Abstract: An infrared detector capable of obtaining coincident fields of view of infrared radiation of different wavelengths is provided. The detector comprises a sandwich-type construction including PbSe and PbS photoconductive film layers.

Abstract: The present invention relates to a shutter mechanism including a shutter adapted to rotate 45.degree. from closed to open positions and which is self locking in both positions.

Abstract: An apparatus for the detection of impact frequencies in moving railway train bearings which are characteristic of bearing defects. The apparatus transduces acoustic vibrations of the bearings into an electrical signal and extracts an envelope modulated carrier frequency component from the electric signal. The envelope is extracted from the carrier frequency component and is analyzed by a bandpass filter. The bandpass filter includes a switch capacitor filter controlled by a master clock which, in turn, is controlled by train speed and/or direction sensors positioned along the track on which the train travels.

Abstract: This invention relates to apparatus for the detection of accustic impact frequencies, characteristic of bearing assembly failure during operation, which modulate an acoustic carrier frequency band. This apparatus allows for on-site or field application with high-level of ambient noise such as are present in railroad yards. This apparatus allows for early detection of such failures, so that a repair may be made before damaging heat build-up or catastrophic bearing failure occurs. Additionally, with sufficient early warning in railroad applications, a train may continue running to a railyard for convenient shop repair rather than expensive field repair.

Abstract: A hot box detector system is provided wherein heat signals from bearings within a housing are analyzed to determine if the scanned surface of the housing is an inner sidewall surface or an outer sidewall surface. The signals are normalized to account for differences in the heat dissipating characteristics of the inner and outer sidewalls and air stream cooling resulting from the trains movement.

Abstract: An improved heat sensing tip for a temperature sensing device is provided. The tip comprises an elongated shell of heat conductive material. A temperature probe is positioned for movement within the shell toward and away from an opening in the shell. A cap of heat conductive material is positioned at the front of the probe. A spring urges the cap in contact with the shell for heat conductivity between the two when the device is not in operation. When the device is in operation, the spring bias is overcome thereby providing an insulating air gap between the shell and the tip.

Abstract: A speed independent system is used for obtaining a preselected number of samples from an object moving along a fixed path, such as a railroad train passing through a sensing zone along the section of track. The sensing zone is defined by a pair of wheel sensors. Upstream of the sensing zone a third sensor is positioned. The distance between the third sensor and the closer of the pair of sensors comprises a reference distance which is the length of the sensing zone multiplied by a known multiple. The time for the train to pass through the reference distance is obtained and then divided by a divisor comprising the product of the known multiple and the desired number of samples to obtain a single interval. During the time the train passes through the sensing zone consecutive intervals are counted off to obtain the desired number of samples.

Abstract: A method is provided for determining whether an output signal from a magnetic railway wheel detector is produced by the actual passage of a wheel over the transducer. The output signal is compared with an amplitude threshold value and the time period between the zero crossing point and the time at which the signal attains amplitude threshold is compared with a time threshold level. The thresholds are set as a function of the speed of the train. Unless the thresholds are exceeded the output signal is disregarded.

Abstract: A system to permit the visual observation of objects moving along a fixed path. The object is viewed through a television camera which images the object through an optic axis bending element. The bending element is angularly rotated in a sawtooth manner with the slope of the sawtooth determined by the speed at which the object moves along the path so as to track the object to immobilize the scene viewed by the mirror.

Abstract: A railroad car hot box detector system is provided which includes a variable circuit means for processing the heat signal generated by an infra-red detector viewing a sensing zone along a section of track. The system includes a conditioning circuit which determines one or more conditions of the train (such as the wheel speed or temperature of the car bottom) and uses that information to vary the processing circuit to enable the heat signal to be processed optimally for the detected condition.

Abstract: An improved method and circuit is provided for processing waveforms from a railway car heat signal to eliminate spurious signals and to differentiate between roller bearings and friction bearings in a railroad hot box detector system. The waveforms generated by passing bearings are discretely sampled and spurious signals are eliminated by considering only those signals that fall within the crossing points of a threshold value. Discrimination between roller bearings and friction bearings is obtained by determining the ratio of the sum of the discrete values of the amplitude of the waveform within a first set of samples between the crossing points to the sum of the discrete values of the amplitude of the waveform within a second set of samples between the crossing points.

Abstract: A quasi-doppler direction finder is provided wherein the alternate dipole elements are divided into two groups. Each of the groups is connected to an associated RF attenuator which is driven by a control signal 180.degree. out-of-phase from that for the other group. Commutation between dipoles occurs so that there is a 50% overlap of "on" time between adjacent dipoles. Switching for each dipole occurs when its associated modulating function passes through zero.

Abstract: A device to simulate the rolling of a hypothetical wheel along a path is provided. The device includes a wheel sector mounted to one end of a rotor. A drive is provided for rotating the rotor in one direction and the sector in the opposite direction so that the sector remains substantially tangent to a line segment. The wheel sector is driven by a pulley the diameter of which is one-half that of a drive pulley rotated with the rotor.

Abstract: A system is provided for determining whether a railway car passing a sensing station is a freight car. The system utilizes wheel trips along the track at the sensing station to determine the spacing between axles of the car. If the spacing between axles is determined to fall between slightly more than 4' - 5" to slightly less than 6' - 1" the car is presumed to be a freight car.

Abstract: A jogging switch mechanism is provided for a potentiometer which permits the potentiometer shaft to be rotated either clockwise or counterclockwise and then, upon release, to return automatically to a very accurately centered neutral position. The neutral position may be an "off" position by positioning micro switches in the path of travel of the switch mechanism.

Abstract: An improved circuit is provided for differentiating between roller bearings and friction bearings in a railroad hot box detector system. The improved circuit integrates the waveform generated by a bearing scanner and compares that to the integral of a pre-selected portion of the waveform. By this method of comparison, irregularities in the system due to noise are obviated.

Abstract: A self-cleaning label is provided for use in an automatic object identification system. The label comprises a backing member having a plurality of fins attached to it. A strip of reflective material is affixed to the front surface of each fin for "reading" by the components of the system. The fins are aerodynamically designed so that the flow of air past the label carrying surface serves to clean the surface and prevent the settling of dirt thereon.

Abstract: A circuit for producing an output pulse of predetermined amplitude and a width equal to the mid amplitude width of an input pulse from an electro-optical label reading system is provided. The present circuit comprises delay line means having a first output terminal and a second output terminal with the signal at the second output terminal being delayed twice the time of the delay at the first terminal. The first output terminal of the delay line is connected to an amplifier operative to double the amplitude of the signal applied thereto. The output of the amplifier is connected to one input of each of first and second comparators with the other input to the comparators respectively connected to the input signal source and the second terminal of the delay line. The output of the comparators is connected to the input to an AND gate with the output from the AND gate providing the desired pulse width information.

Abstract: A system is provided for time multiplexing a plurality of optical scanners. The system includes at least two electro-optical detection systems, each including means for receiving an image of an object and producing an electrical signal output in response to the sensing of an image, mirror means movable to scan a first location and reflect an image of any object at the first location to the first detection system and to scan a second location to reflect an image of any object at the second location to the second detection system and means for moving the mirror to continuously scan the first and second locations. The system further includes means for processing the electrical signal outputs of the detection system and switch means for alternately connecting the outputs of the first and second detection system to the processing means.

Abstract: A system is provided for determining the passage of a railroad car wheel along a section of track and the direction of movement of the wheel. The system includes a first wheel sensor mounted adjacent the track and adapted to generate a signal upon the passage of a wheel past the first sensor and while the wheel remains within a length of track associated with the first sensor. The system further includes a second wheel sensor closely spaced along the track from the first sensor and adapted to generate a second signal on the passage of the wheel past the second sensor and while the wheel remains within a length of track associated with the second sensor. The first and second sensors are sufficiently closely spaced to each other so as to provide an overlap between the first and second signals as a wheel passes. Logic means are connected to the outputs of the first and second sensors for determining the direction of travel of the wheel by the sequence of output signals from the sensors.