This invention pertains to lighting fixtures structured to dissipate heat from hot-running light bulbs and ballasts mounted in the fixtures and to prevent debris from unintentionally escaping from the fixtures.
Lighting fixtures used in gymnasiums or other sporting arenas, factories and other high-bay lighting applications or environments often contain hot-running light bulbs. These light bulbs produce a substantial buildup of heat in the lighting fixtures that can damage componentry including ballasts, refractors, housings, etc. The heat build up can also cause premature failure of the light bulbs. Because these fixtures are typically mounted well out of easy reach, maintenance is extremely difficult, so long life of the fixture and light bulbs is extremely desirable.
Oftentimes, such fixtures are provided with safety thermostats that cut off power to the light bulbs if certain safety limit temperatures are exceeded. While this may prevent damage to the fixtures and premature bulb failure, it is obviously undesirable since the lighted gymnasium, factory, etc. will go partially or completely dark in such circumstances.
Embodiments of the present invention prevent heat buildup in such lighting fixtures without interfering with the normal and expected appearance or operation of the lighting fixtures. They thereby improve fixture reliability and bulb longevity and minimize the chances of safety shut-off due to fixture overheating. Embodiments of the present invention also prevent the unintentional escape of debris from the lighting fixtures.
Turning first to
Fixture 10 includes a housing 12 with a housing opening 11 and a refractor 14 fitted to the housing opening. In alternate embodiments, the refractor may not be used and an enlarged housing may extend beyond the light bulbs 15.
As shown in
A second circular plate 32 of the same diameter as plate 22 is located above the axial fan and attached to plate 22 by a series of spacers (not shown) about its periphery. Plate 32 has a central aperture 33 aligned with aperture 26 and of approximately the same diameter as aperture 26. The fan is therefore sandwiched between plates 22 and 32 to form a fan/socket assembly 34.
A thermostat 36 may be mounted above ballasts 18 by bracket 19 which is affixed to the top of plate 32. Ballasts 18 are spaced apart as shown to facilitate airflow and hence cooling by the fan. The thermostat may be set to a predetermined temperature (e.g., 130° C.) to warn of imminent fixture failure due to overheating, for example by lighting a warning light or tripping an alarm (not shown).
Refractor 14 has a proximal opening 41 and a distal opening 50 and is positioned with its proximal opening 41 at housing opening 11. When refractor 14 is clear or translucent, some of the light produced by bulbs 15 is projected through the refractor. The proximal opening 41 at the top of refractor 40 is encircled by an annular edge 42. A circular retaining plate 44 is designed to sit below edge 42 to removably affix the refractor to housing 12 with the fan/socket assembly positioned in collar 24 at the bottom of housing 12. The distal annular opening 50 of the refractor is encircled by an annular collar 52. This collar facilitates attachment of a protective lens assembly 16.
Protective lens assembly 16 is positioned at the distal opening 50 of the refractor. As noted above, the protective lens assembly may be mounted within an enlarged housing when a refractor is not used. Lens assembly 16 comprises a bottom circular flat lens 56 and a top circular flat lens 59. While it is preferred that the bottom lens have a larger diameter than the top lens, both lenses may be of the same diameter or the bottom lens may have a smaller diameter than the top lens.
Although bottom lens 56 is illustrated with an axially positioned circular opening 60 which is preferably larger than the diameter of openings 26 and 33, other opening shapes may be used and the opening(s) need not be centrally located. Lenses 56 and 59 are spaced from each other by pins 62 which are arranged along the periphery of lens 59 and are attached at either end to the two clear or translucent lenses, forming a first ventilation gap 64. While any appropriate spacing could be used, the spacing preferably will be no greater than about one inch. The combination of lenses blocks direct access to the interior of the housing so that, inter alia, (1) objects cannot move into the fixture from below and damage components within the fixture; and (2) components within the fixture cannot fall through the lens assembly and escape the fixture.
The outer edge of top lens 58 is spaced from the border of the distal opening 50 of the refractor to form a second ventilation gap 55 allowing an air stream A to pass between the edge of the top lens 58 and the border of the distal opening 50 of the refractor (as shown in
A protective wire grid 70 is located below bottom lens 56 to protect the lens and the interim of the fixture from damage for example in a gymnasium or athletic arena setting. The wire grid also protects people below the lighting fixture, like the lens assembly, from debris that might come loose in the fixture, for example, from a broken light bulb.
Finally, an annular flexible locking band 72 with an opening 74 held together by a spring 76 and top and bottom annular lips 77 and 78 is provided to capture and hold the lens assembly and the protective grid at the bottom of the refractor along collar 52.
Once in place, the lens assembly facilitates air flow through the fixture to prevent it from overheating while also preventing any broken light bulbs or other debris from escaping the fixture and falling onto spectators or others disposed below the fixture.
Lighting fixture 10 operates as follows:
Thus, the invention makes it possible to move air through the fixture to cool it without impairing its ability to prevent debris from escaping through the bottom of the lighting fixture while also safeguarding the interior of the fixture.
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. It should be understood that the illustrated embodiments are exemplary only, and should not be taken as limiting the scope of the invention.
This patent application claims the benefit of U.S. Provisional Patent Application No. 61/334,905 filed May 14, 2010.
Number | Name | Date | Kind |
---|---|---|---|
4321659 | Wheeler | Mar 1982 | A |
4546420 | Wheeler et al. | Oct 1985 | A |
4939374 | Greutert | Jul 1990 | A |
7380965 | Nakashita | Jun 2008 | B2 |
20030185012 | Sitzema et al. | Oct 2003 | A1 |
20050243539 | Evans et al. | Nov 2005 | A1 |
Number | Date | Country | |
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20110280021 A1 | Nov 2011 | US |
Number | Date | Country | |
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61334905 | May 2010 | US |