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RELATED APPLICATIONS AND PATENTS 
     Priority is claimed to U.S. Provisional patent application Ser. No. 61/414,955, filed Nov. 18, 2010, which is incorporated herein in its entirety by reference. US non-provisional patent application Ser. No. 11/347,484 filed Feb. 3, 2006 and Ser. No. 12/856,033 filed Aug. 13, 2010 are related to the present application and are hereby incorporated in their entirety by reference. 
    
    
     SUMMARY OF THE INVENTION 
     Steel deck systems are used in commercial buildings as ceilings because they are both strong and aesthetically pleasing in their long, clean lines. A deck system is made of deck units placed in side-by-side arrangement and joined together in sufficient numbers to form the deck system of the desired size. A layer of concrete or steel may be placed on the deck system for added strength. Each deck unit may be cellular or non-cellular. Cellular deck units define an enclosed space which may be used to conceal conduit, wiring, optic fibers, and piping. Non-cellular deck units may be used where conduit, wiring, optic fibers and piping do not require concealment. Perforated cellular units are closed with a cover panel that is perforated and which units may house sound insulation particularly in the case of deck units that are used in airport terminals or other areas where noise levels are generally higher. 
     The present invention is an openable, hinged cover panel for deck units that are used as part of a ceiling&#39;s deck system. The hinges and latches of the cover panel are obscured from view from below and the cover extends the full length of the deck unit so that the clean lines of the deck system are preserved. 
     These and other features and their advantages will be readily apparent to those skilled in the art of deck systems 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 an end perspective view of a first profile of a deck unit, according to an embodiment of the present invention. 
         FIG. 2  is an end view of the profile of the deck unit of  FIG. 1  with the cover panel opened, according to an embodiment of the present invention. 
         FIG. 3  is a view of a detail of the deck unit of  FIG. 1  showing the cover panel U-nut bracket, according to an embodiment of the present invention. 
         FIG. 4  is a view of a detail of the deck unit of  FIG. 1 , showing the hinge according to an embodiment of the present invention. 
         FIG. 5  is an end perspective view of a second profile of a deck unit, according to an embodiment of the present invention. 
         FIG. 6  is an end view of the profile of the deck unit of  FIG. 5  with the cover panel opened, according to an embodiment of the present invention. 
         FIG. 7  is an end perspective view of a third profile of a deck unit, according to an embodiment of the present invention. 
         FIGS. 8 and 9  are end views of profiles of the deck unit of  FIG. 7  with the cover panel opened and, in  FIG. 8 , full covering layers of steel and concrete added, and, in  FIG. 9 , a partial layer of steel and a full and penetrating layer of concrete added, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The present invention is a deck system for use as a ceiling for a floor or roof. The present deck system may include a layer of concrete or metal plates or other materials applied on top of it depending on its application and whether it is used as a floor or roof. 
     The present deck system is composed of individual deck units and are generally indicated by reference number  10  in  FIGS. 1 and 2 .  FIGS. 3 and 4  are detailed drawings of the hinge and latch mechanism of the present deck unit  10  that may be used with any of the three embodiments shown, as well as others.  FIGS. 5 and 6  illustrate a second deck unit with a recessed cover panel.  FIGS. 7 and 8  illustrate a third deck profile with a cover panel. However, the principles described herein apply in a straight-forward manner to these and other types of deck unit profiles. 
     Deck unit  10  is made of sheet metal, preferably sheet steel, and formed to have a profile, such as that shown in  FIGS. 1 and 2 , that is, when viewed from the end, the sheet metal is formed to have the general shape shown in  FIGS. 1 and 2  along its full length, (and, alternatively, the shape of the profiles shown in  FIGS. 5 and 6 , and  FIGS. 7 and 8 , or other similar profiles) and to be as long as needed to span the gap between supports provided for each end of each deck unit  10  of the deck system to which it belongs. 
     Deck unit  10  has a top flange  12 , two opposing, spaced-apart side walls, namely, first side wall  14  and second side wall  16 , with a first side flange  18  and a second side flange  20  extending laterally from first and second side walls  14 ,  16 , respectively. First side flange  18  has a first side lap  22  and second side flange  20  has a second side lap  24 . First and second side laps  22 ,  24 , which extend generally perpendicular to first and second side flanges  18 ,  20 , are used for joining deck unit  10  to adjacent deck units  10 . 
     First side wall  14 , second side wall  16  and top flange  12  define an interior space  26  that is open from below. Top flange  12 , first and second side walls  14 ,  16 , first and second side flanges  18 ,  20 , and first and second side laps  22 ,  24  may be integrally connected, meaning they are formed by bending or drawing one sheet of metal to have the profile shown in  FIGS. 1 and 2 . A first side flange  18  from one deck unit  10  will be placed in adjacent relationship with a side flange  20  of an adjacent deck unit  10 , to be fastened together, and to others and so on, adding and fastening additional deck units  10  to form a deck system as wide as desired and as long as each deck unit  10  in order to construct a complete deck system. Side laps  22 ,  24 , of deck units  10  may be fastened together by welding or crimping or by use of screws or a combination of such techniques. 
     A cover panel  28  spans interior space  26  and may run from first side wall  14  to second side wall  20  or may extend to the lateral-most edges of deck unit  10 , preferably with a slight radius at the extreme ends of first side flange  18  and second side flange  20  as shown. Cover panel  28  is attached to profile  10  using a hinge  30 , thereby closing interior space  26  to be enclosed from below. Hinge  30  permits cover panel  28  to pivot between a closed position wherein cover panel  28  encloses interior space  26  and an open position wherein cover panel  28  swings away from interior space  26 . 
     Cover panel may have a plurality of perforations or through holes  32  that arranged in an array if desired. Holes  32  admit sound waves into interior space  26  where they may be absorbed by, for example, a sound absorbing material (not shown in  FIGS. 1 and 2 ) inside deck unit  10 . Deck unit  10  may also have plural spaced-apart struts  36  in interior space  26 , running from first side wall  14  to second side wall  16 , both to add stiffness and for other uses of interior space  26 , such as to provide support for electrical, communication, safety, security and plumbing lines (not shown) in interior space  26 . 
     Hinge  30  may be a full length hinge, such as a continuous hinge, or it may be a series of hinges aligned over the length of deck unit  10 . As best seen in  FIG. 4 , hinge  30  has two leaves, namely, a first leaf  38  and a second leaf  40  pivotally connected by a hinge pin  42 . As shown in  FIGS. 1 and 2 , first leaf  38  may be attached to first side lap  22  and second leaf  40  may be attached to cover panel  28 . First and second leaves  38 ,  40 , may be attached to first side lap  22  and cover panel  28 , respectively, using screws, bolts, weldments, adhesives or other convenient means. Hinge  30  should be selected and positioned so that its knuckles  66  are just below and just inside of second leaf  40  so that, when one deck unit  10  is placed next to an adjacent deck unit  10 , second leaf  40  is between them but, other than a thin gap between deck units  10 , first leaf  38  and knuckles  66  are not visible from below. 
     As best seen in  FIG. 3 , inside interior space  26 , defined by top flange  12  and spaced-apart first and second side walls  14 ,  16 , is a U-nut bracket  48  attached to first side wall  14  as part of the latch of deck unit  10 . U-nut bracket  48  may be attached to first side wall  14  using screws  56  or, alternatively, weldments, adhesives, or bolts, as convenient. U-nut bracket  48  includes an elongated hole  50  formed therein. A U-Nut  52  is engaged with U-nut bracket  48  to place a threaded hole  54  in U-nut  52  in registration with the elongated hole  50  of U-nut bracket  48 . Elongated hole  50  is elongated parallel to the major dimension of deck unit  10 . Elongated hole  50  thus allows a modicum of tolerance parallel to the long dimension of deck unit  10  in the exact location of U-nut  54  with respect to U-nut bracket  48 . 
     U-nut bracket  48  may be attached to first side wall  14  by screws  56 , as shown, or by bolts or by welding, as convenient. To enable cover panel  28  to be secured in the closed position, a nut  58  is attached to cover panel  28 , preferably to inner surface of cover panel  28  over a hole  32  in cover panel so that hole  32  is aligned with the threaded hole  60  in nut  58 , the threaded hole  54  in U-nut  52  and elongated hole  50  of U-nut bracket  48 . A hex socket set screw  62  may then be passed through hole  32 , threaded hole  60  of nut  58 , through U-nut  52  and elongated hole  50  of U-nut bracket  48 . Set screw  62 , preferably made of a dark metal or painted or coated with a dark color, can be readily found by a worker when close to cover panel  28  but cannot be as easily seen from the floor below after set screw  62  has been rotated just far enough through hole  32  to be approximately flush with the outside surface of cover panel  28 . 
     Cover panel  28  may have beads  68  formed therein to provide stiffness, but, from below, continuous hinge  30  and set screw  62  are not visible so the fact that cover panel  28  is a hinged access to interior space  26  not readily apparent, and the clean lines of deck units  10  joined as a deck system are preserved. 
     In use, a worker is elevated to deck unit  10  near holes  32  in cover panel  28  to look for the hole  32  where set screw  62  is located. Using a hex head wrench of suitable size, the worker backs set screw  62  out of hole  32  until the distal end of set screw  62  clears U-nut  52 . This process is repeated at intervals along the length of deck unit  10  for each set screw  62 . At that point, when all set screws  62  of that deck unit  10  have been released, cover panel  28  can be pivoted about continuous hinge  30  to its fully opened position to reveal interior space  26  of deck unit  10  for servicing or installing conduit, piping, wiring, optic cables, light fixture brackets and other utilities, as desired. Once servicing, maintenance or installation has been completed, access cover  28  is rotated back to its fully closed position and set screws  62  are advanced further through nut  58  and into U-nut  52  to secure access cover panel  28  to U-nut bracket  48 . 
     Referring now to  FIGS. 5 and 6 , there is illustrated a second embodiment of the present invention, a deck unit  80  having a cover panel  82  to enclose an interior space  84  and recessed therein. Deck unit  80  includes top flange  86 , each having a first side wall  88  and an opposing second side wall  90  to partially define interior space  84 . First side wall  88  has a lateral first side flange  92  and a second side wall  90  is attached to a lateral second side flange  94 . First side flange  92  includes a first side lap  96  extending generally perpendicular to it; second side flange has a corresponding second side lap  98 . First and second side laps  96 ,  98 , are used to join together adjacent deck units  80 . Decking unit  80  is formed from a single sheet of metal, preferably steel. 
     Cover panel  82  is attached to deck unit  80  in a manner similar to the way cover panel  28  is joined to deck unit  10 , namely with a hinge  102  having a first leaf  104  and a second leaf  106  that pivot with respect to each other about pivot pin  108 . First leaf  104 , however, is attached to second side wall  90  of deck unit  80  rather than to second side lap  24  of deck unit  10 . Second leaf  106  is attached to cover panel  82 . 
     Cover panel  82  includes a latch  110  similar to that illustrated in  FIG. 3 . 
       FIGS. 7 and 8  illustrate the present invention in a reentrant-type deck unit  120 , which includes plural top flanges  122 , plural bottom flanges  124 , and first and second side walls  126 ,  126 ′, connecting top flanges  122  to bottom flanges  124 , respectively.  FIG. 8  illustrates deck unit  120  with a sheet of steel  128  attached to deck unit  120  and a layer of concrete  130  on top flanges  122 . Steel  128  may carry embossments.  FIG. 9  is similar to  FIG. 8  except that the attached sheet of steel  128 ′ extends only over the hinged cell portion of deck unit  120 . In  FIG. 9 , a cap or hat  129  running the full length of deck unit  120  covers sound insulation  140  in the non-hinged portion of deck unit  120  to protect it from the inflowing of the concrete layer that compositely interacts with deck unit  120 . 
     A cover panel  132  runs from the bottom edges of first and second side walls  126 ,  126 ′, to enclose the interior space  134  above it and allow that space to contain, for example, conduit  136  supported on struts  138  (one shown) and sound insulation  140  below struts  138 . Sound insulation  140  may also be installed in other interior spaces  142  of deck unit  120  above bottom flanges  124  of deck unit  120 . Cover panel  132  and bottom flanges  124  may be perforated to pass sound waves into interior spaces  134  and  142  for absorption by sound insulation  140 . 
     Cover panel  132  is attached to wall  126  by a hinge  144 . Hinge  144  has a first leaf  146  and a second leaf  148  pivotally attached to first leaf  146  by a pivot pin  150 . First leaf  146  is attached to cover panel  132  and second leaf  148  is attached to wall  126 . Cover panel  132  swings from an open position to a closed position where it may be secured by a latch  152  similar to that shown in  FIG. 3 . 
     The present invention preserves the clean lines of a traditional deck system while allowing ready access to the utilities the deck units of that deck system is carrying when and as needed. 
     Those skilled in the art of metal deck systems will appreciate that substitutions and modifications can be made to the foregoing embodiments without departing from the spirit and scope of the present invention, which is defined by the appended claims.

Summary:
A deck unit has a hinged, cover panel for use in a deck system as a ceiling. The hinge may be a continuous hinge running the length of the deck unit, preferably a continuous hinge, and extend the length and width of the deck unit including its side flanges or be recessed within it. The edge of access panel cover opposite its hinge is secured using a securing mechanism to a bracket affixed inside the deck unit. By example, a set screw is threaded through a hole in the cover panel, through a weld nut on the inside face of the cover panel and through a U-nut straddling the bracket. Accordingly from a distance, the hinge, latch and the securing mechanism are not visible to indicate that the cover can be opened to permit access to the deck system interior.