Abstract: A mailbox indicator and lid closure system that includes a flag indicator mounted from a support plate of the container and connected by way of a cable to a bracket supported on the lid. Opening the lid causes the indicator to be pulled by the cable to the upright position thus indicating that mail has been delivered. A spring is connected between the container and lid to ensure that the lid remains open while mail is being delivered.

Abstract: A bi-directional storage and dispensing system is for accommodating cables, cords, tubes, hoses, and other similar mediums. The system includes a hollow container; a smaller diameter tube positioned within the container; and a pair of covers at either end of the container for holding the tube within the container while being removable.

Abstract: An analog and digital data-gathering system where the data gathering remote device or sequencer units are serially connected such that initially only the device closest to a control unit is powered and other data-gathering devices in the system are sequentially switched into circuit as each such remote device or sequencer unit responds to polling signals from the control unit. The system initially measures the signal from the wiring to a remote device or sequencer unit without the device being activated in order to determine the noise level present in the circuit wiring. The corresponding remote device is then activated by being interrogated or polled after that noise level has been determined.

Abstract: In a digital power amplifier, a high frequency linear modulated driving signal is used to control a bridge circuit arrangement of transistors. By inputting this high frequency linear modulated signal to a bridge arrangement of driving comparators, a controlled dead band is created and a balanced output is obtained from the bridge circuit arrangement of transistors. The balanced output signal is then fed through a filter circuit for demodulation. An alternative embodiment of the invention employs a bridge circuit consisting of transistors connected in parallel for improved power handling capabilities.

Abstract: A fault tolerant control system employing input sensing network and in association therewith a signal processing system which eliminates the effect of radiofrequency interference, electromagnetic interference, transients, and random false alarm signals. The sensing network comprises a linear circuit or a resistor disposed in parallel with one or more semiconductors which are preferably diodes or the like. The network senses current flow so as to provide a signal having a maximum voltage established by the semiconductors with the linear circuit or network providing a linear change in voltage with current until the voltage of the semiconductor is reached when the voltage then becomes non-linear.

Abstract: A combination optical and ionization detector for providing a more complete range of detection including detection of larger particles of combustion and smaller sub-micron particulates. Each detection channel (optical and ionization) may be independently calibrated and each has means such as an indicator light to identify which channel has alarmed. Each channel has detection circuitry for establishing both a pre-alarm condition and a full alarm condition. Differing alarm states are determined by the generation of audibly or visually distinguishable signals. For example a short signal may indicate a pre-alarm condition while a long, coded or modulated signal may indicate a full alarm condition. A further distinctive signal may indicate activation of two or more detectors. A supervisory channel may also be provided to detect, for example, circuit component failure.

Abstract: A technique for calibrating an ionization detector by simulating the presence of particles of combustion. In one embodiment a test probe is employed extending into the chamber. The probe may be partially conductive and partially non-conductive and be either rotatable or able to be withdrawn or partially withdrawn to vary ionization current. In another embodiment the source may be moveable to alter the ionization current. In still another embodiment there is provided the temporary distortion of one electrode to change the geometry of the chamber to thereby effect ionization.

Abstract: The smoke detector uses modulation techniques to differentiate within a smoke detection chamber between ambient energy and energy from a transmitting source. A delayed automatic gain control is provided to reduce the effects of slow change of parameters in the detector itself and to provide greater discrimination between smoke which should cause an alarm and smoke resulting from, for example, tobacco. The smoke detector further provides for increased signal-to-noise ratios thus providing for more accurate and precise measurements.

Abstract: The detector uses a single radioactive source, such as a beta ionization source, with a multiple chamber construction. The source is positionable relative to the center or node electrode to provide simple adjustment of ionization in each chamber of say a dual chamber detector. Adjustment may be achieved without altering the geometric volume of the chambers or electrode spacing, but instead by altering the ratio of the source area protruding into each chamber. In one embodiment the center or node electrode is fixed and the source is adjustable in a direction normal to the electrode or by tilting relative to the electrode. In another embodiment the source is fixed and the electrode is adjustable relative to the position of the source. The principles may also be embodied in a three-chamber detector.

Abstract: A pulsed or strobed smoke detector operable periodically in a pulsed mode. A strobe generator having minimum power consumption limits the time of power consumption by other elements of the detector to a fraction of continuously operating time. A storage circuit is also included to limit transient or start-up consumption of power.

Abstract: An ionization detecting fire alarm device that comprises a double chamber structure, a source disposed in at least one of the chambers and a vernier adjusting screw electrode protruding into one chamber. The chamber containing the adjustable electrode is more open to the atmosphere than the other chamber. Porting is provided between chambers and detection occurs by sensing the rate of change of ionization current in the chamber structure. The source or sources, one being in each chamber, is a beta source such as a nickel 63 source. A change in ionization current is detected by a unique circuit of this invention which comprises a programmable unijunction transistor oscillator circuit.

Abstract: An optical smoke detector for pulsed or continuous operation in which optical biasing of a light source and receiving transducer is employed to permit operation of the detector at points of greater sensitivity, stability and linearity than are found at low light levels. The optical biasing may be provided by a light-scattering optical integrator associated with the light source causing controlled impingement of light upon the field of view of the receiving transducer. Adjustment of the relative positions of the light source and transducer and of the disposition of a barrier between those elements as well as the holders of those elements provides further control of the optical biasing. The housing of the detector is provided with smoothly contoured passages for the unimpeded passage of smoke particles to an internal optical detection chamber.

Abstract: In an active system a transmitter transducer and a receiver transducer are both secured to an object such as a glass panel the intrusion through which is to be monitored. The transmitter transducer establishes a relatively low frequency signal in the panel and a supervisory branch which couples from the receiver transducer monitors the presence of this supervisory signal. A second branch which also couples from the receiver transducer is for monitoring intrusion and comprises digital circuitry including a pair of monostable multivibrators and a counter which counts pulses from one of the monostable multivibrations during a time interval determined by the other monostable multivibrator to discriminate between panel breakage and panel rapping, for example. The tampering with voltage lines is also detected and a special holder is employed for fastening the transducers to the panel.

Abstract: The operability of one or more audio speakers is monitored by continuously transmitting a non-audio signal on the lines connecting to the speakers and providing a vibration sensitive transducer such as a piezoelectric transducer which continuously picks up the signal. The output from the transducer couples to detection circuitry which may comprise an amplifier and gate or trigger circuit. The output of the detection circuitry couples either via the existing speaker lines or via a separate supervision line to an alarm device. When the speaker or speaker lines are inoperative the non-audio signal is not present and the gate circuit transmits an alarm signal to an alarm device. In one embodiment the detection circuitry is supplied power directly from the speaker lines via a rectifier means. In another embodiment the detection circuitry includes an oscillator, one associated with each speaker and each constructed to oscillate at a different frequency.

Abstract: An ionization detecting fire alarm device that comprises a double chamber structure, a source disposed in at least one of the chambers and a vernier adjusting screw electrode protruding into one chamber. The chamber containing the adjustable electrode is more open to the atmosphere than the other chamber, porting is provided between chambers and detection occurs by sensing the rate of change of ionization current in the chamber structure. The source or sources, one being in each chamber, is a beta source such as a nickel 63 source. A change in ionization current is detected by a unique circuit of this invention which comprises a programmable unijunction transistor oscillator circuit.

Abstract: The infrared system employs an optical focusing arrangement for collecting radiation from a moving object such as an intruder and directing the energy to a sensing element which may be a thermistor whose resistance changes with energy level change. The detection circuit comprises a biasing means comprising a voltage divider network in series with the sensing element and a modulator or oscillator circuit coupled to the sensing element. The modulated output signal from the sensing element couples to an impedance matching circuit which in turn couples to an amplifier. The output from the amplifier couples to a low frequency blocking filter for removing very low frequency components of the signal. From there the signal couples to an integrator and an output trigger alarm circuit. When sufficient energy is received by the sensing element the amplifier saturates and the modulating frequency disappears or is shunted. Once this occurs the trigger circuit is activated and an alarm condition prevails.