Abstract: A magnetically operated display element having contrasting opposite sides, is symmetrically mounted in a surrounding frame for pivoting about an axis. A permanent magnet within the display element has poles on opposite sides of the pivoting axis. A U-shaped electromagnet has its pole pieces positioned on opposite sides of the pivoting axis where they may interact with the poles of the permanent magnet. The permanent magnet has a asymmetrical magnetic construction relative to the pivoting axis. When the electromagnet is energized, the repulsion at one pole of the permanent magnet is always greater than at the other pole of the permanent magnet, causing rotation of the display element. The display element is statically and dynamically balanced.

Abstract: An arrangement and method for providing an elongated light source, such as for illuminating a sign or the like or for other display, which includes emitting light from an exterior light source into an inner tube having a portion lined with a high reflectance film of prismatic lenses, the tube having a light-transmitting opening along its length, with a diffusing medium substantially diametrically opposite such opening, and optionally a reflector at one end of the inner tube. The inner tube is concentrically surrounded by an outer tube having light-transmissive portions of different colors. The outer tube is rotatable relative to the inner tube. The emitted light propagates in the inner tube by reflecting from the high reflectance lining and the reflector to impinge on the diffusing medium and thereby transmit light outwardly through the light-transmissive opening and thereafter through a selected one of the colored portions so as to project colored light against a sign or like object.

Abstract: A method of fastening and a fastening assembly are disclosed, where a nut may be retained in a grooved channel by a resilient retainer. The retainer has a central portion with an opening in registry with the threaded opening of the nut and also has two wings extending in opposite directions outward from the central portion. The wings have sharp edges to grip into the channel. A tool with projections is used to disengage the wings from the channel and permit the assembly to be slid along the grooved channel to a desired position. Upon withdrawal of the tool, the sharp edges of the wings resiliently grip into the channel to releasably retain the nut in the channel.

Abstract: A fixture for a fluorescent lamp includes a diffuser panel. The diffuser panel has a frame and longitudinal elements supported by the frame and spaced apart from one another. At least some of the elements are constructed of a material to allow diffusion of impinging light. Preferred materials are translucent or transparent, such as glass or plastic. The diffuser panel also functions as an air diffuser. Provision of a nozzle in the base of the fixture allows air to flow through the panel by a sucking effect created by high velocity forced air flowing through the nozzle. This results in fixture cleaning and temperature equalization. The fixture is particularly adapted to be mounted in a moving vehicle. For this purpose, the panel is designed to be tamper-resistant and to provide easy maintenance. The diffuser panel, when a latch is opened, may be lowered by rotation to provide access to the lamp and ballast.

Abstract: A field telephone system having a widely dispersed set of telephone lines including a page line pair and a party line pair, audio processing equipment including telephone handsets, handset amplifiers, receiver amplifiers and paging speaker amplifiers is designed to have improved voice transmission by provision of a narrow band FM carrier system. The FM carrier system includes a device for generating a carrier frequency signal, a modulator for modulating the carrier frequency with an audio signal derived from one of the handsets at a transmitting station and circuitry for transmitting the modulated signal over a line pair to a receiving station. The receiving station includes circuitry responsive to the transmitted signal and the carrier frequency signal for extracting the audio component of the transmitted signal and for processing the extracted audio signal and for providing the processed audio signal to a handset at the receiving station.

Abstract: In an improved strain gage for measuring pressure differentials within areas of varying pressure there is provided a flexible sapphire diaphragm having disposed thereon a Wheatstone bridge. The diaphragm being attached to a base portion by way of a glass bonding material. The base portion's function being to support the flexible diaphragm without interfering with the measurement of strain. The diaphragm having a recess extending to a predetermined depth thereby defining a recessed area having a peripheral edge in order to create pressure points at the peripheral edge of the recess adjacent the recessed area of the diaphragm.

Abstract: A circuit for delivering a predetermined amount of energy to a load without regulating the voltage across the load is described. An a.c. or rectified sine wave is controlled. There is no capacitive smoothing of the applied voltage. A time counter is activated at the beginning of each half cycle of the sine wave. At a predetermined point in time, a switch is closed and power is delivered to the load. At another predetermined time in the same half cycle, the actual applied voltage is measured. The detected voltage value and corresponding time of measurement comprise a unique signature enabling identification of the specific sine function for that half cycle. The sine function signature permits calculation of either the amount of total energy delivered or the RMS voltage level as a function of progressing time, and thus, determination of the time period for which the line switch must remain closed in order to deliver the predetermined amount of total energy, or to maintain a predetermined RMS voltage.

Abstract: A method for etching sapphire and other etch-resistant materials is disclosed. The method consists of preparing a hot, precipitated-gel form of phosphoric acid solution and immersing the item to be etched in the hot, precipitated-gel. The gel is prepared by heating a liquid phosphoric acid solution, causing water contained in the solution to evaporate. As the water evaporates, the solution thickens and eventually attains the precipitated-gel state. The etching rate of a sapphire wafer immersed in the gel is on the order of 10-50 microns per hour, depending on the depth of immersion, the orientation of the wafer and the temperature of the gel.

Abstract: A directional coupler transformer insensitive to data bus termination failures, includes a ferrite toroid core about which first through fourth windings are wound, the first and second windings being for connection in series with each conductor, respectively, of a data bus for sensing or generating data signal current, the third winding being connected in parallel with the data bus conductors for sensing or generating data signal voltage, and a fourth winding inductively coupled to the other three windings for either coupling data signals traveling in one direction from the data bus to a receiving unit, or coupling data signals from a transmitting unit to the data bus for transmission along the data bus in a given direction.

Abstract: A thermal print pulse controller and data shifter accomplishes control of a thermal print pulse by altering the pulse width of the print pulse according to the printing history. Data is obtained from the printhead and recirculated for logical operation with previous records back to the printhead during predetermined phases of the print pulse. As a result of the logical comparison a decision is made to continue or discontinue printing of a dot and thus prevent overheating the printing element.

Abstract: In a display where all characters are displayed in equal sized spaces, such as a bus or vehicle sign, for example, the problem of characters appearing to merge from a distance is remedied. The spacing between characters is automatically adjusted in accordance with both the characteristics of the particular character representations displayed and their sequence within the display.

Abstract: A thermal print head for use in thermal printing apparatus has a pattern of conductive lines for energizing a resistive member overlying a portion of the lines to generate discrete heated spots on the resistive member. A screen-printed protective coating over a portion of the pattern is adapted to reduce the abrasive effect of grit particles carried on the medium to be printed. The coating comprises a layer of dried and fired material formed of a ceramic/glass overglaze composition mixed with fine metallic oxide particles.

Abstract: A method of screen printing a conductive ink onto a substrate to form a pattern of narrow, closely spaced conductive lines. Before screening, the conductive ink is exposed to ambient air until its viscosity is in the range 700,000 to 900,000 centipoise at 70.degree. Fahrenheit.

Abstract: A memory transfer unit is provided which permits replacing messages stored in a message display system with a different set of messages stored in the memory transfer unit. A circuit is provided for supplying power from the message display system to the memory transfer unit and for inhibiting operation of the memory transfer unit unless the power supply to it has a proper operating voltage level. Pulses produced in the message display system are counted to determine the sequential locations of data in the memory transfer unit to be transferred to the message display unit for substitution for data stored in the message display unit.

Abstract: A linear air diffuser is disclosed for the delivery of conditioned air to the interior of a passenger vehicle such as a bus, railcar or the like. The diffuser consists of a frame structure characterized by a pair of open ended longitudinally extending delivery channels situated in a generally parallel side-by-side relationship. Each of the channels is turned to extend laterally outwardly in opposite directions and is provided with a curved interior surface on one wall to intercept input air so as to induce eddy currrent turbulence in the flow characteristics of the delivered air. The input openings to the channels are partially closed by a common longitudinal plate releasably affixed to the frame structure. The lateral peripheral edges of the plate serve to determine the width of a narrow longitudinal input orifice for each of the channels.

Abstract: A transducer operating on the strain gauge principle having integral temperature compensation and calibration resistors is disclosed. In the presently preferred embodiment, a silicon dioxide layer is disposed on a silicon substrate. Platinum alloy strain gauge resistors are disposed on the silicon dioxide layer and form a Wheatstone bridge circuit configuration. Laser trimable chromium nitride, platinum alloy and gold temperature compensation and calibration resistors are formed on the silicon dioxide layer from the same films used to form the strain gauge, adhesion layers, conductors and bonding pads, to permit the transducer to be calibrated such that its electrical characteristics are in conformance to specified tolerances when the transducer is subjected to temperature variations.

Abstract: A high voltage, pulse width regulator circuit wherein the input voltage may be up to twice the voltage rating of pass or switching transistors used in the circuit is disclosed. This is accomplished by dividing the input unregulated DC voltage or full wave rectified AC voltage in half. The divided voltage is placed on each of two input lines. The pulse width regulator utilizes two transistors or other semiconductor switches, each receiving one half the input voltage. To insure a properly regulated voltage on the output and to avoid the possibility of one of the transistors receiving more than one half the input voltage, means are provided for insuring that the voltage drop across either transistor will be limited to approximately one half the input voltage at all times. By utilizing the teachings of this invention, a pulse width regulator capable of handling an input voltage of at least twice the rating of the transistors employed in the regulator is obtained.

Abstract: A linear air diffuser is disclosed for the delivery of conditioned air to the interior of a passenger vehicle such as a bus, railcar or the like. The diffuser consists of a frame structure characterized by a pair of open ended longitudinally extending delivery channels situated in a generally parallel side-by-side relationship. Each of the channels is turned to extend laterally outwardly in opposite directions and is provided with a curved interior surface on one wall to intercept input air so as to induce eddy current turbulence in the flow characteristics of the delivered air. The input openings to the channels are partially closed by a common longitudinal plate releasably affixed to the frame structure. The lateral peripheral edges of the plate serve to determine the width of a narrow longitudinal input orifice for each of the channels.