Abstract: A proximity sensor using the magnetic field of a single length of sensor wire. The sensor has a supply circuit for generating a magnetic field around the single sensor wire. The sensor also has a detection circuit for detecting when electrically conductive material intercepts the magnetic lines of flux of the magnetic field surrounding the single sensor wire. In a preferred embodiment the sensor wire is substantially straight and/or the detection circuit detects metal within a distance from the sensor wire approximately two or three times the main dimension of the cross section of the sensor wire. A plurality of sensor wires can be used and a passive actuator or scale can be used to intercept and alter the magnetic field surrounding the sensor wire. The scale can be formed of electrical short circuits aligned at constant steps. The sensor then detects the presence or absence or a short circuit in the magnetic field.

Abstract: An apparatus for rotating a spherical object, which includes suspension means for supporting a spherical object in a fixed position relative to its center. The suspension means holds the sphere by simultaneously contacting its surface with contacting elements at at least four points spatially independent of each other on the surface. Each of the contact elements is of regular shapes, such as, spheres, cylinders, cones or other shapes having symmetry about an axis of rotation. At least one of the contact elements is rotationally driven by a rotating drive means. The rotating drive means is rotated at a fixed or time-varying speed to impart controlled movement to the sphere about an axis through its center. The speeds or time-varying functions thereof cause the resultant controlled rotational motion of the sphere by manipulating an axis of rotation through its center.

Abstract: Methods of operation of an apparatus having at least two pairs of voltage measurement electrodes vertically disposed in a cased well to measure the resistivity of adjacent geological formations from inside the cased well. During stationary measurements with the apparatus at a fixed vertical depth within the cased well, the invention herein discloses methods of operation which include a measurement step and subsequent first and second compensation steps respectively resulting in improved accuracy of measurement. First and second order errors of measurement are identified, and the measurement step and two compensation steps provide methods to substantially eliminate their influence on the results. A multiple frequency apparatus adapted to movement within the well is described which simultaneously provide the measurement and two compensation steps.

Abstract: A centrifuge rotor overspeed protection system which can operate with rotors of at least two speed ranges. A set of coding elements are provided on the rotors coded to represent the actual maximum safe speed rating of the rotor. An additional set of coding elements coded to correspond to the maximum speed in the lower speed range are also provided such that the rotor can be operated at the maximum speed possible in a prior art centrifuge designed for operation in the lower speed range. The detection circuit for the coding elements automatically adjusts the detection threshold depending on the average values of the sensor output peaks corresponding to the codes.

Abstract: Since a superconducting quantum interference device (SQUID) using a high temperature superconductor operates at the liquid nitrogen temperature 77 K, which is higher than the liquid helium temperature 4.2 K, it is necessary that the value of signal voltages is at a level, which is sufficiently higher than the thermal noise level. The superconducting inductance L should be decreased with increasing current flowing through Josephson junctions in the SQUID. The superconducting inductance can be reduced by various methods such as reduction in the size of the aperture of the superconducting inductance, parallel connection of superconducting inductances, utilization of a superconducting ground plane, etc., in order to realize a SQUID, which can be use in a wide application field at the liquid nitrogen temperature 77 K.

Abstract: A method and apparatus for determining the distance from a relief borehole to a target well utilizes measurements of an electric field at the target well. The electric field is produced by injecting current into the earth near the wellhead of the target well, this current producing a target current in conductive material in the target well. The electric field corresponding to the target current is measured by means of sensors in the relief borehole, and this field measurement, together with a measurement of the alternating magnetic field at the relief well due to the target current, permits determination of the distance to the target well from the relief borehole.

Abstract: The invention relates to an apparatus for implementing the automatic measurement of a spinning saw blade's lateral deformation or deflection otherwise known as "flutter." The apparatus comprises a mounting means for rotating the saw blade and a detector means for measuring the flutter of the saw blade and generating an electrical signal in response. A second means measures the spin of the rotating saw blade in order to provide a visual output signal indicating flutter as a function of rotational speed.

Abstract: A method and apparatus for determining electromagnetically the locations of electrically conductive bodies beneath the surface of the ground, wherein a primary electromagnetic field is generated with the aid of a loop through which a sinusoidal alternating current is passed. The loop is placed at or above the level of the ground beneath which the locations of conductive bodies shall be determined. There are currents generated in the conductive bodies which, in turn, generate a secondary electromagnetic field. The values of the amplitude and phase of the magnetic component of the thus formed total electromagnetic field are measured with the aid of coils mounted inside a probe which is lowered to different depths in a borehole. The values of the primary field phase are measured continuously by at least one reference coil which is placed outside the probe, either above or beneath the surface of the ground, within the propagation area of the primary field.

Abstract: An inductive displacement transducer is provided having a two-piece probe assembly capable of being displaced within the hollow interior portion of a coil. The probe assembly comprises a cylindrical rod disposed within a tube. The rod and the tube are each movable with respect to each other and with respect to the coil. The coil is uniformly wound and is connected electrically in parallel with a stable-frequency current-based oscillator which transmits an AC voltage oscillating signal corresponding to the inductance of the coil. A demodulating circuit, which is capable of converting the AC voltage oscillating signal to a DC voltage level, is connected in parallel with the oscillator. In the preferred embodiment, the coil is covered with a shield which is slit along its length. In operation, the two-piece probe assembly is displaced within a hollow portion of the coil such that a change in inductance results when the rod is displaced relative to the tube.

Abstract: A device for measuring the rotational speed of a shaft. A toothed wheel is connected to rotate with the shaft within a magnetic field. A birefringement optic fiber is connected to a light source, and passes through the magnetic field. A magnetorestrictive material is supported in contact with the optical fiber and produces stress on the optical fiber in response to magnetic flux variations. Light emerging from the optical fiber is analyzed with respect to its change in phase to determine the periodic variation in the magnetic field caused by the toothed wheel.

Abstract: A position sensor using a soft magnetic core and a permanent magnet for detecting linear or rotary movements of a part. In one embodiment, a differential transformer is provided with corresponding windings 3, 4 and 5, which are wound on a tubular carrier member 2. Provided inside the carrier member 2 are a saturatable core 6 with a V-shaped crosssection section and a control magnet 8 which slides on the inner surfaces. The core 6 is partially saturated on the contact surfaces, so that a virtual air gap is produced, so that the transformation ratio between the windings 3 and 4, 5 is controlled as a function of position. Other versions employ flat and/or meandering coil arrangements and, in two instances, rotational relative motion.

Abstract: An electromagnetic contactor assembly with a sensing circuit for determining contactor state based upon the reluctance of the contactor coil. The coil has an electromagnetic coil and a movable contact separated from the coil by a gap when the coil is not energized. Energizing the coil causes the movable contact to close the gap and contact the coil. The determination of the relationship between the reluctance in the coil when the gap is in an open and closed state allows contactor gap status to be measured by measuring the coil inductance. A sensing circuit is added to the drive circuit to measure changes in AC current during the pulse cycle which holds the contacts in this closed position. The sensing circuit measures the AC current and is able to signal contactor status based on that value.

Abstract: A piston-cylinder assembly is equipped with means for determining and validating the piston position of that assembly part of a robot. A piston 1 slides axially in a cylinder 2, and moves a permanent magnet 13. The resulting magnetic field is sensed by a Hall effect transistor. A member 12 is controlled by a program of analog signals coming from the sensor. When the run of piston 1 is stopped, the position of that piston is one of the positions that have been previously determined and memorized by control member 12.

Abstract: A magnetic sensor has first, second, third and fourth magneto-resistance effect elements disposed in a direction of a magnetizing pitch (1) of a magnetic recording medium serving to supply a magnetic signal, with first and second magneto-resistance effect elements disposed spacedly from each other at an interval corresponding to an electrical angle of .theta., the third and fourth magneto-resistance effect elements disposed spacedly from each other at an interval corresponding to an electrical angle of (360.degree.-.theta.), and the intervals between the center line of the first and second magneto-resistance effect elements and between the line of the third and fourth magneto-resistance effect elements being set to n.lambda..

Abstract: A piston cylinder device having a piston stroke measurement includes a cylinder tube (1) having an inner tube (2) made of a nonmagnetic material and an outer tube (3) formed on the outer peripheral surface of the inner tube and made of a fiber-reinforced resin material. A piston (76) fixed to a rod (75) is disposed slidably inside the cylinder tube. A stroke detector is composed of a position indicating magnet (80) disposed in the piston and an elongated sensor (81) disposed in the cylinder tube. The elongated sensor includes a thin elongated pipe (82) extending along the cylinder tube between both of its ends and holds at least one magnetostriction line (87) having a large magnetostriction coefficient, a driving coil (84) wound on at least one of the ends of the thin elongated pipe. A pulsed input current to the drive coil causes magnetostriction phenomenon on the magnetostriction line generating an ultrasonic wave.

Abstract: A detector having a housing (12), a mounting (3) which is able to adopt four orientations relative to the housing (12), and a detector head (4) which is able to adopt, relative to the mounting (3), two orientations in one of which a sensitive face (29) of the head is oriented laterally relative to the axis (Z) of the housing (12), while in the other orientation the sensitive face (29) is centered on the axis (Z). The mounting (3), which can be separated from the housing (12), can engage through either of two recessed faces (33, 34) of the head, by the sliding of slideways (56) of the mounting between a base (38) and protuberances (43) of the head. The position of association of the head relative to the mounting is defined by the abutment of faces (48) of the protuberances (43) against stop faces (57) of the mounting. A pivot (18) of the mounting is then fixed in an aperture (22 ) of the housing. This mounting is used in order to eliminate screw fixings.

Abstract: A magnetostrictive linear displacement detector includes a dual pole magnet assembly. The displacement detector includes a magnetostrictive wire, a return wire and a magnet disposed for displacement along the magnetostrictive wire. A torsional strain sensor at the head end generates an electrical indication of the torsional strain within the magnetostrictive wire induced by passage of an electrical excitation by the position of the magnet. The magnet of this invention is a cylindrical magnetic bipole. The magnet includes two toroidal magnet sections. The first toroidal magnet section has radially disposed magnetic poles with the South pole directed inwardly and the North pole directed outwardly. The second toroidal magnet is a similar radial magnet except that it has its North pole directly inwardly and its South pole directly outwardly. The magnet assembly has a length preferably no more than one half inch. This length should be short in relation to the total length of the measurement range.

Abstract: An inductance-type displacement sensor which can measure the displacement of a measured object of magnetic material without any contact with the object. A pair of series connected coils is provided adjacent to the object so that the inductance of the coils varies in response to a displacement of the object from a predetermined position. The inductance, the number of windings, the direction of the windings and the section of each of the cores are so set that the magnetic flux produced by one of the coils runs in a direction opposite to that of the magnetic flux produced by the other coil and the densities of the respective magnetic fluxes are identical with each other.

Abstract: Device capable of detecting the rotational speed of two elements in relative such as the support elements of a vehicle wheel, in particular the rings of the roller bearing for the support the vehicle wheel, characterized in that an initial deflector or ring integral with the rotating ring of the bearing carries twin magnetized rings with pairs of poles of opposite sign, between which a magnetic sensor carried by a second deflector or support integral with the fixed ring of the bearing being is operatively inserted, the magnetic sensor being located between the n polar expansions, the number of which conforms to the pairs of opposing poles of twin magnetized rings.

Abstract: A superlattice comprising alternating layers of undoped GaAs and silicon doped Al.sub.0.3 Ga.sub.0.7 As is used as a magnetoresistor for measuring magnet fields in excess of one Tesla. The magnetic field to be measured is passed vertically through the superlattice and current from a source of constant current is flowed vertically through the resulting superlattice and the voltage drop across the superlattice is measured to provide an indication of the strength of the magnetic field.