Abstract:
A deck system is made by joining deck units, each having a hat-shaped profile fastened to the topside of a profiled bottom panel. The bottom panel has nestable or interlocking side laps and one or more “dove-tail” shaped recesses formed therein. These recesses, which may be concave upward or downward, give the deck unit additional strength as a defined, confined location for use to run conduit and to provide vertical support for vertical loads. The deck system may be combined with a layer of concrete for use as a floor or roof.

Description:
PRIORITY CLAIM 
     Priority is claimed to U.S. provisional patent Ser. No. 61/296,620, filed Jan. 20, 2010, which is incorporated herein in its entirety by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     In construction, deck units are used to construct a deck system. A deck unit is comprised of one or more profiled forms made of steel that is handled as a single building component. Deck systems are simply a group of deck units that are fastened together in sufficient number to make the deck system of desired size. 
     The deck unit or deck system may support a layer of structural concrete in order to be used as a roof or floor, or a layer of lightweight insulating concrete in order to be used as a roof or may be used without the concrete. 
     Deck units include hat-shaped, profiled panels which are fastened to an exposed bottom panel to form closed cells within the deck units. The interiors of these cells may be used as air ducts, for running conduit for utilities and cabling, and to carry sound-absorbing materials. 
     Large open spaces, such as airport terminal areas and stadiums often have ceilings made of closed cellular deck systems. Often, these deck systems will also support hanging fixtures such as lighting, signs and sprinkler pipes. 
     There is a continual need for stronger deck systems that can span greater distances and have more capabilities while still possessing aesthetic qualities for public places. 
     SUMMARY OF THE INVENTION 
     The present invention is a deck unit comprising one or more top hat portions of various sizes and shapes joined to an exposed dove-tail bottom panel. The bottom panel includes at least one or more dovetail-shaped recess. A deck system is made by joining the present deck units. 
     Each deck unit includes a central hat-shaped panel with integral first and opposing second side laps of an attached bottom panel. The bottom panel is dimensioned to span the underside of one or more hat-shaped portions, and to have hidden side laps that nest with side laps of the hat-shaped portion. The deck units are fastened together to form the deck system. Importantly, the bottom panel has at least one “dove-tail”-shaped recess formed in it. These recesses, which may be concave upward or downward, provide additional strength to the deck unit and deck system, as well as a defined, confined recess in the bottom panel for use in concealing and running conduit and also in providing vertical support for lighting and other hanging type vertical loads when the present deck system is used as a roof/ceiling or floor/ceiling. 
     A feature of the present invention is the dove-tail shaped recesses formed in the bottom panel and throughout its length. The configuration of these dove-tailed panels and hat-shaped deck profiles together substantially increase stiffness to the deck system while providing the clean, plank-like appearance of the exposed underside of the deck system. Furthermore, the dove-tailed recesses provide additional capabilities to the deck system. Because the recess may be only partially closed, that is, it may have a narrow gap when viewed from below, it allows the deck system to support and conceal connections for exterior ceiling lighting and signage and aids in attenuating sound energy. 
     An advantage of the present system is that, from below, it has the appearance of planks, which especially in a large ceiling is aesthetically pleasing, while nonetheless providing functional spaces for acoustical materials and structural strength for the ceiling load over such long spans. 
     These and other features and their advantages will be readily apparent to those skilled in the art of metal deck system fabrication and construction from a careful reading of the Detailed Description of Preferred Embodiments, accompanied by the following drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the figures, 
         FIG. 1  is a top perspective view of a deck unit comprising two individual top hat profiles joined to a single exposed bottom panel, according to an embodiment of the present invention; 
         FIG. 2A  is a bottom perspective view of a deck unit including two individual top hat profiles joined to a bottom panel with concave upward and open dove-tail recesses, according to an embodiment of the present invention; 
         FIG. 2B  is a bottom perspective view of a deck unit including two individual top hat profiles joined to a bottom panel with concave downward and closed recesses, according to an alternative embodiment of the present invention; 
         FIG. 3  is a side view of a portion of deck system serving as a ceiling, with concrete placed above, in an embodiment of the present invention; and 
         FIG. 4  is a perspective, partially-cut-away view of the deck unit of  FIG. 1  with deck struts inside the first and second top hat profiles, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention is a deck unit including at least one top-hat profile attached to a bottom panel for use in making a deck unit for a roof or floor. The bottom panel includes at least one dovetail-shaped recess. Adding the top hat profile to the bottom panel with dovetail recesses substantially increases the strength of the deck unit. The present deck unit can be joined together to form a deck system, which can be used with or without a layer of concrete depending on specifications for the application of use. A deck unit with more than one top hat profile attached to one bottom panel makes assembling the deck system faster, and the present description of embodiments of the present invention and accompanying drawings will show plural top hat profiles in each deck unit. However, the present deck unit may alternatively have just one or more than two top hat profiles. 
     Referring now to the figures, there is shown in  FIGS. 1 ,  2 A and  2 B, top and bottom perspective views, respectively, of a deck unit  8 . Each deck unit  8  includes two top hat profiles  10  attached to one bottom panel  12  and has a distance end to end that runs the length of a specified span of a ceiling or roof. Deck unit  8  is handled as a single unit and combined with other deck units  8  to construct a deck system of the specified width. 
     Although deck unit  8  is shown as having two individual top hat-shaped profiles  10 , it may be made with one top hat profile  16 . Top hat profiles  16  are integrally joined and both may be formed from a single profiled sheet of metal, preferably steel. 
     Each top hat profile  16  includes a top flange  22  integrally formed with two side walls  24 ,  26 . Side walls  24 ,  26 , may be nearly at right angles to top flange  22 , but may be canted slightly outwardly from top to bottom as shown in the figures so as to be spaced slightly farther apart at the bottom of top hat profiles  16  and slightly closer together at top flange  22 . 
     Top flange  22  may have one or more grooves  30  formed therein, trapezoidal in shape with the bottom  32  of groove  30  being smaller than the opening at the top of the groove  30 , and side walls  36 ,  38  of groove  30  may be symmetrically flared outwardly in the upward direction. A groove  30  adds stiffening to top hat profile  16   
     Each top hat profile  16  has bottom flanges  42 ,  44 , and each of them may have a bead  46 ,  48 , formed therein to add stiffening. Deck unit  8  is formed by securing top hat profiles  10  on bottom panel  12 . Each bottom flange  42 ,  44  of each top hat profile  16  of deck unit  8  is connected integrally to bottom panel  12  by a mechanical fastening process, such as by welding for example. 
     Bottom panel  12  is also preferably a profiled sheet of metal, such as steel, that covers the bottom openings of top hat profiles  10  of a deck unit  8  to define spaces or cells  50  therebetween. Bottom panel  12  also provides side laps  52 ,  54 , for fastening adjacent deck units  8  together. Side laps  52 ,  54  are formed so that a side lap  52  of one bottom panel  12  nests within or interlocks with a side lap  54  of an adjacent bottom panel  12 . By the term nesting, it is meant that the length of one side lap  52  fits within and follows closely with the length of the other side lap  54 , that the contours of one side lap  52  follow closely in the same directions and has the same changes in direction as the contours of the other side lap  54 . By the term interlocking, it is meant that a portion of one side lap  52 , is crimped to the other side lap  54  so that the materials of which the two side laps  52 ,  54 , are made penetrates each others boundaries. 
     Bottom panel  12  may be perforated so as to have an array of holes  58  formed therein for absorbing sounds (see  FIGS. 2A and 2B ) into cells  50 . 
     Bottom panel  12  has at least one, and preferably more than one, dove-tail shaped recesses  60  formed therein, and may have two dovetail recesses  60  for each top hat profile  16  of deck unit  8  in registration with each cell  50 . Recesses  60  may be concave upward or concave downward. Recesses are concave upward when viewed from below bottom panel  12  as they extend into cells  50 , as shown in  FIG. 2A . Dovetail recesses  60  have narrow openings  64  and may extend concave downward, to the exterior of cell  50  below bottom panel  12  expanding in the downward direction, as shown in  FIG. 2B . 
     Bottom panel  12  at dove-tail recesses  60  provide a nearly-closed, well-defined, protected conduit for piping, wiring, cables, optic fibers or sound insulating material  62  ( FIGS. 2A and 2B ). Bottom panel  12  at recesses  60  may be used to support vertical loads from below bottom panel  12 , such as signage  68  and lighting  70  (see  FIG. 3 ). 
       FIG. 3  illustrates a deck system  72  formed of at least two deck units  74 , each defined by two top hat profiles  76  with a dovetail bottom panel  78 . As illustrated in  FIG. 3 , a layer of concrete  80  overlays deck system  72  when deck system  72  is to function as a composite roof or floor. 
     In addition, employing bottom panels  12  with dove-tail recesses  60  attached to a top hat profile adds significantly to the strength of deck system  72  and allows for longer spans as well as greater functionality. Recesses  60  may be open and concave upward as illustrated in  FIGS. 2A and 3  or closed and concave downward, as illustrated in  FIG. 2B . If concave upward, the top of the dove-tail recesses may be used as added support for metal deck struts  90 , as disclosed in application Ser. No. 11/347,484 filed Feb. 3, 2006 for a metal deck strut system, as seen in  FIG. 4 , which is identical to  FIG. 1  except for the addition of struts  90 . 
     The superior strength of the present invention over an otherwise similar bottom panel with dove-tail recesses alone, is illustrated by the following example. Assuming a uniform load of 30 pounds per square foot and using 20 gauge steel, the span limit of a dovetailed panel is 12.5 feet. With a 20 gauge steel top hat profile attached to the dove-tailed panel, the span limit for the same loading increases to 20.5 to 26.5 feet depending on the height of the hat profile. 
     In addition to its great strength, the present invention also adds to the functional aesthetics of a ceiling of a building covering a large area, such as an airport terminal or an arena. The concave upward dovetail recesses establish narrow gaps in the otherwise smooth panel liners to create a plank look from below. This plank look gives the viewer a better indication of the perspective of the area as well as provides an aesthetically-pleasing, clean-looking treatment to the ceiling. Concave downward dovetail recesses provide wider gaps which provide a similar visual effect. In both cases (concave upward and concave downward dove-tail recesses) the bottom panel also hides the sidelap connections between adjacent deck units. 
     Dove-tail recesses also provide a convenient way to suspend lighting fixtures and signage, to serve as a hidden chase way for electrical or plumbing purposes, and as a sound-absorbing chamber or place for inserting acoustic materials for absorbing sounds from below. 
     Those familiar with steel deck system construction will appreciate that many modifications and substitutions can be made to the foregoing preferred embodiments of the present invention without departing from the spirit and scope of the present invention, defined by the appended claims.