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. 20, 1977
Filed:
Jun. 04, 1976
James J Auborn, Groton, MA (US);
Elizabeth Ann Trickett, Acton, MA (US);
GTE Laboratories Incorporated, Waltham, MA (US);
Abstract
A mandrel and a method for its manufacture and its use in manufacturing filament coils for electric lamps is disclosed. The mandrel, having a base core containing iron, is protected from diffusion of iron into a filament wire wound thereabout by a first coating of copper and a second coating of tungsten over the first, base metal. The process of coating the tungsten over the copper coating is improved by employing small amounts of copper ion contaminant in the electroplating solution. After a filament wire is wound around and annealed over this mandrel, the mandrel is selectively dissolved leaving the shaped filament coil, substantially free of extraneous metal impurities.