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:
Aug. 27, 2002
Filed:
Mar. 27, 2000
Tatsuhiko Saito, Yokohama, JP;
Tomomi Moriya, Yokohama, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
In a method of elongating a glass preform comprising the steps of holding both ends of the glass preform with a first holding section and a second holding section , respectively; moving the first holding section and the second holding section in a longitudinal direction of the glass preform with the moving speed of the first holding section faster than that of the second holding section and, at the same time, heating and softening the glass preform by a heating section successively; and elongating the glass preform by a tensile force applied thereto, so as to form an elongated body ; an electric furnace is employed in the heating section ; and said method further comprising the steps of setting a reference value R with respect to an outside diameter at a specific position in a tapered region in the glass preform in the process of elongating; acquiring an actually measured value R at the specific position ; and controlling the moving speed of the first holding section and/or second holding section according to a value (R /R ) obtained from the reference value R and actually measured value R