Building alarm system with synchronized strobes

• US 20040104811A1
• Filed: 11/21/2003
• Published: 06/03/2004
• Est. Priority Date: 09/24/1993
• Status: Active Grant

• Current Assignee: Tyco Fire & Security GmbH (Johnson Controls International plc)
• Original Assignee: ADT Security Services SA (Apollo Global Management, Inc.)
• Inventors: Stanley, Lawrence G., Stewart, Albert J.
• Granted Patent: US 7,005,971 B2
• Time in Patent Office: Days
• US Class Current: 340/326
• CPC Class Codes: G08B 5/36 using visible light sources
• CPC Class Codes: G08B 7/06 using electric transmission , e.g. involving audible and visible signalling through the use of sound and light sources

Abstract

In a building fire alarm system, the light strobes of a network of strobes are synchronized to flash simultaneously. Each strobe has a charging circuit to charge a capacitor which discharges through a flash tube. Once a capacitor is charged, the charging circuit is disabled. A synchronization pulse is applied through common power lines to trigger discharge of each strobe capacitor through the flash tube followed by recharging of the capacitor.

Claims

1. A method of synchronizing audible alarms and visual strobes comprising:

connecting the audible alarms and visual strobes to common power lines and applying power to the audible alarms and visual strobes through the common power lines; and

after the audible alarms and visual strobes have been powered, repeatedly changing the voltage on the power lines to control timing of the audible alarms and visual strobes.

2. A method as claimed in claim 1 wherein a change in voltage which triggers the strobes ends an audible beep.

3. The method of claim 1 further comprising powering the visual strobes to charge a capacitor in each strobe;

and wherein the step of changing the voltage on the power lines includes providing a synchronization signal through the power lines to cause each strobe to discharge the capacitor through a flash lamp in each strobe such that the strobes flash in synchronization with each other.

4. The method of claim 3 further comprising controlling timing of the strobes to provide an encoded visual output.

5. An alarm system comprising:

a pair of power lines;

at least one audible alarm powered by said power lines;

visual strobes powered by said power lines; and

means for applying power to the audible alarm and visual strobes through said power lines and repeatedly changing, after said power has been applied, said voltage on the power lines to control timing of the audible alarm and the visual strobes.

6. The system of claim 5 wherein the audible alarm is non-continuous and synchronized to the visual strobes.

7. The system of claim 5 wherein the means for changing voltage triggers the visual strobes and ends an audible beep.

8. An alarm system comprising:

a pair of power lines;

at least one audible alarm powered by a voltage on said power lines, the audible alarm being controlled by a change in the voltage on the power lines after power is applied; and

visual strobes powered by said voltage on said power lines, the strobes being repeatedly triggered to synchronously flash with a change in the voltage on the power lines after power is applied.

9. A system as claimed in claim 8 wherein the audible alarm is noncontinuous and synchronized to the visual strobes.

10. A system as claimed in claim 8 in which the change in voltage that triggers the strobes ends an audible beep.