GLOBE DEPLOYABLE LED LIGHT ASSEMBLY

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of provisional application serial number 61/086846 filed August 7, 2008.

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0002] 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

[0003] 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. LD. 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. LD. 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. Patent 4,719,548 to Orosz.

[0004] Recently, municipalities desire to replace H. LD. street light assemblies including acorn-shaped globe lamps, with L.E.D. light assemblies. L.E.D.s are more efficient than H. LD. lights, and at least a fifty percent (50%) energy savings is possible when H. LD. 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 Hochstein 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. LD. 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.

[0005] 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.

[0006] 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

[0007] 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.

[0008] 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

[0009] The subject invention provides an L E D light assembly propeily 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 towaid 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 pπsm 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

[0010] 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 m connection with the accompanying drawings wherein

[0011] Figure 1 is a perspective view of a preferred embodiment of the subject invention wherein a hmge includes a leaf spπng,

[0012] Figure 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 hmge includes a spiral spπng, and a band encompasses the elongated sections

[0013] Figure 3 is a perspective view of a second embodiment of the subject invention including a spreader,

[0014] Figure 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

[0015] Figure 5 is an fragmentary exploded view of an L. E. D. of the subject invention.

DETAILED DESCRIPTION OF THE INVENTION

[0016] 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.

[0017] 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.

[0018] 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 further 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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) micions thick The coating 68 may be continuous and cover the entire mounting surface 60 of the heat sink 50, or it may be disposed m circuitous tracks separated from one another by the bare metal

[0023] Circuit traces 70 are disposed in spaced lengths from one anothei on the mounting surface 60 of the heat sink 50 to prevent electπcal conduction between the circuit traces 70 The circuit traces 70 extend m end to end relationship along the elongated sections 52 The coating 68 prevents electπcal conduction from each of the circuit traces 70 to the heat sink 50 The circuit traces 70 may consist of a polymetπc mateπal having metal particles dispersed therein, such as an expoxy compound with a noble metal, or a phenolic resm compounded with either copper, silver, or nickel

[0024] 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 electπcal engagement with the adjacent ones of the circuit traces 70 to electπcally interconnect the circuit traces 70 and the L E D s 72 An electπcally 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 electπcally interconnected in series with one another and electπcally 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 electπcal components of the assembly 20 are connected with printed, foil or wire conductors

[0025] The light assembly 20 can include a protective and conformal coating

80 of electπcally insulating mateπal disposed over the mounting surface 60, as shown in

FIGS. 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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 .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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.