Abstract: A diesel electric locomotive has a dynamic braking system including a plurality of traction motors connected across dynamic braking grids. Air blowers for cooling the grids have motors which are connected across the grids. The failure of any motor is detected by monitoring the voltage across the motor with respect to a reference potential. The reference potential is developed in a bridge arrangement wherein the bridge imbalance is detected by a current sensor or by a reference potential generated in another motor circuit where another current sensor is used to detect a variance from the reference value. A circuit responsive to failure signals but voltage isolated from the traction motor circuits actuates an indicator as well as a relay for diminishing or terminating the dynamic braking function.

Abstract: Resonant optoacoustic cells are used in measurements of the concentration and composition of a gas or aerosol. Such apparatus is improved by providing a small absorption cell acoustically coupled to a resonant acoustic cavity so that the time delay associated with the flow of a gas or aerosol through the absorption cell is greatly reduced.

Abstract: A variable capacitor includes a metal diaphragm arranged to flex in response to an applied pressure differential serving as a movable capacitor plate and a fixed capacitor plate closely spaced from the diaphragm. At least one of the two capacitor plates has an insulating layer of metal oxide formed thereon to prevent electrical contact therebetween. By making the capacitor plate of an iron-chrome-aluminum alloy and heating the capacitor plate, an aluminum oxide layer is formed thereon. The fixed capacitor plate is formed in a hat-shaped configuration with the brim portion spaced far from the diaphragm by an insulating spacer to minimize the fixed capacitance around the edge of the capacitor assembly.

Abstract: A welded lap joint is made in sheet metal panels by folding over the margin of one panel to form a U-shaped section and to crimp within the U-section a sheet metal spacer strip thereby producing a three layer configuration. The margin of a second panel is formed into an offset by an amount equal to the thickness of the three layers of the U-shaped section of the first panel. The offset margin of the second panel is spot welded to the bent over margin of the first panel using a conventional welding electrode bearing against the margin of the second panel and an electrode of large load distributing area contacting the top surface of the first panel so that the weld nugget formed between the margins of the two panels is isolated by the spacer from the surface of the first panel to avoid weld marking of the surface. The resultant product comprises first and second panels in the same plane and separated by a very small crevice. The crevice, if desired, may be filled with a filler material such as a plastisol.

Abstract: In a coherent optical correlation system for detection of object images at unknown angular orientations, a holographic spatial filter in the transform plane of the system is rotated until a correlation beam is produced. The spatial filter is mounted on a rotating cylinder which carries a first mirror placed in the path of the correlation beam emitted from the filter and disposed to direct the beam toward the axis of rotation of the cylinder and a second mirror on the axis and intercepting the beam for directing the correlation beam substantially along the axis. A motor drives the cylinder about its axis and an optical encoding device associated with the rotating cylinder provides an electronic indication of the cylinder orientation at any given instant.

Abstract: An industrial robot for spray painting workpieces carried by a conveyor is provided with a control to allow the programmed robot sequence to proceed synchronously with conveyor movement so long as the conveyor maintains a normal speed. When, however, the conveyor stops, the control maintains robot operation until the spray gun is moved to a safe stopping place to avoid excessive paint application to a portion of a workpiece. Upon conveyor start-up, the robot remains stationary until the workpiece approaches normal speed and moves into a position synchronous with the robot position.

Abstract: A circuit is provided for detecting an open condition in a thermocouple or thermocouple leads connected to a preamplifier even though the thermocouple is grounded or connected to ground through some resistance. A high frequency AC test signal is applied to both leads of the thermocouple and one of the leads is connected to a low pass filter. When the thermocouple circuit is closed, the AC signal on both leads will be substantially equal. If, however, either of the leads or the thermocouple itself is open, the AC signal will be different due to the low pass filter connected to one of the leads. That filter attenutes the signal on the associated lead as well as causing a phase shift of the two AC signals. A differential amplifier connected to the thermocouple leads detects the amplitude attenuation or the phase shift to provide an output whenever the thermocouple circuit is opened.

Abstract: The bulk temperature of the gas in a piston engine during combustion is determined by detecting the high frequency pressure oscillation in the combustion chamber operating the engine to produce knock and measuring the frequency of the lowest frequency mode of the high frequency knock signal. The frequency or inversely the period of that signal is a function of the gas temperature.

Abstract: A mechanism mounted adjacent one end of a roller bearing carries a probe biased against ends of the rollers, the probe having a shoe wide enough to span at least two rollers. A spring biased hammer is latched in a cocked condition by a latch device which is controlled by the probe. A bell or sounder rotates in a path near the hammer. When the cage of the bearing fails prior to bearing failure, the rollers bunch up forming a gap which allows the probe to drop into the gap to unlatch the hammer which swings against the bell to cause an audible indication of imminent bearing failure.

Abstract: A resistance welding electrode is formed of a hollow shank carrying current and cooling fluid and an electrode head connected to the shank by a flexible housing of insulated material. The housing forms a chamber to contain the cooling fluid supplied through the shank. The flexibility of the housing allows the head to rock relative to the shank and also to move axially away from the shank under the influence of the pressure of the cooling fluid. When welding pressure is applied through the electrode to a workpiece, the shank is forced against the head to provide firm electrical engagement between those elements.

Abstract: A collimated beam of light is directed onto a face of a microcircuit chip. If the configuration side of the chip is up and if the chip has a typical pattern predominantly comprised of two orthogonal sets of lines, the light reflected from the chip will be formed in a cross shaped diffraction pattern with most of the light concentrated in the center of the cross. If, however, the chip is upside down so that a plain face is exposed to the light, the light will be reflected fairly uniformly from the chip. By measuring the reflected light in a small center zone as well as in a larger zone and the light measurements are compared, it can be determined whether the diffraction pattern is present thereby revealing whether the chip is right side up, i.e. configuration side up.

Abstract: An engine output shaft is bolted to the hub of a drive plate or flex plate, the outer periphery of which is fastened to the torque converter of an automatic transmission such that the engine torque is transmitted by the drive plate from the engine to the transmission. An arcuate array of slots extending between the hub and the periphery of the drive plate define a plurality of spokes which carry the torque. The spokes bend or flex by an amount which is proportional to the torque. A pair of electromagnetic pickups are secured to the engine adjacent the inner and outer ends of the spokes respectively in order to obtain a measure of the spoke deflection and, therefore, of torque. A torque signal is electronically derived from the output of the pickups.

Abstract: A system for limiting the speed of a gasoline engine includes a circuit responsive to the engine speed which provides control signals to a solenoid valve which in turn controls a vacuum actuator. The vacuum actuator then overrides a manual throttle control to move the throttle toward closed position when a governed engine speed is approached. A control circuit provides a signal having four components; one proportional to engine speed, second and third proportional to engine acceleration and a fourth which is the integrated difference between the engine speed and a preset governed speed. In addition a speed switch actuated when an overspeed condition occurs is effective to inhibit the third component and to increase the fourth component to its maximum value to effect maximum governing action and system stability. The control signal controls a duty cycle oscillator which actuates the solenoid valve.

Abstract: A low tire pressure detector and magnetic signal sending unit includes a bellows charged to a reference pressure for moving a magnet from a shielded position to a signal emitting position when tire pressure operating outside the bellows decreases to a predetermined value. A latching force is established by the magnet to operate against the bellows force to help maintain the magnet in the shielded or non-signalling position. The magnitude of the latching force is controlled by a polepiece of thin cross section which saturates under the influence of the magnet to limit the latching force to a fixed value. The spring force of the bellows is sufficient in the absence of a pressure differential to overcome the latching force and move the magnet to signalling position. A ferrous slug mounted on the movable end of the bellows is magnetically coupled to the magnet assembly to form a releasable connection between the magnet assembly and the bellows.

Abstract: In a system having a pressure sensor on a vehicle tire for generating a magnetic field when tire pressure reaches a predetermined value, an indicating circuit includes a stationary reed switch which is closed when subjected to the magnetic field, a coil in series with the reed switch which develops a magnetic flux when the switch closes to latch the switch closed, and an indicator lamp in series with the reed switch which is continually illuminated when the switch is closed to provide a low tire pressure warning. A test circuit energized when the vehicle ignition key switch is in "start" position includes a pulse forming circuit for generating a current pulse in the latching coil to close the reed switch and provide an indicator light if the indicator circuit is operative.

Abstract: A nematic liquid crystal display device exhibits dielectric anisotropy when the device is in a normal operating temperature range. By placing electrodes on either side of the layer of liquid crystal material and applying across the material an electric field insufficient to change the molecular orientation in the material, the capacitance and therefore the dielectric constant of the material is measured. A similar measurement of dielectric constant is made with a strong electric field applied across the material such that the molecules are re-oriented unless the device is so cold that the molecular change cannot occur and the device is inoperative as a display. By comparing the dielectric constants, it is determined whether the device is at a suitable operating temperature and a heater for the device is controlled accordingly.

Abstract: A pair of mandrels crossing at a right angle are moved into the center of an O-ring and then spread apart to stretch the O-ring around the mandrels to secure it and to form it into a twisted path. The mandrels are rotated to drive the O-ring through the twisted path so that the angular orientation of any given cross section of the O-ring changes as it advances around the path. An optical measurement apparatus senses cross section diameter of the O-ring at several locations. A support for one of the mandrels accommodates a load cell to measure the force developed by stretching the O-ring to provide a measure of O-ring elasticity.

Abstract: A twisted nematic liquid crystal device contains a liquid crystal material having dielectric anisotropy .DELTA..epsilon. which is positive for certain values of temperature and frequency of an electrical signal applied across the material and negative for other values of these parameters. The device includes a heater and a test area (separate from the display area of the device) at which transmittance of light is monitored by a heater control circuit. A test frequency chosen to give .DELTA..epsilon..apprxeq.0 at the minimum desired operation temperature of the device is applied across the test area and the light transmittance is monitored to assure that the temperature is high enough. When the temperature is too low, the heater element is automatically energized to increase the temperature of the liquid crystal device.

Abstract: A float operated fuel level sender for an automotive vehicle fuel tank includes a molded plastic case secured to a conductive plate. A potentiometer assembly (electrically connected to a fuel gauge) includes a resistor secured within the plastic case and a wiper element movable with the float arm along the length of the resistor. The wiper element is electrically and mechanically connected to the float arm which in turn is connected through a contact element to the conductive plate to provide an electrical ground return. The plastic case has an integral resilient finger formed therein which is biased against the end of the float arm to urge the contact member against the conductive plate thereby assuring a good ground connection.

Abstract: Coherent optical correlation is applied to an article having circular features as well as noncircular features. A spatial filter is constructed for a typical part with the noncircular features masked out. The filter is placed in the transform plane of the optical correlation system so that the system will produce correlation signals indicating the presence, the coordinate position and angular orientation of the part within the field of view of the system.