Abstract: A strobe alarm system which includes multiple normally self-timed strobe circuits connected in a common loop to a fire alarm control panel, and a sync control circuit, which may be incorporated in the fire alarm control panel, for causing the strobes to flash in synchronism at a predetermined rate which will insure that a person viewing the multiple strobes would not see flash rates higher than the predetermined synchronized rate, which is preferably less than five flashes per second. The sync control circuit does not interfere with the supervision functions of the alarm system, and when an alarm condition is present it supplies power to the strobe circuits which it then interrupts once every flash cycle to cause a sync trigger circuit in each strobe to fire its flashtube, and to reset the internal timer of each strobe to ready it for arrival of the next sync signal.

Abstract: A strobe alarm circuit includes a voltage source circuit which has a capacitor connected across its output terminals. The voltage source circuit is connected to a flash circuit which includes a flashtube shunted by a trigger circuit. The trigger circuit causes the flashtube to flash when the voltage across the voltage source circuit capacitor reaches a predetermined threshold firing voltage. A resistor divider network is employed in the trigger circuit to ensure that the flashtube is triggered at virtually the same instant as the voltage across the capacitor exceeds the trigger threshold value.

Abstract: A strobe warning light comprises an elongated strobe lamp having a longitudinal axis, a lamp support supporting the lamp in a predetermined position, and a reflector on the support that includes a first surface positioned on one side of a first reference plane that includes the lamp axis and a second surface spaced apart axially of the lamp from the first surface and positioned on the other side of the first reference plane. The first and second surfaces face generally toward each other and are configured and oriented to receive light from the lamp and reflect it in opposite directions along paths generally parallel to the lamp axis and on opposite sides of the first reference plane so that each one of the first and second surfaces directs reflected light predominantly past the other of the first and second surfaces. The reflector also has a third surface that is configured and oriented to reflect light from the lamp in divergent directions generally radially with respect to the lamp axis.

Abstract: A flashtube circuit includes a switch which in a first position regulates the storage over time of energy in a first energy storage device and in a second position allows the transfer of energy from the first energy storage device to a second energy storage device. A microcontroller receives the input voltage and then samples and digitizes it for input into a lookup table. The microcontroller repeatedly cycles the switch between flashes by controlling the time the switch is in its first position. The lookup table output provides the signal for determining the time the switch remains in its first position. The time interval from the last flash controls the time the switch is in its second position. The cycling of the switch is controlled accordingly such that the second energy storage device acquires the predetermined amount of energy for the flash just as the triggering circuit is initiated by the microcontroller.

Abstract: An interface for a supervised multiple input, audible warning system is disclosed. The interface continuously monitors or supervises a plurality of circuits between a control unit and an alarm unit for electrical faults. Each circuit represents a separate alarming condition. All the circuits are coupled to but normally isolated from each other and a common circuit for driving a piezoelectric device. The isolation is accomplished by means of a semiconductor switch normally reverse biased. The semiconductor switch prevents the supervising current of one circuit from driving the piezo by isolating all possible flow paths to all circuits without current flow in the alarming direction. Upon sensing an alarming condition, the direction of the current in the alarming circuit reverses resulting in forward biasing the semiconductor switch. The current in the alarming circuit, no longer isolated from the common circuit, actuates the common circuitry necessary for generating the audible warning.

Abstract: A strobe light of a type suitable for safety, notification, and intrusion systems and the like includes a base, a lens having a generally cylindrical side wall defining an opening at one end, having an end wall at the other end and being attached at its open end to the base, and a lamp/electronics assembly mounted on the base and received within the side wall of the lens. The base has a generally planar main wall that is shaped and dimensioned such as to form closure for the opening of the lens side wall and having a front surface facing the end wall of the lens and a rear surface facing away from the end wall of the lens. A generally centrally located mounting boss having a threaded socket is adapted to receive a threaded mounting member.

Abstract: A strobe light circuit for flashing a flashtube at a desired frequency includes a transformer the primary of which is repetitively connected and disconnected across a D.C. power source by a switch so that energy stored in the primary winding during closed periods of the switch is transferred to the secondary winding of the transformer, with a step-up in voltage, during open periods of the switch, and through a diode to an energy-storing capacitor connected in parallel with the flashtube.

Abstract: A strobe alarm circuit utilizing an optocoupler in the DC-to-DC converter portion of the circuit for repetitively connecting and disconnecting an energy-storing inductor across a DC power source. The light-emitting diode portion of the optocoupler is connected in parallel with a resistor connected in series with the inductor for continuously monitoring the current flowing through the inductor; when the inductor current has attained a particular value at which the voltage drop across the resistor is sufficient to turn on the LED, the switch portion of the optocoupler is turned on and disconnects the inductor from across the source. After a short interval determined by the parameters of the optocoupler and associated circuitry, the cycle is repeated.

Abstract: A motor bell alarm comprises an electric motor and a linkage by which the rotational motion generated by an electric motor is translated to a longitudinal oscillating motion so as to cause a plunger coupled to the linkage to cyclically strike a shell, thereby creating a ringing sound. The volume and clarity of the ringing sound are enhanced by minimizing the time in which the plunger is in contact with the shell and by minimizing the rest mass that is in contact with the shell as it is struck by interposing a lost-motion connection between the plunger and the linkage to the electric motor, whereby upon and after striking the shell the plunger is mechanically uncoupled from the lever.

Abstract: An audiovisual signaling device includes in electrical connection: (a) an auditory output portion which produces an auditory output and a corresponding low voltage oscillatory signal; (b) a converter portion which is responsive to and converts the low voltage oscillatory signal to a repetitively produced corresponding high voltage intermittent spike signal; (c) a visual output portion which produces a visual output; and (d) a portion responsive to the high voltage intermittent spike signal to repetitively activate the visual output.

Abstract: An audio-visual alarm includes a flashtube and a voltage signal generator for producing and storing voltages sufficient to operate the flashtube. In series with the flashtube and the voltage generator is the coil of an audio alarm, whereby operation of the flashtube also operates the audio alarm. The audio alarm is selected so that its coil will not interfer with the operation of the flashtube.

Abstract: An automatic audible signaling system for use in emergency warning and direction of people in the evacuation of buildings and the like comprises control apparatus at a central station, a plurality of local amplifiers mounted at remote locations, and at least one loudspeaker connected to each amplifier. The control apparatus comprises an audio preamplifier and, coupled to the output thereof, a modulation transformer having a center-tapped secondary to which a DC voltage is applied when it is desired to operate the loudspeakers. This arrangement supplies mixed DC power and low-level audio signal voltage to each of the remote amplifiers and obviates both the use of a high-power amplifier at the central station and the transmission of a high-power audio signal from the central control apparatus to the remote loudspeakers.

Abstract: An audiovisual signaling device including an auditory signaling means, an inductor for energizing the signaling device, and a circuit interruptor in series circuit with the inductor. A flashtube is electrically connected to the inductor and interruptor, and the inductor acts as an electromagnet when a voltage is impressed across the inductor and interruptor. The series circuit is intermittently interrupted by the interruptor, and the flashtube is actuated in response to the decaying magnetic field of the inductor when the circuit is thus interrupted.

Abstract: A grille for protecting a loudspeaker or the like comprises two substantially identical parts, each part being formed with bars defining a plurality of openings. When the two parts are placed together in back-to-back and head-to-toe relation, the openings in one part are out of register with the openings in the other part. This provides a plurality of circuitous paths through the grille for the passage of sound or the like, but there are no straight-line paths through the grille for the passage of vandalizing implements or the like.

Abstract: The transmitter of a fire-alarm audible signaling system permitting selective communications and signaling transmits digital command signals to receiver-drivers respectively positioned in a number of fire zones over a single two-wire or three-wire circuit that also provides power to the receiver-drivers. Each command signal includes a frame bit, a zone designator comprising, say, four bits and a function designator comprising, say, three bits. The frame bit is always a one and is always the first bit of the command signal, and it serves as a reference. A comparator in each receiver-driver compares an identification code proper to that receiver-driver with the zone designator of each command signal, and each receiver-driver responds to the function designator of a command signal to perform the designated function only in case of a match between the zone designator of the same command signal and the identification code for that receiver-driver.