General Electric Company

John T Pastir

Ronald James Olwert

A method of establishing coil dimensional stability by thermally stress relieving the tungsten filament prior to mounting in a lamp. The filament is manipulated into the desired position by coiling it first around a primary mandrel, then a retractable secondary mandrel. After the secondary mandrel is removed, the filament is held in place by a pair of electrical contacts. A current is passed through the primary coil, which heats the tungsten and causes it to recrystallize. The recrystallization provides the desired dimensional stability.

Method of dimensionally stabilizing a tungsten filament

A method and apparatus for more precisely centering lamp leads ( ) uses a support mechanism ( ) for radially aligning the leads. The support mechanism is a helical member having first and second helical portions ( ). The first helical portion has a diameter slightly less than the inner diameter of the lamp envelope to maintain a filament ( ) on axis. The second helical portion has an outside diameter less than the outside diameter of the first helical portion for securing the support mechanism to a mounting mechanism ( ). Here, the mounting mechanism is preferably defined by first and second flattened portions ( ) integrally formed on the lead that axially positions the support mechanism in place.

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Eastlake, OH, United States of America

John T Pastir