Abstract: A test set for measuring magnetic properties of magnetic amplifier cores wherein a repetitive constant current sinusoidal drive signal for producing a magnetic field in the core is repeated at a low duty cycle rate of not more than one full sine wave in one hundred sine waves. The test set includes a test fixture wherein portions of the primary and secondary windings are connected in a cover and table and terminate in mating contacts rigidly extending therefrom, such that when the cover is moved from the table, the windings are separated at their mating contacts so that a test core can be inserted within the windings.

Abstract: A proximity detection system for non-contact displacement and proximity measurement of static or dynamic metallic or conductive surfaces is provided wherein the measurement is obtained by monitoring the change in impedance of a flat, generally spiral-wound, printed circuit coil which is excited by a constant current, constant frequency source. The change in impedance, which is detected as a corresponding change in voltage across the coil, is related to the eddy current losses in the distant conductive material target. The arrangement provides for considerable linear displacement range with increased accuracies, stability, and sensitivity over the entire range.

Abstract: An inspection apparatus for inspecting and detecting flaws in serially fed substantially cylindrical objects. The inspection apparatus includes a notch-shaped inspection station formed by a pair of drive wheels mounted on a first shaft and a pair of discharge wheels fixedly mounted on a second shaft, parallel to the first shaft. A hook having a convex back surface is connected to and protrudes beyond the circumference of each discharge wheel. An L-shaped bracket whose body includes a sending surface and whose leg includes an infeed cradle, is mounted above the drive wheels and pivots in synchronism with the rotation of the discharge wheels. A first object in the infeed cradle is positively sent by the bracket sending surface toward the inspection station as the hook convex back surfaces are rotating up through the inspection station.

Abstract: Apparatus for non-destructive testing of metal blanks, in particular steel slabs, flat steel, billets or blooms, for defects such as cracks, seams, cavities, bubbles or the like disposed at or near the surface comprising one or more inspecting heads movable relatively to the surface of the test objects and provided with inspecting means for detecting such defects, said inspecting heads being held by means of pressure and tension members which are carried by a common support arm and transmit the pressure and tension forces substantially separately from each other so as to be individually movable up and down perpendicularly to the slab surface and constrained to move in the travelling direction in engagement with the slab surface.

Abstract: An interchangeable end piece for fastening to the front surfaces of a soft-iron magnetic yoke of a measuring probe which measuring probe is used for measuring the thickness of thin non-ferromagnetic layers on a ferromagnetic base comprising a pin element having a headplate, a contact piece welded to the headplate which contact piece is made from a mass-produced, high-precision steel element having a contact surface with a single radius of curvature, the radial angle of the contact surface, measured from the center of the underside of the contact piece, is much smaller than 90.degree., the surface of the contact piece outside the radial angle range is depressed, the maximum surface described by the radial angle is much smaller than the cross-sectional area of the pin element up to the rim of the underside of the contact piece.

Abstract: A method and apparatus for providing a digital display representing the magnetostrictive characteristics of a test specimen is disclosed. The apparatus is useful in combination with a test fixture of the type having means for inducing a periodic and alternating induction in a test specimen and including at least one displacement sensitive transducer mounted in association with the test specimen for generating a magnetostriction signal reflecting the magnetostrictive deformation of the test specimen in response to the induction. The apparatus includes a timing circuit associated with the means for inducing the induction in the test specimen, the timing circuit being adapted for producing a series of timing signals identifying the occurrences of zero and maximum induction in the specimen.

Abstract: A magnetostrictive mechanical, variable frequency stress transducer is disclosed in which the frequency of the output signal is proportional to the applied stress. This device consists of a magnetic stress actuating member, to which the stress is applied, and a transistor-magnetic oscillator constructed so the stress sensitive magnetic characteristic of the stress actuating member is the principal frequency determining element of the oscillator.

Abstract: Magnetoresistive displacement transducer arrangement for toothed magnetic members in which each transducer is formed by a pair of interconnected sections spaced from each other by the width of a tooth to provide greater change and improved symmetry in the output signal at the tooth edges. Multiple transducers can be positioned interdigitally for compact packaging for vernier type detection of motion. Transducer embodiments for both linear and rotary motion are disclosed.

Abstract: Apparatus to examine a magnetic storage layer expected to contain a magnetic watermark includes means to magnetize the layer with a unidirectional field of a selected strength without saturating it and means to detect any distinct region of magnetic remanence. The apparatus may further include means to record the resultant remanence levels (or their ratio) for such a region and another part of the layer, means to magnetize the layer with a unidirectional field of a different selected strength, means to detect any then-existing such distinct region or regions, means to measure the remanence levels (or their ratio) for the then-existing such region and another part of the layer, and means to compare the measured and recorded levels (or their ratios) and indicate from the result of the comparison whether or not this represents a layer having a magnetic watermark of regions of distinctly aligned anisotropic magnetic particles.

Abstract: A magnetoresistive detection device for determining the presence or absence of a single-wall magnetic domain at a position in a thin layer of magnetic material in which stable single-wall magnetic domains can be moved, comprising a sensing element of magnetoresistive material which is provided with respect to the layer of magnetic material in such manner that the resistance thereof varies when a single-wall magnetic domain is present at the said position. The device comprises means to produce an alternating magnetic field so as to modulate the size of a single-wall magnetic domain present at the said position, and comprises a filter which passes only interference-free terms of the signal detected by the sensing element.

Abstract: A method of eliminating the effect of non-equipotentiality voltage on the Hall voltage based on the non-reciprocal behavior of a Hall generator whereby a Hall generator or cascade-connected Hall generators are energized with current alternately through one of two pairs of opposite electrodes, while the output signal is obtained from across the other pair of electrodes or a Hall generator or cascade-connected Hall generators are energized through each pair of opposite electrodes with currents equal in magnitude but differing in frequency, while the output signal is obtained from the same pair of electrodes, and then the true value of the voltage of the Hall generator or of the cascade-connected Hall generators is assessed from the arithmetic mean of the magnitudes of the converted signals.

Abstract: The invention relates to a system and method of testing small cylindrical parts wherein a part is journalled for free rotation about a substantially stationary axis with one side of the part being frictionally engaged with a magnetic tape moved longitudinally to rotate the part and to transfer a magnetic flux pattern at the surface of the part to the tape. Important features relate to the provision of engagement means for obtaining non-skid intimate contact between the tape and the part, to the application of a biasing field to the tape at the area of interengagement between the tape and the part and to the manner of supporting the part.

Abstract: An apparatus designed for measuring the magnetic flux distribution along magnetizable members, specifically, magnetically latching reed capsules, which apparatus is characterized by an elongate thrust arm, in tubular form, which is mounted to reciprocate along a path provided by spaced support members and which has a drive connection with a motor at one end thereof so that a tubular portion at the opposite end which carries search coils with leads enabling connection to an oscilloscope for recording flux intensity, will telescope the magnetic members which are supported in a holder at that end of the path and which extend into a tubular portion of a bobbin member mounted at that end of the path, within which the search coil is reciprocated and on which an energizing coil may be wound with connection to a current source.

Abstract: Apparatus for non-contact measurement of the distance between a detecting coil and a metallic body mounted in confronting relation thereto comprising a differential amplifier to one terminal of which is connected a reference oscillator and to the other terminal of which is connected a feedback circuit. The feedback circuit incorporates the detecting coil and the amplified differential output signal between the AC signals applied to the differential amplifier and the signal supplied to the differential amplifier resulting from the impedance of the detecting coil corresponding to the distance between the detecting coil and the metallic body are thus a measure of the distance.

Abstract: Apparatus for gauging location of a movable element in relation to an end of an elongated impulse wave energy propagative member employing a sensing transducer adjacent one end of the member to sense first the direct impulse and thereafter the indirect impulse that is reflected from the opposite end. Processing of the sensing transducer responses and sequentially programmed digital measurement of time intervals associated with the duration and time relationship of such responses according to logic equations affords the desired location indication with automatic compensation for ambiently caused variations in shock wave propagation velocity in the member on repeating cycles of operation and with measurement accuracy independent of undue precision requirements in location of the sensing transducer in relation to the adjacent end of the member.

Abstract: A device is provided for the determination of the components of a terrestrial magnetic field as well as transitory variations therein. Two variometers including permanent magnets, mounted so that there is a constant angle between them, detect the magnetic field. A calculation system is provided for the determination of the direction and magnitude of each compensating field generated by the two variometers. Proper operation of the calculation system is assured without regard to the orientation of the device with respect to the magnetic north pole. Accordingly, the device may be used in any orientation and is thus suitable for use in such locations as the ocean floor. According to a preferred embodiment of the invention, the two variometers are mounted at right angles to each other.

Abstract: A contactless inductance interface pickup, having within an external housing an auxiliary housing installed, and formed as a pot, with at least the bottom thereof being constructed from a non-magnetic material, and a clearance between the external housing and the auxiliary housing wherethrough a cooling agent flows around the pickup. Inside the auxiliary housing, in immediate proximity to the bottom thereof, a magnetic circuit is disposed with at least one measuring winding and at least one energized winding.

Abstract: Superconducting quantum interference devices (SQUID's) are described including two superconductor pathways connected together by a narrow bridge of a granular superconductor material having a high normal state electrical resistivity of about 10.sup..sup.-4 to 10.sup..sup.-2 ohm-cm. The latter material is preferably a granular superconductor including superconductor grains having a low normal state electrical resistivity embedded in a matrix of a material having a high normal state electrical resistivity.Also described is the use of such devices in linear applications, such as in a magnetometers, and digital applications, such as switches, flip-flops, and memory cells.

Abstract: An eddy current flaw detection apparatus which is particularly adapted for inspecting articles at elevated temperatures. A plurality of detectors are supported about at least a portion of a workpiece path of travel to detect and locate flaws in workpieces. A non-magnetic, metallic shield is between the detectors and the workpiece path. A cooling medium is applied to the heat shield to protect the detectors from the heat of a hot workpiece. The cooling medium is also used to purge foreign matter from the assembly.In one embodiment an exciter and detector assembly is disclosed which is constructed as an integral unit encapsulated within moisture-impervious material. In this embodiment, the assembly is movable relative to the workpiece path.In another embodiment, the detectors and the exciter surround the workpiece path.Metallic powder is sprayed on a hot workpiece to mark the location of detected flaws. The heat of the article fuses the marking metal powder in place on the hot workpiece.

Abstract: A new and improved wire line operated well tool for sensing metal in wells and the like, wherein a pair of coils spaced along the tool axis are moved through the well and respond unequally to ferrous material in the well. The coils are activated on alternate cycles of AC energy supplied from the surface, and the AC responses are transmitted back to the surface to indicate the location of the ferrous material. Means are provided to block any DC pulses, as could be caused by galvanic action, from disrupting the meaningful data.