Abstract:
A rectangular ceiling tile proportioned for use in a standard rectangular ceiling grid module formed by grid tees, the tile having a pair of conductors arranged to feed low voltage electrical power from the grid elements to an electric or electronic device carried on the tile, the conductors each extending to an edge or edges of the tile and adapted to make physical contact with a conductor carried on a grid element when supported on such grid element.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This application claims the priority of U.S. Provisional Application No. 61/118,075, filed Nov. 26, 2008. 
         [0002]    The invention relates to suspended ceiling structures and, in particular, to electrification of such ceiling structures. 
     
    
     PRIOR ART 
       [0003]    Commercial building spaces such as offices, laboratories, light manufacturing facilities, health facilities, meeting and banquet hall facilities, educational facilities, common areas in hotels, apartments, retirement homes, retail stores, restaurants and the like are commonly constructed with suspended ceilings. These suspended ceiling installations are ubiquitous, owing to their many recognized benefits. Such ceilings ordinarily comprise a rectangular open grid suspended by wire from a superstructure and tile or panels carried by the grid and enclosing the open spaces between the grid elements. The most common form of grid elements has an inverted T-shaped cross-section. The T-shape often includes a hollow bulb at the top of the inverted stem of the T-shape. A popular variant of this standard T-shape includes a downwardly open C-shaped channel formed by the lower part of the inverted tee. 
         [0004]    Advances in electronics has fed further advances and lead the world into the digital age. This digital movement creates an ever-increasing demand for low voltage direct current (DC) electrical power. This demand would seem to be at least as great in finished commercial space as any other occupied environment. A conventional suspended ceiling has potential to be an ideal structure for distributing low voltage electrical power in finished spaced. Many relatively low power devices are now supported on such ceilings and newer electronic devices and appliances are continuously being developed and adopted for mounting on ceilings. 
         [0005]    The ceiling structure, of course, typically overlies the entire floor space of an occupiable area. This allows the ceiling to support electronic devices where they are needed in the occupied space. Buildings are becoming more intelligent in energy management of space conditioning, lighting, noise control, security, and other applications. The appliances that provide these features including sensors, actuators, transducers, speakers, cameras, recorders, in general, all utilize low voltage DC power. 
         [0006]    As the use of electronics grows, the consumption of low voltage electrical power likewise grows. This seemingly ever accelerating appetite for DC power presents opportunities for more efficient transformation of relatively high voltage utility power typically found at 110/115 or 220/240 alternating current (AC) volts with which the typical enclosed space is provided. Individual power supplies located at the site of or integrated in an electronic device, the most frequent arrangements today, are often quite inefficient in transforming the relatively high voltage AC utility power to a lower DC voltage required by an electronic device. Typically, they can consume appreciable electric power in a standby mode when the associated electronic device is shut off. It is envisioned that a single DC power source serving the electronic needs of a building or a single floor of a building can be designed to be inherently more efficient since its cost is distributed over all of the devices it serves and because it can take advantage of load averaging strategies. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention provides accessories and components useful with and adapted to be carried on electrified suspended ceiling gird. In accordance with the invention, ceiling panels or tiles are arranged with conductive circuits that transmit electrical power from that carried on a supporting grid system. In some arrangements, the electrical circuit includes a connector that automatically makes electrical contact with the grid circuitry when the panel or tile is put in place on the grid. In accordance with other aspects of the invention, specialty border elements used in suspended ceiling islands distribute electrical power to the grid on which it is assembled and to electrical devices carried on the grid. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic fragmentary exploded isometric view of a suspended ceiling grid and a ceiling panel embodying the invention; 
           [0009]      FIG. 2  is a schematic isometric cross-sectional elevational view of the suspended ceiling system illustrated in  FIG. 1 ; 
           [0010]      FIG. 3  is a fragmentary cross-sectional isometric view of a modified form of a grid tee and ceiling panel; 
           [0011]      FIG. 4  is a fragmentary cross-sectional isometric view of another modified grid tee and panel; 
           [0012]      FIG. 5  is a fragmentary cross-sectional isometric view of a slotted grid tee and pan type ceiling tile; 
           [0013]      FIG. 6  is a schematic isometric cross-sectional elevational view of a grid tee and ceiling panel with a variant manner of connecting an electronic device to the grid tee; 
           [0014]      FIG. 7  is a schematic isometric cross-sectional elevational view of a grid tee and ceiling panel having respective electrical conductors and a connector for receiving power from a grid in accordance with the invention; 
           [0015]      FIG. 8  is a schematic perspective view of a suspended ceiling having a decorative ceiling tile; 
           [0016]      FIG. 9  is a schematic plan view of a suspended ceiling island; and 
           [0017]      FIG. 10  is a fragmentary, schematic isometric cross-sectional view taken in the plane  10 - 10  indicated in  FIG. 9  showing constructional details of the perimeter of the island ceiling. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Referring now to  FIGS. 1 and 2 , a suspended ceiling grid  10  having main tees  11  and cross tees  12  of generally conventional cross-section is electrified by the provision of electrically conductive strips  13  running lengthwise on selected ones or all of the tees  11 ,  12 . The conductive strips  13  normally are electrically isolated from the tees  11 ,  12 , where the tees are formed of steel, aluminum or other conductive material, as is typical. The conductive strips  13  disclosed in the various figures can be a conductive ink, or a suitable metal foil or tape or wire of copper or aluminum, for example. Where the tees are electrically conductive themselves, they can serve as a conductive strip providing that they are suitably electrically insulated from appropriate other tees. 
         [0019]    A ceiling panel  14  of suitable material, known in the industry, having physical stability, fire resistance and, preferably, acoustic properties, is illustrated at  14 . In plan view, the panel  14  is rectangular, being square and having nominal dimension of 2′×2′ or metric equivalent, for example, or being somewhat elongated normally at 2′×4′ or metric equivalent, for example. The panel  14  has an electric or electronic device  16  mounted thereon. The device  16  can be a light fixture using light emitting diodes (LEDs), a speaker, a sensor for building control, security, or other function, a wireless support device, a camera, or other known device or apparatus having modest or limited electrical power consumption. 
         [0020]    On its upper side, the ceiling panel  14  has two separate electrical conductors  17 ,  18 . The conductors  17 ,  18  can have the same or like construction as that described for the strips  13 . In the arrangement of  FIGS. 1 and 2 , as well as certain other figures, the conductors  17 ,  18  run from the electronic device in opposite directions so that they draw current between the grid tee conductive strips  13  at opposite polarities on separate grid tees. Those skilled n the art, however, will understand that multiple conductive strips  13  can be provided on a single tee  11  or  12  and a ceiling panel can have its conductors  17 ,  18  in a parallel arrangement such that they are connected to these separate conductors  13 , on a common tee. Moreover, a ceiling panel can be arranged with its electrical conductors  17 ,  18  to connect to conductive strips on the tees  11 ,  12  where such tees are perpendicular to one another. 
         [0021]    At the end of each of the conductors  17 ,  18 , a flexible conductive leaf  19  is fixed to an edge of the panel  14 . The leaf  19 , which is in electrical continuity with an associated conductive strip  17  or  18 , serves as a contact to establish an electrical circuit with the adjacent conductive strip  13  on the tee  11 , or  12 , supporting the respective edge of the panel  14 . The leaf  19  is configured to automatically make contact with a conductive strip  13  when the panel  14  is in position on the grid  10 . Additionally, the leaf  19  is configured to allow the panel  14  to have a limited degree of lateral freedom to accommodate normal dimensional variations in the grid  10  and panel  14  as well as permitting the panel to be lifted from below the ceiling to gain access to the plenum above the plane of the ceiling. 
         [0022]    Referring now to  FIG. 3 , a tee,  11  or  12 , carries a conductive strip  13  on the upper side of its lower flange. A ceiling panel  14  has an electrical contact  21  formed by a strip of electrically conductive material which is in electrical continuity with the respective electrical conductor  17  or  18 . Alternatively, the contact  21  can be an extension of the respective conductor  17  or  18 , that is wrapped along the vertical edge of the ceiling panel  14  and brought under a limited portion of the front or lower face of the panel. The contact  21  is fixed to the panel  14  with a suitable adhesive or other expedient. 
         [0023]    With reference to  FIG. 4 , the tees  11  and  12  have their conductor strips  13  positioned on their vertical webs  26 . A leaf spring  27  attached to the edge of the panel makes electrical contact with a conductor strip  13 . The leaf spring is electrically continuous with an associated conductor  17  or  18 . As before, a panel  14  is provided with two leaf spring contacts  27  to account for the opposite polarities. 
         [0024]    With reference to  FIG. 5 , there is shown a generally conventional style grid tee  31  of the open channel or slotted type. A pan-like ceiling tile  32  of known construction formed of sheet metal such as aluminum has an upstanding skirt or flange that snaps over inwardly bent edges  34  of the tee  31 . The tile  32  is retained on the tee by a grip of its flange  33  on the tee edges  34 . The tile is removable downwardly from the grid tees  31  to provide access to the plenum above the plane of the ceiling. A conductive strip  13  is provided on the vertical side  36  of the tile supporting flange of the grid tee. A conductive leaf spring  37  of copper or brass or like material is fixed to an upper side of the pan  32  in a manner that isolates it electrically from the pan. The leaf spring conductor  37  is electrically connected to an associated conductor  17 ,  18  which as in earlier embodiments, are operably connected to the electronic device  16  carried by the tile or panel  32 . The conductors  17 ,  18  are electrically insulated from the pan  32 . As an alternative arrangement, the body of the grid tees can be one polarity and the conductive strip  13  can be of the opposite polarity. In this circumstance, the pan can be at the same polarity as the grid tees  31  and only one leaf spring  37  and conductor strip  17  need be used. One electrical side of the device  16  is connected to the strip and the other electrical side of the device is connected to the pan or tile  32 . 
         [0025]    In  FIG. 6 , the grid tee is provided with a pair of conductive strips  13  on opposite sides of its reinforcing bulb designated  41 . A C-shaped or channel-shaped connector bracket  42  is assembled over the reinforcing bulb  41 . The bracket  42  has a pair of individual contacts  43 ,  44 , one on each side of the bulb  41 . The contacts  43 ,  44  establish electrical communication between the conductive strips  13  and a two-wire or two-conductor lead  46 . The lead  46  carries the voltage potential existing across the conductive strips  13  to an electronic device  16  on the panel  14 . 
         [0026]    Referring to  FIG. 7 , the ceiling panel  14  has a pair of conductors  15 . The conductors  15  are rolled or bent vertically down the vertical face  51  of the panel edge. A connector  52  molded or otherwise formed of a suitable electrically insulating material such as PVC carries two separate conductors  53 ,  54 . The conductors  53 ,  54  can be made of spring-like conductive metal such as copper or brass and can be insert-molded in the connector  52 , for example. Each conductor  53 ,  54  makes exclusive contact with one of the conductive strips  13  carried on opposite sides of the reinforcing bulb  41 . Conductive strips  17 ,  18  on the panel  14  are each connected to one of the conductive strips  13  on the tee  11 . 
         [0027]    In the various disclosed embodiments of the invention, the conductive strips  13 ,  17  and  18  have their outer or exposed surfaces un-insulated to facilitate electrical connections with the various connecting elements. Alternatively, the conductors can be fully insulated except on points at which an electrical connection is to be made where such insulation can be omitted or removed. 
         [0028]    Referring to  FIG. 8 , there is shown a suspended ceiling system in which the ceiling panel  61  has a decorative feature in the form of a cut-out in the shape of a star  62 . The electronic or electrical device  16  in this arrangement can be an LED or series of LEDs on the upper side of the ceiling panel  61  and arranged to shine through the cut-out. The electronic device can be powered through conductive strips  17 ,  18  which in turn are electrically connected to conductive strips  13  on the grid tees  11  and  12  as described in the various preceding embodiments. 
         [0029]    Referring now to  FIGS. 9 and 10 , a suspended island ceiling  66  generally known in the art includes main tees  11  and cross tees  12 . The tees  11 ,  12  are bordered by a perimeter trim  67  which can be, for example, an aluminum extrusion having a general shape of a right triangle. The perimeter trim  67  has a low profile when viewed from below owing to a “knife” edge  68  and a low rise of a vertical leg  69 . Parallel longitudinal formations  71  are undercut to retain splice plates (not shown) or trim attachment clips  72  used to mount the trim  67  to the ends of the tees  11 ,  12 . Conductive strips  76  analogous to the conductive strips  13  are provided along the lengths of the trim  67 . The conductive strips  76  are conveniently located along the forms  71 , as shown. The perimeter trim mounted conductive strips  76  can serve to electrify the grid  10  that is confined to the island ceiling  66 .  FIG. 10  illustrates an exemplary manner in which electrical power is transmitted to the tees  11  or  12 . The conductive strips  13  on the tees  11  and  12  are situated on the upper surfaces of the grid tee flanges. The vertical leg  69  of the perimeter trim  67  is apertured at the intersection of a grid tee  11 ,  12 . This may be accomplished by drilling holes in the leg  69  on site when the island is being erected. Electrical jumpers  78  can be assembled through the holes  77 . At one end, a jumper  78  makes contact with the respective conductive strip  76  on the trim  67  and at its other end makes contact with a conductive strip  13  on the tee  11 ,  12 . The jumpers  78  are suitably electrically insulated with insulating material so as to not short out where it may contact the perimeter trim  67 . Where desired, the trim  67  can be held at one polarity and the tees  11 ,  12  can be electrically connected to the trim. In this case, only one conductive strip  76  is needed. 
         [0030]    While the invention has been shown and described with respect to particular embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art all within the intended spirit and scope of the invention. Accordingly, the patent is not to be limited in scope and effect to the specific embodiments herein shown and described nor in any other way that is inconsistent with the extent to which the progress in the art has been advanced by the invention.