Micropolis Corporation

Ericson M Dunstan

William J Gervais

John E Scura

Bipin V Gami

Dennis Hogg

S Barry McClelland

Ming-Goei Sheu

A shock resistant hard disk drive system employs a plurality of magnetic disks for recording data, a plurality of magnetic heads for performing input/output operation on the magnetic disks, with at least one of the magnetic heads being used as a servo head, a head-positioning mechanism for controlling the movement of the magnetic heads, a servo control mechanism or servo loop for opposing shifts in the location of the servo head, detecting device for detecting and measuring certain accelerations applied to the system, and filtering device for filtering the output of said detecting device and for providing the signal to the head-positioning mechanism. The detecting device detects and measures the magnitude of internal or external accelerations or shocks applied to the system, and provides the necessary signals to counter such accelerations. The pre-existing phase locked loop includes a voltage controlled oscillator, with the voltage control signal applied to the oscillator indicating instantaneous rotational velocity resulting from accelerations applied to the system; and this control signal is modified and applied to servo loop for the head positioner, to hold the head positioner against shifting off track.

Shock resistant winchester disk drive

A 'floppy' disc digital magnetic storage apparatus or subsystem includes a number of interrelated features permitting greatly increased data storage and good access time, while using relatively inexpensive parts. The features contributing to the greatly increased storage capacity include arrangements for providing one hundred tracks per inch, and for holding tolerances so that the position of the magnetic head in the radial direction is maintained within the required value of plus or minus 1.7 thousandths of an inch. Features contributing to the high accuracy of magnetic head positioning, and the resultant high data capacity, include the following: (1) mounting the lead screw which positions the magnetic head with its inner end close to the center of the magnetic disc fixed in position, and with its outer end and the stepping motor secured to it mounted on a leaf spring pushing the motor and the outer end of the lead screw inward toward the inner end of the lead screw: (2) utilizing a simple sheet metal stepper motor having two sets of punched metal teeth which interfit with one another and which are exposed to a central permanently magnetized rotor having north and south poles successively located around its periphery; two coils are provided and each of these coils can be energized in opposite directions, with the four combinations resulting in progressive stepping of the permanent magnetic armature, with every fourth step having a more accurately defined angular position than the three intermediate steps; (3) by a special energization arrangement, the rotor is moved four steps at a time to shift the head from one track to the next, thereby using only the more accurately located angular positions, and reducing the adverse effects of friction on head positioning; (4) the electronic circuitry associated with driving the step motor is configured to offset any time penalty incurred by taking four steps to move one track; (5) the floppy disc is accurately positioned relative to the inner end of the lead screw by forcing the magnetic disc to an interference fit relationship with the driving spindle hub on which it is mounted, and (6) the lead screw is ground to mate with a conical pin secured to the movable head assembly.

High precision floppy disc memory system

A printed circuit motor is constructed with the printed circuit windings stationary, and therefore constituting the stator of the motor. The stator is mounted at the end of a heavy hollow supporting frame member. The rotor is mounted on the end of a shaft which is journaled within the hollow frame member, and the rotor extends outwardly in close proximity to the stator and around the outer periphery of the stator and back toward the hollow supporting member, with a permanent magnet assembly on one side of the printed circuit stator and the magnetic return path on the other side of it. The permanent magnet assembly and the magnetic return path are rigidly coupled so that no relative motion occurs between them. Electrical connections to the winding turns of the stator are brought out from the periphery of the stator close to its surface through an additional printed circuit board, and along the outer surface of the hollow frame member to pass the inner edge of the permanent magnet rotor. Timing for the energization of the coils of the printed circuit stator is controlled by three photosensors which are interrupted by the outer edge of the rotating return path of the rotor, which is provided with a peripheral interruptions to selectively block the light path to the photosensors. Six coils of the printed circuit stator are arranged in a Y-configuration and are selectively energized in accordance with the output from the photosensors.

Growing community of inventors

Hidden Hills, CA, United States of America

Ericson M Dunstan