Abstract: An apparatus for data transfer with a magnetic disk having a metal made hub attached centrally thereto, with the hub having a first opening defined centrally therein and a second opening defined eccentrically therein. The apparatus includes a turntable which is mounted on a drive spindle and on which the magnetic disk is to be placed with the drive spindle engaged in the first opening in the disk hub. Arranged eccentrically on the turntable, a drive pin is engageable in the second opening in the disk hub for transmitting the rotation of the turntable to the magnetic disk. The drive pin is mounted on a leaf spring for retraction into the turntable when the magnetic disk is loaded thereon with its second opening out of register with the drive pin.

Abstract: In a stepping motor of the type having one or more sets of four phase windings on respective stator poles, with the four phase windings being excited sequentially to cause the rotation of a rotor having magnetic poles, a drive method and system are disclosed for stopping the rotor in exact angular positions required. Since the stator can less magnetically control the rotor when the latter is positioned with its magnetic poles in axact alignment with the stator poles, the stator windings are sequentially excited in such a manner that upon termination of the sequential excitation, the rotor comes to a stop in a position angularly displaced to a predetermined degree in a predetermined direction from a position of exact alignment with the stator poles. Basically, for stopping the rotor in such angular positions, at least two of the four phase windings are excited at a time with currents of predetermined different magnitudes.

Abstract: A drive method and system are disclosed for a stepping motor typically having several sets of four phase windings on respective stator poles of annular arrangement, and a rotor having several alternating N and S poles at constant circumferential spacings. Normally, the windings are sequentially excited as by a single or two phase drive mode to cause the rotor to rotate by increments. For stopping the rotor in a required angular position, any one or two of the four phase windings are excited in a normal direction to polarize the associated stator pole or poles into one polarity to attract one of the opposite poles of the rotor. Further, the other phase windings on both sides of the noted one or two windings are excited in the reverse direction, as by the discharge of capacitors, with the consequent polarization of the associated stator poles into the opposite polarity.

Abstract: An apparatus for data transfer with a magnetic disk having a diameter of, say, 86 millimeters, having a pair of transducer heads for data transfer engagement with the opposite surfaces of the disk mounted on a turntable driven directly by a disk drive motor. In order to hold the magnetic disk exactly level on the turntable for proper data transfer contact with the transducer heads, a leveling mechanism is provided whereby at least the turntable is made adjustably movable in its axial direction with respect to the frame of the apparatus, as by the manual turn of an adjusting screw or screws. In one embodiment, the turntable is movable with a drive spindle on which it is mounted coaxially and which forms an output shaft of the disk drive motor. In another embodiment, the turntable travels with the complete disk drive motor.

Abstract: A data transfer apparatus for use with a magnetic disk having a hub of magnetic material attached centrally thereto, with the hub having a central hole and an eccentric slot defined therein. A drive mechanism for imparting rotation to the magnetic disk includes a turntable having a spindle projecting therefrom for centering engagement in the central hole in the hub of the magnetic disk placed thereon, and a drive pin mounted eccentrically on the turntable for driving engagement in the eccentric slot in the disk hub. Also mounted on the turntable is a permanent magnet of approximately annular shape for attracting the disk hub. The magnet has both north and south poles on its surface opposite the hub of the magnetic disk on the turntable, so that a closed magnetic circuit is formed for the reduction of leakage flux that might adversely affect the data transfer of the apparatus with the magnetic disk.