Abstract: An optical fiber having a square or rectangular cross section provides one mode of optical signal transmission comprising reflection between one pair of parallel sides and a second mode between a second pair of parallel sides perpendicular to the first pair so that two separate channels are obtained in a single optical fiber. A transmitter and a receiver are coupled to each end of the optical fiber so that full time two-way communication can occur without substantial interference.

Abstract: A planar magnetron sputtering cathode assembly especially for simultaneously heating and coating substrates is also adaptable to a cool substrate operation. The cathode assembly features an efficient magnetic circuit using magnet assemblies enclosed within the sputtering chamber using minimal air gaps for magnetic efficiency and high-strength magnets to produce a high field at the sputtering target, and stainless steel cladding of the magnets to protect the magnets as well as to prevent out-gasing from the magnet material. A heat sink fills the space between the magnets to provide excellent cooling of the magnets as well as cooling of the target which seats directly on the heat sink. The target is held in place by bolts to facilitate rapid target changing.

Abstract: A low fuel indicator system 10 for a motor vehicle comprises a light-emitting indicator 12 which is energized or de-energized by an output signal derived from a voltage comparator 14 which receives a reference voltage from a reference voltage source 20 and a variable voltage signal from a time delay circuit 22, which variable voltage signal is derived from a voltage signal generated by a fuel level sensor in a fuel tank of the vehicle. The light-emitting indicator 12 is energized when the fuel level in the fuel tank falls below a predetermined low level, and time delay circuit 22 operates to isolate the voltage comparator 14 and light-emitting indicator 12 from temporary variations in fuel level produced by "fuel-slosh" in the fuel tank caused by variations in the motion or orientation of the motor vehicle.

Abstract: To measure the mass airflow into an engine having a manifold with a given volume, the mass airflow through an induction passage into the manifold is measured by a meter and the measured value is changed by an amount to compensate for changes of air density in the manifold. The manifold pressure and temperature are monitored and the correction value is calculated as where V is the manifold volume, R is a gas constant, T is the temperature and P is the air pressure in the manifold.

Abstract: A microwave probe for measuring the amount of soot or water in engine crankcase oil and/or detecting the level of oil comprises a coaxial cable having a tip including five substantially parallel wires shorted together at one end and connected at the other end to the coaxial cable, one of the wires being connected to the center wire of the coaxial cable and the other four wires being connected to the sheath of the coaxial cable. The size and geometry of the wires is selected so that the impedance of the tip when immersed in oil substantially matches the impedance of the coaxial cable.

Abstract: Low oil level in an engine crankcase is detected immediately after the ignition switch is turned on by a circuit including the ignition switch, an oil level sensor and a coolant temperature sensor wherein a control circuit generates an output if a low oil level signal is present when the ignition switch is turned on. An enabling circuit allows an output only if the ignition switch has been turned off for a sufficient time period to allow oil drain back to the crankcase. A time delay circuit responsive to coolant temperature and the ignition switch prevents a control circuit output after the ignition switch is turned off for a short period when the temperature is high and a long period when the temperature is low.

Abstract: During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld.

Abstract: In a resistance welding device wherein the welding gun is carried by a robot for rotation about a robot axis, an electrical slip ring assembly for carrying weld current to the weld gun also supports the rotary weld gun. Axially stacked collector discs insulated from one another are electrically and mechanically connected to separate bus members for connection to the weld gun and a pair of adapter plates for connecting the assembly to the rotary drive of a robot and to a weld gun respectively are all bolted together into a unitary rotary arbor assembly. Each collector disc presents a cylindrical outer surface and a nonrotating supply ring surrounds each disc and is connected to one terminal of a power supply. The supply rings are expansible and a fluid actuator operates each supply ring to clamp it tightly to its corresponding collector disc for good electrical connection and to release the ring from the collector disc to allow rotation of the arbor assembly.

Abstract: To measure the flushness and the gap width between adjacent spaced panels, a pair of light sources project beams of light onto the respective panels adjacent the gap at oblique angles to the panels to provide on each panel an illuminated region extending from the gap to a sharply defined boundary so that for a given position of the gap relative to the light beams outer margin the width of the illuminated portion of each panel transverse of the gap is a function of the position of each panel in relation to the light source and the relative positions of the outer margins depend upon the flushness of the panels. In the preferred form an electronic camera comprising a linear photodiode array receives an image of the illuminated pattern, the optics being such as to provide a sharp image within a predetermined range of flushness.

Abstract: Heat exchanger cores comprising an assembly of elongated vertical and horizontal parts are brazed by induction heating in a vacuum chamber where the magnetic heating field is disposed at an angle to the vertical and horizontal planes for uniform heating. Steel supports for strength and durability are used to hold the cores in the vacuum chamber. A pair of elongated steel fixtures engage opposite sides of each heater core, the fixtures having recesses at their outboard surfaces. A rectangular frame having a pair of support rods is held by brackets within the chamber to orient the plane of the frame parallel to the magnetic field to minimize electrical heating of the frame. The recesses in the fixtures engage the support rods of the frame in a manner to hold the vertical parts in a vertical plane and to prevent rotation of the core by action of the magnetic field on the core.

Abstract: During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld.

Abstract: A valve assembly is provided for a paint color change system for directing paint to spray guns from either of two supply lines selectively while connecting the other line to exhaust, and simultaneously controlling the paint pressure as a function of pilot air pressure. A valve block contains two pairs of poppet valves, each pair having a common inlet chamber connected to one of the paint supply lines and containing a pair of poppets each biased toward a seat for controlling flow to an outlet chamber, and a pilot air operated diaphragm in each outlet chamber coupled with a poppet for regulating the position of the poppet in accordance with the paint pressure in the outlet chamber and pilot air pressure.

Abstract: A hot element anemometer uses solid state diode chips for the heated air flow sensing element and the ambient temperature sensing element in parallel circuit branches. The air flow sensing element carries a heating resistor on the diode chip. Constant current sources of equal value supply current through the diodes. The air flow sensor diode is in series with a resistor which determines the nominal temperature difference between the diode chips. A circuit compares voltages in the two diode branches and provides an air flow output signal and controls the temperature of the air flow sensor diode. To compensate for changes of thermal conductivity of the air temperature and various temperature effects in the circuit, a third current source is coupled to the ambient temperature sensing branch through a resistor network and includes resistors that can be adjusted to provide a functional calibration which yields an air flow signal free of linear temperature effects.

Abstract: A color change system for supplying paint to a remote spray head uses a paint manifold and suitable valving for supplying paint to either of two supply lines extending to the spray head to enable one supply line to be flushed with cleaning fluid and filled with paint of a new color while the other line is supplying paint of another color. Part of the necessary valving is located at the spray head and that valving includes pressure regulating valves controlled by air pilot pressure to accurately regulate the paint pressure and thus the paint flow rate to paint spray devices.

Abstract: During a weld period the weld parameters are monitored and data representing the weld resistance curve and the power curve are acquired and stored for analysis by a suitably programmed computer. The derivative of R, R is calculated and stored and the function is divided by power P to obtain R/P. The resistance curve is searched to obtain the maximum value R.sub.m which occurs during the heating phase and the function R/P is searched prior to the time of R.sub.m to find the maximum of that curve representing the highest rate of resistance increase. Then the R/P curve is searched subsequent to its maximum to determine when the function reaches a specified percentage of the maximum. That value occurs at the knee of the resistance curve and approximates the onset of melting in the weld.

Abstract: Conductive particulates in the form of soot are collected from diesel engine exhaust gases on a porous wall monolithic ceramic filter in such a way that the soot is somewhat uniformly distributed throughout the filter. The filter is housed in a chamber having a property of a microwave resonant cavity and the cavity is excited with microwave energy. As the particulates are collected the cavity appears to the microwaves to have an increasing dielectric constant even though the matter being accumulated is conductive rather than dielectric so that as collected on the porous filter it has the property of an artificial dielectric. The response of the cavity to the microwave energy is monitored to sense the effect of the dielectric constant of the material within the cavity to provide a measure of the soot content in the filter.

Abstract: To evaluate the droplet evaporation and liquid/vapor phase interactions in aerosols and sprays, an optical method for measuring the concentration of the gas phase is provided. Two laser beams are passed through a mixture of the gas and liquid particles, one beam having a wavelength not absorbed by the gas and the second having a wavelength which is absorbed by the gas. Attenuation of each beam is measured, the droplet size distribution is measured by a light scattering technique and the concentration of gas in the path of the light beams is determined from the attenuation of each beam, the droplet size distributions, and known parameters.

Abstract: A twisted nematic liquid crystal cell is bounded by front and rear polarizers and a partially transmissive fluorescent color filter is placed behind the rear polarizer either as a coating on the polarizer or as a coating on a separate substrate. A light source behind the filter illuminates the display and ambient light incident on the face of the display provides illumination as well. The fluorescent filter enhances the light passing through the filter in a characteristic color band to provide a very bright display affording high contrast. Contrast is heightened by adding a small amount of pleochroic dye to the liquid crystal material. By using a plurality of colors in a predetermined pattern, the filter can provide a display illuminated in a variety of bright colors.

Abstract: Where airflow through a system is subject to forward and reverse flow, the mass airflow rate is determined by providing two flow branches A and B meeting at a junction wherein the two branches carry different proportions of airflow in the forward and reverse directions and branch B carries a greater fraction of the airflow during reverse flow than during forward flow. An airflow sensor in each branch measures the airflow irrespective of flow direction to obtain mass flow rate signals R.sub.A and R.sub.B for branches A and B, respectively. The mass airflow rate m is calculated from the equation m=K.sub.A R.sub.A -K.sub.B R.sub.B where m, K.sub.A and K.sub.B are constants for a given apparatus which are determined by each sensor characteristic and the flow characteristics of the junction. The resultant mass flow rate signal m will have a positive or negative sign indicative of forward or reverse flow.

Abstract: A pressure transducer of the manometer type comprises two interconnected columns of liquid with means for applying differential pressure across the columns. The liquid is a magnetic liquid and a magnetic field is impressed on the columns to attract the liquid by magnetic force to a reference position. The applied differential pressure acts counter to the magnetic force to shift the columns so that their difference in lengths reflects the pressure. By using capacitor plates to define the walls for the liquid columns and a magnetic liquid which is a dielectric, the capacitance between the plates is a function of the column lengths and therefore is a function of the applied differential pressure.