Embodiments of the present invention relate to in-grade light fixtures having hermetically sealed components that enable water and air to pass through the fixture without degrading the fixture components.
In-grade light fixtures are installed in the ground such that the top of the fixture is substantially flush with the ground and light is emitted upwardly from the fixture. This installation environment exposes the fixtures to a variety of environmental elements (e.g., water, dirt, sand, mud, etc.) that over time can damage the fixture components and detrimentally impact operation of the fixture. As a result, in-grade light fixtures are typically water-tight to prevent such elements from penetrating into the fixture.
In-grade fixtures are often intended to illuminate specific targets (such as columns, flags, and other architectural structures) or large wide targets (such as facades, trees, walls, signs, etc.). High output LEDs are often used to attain the desired illumination. However, such LEDs generate a great deal of heat during operation. Given that the LEDs are sealed within the fixture, it is difficult to disseminate the heat generated by them. After time, the heat can reduce the useful life of the fixture, thus requiring component replacement or is some cases entire fixture replacement. Replacement of critical components for an in-grade light fixture can require opening critical sealed areas thus subjecting the fixture to future damage due to improper reassembly. In addition, removing and replacing an entire fixture can be both expensive and time consuming.
The terms “invention,” “the invention,” “this invention” and “the present invention” used in this patent are intended to refer broadly to all of the subject matter of this patent and the patent claims below. Statements containing these terms should not be understood to limit the subject matter described herein or to limit the meaning or scope of the patent claims below. Embodiments of the invention covered by this patent are defined by the claims below, not this summary. This summary is a high-level overview of various embodiments of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to the entire specification of this patent, all drawings and each claim.
Embodiments of the present invention are directed to in-grade light fixtures having hermetically sealed components such that water and air may flow through the fixture without degrading or detrimentally impacting operation of the light fixture and while enhancing heat dissipation from the fixture.
The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.
Turning in detail to the figures, an exploded view of one embodiment of a light fixture 10 is illustrated in
The fixture housing 12 houses and/or supports the LED module 14, finishing piece 16, and power module 70.
The fixture housing 12 may be formed of any material having suitable structural integrity to support these light fixture components. The fixture housing 12 should also be formed of materials that do not degrade, corrode, or otherwise deteriorate in the in-grade environment. In some embodiments, the fixture housing 12 may be formed of metallic or polymeric materials. For example, the fixture housing 12 can be formed from injection molded polymeric material (e.g., polysulfone, PVC, polycarbonate, or other suitable polymeric material).
As shown in
The fixture housing 12 can include a support ring 18 that is received in the fixture housing 12 and supported on at least one projection 20 extending from the interior wall 21 of the fixture housing 12. In some embodiments, the support ring 18 is formed integrally with the fixture housing 12. The support ring 18 can include openings 22 that extend from a top surface 24 of the support ring 18 to a bottom surface 26 of the support ring 18. When the support ring 18 is positioned within or formed with the fixture housing 12, the openings 22 are in fluid communication with an interior cavity 23 of the fixture housing 12 such that the openings 22 in the support ring 18 allow air and water to pass through the support ring 18 and enter the interior cavity 23 of the fixture housing 12. The support ring 18 can also include an inner flange 28 for supporting the LED module 14, as described in more detail below.
As been seen in
An embodiment of the LED module 14 is shown in
In some embodiments, the can 30 is a metallic can onto which the heat sink 50 is die cast or fused such that the heat sink 50 forms the base of the LED module housing 53. The heat sink 50 and the can 30 can be die cast or fused such that a hermetic seal is formed between the heat sink 50 and the can 30. The can 30 may be formed of any suitable metallic material, for example stainless steel, brass, bronze, or other suitable metallic material. The heat sink 50 may be formed of any suitable material conducive to casting, for example but not limited to, brass. In some embodiments, the heat sink 50 can be formed of a brass material having high thermal conductivity and high corrosion resistance, such as brass alloy C85800, though other suitable brass material may be used. The heat sink 50 may also be welded to the can 30 or, in some embodiments, may be silver soldered to the can 30 to form the LED module housing 53.
As indicated above, the heat sink 50 forms the base of the LED module housing 53. More specifically, the heat sink 50 is formed to have a mounting surface 52 exposed on the bottom inner surface of the LED module housing 53 and the lower portion 51 that extends from beneath the can 30 (see
LEDs 54 are mounted on the mounting surface 52 of the heat sink 50. LEDs 54 may be provided on printed circuit boards (“PCB”) that are subsequently mounted on the mounting surface 52 of the heat sink 50. In some embodiments, the LEDs may be mounted directly onto the mounting surface 52. For example, as shown in
The LED module 14 can also include a reflector assembly 56 that may be positioned within the LED module housing 53 over the LEDs 54. The reflector assembly 56 may be secured within the LED module housing 53 via fasteners, for example screws 57, though other suitable fasteners may be used. The screws 57 can be received in openings 59 in the heat sink 50. The reflector assembly 56 may comprise injection molded plastic, glass, or other suitable materials.
The reflector assembly 56 includes reflectors 60 that align with discrete LEDs 54 when the reflector assembly 56 is positioned within the LED module housing 53. In some embodiments, the reflector assembly 56 may have a single reflective surface that reflects the light emitted by all of the LEDs 54. The reflectors 60 can be rendered highly reflective. For example, in some embodiments, a surface of the reflectors 60 can have a surface reflectivity in the range of about 96% to about 99.5%, inclusive and more preferably in the range of about 98.5%-99%. The reflectors 60 can be comprised of any reflective material known to those of skill in the art as being suitable for reflective optics, including, but not limited to, polished metals (e.g., polished aluminum), MIRO 4, and reflective coatings (e.g., reflective paints).
Other embodiments of the reflector assembly 56 are contemplated, including for example the reflector assembly 80 shown in
An additional embodiment of a reflector assembly 90 is shown in
The LED module 14 can also include a lens 34 positioned and secured over the reflector assembly 56. The lens 34 will be exposed when the fixture is in use and thus should be formed from a material having suitable strength and integrity to withstand the rigors of use (e.g., foot traffic, heat, chemicals, corrosion, etc.). In some embodiments, the lens 34 may be formed of glass or polymeric materials. The lens 34 can be a clear flat lens but may be provided with any optical enhancements to create the desired lighting effect.
A gasket 62 is provided around a perimeter edge of the lens 34 to seal the LED module 14. The LED module 14 may also include a retaining ring 64 and a clamp band 66 for further sealing the lens 34 to the LED module housing 53. During assembly, the lens 34 is positioned on the lip 32 of the can 30. The retaining ring 64 is positioned to lie on the gasket 62 and the clamp band 66 wrapped around the lip of the can 32 (as well as the edges of the lens 34/optional gasket 62) and optional retaining ring 64 so as to sandwich those components between the clamp band 66. The clamp band 66 can be tightened by drawing the ends of the clamp band 66 closer together, for example via a screw. In this way, the clamp band 66 secures the lens 34 together against the lip 32 of the can 30 to hermetically seal the LED module 14. Prior to sealing the LED module 14, it may be desirable to use a “dry air purge” process to eliminate moisture from being trapped within the sealed LED module 14 during assembly and thereby prevent condensation on the internal surface of the lens 34.
The light fixture 10 further includes a finishing piece 16 that is secured onto the fixture housing 12 over the LED module 14 (see
The finishing piece 16 will typically have a shape that generally corresponds to the cross-sectional shape of the fixture housing 12. In this illustrated embodiment, the finishing piece 16 has a generally circular shape. The finishing piece 16 is provided with a central opening 35 for receiving the lens 34 of the LED module 14.
Apertures 38 are provided in the finishing piece 16. The apertures 38 can be in fluid communication with the openings 22 of the support ring 18 such that fluid and gas, for example water and air, can pass through the apertures 38, flow through the openings 22 of the support ring 18, and enter the interior cavity 23 of the fixture housing 12.
The apertures 38 of the finishing piece 16 can be of any suitable shape, size, and number for providing fluid communication between the apertures 38 and the openings 22 of the support ring 18. For example, as shown in
After the LED module 14 has been positioned in the fixture housing 12, the finishing piece 16 is then secured onto the fixture housing 12 and over the LED module 14. When so secured, the apertures 38 of the finishing piece 16 at least partially align with the openings 22 in the support ring 18 to permit air and water to enter the fixture housing 12, pass through the interior 23 of the fixture housing 12, and exit the fixture housing 12 via the lower openings 40 in the fixture housing 12. In use, air and water can pass through the apertures 38 in the finishing piece 16 and the openings 22 in the support ring 18 to enter the interior of the fixture housing 12. The lower portion 51 of the heat sink 50 is exposed to such air and water such that the heat from the LEDs 54 that has been conducted to the heat sink 50 is convectively dissipated from the heat sink 50 by the air and water moving through the fixture housing 12. The water and air may then exit the fixture housing 12 via lower openings 40. The exposure of the heat sink 50 to the air and water that may pass through the fixture housing 12 can enhance the convective and conductive cooling of the heat sink 50. The enhanced convective and conductive cooling of the heat sink 50 can enable the use of higher output LEDs in the LED module 14 while continuing to effectively manage and dissipate the increased heat associated with higher output LEDs. Because the LED module 14 and the power module 70 are each hermetically sealed, their operation is not compromised by water passing through the fixture housing 12 of the light fixture 10. Moreover, such movement of water and air through the fixture housing 12 helps to flush particulates and contaminants (sand, dirt, mud, etc.) that may have accumulated within the fixture housing 12.
Thus, an improved in-grade light fixture is disclosed. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the claims. Rather, different arrangements of the components described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the invention.
This application claims the benefit of U.S. Provisional Application No. 62/183,531, filed Jun. 23, 2015 and entitled “IN-GRADE LIGHT FIXTURE,” the entire contents of which are hereby incorporated by reference.
Number | Date | Country | |
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62183531 | Jun 2015 | US |