Abstract: A sensor for measuring linear displacement has a core of magnetic material disposed for movement within a bobbin about which a coil of insulated, electrically conductive wire is wound. At least one Hall effect device is disposed about the coil. The sensor is contained with a magnetic housing. When the coil is excited by a DC power source, the direction of magnetic flux flowing through the Hall effect device is dependent upon the position of the core.

Abstract: A method for determining the resistivity of earth formations penetrated by a wellbore. Electrical current is imparted to the wellbore and the earth formations from a first electrode located on a mandrel disposed in the wellbore. The electrical current is returned at a second electrode on the mandrel at a spaced apart location from the first electrode. Voltage differences are measured between a first pair and a second pair of electrodes located on the mandrel between the first and the second electrodes. Circuits used to measure the voltage differences are adjusted until the measured voltage difference between the second pair is substantially the same as the measured voltage difference between the first pair. Then the electrical current is returned to an electrode at the earth's surface or other location distal from the first electrode, and measuring the voltage differences is repeated. A difference of the voltage differences is then calculated.

Abstract: A magnetoresistive film through which a sense current for detecting a resistance change due to a magnetic field to be detected flows in a longitudinal direction, and a lateral bias film which is magnetized in a fixed direction by a constant magnitude such that a lateral bias is applied to said magnetoresistive film in a lateral direction intersecting said longitudinal direction are arranged to be opposed to each other via a magnetic isolation film. By conducting said sense current by means of a pair of lead conductive films coupled electrically to both edges of said magnetoresistive film, a magnetization recorded on a magnetic record medium can be detected. Since the lateral bias is applied to the magnetoresistive film such that the lateral bias is not affected by the sense current and external magnetic fields, the magnetization of the magnetic record medium can be stably detected without being influenced by the sense current and external magnetic fields.

Abstract: A leadless motor rotation detector apparatus for determining the direction of shaft rotation of a motor providing a fluctuating magnetic field when rotating includes: at least two sensors separated a predetermined distance from one another. Each sensor senses the magnetic field and generates a corresponding sensor signal having an amplitude and phase associated with said sensed magnetic field. A processor is responsive to the sensor signals, and compares temporal aspects associated with the relative phase of each of the sensor signals to determine a leading or lagging signal. The leading or lagging signal is associated with a corresponding one of the at least two sensors and is indicative of the direction of motor rotation.

Abstract: A magnetic metal object retriever 10 with cover 20 having a magnet 140 for attracting metal objects 250. The magnet 140 is connected to an extendable handle 40 and covered by a cover 20. The magnetic metal object retriever 10 with cover 20 is used to gather metal objects 250 such as nails and screws, which are attracted by the magnetic pull from the magnet 140 and such metal objects 250 collect on the exterior of the cover 20. When the cover 20 is removed from the magnet 140, the metal objects 250 are easily removed and can be reused or disposed of.

Abstract: A method and apparatus for detection of rare earth metal oxide inclusions in non-magnetic metal. The method utilizes a D.C. magnetic search field coupled with a magnetic field sensor for detecting the response of a rare earth metal oxide casting fragment inclusion through the bending and amplification of the ambient magnetic field at the defect location.

Abstract: An A-base utility meter cover assembly is described. The meter cover assembly is fabricated of a thermoplastic injection molding material, such as polycarbonate, and includes a base cover covered by a terminal cover. In one embodiment, the base cover includes a terminal block cavity for receiving a utility meter terminal block, and two locking tabs and a snap portion which engage openings through the terminal cover when the base cover and terminal cover are in an assembled configuration. In the assembled configuration, a dam and deflectors on the terminal cover are aligned with ribs on the base to form a continuous barrier against water flow into the terminal block cavity. The configuration of the locking tabs and snap portion also protect against tampering with meter electronics by preventing removal of the terminal cover.

Abstract: A rotational sensing assembly including a ferromagnetic sensor wheel rotationally fixed to a shaft having a tooth pattern including a missing tooth. An inductive sensor is mounted adjacent the periphery of the sensor wheel and in communication with a processor. The sensor produces a generally sinusoidal signal in response to the wheel rotation, with voltage zero crossings that are time stamped by the processor. The geometry of the sensor wheel around the missing tooth location is altered to equalize the induced voltage in the sensor for fixed time intervals in order to maintain proper timing of the zero crossings in the sensor signal.

Abstract: This invention prevents the failure of detection for horizontal and oblique lift-offs in a probe for an eddy current flaw detection test. A plurality of probes are provided, and each probe includes four detection coils. Two adjacent eddy current flaw detecting probes commonly own (share) one of the four coils. The detection coils are connected to a bridge circuit for picking up a flaw signal. The detection coils are adjusted so that interlinkage magnetic fluxes generated inside the detection coils by the eddy current become equal. An excitation coil for inducing the eddy current in a test piece by AC driving can be disposed over the detection coils. The center of the excitation coil is positioned on the center axes of the detection coils. An oscillator for applying an AC current to this excitation coil is connected to the coil.

Abstract: A magnetic rotational position sensor comprises a loop pole piece, at least one magnet, and at least one magnetic flux sensitive transducer. The magnet is disposed within an air gap of the loop pole piece to establish a magnetic field through the air gap and to enclose magnetic flux within the loop pole piece. A control shaft is rotatable about a first axis and the loop pole piece and the magnet are adjoined to the control shaft to synchronously rotate the magnetic field about a second axis. A working air gap area is defined within the air gap area of the loop pole piece between a pole surface of the magnet and an inner surface of the loop pole piece. A magnetic flux sensitive transducer is disposed within the air gap to sense a magnitude of magnetic flux density.

Abstract: A process permits the determination of multi-dimensional distribution of magnetic fields. The process uses a magneto-resistive sensor as a physical measuring device. The measuring device is coupled with a method for algebraic reconstruction so that sectional images of the field distribution are calculated from individual measurements of the magneto-resistive effect using the algebraic reconstruction.

Abstract: A method of measuring magnetization direction of a MR device, includes a first step of obtaining both maximum electrical resistance values under positive and negative applied measurement magnetic fields onto the MR device biased by anti-ferromagnetic material, a second step of relatively rotating a basic axis of the MR device against a direction of the applied measurement magnetic field until both the maximum resistance values become comparatively the same, and a third step of obtaining a relative rotation angle between the basic axis of the MR device and the direction of the applied measurement magnetic field.

Abstract: A cross-coil type indicating instrument includes a bobbin having an upper center cylinder and a lower center cylinder, a cross-coil unit disposed around the bobbin, a shaft coaxially and rotatably supported by the upper and lower cylinder, a permanent magnet rotor, a dial, a pointer carried by said shaft, and a cup-shaped magnetic shield casing. The upper center cylinder has an upper bearing disposed to be generally flush with the upper surface of the cross coil unit, and the lower center cylinder has a lower bearing and extends through the magnetic shield casing so that the lower bearing is disposed at the back of the magnetic shield casing.

Abstract: The disclosure is directed to a method for identifying and classifying data surface defects on the disks of a rigid disk data storage device. By partitioning each surface into cells and sub-sampling every Nth track, the number and location of defects can be determined. The number of stored defects is then examined to determine whether clusters of contiguous cells exist wherein defect totals exceed a predetermined threshold number. This enables the location of clusters on multiple surfaces to be examined for axial alignment, radial alignment or random occurrence as an indication of the source of damage. To obtain further verification of the data surface condition, the location of a defect cluster can be scanned using a utility that evaluates each track within the defect cluster or area.

Abstract: A rotation angle sensor including a magnet rotatable about an axis, a first and second yokes arranged around said magnet and diametrically opposed to each other, and a Hall effect device disposed between the first and second yokes. The yokes include arcuately curved pole piece portions radially opposed to the magnet and overhang portions extending angularly inwardly from the pole piece portions across the axis of the magnet, respectively. The overhang portions have a generally sector shape and cooperate to define a gap therebetween within which the Hall effect device is disposed. Leakage flux reducing members circumferentially extend between the pole piece portions.

Abstract: A sensor for detecting the angular position of a rotary drive shaft is disclosed which includes a stator, a rotor connected to the stator by a ball joint and including a moving target, and a drive shaft connected to the rotor. The moving target passes through a detection system and produces a signal as a function of its position. Variations in the sensor output signal due to misalignment of the rotor and the drive shaft are minimized by locating the moving target close to the axis of rotation of the ball joint.

Abstract: A method of identifying a direction of rotation of a wheel using Hall probes which are disposed about the circumference of the wheel. In this case, a first, a second and a third Hall probe are disposed successively, so that the second Hall probe lies between the first and third Hall probes. From the output signals of the three Hall probes, two evaluation signals are obtained, through comparison of which the direction of rotation of the wheel is determined.

Abstract: A field sensor (1) comprising means for measuring a magnetic field and an electric field, wherein at least six capacitor plates (5, 6, 7, 15, 16, 17, 25, 26, 27, 35, 36, 37)are provided which are arranged in a cube and in that in the space thus formed the means for measuring the magnetic field is provided, which means is three-dimensionally aligned and for example consists of coils (2, 3, 4), Hall-effect sensors, magnetoresistors or the like.

Abstract: A magnet layer or antiferromagnetic thin film layer composed of a thin film serving as a bias magnetic field applying member is provided at both ends of a magnetic thin film having a magneto-impedance effect so that a bias magnetic field Hbi is applied to the magnetic thin film layer in parallel with the direction of application of an external magnetic field Hex to the magnetic thin film layer. As the magnetic thin film layer, a soft magnetic material having the composition ColTamHfn, FehRiOl, (Co1-vTv)xMyOzXw, T100-d-e-f-gXdMeZfQg or T100-p-q-f-gSipAlqMeZfQg is used.

Abstract: An inductive angle sensor includes: a stator element having an exciting coil with a periodic AC voltage applied thereto and several receiving coils; a rotor element that affects a strength of inductive coupling between the exciting coil and receiving coils as a function of its angular position relative to the stator element; and an evaluation circuit for determining an angular position of the rotor element relative to the stator element from voltage signals induced in the receiving coils. The rotor element forms at least one closed-loop lead that, at least over a partial area, forms a periodic repeating bend structure in a direction of a circumference of the rotor element. The inductive angle sensor provides a compact structure, a high resolution, and a particularly high degree of insensitivity to production and installation tolerances.