Patent Application
20080186717
1. Field of the Invention
The present invention relates to a compact in-grade or in-ground luminaire. More particularly, the present invention relates to an in-grade luminaire for outdoor commercial lighting or larger residential lighting.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
While this invention is capable of embodiments in many different forms, multiple embodiments are shown in the figures and will be herein described in detail. The present disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiments illustrated.
Referencing initially
The invention may be powered by one of several voltage and frequency combinations either alone or in electrical communication with one or more other luminaires. The luminaire 100 may contain a light source of various types, but the wattage of the light source is approximately 400 watts. The design of the invention is such that the temperatures inside the luminaire 100 are within safe operating limits as determined by third party safety agencies, including Underwriters Laboratories (UL). The invention may contain internal and/or external luminaire accessories including, but not limited to, rock guards, directional shields, directional louvers and source shields. The enclosure 110 is generally cylindrical in shape. An upper portion of the enclosure 110 has a first larger diameter. The second lower portion of the enclosure 110 has a smaller diameter. The middle portion of the enclosure 110 tapers between the upper and lower portions. However, such description should not be considered limiting of the enclosure shape.
The luminaire enclosure 110 provides approximately 1750 cubic inches of air volume within it, part of which is used to house the internal components of the luminaire 100. The unused air volume inside the luminaire enclosure 110 provides the means for distributing heat, via convection, to cooler areas of the enclosure 110. Although this specific volume is described, it is only exemplary and should not be considered limiting.
In one embodiment, the luminaire enclosure 110 is covered by a glass lens 156. The exemplary glass lens 156 is formed of tempered molded borosilicate although alternative materials may be used. The glass lens 156 is secured by a lens ring 158, which may be made of, but not limited to, brass or stainless steel. The lens ring 158 is located in a seat defined by an upper generally peripheral portion of the enclosure 110. However, such construction is not limiting. The lens ring 158 is attached to the luminaire enclosure 110 by fasteners of a suitable type. The lens 156 can be held in place by use of compression limiter pads on the lens ring 158, which aid in preventing the lens ring 158 from being tightened too tightly against the lens 156. If the lens 156 is over tightened, cracks or breakage could result. The compression limiter pads restrict the amount of compression on a main lens gasket 159, which ensures a positive seal. The main glass lens 156 seals against the luminaire enclosure 110 by use of the main lens gasket, which in one embodiment is made of silicone, between the two components.
A wiring compartment 160 may be attached to a side of the luminaire enclosure 110. In one embodiment, the wiring compartment 160 is square and is large enough to hold wires used to make electrical connections. The wiring compartment cover 163 may be made from a brass or stainless steel sheet to provide an aesthetic match with the lens ring 158 or an external accessory. The wiring compartment 160 may attach to the luminaire enclosure 110 through fasteners of a suitable type or may be integrally formed with the enclosure 110. The wiring compartment 160 may further comprise a lower conduit aperture 161.
When the luminaire enclosure 110 has a wiring compartment 160, the luminaire enclosure 110 is approximately 14¾ inches at the narrowest part of the top (across the glass lens 156) and 17¾ at the widest part of the top (across the glass lens and wiring compartment 160). The overall height is approximately 19¼ inches excluding any external accessory. However, these dimensions are merely exemplary and should not be considered limiting.
The luminaire enclosure 110 may be molded from a thermal plastic material with molded-in cavities where the lens ring 158 and wiring compartment cover 163 are attached by fasteners of a suitable type. Exterior ribs 165 extending approximately halfway down the luminaire enclosure 110 provide additional structural rigidity to the enclosure 110. The luminaire enclosure 110 may also have an external wiring channel 164 on the enclosure 110 extending down from the wiring compartment 160 to enclose the wires on three sides. Wires extend down from the wiring compartment 160, pass through the wiring channel 164 and may engage a socket connection inside the luminaire enclosure 110. Such technology is shown and described in U.S. Pat. No. 7,011,436, which is incorporated by reference herein.
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As previously discussed, the lamp module bracket assembly 168 of
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Referring now to FIGS. 1 and 7-9, the lamp module assembly 170 is enclosed by means of a lamp module band 126. The lamp module band 126, or C-shaped closure band, holds the lamp module lens 155 against the reflector gasket and the reflector 130. The closure band 126, depending on construction, may also hold an internal accessory as well as the parts previously mentioned. A latch 128 at the open end holds the components together when it is secured into the latch opening on the other side of the open end. In order to apply the latch 128, the band 126 must be compressed so that both ends of the open area move towards one another, which allows a hook portion 129 of the latch 128 to connect with the latch opening. The compressive force on the band constricts against the reflector gasket, which ensures that the band 126 does not bend too much. Once the latch 128 is secured and the band 126 is released, the reflector gasket expands back to its normal shape. This expansion helps to enlarge the open area of the band 126, which further enables a positive lock of the closure band 126. The process for installing and removing the closure band 126, especially beneficial for replacing the light source, is toolless and provides a convenient method to enter the lamp module assembly 170. It should be noted that this description discusses the use of two rings in the lamp bracket assembly 168, but actual construction is not limited and could use more, less, or none for operation of the luminaire. Further, it should also be noted that in at least one embodiment, the lamp module lens 155 may be removed as well as the lamp module band 126. Such embodiment is referred to as a single lens luminaire or fixture.
Referring now to
Referring now to FIGS. 1 and 5-8, a lamp module assembly 170 is depicted. The lamp module assembly 170, which comprises a reflector 130 and the lamp housing 132, fits in the luminaire enclosure 110 and contains the light source or lamp 154. The lamp module assembly 170 is connected by the cordset 134a to the ballast assembly 138. The lamp module assembly 170 comprises a lamp housing 132 and the reflector 130. The lamp housing 132 may be made from molded thermal plastic material with threaded inserts molded thereon for attaching fasteners. The lamp housing 132 may also be molded from other materials. A hole is located near the bottom of the lamp housing's 132 side wall, which is where the ballast assembly's cordset 134a connects to the lamp module assembly 170.
The reflector 130 is made from spun aluminum and may additionally have segmented specular sheet aluminum and is mounted directly on the lamp housing 132. The reflector 130 may be chemically treated to produce a diffuse or specular finish. The reflector 130 mounts to the lamp housing 132 by sitting on a gasket 133 that cradles the upper edge of the lamp housing 132 and is secured in place by fasteners that attach to some of the lamp housing's molded-in inserts.
A socket assembly 172 sits in the bottom of the lamp housing 132, and a lamp 154 may be screwed or otherwise inserted into the socket assembly 172. The reflector 130 may extend approximately six inches above the lamp housing 132. The reflector 130 acts as the upper portion of the lamp module assembly 170 and does not need to be enclosed in another enclosure.
The upper edge of the reflector 130 incorporates a flange where a reflector gasket is attached. This reflector gasket, for single lens fixtures, rests on top of the lamp module bracket assembly 168 without being secured so that the lamp module assembly 170 can rotate about a vertical axis or pivot about a horizontal axis with movement of the lamp module bracket assembly 168. The reflector 130 design differs depending on the desired light output such as spot, flood or wall wash. The socket assembly 172 comprises a socket 144 and, depending on the fixture version, a socket plate that helps thermally isolate the socket 144 and receptacle's wiring from the rest of the lower housing. A secondary thermal plate or plates helps to further thermally isolate the socket and receptacle's wiring from the rest of the lower housing.
For applicable fixture versions, a clear flat lamp module lens 155 sits on the top side of the reflector gasket and is secured to the reflector 130 by a lamp module band. The lamp module band 126 may be made from spun aluminum metal with a break in the band so that it can be opened and placed around the reflector's flange and the lens. A metal tab or latch 128 that is welded to the lamp module band 126 latches the open section of the band 126 together and holds it closed. For these fixture versions, this lamp module band 126 rests on top of the lamp module bracket assembly 168 without being secured to the lamp module assembly 170 so that the lamp module assembly 170 can rotate inside the lamp module bracket assembly 168.
The optical designs for the lamp module assembly 170 demonstrate a way to produce desirable amounts of light by not being constrained to having a reflector inside the housing; rather, the reflector 130 can be directly attached to the lamp housing. This provides a means of light output control while still enclosing the lamp components inside. This construction method allows for cooler lamp operations as well. The air volume inside the lamp module assembly 170 is maximized by making the reflector 130 part of the lamp module assembly 170.
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Another method for removing heat from the ballast assembly 138 was to utilize an epoxy resin in the ballast assembly 138 that dissipates heat well. The exemplary epoxy resin utilized is Innovative Resin Systems EP288, which draws the heat away from the ballast and other components to ensure that they run cooler and more efficiently. Additionally, the epoxy resin needed to have a filler media that would keep the ballast assembly 138 cost effective and maintain the thermal conductivity provided by the epoxy resin. The media that was eventually chosen as optimal for this epoxy resin was number 3 unground silica sand having a grain fineness of 5. Sand provides a high thermal conductivity value so that the overall thermal conductivity of the ballast module assembly is maintained at a desired level. The low viscosity of the epoxy resin requires grain size of the media to be of concern because too small a grain size would prevent the epoxy resin from filling air spaces in between the sand. The viscosity of the epoxy resin helped dictate that the number 3 size was ideal based on these concerns. The ballast components were changed to a class “N” insulation system for a better insulation material to keep heat away from the path of electricity.
The ballast is encapsulated with an epoxy resin. There is a ¼″ inch gap 166 between the ballast in one compartment and the capacitor and ignitor in another compartment. The epoxy again selected is Innovative Resin Systems EP288 (tradename). The resin draws the heat away from the ballast and the heat dissipation characteristics, and in addition to its ability to withstand high temperatures, was only found with this particular compound. No other epoxy resins on the market were available that could meet these requirements. To our knowledge, this ballast assembly application is the first time this material has been used as part of a luminaire product. This description is illustrative and other resins and materials that perform equally well may be used and therefore may be considered equivalents or alternatively the resin and media could be eliminated as other higher performance enclosures become available.
In addition, the cordsets 134 connected to the ballast assembly 138 needed to be fabricated from higher temperature materials to withstand the increased heat inside the luminaire 100. The custom-manufactured Conxall® quick-connect cordsets 134 utilize standard connector and overmold parts that are molded from high temperature nylon material, while the cordset cable is high temperature Teflon cable. Extensive testing was run to ensure that these cordsets would meet all of the demanding requirements for this high heat application. These materials were selected although such description should not be limiting as other materials may be used.
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The thermal barrier plates 146, 150, of the socket assembly 172 allow more wattage to be placed into a smaller enclosure and to keep the additional heat (from conduction as well as convection) away from electrical component wiring. The lamp 154 produces a considerable amount of heat. Measures needed to be taken to make sure that heat does not affect the wires within the socket 144.
The socket 144 sits on two thermal barrier plates 146, 148 that help lessen the heat that contacts the socket's wires. The first plate 146 underneath the socket 144 is an aromatic polyamide polymer, which reduces thermal conduction from the socket 144. The plate 146 is specifically a synthetic aromatic polyamide polymer low density pressboard sheet (trade name Nomex type 992), which was chosen because it has one of the lowest thermal conductivity values available for non-metallic materials. A second plate 148 underneath the socket 144 is a stainless steel sheet, which was chosen due to the fact that stainless steel has one of the lowest thermal conductivity values of commercially available metals. The stainless steel plate 148 serves to add rigidity to the design and serves as a means to secure the socket 144 without additional fasteners via threaded tapped holes. The wires of the socket 144 pass through the middle of these two plates 146, 148 during assembly so that the convection heat on the wires is greatly minimized. One embodiment of the invention utilizes a secondary thermal barrier plate 150, which is made from the same Nomex type 992 material and is spaced away from the first Nomex plate by standoffs 152 to achieve a useful air gap between them. The secondary thermal barrier plate 150 also partially shields the socket 144 from convective heat. Although materials for the plates 146, 148, 150 are specified, these descriptions should not be considered limiting as alternative materials may be utilized.
When the air temperature around the lamp 154, wiring and other electrical components increases, a cyclical process starts where the components heat up and they become less efficient (i.e. more electricity is converted into heat), which in turn causes the air temperature surrounding the components to heat up further, which then causes the components to heat up, causing a thermal runaway situation. A balance between the air temperature and component temperature must be maintained to assure that the life of the components won't degrade quickly.
The flood optical reflector produces a flood type lighting distribution utilizing a combination of convergent and divergent optical designs to prevent the center area of the lens from overheating. A typical flood optical design commonly utilizes the convergent, or elliptical, optical design that causes the radiant energy produced by the light source to converge at a focal point, which causes the center area of the lens to overheat. With a combination convergent and divergent optical design, the focal point is outside of the luminaire and spread out so that the radiant energy isn't focused to a spot that would overheat and cause a failure as well as inducing more heat into a product where heat reduction is a challenging task.
The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention and scope of the appended claims.
This application, under 35 U.S.C. § 119(e), claims priority to, and benefit from, U.S. Provisional Application No. 60/887,602, filed on Feb. 1, 2007, entitled, “Compact In-Grade Luminaire,” listing the above-referenced individuals as joint inventors.
| Number | Date | Country | |
|---|---|---|---|
| 60887602 | Feb 2007 | US |
