixed surface-mounted downdraft ventilators allows air to be drawn from higher above the cooking surface, instead of across the cooking surface which may draw cool ambient air across the food. The present inventors have further recognized that air leaks may occur in ventilator systems at joints defined between components at a cooktop panel. One such joint is where a cooktop panel and an underlying plenum connect to each other. Another such joint is where a cooktop panel and an overlying vent grill connect to each other. The present inventors have realized that assembly fit-up between cooktop panel and plenums and/or vent grills can be difficult to do consistently and/or accurately. That is because there can be relatively large variations between dimensions and flatness of cooktop panels because such panels are formed by punch-pressing and remain somewhat flexible after they are formed. Such variations in flatness and flexibility of the cooktop panels make such components difficult to form airtight seals against. The present inventors have further recognized that in gas cooktops, air leaks in fixed surface-mounted downdraft ventilators can detrimentally influence flame patterns from the gas burners. This may be due to ancillary airflows being created near the cooking surface that flow into the leak locations. Such ancillary airflows may otherwise compromise the integrity of the flame(s). Such issues can be worsened by using relatively high-powered fans in ventilation systems. Therefore, the present invention contemplates a cooktop and/or methods of assembling or installing cooktops that address these and other inventor-identified problems and drawbacks of the prior art. 
     Thus, in accordance with an aspect of the invention, a cooktop is provided that has an interconnected panel, plenum, and vent grate that are arranged in a layered and sealed configuration that is substantially airtight. The cooktop may be a gas cooktop. The gas cooktop may include a panel for supporting multiple gas burners and that has an upper surface and an opposing lower surface. The panel may have a vent opening that extends through the panel. A vent grate extends away from the upper surface of the panel. The vent grate is aligned with the vent opening so that cooking fumes that are created during a cooking process can be directed through the vent grate and the vent opening. This is done to exhaust the cooking fumes away from the panel. The vent grate includes an upper wall having openings through which the cooking fumes can flow. The vent grate also includes a side wall that extends downwardly from the vent grate upper wall. A plenum extends away from the lower surface of the panel. The plenum is aligned with the vent opening. In this way, the cooking fumes that are draw through the vent grate and vent opening are directed through the plenum for exhausting out of the system. A seal arrangement is provided between the panel and the vent grate and the panel and the plenum. This allows the upper and lower surfaces of the panel to be sealed against the vent grate and plenum, respectively. The seal arrangement between the panel and the vent grate also may include a retention tab that is fastened to an embossed area of the plenum, ensuring a precise location of the seal. 
     In accordance with another aspect of the invention, the seal arrangement includes a plenum seal and a vent seal. 
     In accordance with another aspect of the invention, the plenum includes a flange that extends outwardly from an upper end thereof. The plenum seal is substantially flat and is sandwiched between the flange of the plenum and the lower surface of the panel. Multiple fasteners extend between and draw the flange of the plenum and the panel toward each other. This compresses the plenum seal between the flange of the plenum and the lower surface of the panel. 
     In accordance with another aspect of the invention, the panel defines a main portion and a raised shelf that extends about the vent opening. The raised shelf includes an edge that defines the vent perimeter. The raised shelf of the panel may include an angled wall that extends angularly from the main portion of the panel and an upper wall that extends from the angled wall of the raised shelf. The edge of the raised shelf may be defined at an end of the upper wall. The upper wall of the raised shelf may be generally parallel to the main portion of the panel. 
     In accordance with another aspect of the invention, the vent seal may include an inner collar that extends downwardly through the vent opening in a direction that is generally parallel to the plenum. The inner collar of the vent seal may extend downwardly beyond the remainder of the vent seal. The inner collar of the vent seal may be nested inside of an upper portion of the plenum. A rib may extend outwardly from the inner collar of the vent seal in a direction that faces toward an outer perimeter of the panel. The rib may define a first rib upon the inner collar and a second rib may be provided that extends from the inner collar in a direction that faces toward the outer perimeter of the panel. The first and second ribs may be parallel to and spaced from each other along a length of the inner collar. 
     In accordance with another aspect of the invention, a portion of the panel through which the vent opening extends is held within a space that is between the rib of the vent seal and an inner segment of an upper wall of the vent seal. Such portion of the panel may be the raised shelf that extends about the vent opening. 
     In accordance with another aspect of the invention, the vent seal may include an upper wall that extends generally orthogonally away from the vent opening. The vent grate may engage the upper wall of the vent seal. The upper wall of the vent seal may include an inner segment that is relatively nearer to the vent opening and an outer segment that is relatively further from the vent opening. The outer segment of the vent seal upper wall may be elevated with respect to the inner segment of the vent seal upper wall. The vent seal upper wall may include an angled segment that connects the inner and outer segments of the vent seal upper wall. 
     In accordance with another aspect of the invention, the vent seal further includes a side wall that extends generally orthogonally, for example, generally vertically, between the vent seal upper wall and the panel. The vent seal side wall may hold the vent seal upper wall in a position that is spaced from the upper surface of the panel. An engagement of the vent grate side wall and vent seal upper wall may push or bend the vent seal upper wall relatively closer to the upper surface of the panel. In this way, the vent seal upper wall may define two positions or heights with respect to the panel, depending on whether or not the vent seal upper wall is being engaged by the vent grate. A first height with respect to the upper surface of the panel may be defined when the vent grate is removed from the gas cooktop, whereby the vent grate does not engage the vent seal. A second height with respect to the upper surface of the panel that is shorter that the first height may be defined when the vent grate is mounted to the gas cooktop, whereby the vent grate engages the vent seal. 
     In accordance with another aspect of the invention, the vent grate may include a side wall that engages the upper wall of the vent seal and a lower wall that extends from the vent grate side wall and outwardly beyond the vent seal. The vent grate lower wall may extend angularly downwardly and outwardly from an outer surface of the vent grate side wall. 
     These and other objects, advantages, and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings illustrate the best mode currently contemplated of practicing the present invention. 
       In the drawings: 
         FIG. 1  is a pictorial view of a cooktop having a downdraft ventilator in accordance with the present invention; 
         FIG. 1 a    is pictorial view from the front of the cooktop of  FIG. 1 ; 
         FIG. 1 b    is an exploded view of the cooktop internal components; 
         FIG. 2  is a pictorial view of a variant of the cooktop and downdraft ventilator of  FIG. 1 ; 
         FIG. 3  is an exploded view of portions of the cooktop and downdraft ventilator of  FIG. 1 ; 
         FIG. 4  is an exploded view of portions of the cooktop and downdraft ventilator of  FIG. 2 ; 
         FIG. 5  is a close-up pictorial view of a portion of a panel of the cooktop of  FIG. 1 ; 
         FIG. 6  is a close-up pictorial view of a plenum seal according to the present invention; 
         FIG. 7  is a pictorial view from above of the vent grate of  FIG. 1 ; 
         FIG. 8  is a pictorial view from below of the vent grate of  FIG. 1 ; 
         FIG. 9  is a pictorial view from above of the vent grate of  FIG. 2 ; 
         FIG. 10  is a pictorial view from below of the vent grate of  FIG. 2 ; 
         FIG. 11  is partial cross-sectional view of a portion of the cooktop of  FIG. 1 ; 
         FIG. 12  is partial cross-sectional view of a portion of the cooktop of  FIG. 2 ; 
         FIG. 13  is an isometric view of an alternative embodiment of the vent seal of  FIG. 3 ; and 
         FIG. 14  is a partial cross-sectional view of an alternative embodiment of a portion of the cooktop according to  FIG. 2 . 
     
    
    
     In describing the preferred embodiment of the invention which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the words “connected”, “attached”, or terms similar thereto, are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The cooktop with downdraft ventilator of the present invention generally includes an interconnected panel, plenum, and vent grate that are arranged in a layered and sealed configuration that is substantially airtight. The cooktop may be a gas cooktop but the invention is applicable to any cooktop. The cooktop may also include a panel for supporting multiple burners and that has an upper surface and an opposing lower surface. The panel may have a vent opening that extends through the panel. A vent grate extends away from the upper surface of the panel. The vent grate is aligned with the vent opening allowing cooking fumes to be directed through the vent grate and the vent opening. The vent grate includes an upper wall having openings through which the cooking fumes can flow. The vent grate also includes a side wall that extends downwardly from the vent grate upper wall. A plenum extends away from the lower surface of the panel. The plenum is aligned with the vent opening. A seal arrangement is provided between the panel and the vent grate and the panel and the plenum. This allows the upper and lower surfaces of the panel to be sealed against the vent grate and plenum, respectively. A retention tab incorporated into the seal between the vent grate and the plenum may be fastened to the plenum, ensuring a precise location of the seal. 
     Nontraditional manufacturing methods may also be employed when manufacturing the cooktop components. Soft tooling may be used to lower tooling costs and deliver quality parts with lower than typical lead times. 
     The inventive cooktop with downdraft ventilator is generally shown in  FIGS. 1-14 . The construction of such a cooktop with burners is well known to those skilled in the art and therefore a detailed description thereof is not necessary to fully understand the present invention which is directed to novel improvements in the construction of the cooktop and its venting system. 
     Referring to the drawings, it can be seen that  FIGS. 1, 1   a ,  1   b , and  2  illustrate work surfaces  5  in which cooktops  10  with downdraft ventilators  12  according to the invention are mounted. As is explained in greater detail elsewhere herein, seal arrangements  13  and  19  are provided between various components of the cooktops  10  and ventilators  12 . The seal arrangements  13  and  19  are configured as to establish substantially airtight interfaces at such component interconnections between the ventilators  12  and cooktops  10 . The cooktops  10  are illustrated as being gas cooktops  10 . It is understood that the ventilator  12  may instead be used with a non-gas cooktop such as induction or other electric cooktop.  FIGS. 1 and 1   a  illustrate an air flow channel  9  located on both sides of a vent grate  62  that assists in properly directing air flow from the cooking area. 
     Looking now to  FIG. 1 b   , an exploded view of an exemplary cooktop can be seen. A burner box  11  generally encloses the internal components of the cooktop assembly. Rails  15  attach and seal to the burner box  11  to provide structural support to the downdraft components of  FIGS. 5-10 . Burner seats  17  provide structural support for the burners  16  and burner grates  18  of  FIGS. 1-2 . A burner box seal  19 , which may be a die cut extrusion, seals the connection between the burner box  11  and the panel  14 . Burner valve brackets  21  support the burner valves  25  and attach them to the burner box  11 . Weld studs  23  provide versatility and rigid installation of the burner box  11  into kitchen cabinetry or a countertop by allowing installation either above or below the countertop. 
     Referring now to  FIGS. 1 and 2 , ventilator  12  is mounted to a panel  14  that supports multiple burners, shown here as gas burners  16 . The panel may be embossed at all locations where a fastener is used. Embossing prevents over- and under-tightening of the respective fastener during installation and assembly of the cooktop. Burner grates  18  are supported by the panel  14  and extend over the burners  16 . Referring now to  FIGS. 3 and 4 , panel  14  has opposing upper and lower surfaces  20 ,  22 . An outer perimeter  24  extends about the outer periphery of a main portion  26  of the panel  14 . A raised shelf  28  extends upwardly from an intermediate location of the panel main portion  26 . As shown in  FIG. 5 , the raised shelf  28  includes angled wall  30  that extends angularly upward from the panel upper surface  20 . An upper wall  32  of the raised shelf  28  extends inwardly from an outer segment of the angled wall  30 . The upper wall  32  of the raised shelf  28  is generally parallel to the panel upper surface  20 . The raised shelf  28  includes an edge  34  that defines a vent perimeter  36 . A vent opening  38  extends through the vent perimeter  36  and thus the panel  14 . 
     Referring again to  FIGS. 3 and 4 , ventilator  12  includes a fan  40  that creates an exhaust airflow which draws cooking fumes away from the space above the panel  14 . The exhaust airflow moves the cooking fumes from the fan  40  to a relatively less objectionable exhaust location in a known manner. A plenum  42  extends away from the panel lower surface  22 . The plenum  42  interconnects the fan  40  and the panel  14 . The plenum  42  has an opening that is aligned with the vent opening  38 . In this way, cooking fumes that are drawn through the vent opening  38  are directed through the plenum  42 , to the fan  40 , and then exhausted to a suitable location. A flange  44  extends peripherally out from an upper end of the plenum  42 . The plenum flange  44  defines a flat upper surface  46  that is rectangular in profile shape. The plenum flange upper surface  46  faces toward the panel lower surface  22 . Further, the plenum flange  44  may be arranged entirely outside of the raised shelf  28 . 
     As shown in  FIGS. 11 and 12 , in these embodiments, an inner-most portion of the plenum flange  44  extends slightly below the raised shelf  28 . The plenum flange  44  projects about half-way across the length of the raised shelf angled wall  30 . Regardless, the plenum flange  44  extends sufficiently across part of the panel lower surface  22  of the main to be sealed against it by way of the seal arrangement  13 . 
     Referring now to  FIGS. 3 and 4 , seal arrangement  13  includes a plenum seal  48 . Plenum seal  48  serves as a gasket between the flat surfaces of the panel lower surface  22  and the plenum flange upper surface  46 . Referring again to  FIGS. 11 and 12 , the plenum seal  48  is sufficiently thick and resilient or deformable to accommodate deviations of the panel lower surface  22  and the plenum flange upper surface  46  from being truly flat. In this way, the plenum seal  48  conforms to irregularities and substantially fills void spaces between the panel lower surface  22  and the plenum flange upper surface  46 . Further, as fasteners  50  ( FIG. 11 ) tighten the panel  14  and plenum flange  44  against each other, the plenum seal  48  is sandwiched or compressed and fills any void space therebetween. The fasteners  50  may include any fastening device in the art; however, the preferred fastener is a screw and a square-shaped trimmer nut combination. The fasteners  50  make the layered interconnection of the plenum  42 , plenum seal  48 , and panel  14 , substantially airtight. 
     Referring now to  FIG. 6 , plenum seal  48  has a substantially rectangular perimeter shape. Opposing end segments  52 ,  54  are interconnected at their ends by opposing side segments  56 ,  58 . Cutaways  60  that are spaced from each other extend into the side segments  56 ,  58 . The cutaways  60  align with holes (not shown) in the panel  14  and plenum flange  44  through which the fasteners  50  extend ( FIG. 11 ). In this way, multiple fasteners  50  clamp the panel  14  and plenum flange  44  to each other at multiple spaced apart locations about the vent opening  38 . The fasteners  50  do not extend through the plenum seal  48 , per se, but instead extend outwardly of the plenum seal  48  by way of passing through the cutaways  60 . 
     Referring again to  FIGS. 3 and 4 , the ventilator  12  further includes a vent grate  62 . Each vent grate  62  has a perimeter shape that corresponds to the perimeter shapes of the burner grates  18  being used with a particular cooktop  10 . The burner grates  18  of  FIGS. 1 and 3  have arcuate inwardly facing segments, such that the vent grate  62  has corresponding arcuate outwardly facing segments in its perimeter shape. The burner grates  18  of  FIGS. 2 and 4  have straight inwardly facing segments, such that the vent grate  62  has corresponding straight outwardly facing segments in its perimeter shape. 
     Referring now to  FIGS. 7-10 , each vent grate  62  includes a top wall  64  that has openings  65  extending therethrough. The openings  65  are defined between adjacent louvers  66 . The louvers  66  are generally flat and arranged nearly upright or vertical. However, the louvers  66  are angled or tipped downwardly from being truly vertical, toward operator controls on the cooktop  10  ( FIGS. 1 and 2 ). This arrangement allows the ventilator  12  to pull air through the vent grate  62  from a generally central location above the panel  14 . Each vent grate  62  has multiple interconnected side walls  68 . The side walls  68  extend downwardly from the outer perimeter of the top wall  64 . Multiple feet  70  extend downwardly from each of the vent grates  62 , away from the top wall  64 . The feet  70  are spaced about a periphery of the vent grates  62  and are set upwardly or recessed with respect to a lowermost portion of the vent grates  62 . The feet  70  are preferably made from a resilient material and sit directly upon the panel  14  to support the vent grates  62 . 
     The embodiment of  FIGS. 7 and 8  further includes lower walls  72 . The lower walls  72  extend angularly from the longer pair of side walls  68  of that embodiment. Lower walls  72  intersect the respective side walls  68  at an outer surface thereof, about one quarter of the way up from the bottom of the side walls  68 . The embodiment of  FIGS. 9 and 10  further includes outer flanges  74 . The outer flanges  74  extend generally orthogonally away from middle portions of respective side walls  68 . The outer flanges  74  support the feet  70  of this embodiment. 
     Referring now to  FIGS. 8 and 10 , regardless of the particular configuration of the vent grate  62 , lower edges  76  are defined at the bottoms of the side walls  68 . In the embodiment of  FIG. 8 , the lower edges  76  define a U-shaped profile, with three side walls  68  extending downwardly to a common height. In the embodiment of  FIG. 10 , the lower edges  76  extend continuously about a rectangular lower perimeter shape. The lower edges  76  are configured to engage a vent seal  80  that is part of the seal arrangement  13 . 
     Referring again to  FIGS. 3 and 4 , vent seal  80  is provided between the panel  14  and the vent grate  62 . The vent seal  80  is sufficiently thick and resilient or deformable to accommodate deviations of the panel upper surface  20  and the vent grate side wall lower edges  76  from being truly flat. In this way, the vent seal  80  conforms to irregularities and substantially fills void spaces between the panel upper surface  20  and the vent grate side wall lower edges  76 . Moreover, the weight of the vent grate  62  that pushes against the vent seal  80  allows the vent seal  80  to be sandwiched or compressed and to fill any void space between the panel  14  and vent grate  62 . This makes the layered interconnection of the vent grate  62 , vent seal  80 , and panel  14 , substantially airtight. 
     Referring again to  FIGS. 11 and 12 , vent seal  80  includes an inner collar  82  that extends vertically or downwardly with respect the remainder of the vent seal  80 . Inner collar  82  extends into the vent opening  38 , so that the inner collar  82  nests inside of an upper portion of the plenum  42 . A rib or, as shown, a pair of ribs  84 ,  86  extends outwardly from an outer surface  88  of the inner collar  82 . The ribs  84 ,  86  are spaced from each other vertically or along the length of the inner collar  82 . In one embodiment, the ribs  84 ,  86  extend continuously about the entire perimeter of the inner collar  82 . In another embodiment, multiple discrete sets of ribs  84 ,  86  extend along less than the entire perimeter of the inner collar  82 . In one such exemplary embodiment four sets of ribs  84 ,  86  are provided that wrap around the four corners of the inner collar  82 , whereas the majority of the outer surface  88  of the inner collar  82  is flat or without ribs  84 ,  86 . 
     Still referring to  FIGS. 11 and 12 , the vent seal  80  includes an upper wall  90  that extends generally orthogonally away from the vent opening  38 . Vent seal upper wall  90  includes an inner segment  92  that connects to the inner collar  82 . An angled segment  94  connects to the inner segment  92 . The angled segment  94  extends angularly upwardly and outwardly away from the inner segment  92 . In the embodiment of  FIG. 12 , a leg  95  extends downwardly at an angle, away from the intersection of the inner and angled segments  92 ,  94  of the vent seal upper wall  90 . Referring again to both  FIGS. 11 and 12 , an outer segment  96  of the vent seal upper wall  90  connects to and extends away from the angled segment  94 . The outer segment  96  of the vent seal upper wall  90  is spaced from the panel  14 . In a resting state in which the vent grate  62  is not mounted to the cooktop  10 , the outer segment  96  of the vent seal upper wall  90  is substantially horizontal and parallel to the panel  14 . A side wall  98  extends generally orthogonally or vertically between the outer segment  96  of the vent seal upper wall  90  and the panel upper surface  20 . A bottom edge  100  of side wall  98  engages the upper surface  20  of the panel  14 . 
     Still referring to  FIGS. 11 and 12 , in the complete assemblage, the vent seal  80  engages the panel  14  at multiple locations and also engages the plenum  42  and vent grate  62 . As mentioned elsewhere, the vent seal inner collar  82  is nested within the plenum  42 . The lower rib  86  of the vent seal inner collar  82  may engage an inwardly facing surface of the plenum  42 . The upper wall  32  of the panel raised shelf  28  fits snugly between an upper surface of the upper rib  84  and a lower surface of the inner segment  92  of the vent seal upper wall  90 . In the embodiment of  FIG. 12 , the leg  95  of the vent seal  80  engages an upper surface of the raised shelf angled wall  30  of the panel  14 . Referring again to  FIGS. 11 and 12 , of the vent seal  80 , the upper wall angled and outer segments  94 ,  96  and the side wall  98  generally define an upside-down U-shaped perimeter of a void space  102  below. 
     Looking now to  FIG. 13 , an alternative embodiment of the vent seal  80  is shown. The alternative vent seal  80   a  includes a mounting tab  106  with a mounting tab hole  107 . An appropriate fastener may be inserted through the mounting tab hole  107  to provide a safeguard in holding the vent seal  80   a  in place. Such a configuration is demonstrated in  FIG. 14 , where the alternative vent seal  80   a  is installed in a similar fashion as the vent seal  80  of  FIG. 12 . Referring back to  FIG. 14 , a fastener, such as a mounting tab screw  108 , may be affixed in the plenum  42 . The plenum may include an embossing  45  in the area that the mounting tab screw is affixed to add structural rigidity to the plenum  42 . The mounting tab  106  is bent so that it is flush with the plenum  42  in the direction as indicated by arrow  109 . The mounting tab screw is placed through the mounting tab hole  107  and through the plenum  42  wall, affixing the mounting tab  106  flush against the plenum  42 . 
     Now transitioning to  FIG. 11 , the void space  102  provides enough room to house a head of the fastener  50  therein and allow the vent seal upper wall  90  to flex downwardly when the weight of the vent grate  62  pushes it down. Accordingly, the vent seal upper wall  90  defines two positions or heights with respect to the panel  14 , depending on whether or not the vent seal upper wall  90  is being engaged by the vent grate  62 . A first height with respect to the upper surface  20  of the panel  14  is defined when the vent grate  62  is removed from the cooktop  10 . In such instance, the vent grate  62  does not engage the vent seal  80  and the upper wall outer segment  96  extends substantially horizontally, defining a constant height across its length. A second height with respect to the upper surface  20  of the panel  14  is defined when the vent grate  62  is mounted to the cooktop  10 . The second height is lower or shorter than the first height. In such instance, the second height is defined when the vent grate  62  engages the vent seal  80  so that part of the upper wall outer segment  96  is pushed down by the weight of the vent grate  62  as transmitted through the lower edges  76  of the vent grate side walls  68 . The weight of the vent grate  62  is great enough to substantially push the vent seal upper wall outer segment  96  toward the panel  14 . The extent to which the vent seal upper wall outer segment  96  is pushed down is limited or defined by the space between the lower edges  76  of the vent grate side walls  68  when the feet  70  are sitting upon the panel  14 , supporting the vent grate  62 . 
     Although the best mode contemplated by the inventors of carrying out the present invention is disclosed above, practice of the present invention is not limited thereto. It will be manifest that various additions, modifications, and rearrangements of the features of the present invention may be made without deviating from the spirit and scope of the underlying inventive concept. 
     Moreover, the individual components need not be formed in the disclosed shapes, or assembled in the disclosed configuration, but could be provided in virtually any shape and assembled in virtually any configuration. Furthermore, all the disclosed features of each disclosed embodiment can be combined with, or substituted for, the disclosed features of every other disclosed embodiment except where such features are mutually exclusive. 
     It is intended that the appended claims cover all such additions, modifications, and rearrangements. Expedient embodiments of the present invention are differentiated by the appended claims.