Abstract:
A ceiling mounted lighting fixture for insertion in a ceiling grid wherein the source of artificial light is a plurality of light emitting diodes.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to the artificial lighting field and more particularly to a ceiling mounted lighting fixture adapted to mount in a standard ceiling grid and utilizing LED as the source of the artificial lights. 
     2. Description of the Prior Art 
     Many types of lighting fixtures adapted to be mounted on ceilings of residential, commercial and industrial facilities have been utilized in the past. Such lighting fixtures have included hanging chandeliers, fixtures attached to the ceiling, track lights and the like. Incandescent bulbs or fluorescent bulbs have generally been utilized in such fixtures to provide the source of the artificial light. 
     Many ceilings in residential, commercial and industrial type buildings have included ceiling tiles of various materials and configurations. The tiles were generally arrayed in a standardized rectilinear matrix or grid often in a T bar grid having basic dimensions spaced to be a 24 inch by 24 inch grid. The tiles were supported on multiple interconnected T bar cross members, generally fabricated from metal, which had outwardly extending flanges for supporting the tiles. Lighting fixtures such a fluorescent bulb lighting fixtures were often fabricated in dimensions matching one or a multiple of the grid spacing, such as 24 inch by 24 inch, 48 inch by 24 inch or the like to replace one or more of the tiles thereby allowing installation of the fixture in the ceiling in any desired array within the grid and supported in part on the cross members. As a result, such fluorescent fixtures including the reflectors, casing and associated hardware necessary for operation were often bulky and costly to manufacture, store and ship. Additionally, while the fluorescent bulbs utilized less electrical energy than incandescent bulbs for equivalent light output, the demands for even greater conservation of energy have indicated that it is desirable to provide an artificial light output that utilizes even less energy than fluorescent bulbs for the same or nearly the same light output and that requires less space for mounting in a standard T bar grid array. Additionally, it is desired to provide a lighting system that requires less maintenance due to a longer lamp live and requiring less labor for installation. 
     Thus, there has been a need for compact artificial lighting fixture that is adaptable for installation as a standardized T bar ceiling grid without major modifications to the grid and that minimizes the amount of electrical energy utilized for light outputs equivalent to the light output of incandescent bulbs or fluorescent bulbs. 
     Accordingly, it is an object of the present invention to provide a compact source of artificial light output. 
     It is another object of the present invention to provide compact source of artificial light output that may be installed as a standardized T bar ceiling grid with minimum modifications to the grid. 
     It is another object of the present invention to provide a compact source of artificial light output that may be installed as a standardized T bar ceiling grid with minimum modifications to the grid and which minimizes the electrical energy utilized to produce the light output. 
     SUMMARY OF THE INVENTION 
     The above and other objects of the present invention are achieved, in a preferred embodiment thereof by providing a light fixture for providing artificial light. The light fixture has a generally hat shaped mounting bracket having a top portion, a pair of opposed side portions depending from the top portion and outwardly extending flange portions connected to the side portions and spaced from the top portion. The top portion has an inside surface which faces the area to be illuminated and an outside surface which faces into the area above the ceiling. 
     A plurality of light emitting diodes (LED) are connected in parallel and mounted on the inside surface of the top portion of the hat shaped bracket. The LED may be in a linear array or any other array as desired for particular applications. 
     One or more cooling fins are coupled to the outside surface of the top portion of the hat shaped bracket, or in some embodiments, from the side portions, and extend away therefrom to provide for heat dissipation from the operation of the LED&#39;s and/or for connection to additional supporting structure which may be required in some applications. 
     Conventional electrical wires and electrical connectors are provided to supply the electrical energy to the LED. Ceiling tiles may be supported on the outwardly extending flanges so that the lighting fixture of the present invention may be installed into either a T bar grid of a new ceiling construction or retrofitted into the T bar grid of old ceiling structures. A reflector member may be installed adjacent the inside surface of the top portion of the hat shaped mounting bracket to direct the light from the LED&#39;s toward the area to be illuminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The above and other embodiments of the present invention may be more fully understood from the following detailed description taken together with the accompanying drawing wherein similar reference characters refer to similar elements throughout and in which: 
         FIGS. 1 and 2  illustrate a conventional T bar grid cross member of the type forming a grid array into which the lighting fixture of the present invention may be installed; 
         FIG. 3  is a bottom perspective view of a lighting fixture according to the principles of the present invention; 
         FIG. 4  is an end view of a lighting fixture according to the principles of the present invention; 
         FIG. 5  is a side perspective view of a lighting fixture according to the principles of the present invention showing the installation in a ceiling grid; 
         FIG. 6  is front perspective view of a lighting fixture according to the principles of the present invention showing the installation in a ceiling grid; 
         FIG. 7  is a side view of a lighting fixture according to the principles of the present invention; 
         FIG. 8  is a partial sectional view of a ceiling grid looking up at the ceiling in which the lighting fixture of the present invention forms the complete ceiling grid; 
         FIG. 9  is a partial sectional view of a ceiling grid looking up at the ceiling in which the lighting fixture of the present invention forms a portion of the ceiling grid; 
         FIG. 10  is an end view of another embodiment of a mounting bracket useful in the practice of the present invention; 
         FIGS. 11 and 12  illustrate another embodiment of an LED lighting assembly according to the principles of the present invention; 
         FIG. 13  illustrates a schematic representation of circuit board useful in the practice of the present invention; 
         FIG. 14  is a perspective view of the mounting bracket of  FIG. 10  with the circuit board and LED lighting assembly omitted for clarity; 
         FIG. 15  illustrates the connection of a conventional ceiling mounting grid T-bar to a lighting fixture of the present invention; 
         FIG. 16  illustrates a clip useful in connecting together LED lighting fixtures of present invention; 
         FIG. 17  illustrates the clip of  FIG. 16  connecting together two lighting fixtures of the present invention in a linear array; 
         FIG. 18  illustrates the clip of  FIG. 16  connecting together two lighting fixtures of the present invention in a linear array and a clip in position to connect lighting fixtures of the present invention in a T configuration; 
         FIG. 19  illustrates the use of an end cap useful in the practice of the present invention; and, 
         FIG. 20  illustrates a modified hat shaped mounting bracket useful in the practice of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawing, there is illustrated in  FIGS. 1 and 2  a typical T bar grid support  10  of the type often used in ceiling grid arrays. The T bar grid support has an upright body member  12  and pair of side flanges  14 . A connector portion  16 , shown schematically in  FIG. 1  and in detail in  FIG. 15 , extend from each of the ends of the upright body member  12  and are used to insert into apertures such as aperture  18  in the upright body member  12  of adjacent T bar grid supports extending at right angles. The lower surface  14   a  of the side flanges  14  are visible from the area  20  of the room in which the T bar grid and ceiling is installed. The area  22  above the T bar may be an attic or other open space above the ceiling. Ceiling tiles  24  rest on the upper surface  14   b  of flanges  14 . The T bars such as T bar  14  are often aligned in a matrix or grid spaced in 12 inch spacing or multiples of 12 inch spacing. The upright body member  12  is often supplied with apertures  26  to which supporting members (not shown) may be attached for connection to structure (not shown) in the area  22 . 
     The present invention is adapted to be included in a T bar grid having T bars the same or similar to the T bar  10 . 
     Referring now to  FIGS. 3 to 7  there is illustrated an embodiment  30  of the present invention generally designated  31 . As shown thereon there is a hat shaped mounting bracket  32  having a top portion  34  with an inside surface  36  and an outside surface  38 . A pair of side portions  40  and  42  have an upper end  40   a  and  42   a  connected to the top portion  34  and depend from the top portion  34  to a bottom edge  40   b  and  42   b . The side portions  40  are in a first preselected width spaced relationship indicated by W on  FIG. 4 . The dimension W may be in the range of ⅛th inch to 3 inches though larger dimensions may be used for particular applications. The lighting fixture  32  may have a preselected longitudinal length L ( FIG. 5 ) of 12 inches though length L may be from, for example 2 to 144 inches, or longer if desired, depending upon the requirements of a particular application. 
     The side portions  40  and  42  extend a first preselected distance H from the top portion  34  as shown on  FIG. 4  and the first preselected distance H may be on the order of 2 inches though a larger or smaller distance may used as desired for particular applications. 
     A pair of flanges  44  and  46  are provided and flange  44  extends outwardly from the bottom end  40   b  of side portion  40  a second preselected distance indicated on  FIG. 4  by F. F may be on the order of ⅛th inch to 1 inch. Flange  46  extends the same distance F from the bottom end  42   b  of side portion  42  though in some applications the flanges  44  and  46  may extend outwardly different distances. Ceiling tiles  48  may rest on the flanges  44  and  46 , respectively. 
     A plurality of LED assemblies  50  are provided on a mounting block  52  that is coupled to the inside surface  36  of top portion  34  of the hat shaped mounting bracket  32 . In some embodiments of the present invention the LED assemblies may be mounted directly on the inside surface  36 , as shown on  FIG. 4  and the mounting block  32  eliminated. The mounting block  52  may, if desired have a reflective inner surface  52   a . Each of the LED assemblies has an LED  56  therein for emitting light indicated by the arrows  60  generally in the direction of the area  20 . Electrically conductive wires  58  connect each of the LED assemblies in parallel. 
     One or more cooling fins  70  are coupled to the outer surface  38  of the top portion  34  of the hat shaped mounting bracket  32 . In preferred embodiments of the present invention, the cooling fin  72 , which is centrally located on the top portion  34  of hat shaped mounting bracket  32  may be provided with apertures  74 . The apertures  74  may be utilized to allow connection of the lighting fixture  31  to supporting structure (not shown) in the area  22 . 
     In order to direct more light  60  into the desired area  20 , some embodiments of the present invention may be provided with a reflector  80  in the space between the inner wall surfaces  40   c  and  42   c  of the side portions  40  and  42  and the inner surface  36  of the top portion  34  of the hat shaped mounting bracket  32 . If desired, cooling fins  70   a  may be coupled to the side wall portions  40  and  42  to aid in the dissipation of heat into the area  22 . 
     Apertures  82  may be provided in side wall portions  40  and  42  to receive the connector portions  16  ( FIG. 1 ,  15 ) of conventional ceiling mounting grid T bar members in the grid in which the lighting fixture  31  is mounted. 
       FIG. 8  is a partial sectional view of a ceiling, generally designated  100 , looking upwardly at the ceiling. In the ceiling  100 , there are a plurality of lighting fixtures  102  according to the principles of the present invention arranged in a rectilinear array throughout the ceiling  100 . Ceiling tiles  104  rest on the flanges of the mounting bracket of the lighting fixtures  102 , as described above in connection with  FIG. 4  and below in greater detail in connection with  FIG. 10  The lighting fixtures  102  may be standard length corresponding to the length of the T bars or they may be shorter or longer. The tiles  104  may be cut to fit the spacing between the lighting fixtures  102  as required in particular applications. 
       FIG. 9  is a partial sectional view of a ceiling, generally designated  100 ′, looking upwardly at the ceiling. In the ceiling  100 ′, there are a plurality of lighting fixtures  102  according to the principles of the present invention arranged in a parallel linear array. As in the ceiling  100  of  FIG. 8 , conventional ceiling tiles  104  may rest on the T grid supports  106 . The lighting fixture of the present invention may be used in any ceiling in any spaced apart linear arrays so that light may be directed to any desired location. If other than a linear is required, the ceiling tiles  104  may be cut to match the array. 
       FIG. 10  is an end view of modified hat shaped mounting bracket similar to mounting bracket  32  described above useful in a LED lighting fixture of the present invention. As shown thereon, the mounting bracket  132  has a top portion  134  with an inside surface  136  and an outside surface  138 . A pair of side portions  140  and  142  have an upper end  140   a  and  142   a  connected to the top portion  134  and depend from the top portion  134  to a bottom edge  140   b  and  142   b . The side portions  140  and  142  are in a first preselected width spaced relationship indicated by W′ on  FIG. 10 . The dimension W′ may be in the range of ⅛th inch to 3 inches though larger dimensions may be used for particular applications. The side portions  140  and  142  extend a first preselected distance H′ from the top portion  134  as shown on  FIG. 10  and the first preselected distance H′ may be on the order of 2 inches though a larger or smaller distance may used as desired for particular applications. 
     A pair of flanges  144  and  146  are provided and flange  144  extends outwardly from the bottom end  140   b  of side portion  140  a second preselected distance indicated on  FIG. 10  by F′. F′ may be on the order of ⅛th inch to ½ inch. Flange  146  extends the same distance F′ from the bottom end  142   b  of side portion  142  though in some applications the flanges  144  and  146  may extend outwardly different distances. The flanges  144  and  146  extend the entire longitudinal length of the mounting bracket  134  in the preferred embodiments of the present invention. Ceiling tiles  148  may rest on the flanges  144  and  146 , respectively. 
     One or more cooling fins  170  are coupled to the outer surface  138  of the top portion  134  of the hat shaped mounting bracket  132 . As discussed below, in preferred embodiments of the present invention, the cooling fin  172 , which may be centrally located on the top portion  134  of hat shaped mounting bracket  132  may be provided with apertures  174  which may be utilized to allow connection of the lighting fixture  131  to supporting structure. 
     The hat shaped mounting bracket  132  is provided with top clip accepting shoulder member  182  and bottom clip accepting shoulder member  184  which extend longitudinally along the length of side portions  140  and  142  which, as discussed below, are utilized in conjunction with a clip to removably connect together adjacent hat shaped mounting brackets  132  in an aligned linear arrangement. Screw accepting members  186  also are coupled to each of the side members  140  and  142  and extend longitudinally along the length of the side members  140  and  142 . 
       FIGS. 11 and 12  illustrate another embodiment, generally designated  200 , of a LED lighting assembly  202  useful in the practice of the present invention. As shown on  FIGS. 11 and 12 , each of the LED&#39;s  204  are provided with a reflector  206  to direct the light emitted from the LED&#39;s into a selected light path. The reflectors  206  are shown on  FIGS. 11 and 12  as comprised of flat, planar members  206   a ,  206   b ,  206   c  and  206   d . The reflectors may be shaped of other geometric members as may be desired for particular applications to direct the light emitted from the LED&#39;s into any desired light path. 
       FIG. 13  is a semi-schematic perspective view of a circuit board  190  which contains the electrical connections for each of the LED&#39;s and the end terminals  190   a  for connection to and electrical power source. The circuit board  190  has an upper surface  192  which may be coupled to the inside surface  136  of hat shaped mounting bracket  132 . The coupling of the circuit board  192  to the inside surface  136  of hat shaped mounting bracket  132  may be by adhesives, screws, or any other desired coupling arrangement. The circuit board  190  also has a lower surface  194  to which a LED lighting assembly such as the LED lighting assembly  202  described above may be coupled with the connection tips  204   a  of LED&#39;s  204  projecting into the apertures  196  of the circuit board  190 . The assembly of the circuit board  190 , the lighting assembly  202  and the hat shaped mounting bracket comprise the LED lighting fixture  220  of the present invention. 
       FIG. 14  is a perspective view of the hat shaped mounting bracket  132  and in which the circuit board  190 , the LED lighting assembly  202  and ceiling tiles  148  have been omitted for clarity. Wires  210  or other similar materials provide a coupling configuration  212  and may be connected to the apertures  174  in cooling fin  172  and to such structure (not shown) thereabove in the volume  22  above as may be available to support the complete LED lighting fixture  220 . The side portions  140  and  142  of hat shaped mounting bracket  132  may be provided with apertures  222  for receiving the connecters of a T bar grid support such as the T bar grid support of  FIGS. 1 and 2 . 
       FIG. 16  illustrates a clip  250  useful in the practice of the present invention. As shown thereon there is a clip side member  252  and a clip top member  254  connected thereto and a clip bottom member  256  connected thereto. The clip top member  254  and the clip bottom member  256  extend outwardly from the clip side member  252 . The clip top member  254  has a clip top mating portion  258  and the clip bottom member  256  has a clip bottom mating portion  260 . The clip top mating portion  258  fits into the top clip accepting portion  182  of the hat shaped mounting bracket  132  and the clip bottom mating portion  260  fits into the bottom clip accepting portion  184  of the hat shaped mounting bracket  132 . 
       FIG. 17  shows a first LED lighting fixture  132 ′ and second LED lighting fixture  132 ″ connected together in an aligned linear array by a clip  250 . The clip  250  is connected to the top clip accepting member  182 ′ of the hat shaped mounting bracket  132 ′ and to the bottom clip accepting member  184 ′ of the hat shaped mounting bracket  132 ′ in regions adjacent the end  132 ′ a  of hat shaped mounting bracket  132 ′ as described above. In order to connect the two lighting fixtures  132 ′ and  132 ″ in aligned linear array such as, for example, the array shown on  FIG. 9 , the clip  250  is also connected to the top clip accepting member  182 ″ of the hat shaped mounting bracket  132 ″ and to the bottom clip accepting member  184 ″ of the hat shaped mounting bracket  132 ″ in regions adjacent the end  132 ″ a  of hat shaped mounting bracket  132 ″ a  as described above. The ends  132 ′ a  and  132 ″ a  abut each other as shown on  FIG. 17 . 
     In order to connect a LED lighting fixture of the present invention to, for example the end  132 ″ b  of lighting fixture  132 ″ shown on  FIG. 17 , and extending a right angles thereto as illustrated in  FIG. 8  the clip  250  may also be utilized.  FIG. 18  illustrates such a connection. As shown thereon, the LED lighting fixtures  132 ′ and  132 ″ are connected as shown on  FIG. 17 . The end  132 ″ b  of LED lighting fixture  132 ″ is connected to clip  250 ′ which extends transversely thereto. The connection between the clip  250 ′ and the LED lighting fixture  132 ″ is achieved by shown thereon, the LED lighting fixtures  132 ′ and  132 ″ are connected as shown on  FIG. 17 . The end  132 ″ b  of LED lighting fixture  132 ″ is connected to clip  250 ′ which extends transversely thereto. The connection between the clip  250 ′ and the LED lighting fixture  132 ″ is achieved by screws  280  extending through the side member  252  of clip  250  and into the screw accepting member  186 ″. As so coupled together, another LED lighting fixture (not shown) may be similarly connected to the clip  250 ′ in the directions indicated by the double ended arrow  300  to provide a connection of LED lighting fixtures as shown on  FIG. 8 . 
     In some applications of the present invention it may be desirable to cover the end, such as end  132 ′ b  of LED lighting fixture  132 ″.  FIG. 19  illustrates an end plate  302  coupled to the hat shaped mounting bracket  132  of a LED lighting fixture  320  according to the principles of the present invention. A pair of screws  280  extend through the end plate  302  and into the screw accepting aperture  186  of hat shaped mounting bracket  132 . 
     Referring now to  FIG. 20 , there is shown a slightly modified configuration, designated  132 ′, of the hat shaped mounting brackets  132  and  32  described above. As shown, the hat shaped mounting bracket  132 ′ has an inside surface  136 ′ of the top portion  134 ′. The corners  136 ′ a  and  136 ′ b , at the intersection with the side portions  140 ′ and  142 ′ are arcuate in shape rather than at right angles thereto as shown for hat shaped mounting brackets  32  and  132 . 
     Although specific embodiments of the present invention have been described above with reference to the various Figures of the drawing, it should be understood that such embodiments are by way of example only and merely illustrative of but a small number of the many possible specific embodiments which can represent applications of the principles of the present invention.