Photography – With object illumination for exposure – Variable intensity control
Reexamination Certificate
1999-11-24
2001-10-30
Gray, David M. (Department: 2851)
Photography
With object illumination for exposure
Variable intensity control
C396S206000, C340S331000
Reexamination Certificate
active
06311021
ABSTRACT:
The present invention generally relates to an alarm unit. More particularly, the invention is a strobe alarm unit having a plurality of selectable candela settings or intensity levels, thereby allowing an alarm installer to select a particular candela setting for the alarm unit in the field for a particular application.
BACKGROUND OF THE DISCLOSURE
Strobe lights have been widely employed in warning systems such as fire warning systems, security systems and the like. In fact, various governmental regulations and/or standards, e.g., from the American Disability Act (ADA) and the Underwriters Laboratories (UL), have been established to define various requirements, e.g., strobe frequency and light output.
One important requirement is the light output of a strobe alarm unit for a particular application. For example, UL has adopted standards that require certain levels of light output from strobe alarm units for fire safety warning systems. Depending on a particular application and/or the location where the strobe alarm units are mounted, light output may range from 15 candela to 110 candela. In response, manufacturers of strobe alarm units have provided different models of strobe alarm units with each model having a specified light output to meet a particular application. For example, a ceiling mounted strobe alarm unit may have a particular light output intensity that is different from a wall mounted strobe alarm unit.
Although manufacturers are able to meet these different light output requirements by offering different models of strobe alarm units, such multitude of different configurations of strobe alarm units increases manufacturing cost and complexity. For example, different components for different models of strobe alarm units must be purchased and stocked as inventories. Different manufacturing lines must be operated and maintained. A single engineering modification may result in multiple changes across all configurations of strobe alarm units. Customer orders must be carefully tracked and filled in accordance with request for different models of strobe alarm units.
On the customer side, an alarm installer must also carefully mount the correct strobe alarm unit with a particular light output to meet the requirement of a particular application. If an installer incorrectly mounts strobe alarm units for a particular application or strobe alarm units with the wrong light intensity are received, the installer may face a substantial loss in time in having to reinstall the alarm units or to wait for the proper replacement of strobe alarm units to arrive. Such cost and inefficiency can be eliminated if the intensity level of the strobe alarm unit can be selectively set in the field.
Therefore, a need exists in the art for a strobe alarm unit having a plurality of selectable candela settings or intensity levels, thereby allowing an alarm installer to select a particular candela setting for the alarm unit in the field.
SUMMARY OF THE INVENTION
The present invention is a strobe alarm unit having a plurality of selectable candela settings or intensity levels, thereby allowing an alarm installer to select a particular candela setting for the alarm unit in the field. The strobe alarm unit incorporates a voltage doubler circuit that allows a single storage capacitor to provide the necessary discharge voltage across the flashtube to provide the plurality of selectable candela settings.
REFERENCES:
patent: 4853600 (1989-08-01), Zeltner et al.
patent: 4900990 (1990-02-01), Sikora
patent: 4951081 (1990-08-01), Hosomizu et al.
patent: 5019805 (1991-05-01), Curl et al.
patent: 5570077 (1996-10-01), Swieboda
patent: 5694118 (1997-12-01), Park et al.
“Select a Strobe Series” American Security Equipment Company,National Fire Protection Association Tradeshow, Baltimore, MD, May 16, 1999.
“Wall & Ceiling: Select a Strobe” American Security Equipment Company,National Fire Protection Association Tradeshow, Cincinnati, Ohio, May 17, 1998.
“Flashtubes”EG&G Heimann Optoelectronics Catalog, pp. front and back pages and selected pages, 1991.
Gray David M.
Moser Patterson & Sheridan LLP
Wheelock Inc.
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