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:
Jul. 25, 1989
Filed:
Jul. 25, 1988
Paul B Stumpf, Rochester, NY (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
In a disk memory library, picker arms, operated by a solenoid, are used to remove a selected disk from a library stack of disks and to place the disk in a reading/writing environment. The solenoid plunger's position is determined by noting its effect on a series resonant circuit that is formed with the coil inductance of the solenoid coil and a series capacitor. A function generator provides a triangular signal to the solenoid coil. An amplifier and peak detector are coupled to the coil to amplify and peak detect the voltage signal across the coil. A threshold detector, coupled to the output of the peak detector, is set to provide a digital output indicating when the solenoid's plunger is in or out. The function generator also provides a square wave that is synchronized to the triangle wave and is coupled to sample the output from the threshold detector. The change in the coil's inductance causes a phase shift in the triangle wave which further accentuates the voltage difference appearing across the coil. The output from the synchronous detector is used to determine when the plunger is in or out and, in turn, when the picker arms are extended or retracted.