Abstract: A piezoelectric signaling device that produces a predetermined number of audio signals when activated. The device includes a timer, a pulser, an audio oscillator, and a piezoelectric transducer. The timer enables the pulser for a predetermined time. While enabled, the pulser produces pulses at a predetermined rate, thus producing a predetermined number of pulses. The oscillator is enabled during the pulses to produce a predetermined number of pulses of audio frequency electrical oscillations which are applied to the piezoelectric transducer to produce the predetermined number of audio signals.

Abstract: A switch is mounted on a plate within a housing having a housing body with a port and a removable housing cover. A switch actuator rod is mounted on a pivot within a sleeve that may be coupled to the housing so that the rod extends through the port and engages the switch within the housing. A linear actuator rod is slideably mounted within a sleeve which also may be coupled to the housing so that the rod extends through the port and engages the switch. A spring is mounted on the housing cover in a direction traverse to the arc through which the swing actuator rod pivots so that it engages the end of rod and biases it away from the switch. By removing the cover, moving the rod to the opposite end of its arc, and replacing the cover, the direction of engagement of the rod with the spring may be changed. The switch plate is movable along the rod's arc of pivot so that the switch trip point along the arc may be adjusted.

Abstract: A fire panel includes a housing with a rectangular opening and rectangular door covering said opening. The door is attached to the panel with a attaching elements which comprises a pair of tracks spanning the opening, each track having a t-shaped channel, and a pair of truss-headed screws attached to the door. The heads of the screws slide in the channels in the tracks permitting the door to be slid from one side of the opening to the other without detaching the door from the housing. The door permits ease of service while meeting Underwriter's Laboratories safety requirements.

Abstract: A radio frequency (r-f) transmitter has an electric oscillator circuit for producing an oscillating r-f signal in an antenna. A feedback sub-circuit of the oscillator circuit includes a surface acoustic wave (SAW) resonator for stabilizing the oscillations. The feedback circuit has a Q of less than 12000. There is a modulation sub-circuit of the oscillator circuit which includes a voltage variable capacitor. The voltage variable capacitor responds to input voltage variations to modulate the capacitance of the feedback circuit, thereby modulating the frequency of the transmitter. A garage door opener system employing the transmitter is also disclosed.

Abstract: A life safety system for monitoring a building has a plurality of detectors for detecting alarm conditions located throughout the building, a plurality of speakers located throughout the building, a source of pre-stored voice messages which can be broadcast over the speakers, and a telephone network. The improvement is a voice synthesizer for providing the source of pre-stored voice messages and a constant volume telephone system. The constant volume telephone system has a telephone line and a plurality of telephones which can be connected to the telephone line, and a power supply having an adjustable output voltage which provides the voltage for the telephone line. A sensing and adjusting circuit senses the number of telephones off-hook and causes the power supply to be adjusted in response to the number of telephones off-hook.

Abstract: A detector for sensing the presence of polar fluids includes a pair of detection probes and a circuit for providing an oscillating voltage across the probes. A power supply for the detector includes a transformer with a split secondary, with at least one secondary having a floating ground. One of the probes is connected to the floating ground. The other probe is connected to the input of a fluid detection logic circuit. The input is applied to an inverter having an activation threshold of approximately six volts. The resulting activation threshold of the detector circuit is sufficiently low to be activated by the oscillating voltage so as to produce a polar fluid output signal when the probes are immersed in a polar fluid, but sufficiently high so as not to be affected by stray voltages induced in the probes by conventional power lines, such as 120 VAC lines, contacting the polar fluid.

Abstract: Di octyl phthalate (DOP) is used as a dielectric fluid for a-c electrical capcitors. An additive of an epoxidized linseed oil in an amount from 0.1% to 30% by weight of DOP stabilizes the capacitors and thus prolongs their life.

Abstract: A machine controller having start and time delay functions activated and set by a single switch. There is a cycler for activating and deactivating machine functions in a timed sequence. There is a manually operable start/delay-set switch and an electronic circuit responsive to the switch which produces a start signal upon initial closing of the switch, and which produces a delay signal after the switch is held closed for a predetermined time. An electronic control circuit responds to the start and delay signals to store a delay time and activate the cycler after the stored delay time has expired.

Abstract: A security system having one or more sending units for transmitting a digitized r-f signal representative of a condition such as fire, smoke, intrusion, battery condition, an emergency, or other condition to a central receiving unit. The sending units include a microcomputer which Manchester encodes the data. The receiving unit includes a microprocessor which samples the data signal 24 times per data bit. The moving average of the 12 most current samples is calculated and differentiated into a high or low value depending on the value of the previously calculated averaged value. The time between data transitions (from high to low or low to high) is evaluated and then stored as being a long (1) or a short (0) time since the previous transition. When all the data has been received, the stored values for length of time between transitions are checked for conformance to the transition timing requirements of Manchester encoded signals. Signals without the proper timing are discarded.

Abstract: A powder of a film-forming metal, such as tantalum, is combined with a binder of polyethylene oxide and ammonium carbonate. The powder-binder combination is pressed to form an anode body and then heated to about 300.degree. C. for about 4 hours to remove the binder. The polyethylene oxide is a superior binding agent producing anodes of high porosity and strength. The ammonium carbonate reacts with liquid polyethylene oxide to release large quantities of gas which sweeps the polyethylene oxide out of the anode pores, resulting in an unusually small amount of binder residue and yielding capacitors with low d.c. leakage.

Abstract: Two thermistors are mounted in a fluid detection probe, one thermistor having its surface exposed to the ambient fluids, and the other encapsulated in an insulator, such as RTV, that has a thermal conductivity greater than air. The thermistors are connected in a resistance bridge circuit between ground and a positive digital circuit voltage, which circuit applies power to the thermistors, heating them. The side of the thermistors toward the positive voltage is connected to the inputs of a comparator. When air is present, the encapsulated resistor cools more than the exposed one and, therefore, the encapsulated resistors resistance is higher producing a higher voltage at its comparator input than the exposed resistor. In the presence of a liquid, the RTV insulates its thermistor from the cooling effect of the liquid, and its comparator input voltage is therefore lower than the voltage of the exposed thermistor comparator input.

Abstract: A fluid detection system capable of displaying the conditions in the environs of a large number of fluid detection probes and correlating each condition with the particular probe that detected it. There are a plurality of probes, each having a comparator preset with a unique probe identifier, such as a binary number. A counter produces digital signals representative of the binary numbers. The probe comparators are responsive to the numbers outputted by the counter and are connected to the probe power circuitry. When each comparator receives the signal corresponding to its preset number, it triggers its associated probe to produce status signals. A display circuit responds to both the number output by the counter and the probe status signals to simultaneously display the probe number and an indication of probe status.

Abstract: A system for detecting fluid pollutants includes probes for sensing the presence of a polar liquid, a non-polar liquid, and a dry condition, and for producing a polar liquid signal, a non-polar liquid signal, and a dry condition signal. A reference circuit which includes a tunable element, such as a variable resistor, is used to set the probe output signals to a predetermined voltage value: e.g. a 1-volt value indicates a polar liquid, a 2-volt value indicates a non-polar liquid, a 3-volt value indicates a dry state, and a 5-volt value indicates that the circuit is on and operating. The output signals are multiplexed and output on a single output line. The definitive signal levels and the serial output mode permit an inexpensive single channel recorder to be used to provide a permanent and complete record of the probe status.

Abstract: A metallized film capacitor having a dielectric fluid comprising glyceryl triacetate and about 30 to 90 vol. percent of epoxidized soybean oil.

Abstract: An internally threaded insert having intersecting faces about its axis is positioned in a keyed aperture formed in a cover for a capacitor. This provides an antitwist characteristic between the insert and the walls of the aperture to facilitate a seal between the two. An electrical terminal can then be threaded into the insert to electrically connect it to an internal lead of the capacitor.An elastic bushing is also carried in the keyed aperture to provide a seal.The cover has a rib extending around its periphery to engage a capacitor housing, the rib providing a seal.

Abstract: There are three oscillator circuits which oscillate at different frequencies, each oscillator circuit including a gate having an input and an output. The output of the first gate is connected to an inverter and the input of the second gate. The output of the inverter is connected to the input of the third gate. The output of the second and third gates is connected across a piezoelectric transducer to produce a warble sound.

Abstract: A dielectric fluid for a metallized film capacitor consisting essentially of glyceryl triacetate and 0.01 to 10 weight % of a hindered phenolic antioxidant of N,N'-bis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionyl] hydrazine. The capacitor body includes metallized polypropylene film forming the electrodes and a separating dielectric.

Abstract: A dielectric fluid for a metallized film capacitor consisting essentially of 75 volume % glyceryl triacetate and 25 volume % 3,4-epoxycyclohexylemethyl-3,4-epoxycyclohexane carboxylate. The capacitor body includes metallized polypropylene film forming the electrodes and a separating dielectric.

Abstract: There are three spring blades held in working relationship to a camstack which provide the making of two different and distinct circuits simultaneously by substantially simultaneously closing electrical contacts carried by the blade. Of the three blades a lower level blade engages cam contours of the camstack, a middle level blade includes a follower which engages a hub portion of the camstack, while the upper level blade extends freely above the middle blade.

Abstract: An audio signalling device provides a housing having at least one end, a piezoelectric transducer, a nodal mounting for the piezoelectric transducer in proximity to the end of the housing, a planar member, a mounting for the planar member in a spaced adjacent relationship with the piezoelectric transducer, and spring contacts mounted on the planar member for making spring biased electrical contact with the piezoelectric transducer.