Abstract: A demagnetization apparatus for use with magnetically based electronic article surveillance systems having a dual status anti-theft marker containing at least one demagnetizable control element which when demagnetized allows the marker to be detected by the system when the marker is present in an interrogation zone. The apparatus includes an elongated magnetic section contained within a housing which exhibits a succession of fields of alternate polarity and at least a portion of which exhibits exponentially decreasing intensities at the working surface of the housing along that portion of the section. The section and a cover plate are orientated such that the external fields near the working surface are sufficient in intensities to demagnetize the demagnetizable element of the marker positioned proximate thereto while being rapidly attenuated a short distance from the section.

Abstract: An apparatus for sensing the relative rotational position between a stator (28) and a rotor (32) in a variable reluctance motor (26) includes a transmitting ring (40) mounted to the rotor (32) and having a transmitting coil (46) mounted thereon. A receiving ring (42) is mounted to stator (46) and has a receiving coil (56) mounted thereon. The receiving coil includes three conductor patterns (56a, 56b, 56c) having the same shape, each of said conductor patterns being electrically insulated from each other, and each conductor pattern being offset from adjacent conductor patterns by 120 electrical degrees. A drive signal is coupled to the transmitting coil. The apparatus further includes a controller (76) for monitoring the outputs from the receiving coil patterns and for determining the relative rotation between the rotor and the stator from the monitored outputs. The receiving coil patterns are each arranged in a circumferentially varying square wave pattern.

Abstract: A torque sensor for use in a power assist steering system for sensing the applied steering torque between an input shaft and an output shaft wherein said shafts are coaxially aligned with each other and rotatable relative to each other about a common axis. The sensor includes a non-planar rotary input transformer having a stationary primary winding and a rotary secondary winding, both mounted coaxially about a common axis. A transmitter is mounted to the input shaft for rotation therewith and carries, on one axially directed face, a coil set of series connected coils arranged in an annular array about the common axis. A receiver is axially spaced from the transmitter and is mounted on the output shaft for rotation therewith about the common axis. The receiver carries, on an opposing axially directed face, first and second sets of series connected coils each arranged in an annular array about the common axis and with the coil sets being electrically displaced by 90.degree..

Abstract: A DC motor utilizing flux focussing pole pieces and non-ferrous spacers to wedge the pole pieces and magnets into contact with the motor housing. Cooling is provided with heat pipes mounted in the spacers or pole pieces and/or the motor armature.

Abstract: A Hall effect shaft angle position encoder is constructed using a plurality of magnetic elements independent of any magnetic rotor of the electrical device which may be a brushless motor or brushless tachometer. The plurality of magnetic elements has serially alternating polarities of magnetic north and south with at least one Hall effect sensor mounted in spaced and confronting relation with the magnetic elements for sensing the alternating polarities and producing output signals representative of the magnetic polarities where the signals include a ramp voltage passing through zero value. The magnetic elements are secured to the rotor outside the normal rotor elements of the device.