Abstract:
A troffer door assembly includes a frame assembly having a plurality of interconnected frame members, a lens member retained by at least one of the plurality of interconnected frame members, a connecting member coupled to the frame assembly and configured to detachably couple the troffer door assembly to a housing of a troffer light fixture, a rigid brace member, and a plurality of LEDs attached to the rigid brace member. The rigid brace member includes a heat conductive material configured to dissipate heat produced by the plurality of LEDs. At least two of the plurality of interconnected frame members include a heat conductive material, and the rigid brace member is thermally coupled with the at least two of the plurality of interconnected frame members such that both the rigid brace member and the frame assembly dissipate heat produced by the plurality of LEDs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 14/452,137, filed Aug. 5, 2014, which is a continuation of U.S. application Ser. No. 13/414,032, filed Mar. 7, 2012, now U.S. Pat. No. 8,888,313, all of which are incorporated herein by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    The invention relates generally to troffer light fixtures, more particularly to troffer light fixtures having a removable hinged door or a removable hinged louver, and even more particularly to replacement doors or louvers for retrofitting troffer light fixtures, doors and louvers that are already installed. 
         [0003]    A troffer light fixture is a generally rectangular or square tray-like housing comprising a top body wall and four shorter side walls that is installed in or on a ceiling in an inverted manner such that it is open toward the floor. Electrical components, ballast, hardware and the like are affixed to the top body wall and/or the side walls. These components operate the light producing elements, typically one or more elongated or U-shaped tubular fluorescent lamps. A removable panel member typically comprises either a diffusion lens or a louver and is retained by the troffer housing by hinge and latch members, the panel being removable to allow replacement of the fluorescent lamps and other electrical components when needed. The panel member may have many configurations, such as flat, curved, angled, segmented, etc. In some troffers, the removable panel member further comprises a relatively rigid peripheral frame assembly with hinge members and latch members that are received by short slots or openings in the troffer housing assembly. With this structure, the troffer door assembly or louver can be unlatched and pivoted open on the hinge members, and the hinge members are often separable from the troffer housing assembly such that the entire door panel or louver may be removed. 
         [0004]    Light emitting diodes (LEDs) have been developed that are less expensive to operate and have a much greater working life than incandescent bulbs and fluorescent lamps, and when assembled into arrays of multiple LEDs have been found to be excellent replacements for the tubular fluorescent lamps in troffer assemblies. An array of LEDs mounted to a relatively rigid support structure is often referred to as an LED light bar. The LEDs are powered by a power supply commonly known as a driver. The driver and LED light bar are collectively an LED system and replace the electrical components, ballast, hardware and the like used in fluorescent fixtures. Because LED systems produce significant heat during operation, the support structure for the LED system is usually constructed to function as a heat sink and/or heat radiating member such that heat is conducted away from the LED system. 
         [0005]    The current method of retrofitting most installed troffer light fixtures to replace the fluorescent lamps and associated electrical components with one or more LED light bars involves removing the non-essential electrical components, ballast and hardware mounted within the troffer housing so that there is enough room, clearance and exposed surfaces for installation of the LED light bars, then mounting the LED light bars or panels to the interior body wall or the top/side walls of the troffer housing using mechanical fasteners. This is a time consuming and expensive process. 
         [0006]    It is an object of this invention to improve on the methodology of retrofitting troffer light fixtures by providing a novel troffer door assembly wherein one or more LED light bars are directly affixed to the peripheral frame in a manner allowing for conduction of heat from the LED light bars to the frame. The peripheral frame thereby functions as a heat sink in addition to the light bar support structure. Furthermore, the LED light bars are rigidly connected to the peripheral frame in a manner that provides increased structural integrity to the troffer door assembly. It is a further object to provide a troffer door assembly wherein the peripheral frame is formed with elongated exterior slots to receive the latch members and the hinge members in a manner that allows their positions along the frame to be adjusted as required to correspond to the variety and location of latch and hinge openings that may be encountered in the field during the retrofit process. It is a further object to provide a troffer door assembly having elongated interior slots adapted to receive therein all or some of the peripheral edges of the panel member. These objects, along with other objects not expressly set forth here, will be apparent from the detailed disclosure to follow. 
       SUMMARY 
       [0007]    One embodiment relates to a troffer door assembly configured to detachably couple to a housing of a troffer light fixture. The troffer door assembly includes a frame assembly having a plurality of interconnected frame members, a lens member retained by at least one of the plurality of interconnected frame members, a connecting member coupled to the frame assembly and configured to detachably couple the troffer door assembly to the housing of the troffer light fixture, a rigid brace member, and a plurality of LEDs attached to the rigid brace member. The rigid brace member includes a heat conductive material configured to dissipate heat produced by the plurality of LEDs. At least two of the plurality of interconnected frame members include a heat conductive material, and the rigid brace member is thermally coupled with the at least two of the plurality of interconnected frame members such that both the rigid brace member and the frame assembly dissipate heat produced by the plurality of LEDs. 
         [0008]    Another embodiment relates to a troffer door assembly configured to detachably couple to a housing of a troffer light fixture. The troffer door assembly includes a frame assembly having a plurality of interconnected frame members, a lens member retained by at least one of the plurality of interconnected frame members, a hinge member coupled to the frame assembly and configured to detachably couple the troffer door assembly to the housing of the troffer light fixture, a latch member coupled to the frame assembly and configured to detachably couple the troffer door assembly to the housing of the troffer light fixture, a plurality of LEDs, and a rigid brace member. The plurality of LEDs are attached to the rigid brace member. The rigid brace member includes a heat conductive material configured to dissipate heat produced by the plurality of LEDs. 
         [0009]    Still another embodiment relates to a method of manufacturing a troffer door assembly configured to be detachably coupled to a housing of a troffer light fixture. The method includes providing a frame assembly having a plurality of interconnected frame members, retaining a lens member with at least one of the plurality of interconnected frame members, coupling a connecting member to the frame assembly, the connecting member configured to detachably couple the troffer door assembly to the housing of the troffer light fixture, providing a rigid brace member including a heat conductive material, and attaching a plurality of LEDs to the rigid brace member such that heat produced by the plurality of LEDs is dissipated by the rigid brace member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of an embodiment of the removable troffer door assembly, showing for example a flat panel member and a single LED light bar. 
           [0011]      FIG. 2  is a partial perspective view showing an embodiment of a hinge member. 
           [0012]      FIG. 3  is a partial perspective view showing an embodiment of a latching member. 
           [0013]      FIG. 4  is a partial cross-sectional view showing an embodiment of a lens member as received by a frame member and an embodiment of the LED light bar mounted to a frame member. 
           [0014]      FIG. 5  is a partial end view of an alternative embodiment of an LED light bar. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    With reference to the drawings, the troffer door assembly with light emitting diode (LED) light bar will be described in detail with regard for the preferred or preferred embodiments. In a broad sense, the troffer door assembly is a retrofit device to replace the panel, louvers or doors of presently installed troffer light fixtures, which in certain preferred embodiments provide adjustable position latch and hinge members such that the location of the latch and hinge members can be altered to correspond to the location of the latch and hinge receiving slots of the installed troffer housing. 
         [0016]    A typical troffer light fixture comprises a shallow, rectangular or square trough or tray-like housing having a top body member and shorter depending side walls. The electrical components, ballast and hardware for retaining and operating the elongated lamp members, typically linear fluorescent tubes, are affixed to the top body member or side walls of the troffer housing. Electrical wiring is passed through the troffer housing to a power source. The troffer housing defines a rectangular or square opening and receiving frame to which a lens panel assembly, louver assembly or door assembly (referred to herein collectively as a door assembly) is connected. For the troffer door assembly, latches and hinges are mounted on a peripheral frame, and the troffer receiving frame is provided with corresponding slots to receive the latches and hinges. Typically the troffer door assembly may be removed completely from the troffer housing. 
         [0017]    As seen in  FIG. 1 , the troffer door assembly of the invention comprises a peripheral frame assembly comprising the combination of plural frame members  11  joined by connecting members  12  to form a rectangular or square configuration. The troffer door assembly further comprises a panel member or louver, to be referred to herein collectively as lens member  22 , which may be transparent, translucent or apertured such that light passes through the lens member  22  and into the room below. Lens member  22  is typically composed of acrylic or polycarbonate to minimize weight, and is usually a thin member that will flex slightly from a planar configuration when disposed horizontally in the frame assembly. Lens member  22  may be flat as shown in the drawings, or may be formed with curves, angles, edges, walls, etc., to present a more pleasing appearance when installed. 
         [0018]    The troffer door assembly further comprises at least one LED light bar assembly  24 , the LED light bar assembly  24  comprising a driver and an array of LEDs  25  positioned on an array backing member  26  in known manner to provide functionality to the LEDs  25 . The LEDs  25  may be positioned in various arrangements on the backing member  26 , as shown for example in  FIG. 5 . The LED light bar assembly  24  further comprises a rigid brace member  27 , this brace member  27  providing rigidity to the backing member  26  and covering the driver. The brace member  27  is formed of a material possessing high heat conductivity properties or characteristics (referred to as a “heat conductive material” hereafter—the term having its ordinary and plain meaning, as opposed to a heat insulating material, as the terms would be understood by one possessing ordinary skill in the art), such as, for example, aluminum metal, such that the brace member  27  functions as a heat sink and/or heat disperser (to be referred to herein collectively as a “heat sink”) to remove and dissipate heat created by the LEDs. The brace member  27  may be provided with elongated fins or ridges, as shown in  FIG. 1 , in order to radiate the heat. The ridges also serve to increase the rigidity of brace member  27  while reducing the overall weight of the LED light bar assembly  24 . Minimizing the overall weight of the troffer door assembly is important as heavier assemblies may require the use of safety chains connected to the troffer housing or other structural members in the ceiling. Electrical wiring  51  is provided for connecting the LED light bar assembly to a power source. 
         [0019]    The LED light bar assembly  24 , and more particularly the brace member  27 , is fixedly mounted to opposing frame members  11  with rigid mounting brackets  28  and mechanical fasteners  29  such that the structural rigidity of the LED light bar assembly  24  is transferred to the frame assembly, thereby increasing the overall rigidity of the frame assembly. Single or multiple LED light bar assemblies  24  may be present in a troffer door assembly, and the brace member or members  27  may extend longitudinally or transversely. In one embodiment the backing members  26  and brace members  27  of the LED light bar assemblies  24  are elongated and linear, in other embodiments the backing members  26  may be square, circular or of other configurations with linear brace members  27 , and in still other embodiments the backing members  26  and the brace members  27  may have matching configurations. 
         [0020]    The mounting brackets  28  are formed of a heat conductive material, as are the frame members  11 , such as for example aluminum metal, such that heat is transferred from the brace member  27  into the frame members  11 . In this manner the peripheral frame assembly also functions as a heat sink for the LED light bar assembly  24 . The mounting brackets  28  may be separate members connected to the ends of the brace member  27 , or the ends of the brace member  27  may be formed to extend a short distance from the main body to define a mounting flange or bracket  28 . Preferably each mounting bracket  28  is provided with a laterally extending flange member for connection to the top surface  15  of frame member  11  using a mechanical fastener  29 , such as, for example, a threaded member positioned within a threaded bore located in the top surface  15 . Alternatively, the mounting brackets  28  may be rigidly affixed to opposing frame members  11  by welding, mechanical interlock or other similar mechanisms. 
         [0021]    An elongated interior slot  19  is located in the interior surface  16  of the frame member  11 , the frame member  11  being provided with internal structural members  17  to maintain the rigidity of the frame member  11 , which is preferably manufactured as an extruded member. The interior slots  19  are adapted to receive the peripheral edges of the lens member  22 , such that the lens member  22  is supported by the frame members  11 . With all frame members  11  provided with an interior slot  19 , all four peripheral edges  23  of the lens member  22  can be received and supported by the interior slots  19  and no additional hardware is required to retain and support the lens member  22 . 
         [0022]    In the more preferred embodiment, each of the frame members  11  is also provided with an elongated exterior slot  18  disposed on the exterior surface  14 . The exposed bottom surface  13  of the frame members  11  is preferably not slotted to present a more pleasing appearance. The exterior slots  18  are utilized on one side of the frame assembly for the retention of one or more latch members  40  and on the other side of the frame assembly one or more hinge members  30  in a manner that allows the latch members  40  and the hinge members  30  to be adjusted or repositioned longitudinally along the exterior slots  18  of the frame member  11  for proper alignment with the receiving slots of the existing troffer housing. 
         [0023]    As shown in  FIG. 2 , an embodiment of the hinge members  30  comprises an extension member  32  that extends outwardly at an angle from a mounting plate  31 , the extension member  32  being configured to be received by the troffer housing slot such that the troffer door assembly may be pivoted between an open and closed position relative to the troffer housing. The mounting plate  31  is provided with a retention mechanism  33  extending into exterior slot  18  that functions to retain the mounting plate  31  on the frame member  11  while allowing the hinge member  30  to be moved in either direction along exterior slot  18 . A representative retention mechanism  33  may comprise one or more fasteners  34 , such as a rivet or threaded bolt, extending though apertures in the mounting plate  31  and connecting to one or more internal backing members  35 , such as a nut or plate, of sufficient size to prevent outward separation of the hinge member  30  from the frame member  11 . The hinge member  30  is easily assembled to the frame  11  by sliding it into the exterior slot  18  prior to assembly of the frame members  11  into the peripheral frame assembly. 
         [0024]    As shown in  FIG. 3 , an embodiment of the latch members  40  comprises a pivoting main body  42  having an upwardly extended arm or hook member  41  and an exposed actuating tab member  43 . A latch retention mechanism  44  is provided to retain the latch member  40  within exterior slot  18  of the frame member  11  such that the latch members  40  may be adjusted or repositioned along frame member  11  in order to match up with the latch receiving slots in the existing troffer housing. The latch retention mechanism  44  may comprise one or more fasteners  45  extending though apertures in the main body  42  and connecting to one or more internal backing members  46 , such as a nut or plate, of sufficient size to prevent outward separation of the latch member  40  from the frame member  11 . The latch member  40  is easily assembled to the frame  11  by sliding it into the exterior slot  18  prior to assembly of the frame members  11  into the peripheral frame assembly. Other configurations for both the latch members  40  and the hinge members  30  are possible. 
         [0025]    To retrofit an installed troffer light fixture to create an LED light fixture in place of a fluorescent lamp fixture, the installed troffer door or louver is removed from the troffer housing, the electrical components and fluorescent lamps are removed, and the incoming electrical wiring is disconnected. The hinge members  30  and latch members  40  of the troffer door assembly are then repositioned along frame members  11  to correspond to the locations of the hinge receiving slots and the latch receiving slots in the installed troffer housing. The hinge members  30  are then inserted into the installed troffer housing hinge receiving slots and the electrical wiring  51  is connected to the existing troffer housing electrical wiring. The troffer door assembly is then pivoted to the closed positioned and secured to the troffer housing by the latch members  40 . The original troffer light fixture has now been converted to an LED light fixture without the need for removal of any interior components other than the fluorescent lamps and without the need for an experienced electrician. 
         [0026]    It is contemplated that equivalents and substitutions for certain elements set forth above may be obvious to those of ordinary skill in the art, and therefore the true scope and definition of the invention is to be as set forth in the following claims.