EP 0271857 A2 19880622 - Compact coiled coil incandescent filament with supports.
Title (en)
Compact coiled coil incandescent filament with supports.
Title (de)
Kompakte Doppelglühwendel mit Haltern.
Title (fr)
Filament incandescent bispiralé compact muni de supports.
Publication
Application
Priority
US 94233986 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 4.00 and a secondary mandrel ratio which is greater than or equal to the primary mandrel ratio. The length between supports is kept less than or equal to 20 times the secondary diameter. 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 0271857 A2 19880622; EP 0271857 A3 19900516; EP 0271857 B1 19970402; DE 3752039 D1 19970507; DE 3752039 T2 19971030
DOCDB simple family (application)
EP 87118489 A 19871214; DE 3752039 T 19871214