Patent Publication Number: US-7905621-B1

Title: In-grade lighting fixture

Description:
TECHNICAL FIELD 
     The present invention relates to in-grade luminaires which hydraulically isolate the separate compartments of the fixture to prevent water seepage into the optical and electrical compartments of the fixture. Water entry into an in-grade luminaire must be prevented since such seepage can prevent the optics and electronics from proper operation. Water can enter through incorrect seals, cracked or old seals, wicking through the wire, or by other means. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an in-grade light fixture embodiment in a closed configuration; 
         FIG. 2  is a sectional view of the in-grade light fixture taken along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is an enlarged perspective view of a joint connection of the lens cover of the in-grade light fixture of  FIG. 1  with the lens cover exploded away from the light fixture and the junction box cover partially broken away; 
         FIG. 4  is an enlarged sectional view of the joint connection of the lens cover in a closed configuration taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 5  is an enlarged sectional view of the joint connection of the lens cover in a partially open configuration taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 6  is an enlarged sectional view of the joint connection of the lens cover in an open configuration taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 7  is an enlarged, rear perspective view of the in-grade light fixture of  FIG. 1  with portions of the fixture partially broken away and the potting material removed; 
         FIG. 8  is a perspective view of a ballast cover of the in-grade light fixture of  FIG. 1  with the gasket, grommet, bracket, and fasteners exploded away from the ballast cover; 
         FIG. 9  enlarged sectional view of the ballast cover with the inserted grommet and bracket taken along line  9 - 9  of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     An embodiment of an in-grade light fixture  10  is shown in  FIGS. 1-7  wherein multiple compartments are hydraulically isolated from each other. A lamp compartment  20  is provided which contains a lamping module  60 . A ballast compartment  30  containing a lamp power device such as but not limited to a ballast box  31 , electronic, magnetic, step down, or LED drivers. A side car junction box or splice compartment  40  is provided for electrical connection of the power supply wires from the external source to the internal wiring for in-grade fixture  10 . Interposed between side car junction box  40  and ballast compartment  30  is a hydraulic isolation chamber  50  which extends vertically therebetween and which may be deemed a potting compartment for hydraulic isolation of the junction box, the wires contained therein, and between the internal portion of the ballast compartment. 
     As may be readily seen from the figures, and in particular referring to  FIG. 2 , side car junction box  40  has an opening  40   a  on an upper portion thereof, opening  40   a  positioned so that a cover  41  is substantially at ground level adjacent to a lens cover  21  of lamp compartment  20  of the in-grade fixture. Side car junction box  40  has cover  41  for proper sealing of the junction box from external moisture and may be sealed after the external wires  2  from the external power supply (not shown) are electrically connected with internal electrical wires  58 , shown in  FIG. 2 , for in-grade fixture  10 . Junction box cover  41  may be of a brass or stainless steel. Side car junction box  40  has conduit entries  48  allowing external wires  2  to enter into the side car junction box for joining with internal electrical wires  58 . Either one of conduit entries  48  may allow a second set of external wires (not shown) to be connected to a second in-grade light fixture in series with light fixture  10 . Side car junction box  40  has an internal splice compartment which is removed from the other compartments, such as but not limited to lamp compartment  20 , hydraulic isolation chamber  50 , ballast compartment  30 , thereby preventing water leakage between the compartments. 
     As shown in  FIGS. 1-6 , side car junction box  40 , as indicated, has cover  41  over opening  40   a  which is substantially at ground level and adjacent to lens cover  21 . External wires  2  may be fed into side car junction box  40  for direct connection to internal electrical wires  58 . A seal or gasket  42  is positioned between junction box cover  41  and junction box compartment  40  creating a sealing engagement. Gasket  42  may be of a closed cell sponge seal such as a die cut gasket and adhesively attached to junction box cover. This results in at least gasket  42  and possibly the fasteners  43  to stay with junction box cover  41  when handling by the user. Junction box compartment  40  or junction box cover  41  may also include a positive stop or bosses, about an eighth of an inch, preventing gasket  42  from being over compressed and failing to seal junction box compartment. Seal putty and thread tape may be used on external wires  2  and conduit coming into or out of junction box  40  sealing this engagement. Also, liquid tight wire nuts  2   a  may also be used to connect external wires  2  to internal electrical wires  58 . Also located within the side car junction box  40  may be encapsulant material (not shown) for sealing of the side car junction box after splicing of external wires  2  to internal wires  58 . The encapsulant may surround and seal the wire connections and conduit entry points. The encapsulant utilized may remain a viscous liquid, gelatinous consistency or cure to a rubber or solid material such as RTV silicate. Once the wires are electrically connected, the encapsulant may be poured into side car junction box  40  and junction box cover  41  may be placed thereon to assure that no water leaks from the side car junction box into the hydraulic isolation chamber  50 . 
     As shown in  FIGS. 1 ,  2 , and  7 , hydraulic isolation chamber  50  extends vertically between side car junction box  40  and extending through the wall of ballast compartment  30  providing electrical connectivity to ballast box  31  of in-grade fixture  10 . Hydraulic isolation chamber  50  is provided such that internal wires  58  extending therethrough may be surrounded by a potting compound or material  59  which cures to a hardened state. Potting material  59  may be, but is not limited to, Hysol® ES4512. By placing potting material  59  into hydraulic isolation chamber  50 , the potting material seals side car junction box  40  and ballast compartment  30  from moisture originating from other compartments and from outside of the fixture  10 . Prior to placement of potting material  59  within hydraulic isolation chamber  50 , wires  58 , as shown in  FIG. 2 , are placed so as to extend through the vertically extending hydraulic isolation chamber and are electrically connected to a pin interface of a male/female connector  37  inside of ballast compartment  30 . Thus, internal wires  58  extend from side car junction box  40  to connector  37  into the interior of ballast compartment  30 . As shown in  FIG. 7 , internal wires  58  are permitted to extend through the ballast compartment wall by an aperture interface  52  having at least one aperture or a plurality of apertures  52   a ,  52   b ,  52   c  each receiving a wire  58 . As shown in  FIG. 7 , each internal wire  58  is also stripped of its plastic jacket to expose a portion of bare wire  58   a . The stripped jacket or bare wire  58   a  is preferably about a half inch in length, but may be of any dimension. This portion of each bare wire  58   a  is positioned across a groove  54  whereby the subsequently filled-in potting material  59  into chamber  50  is able to flow into groove  54  and more specifically surround the circumference of each bare wire  58   a  to provide an anti-wicking mechanism preventing moisture from being transferred along wires  58  from one compartment to another. Internal wires  58  may be adhesively or mechanically, for example taped or vertical grooves as shown in  FIG. 7 , held to position each bare wire  58   a  across groove  54  while potting material  59  is applied. Each bare wire  58   a  is separated from each other and extends across a portion of the groove  54  to provide clearance around the circumference of each bare wire  58   a . The clearance provided by the groove  54  allows the potting material  59  to be applied and fully flow around each bare wire to completely encapsulate the bare wire to provide anti-wicking. The vertically extending hydraulic isolation chamber  50  therefore adequately isolates side car junction box  40  and internal electrical wires  58  from the internal electrical components of ballast compartment  30 . 
     As shown in  FIG. 2 , substantially the entire hydraulic isolation chamber  50  with groove  54  is filled with potting material  59  and the material surrounds wires  58  and bare wires  58   a , the aperture interface  52  between hydraulic isolation chamber  50  and ballast chamber  30 , and an aperture interface  49  between the hydraulic isolation chamber  50  and junction box  40  thereby preventing any moisture from progressing between the ballast compartment and the junction box even should water wick through the wires. With bare wires  58   a  surrounded by potting material  59 , a water tight barrier is placed between the ballast compartment and the junction box. 
     Also shown in  FIG. 2 , side car junction box  40  therefore is maintained in moisture free condition by liquid tight wire nuts  2   a , sealed cover  41  on opening  40   a  thereof, the seal putty and thread tape of the line voltage inlet  48  and possibly line voltage outlet to a second fixture, and potting material  59  set within hydraulic isolation chamber  50 . Any moisture therefore is prevented by entry into lamp compartment  20  or ballast compartment  30 . 
     As shown in FIGS.  2  and  7 - 9 , within ballast compartment  30  are found lamp wires  38   b  which electrically connect ballast box  31  with lamp module  60  of lamp compartment  20 , and ballast wires  38   a  which electrically connect through male/female connection  37  with internal electrical wires  58 . Ballast compartment  30  is sealed on an open upper end  30   a  by a ballast cover  33  which has an aperture  33   a  for allowing lamp wires  38   b  to connect ballast box  31  to lamp module  60  in lamp compartment  20 . Ballast cover  33  not only is in sealing engagement with ballast compartment  30 , but it also permits the user to access the ballast compartment for maintenance and installation of ballast box  31 . Lamp compartment  20  encloses and positions lamping module  60 . Lamp compartment  20  is sealed at an open upper end  20   a  by a lens cover  21 . Lens cover  21  has a lens  27  which may be in contact with a gasket  22  at its lower end and may further be substantially surrounded by a lens ring  26  at its upper end. Ballast cover  33  seals an open lower end  20   b  of lamp compartment  20  creating a sealed lamp compartment separate from the other housing compartments of fixture  10 . Open lower end  20   b  of lamp compartment  20  coincides with open upper end  30   a  of ballast compartment  30 . Lens  27  is in sealing engagement with lamp compartment  20  by means of gasket  22  thereby preventing any moisture from entering into lamp compartment  20  from the outside. Gasket  22  is positioned between lens  27  and lamp compartment  20  creating a sealing engagement. Gasket  22  may be adhered to the lens but may alternatively be positioned separately within lamp compartment  20 . The lens cover  21  and lamp compartment  20  engagement includes ledge  23  which interact with lens ring  26  to preclude over compression of gasket  22 . Ledge  23  projects from the upper end of lamp compartment as shown in  FIGS. 2 ,  3 ,  5 , and  6 . If gasket  22  is secured upon lens  27 , the gasket may be seen through the lens resulting in a “visual seal” because the gasket engagement with the lens changes appearance upon being compressed. For example but not limited to changes in the color of the seal and lens engagement may indicate a sufficient sealing engagement and an incomplete sealing engagement. It is to be understood that although gasket  22  is sealed between lens  27  and lamp compartment  20 , any number of sealing methods, constructions, quantities, and orientations known in the art may be used to seal the lens cover to the lamp compartment. 
     As shown in  FIGS. 1-6 , lens cover  21  having lens  27  and lens ring  26  are in sealing engagement with lamp compartment  20 . Lens gasket  22  may be of a silicone composition. Lens ring  26  which has an arm  72  on one side may be formed of a brass or stainless steel. Lens cover  21  may be positioned in a closed configuration ( FIGS. 1 ,  2 , and  4 ) permitting a sealing engagement with lamp compartment  20 , and in an open configuration ( FIGS. 3 ,  5 , and  6 ) whereby ballast cover  33 , ballast box  31 , and lamp module  60  may be inserted or removed from lamp compartment  20 . One embodiment of lens cover  21  has a joint connection  70  between arm  72  and lamp compartment  20 . Joint connection  70  may provide a pin-in-slot joint engagement as discussed below permitting both translational and rotational movement of lens  27 . The pin-in-slot engagement allows the joined bodies to pivot with respect to each other and to translate with respect to each other. Previously, a hinged connection would allow only rotation of a lens about a fixed axis. Lens  27  may be able to rotate upwards away from compartment  20  from about 0 to about 180 degrees, preferably past the 90 degree point to allow a “hands free” position wherein lens cover  21  remains naturally in an open configuration allowing accessibility of the interior of the light fixture. As shown in  FIG. 6 , lens  27  may be restricted from opening past about 93 degrees due to contact between arm  72  and other structures of the light fixture, such as junction box cover  41 . Joint connection  70  allow for engagement between arm  72  and a socket  76  provided in lamp compartment  20 . Lens cover  21  as shown in  FIGS. 2-6  has lens ring  26  circumscribing lens  27  and having arm  72  projecting therefrom. Arm  72  includes one or more projecting or opposing pins  73 . Socket  76  with at least one cam surface  77 , however socket  76  is shown as having two cam surfaces  77  (see  FIG. 3  showing one of such cam surfaces) spaced on opposite sides of a deeper groove  78  of the socket. A left cam cover  79   a  and a right cam cover  79   b  define the upper portion of the socket  76  and are disposed over each respective cam surfaces  77 . Left and right cam cover  79   a  and  79   b , respectively, define an aperture  79   c  ( FIG. 3 ) permitting rotational movement of arm  72  and lens  27  upwards away from compartment  20  and translational movement within socket  76  radially towards the center of open upper end  20   a  of compartment  20 . Not only does joint connection  70  allow for translational and rotational movement, joint connection  70  may be “open” such as to releasably secure or separate lens cover  21  from lamp compartment  20 . Lens cover  21  with arm  72  may be separated from socket  76 , as shown in  FIG. 3 , if desired by the user, by permitting pins  73  to travel through opposing slots  79   d  on either side of cam cover aperture  79   c . Opposing slots  79   d  permit insertion and removal of opposing pins  73  on lens cover arm  72 . Opposing pins  73  and arm  72  are inserted and retained within socket  76  as they are cammed under cam covers  79   a  and  79   b . Arm  72  with opposing pins  73  travel along each of cam surfaces  77  permitting lens cover  21  to travel between the closed configuration and the open configuration. When lens cover  21  is placed in the closed configuration as shown in  FIGS. 1 ,  2 , and  4 , arm  72  is forced upward as it rolls along the linear curvature of cam  76 , thus, compressing gasket  22  to sealingly engage lamp compartment  20  by placing a downward force on ring  26  coupled with lens fasteners  21   a . As shown in  FIG. 4 , gasket  22  in the closed configuration will typically seal against a vertical peripheral surface and a bottom horizontal surface of lamp compartment  20 . As shown in  FIGS. 4-6 , when lens cover  21  is opened, the arm  72  of lens cover  21  moves translationally and rotationally along cam surfaces  77  relative to lamp compartment  20 . The open configuration of lens cover permits access to lamp compartment  20  through open upper end  20   a . More specifically, opposing pins  73  travels along cam surfaces  77  under bracket cam covers  79   a  and  79   b  from the closed configuration to the open configuration. The middle section of groove  78  permits the distal end or portions of the arm  72  to rotate about pins  73  within socket  76  and may also advantageously retain any accumulated dirt or debris within socket  76  while still permitting joint connection  70  to function. 
     As shown in  FIG. 4 , in a closed configuration lens gasket  22  is compressed between lens  27  and lamp compartment  20  by placing a downward force on lens ring  26  coupled with joint connection  70  and opposing lens fasteners  21   a . Again the compression of gasket  22  is limited by the engagement between ledge  23  of lamp compartment  20  and ring  26 . Upon removal of lens fasteners  21   a , gasket  22  has sufficient elasticity to uncompress and raise lens cover  21  opposite joint connection  70  to enabling a user to grasp the lens ring and open the lens cover without the use of a handle. Lens cover  21  is translationally moved outwards away from junction box cover  41  and rotated upwards away from lamp compartment  20 . During the translational movement, arm  72  with opposing pins  73  translates within socket  76  along the linear curvature of cam surfaces  77  towards the center of lamp compartment open upper end  20   a  while the lens ring  26  and lens  27  rotates upwards away from lamp compartment  20 . Cam surfaces  77  are shown in  FIGS. 3-6  as concave in shape, but are not limited to such. As arm  72  of lens cover  21  translationally travels from its closed configuration position to its open configuration position within socket  76 , the opposing pins  73  traverse below the opposing aperture slots  79   d  of left and right cam covers  79   a  and  79   b . Again, the user may apply an upward force to remove lens cover  21  by passing the opposing pins  73  through the slots  79   d , thus creating an “open” joint or releasable joint connection. However, joint connection  70  may be a “closed” joint (not shown) that lens cover  21  may not be releasable. Opposing pins  73  are shown as fixed but may be rotatable relative to the remainder of the arm  72  or have rollers affixed to each pin and still function to travel along the cam surfaces  77 . Translational movement of the lens cover  21  within socket  76  when traveling to the open configuration is not limited to radially towards the center of the open upper end  20   a . For example translational travel may be in the opposite direction radially away from the center of the open upper end  20   a  when opening the lens cover. 
     As depicted in  FIGS. 3-6 , joint connection  70  of light fixture  10  permits the user to open lens cover  21  to provide access to the interior of lamp compartment  20  and ballast compartment  30 . A pivotable lens cover  21  reduces the amount of dirt and other contaminates that might otherwise be introduced to gasket  22  or lens cover  21  if it were removed from lamp compartment  20 . Because the lens cover  21  is pivotable, the user does not have to remove the lens cover and separate from fixture  10  but positions the lens cover to the open configuration. Once in the open configuration, the user has both hands available for maintenance and installation of, but not limited to, lamp module  60 , ballast box cover  33 , and ballast box  31 . However, lens cover  21  may still be removed if required by the user. Also, the sealing engagement of junction box cover  41  with junction box  40  is maintained while lens cover  21  is being opened, closed, or removed. The joint connection  70  also allows a substantially flush appearance to be maintained between junction box cover  41  and lens cover  21  when each are in the closed configuration. The pivoting construction of lens cover  21  reduces the number of fasteners required to secure the lens cover and compress gasket  22 . As shown in  FIGS. 1-3 , fasteners  21   a  need only to be positioned opposite joint connection  70  instead of around the entire periphery of lens cover  21  as required in previous designs. A reduced number of fasteners reduces the time required for engaging and disengaging lens cover  21  from lamp compartment  20  as well as eliminating the need for a “star pattern” torque sequence required in previous designs to prevent the lens cover from unevenly seating and over compressing the gasket which would adversely affect the sealing properties of the gasket. 
     Although one embodiment of joint connection  70  is shown in  FIGS. 2-6 , it is to be understood that the joint connection concept shown in the drawings may take on a variety of shapes, sizes, constructions, and orientations and still provide rotational and translation movement of lens cover  21  or any other cover or lid applied to light fixture  10 . For example, a junction box cover or a ballast cover each may have a joint connection  70  by itself or in combination with lens cover  21 . 
     As shown in  FIG. 2 , lamping module  60  is comprised of a reflector  63 , lamp  64 , and lamp socket  65 , the lamp socket being electrically connected by lamp wires  38   b  to ballast box  31 . Within lamping module  60 , lamp  64  which may be either incandescent, fluorescent, LED, or HID, emits the desired light which may be reflected by a reflector  63 , if desired. The light passes through the lamping module lens  67 , if used in the fixture, providing illumination through lens  27  of lamp compartment  20 . Lamping module  60  may be placed on a gimbal mechanism  62  to provide, for example, up to about 15 degrees of tilt and 360 degrees of rotation. By separating lamping module  60  from the remaining electronics and construction of the in-grade fixture  10 , relamping of fixture  10  becomes a relatively easy task. Positioning lens cover  21  into an open configuration as shown in  FIGS. 3 ,  5 , and  6  permits a user to remove the entire lamping module  60  and replace it without having to enter into any of the other sealed compartments provided within the in-grade fixture  10  as described herein. 
     As shown in  FIG. 2 , lamping module  60  is in electrical communication with ballast box  31  through lamp wires  38   b . A ballast box  31  is needed for HID lamps, LEDs, and fluorescents but will not be required for incandescent lamps. Ballast box  31  is electrically connected to junction box  40  by ballast wires  38   a  and internal electrical wires  58 . As depicted in FIGS.  2  and  7 - 9 , ballast box  31  may be releasably secured to a substantially vertical projection  34  depending from the bottom surface of ballast cover  33 . By doing so, ballast box  31  may be readily installed and removed by removing ballast cover  33  from its sealing engagement with ballast compartment  30 . Ballast cover  33  may be of aluminum coated with a kalium dichromate finish. Ballast cover  33  may also have a handle  35  ( FIG. 8 ) for user convenience when handling. Ballast box  31 , having a number of electronic components located therein, may be a brick ballast module in that it may be filled with potting material encasing the interior of the ballast module to assure a continued moisture-free environment for the electronics placed therein. Alternatively, a ballast may be provided in the lamping module for designs using a fluorescent lamp. 
     As shown in  FIGS. 2 and 8 , ballast box  31  may be releasably secured adjacent ballast cover  33  through a variety of attachments using, for example, mechanical or adhesive means, or it may be releasably secured (not shown) to ballast compartment  30 . As shown in  FIG. 8 , lamp wires  38   b  passes through aperture  33   a  of ballast cover  33  via a grommet  36  having at least one opening or a plurality of openings, permitting the wires  38   b  to pass through together or individually. Aperture  33   a  of ballast cover  33  may be tapered ( FIG. 9 ) for sealing engagement with a tapered grommet  36  ( FIGS. 8 and 9 ). Grommet  36  may be of a silicone composition or 100% silicone. As shown in  FIG. 9 , a bracket  36   a  pulled down by fasteners  36   b  acts to compress and seal grommet  36  within tapered aperture  33   a  of ballast cover  33 , and squeezes lamp wires  38   b  creating a secured and sealed engagement. Thus, secured, grommet  36  acts to form a seal about lamp wires  38   b  where they extend between ballast compartment  30  and lamp compartment  20  through ballast cover  33 . Ballast cover  33 , as described above and shown in  FIG. 8 , carries or rests against a gasket  32  or other sealing mechanism to form a seal with ballast compartment  30 . Gasket  32  may be a molded member, such as a silicone gasket. As shown in  FIGS. 7 and 8 , a plurality of key slots  33   b  permits the use of fasteners  34  to compress gasket  32  of the ballast cover  33  to a point against ballast compartment  30  where a series of bosses  39 , spaced apart by 120 degrees, limits over-compression. Gasket  32 , as shown in  FIG. 2 , may seal on a substantially vertical peripheral surface and bottom horizontal surface of ballast compartment  30 . 
     Upon assembly, ballast box  31  and cover  33  are inserted through open upper end  20   a  and open lower end  20   b  of lamp compartment  20 , and ballast wires  38   a  are placed appropriately in the male/female connection  37  which connects them with internal electrical wires  58  from junction box  40 . Subsequently ballast cover  33  is sealingly engaged with ballast compartment  30 . Lamp wires  38   b  projecting from ballast cover  33  through grommet  36  are subsequently connected to lamp module  60  upon the insertion of the lamp module into lamp compartment  20 . Subsequently, lens cover  21  is positioned in sealing engagement with open upper end  20   a  of lamp compartment  20 . 
     One advantage of in-grade fixture  10  is that by providing the vertically extending hydraulic isolation chamber  50  with potting material  59  that encompasses internal wires  58  and bare wires  58   a , ballast compartment  30  is protected from water seepage originating in junction box  40 . More specifically, by isolating bare wires  58   a  with potting material  59  within hydraulic isolation chamber  50 , a hydraulic barrier is presented which allows for electrical communication from the sealed junction box  40  to the sealed ballast compartment  30  and continuing to lamp module  60  of the sealed lamp compartment  20 , while preventing any disruption due to moisture entering therein. 
     By means of the structure of in-grade light fixture  10 , moisture is prevented from entering into ballast compartment  30  through wicking or other leaking mechanisms and this prevents moisture from entering into lamp compartment  20 . Water ingress is prevented through the use of potting material  59  encasing internal electrical wires  58  extending through the chamber  50  and also utilizing the potting material surrounding bare wire  58   a  within groove  54  to prevent wicking along the wires  58 . Hydraulic isolation chamber  50  may be set with the potting material  59  prior to shipment of the combined fixture so that no additional entry into the hydraulic isolation chamber is required upon installation of in-grade light fixture  10 . Upon installation, the user merely has to connect external wires  2  at side car junction box  40 , seal the line voltage entry  48  and exit points, if present, and seal cover  41  over the junction box opening  40   a.    
     It is understood that while certain embodiments of the invention have been illustrated and described, it is not limited thereto except insofar as such limitations are included in the following claims and allowable functional equivalents thereof.