Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-01-25
2001-01-30
Hofsass, Jeffery A. (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S691100, C340S693600, C362S147000, C362S259000, C040S540000, C040S560000
Reexamination Certificate
active
06181251
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to smoke detectors, and more particularly to a smoke detector that provides a laser beam to guide people to an exit when there is a fire.
DESCRIPTION OF RELATED ART
Smoke detectors are well known in the prior art; and two examples of modem smoke alarms are provided in U.S. Pat. Nos. 4,827,244 to Bellavia, and 4,166,960 to Meili. Typically, smoke detectors simply provide an audible alarm to alert people nearby that there is a fire.
Improved smoke detectors not only sound an alarm when smoke is detected, they also activate powerful lights or flashing strobes to help direct people to an exit. Frank, U.S. Pat. No. 4,649,376, for example, discloses the use of powerful flashing Xenon lamps to pierce smoke and direct people to the exit. Other examples of this technology are described in U.S. Pat. No. 4,148,023 to Elkin, 4,570,155 to Skarman, and 4,763,115 to Cota. While these devices can be useful in some circumstances, the flashing incandescent lights can tend to daze and confuse rather than direct, especially in a smoky room where it may not be apparent where the flashes of light are originating. Furthermore, intense flashing lights destroy night vision, often causing more harm than good to confused people trying to escape a dark building. To appreciate the problems inherent in this technology it is useful to understand that Xenon lamps are used in flash bulbs. It is easy to imagine having flash bulbs flashed in one's face while trying to escape a burning building in the dark—they may confuse rather than guide. None of these references disclose the use of lasers or pulsed lasers, which have properties entirely different than non-coherent lights.
Cota, U.S. Pat. No. 4,763,115, further discloses the use of a redundant circuit that is activated by a central audio alarm to trigger the smoke alarm and slashing circuits. While this is a useful feature, it does not disclose the use of a network of lasers to activate a plurality of smoke detectors as well as light a path through a building to an exit.
The state of the art is disclosed in U.S. Pat. Nos. 5,572,183 to Sweeney, and 5,140,301 to Watanabe. Sweeney, U.S. Pat. No. 5,572,183, discloses a device that sweeps a laser beam across a plurality of mirrors. Each mirror directs the laser beam into the floor at a different location, thereby “walking” that apparent laser beam towards an exit. Watanabe, U.S. Pat. No. 5,140,301, discloses a centrally controlled network that generates a laser which is guided and oscillated by a controlling mirror. Neither of these devices disclose a battery operated device that is self-contained within a housing that can be installed to form a comprehensive fire escape network. None of the prior art devices can be easily installed and adjusted in the place of traditional wall or ceiling mounted smoke detectors. And none of these devices teach the use of a pulsed laser to provide directional information to people attempting to escape a fire.
The present invention fulfills these needs and provides further related advantages as described in the following summary.
SUMMARY OF THE INVENTION
The present invention teaches certain benefits in construction and use which give rise to the objectives described below.
The present invention provides a combination smoke detection device and laser escape indicator. The combination includes a primary circuit that electrically connects a power source to a laser. The primary circuit has a smoke detector switch that is operably controlled by a means for detecting smoke. When the smoke detecting means detects smoke, it closes the smoke detector switch, thereby activating the laser to produce a laser beam. The laser is mounted on a means for pointing the laser in a desired direction. When the combination is installed in a structure, the laser is manipulated so that when the laser generates a laser beam, the laser beam will point towards a preferred exit from the structure. The primary circuit is preferably also connected to a siren, so when the laser is triggered, an audible siren is also activated, providing people within the structure with a warning of the fire.
A primary objective of the present invention is to provide a combination smoke detection device and laser escape indicator having advantages not taught by the prior art.
Another objective is to provide a smoke detection device that is self-contained, battery operated, and internally adjustable to project a laser beam towards an exit without the use of external directional devices.
Another objective is to provide a smoke detection device having a pulsed laser, the pulsed laser producing a pulsed laser beam whose movement can be perceived by people and followed to the exit.
A further objective is to provide a smoke detection device having a means for pointing the laser beam that is easy to install, adjust, and maintain.
Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
REFERENCES:
patent: 4148023 (1979-04-01), Elkin
patent: 4199754 (1980-04-01), Johnson et al.
patent: 4489308 (1984-12-01), Logan, Jr. et al.
patent: 4570155 (1986-02-01), Skarman et al.
patent: 4649376 (1987-03-01), Frank
patent: 4763115 (1988-08-01), Cota
patent: 4801928 (1989-01-01), Minter
patent: 4808977 (1989-02-01), Hedrick
patent: 5140301 (1992-08-01), Watanabe
patent: 5572183 (1996-11-01), Sweeney
patent: 5594410 (1997-01-01), Lucas et al.
patent: 5612665 (1997-03-01), Gerhardsen
Hofsass Jeffery A.
Karich Eric
Pham Toan
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