Inlead construction for electric lamp

• Main Authors: MCMILLAN; JOHN E, PIKUS; FRANCIS W, PUGH; JOHN W, GRAVES; JAMES A, WALTER; JOHN L
• Format: Patent
• Language: English
• Published: 15.11.1983
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRIC INCANDESCENT LAMPS; ELECTRICITY

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.