Abstract:
A housing for a recessed light fixture for installation into a passenger compartment of a vehicle includes a composite trim assembly. The composite trim assembly includes a spacer and a trim member. The spacer operably engages the housing of the light fixture and the trim member is connected to the spacer. The spacer aligns the trim member with the housing such that the trim member does not contact the housing. Consequently, the trim member, which is exposed to the passenger compartment upon installation, maintains a lower temperature than the housing to which it is connected.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The subject matter disclosed herein relates to a housing assembly for a recessed light. More specifically, a recessed housing for a light emitting diode (LED) light source used in a passenger cabin of a vehicle is disclosed. 
         [0003]    2. Discussion of the Related Art 
         [0004]    Conventional lighting systems for the passenger cabin of a vehicle, for example an airplane, are well known. Historically, these lighting systems have utilized fluorescent light to illuminate the cabin. However, fluorescent light fixtures require sufficient space to house the bulbs and the ballast required to regulate current through the bulbs. Further, the light fixture requires a certain amount of power to illuminate the bulb. Because vehicles, such as airplanes, have limited cabin space and a finite amount of power supplied by the on-board electrical system, it is desirable to provide lighting fixtures of smaller size with improved energy efficiency. 
         [0005]    Advances in LEDs have resulted in light fixtures that utilize LEDs as the light source. LEDs utilize less energy to generate light intensity comparable to that of a fluorescent bulb. Further, LEDs require less space than fluorescent bulbs, resulting in light fixtures having a smaller size with improved energy efficiency that are capable of producing similar quantities of light. 
         [0006]    However, LEDs and the electronic circuits used to control them generate significant heat. The housing of such a light fixture, therefore, is typically designed to transfer the heat away from the housing. Consequently, the housing, including portions extending into the passenger cabin, can become warm or even hot to the touch. Because the height of a ceiling in a passenger cabin, for example on an aircraft, is typically not much greater than the average height of a passenger, and areas of the cabin, for example, with storage compartments over seats may further reduce the height of the ceiling, the potential exists for a passenger to contact the housing of the light fixture. Thus, it would be desirable to provide a housing for a recessed light source for use in a passenger cabin that dissipates heat generated by the light source without increasing the temperature on the cover of the housing within the passenger cabin. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0007]    The subject matter disclosed herein describes a housing for a recessed light fixture installed into a passenger compartment of a vehicle having a composite trim assembly. The composite trim assembly includes a spacer and a trim member. The spacer operably engages the housing of the light fixture and the trim member is connected to the spacer. The spacer aligns the trim member with the housing such that the trim member does not contact the housing. Consequently, the trim member, which is exposed to the passenger compartment upon installation, maintains a lower temperature than the housing to which it is connected. 
         [0008]    In one embodiment of the present invention, a light fixture includes a housing configured to accept a light source. The housing has a front surface with an outer periphery and an opening extending through the front surface. The opening defines an inner periphery of the front surface, and a spacer engages the opening in the housing. A trim member is connected to the spacer and substantially covers the spacer and the front surface of the housing. The spacer retains the trim member in alignment with the housing such that a gap is maintained between the trim member and the housing. A side wall has an inner surface extending into the housing from the opening in the front surface. A portion of the inner surface proximate to the opening is threaded, and an outer surface of the spacer is complementarily threaded to engage the inner surface of the housing. Optionally, the portion of the inner surface proximate to the opening has a first member of any other suitable mechanical connector and the outer surface of the spacer has a second member of the mechanical connector. The first and second members are complementary to positively retain the spacer within the opening. 
         [0009]    According to another aspect of the invention, the spacer further includes a generally planar rear surface, a generally planar inner surface joined to the rear surface by a beveled edge, and a lip extending radially inward. The light fixture further includes a reflective member having an opening in the rear portion to receive light radiated by the light source. The front edge of the reflective member is configured to engage the lip of the spacer. 
         [0010]    As yet another aspect of the invention, the spacer is rigidly connected to the trim member. The trim member may include a front wall, an outer wall extending rearward from the front wall to substantially enclose an outer periphery of the flange, and an inner wall extending rearward from the front wall toward the opening defined in the front surface of the housing. The spacer further aligns the trim member with the housing such that a gap is maintained between the outer wall of the trim member and the outer periphery of the flange. The light fixture may further include a lens wherein the inner wall defines a seat for the lens. 
         [0011]    As a further aspect of the invention, the light fixture may also include a plurality of internally threaded fasteners mounted to a rear surface of the trim member, and a plurality of openings extending through the spacer. Each opening corresponds to one of the threaded fasteners. An externally threaded fastener extends through each of the openings to operably engage one of the internally threaded fasteners and to positively retain the spacer to the trim member. Optionally, the trim member may be secured to the spacer by a suitable adhesive such as epoxy or glue. 
         [0012]    As still another aspect of the invention, the spacer may be made of a thermally insulating material and the housing may be made of a thermally conductive material. A plurality of fins configured to conduct heat from the housing may also be included on an outer surface of the housing. 
         [0013]    According to another embodiment of the invention, a recessed light fixture includes a housing configured to accept a light source. The housing has a rear wall, at least one side wall extending from the rear wall to a front surface of the housing, and a flange. The side wall defines an opening in the front surface of the housing, and the flange extends radially outward from an outer periphery of the side wall. A rear surface of the flange is configured to engage a front side of a mounting surface, and a mounting tab is configured to engage a rear side of the mounting surface. A spacer is connected to the side wall and proximate to the opening in the front surface of the housing. A trim member is connected to the spacer and substantially covers the spacer and the flange. The spacer aligns the trim member with respect to the housing such that a space is maintained between the trim member and the housing. 
         [0014]    These and other objects, advantages, and features of the invention will become apparent to those skilled in the art from the detailed description and the accompanying drawings. It should be understood, however, that the detailed description and accompanying drawings, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING(S) 
         [0015]    Various exemplary embodiments of the subject matter disclosed herein are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which: 
           [0016]      FIG. 1  is a perspective view of a light fixture according to one embodiment of the present invention; 
           [0017]      FIG. 2  is a partial cross-sectional view of the light fixture of  FIG. 1 ; 
           [0018]      FIG. 3  is a perspective view of the housing utilized in the light fixture of  FIG. 1 ; 
           [0019]      FIG. 4  is a front plan view of the housing of  FIG. 3 ; 
           [0020]      FIG. 5  is a side elevation view of the light fixture of  FIG. 1  engaging a mounting surface; 
           [0021]      FIG. 6  is a perspective view of a spacer and a cover utilized in the light fixture of  FIG. 1 ; 
           [0022]      FIG. 7  is a side elevation of the spacer of  FIG. 3 ; 
           [0023]      FIG. 8  is a front plan view of the spacer of  FIG. 3 ; 
           [0024]      FIG. 9  is a rear plan view of the spacer of  FIG. 3 ; 
           [0025]      FIG. 10  is a side elevation of the cover of  FIG. 3 ; 
           [0026]      FIG. 11  is a front plan view of the cover of  FIG. 3 ; and 
           [0027]      FIG. 12  is a rear plan view of the cover of  FIG. 3 . 
       
    
    
       [0028]    In describing the preferred embodiments of the invention which are illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific terms so selected and it is understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word “connected,” “attached,” or terms similar thereto are often used. They are not limited to direct connection but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    The various features and advantageous details of the subject matter disclosed herein are explained more fully with reference to the non-limiting embodiments described in detail in the following description. 
         [0030]    Turning initially to  FIG. 1 , a light fixture  10  according to one embodiment of the present invention includes a cable  12  for connecting to a network. The network may be either a standard network or a dedicated network for communication between a system controller (not shown) and individual light fixtures  10 . Commands for controlling illumination of the light fixture  10 , including but not limited to, the color or the brightness of the light fixture  10  may be transmitted over the network. 
         [0031]    The light fixture  10  further includes a housing  20  having a rear wall  22  and at least one side wall  24  extending from the rear wall  22  to a front surface  26 , shown in  FIG. 2 , of the housing  20 . The side wall  24  may be a single wall forming a generally cylindrical housing or, alternately, may include multiple side walls  24  joined at corners to form any desired shape. The side wall  24  defines an opening  28  extending through the front surface  26  of the housing  20 . The housing  20  may include a first member  23  and a second member  25 . It is further contemplated that the housing  20  may be formed from a single member or from additional members without deviating from the scope of the invention. 
         [0032]    Referring also to  FIGS. 2 and 5 , the light fixture  10  is configured to be mounted in a recessed manner through an opening in a mounting surface  50 . A flange  30  extends radially from the outer periphery of the side wall  24  proximate to the front surface  26  of the housing  20 . A front surface  34  of the flange  30  is preferably coplanar with the front surface  26  of the housing  20 . Optionally, the front surface  34  of the flange  30  may be displaced along the side wall  24  from the front surface  26  of the housing  20 . A rear surface  32  of the flange  30  is generally parallel to the front surface  34  and displaced along the side wall  24  from the front surface  26  of the housing  20 . The rear surface  32  of the flange is configured to engage a front side  56  of the mounting surface  50 . 
         [0033]    The housing  20  further includes at least one mounting tab  60  positioned along the side wall  24 . In one embodiment of the invention, three mounting tabs  60  are positioned around the periphery of the housing  20 . Each mounting tab  60  includes an opening extending through the tab having a threaded interior surface. A threaded member  40 , such as a bolt, is captive within the side wall  24  of the housing  20  and extends through the opening in the mounting tab  60 . The threaded member  40  is rotatable to turn the mounting tab  60  between a retracted position, generally adjacent to the housing  20 , and an extended position, generally perpendicular to the housing. The threaded member  40  further drives the mounting tab  60  along the side wall  24  of the housing  20  between a first position toward the rear of the housing  20  and a second position, in which the mounting tab  60  is configured to engage a rear side  54  of the mounting surface  50 . 
         [0034]    The light fixture  10  further includes a second printed circuit board  15  on which light-emitting diodes (LEDs)  14  may be mounted. A first printed circuit board  13  may include electrical circuitry to control the LEDs  14 , including but not limited to a processor, memory, communication drivers, and power regulating circuits. The first and second circuit boards,  13  and  15  respectively, are electrically connected to provide one or more of the following: control signals, feedback signals, and power signals between the two circuit boards,  13  and  15 , as required by the application. It is contemplated that the electrical circuits may be distributed in varying configurations between the first and second circuit board,  13  and  15  respectively, or, optionally, a portion of the electrical circuits may be contained external from the housing  20  or in another enclosure (not shown) separate from the housing  20 . 
         [0035]    The housing  20  includes a first cavity  33  defined, at least in part, by the interior of the first member  23  and a second cavity  35  defined, at least in part, by the interior of the second member  25 . In one embodiment of the invention, the second circuit board  15  is mounted to a rear surface  42  of the second member  25  within the second cavity  35 . The LEDs  14  are generally positioned near the center of the rear surface  42  and within the second cavity  35 . An opening  44  extending through the first circuit board  13  is configured to receive a heat tube  46 . The heat tube  46  may be a hollow or solid metal member. A first end  45  of the heat tube  46  is in communication with the rear surface  42  of the second member  25  and a second end  47  of the heat tube  46  extends to the rear wall  22  of the housing. The first end  45  of the heat tube  46  is generally aligned with the LEDs  14  mounted to the second circuit board  15 . A thermal conduction path is thereby established from the LEDs  14  through the second circuit board  15 , the rear surface  42  of the second member  25 , and the heat tube  46  to the environment exterior to the housing  20 . The housing  20  may additionally include a plurality of heat fins  48  extending away from the housing  20  to further facilitate the transfer of heat generated within the housing  20  to the environment exterior to the housing  20 . 
         [0036]    A spacer  70  engages the opening  28  in the front surface  26  of the housing  20 . According to one embodiment of the invention, a portion  29  of the inner surface  31  of the side wall  24  is threaded. Referring also to  FIGS. 6-9 , at least a portion of the outer surface  72  of the spacer  70  has a complementary thread to rotatably engage the threaded portion  29  of the side wall  24 . Optionally, the spacer  70  may engage the opening  28  by any other suitable method, including but not limited to, a friction fit, a retaining clip, or tabs configured to engage corresponding apertures. A rear surface  74  of the spacer  70  is generally planar and recessed within the second cavity  35 . An inner surface  76  of the spacer  70  meets the rear surface  74  at a beveled edge  78  and extends from the beveled edge toward a lip  82  extending radially inward from the inner surface  76 . An inner periphery of the lip  82  defines an opening  71  through the spacer  70  through which the light radiates. 
         [0037]    Referring again to  FIG. 2 , the light fixture  10  may further include a reflector  65  contained within the second cavity  35 . A rim  69  of the reflector  65  is configured to engage the rear surface of the lip  82  on the spacer  70 , and an opening  67  in the reflector  65  has a diameter large enough to allow the LEDs  14  mounted on the second printed circuit board  15  to be positioned within the opening  67 . The reflector  65  may be of any suitable form, including but not limited to parabolic or elliptical, to direct light emitted from the LEDs  14  through the opening  71  in the spacer  70 . 
         [0038]    Referring also to  FIGS. 6-12 , a trim member  90  is connected to the spacer  70 . The spacer  70  includes multiple openings  84  extending through the spacer  70 . According to the illustrated embodiment, four openings  84  are equally spaced around the circumference of the spacer  70 . It is contemplated that fewer or a greater number of openings  84  may be included in the spacer  70  at varying intervals without deviating from the scope of the invention. Each opening  84  preferably has a threaded interior and is in communication with a recess  86  in the rear surface  74  of the spacer  70 . The recess  86  is preferably large enough to receive the head of an externally threaded fastener  88 , such as a bolt, engaging each opening  84 . The externally threaded fastener  88  extends through the opening  84  and engages an internally threaded fastener  91  mounted to a rear surface  92  of the trim member  90 . The internally threaded fastener  91  may be, for example, a PEM® brand nut. 
         [0039]    The trim member  90  covers the front surface  26  of the housing  20  and the spacer  70 . A front wall  94  of the trim member extends generally from an inner periphery of the lip  82  on the spacer  70  to an outer periphery of the flange  30  on the housing  20 . For a cylindrical housing  20 , the trim member  90  is preferably ring-shaped. Optionally, the trim member may be of any suitable shape according to either the shape of the housing  20  or as desired in the application. The trim member  90  may also included an inner wall  96  and an outer wall  98 . The inner wall  96  extends rearward from the front wall  94  and defines an inner periphery of the trim member  90 . A rear surface  100  of the inner wall  96  may also define a seat for a lens  110 . Preferably, the lens  110  is positively retained between the rear surface  100  of the inner wall  96  and a portion of the reflector  65 . The outer wall  98  extends rearward from the front wall  94  and defines an outer periphery of the trim member  90 . 
         [0040]    Referring again to  FIG. 2 , the rigid connection between the spacer  70  and the housing  20  and between the spacer  70  and the trim member  90  maintain a spatial alignment between the housing  20  and the trim member  90 . A first gap  104  is defined between the rear surface  92  of the trim member  90  and the front surfaces,  26  and  34 , of the housing  20  and flange  30 , respectively. A second gap  106  is defined between the inner wall  96  of the trim member  90  and the lip  82  of the spacer  70 . A third gap  108  is defined between the outer wall  98  of the trim member  90  and the outer periphery of the flange  30 . Thus, the spacer  70  retains the trim member  90  in alignment with the housing  20  such that the trim member  90  remains out of contact with the housing  20 . 
         [0041]    In operation, the light fixture  10  is inserted through an opening in a mounting surface  50 . To insert the light fixture  10  into the mounting surface  50  the spacer  70  and trim member  90  are initially removed or left off of the light fixture  10 , providing access to the threaded members  40 . As the light fixture  10  is inserted through the opening, the mounting tabs  60  are initially positioned such that they are in a first position, adjacent to the side wall  24  and proximate to the rear of the housing  20 . The light fixture  10  is inserted until the rear surface  32  of the flange  30  engages the front side  56  of the mounting surface  50 . Once the light fixture  10  engages the front side  56  of the mounting surface  50 , the threaded members  40 , used to position the mounting tabs  60 , are rotated. The rotation of the threaded member  40  causes the corresponding mounting tab  60  to rotate outward to a second position, such that it is generally perpendicular to the side wall  24  and towards the front of the housing  20 . The threaded member  40  is rotated until the mounting tab  60  engages the rear side  54  of the mounting surface  50 . The process is repeated for each threaded member  40  and mounting tab  60  such that each mounting tab  60  engages the rear side  54  of the mounting surface  50 , positively retaining the light fixture  10  within the opening in the mounting surface  50 . 
         [0042]    After the light fixture  10  has been installed in the mounting surface  50 , the spacer  70  and trim member  90  may be installed to cover the perimeter of the housing  20  and the opening in the mounting surface  50 . If included, the reflector  65  and lens  110  may be positioned on the lip  82  of the spacer and on the rear surface  100  of the inner wall  96  of the trim member, respectively. The spacer  70  and trim member  90  assembly is rotated such that the threaded portion of the outer surface  72  of the spacer  70  engages the threaded portion  29  of the housing  20 . The assembly is rotated until the spacer  70  engages an interior feature of the housing, such as the threaded member  40  which serves as a positive stop for the spacer  70 . When engaged with the housing  20 , the spacer  70  aligns the trim member  90  with respect to the housing  20  such that the trim member  90  remains out of contact with the housing  20 . 
         [0043]    The light fixture  10  receives commands via the network to control the light output from the light fixture  10 . The commands may control, but are not limited to, intensity and color of the light emitted from the fixture  10 . The commands are received by a processor mounted on the first circuit board  13  and interpreted to control other electronic devices which, for example, regulate the power flow to the LEDs  14 . Operation of the power regulation devices and LEDs  14  each generate heat. The first end  45  of the heat tube  46  is positioned near the LEDs  14  to absorb heat generated by the LEDs and conducted through the rear surface  42  of the second member  25 . The heat tube  46  conducts the heat to its second end  47  for subsequent radiation into the surrounding environment. The first and second members,  23  and  25 , of the housing  20  are made of a thermally conductive material, such as aluminum, to conduct heat generated within the housing to the exterior of the housing  20 . The spacer  70  is made of a thermally insulative material, such as nylon, and the spacer  70  and air gaps,  102 - 106 , established between the housing  20  and the trim member  90 , reduce the conduction of heat to the trim member  90 . Thus, the trim member  90  which is within the passenger compartment is maintained at a lower temperature than the portion of the housing  20  recessed beyond the mounting surface  50 . 
         [0044]    It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also being understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention