Patent Publication Number: US-6659627-B2

Title: Light fixture assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to junction boxes, power packs and transformers for ceiling mounted light fixtures. 
     BACKGROUND OF THE INVENTION 
     Ceiling mounted lights such as pot lights are typically constructed with the light bulb housed within a substantially cylindrical lamp housing. A transformer and an electrical junction box for connection to an electrical source are mounted on the lamp housing. Conventional ceiling mounted light fixtures are typically constructed in a linear format, such as the transformer and junction box stacked upon the lamp housing. A conventional light fixture assembly having this stacked configuration is typically greater than 6 inches in height. 
     In older buildings, 8 inch by 2-inch joists were commonly used to support floors. The use of these joists would result in a plenum of approximately 7 inches between the underside of a floor and the upper surface of the ceiling of the level below. Conventional ceiling mounted light fixtures having heights between 6 and 7 inches could be installed within the 7-inch plenum without difficulty. 
     In recent years, there has been a trend toward reducing the height of the joists between floors in order to reduce building costs. The use of joists having dimensions of approximately 6 inches by 2 inches has been introduced into residential construction projects. Correspondingly, there has been a reduction in plenum heights, and it is more common to have plenum heights of approximately 6 inches in recent commercial and residential buildings. Reduced plenum heights may also be found in the context of renovations and building re-construction projects. If there has been a redesign of the interior of a building, other service access such as air conditioning ducting may be routed through the existing plenum, reducing the height available for ceiling mounted light fixtures. Conventional light fixtures having a stacked configuration of lamp housing, junction box and transformer cannot be installed in building projects where the plenum is less than the standard 7 inches. 
     It is desirable when installing ceiling mounted light fixtures to cut a single hole in the ceiling of approximately the size of the lamp housing, and to insert the light fixture into the plenum through this opening. Installation of this type avoids the need to cut and then reseal a larger installation opening once the light fixture is installed. A flanged external frame can be mounted to the installed light fixture to provide an attractive finished appearance for the finished ceiling mounted light. 
     It is an object of the present invention to provide a light fixture for a ceiling mounted light, which can be installed within plenum spaces that are of a height, which is less than the standard 7 inch plenum. 
     It is a further object of the present invention to provide a light fixture for a ceiling mounted light which can be installed within plenum spaces though a relatively small opening in the ceiling, of a size and shape which will ultimately contain the light housing. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the present invention there is provided a light fixture assembly having a lamp housing with a top, a lamp socket within the lamp housing, a power pack operatively connected to the lamp socket, and a means for supported attachment of the power pack to the lamp housing at a position substantially lateral to the lamp housing, and not extending substantially above a plane defined by the top of the lamp housing. The power pack comprises a junction box containing a transformer operatively connected to the lamp socket, and means for operative attachment of the power pack to an electrical source. The means for supported attachment of the power pack to the lamp housing permits flexion of the junction box relative to the lamp housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and its advantages will become more apparent to those skilled in the art by reference to the following drawings, in conjunction with the accompanying specification, in which: 
     FIG. 1 is a top plan view of a light fixture according to the present invention; 
     FIG. 2 is a cross section of the light fixture taken along line A—A of FIG. 1; 
     FIG. 3 is a perspective view of the light fixture shown partially installed within a notional plenum; and, 
     FIG. 4 is a perspective view of the light fixture shown in an installed position within the notional plenum. 
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Referring to FIGS. 1 through 4, there is shown a light fixture assembly generally identified by reference numeral  10 . The light fixture assembly  10  comprises a lamp housing  12  having a top  13 . There is provided a power pack shown by general reference numeral  15 . The power pack  15 , which will be functionally discussed in greater detail below, comprises a junction box  14 . It will be understood that the functional elements of the power pack  15  are contained within the junction box  14 . For simplicity, the description of the positioning and attachment of the power pack  15  relative to the lamp housing  12  will be discussed in terms of the structural features of the junction box  14 . 
     A means  16  is provided for supported attachment of the junction box  14  to the lamp housing  12  at a position substantially lateral to the lamp housing  12 . The junction box  14 , in supported attachment to the lamp housing  12 , does not extend substantially above a plane defined by the top  13  of the lamp housing  12 . As best illustrated in FIGS. 1 and 4, the positioning of the junction box  14  substantially laterally to and not extending substantially above the lamp housing  12  permits the light fixture assembly  10  to be installed in spaces which have little vertical clearance, such as in a shallow plenum  46  between floors of a recently constructed residential building. 
     The means  16  for supported attachment of the junction box  14  to the lamp housing  12  preferably permits flexion of the junction box  14  relative to the lamp housing  12 . As best seen in FIGS. 1 and 2, the attachment means  16  preferably comprises a channel top  18  which is mounted to the lamp housing  12  by fasteners such as screws  20  and locating tabs  22 . The channel top  18  extends laterally from the top  13  of the lamp housing  12 . The flexion is provided by means of a pivotal attachment of the channel top  18  to the junction box  14 . 
     The junction box  14  comprises a first end wall  30  (shown in FIG. 1 as a dotted line) and second end wall  32 . In the conventional manner the end walls  30  and  32  are attached to first side wall  34  and second side wall  36  and to a top and a bottom, so as to form the junction box  14 . Each of the side walls  34 ,  36  extends beyond the first end wall  30 , and defines a respective opening  38  sized and positioned to receive an engagement means  40  of the channel top. Together, the side walls  34 ,  36  and their respective openings  38  comprise a first pivot portion or receptor for pivotally receiving the engagement means  40  of the channel top  18 . As best seen in FIGS. 1 and 4, the engagement means  40  of the channel top  18  provides a second pivot portion having a pair of pivot elements in the form of tabs  40  sized and positioned for pivotal retention within openings  38  of the first pivot portion or receptor. 
     In accordance with a preferred embodiment, the attachment means  16  is a channel top  18 , which itself is rigid. The flexion is provided by a pivotal attachment of the channel top  18  to the junction box  14 . It should be understood that other means of providing the desired flexion might be contemplated. For example, a pivot member may be placed within the length of the channel top, or a channel top of a flexible material could be substituted for the channel top of the present invention. Similarly, it would be understood by those skilled in the art that the use of tabs and openings is but one means of providing pivotal attachment of the junction box  14  to the lamp housing  12 , and other means could be substituted within the spirit of the present invention. 
     The power pack  15  comprises the junction box  14  which contains a transformer  42  and is operatively connected to the lamp socket  28  within the lamp housing  12 . Wiring  26  provides the operative connection to the lamp socket  28 . Conventional wiring  27 , including ground wires, is also shown within junction box  14  in FIG.  2  and provides the means for operative attachment of the power pack  15  to an electrical source. An embossment  24  is provided on the channel top  18  to permit clearance above the lamp housing  12  to facilitate the throughpassage of wires  26  for operative connection of the power pack  15  to the lamp socket  28 . The power pack  15  may also contain a thermal cut out switch  44  operatively connected to the transformer  42  and to the means for operative attachment to a power source. 
     As best seen in FIGS. 3 and 4, the light fixture assembly is installed by first inserting the power pack  15  through an opening cut in the ceiling for access to the plenum  46 . As the second end wall  32  of the junction box  14  and the thermal cut out switch  44  (if present) contact the upper limit of the plenum  46 , the means  16  for supported attachment of the junction box  14  to the lamp housing  12  permits flexion of the junction box  14  relative to the lamp housing  12 . In the preferred embodiment shown, this flexion results from the pivoting of the tabs  40  within respective openings  38  in the side walls  34 ,  36  of the junction box  14 . Once the power pack  15  is entirely within the plenum  46  it will come to rest on the upper surface  48  of the ceiling. The surface  48  forms the lower limit of the plenum  46 . The lamp housing  12  can then be inserted into the opening in the ceiling and secured in the installed position using biased locking tabs  50 , or by other securing means. As shown in FIG. 4, once installed, the power pack  15  is positioned laterally to the lamp housing  12 , and the power pack  15  does not extend substantially above the plane defined by the top  13  of the lamp housing  12 . The preferred heights of the lamp housings for use in commercial and residential lighting applications are approximately 4 inches for standard lamp housings or 3¼ inches for ultra compact lamp housings. Accordingly, the present invention results in light fixture assemblies that do not exceed the respective lamp housing heights, and which can be readily installed in very shallow plenums. 
     In the preferred embodiment of the present invention, the light fixture assembly, the power pack and junction box are designed for optimal use of plenum space. It will be obvious to those skilled in the art that the structural and functional principles of the present invention need not be limited to very compact light fixtures, but could also be utilized in other lighting applications. 
     Also, other means of achieving flexion of the power pack and junction box relative to the lamp housing could be employed by those skilled in the art without deviating from the spirit of the present invention. Thus, it will be apparent that the scope of the present invention is limited only by the claims set out hereinbelow.