Abstract:
Described are embodiments of a light engine installation kit and methods of installation that allow a single technician to install large, heavy, or awkwardly shaped light engines into new or existing fixture housings. The installation kits include mounting brackets that install into the fixture housing. The mounting brackets can then support the light engine by a retention tab at one end, and a tether at the other. In this intermediate position, an installer can complete the wiring before raising the light engine into its final position. Also described are lenses, wireway covers, reflectors, and end caps that provide improved sealing of the lens compartment of a light engine. The fitting of the parts provides better sealing to prevent dirt, debris, or insects from migrating into the lens compartment of the light engine and causing reduced light output or unsightly dark spots in the lens.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 62/112,017 (“the &#39;017 application”), filed on Feb. 4, 2015 and entitled “LED Retrofit Kit Installation and Method for Using Same.” The &#39;017 application is hereby incorporated in its entirety by this reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the invention relate to retrofit and installation kits for light engines into new or existing fixtures. 
       BACKGROUND 
       [0003]    The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings and each claim. 
         [0004]    Installation of light engines, especially for large or heavy lighting systems, may be difficult or dangerous and require multiple installers. Often times, a light engine may need to be retrofit into an existing lighting fixture, which may be mounted to a ceiling or other high structure. A single technician often cannot install a light engine alone because it may be too large, heavy, or the fixture housing is in a position that is not easily accessible. As a result, installation of a light engine, either into a new or existing fixture housing, may require multiple installers, increasing costs of installation or replacement, or requiring more time from available labor resources. 
         [0005]    The lens compartment of many light engines may collect dust, dirt, insects, and other debris. Generally, light engines do not include barriers to the ingress of dirt, debris, and insects. Over time, these outside contaminants can collect within the lens compartment of a light engine. The light engine output is reduced, and unsightly dark spots may become visible, particularly when the light engine is in operation. 
       SUMMARY 
       [0006]    Aspects of the present disclosure relate to installation kits to install light engines into new or existing fixture housings. The installation kits include mounting brackets that install into a new or existing fixture housings. The kit also may include one or more end caps, a retainer bracket, and a tether bracket that attach to the light engine that is to be installed. The retainer bracket has a retainer tab that engages with a receiver slot on the mounting bracket. One end of the light engine can be hung and supported by the retainer tab when it is engaged with one of the mounting brackets. The other end of the light engine can then be supported by a tether attached to the tether bracket. In this position, with one end of the light engine hanging from the fixture housing by the tether, a single installer may make all the necessary electrical connections. After the electrical connections have been completed, the installer may then raise the tethered end of the light engine into the fixture housing and secure it. 
         [0007]    Aspects of the present disclosure also relate to methods and components for better sealing of the lens compartment of a light engine. The light engine may have a lens with flanges that engage with the wireway cover of the light engine to form a tighter, more complete seal. The lens may also include ridges that abut the edges of the wireway cover to give an extra sealing point. The light engine may also include end caps with recesses that are designed to fit around the ends of the lens and reflector. The recess provides a better seating point for the lens and reflector, and helps to better seal the lens compartment. The reflector may also include a special extension to provide better engagement with the end cap. These multiple seals help prevent intrusion of bugs, dust, or other debris over longer periods of time than with traditional light engines. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a perspective view of a mounting bracket in a fixture housing, according to certain embodiments of the present invention. 
           [0009]      FIG. 2  is a perspective view of an end cap with retainer tab, according to certain embodiments of the present invention. 
           [0010]      FIG. 3  is a perspective view of an end cap with retainer tab on a light engine, according to certain embodiments of the present invention. 
           [0011]      FIG. 4  is a perspective view of an end cap with tether on a light engine, according to certain embodiments of the present invention. 
           [0012]      FIG. 5  is a perspective view of an end cap with tether and cover, according to certain embodiments of the present invention. 
           [0013]      FIG. 6  is an assembly view of the end cap and cover of  FIG. 5 . 
           [0014]      FIG. 7  is a perspective view of an end cap with tether bracket, according to certain embodiments of the present invention. 
           [0015]      FIG. 8  is a plan view of a tether according to certain embodiments of the present invention. 
           [0016]      FIGS. 9A-9D  are perspective views of the installation of a light engine into a fixture housing, according to certain embodiments of the present invention. 
           [0017]      FIG. 10  is a plan view of a light engine reflector with extension, according to certain embodiments of the present invention. 
           [0018]      FIG. 11  is an end view of a light engine without an end cap, according to certain embodiments of the present invention. 
           [0019]      FIG. 12  is an end view of an end cap with recess, according to certain embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described. 
         [0021]    Embodiments of the present invention relate to installation kits for installing an LED light engine into a new or existing fixture housing and methods of installation using the kit. While the installation kit is described and illustrated for use in a suspended fixture, it can be used in other types of fixtures including, but not limited to, surface mounted and troffer type fixtures. The kit may be supplied with a light engine or it may be used with light engines not included in the kit. It should be appreciated that any combination of the following described components, including individual components, may be used to facilitate installation of a light engine. 
         [0022]    The depicted light engines may include a reflector onto which a wireway cover is mounted on the underside of the reflector base, a plurality of LEDs mounted on the wireway cover, a lens provided over the LEDs, end caps positioned at the ends of the reflector, a driver(s) for powering the LEDs and supported on the upper side of the reflector base, as well as associated light engine wiring and hardware. However, the installation kit described herein is by no means limited for use with the light engine disclosed. Rather, it may be used with any type and configuration of light engine. 
         [0023]      FIG. 1  is a perspective view of a mounting bracket  100  with a receiver slot  102  having a wide slot portion  104 , a narrow slot portion  106 , and upwardly angled tabs  108 . The mounting bracket  100  may also include one or more tether holes  110 , fastener holes  114 , and, as shown, may be installed in a fixture housing  112  intended to house a light engine. The kit may include at least one mounting bracket  100  for mounting into the fixture housing  112  of either a pre-existing or new fixture. In one embodiment, a mounting bracket  100  may be installed within the fixture housing  112  proximate each end of the fixture housing  112 . The mounting brackets  100  may be identical or not. The mounting bracket  100  may be mounted to the fixture housing  112  using tabs, slots, or fasteners, such as screws, rivets, or the like, which take advantage of the existing geometry or holes of the fixture housing  112 . The mounting bracket  100  is preferably adapted to be used with the fixture housing  112  without the requirement for modification to the fixture housing  112 . However, the fixture housing  112  may be modified to accept the mounting bracket  100 , or the mounting bracket  100  may be modified to fit a particular fixture housing  112 . For example, in certain embodiments, a blank or standardized mounting bracket  100  may be provided that is cut, drilled, or otherwise modified on-site to fit a particular fixture housing  112 . In some embodiments, the mounting bracket  100  may include markings, pilot holes, or other features to assist an installer in modifying the mounting bracket  100  for commonly used or standardized fixture housings  112 . 
         [0024]    The mounting bracket  100  may include a receiver slot  102  having a wide slot portion  104  and narrow slot portion  106 . Upwardly angled tabs  108  (angled into the page as shown in  FIG. 1 ) are provided at the intersection of the wide slot portion  104  and the narrow slot portion  106  of the receiver slot  102 . The receiver slot  102  is sized to receive a retainer tab  204 , shown in  FIGS. 2 and 3 , which may be affixed to a first end of a light engine or an end cap  200  as described below. 
         [0025]    Still referring to  FIG. 1 , the mounting bracket  100  also may include one or more tether holes  110 . The tether holes  110  are adapted to accept a tether  226  which may be affixed to the second end of the light engine  222  or another end cap  200  (see  FIGS. 4 and 5 ). The tether  226  may terminate in a tether clip  230 , which may be a snap clip or any other type of fixation device which is compatible with the tether holes  110  in the mounting bracket  100 . 
         [0026]    End caps  200  are mounted on each end of the light engine and are designed to engage the mounting brackets  100  mounted within the fixture housing  112 .  FIGS. 2-7  illustrate various embodiments of end caps  200 .  FIGS. 2 and 3  show an embodiment of an end cap  200  with optional locator pins  212 , reflector tab recesses  214 , cover tab apertures  216 , and fastener boss  218 . 
         [0027]    A retainer bracket  202  is mounted on the outer side of one of the end caps  200 . The retainer bracket  202  has a retainer tab  204  with a wide tab portion  206 , a narrow tab portion  208 , and an optional interference tab  210 . The retainer tab  204  is designed to fit within and interlock with the receiver slot  102  of the mounting bracket  100  described above. The wide tab portion  206  is slightly narrower than the wide slot portion  104  and wider than the narrow slot portion  106  of the receiver slot  102 . The narrow tab portion  208  is narrower than the narrow slot portion  106  of the mounting bracket  100 . 
         [0028]    The size and shape of the wide tab portion  206  and narrow tab portion  208  are selected such that the wide tab portion  206  may pass through the wide slot portion  104 . Once the wide tab portion  206  of the retainer tab  204  has passed through the wide slot portion  104  of the receiver slot  102 , the retainer tab  204  may move into the narrow slot portion  106 . In this position, the narrow tab portion  208  extends through the narrow slot portion  106 , and the wide tab portion  206  interferes with the narrow slot portion  106  and cannot pass back through it. The retainer tab  204 , and any load or weight supported by it, will be held by the interference of the wide tab portion  206  of the retainer tab  204  with the narrow slot portion  106  of the mounting bracket  100 . The upwardly angled tabs  108  prevent the retainer tab  204  from sliding back into the wide slot portion  104  by interfering with the wide tab portion  206  before it enters the wide slot portion  104 . 
         [0029]    As shown, the retainer tab  204  may take on a T-shape that compliments a T-shaped receiver slot  102 . Some embodiments of the retainer tab  204  and receiver slot  102  may have different shapes, features, or qualities. For example, the retainer tab  204  and/or receiver slot  102  may take on any size, shape, or geometry so long as the wide tab portion  206  may pass through the wide slot portion  104  and then interfere with the narrow slot portion  106 . Also, the narrow slot portion  106  must be slightly wider than the narrow tab portion  208  so that the narrow tab portion  208  may pass through the narrow slot portion  106  while the wide tab portion  206  interferes with the narrow slot portion  106 . In certain embodiments, alternative structures may replace the retainer tab  204 . For example, a short tether with a ball or other structure on the end may serve the same function as the retainer tab  204  and interact with the receiver slot  102 . 
         [0030]      FIGS. 4-6  show exemplary embodiments of an end cap  200  with locator pins  212 , reflector tab recesses  214 , cover tab apertures  216 , and a fastener boss  218 . A tether bracket  224  with a tether  226  may be affixed to or through the end cap  200 . The tether  226  may have a tether clip  230 , or other mechanism to engage and secure the tether  226  to the mounting bracket  100  at one of the tether holes  110 , and a fastener  228 , such as a screw, rivet, or the like, to affix the tether  226  to the tether bracket  224 . Once the tether  226  is attached via the tether clip  230  to the tether hole  110  of the mounting bracket  100 , the tether  226 , through the tether bracket  224  and/or the end cap  200 , may support the weight of a light engine  222  during installation of the light engine into a fixture housing  112 . 
         [0031]    Referring to  FIGS. 5 and 6 , a cover  232  with a fastener hole  234  and one or more cover tabs  236  may be attached to the outer face of the end cap  200  to impart a more polished appearance to the fixture and/or to create an enclosed space for electronics or other hardware. The cover tabs  236  may engage with the cover tab apertures  216  on the end cap to snap the cover  232  onto the end cap  200 . To further secure the cover  232 , a fastener may be installed through the fastener hole  234  and into the fastener boss  218  on the end cap  200 . While shown here with reference to an end cap  200  with a tether bracket  224 , the cover  232  may be used in conjunction with any end cap  200  and/or light engine  222  shown or described in reference to  FIGS. 1-12 . In certain embodiments, the cover  232  may interact with a light engine  222  that has an end cap  200  integrated into other parts of the light engine  222 , or that has no end cap whatsoever. 
         [0032]      FIGS. 7 and 8  show exemplary embodiments of an end cap  200  with an alternative embodiment of a tether bracket  224  and a tether  226  affixed to it. The end cap  200  may include locator pins  212 , reflector tab recesses  214 , cover tab apertures  216 , and a fastener boss  218 . Tether bracket  224  includes a tether bracket slot  240  having an aperture  242 , channel  244 , and tether bracket extension  246 . The tether bracket  224  with tether bracket slot  240  is designed to engage with the tether  226  of  FIG. 8  having stops  248 . Two of the stops  248  are located near one end of the tether  226  and define a grip length  249 . The tether  226  with the stops  248  and grip length  249  is designed to engage with the tether bracket slot  240  shown in  FIG. 7 . The tether  226  also includes a toggle  250  that can be used to attach the tether  226  to the tether hole  110  on the mounting bracket  100 . To install the tether  226  in the mounting bracket  100 , the toggle  250  may be aligned with the tether  226  and inserted through the tether hole  110  lengthwise, then turned perpendicular to the tether  226  and pulled against the tether hole  110 . The toggle  250  will then not be able to pass through the tether hole  110 . A stop  248  on the end of the tether  226  prevents the tether  226  from slipping through the toggle  250 , and transfers the load from the light engine  222  to the mounting bracket  100 . 
         [0033]    Still referring to  FIGS. 7 and 8 , the tether  226  may be inserted into the tether bracket  224  prior to affixing the tether bracket  224  to the light engine  222  and/or end cap  200 . The aperture  242  of the tether bracket slot  240  is sized to be larger than the stops  248  on the tether  226 . The tether  226  is inserted through the aperture  242  until the aperture  242  is between the two stops  248  that define the grip length  249 . The grip length  249  can then translate into the channel  244 , which is sized to be larger than the tether  226  but smaller than the tether stops  248 . The tether bracket  224  may then be affixed to the light engine  222  and/or end cap  200 . The engagement of the tether bracket  224  with the end cap  200  confines the tether  226  into the channel  244 . The stops  248  will then prevent the tether  226  from exiting the channel  244 , and may transfer the load of the light engine  222  from the tether bracket  224  into the tether  226  and into a mounting bracket  100 . A tether  226  with stops  248  and a grip length  249  that engages a tether bracket  224  with a tether bracket slot  240  may provide a more secure hold compared to a tether  226  with a fastener  228 , particularly when the tether  226  is used to support a heavy light engine  222  or is permanently attached to the light engine  222  when it is installed into the fixture housing  112 . 
         [0034]    The tether bracket  224  may also include a tether bracket extension  246  extending out and away from the end cap  200 . The tether bracket extension  246  may be sized and shaped so as to cover any holes, apertures, or, in the case of an installation kit with identical mounting brackets  100 , the receiver slot  102 . The tether bracket extension  246  may then, once the light engine  222  is installed within the fixture housing  112 , provide a barrier to fire and/or electrical discharges. As a result, the end cap  200  may be made from cheaper materials that are not fire rated and/or enclosure rated. Similarly, the retainer tab  204  as shown in  FIGS. 2 and 3  may serve as a barrier to fire and/or electrical discharges. In certain embodiments, the retainer tab  204  may be sized closely to the receiver slot  102  when it is engaged to prevent fire, sparks, or arcing electricity from passing through the receiver slot  102  and contacting the end cap  200 . In some embodiments, the clearance between the retainer tab  204  and the receiver slot  102  may be approximately 0.060 inches. 
         [0035]    Referring to  FIGS. 2-7 , a number of additional features or details may be included on the end caps  200 , retainer bracket  202 , and/or tether bracket  224  to provide additional function or for ease of manufacture and assembly. For example, the end cap  200  may include locator pins  212  to help align and locate the retainer bracket  202  and/or tether bracket  224  during installation, either on site or in a manufacturing facility. The use of locator pins  212  may also facilitate installation of the retainer bracket  202  and/or tether bracket  224  by preventing the rotation or misalignment of the retainer bracket  202  and/or tether bracket  224  as the first fastener, such as a screw, bolt, or rivet, is installed. Furthermore, as shown in  FIGS. 3 and 4 , the end cap  200  may include reflector tab recesses  214  that may receive a reflector tab  220  from the light engine  222 . When the end cap  200  is installed on the end of a light engine  222 , the reflector tabs  220  may be folded over to provide a clamping or seating force on the ends of the end cap  200 . During installation, the reflector tabs  220  may help prevent distortion of the end cap  200  and/or movement relative to the light engine  222  when fasteners, such as screws or rivets, are installed through the retainer bracket  202  and/or tether bracket  224 . 
         [0036]    The retainer bracket  202  and tether bracket  224  may be attached to the light engine  222  via end plates  264  provided with or integrated into the light engine  222  (visible in  FIG. 11 ). The end plates  264  may have a number of holes which may accept fasteners such as, but not limited to, screws, bolts, and/or rivets. The retainer bracket  202  and/or tether bracket  224  may be mounted to the end plate  264  by fasteners that extend through the end cap  200 . In certain embodiments, the load is borne through the end plate  264 , and the fasteners are not threaded into the end cap  200 . Here, the end cap  200  provides a sealing function and closes off the end of the light engine  222 . However, it is also possible for the retainer bracket  202  and/or tether bracket  224  to be attached to the end cap  200  or both the end cap  200  and the end plate  264  so that the load of the light engine  222  is fully or partially supported by the end cap  200 . 
         [0037]    Still referring to  FIGS. 2-7 , a number of alternative embodiments of the light engine  222 , end cap  200 , and associated parts of the installation kit are possible. For example, the end caps  200  may be included in the light engine  222 , either as separate parts or integrated with one or more other parts of the light engine  222 . In this case, the kit may only include the mounting brackets  100 , retainer bracket  202 , tether bracket  224 , and associated hardware. In other embodiments, the end caps  200  may be integral with the retainer bracket  202  and/or tether bracket  224  and be installed on the light engine  222  in a factory or on-site. So long as the mounting bracket  100 , retainer bracket  202 , tether bracket  224 , and their associated hardware and parts maintain their functions as described, they may be integral with or produced separately from any other part included in the installation kit. In certain embodiments, the light engine  222  may be produced with parts from the installation kit included or integral with light engine  222  parts and used as a complete system. 
         [0038]    The installation kit may also be adapted for use with other lighting technologies, such as new light engine technology or Indoor Positioning systems. The installation kit may then facilitate the retrofit of new lighting technologies into existing fixture housings  112 . For example, the Indoor Positioning system uses modulation of the light engine  222  to produce a pattern that is recognizable by a cellular phone or other devices. The modulation of the light engine  222  conveys the identification of the light engine which could have a known position within a retail store or other large, lighted space. Oftentimes these types of fixture housings  112  are double housings that contain two light engines  222 . In order for a cellular phone or other device to detect the particular modulation of two adjacent light engines  222 , there must be sufficient dark space between the two light engines  222 . To accommodate this, the end caps  200  may be sized such that they provide the dark space between adjacent light engines  222  to improve the function of the Indoor Positioning system. Furthermore, the cover  232  may be sized or otherwise adapted for use with electronics that may be necessary for a particular lighting technology. In certain embodiments, as shown in  FIG. 6 , the cover  232  may provide support, protection, or an enclosed space for an electronic device  238 , such as a Bluetooth radio or the like. 
         [0039]    The installation kit may also provide error-proofing functions during assembly or installation of a light engine  222  to ensure that it functions correctly with other lighting technologies. As shown in  FIGS. 2-7 , the electronic device  238  may be mounted inside the cover  232  of the end cap  200  with the tether bracket  224 . By contrast, the retainer bracket  202  may include an interference tab  210  that projects into the space enclosed by the cover  232  and prevents installation of an electronic device  238  in combination with the retainer bracket  202 . The interference tab  210  may then ensure that the electronic device  238 , such as a Bluetooth radio in the case of the Indoor Positioning system, is located correctly in reference to the light engine  222  and/or fixture housing  112 . Similarly, the tether bracket  224  may include an interference tab  210  to prevent installation of an electronic device  238 , while the retainer bracket  202  does not have an interference tab  210 . 
         [0040]      FIGS. 9A-9D  shows an exemplary installation method of a light engine  222  into a fixture housing  112 . To mount the first end of the light engine  222 , which has already been assembled with end caps  200  and their associated parts, onto the fixture housing  112 , the retainer tab  204  is inserted upwardly into the wide slot portion  104  of the receiver slot  102  on the mounting bracket  100 . The light engine  222  is then displaced laterally towards the center of the fixture housing  112 , past the angled tabs  108  and into the narrow slot portion  106  of the receiver slot  102 . The narrow slot portion  106  of the receiver slot  102  is narrower than the wide tab portion  206  of the retainer tab  204  so that the retainer tab  204  may not pass vertically through the narrow slot portion  106  of the receiver slot  102 . Furthermore, the angled tabs  108  restrict lateral movement of the retainer tab  204  back into the wide slot portion  104  of the receiver slot  102  so as to prevent the first end of the light engine  222  from disengaging from the fixture housing  112 . In this way, the light engine  222  is securely supported in the fixture housing  112  at its first end so as to afford the installer the ability to use both hands to complete installation of the light engine  222  into the fixture housing  112 . 
         [0041]    During installation, the tether clip  230 , toggle  250 , or other fixation device, may be attached to the tether hole of the mounting bracket  100 . The tether  226  may then support the second end of the light engine  222  in a lower position relative to the first end of the light engine (see  FIGS. 9A and 9B ), thereby allowing the installer access to the back side of the light engine  222  to make the necessary electrical connections (e.g., install or connect the bond wire, ground, power source, etc.). It may be desirable for the mounting brackets  100  to be identical in that they both include features for engaging the retainer tab  204  and tether  226  of the light engine  222 . This allows the installer to install the light engine  222  in either direction without concern for which side of the host fixture housing  112  any particular mounting bracket  100  is located on. However, it is contemplated that the mounting brackets may be different (e.g., one mounting bracket  100  having the receiver slot  102  and the other mounting bracket  100  having the tether holes  110 ). In certain embodiments, the installation of the light engine  222  into the fixture housing  112  may require a particular alignment or arrangement of the retainer bracket  202  and tether  226 . For example, in a long fixture housing  112 , as shown in  FIGS. 9A and 9B , power input to the light engines  222  may come from the ends of the fixture housing  112 . The light engine  222  should be installed in this fixture housing  112  with the retainer bracket  202  near the center so that the tether  226 , and improved access to the back of the light engine  222 , is located near the power input at the outside of the fixture housing  112 . Similarly, other fixture housings  112  may have a power input at the center, and require a different installation arrangement. The installation kit may therefore be provided with mounting brackets  100  or other hardware specifically suited to any particular alignment or arrangement for a particular light engine  222 , fixture housing  112 , or installation. 
         [0042]    After the installer has made the necessary electrical connections, he/she may then raise the second, end of the light engine  222  with the tether  226  to seat it on the mounting bracket  100  and/or fixture housing  112 . The installer may then use mounting screws, bolts, or other fasteners to secure the second end of the light engine  222  into the fixture housing  112 . While such screws or other fasteners could directly engage and connect the light engine  222  to the fixture housing  112 , in some embodiments the mounting screws or fasteners pass through mounting holes in the light engine  222  and into fastener holes  114  on the mounting bracket  100  (see  FIG. 1 ). In this way, the light engine  222  is retained in the fixture housing  112  via the mounting bracket  100 . Use of the mounting brackets  100  to retain the light engine  222  in the fixture housing  112  renders the installation kit universally compatible with fixture housings  112  of virtually any shape and configuration. 
         [0043]    After securing the second end of the light engine  222  in the fixture housing  112 , the installer can similarly secure the first end of the light engine  222  in the fixture housing  112 . Engagement of the retainer tab  204  in the receiver slot  102  allows some movement or play between the first end of the light engine  222  and the mounting bracket  100  so as to permit the installer to align any mounting holes in the light engine  222  with the fastener holes  114  of the mounting bracket  100 . The light engine  222  may also be supported solely by the retainer tab  204 , not requiring fasteners on the retainer tab  204  end. 
         [0044]    It should be appreciated that any number of modifications or alterations to the individual parts of the kit or steps of installation may be made and fall within the scope of the invention. For example, the tether  226  may be permanently mounted to the light engine  222  and left attached to the mounting bracket  100  after installation. The tether  226  could then facilitate servicing, maintenance, or replacement of the light engine  222  after the initial installation. The tether  226  may also be removed during installation. In yet another embodiment, the tether  226  may be provided with the kit or separately as a tool which is affixed to the light engine  222  and mounting bracket  100  during installation, then removed and used for the installation of subsequent light engines  222  using the installation kit. 
         [0045]    Another aspect of the invention, as shown in  FIGS. 10-12 , relates to structures for sealing the lens compartment  268  of the light engine  222  defined by the lens  256  to prevent the ingress of insects, dust, and other small debris into the lens compartment  268 . The side edges of the lens  256  may include one or more flanges  258  adapted to fit snugly with, and overlap, the side edges of the wireway cover  262 . Ridges  260  may be provided, extending downwardly and perpendicular to the flanges  258  of the lens  256 . These ridges  260  help locate and seat the lens  256  on the wireway cover  262  and serve as additional barriers to the intrusion of insects and other debris where they abut with the edges of the wireway cover  262 . 
         [0046]    One or more end caps  200  may be provided with recesses  266  shaped for receiving the ends of the reflector  252  as well as the ends of the lens  256 . Seating of the ends of the lens  256  and reflector  252  within the end cap  200  recesses  266  serves to further seal the light engine  222  and prevent ingress of bugs and other debris within the lens compartment  268 . In some embodiments, the ends of the light engine reflector  252  may be provided with reflector extensions  254  that seat even further within the recesses  266  on the end caps  200 . In certain embodiments, sealing elements such as rubber, gasket material, foam, or the like may be, but do not have to be, provided between the end caps  200  and reflector  252 , reflector extension  254 , and/or lens  256  ends to enhance the seal between these components. 
         [0047]    Finally, the end cap(s)  200  may be used as a mechanism to straighten or re-form a reflector  252  and/or lens  256  during installation. If the reflector  252  and/or lens  256  have been damaged or improperly formed during manufacture, forcing the ends of the reflector  252  and/or lens  256  into the recesses  266  of the end cap  200  may return it to, or close to, the intended shape. This may be advantageous to the installer for aesthetics, proper fit of the light engine  222  within the fixture housing, or to ensure proper alignment of two light engines  222  oriented end to end and accommodated in a single fixture housing. In certain embodiments, as shown in  FIG. 11 , the light engine  222  may also include an end plate  264 . The end cap  200  may be affixed to the end plate  264  with screws, rivets, or other fasteners. The end plate  264  may provide a more secure mounting for the end cap  200 , allowing the recess  266  to more firmly press onto the ends of the reflector  252 , reflector extension  254 , and/or lens  256 , which may enhance the sealing of the lens compartment  268  and provide extra pressure to re-form or straighten the reflector  252  and/or lens  256 . 
         [0048]    Any of the above described components, parts, or embodiments may take on a range of shapes, sizes, or materials as necessary for a particular application of the described invention. The components, parts, or mechanisms of the described invention may be made of any materials selected for the suitability in use, cost, or ease of manufacturing. Materials including, but not limited to aluminum, stainless steel, fiber reinforced plastics, rubber, elastomers, carbon fiber, composites, polycarbonate, polypropylene, other metallic materials, or other polymers may be used to form any of the above described components. 
         [0049]    Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and sub-combinations are useful and may be employed without reference to other features and sub-combinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications may be made without departing from the scope of the claims below.