General Electric Company

James A Graves

Gilbert H Reiling

Francis W Pikus

John L Walter

John E McMillan

John W Pugh

This invention relates to a single strand filament wire arranged into a triple-coil filament for an incandescent lamp. The triple-coil filament has selected dimensions that do not require recrystallization of the tungsten wire of the triple-coil filament prior to arranging the triple-coil filament within the incandescent lamp.

Triple coil incandescent filament

An improved inlead construction for an electric lamp is disclosed which utilizes an iron alloy containing sufficient silicon to avoid transformation of the inlead from the alpha ferrite phase to the gamma austenite phase at lamp operation temperatures. This precludes debilitating deformation of the inlead wires caused by on-off cycling of the lamp and concomitant cycling of the wire through the alpha to gamma transformation range. Such deformation can lead to structural or operational failure if the inleads become disconnected or electrically shorted from the resistive filament during lamp operation. In a preferred lamp construction, a pair of the improved inlead wires serve as the sole means of physical support for a resistive incandescent filament directly connected thereto and said inlead wires can further be coated with a dissimilar metal for higher lamp loading requirements in order to help avoid iron migration which can produce deterioration of the resistive incandescent filament.

Inlead construction for electric lamp

This invention relates to multiple coiled incandescent filaments and more particularly to a single strand filament wire, coreless, triple-coil filament for an incandescent lamp having mandrel ratios in either or both its second or third coiling less than 1.0.

Triple-coil incandescent filament

An electric lamp construction is described having a pair of conductive inlead wires of dispersion-strengthened copper alloy to serve as the sole means of physical support for a resistive incandescent filament electrically connected thereto, wherein said inlead wires have a surface metallurgical structure of fibrous dispersion-strengthened copper alloy. Said metallurgical surface of the inlead wires can further serve to enhance bonding of other materials thereto including metals such as nickel and aluminum as well as nonmetallic gettering materials such as phosphorous compounds.

Electric lamp having improved inlead construction

Lead wires having a specified stiffness, ie. stress/strain, characteristic are described for use in an incandescent lamp.

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Highland Heights, OH, United States of America

James A Graves