Electric lamp and discharge devices – Electrode and shield structures – With lead wire or connector
Reexamination Certificate
1998-12-08
2001-02-20
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
Electrode and shield structures
With lead wire or connector
C313S333000, C313S271000
Reexamination Certificate
active
06191526
ABSTRACT:
The invention relates to an electric lamp with a lamp bulb and at least one incandescent coil filament disposed in the lamp bulb as well as with electric current leads connected to the incandescent coil filament.
BACKGROUND OF THE INVENTION
An electric lamp of such type is disclosed, for example, in Japanese Utility Model 49-37 422. This utility model describes how an incandescent coil filament is fastened on a current lead-in wire provided with a flattened, U-shaped end. In their connection region the two legs of the U have reduced wire thickness and thereby form a seat, which is matched to the coil-filament diameter and in which there is disposed an uncoiled end of the incandescent coil filament. Outside the seat the two legs of the U are in contact with each other, and so the seat for the uncoiled end of the incandescent coil filament resembles the eye of a needle.
SUMMARY OF THE INVENTION
The object of the invention is to provide an electric lamp with improved fastening between incandescent coil filament and its current lead.
In the electric lamp according to the invention, the incandescent coil filament is fastened and provided with electrical contacts by means of current lead-in wires having a flattened, U-shaped end. The two legs of the U-shaped current lead-in wire segment form a gap in which a coiled end of the incandescent coil filament is disposed. The gap width is smaller than the outside diameter of the coiled end of the incandescent coil filament, and so the incandescent coil filament is held clampingly in the gap-like seat. The gap width is advantageously 60 to 90% and preferably 70% of the outside diameter of the coiled end of the incandescent coil filament. Thereby there is achieved secure fixing of the incandescent coil filament to the current lead with only slight deformation of the coil filament. In order to prevent bending or opening of the legs of the U, the ends of the legs of the U are advantageously welded together with each other in two practical examples of the invention, while in a further practical example the end of the free leg of the U is welded together with the non-flattened segment of the current lead-in wire for this purpose. In a preferred practical example (FIG.
4
), the free leg of the U has an angled end, which is welded together with the other leg of the U. Thereby the gap width can be varied within certain limits for given wire thickness and degree of flattening of the current lead-in wire. The end of the incandescent coil filament projecting beyond the legs of the U is advantageously welded together with the current lead-in wire. Thereby there is achieved good electrical contact and low contact resistance between incandescent coil filament and current lead-in wire. The invention is suitable in particular for fastening doubly coiled incandescent coil filaments having singly coiled ends.
REFERENCES:
patent: 2145186 (1939-01-01), Meeker et al.
patent: 2315504 (1943-04-01), Curtis
patent: 3780333 (1973-12-01), Flynn
patent: 690 735 (1940-04-01), None
patent: 5-182641 (1993-07-01), None
patent: 6-231736 (1994-08-01), None
Kiesel Rolf
Minder Rolf
Frishauf, Holtz Goodman, Langer & Chick, P.C.
Guharay Karabi
Patel Nimeshkumar D.
Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen MBH
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