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:
Sep. 17, 1991
Filed:
Jul. 31, 1989
Jerome F Richgels, San Jose, CA (US);
John C Kuklewicz, Sunnyvale, CA (US);
Literal Corporation, Colorado Springs, CO (US);
Abstract
At the conclusion of a track seek operation, handoff to track following servo control is delayed for a short time period during which the drive microprocessor determines if the head has failed to stop at the target track by sensing the occurrence of a predetermined number of track crossing pulses, the detection of which causes iterative generation and application of braking current pulses to the head actuator motor. The amplitude and duration of each braking current pulse is chosen to cause forward motion of the head to be retarded to a predetermined percent of its pre-existing velocity. The microprocessor routine includes provision for iteratively determining when the head has slowed to a velocity which allows the track following servo to acquire control of the head. Once stopped on a track, a short seek is executed to return the head to the desired target track. Provision is also made in the microprocessor routine to iteratively determine direction of head movement to complement the polarity of the braking current pulse in the event a previous pulse has reversed the direction of head movement thus assuring that the braking current pulses always result in retarding forward motion of the head.