The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 14, 1995
Filed:
Jul. 13, 1994
Jeffrey S McAllister, Boise, ID (US);
Boyd N Shelton, Boise, ID (US);
Henricus M van Hout, PP Heeze, NL;
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A multiple pole, multiple phase, sensorless DC disk spindle motor in a disk drive is powered by direct current which is commutated among the motor phases from a DC power supply to start the motor and to rotate the disks at constant speed in a predetermined direction whenever the disk drive is in use. When the motor is prevented from rotating by the stiction bond of one or more transducers which have adhered to the disks, the direct current is reversibly commutated among the motor phases near the resonant frequency, a predetermined number of times, to produce substantially sinusoidal, bi-polar motor torques to achieve torque amplification to break the stiction bonds. Following the last of the predetermined number of reversible commutations of direct current, direct current commutation is initiated among the motor phases to rotate the motor and the disks in the desired direction at constant speed.