Patent Publication Number: US-8109660-B2

Title: Globe deployable LED light assembly

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of provisional application Ser. No. 61/086,846 filed Aug. 7, 2008. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention relates to a light emitting assembly of the type including light emitting diodes (L.E.D.s), and more particularly, light assemblies for insertion into a globe. 
     2. Description of the Prior Art 
     For over a century, municipalities have used transparent globes, such as an “Acorn” or “Type 118” luminaire to enclose and protect street light assemblies. In addition to providing protection, transparent globes are chosen over other protective covers for their appealing ornamental design. The globe is disposed around the light assembly by inserting the light assembly through a narrow opening in the bottom of the globe. Typically, in existing globes, a high-intensity discharge (H.I.D.) light bulb or a light assembly including H.I.D. lights moves into the narrow opening of the globe as the globe is moved into position to cover the light assembly. Costly reflectors or light refracting prisms are often placed around the H.I.D. lights to increase efficiency of the light assembly and direct light in a desired direction. An example of such an assembly is disclosed in U.S. Pat. No. 4,719,548 to Orosz. 
     Recently, municipalities desire to replace H.I.D. street light assemblies including acorn-shaped globe lamps, with L.E.D, light assemblies. L.E.D.s are more efficient than H.I.D. lights, and at least a fifty percent (50%) energy savings is possible when H.I.D. lamps are replaced with properly designed L.E.D. light assemblies. An example of such an assembly is disclosed in a PCT Application No. PCT/US2008/65874 to the inventor of the present invention, Peter Hochstein. In this Hoehstein patent application, the L.E.D.s are disposed on heat sinks including fins, and the heat sinks are appropriately spaced to effectively transfer heat away from the L.E.D.s. The expected life of such L.E.D. light assemblies can exceed 10-12 years, compared to a nominal 2-3 year life of H.I.D. lamps. An L.E.D. retrofit of standard H.I.D. street lights benefits the environment, and the L.E.D. light assemblies pay for themselves in approximately five years through the energy related cost savings. 
     However, existing properly designed L.E.D. light assemblies, such as the light assembly disclosed in the Hochstein patent application, do not fit through the narrow opening of the globe. L.E.D. light assemblies currently used in globes do not provide effective thermal management. Many of the prior art L.E.D. light assemblies used in globes operate at junction temperatures approaching 100 degrees Celsius, which virtually assures early degradation of the L.E.D.s. In addition to inefficient heat transfer, prior art assemblies designed to fit through the narrow opening of the globe are often inadequate because they are very small and fill only a portion of the globe, and because light from the L.E.D.s cannot be directed in a desired direction. 
     There remains a great need for an L.E.D. light assembly that can be inserted through the narrow opening of a globe, and also provides efficient heat transfer and directs light in a desired direction. 
     SUMMARY OF THE INVENTION 
     The invention provides a globe deployable L.E.D. light assembly which can be inserted through a narrow opening in the globe. The assembly includes a base for engaging the opening of the globe. The assembly also comprises a heat sink defined by a plurality of elongated sections independent of one another and extending upwardly from the base. A plurality of L.E.D.s are disposed on the elongated sections. The assembly also includes a deployment mechanism for inserting the elongated sections into the globe in generally parallel relationship to one another and moving the elongated sections to a non-parallel open position to fill the globe. 
     The subject invention also provides a method of fabricating a globe deployable L.E.D. light assembly and inserting the assembly into the globe. The method includes forming a heat sink defined by a plurality of elongated sections independent of one another, and disposing a plurality of L.E.D.s on the elongated sections. The method also includes extending the elongated sections upwardly from a base, and pivotally connecting the elongated sections and the base for allowing the elongated sections to pivot relative to the base between a generally parallel relationship to one another and a non-parallel open position. 
     Advantages of the Invention 
     The subject invention provides an L.E.D. light assembly properly designed for effective thermal management, capable of being inserted through the narrow opening of a globe, and capable of being canted at range of desired angles toward the ground. The elongated sections of the heat sink are spaced from one another to effectively transfer heat transfer away from the L.E.D.s., which prevents early degradation of the L.E.D.s. The deployment mechanism provides a simple and cost effective way for the elongated sections to be inserted into and fill the globe. The deployable mechanism of the subject invention allows the elongated sections to be canted at a range of desired angles toward the ground, so there is no need for an expensive reflector or prism. Municipalities and other entities using globe lamps can achieve the energy related cost savings provided by L.E.D.s by installing the subject invention into new globe lamps, or by replacing existing H.I.D. street light assemblies with the subject invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a preferred embodiment of the subject invention wherein a hinge includes a leaf spring. 
         FIG. 2  is a perspective view of a preferred embodiment of the subject invention wherein the elongated sections are in generally parallel relationship to one another, the hinge includes a spiral spring, and a band encompasses the elongated sections. 
         FIG. 3  is a perspective view of a second embodiment of the subject invention including a spreader; 
         FIG. 4  is a fragmentary side view of a preferred embodiment of the subject invention showing a fin including a slot and wherein the spreader comprises a screw and spider; and 
         FIG. 5  is an fragmentary exploded view of an L.E.D. of the subject invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the Figures, a light emitting assembly  20  for insertion through a narrow opening  22  in a globe  24  is generally shown. The light assembly  20  comprises a base  26 , generally indicated, which typically includes a bottom flange  28  for engaging the narrow opening  22  of the globe  24 . The base  26  preferably includes a plurality of base sides  30  extending into the globe  24  to an upper periphery  32  of a polygonal cross-section. The bottom flange  28  connects the base  26  to the globe  24  and secures the base  26  in a stable positive within the globe  24 . 
     In one embodiment, the base  26  comprises a plate  34  and a plurality of legs  36  extending transversely from the bottom surface  38  of the plate  34 , as shown in  FIG. 1 . The plate  34  has a top surface  40  extending continuously within the upper periphery  32 , a bottom surface  38 , and the base sides  30  defining the polygonal cross section. The legs  36  are preferably spaced around the plate  34  adjacent the base sides  30 . In the embodiment shown in  FIG. 1 , the bottom flange  28  of the base  26  comprises a plurality of hooks  42  each extending from and homogeneous with one of the legs  36 . The hooks  42  engage the narrow opening  22  of the globe  24  to secure the base  26  in a stable position within the globe  24 . 
     In another embodiment, the base  26  can comprise a mounting block  44  and the base sides  30  can be further defined as a plurality of walls  46  adjoining one another and extending from the mounting block  44 , as shown in  FIG. 3 . The walls  46  define the upper periphery  32  of a polygonal cross-section. The bottom flange  28  of the base  26  can be farther defined as a collar  48  extending radially outwardly from the mounting block  44  to the opening of the globe  24 . The collar  48  extends continuously from the mounting block  44  to the opening of the globe  24  to seal the opening of the globe  24  and secure the base  26  in a stable position within the globe  24 . The collar  48  can be homogeneous with the mounting block  44 , as shown in  FIG. 3 . 
     The assembly  20  further comprises a heat sink  50  defined by a plurality of elongated sections  52 . The elongated sections  52  are independent of one another and extend upwardly from the base  26 . The elongated sections  52  are typically identical to one another and comprise side edges  54  extending continuously from a bottom end  56  to a top end  58 . The bottom ends  56  of each of the elongated sections  52  are preferably disposed at one of the base sides  30  along the upper periphery  32  of the base  26 , as shown in  FIGS. 1-3 . The elongated sections  52  can be supported by the top surface  40  of the base  26 , as shown in  FIG. 1 . Alternatively, the elongated sections  52  can extend upwardly from the walls  46  of the base  26  along the upper periphery  32 , as shown in  FIG. 3 . Each of the elongated sections  52  are typically disposed diametrically opposite another one of the elongated sections  52 , as shown in  FIGS. 1-3 . 
     The elongated sections  52  of the heat sink  50  present a mounting surface  60  and a heat transfer surface  62  facing in the opposite direction from the mounting surface  60 , as shown in  FIG. 4 . The heat transfer surfaces  62  preferably face inwardly of the upper periphery  32  and generally toward one another, while the mounting surfaces  60  face outwardly of the upper periphery  32  and generally away from one another. 
     Each of the elongated sections  52  includes a plurality of fins  64  extending transversely from the heat transfer surfaces  62  of the elongated sections  52 , so that the fins  64  face inwardly of the upper periphery  32  and generally toward one another. The fins  64  are disposed in spaced and parallel relationship to one another for transferring heat away from the heat sink  50  to surrounding air. The fins  64  typically extend continuously between the ends  56 ,  58  of each of the elongated sections  52  to present void spaces  66  between adjacent fins  64  and open at the ends  56 ,  58  for exposing the void spaces  66  between the adjacent fins  64  to air. The fins  64  can be parallel to one another or extend at angles relative to one another, as shown in  FIGS. 1-3 . The heat sink  50  and fins  64  are typically made of a thermally conductive aluminum material, such as a homogeneous aluminum or an aluminum alloy. 
     The assembly  20  can include an electrically insulating coating  68  disposed over the mounting surface  60  of the heat sink  50 . The coating  68  is less than one thousand (1000) microns thick, but preferably less than three hundred (300) microns thick. The coating  68  may be continuous and cover the entire mounting surface  60  of the heat sink  50 , or it may be disposed in circuitous tracks separated from one another by the bare metal of the heat sink  50 . 
     Circuit traces  70  are disposed in spaced lengths from one another on the mounting surface  60  of the heat sink  50  to prevent electrical conduction between the circuit traces  70 . The circuit traces  70  extend in end to end relationship along the elongated sections  52 . The coating  68  prevents electrical conduction from each of the circuit traces  70  to the heat sink  50 . The circuit traces  70  may consist of a polymetric material having metal particles dispersed therein, such as an epoxy compound with a noble metal, or a phenolic resin compounded with either copper, silver, or nickel. 
     A plurality of light emitting diodes (L.E.D.s)  72  are disposed on each of the elongated sections  52 , as shown in  FIG. 2 . The L.E.D.s  72  are typically disposed on the mounting surfaces  60  of each of the elongated sections  52  so that they can direct light away from the light assembly  20 . Typically, the L.E.D.s  72  are disposed on the mounting surface  60  to span the spaces between the ends of adjacent circuit traces  70 . Each one can have a positive lead  74  and a negative lead  76  being in electrical engagement with the adjacent ones of the circuit traces  70  to electrically interconnect the circuit traces  70  and the L.E.D.s  72 . An electrically conductive adhesive  78  secures the leads  74 ,  76  of the L.E.D.s  72  to adjacent ones of the circuit traces  70 . The L.E.D.s  72  on each of the elongated sections  52  may be electrically interconnected in series with one another and electrically interconnected in parallel with the ones on other elongated sections  52 . The L.E.D.s  72  on each of the elongated sections  52  are shown as having a uniform space between each adjacent L.E.D  72 . However, the plurality of L.E.D.s  72  on each elongated section  52  may have non-uniform spaces between one another. The electrical components of the assembly  20  are connected with printed, foil or wire conductors. 
     The light assembly  20  can include a protective and conformal coating  80  of electrically insulating material disposed over the mounting surface  60 , as shown in  FIG. 1 , to protect the L.E.D.s  72  from physical damage and moisture. The conformal coating  80  may be disposed over the L.E.D.s  72  and corresponding electrical components, including the circuit traces  70 , L.E.D.s  72  and leads  74 ,  76 , or any number of these components. The conformal coating  80  is typically a translucent and durable material, such as a two component chemically catalyzed urethane. A light shield  82  supported by the mounting surface  60  can be disposed over each of the L.E.D.s  72 , as shown in  FIGS. 1 and 3 . 
     The light emitting assembly  20  includes a deployment mechanism  84 , generally indicated, for inserting the elongated sections  52  into the globe  24  in generally parallel relationship to one another and moving the elongated sections  52  to a non-parallel open position to fill the globe  24 . The deployment mechanism  84  preferably includes a hinge  86 , generally indicated, interconnecting the base  26  and the elongated sections  52  for allowing the elongated sections  52  to pivot relative to the base  26 . The elongated sections  52  are disposed in a generally parallel relationship to one another so that they can fit through the narrow opening  22  of the globe  24 . Once the elongated sections  52  are disposed in the globe  24 , the hinge  86  allows the elongated sections  52  to pivot relative to the base  26  and move to a non-parallel open position to fill the globe  24 . The deployment mechanism  84  also includes and a retainer  88 , generally indicated, for holding the elongated sections  52  in the generally parallel relationship to one another for insertion through the narrow opening  22  in the globe  24 . 
     The deployment mechanism  84  can include a spreader  90 , generally indicated, engaging the elongated sections  52  for pivoting the elongated sections  52  about the hinge  86  from the parallel relationship to the non-parallel open position. In the embodiment shown in  FIG. 3 , wherein the base  26  comprises a mounting block  44  and walls  46  extend upwardly from the mounting block  44 , the spreader  90  can be further defined as a screw  92  extending upwardly through the base  26 , and a spider  94  having a plurality of arms  96  threadedly engaging the screw  92  and extending radially from the screw  92  to engage the fins  64 . The base  26  can define an aperture  98  disposed centrally of the elongated sections  52  so that the screw  92  can be inserted upwardly therethrough. 
     One of the fins  64  of each of the elongated section  52  can include a slot  100  extending longitudinally along at least a portion the fin  64 , as shown in  FIG. 4 , so that the arms  96  of the spider  94  can engage each of the slots  100 . A portion of the screw  92  can extend past the aperture  98  at the bottom of the base  26  and remain outside of the globe  24 , so that the screw  92  can be rotated to move the spider  94  along the slots  100  to pivot the elongated sections  52  relative to the base  26  about the hinge  86 . Alternatively, the spreader  90  can include a wedge wheel, captive nut, or other structure for engaging the fins  64  and pivoting the elongated sections  52 . A spreader  90  is not necessary if the elongated sections  52  inherently pivot about the hinge  86  relative to the base  26  upon removal of the retainer  88 , such as when the hinge  86  includes a spring  102 , as shown in  FIGS. 1 and 2 . 
     As alluded to above, the hinge  86 , which can include the spring  102 , interconnects the base  26  and each of the bottom ends  56  of the elongated sections  52 . The spring  102  can comprise a leaf spring, as shown in  FIG. 1 , being spring loaded for moving the elongated sections  52  to the non-parallel open position. The leaf spring  102  preferably comprises a compliant metallic material. Alternatively, the spring  102  can comprise a spiral spring, as shown in  FIG. 2 . 
     The retainer  88  can comprise a band  104  encompassing the elongated sections  52  for holding the elongated sections  52  in generally parallel relationship to one another for insertion through the narrow opening  22  of the globe  24 , as shown in  FIG. 5 . In the embodiment including the leafs springs  102 , the band  104  is strong enough prevent the leaf spring  102  from forcing the elongated sections  52  to the non-parallel open position. The band  104  can be cut or easily removed upon inserting the elongated sections  52  into the globe  24 . In the embodiment shown in  FIG. 3  including the screw  92  and spider  94 , the retainer  88  is defined as the slot  100  extending longitudinally along one of the fins  64  of each of the elongated sections  52 . The frictional engagement between the spider  94  and the slot  100  retains the elongated sections  52  in the parallel relationship so that the assembly  20  can be inserted into the narrow opening  22  in the globe  24 . In the embodiment shown in  FIG. 3 , a band  104  is not required, but may be used to assist in holding the elongated sections  52  in the generally parallel relationship to one another. 
     The light assembly  20  preferably comprises a flexible stop  106  attached to the top ends  58  of each of the elongated sections  52 , as shown in  FIGS. 1-5 . The flexible stops  106  arrest and position the top ends  58  of the elongated sections  52  against the globe  24  upon moving the top ends  58  of the elongated sections  52  radially outwardly to the non-parallel open position. The flexible stops  106  are spring biased so that they can be spring loaded against the globe  24 . They are approximately 0.005 inches in thickness and preferably comprise a complaint material, such as a spring temper stainless steel, so that they can conform to the globe  24 . In the embodiment shown in  FIG. 1 , including the leaf springs  102 , the flexible stops  106  comprise a material being more compliant than the material of the leaf springs  102  so that the top ends  58  of each of the elongated sections  52  can be disposed adjacent the interior surface  108  of the globe  24 . In other words, if the elongated sections  52  are not ideally centered in the globe  24 , the top ends  58  of the elongated sections  52  may not engage the interior surface  108  of the globe  24  without the flexible stops  106 . However, if included, the flexible stops  106  engage the interior surface  108  of the globe  24  and automatically adjust for centering issues. 
     A resilient tip  110  of a rubber material preferably covers and cushions at least a portion of each of the flexible stops  106  for preventing noise between the flexible stops  106  of the elongated sections  52  and the globe  24 . The resilient tips  110  also prevent top edges of the flexible stops  106  from scratching the interior surface  108  of the globe  24  when the elongated sections  52  are pivoted about the hinge  86  to the non-parallel open position. 
     The subject invention also comprises a method of fabricating a light emitting assembly  20  including a base  26 , a plurality of elongated sections  52  independent of one another and extending upwardly from the base  26 , a plurality of L.E.D.s  72  disposed on the elongated sections  52 , and a deployment mechanism  84 . The subject invention also comprises a method for inserting such a light emitting assembly  20  into the globe  24 . 
     The method of fabricating the light emitting assembly  20  comprises forming a heat sink  50  defined by a plurality of elongated sections  52  independent of one another. The elongated sections  52  can be formed by extruding a continuous strip of the heat sink  50 . The strip is formed to present a mounting surface  60  and a heat transfer surface  62  facing in the opposite direction from the mounting surface  60  and includes a plurality of fins  64  extending transversely from the heat transfer surface  62 . The continuous strip can then be cut into the plurality of elongated sections  52  each being identical to one another and presenting side edges  54  extending continuously between a bottom end  56  and a top end  58  to separate and render the elongated sections  52  independent of one another. Alternatively, the elongated sections  52  can be formed by casting, forging, or another fabrication method. 
     The method preferably includes applying a coating  68  of electrically insulating material over the mounting surface  60  of each of the elongated sections  52 , and then disposing circuit traces  70  spaced from one another on the coating  68 . 
     The method comprises disposing a plurality of L.E.D.s  72  on the elongated sections  52 . Preferably, one L.E.D.  72  is disposed in each of the spaces between the circuit traces  70 . The L.E.D.s  72  on each of the elongated sections  52  can be electrically interconnected in series with one another, and electrically interconnected in parallel with the L.E.D.s  72  on other elongated sections  52 . The method can include disposing a conformal coating  80  over the L.E.D.s  72  and corresponding electrical components. The method can also include disposing a light shield  82  supported by the mounting surface  60  over each of the L.E.D.s  72 . 
     Next the method includes extending the elongated sections  52  upwardly from a base  26 . Preferably, the method comprises disposing a bottom end  56  of each of the elongated sections  52  along an upper periphery  32  adjacent one of the base sides  30  and extending the elongated sections  52  upwardly in generally parallel relationship to one another. The method typically includes facing the heat transfer surface  62  of each of the elongated sections  52  inwardly of the upper periphery  32  and generally toward one another, and facing the mounting surface  60  of each of the elongated sections  52  outwardly of the upper periphery  32  and generally away from one another. The method can comprise disposing each of the elongated sections  52  diametrically opposite another one of the elongated sections  52 . 
     The method includes pivotably connecting the base  26  and each of the elongated sections  52  for allowing the elongated sections  52  to pivot relative to the base  26  between the generally parallel relationship and a non-parallel open position. The elongated sections  52  and base  26  can be pivotably connected at a hinge  86 , which may include a spring  102 . Preferably, the method also includes spring biasing the top ends  58  of each of the elongated sections  52 , and covering and cushioning the top ends  58  of each of the elongated sections  52  with a resilient tip  110 . 
     The method of fabricating the light assembly  20  includes disposing the light assembly  20  in a globe  24 . First, the elongated sections  52  are held in a generally parallel relationship to one another by a retainer  88  so that the group of elongated sections  52  can fit through the narrow opening  22  of the globe  24 . The holding of the elongated sections  52  can be further defined as encompassing a band  104  around the elongated sections  52 , or by engaging a spreader  90  with a slot  100  in each of the fins  64  of the elongated sections  52 . 
     The method next comprises inserting the elongated sections  52  upwardly into the narrow opening  22  of the globe  24  in the generally parallel relationship. The light assembly  20  can be mounted on a light pole, and the globe  24  can be placed over the light assembly  20 , or the light assembly  20  can be inserted into the globe  24  independent of the light pole. Once the elongated sections  52  are inside the globe  24  so that the base  26  is disposed in a desired position relative to the narrow opening  22 , the method includes moving the elongated sections  52  to the non-parallel open position to fill the globe  24 . In the embodiment shown in  FIG. 5 , the elongated sections  52  can be moved to the non-parallel open position by sliding the band  104  toward base  26  and allowing the springs  102  to force the elongated sections  52  to the non-parallel open position, or the band  104  can be cut from around the elongated sections  52 . In the embodiment shown in  FIG. 3 , the elongated sections  52  move to the open position by rotating a screw  92  to move a spider  94  along the slots  100  of the fins  64 . The screw  92  can be rotated manually, or by a power tool or screw driver. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims. In addition, the reference numerals in the claims are merely for convenience and are not to be read in any way as limiting.