Abstract: A single toroidal core is wound with excitation/detection windings for reciprocal-integral eddy current driving-detection means, the pick-up coil being wound around the circumference of the toroid core. The utilized fields being orthogonal for an inherent null. The preferred excitation is ramping sine-cosine currents generating a variable angular velocity driving dipole. A rotating field torus core having an excited poloidal winding for generating concentric n-s s-n diameter-wise dipoles on the plane of the torus for shifting the hemispherical sensing field eccentric in an orbital motion.

Abstract: The passive torsional flux characteristics of polar sensors as related to the effective flux length coupling the pick-up coil are elucidated. A sine-cosine excited toroidal driving core comprising stacked magnetic materials having different permeabilities for enhanced helical induction coupling to the pick-up core. Also an active torsional flux means utilizing stacked driving toroids concentrically coupled to the polar sensor pick-up core. Also, integral sensor/driver embodiment utilizing at least two stacked toroids.

Abstract: A combination of three factors for increasing the spatial resolution of a polar coordinates sensor. (1) a coefficient of coupling factor including a gap in the magnetic circuit path between the driving core and the pick-up core. (2) a tuned "tank-circuit" factor including a capacitor connected in shunt with the pick-up coil. (3) a driving frequency spectrum factor for modulating the frequency of the sine-cosine excitation to the driving core.

Abstract: A method of increasing the spatial resolution of polar coordinates sensor devices by phase-amplitude modulating the sine-cosine excitation signals to the hollow toroid driving core. A rotating elliptical sensing pattern is generated by digital synthesis means. Values of the elliptical sensing pattern and its complete revolution are stored in digital "look-up" tables and sequentially read at a high rate into two digital-to-analog converters to produce two "staircase" approximations of the sine-cosine waveforms. The ellipse generation has a first angular frequency and the ellipse precession has a second sub-multiple frequency.

Abstract: An elongated hollow toroid driving core having a pick-up core formed as an integral part. A cross shaped driving core having two orthogonal sine-cosine excited flux circuits, a polar sensor is mounted where the cross arms intersect, the axis of the polar sensor being perpendicular to the driving core surface, thus disposing the winding turns of the pick-up coil coplanar to the driving flux lines. A third embodiment of a driving core device includes a hollow toroid and cross shaped driving core combination providing dual interacting rotating fields generating a sensing pattern having additive or subtractive dipoles that may be steerable.

Abstract: A polar coordinates sensing array, having a plurality of pick-up poles arranged in a flux balanced hexagonal configuration within a cylindrical outer pole, array driven by a rotating magnetic field within a hollow toroid core excited by sine-cosine excitation, each pole being wound with a pick-up coil for generating a plurality of polar coordinates signals representive of workpiece geometry.

Abstract: A joystick transducer utilizing a rotating magnetic field within a hollow toroid core, this rotating field drives a polar sensor element to which a 360 degree variable flux coupling element is operated by a joysyick to generate an output signal the phase angle of which corresponds to the azimuth direction of joystick tilt and the amplitude of this same signal corresponds to the magnitude of joystick tilt. A plurality of independent joysticks are also provide on one hollow driving core.

Abstract: A polar coordinates sensor probe, having a plurality of circularly arranged pick-up poles driven by a rotating magnetic field originating in a hollow toroid core, for detecting the reflected rotating eddy current pattern in material (both ferrous and non-ferrous) surrounding fastener holes, wherein the flaw is detected by means of mutual phase-amplitude comparison and adjacent pick-up pole signal phase deviation. The second embodiment having an isolated multi-pole pick-up core, picking up a rotating figure 8 eddy current pattern. Also embodiments utilizing Hall effect and magnetoresistive devices with the rotating magnetic field for flaw detection.

Abstract: Apparatus for measuring the sidewall thickness of cylindrical articles during in-process ram and die drawing, inclined axis multiple polar sensors induce eddy currents by means of the angular motion of a rotating magnetic field, the signal phase angle representing sidewall thickness, also ram and die centering signals generated. Inclined axis polar sensors also measure both cylindrical and flat article hardness by phase shift.

Abstract: An apparatus for detecting surface flaws in cylindrical articles by means of asymmetric magnetic detection, utilizing a rotating magnetic field, said articles having central longitudinal axes, apparatus having a guide assembly for guiding the cylindrical articles along a displacement path having a central longitudinal axis extending coaxially of the central longitudinal axes of the articles and a pair of multiple polar sensor assemblies positioned in annular relationship with the displacement path for producing a plurality of phase/amplitude modulated signals representative of the surface geometry of the inspected cylindrical article, also disclosed are two embodiments of cylindrical container flange imperfection detector apparatus utilizing multiple polar sensor assemblies.

Abstract: A rotary sensing device for indicating the angular displacement of a shaft is disclosed which comprises a magnetic core member formed of ferromagnetic material, a first winding wound within the core member for producing a first magnetic field in a closed path throughout the core, a second winding wound around the core member for producing a second magnetic field in a closed path throughout the core, the first and second magnetic fields being orthogonal to each other, and a pick-up coil assembly associated with the magnetic core member, the magnetic fields, and the shaft for sensing angular displacement of the shaft. A proximity sensor for sensing the passage of an object and the direction of passage of the object is also disclosed.