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:
May. 17, 1977
Filed:
Nov. 14, 1975
William Thomas Boston, Melrose, MA (US);
Optronics International, Inc., Chelmsford, MA (US);
Abstract
A method and apparatus are disclosed for referencing the position of a rotatable drum in a scanner/plotter. The rotatable drum is rotatable held in axial alignment by means of a drum headstock and a spring loader, moving center tailstock. An optical shaft encoder provides a reference pulse for the headstock drum shaft and a plurality of drive shaft position pulses. The rotatable drum has a magnetic pellet mounted thereon. A magnetic transducer is positioned with respect to the predetermined drive shaft position to detect the presence of the drum pellet. As the drum rotates, the transducer detects the pellet and produces an output signal which is used to electronically cross-reference the drum pellet to the predetermined drive shaft position.