EP 0271859 A2 19880622 - Compact coiled coil incandescent filament using pitch for sag control.
Title (en)
Compact coiled coil incandescent filament using pitch for sag control.
Title (de)
Kompakte Doppelglühwendel mit Anwendung der Steigung für Biegungskontrolle.
Title (fr)
Filament incandescent bispiralé compact utilisant le pas pour contrÔler l'affaissement.
Publication
Application
Priority
US 94233286 A 19861216
Abstract (en)
This invention provides an improved compact fine wire incandescent lamp filament and method for making the same. The filament has a primary mandrel ratio in the range of about 1.40 to about 3.00 and a secondary mandrel ratio which in the range of about 3.0 to about 10.0. The improved filament design exhibits an increase in compactness and retains or increases structural rigidity while exhibiting minimal sag when the filament is incorporated into an incandescent lamp of the tungsten halogen type variety. The compact coiling method is particularly useful in designing compact filaments for high voltage applications where it is desirable to eliminate the use of rectifying means to lower the effective voltage across the filament.
IPC 1-7
IPC 8 full level
CPC (source: EP)
Designated contracting state (EPC)
BE DE FR GB NL
DOCDB simple family (publication)
EP 0271859 A2 19880622; EP 0271859 A3 19900509; EP 0271859 B1 19970402; DE 3752040 D1 19970507; DE 3752040 T2 19971030
DOCDB simple family (application)
EP 87118491 A 19871214; DE 3752040 T 19871214