Coiled-coil filament design for an incandescent lamp
US5680003A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1995 |
| Grant date | Oct 21, 1997 |
| Priority date | — |
| Expiry date | May 19, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01K1/16
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An improved coiled-coil filament for use in an incandescent lamp has a primary coil winding with a substantially uniform spacing between successive coil turns. The primary coil winding is wound around a second mandrel in a manner to provide a main coil body and leg portions extending therefrom. A helical bend is formed between the main coil body and the leg portions thereby allowing that the leg portions extend toward a seal region of the lamp envelope in a substantially parallel relation to each other. Once the main coil body has been set in shape, the first and second mandrels are removed such that the leg portions are disposed in the seal region of the lamp envelope in a spaceless, and optional spudless manner. In manufacturing the spaceless, spudless coiled-coil filament of the present invention, several manufacturing steps are avoided including the steps of Picco or wax dipping the ends of the leg portions to allow for the formation of the previously required spud members, and of removing the Picco or wax dip after the remainder of the primary mandrel has been dissolved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.