Patent Grant
7845972
The present invention relates to the field of lampholders and more specifically to screw-base ceramic lampholders used in recessed lighting fixtures for general lighting in residential, institutional and commercial buildings.
Over recent years here has been an ever-increasing need for energy conservation in general lighting for residential, institutional and commercial buildings. One of the means for saving lighting energy has been the replacement of inefficient A-type incandescent lamps with tungsten/halogen lamps having about twice the L/P (lumens per Watt) or with CFL (Compact Fluorescent Lamps) having three times more lumens per Watt than A-type incandescent lamps.
In order to use tungsten/halogen lamps or CFL lamps in light fixtures that are recessed above a ceiling, UL (Underwriter's Laboratories) and various building codes require high-temperature ceramic lampholders, over 90% of which are for medium screw-base lamps. Then, in order to obtain a safety listing under UL standard1598 for a recessed light fixture, the fixture must have a thermal cut-off switch as well as the high-temperature ceramic lampholder. The purpose of the thermal switch is to prevent the lamp heat from burning the insulation off the wiring inside the fixture, which would create a possible electric shock hazard.
Prior to the present invention, 3-way lamps were used only in unenclosed portable lamps, such as table lamps and floor lamps with the light sources cooled by ambient air. Thus, prior to the present invention, all 3-way lampholders were made of polymeric materials, such as Bakelite®, or had a brass outer housing with conductors and the screw shell insulated with plastic-impregnated paper.
At the time the present invention was made, the applicant contacted the major lampholder manufacturers, G. E., Osram-Sylvania and Leviton, plus distributors and retail outlets; and found there were (and still are at the date of this filing) no 3-way ceramic lampholders available from any manufacturer. This prohibits the use of 3-way lamps that permit changing lamp output (and energy consumption) to match the usage and weather conditions of a building.
Further, presently known prior-art recessed light fixtures, even those using single-circuit ceramic lampholders, are required to have a thermal switch, which is attached somewhere on the metal fixture housing. Therefore the wire insulation could be damaged before the thermal switch reached a typical tripping temperature of 90° to 100° centigrade. Thus the thermal switches of prior-art recessed fixtures do not serve the basic function of protecting the wiring from damage.
Since there were no available commercial prior-art sources for 3-way ceramic lamholders, or lampholders having integral thermal switches, or lampholders having integral cooling fins, the lampholder of the present invention was designed, developed, prototyped and tooled by the applicant, to be available only by sale or licensing by the applicant.
The first purpose purpose of the present invention is to save electrical energy by providing a ceramic lampholder that will permit the use of 3-way lamps in recessed light fixtures. With currently-available power (or with CFLs equivalent power) of 30-60-100 Watts, the 30 Watt level (about 500 lumens) would be more than adequate for lighting open areas, aisles and corridors; the 60 Watt level (about 900 lumens) is adequate for computer or other electronic display tasks, and the 100 Watt level (about 1950 lumens) is appropriate for detailed visual tasks such as small assembly work, reading and hand writing. Exceeding the appropriate light levels will not only waste energy, but excessive brightness can actually cause glare that reduces vision.
The second purpose of the present invention is to increase light fixture safety by providing a ceramic lampholder for 3-way lamps or single-circuit lamps, in which the lampholder includes an integral thermal switch that will disconnect if the fixture overheats due to improper ventilation. or the lamp exceeds the maximum rated fixture wattage.
The third purpose of the present invention is to increase lamp life by providing a ceramic lampholder that reduces the lamp electrode seal temperature and hence the differential glass-to-metal seal temperatures that most often cause lamp failure.
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The first above-stated purpose of the present invention is achieved by providing a ceramic lampholder that will save electrical power by permitting the use of 3-way lamps in recessed light fixtures and using only the lamp Watts needed for each specific function and task.
The second purpose of the present invention is achieved by providing a ceramic lampholder that will improve light fixture safety with an integral thermal switch that will disconnect if the fixture overheats due to improper ventilation or the a lamp that exceeds the maximum rated fixture wattage.
The third purpose of the present invention is achieved by providing a ceramic lampholder that will increase lamp life by reducing the lamp electrode seal temperatures that most often cause lamp failure.
The fourth purpose of the present invention is achieved by providing a ceramic lampholder that will decrease assembly costs and reduce fixture toxicity by eliminating all solder connections.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2505518 | Benander | Apr 1950 | A |
| 4682276 | Miller | Jul 1987 | A |
| 5263874 | Miller | Nov 1993 | A |
| 5514006 | Getselis et al. | May 1996 | A |
| 7223002 | Miller et al. | May 2007 | B2 |
