US 1632769 A
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`June 14 1927.
c. SEVERIN FILAMENTFOR INCANDESCENT LAMPS OR `SIMILAR ARTICLES Filed D90. 4. 1926 C/l. TURN-STI??? /NCH INS/ENIUH. CARL SE1/:ERIM
'Parental June 14, 1927.
UNITED STATES PATENT OFFICE.
CARL SEvERIN, OF CLEVELAND HEIGHTS, OHIO, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A. CORPORATION F NEW YORK.
FILAMENT FOR IE'CANDESCENT LAMPS OR SIMILAR ARTICLES.
Application led December 4, 1926. Serial No. 152,699.
My invention relates to electric incandescent lamps and similar devices comprising a filament or other energy translating body and more particularly to the said filament or '5 translating body per se. Still more particularly my invention relates to coiled aments which have a U or V shape comprising two straight leg portions connected by a bend portion. l v It is desirable inthe case of coiled filament to have a uniform spacing of the turns since this causes the various portions of the filament to be heated to a uniform temperature, thus avoiding hot spots. The practice has been to deliver the straight sections of the coiled filaments to the operator for mounting who, in the process of mounting, bends the lament in the desired shape. Heretofore in the straight sectionsof the filament thus ap lied, there has been a uniform spacing o yturns and the mountin causes an ununiform spacing since the ben `ing of the filament causes the coils at the bend portion to come closer together on the inside than do the coils on the extreme ends or leglportions. I have found that by spac- 4 ing t end portions and comparatively far apart at the intermediate portions of the straight sec- `3o tions of the filament, that coils inside of the bend portion will be spaced apart substantially the same distance as the coils in the lelportions.
the drawing, Fig. 1 is an elevation of B5 an electric incandescent lamp comprising a filament made in accordance with my invention; Fig. 2 is an enlarged elevation of a mounted filament; and Fig. 3 is a partially broken away elevation of a straight section 40 of a lament ready for mounting.
In the drawing the filament 10 is of coiled metal, ordinarily tungsten, and is mounted upon the rigid .conducting supports 11-12 which are 'united to the leading-in conductors 13-14 sealed into the flattened portion 15 of the glass stem 16, said stem bein sealed into a lamp which comprises the usua vturns e coils more closely together at thel bulb 17 and base 18. As shown in Fig. 3, the straight section of filament consists of a coil ordinarily of drawn tungsten. The coil is wound with a variable pitch, that is, the spaces of the coil are narrower at the ends of the section than in the middle. as indicated in the drawing. The number of per inch runs from one hundred twenty-five at the extreme ends to one hun- Adred at the middle portion. When such a lament'is mounted in the U shape, as shown in Fig. 2, there is substantially uniform spacing of the coils around the inside of the filament. .This result can be obtained Vfor various sizes of filament. By suitably varying the spacing of the coils, a uniform spacing may be secured in filaments of varlous sizes and shapes. 1
What I claim as new and desire to secure by Letters Patent of the United States, `is,
1. In an electric incandescent lamp or similar device, a coiled filament comprlsing two leg portions connected by an intermediate or bend portion and having its coils substantially uniformly spaced from each other along the inside the filament.
2. The method of making and mounting bent coiled filaments for incandescent lamps and similar devices which consists in coiling said filament with a variable pitch-such that the coils are more .widely spaced at what is to be a bent ortion, and then bending and mounting sa1d filament on its supports.
3. In the manufacture of incandescent lamps and similardevices comprising a filament and supports therefor, .the method4 which consists in coilin said filament with a variable pitch such t at in the intermediate portion of the filament the coils are more widely spaced than in the end portions, and then mounting said filament on said supports so that it assumes a substantially U shape. y
In witness whereof, Iy have hereunto set my hand this 1st day of December,'1926.