Patent Publication Number: US-8523406-B2

Title: LED lighting assembly with detachable power module and lighting fixtures with same

Description:
TECHNICAL FIELD 
     The present invention relates to luminaries for lighting applications. More particularly, the present invention relates to lighting fixtures with LED lamp assemblies having readily replaced LED lamps and drivers. 
     BACKGROUND 
     While incandescent and fluorescent lighting provide illumination for buildings, signage, and the like, environmental and operational factors are leading to development of alternative illumination devices. A significant amount of the electrical energy necessary to operate incandescent lamps is lost as waste heat. Fluorescent lamps have operation temperatures that are cooler and thus have less heat loss arising from converting electrical energy to light. Often, however, fluorescent lighting is not as satisfactory due to the color of the light that is produced. Incandescent lamps generally have a shorter life than that of wattage-equivalent fluorescent lamps. 
     Accordingly, there is a need in the art for a readily-changed lighting assembly for lighting fixtures, which provides economical operating features. It is to such that the present invention is directed. 
     SUMMARY OF THE INVENTION 
     The present invention meets the need in the art by providing an LED light assembly for installation in a lighting fixture, comprising a heat sink defining at least one first passageway therethrough and a pair of electrical conductors each extending through the first passageway for electrical communication with a supply of electrical current. An LED chip attaches to a ceramic base and the ceramic base attaches to the heat sink. The ceramic base includes a pair of spaced-apart electricity communicating pads each operatively connected with the LED chip and with a respective one of the pair of electrical connectors. A plate defines an aperture and overlies the ceramic base for passage of light from the LED chip. 
     In another aspect, the present invention provides a lighting fixture having an LED light assembly, comprising a housing that connects to an LED assembly that comprises a heat sink defining at least one first passageway therethrough and a pair of electrical conductors each extending through the first passageway for electrical communication with a supply of electrical current. An LED chip attaches to a ceramic base and the ceramic base attaches to the heat sink. The ceramic base includes a pair of spaced-apart electricity communicating pads each operatively connected with the LED chip and with a respective one of the pair of electrical conductors. A plate defines an aperture and overlies the ceramic base for passage of light from the LED chip. A light distribution member attaches to the plate overlying the aperture and a lamp shade attaches to the housing. 
     Objects, features, and advantages of the present invention will become readily apparent upon reading of the following detailed description in conjunction with the drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exploded perspective view of an illustrative embodiment of an LED lighting assembly in accordance with the present invention. 
         FIG. 2  illustrates a cut-away side view of a lighting fixture using the LED lighting assembly illustrated in  FIG. 1 . 
         FIG. 3  illustrates a cut-away side view of an alternate embodiment of a lighting fixture using the LED lighting assembly illustrated in  FIG. 1 . 
         FIG. 4  illustrates an exploded perspective view of a second illustrative embodiment of an LED lighting assembly in accordance with the present invention. 
         FIG. 5  illustrates an exploded perspective view of an alternate embodiment of an LED lighting assembly in accordance with the present invention. 
         FIG. 6  illustrates a detailed side view of the LED lighting assembly shown in  FIG. 5  and taken along line  6 - 6 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the drawings in which like reference numerals indicate like parts,  FIG. 1  illustrates in exploded perspective view an illustrative embodiment of an LED lighting assembly  10  in accordance with the present invention for installation in a lighting fixture. The LED light assembly  10  includes a heat sink  12  having a threaded exterior  14  and a receiving side  16 . In the illustrated embodiment, the receiving side  16  is recessed and a perimeter wall  17  extends axially. A lug  19  projects from an inner surface of the wall  17 . A pair of first passageways  18  extend through the heat sink  12 . An alternate embodiment provides a single first passageway  18 . A pair of electrical conductors  22  extend through the first passageways  18  for electrical communication with a supply of electrical current (not illustrated). 
     A ceramic base  24  and an attached LED chip  26  define an LED power package  28 . The LED chip  26  includes a conventional LED device that illuminates upon supply of electrical current through a conventional LED driver  27  to the LED device. The LED driver may be situated outside of the lighting fixture for driving a plurality of connected LED devices. The LED driver receives line current (for example, in the United States, 110-240 V AC, 60 Hz) and provides power output to operate or drive the LED devices (for example but not of limitation, 4-32 V DC, at 350 mA, with a power output of 1.2 to 10.8 watts). The LED driver is conventional and selected based on the watts of the LED devices to be driven or illuminated. The LED driver discussed above is exemplary only and not a limitation on embodiments of the invention. 
     The ceramic base  24  includes a pair of electrical pads  30  that operatively connect to a supply of electrical current from the LED driver. The power package  28  attaches to the receiving side  16  of the heat sink  12 . In the illustrated embodiment, a thermally communicative epoxy  29  adheres the ceramic base  24  to the receiving side  16 . A plate  32  defining an aperture  34  attaches to the heat sink  12  on the receiving side  16  with the aperture in overlying relation to the LED chip  26  for passage of light from the LED chip. The plate  32  is received in the recess within the wall  17 . The plate  32  defines a notch or slot  31  in an edge portion. A ramp  33  extends in the plate  32  arcuately from the slot  31  to a stop member  35  extending from the plate.  FIG. 1  also shows an alternate embodiment in which a second one of the slot  31  and the ramp  33  are defined in opposing relation to the first slot  31  and ramp  33 , for assembly and use purposes, together with a second opposing lug  19  that extends from the wall  17 . Alternate embodiments use other means to detachably attach the plate  32  to the heat sink  12 , including fasteners extending through the plate into bores in the heat sink, with pivotable spring clips, with adhesive, or other holding connectors. The plate  32  further defines spaced-apart upstanding walls  37 , for a purpose discussed below. The power package  28  in the illustrative embodiment has length and width of 15 mm×12 mm and conventionally accepts a range of wattages for the LED device. 
     In the illustrated embodiment, the electrical conductors  22  comprise a pair of electrical wires  40  that extend through the first passageways  18 . Each of the wires  40  engages a respective housing  42  for electrical contact. The housing  42  is received in the passageway  18 . The housing  42  defines a channel  44 . The channel  44  receives a leg  46  of an L-shaped electrical connector  48 . A second leg  50  of the electrical connector extends laterally. The second leg  50  contacts a respective one of the pads  30  for communicating electrical current to the power package  28 . The pair of electrical connectors  48  mechanically clip the ceramic base  24  to the heat sink  12  while also providing for communication of electrical current from the supply to the power package  28  for illumination of the LED device. The L-shaped connector  48  is held firmly by the leg in contact with the channel  44 , and pressed firmly into engagement, bears forcibly through the pads  30  against the ceramic base  24  to facilitate electrical current passing through the contacting surfaces of the electrical pads  30  and the connector  48 . 
       FIG. 2  illustrates a cut-away side view of a lighting fixture  70  using the LED lighting assembly  10  illustrated in  FIG. 1 . The lighting fixture  70  includes a housing  72  configured conventionally for a lighting fixture. In the illustrated embodiment, the housing  72  defines a threaded portion  74  sized for threadably engaging the threaded heat sink  12 . The first passageway  18  in the illustrated embodiment has a first portion  76  and a second portion  78 . The first portion  78  defines a circular cross-section bore for receiving the wire  40 . The second portion  78  is rectangular in cross-section for seating the electrical connector  48  in the heat sink. As discussed above, the leg  46  of the electrical connector  48  inserts into the channel  44  of the housing  42  and contacts the wire  40  for electrical communication. The wire  40  and the leg  46  engage for electrical communication. 
     A light distributing device  84  attaches to the plate  32  with the walls  37  bearing against a base of the light distributing device  84 . The walls  37  are disposed in spaced-apart relation for defining a seat  83  that receives a base  85  of the light distributing device  84 . The light distributing device  84  is a reflector or a lens. The light distributing device  84  may also attach to the plate  32  with fasteners, adhesive, or other connector devices. 
     The heat sink  12  slidably receives a lamp shade  86  that abuts the housing  72 . In the illustrated embodiment, a ring  88  threads on the threaded exterior  14  of the heat sink  12  to secure the lamp shade  86  to the heat sink  12 . The lamp shade  86  may attach with separate fasteners such as rivets, screws, or pins; may have a pin and arcuate slot arrangement for engaging the lamp shade to the housing or to the heat sink; may use a ramp and stop structure for rotatably attaching the lamp shade to the housing or heat sink; or other conventional attaching members. The pin and slot arrangement for example uses pins projecting from the lamp shade into slots defined in the side wall of the heat sink. The lamp shade rotates as the pin is guided by the arcuate slot to seat the lamp shade relative to the housing  72 . In an alternate embodiment, the pins project from the heat sink  12  and the arcuate slots are defined in the lamp shade. The ramp and stop connector uses a structure such as that discussed above for the plate  32  detachably attached to the heat sink. 
       FIG. 3  illustrates a cut-away side view of an alternate lighting fixture  90  using the LED lighting assembly  10  illustrated in  FIG. 1 . The lighting fixture  90  includes a housing  92  configured conventionally for a lighting fixture. The housing  92  includes a pair of receiving members  94  each having a central bore (one receiving member  94  is illustrated). The wire  40   22  extends through the first portion  76  of the passageway  18  to engage the electrical connector  48  received in the housing  42  in the second portion  78 . The leg  46  of the electrical connector  48  inserts into the channel  44  of the housing  42  and contacts the wire  22  for electrical communication. 
     The heat sink  12  in the illustrated embodiment further defines a pair of second passageways  96 , as an alternate embodiment for engaging the heat sink to the light fixture. The second passageways  96  each align with a respective one of the receiving members  94  of the housing  92 . Fasteners  98  extend through the second passageways  96  and into the receiving members  94  to secure the heat sink  12  to the housing  92 . In an alternate embodiment, the plate  32  may include holes through which the fasteners  98  extend so the plate does not use the slot  31 , ramp  33 , and stop  35  with the lug  19 . It is to be appreciated that the heat sink attaches to the housing in alternative ways, including swedging the heat sink into the housing, adhesive, fasteners, or other conventional connecting mechanisms by which a heat sink attaches or connects to a housing, plate, or support. 
     The light distributing device  84  attaches to the plate  32  with the walls  37  bearing against the base  85  of the light distributing device  84 . As noted above, the light distributing device  84  is a reflector or a lens for directing or communicating light outwardly of the lamp shade  86 . The heat sink  12  slidably receives the lamp shade  86  that abuts the housing  92 . The ring  88  threads on the threaded exterior of the heat sink  12  to secure the lamp shade  86  to the heat sink  12 . 
     As discussed below, the plate  32  also presses the LED power package  28  firmly into contact with the heat sink  12  to facilitate heat transfer through the thermally communicative epoxy  29  to the heat sink. This is accomplished, as discussed below, by the plate  32  being received in the recess defined by the receiving side  16  and wall  17 . The lug  19  passes through the slot  31  of the plate  32 . Moving the plate  32 , in the illustrated embodiment by rotating through a slight angle, causes a lower surface of the lug  19  to travel on the ramp  33  until contacted by the stop  35 . This locks the plate  32  to the heat sink and provides a pressing force with the plate  32  in close contact with the heat sink  12 . 
       FIG. 4  illustrates an exploded partially cut-away perspective view of a second illustrative embodiment  100  of an LED lighting assembly in accordance with the present invention. The LED lighting assembly  100  includes an alternate heat sink  102  with the passageways  18 ,  80  and threaded exterior  103 . The heat sink  102  defines a projecting opposing side  104  that has a land  106  to which the ceramic base  24  attaches with thermally communicative epoxy  108 . A cap  110  has a plate portion  111  and a depending skirt  113 . The cap  110  defines an aperture  112  and overlies the ceramic base  24  of the power package  28 . The LED chip  26  is received within the aperture  112 . A pair of electrical connectors  114  embed in the cap  110  and have legs that engage the housing  42  that receive the wires  40  (not illustrated in  FIG. 4 ). Walls  116  extend from the cap  110  for defining a seat  118  for the base  85  of the light distributing device  84 , such as a reflector or lens. The cap  110  detachably attaches to the heat sink with mechanical locking members such as the lug  19  and ramp  33  mating members, with projecting pin and receiving slot structure, with a tapering cam that bears against a projecting pin, or other suitable mechanical engaging structure or lock device, or alternatively, with a detachable adhesive. 
       FIG. 5  illustrates in exploded perspective view an alternate embodiment of the LED assembly  130  in which a cap  132  structurally similar to the cap  110  discussed above but includes a lug  134  (shown in partial cut-away) projecting from an inner surface of a skirt  113 . The side  104  of a heat sink  136  defines a recess  138  and a perimeter extending flange  140  as best illustrated in detailed side view in  FIG. 6  taken along line  6 - 6  of  FIG. 5 . In one embodiment, the cap  130  snap-fits onto the side  104  to insert the lug  134  into the recess  138 . In the illustrated embodiment, the flange  140  defines a slot  142  for passage of the lug  134  when seating the cap  130  on the heat sink  136  with the lug  134  received in the recess  138 . The legs  46  of the electrical connectors  48  used in this embodiment insert into the housings  42  and the lateral legs  50  are disposed in contact with the underside surface of the side  104 . It is to be appreciated that in an alternate embodiment, the slot  142  and the flange  140  may be defined only in a portion of the perimeter of the side  104  of the heat sink. 
     With reference to  FIG. 1 , the LED power package  28  attaches with the epoxy  29  to the receiving side  16  of the heat sink  12 . The electrical connectors  48  engage the housings  42  by inserting the legs  46  into the channels  44 . The legs  50  contact the pads  30  for electrical communication. The plate  32  attaches by aligning the slot  31  with the lug  19 . The plate  32  seats into the recess defined by the walls  17 . The plate  32  rotates through a slight angle, with a lower surface of the lug  19  riding or traveling on the ramp  33  until contacted by the stop  35 . The plate  32  mechanically clips or locks the power package  28  to the heat sink and pushes the pad  30  and the leg  50  together for electrical communication. An alternate embodiment (not illustrated) uses a plate that slides laterally relative to the heat sink rather than rotates in order for the lug  19  to travel on a longitudinally extending ramp after sliding through a slot leading to the ramp. 
     With reference to  FIG. 2 , the LED light assembly  10  (or  100 ) attaches to the housing  72  of the light fixture  70 . This is accomplished by threading the heat sink  12  into engagement with the threads  74  of the housing  72 . With reference to  FIG. 3 , the LED light assembly  10  (or  100 ) attaches to the housing  92  with the fasteners  98  extending through the second passageways  96  and into the receiving members  94  of the housing  92 . In an alternate embodiment, the fasteners  98  pass through holes in the plate  32  to secure the plate also to the heat sink  12 . 
     With continuing reference to  FIGS. 2 and 3 , the reflector or lens for the light distribution device  84  seats against the walls  37  of the plate  32 . (With the embodiment illustrated in  FIG. 4 , the light distribution device  84  seats against the walls  116  of the cap  110 .) The heat sink  12  receives the lamp shade  86 , and the ring  88  threads on the heat sink to secure the lamp shade to the heat sink. The wires  40  connect to a supply of electrical current (not illustrated). Under selective operation with a switch, the LED light assembly  10  provides electrical current to the power package  28  for illuminating the LED device that is controlled by the LED driver on the chip. The thermally conductive epoxy facilitates transfer of heat from the LED device to the heat sink. The heat sink is an aluminum or graphite member. 
     The LED light assembly is readily assembled with a range of wattage of LED devices. The power package  28  is mechanically clipped to the heat sink so that the LED device and driver can be exchangeable among power packages of standardized sizes with different wattage of LED chip as may be required from time to time. Thus, the present invention facilitates use of LED lighting that is typically long-duration life but the LED device is readily changed if illumination requirements change or the LED device or chip fails. 
     The LED device is changed by reversing the assembly process discussed above. This is accomplished by removing the ring  88  and the lamp shade  86 . The light distributing device  84  is detached. The plate  32  is then removed to provide access to the electrical connectors  48  and the LED power package  28 . In the embodiment illustrated in  FIG. 1 , the plate  32  is rotated angularly so the lug  19  travels on the ramp  33  from the stop  35  to the slot  31 . The plate  32  is removed, providing access to the electrical connectors  48  and the LED power package  28 . The electrical connectors  48  are removed from the housings  42 . The LED power package  28  is detached from epoxy engagement with the heat sink. The epoxy  29  is cleaned from the surface of the heat sink. A new LED power package  28  is detachably engaged with fresh thermal communicative epoxy  29 . The electrical connectors  48  and the plate  32  re-installed as discussed above. The lighting distributing member  84  is attached to the plate  32  held by the walls  37 , and the lamp shade  86  attached with the ring  88 . 
     The alternate embodiments, such as the embodiment illustrated in  FIG. 4  using the cap  110 , are similarly assembled for use with a light fixture, and disassembled for replacing the detachably attached LED power package. It is believed that upon reading of the foregoing specification and discussion of the alternate embodiments, the assembly and use of such alternate embodiments will be well apparent as consistent with the present invention. 
     With reference to  FIG. 5 , the cap  132  attaches to the heat sink  136  by passing the lug  134  through the slot  142  of the flange  140 . The cap  132  then rotates through a small angle to seat the lug within the recess  138  and held by the flange  140 . In an alternate embodiment that does not include the slot  142 , the cap  132  snap-fits over the side  104  to insert the lug  134  into the recess  138 . This presses the LED power package  28  firmly into contact with the heat sink  136  to facilitate heat transfer through the thermally communicative epoxy  29  to the heat sink while the electrical connectors  48  communicate with the pads  30  for supply of electrical current to the LED power package. 
     The foregoing specification accordingly describes the present invention that provides an LED lighting assembly providing readily-replaced operationally economical illumination in lighting fixtures. It is to be understood, however, that numerous changes and variations may be made in the construction of the LED lighting assembly within the spirit and scope of the present invention and that modifications and changes may be made therein without departing from the scope thereof as set forth in the appended claims.