US819624A - Incandescent electric lamp. - Google Patents

Description

No. 819,624. PATENTED MAY 1, 1906. H. I. WOOD.

INGANDESQENT ELECTRIC LAMP.

APPLICATION FILED OUT. 31, 1904.

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UNITED srn'rns PATENT enrich.

HOWARD I. WOOD, F SCHENEGTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

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The invention herein described relates to incandescent electric lamps orsimilar apparatus, and more especially to the means whereb current is conveyed through the walls 0 the glass bulb or envelop. Instead of securin the vacuum-tight joint by metal, such as p atinum, having substantially the same coefficient of expanslon as glass, I make use of a ring or similar device of co per,'iron, or other sultable metal shrunk tig tly about a portion of the glass envelop 'and forming therewith a perfectly vacuum-tight joint. Electrical connection is made with such a ring by means of a wire or conductor passing through the glass and engaging said ring.

The novel featureswhich characterize .my invention I have pointed out with particularity in the appended claims. a

The invention itself, however, will be better understood by reference to the following description, taken in connection with the ac' companying drawings, in wh1 ch 1 Figure 1 1s a pers ective new of an moandescent lamp embo ying my invention. Fig. 2 is a modification; and Fig. 3, a sectional view of a portion of Fig. 2..

Referring to the drawings, more especially to Fig. 1, the art numbered 1 re resents the lass bulb of an incandescent amp. The

ower portion of this bulb may'be of tubular.

form, as at- 2. Internal current-conveying conductors which support the-usual filament 3 are indicated at 4 and 5. The upper ends of these conductors are held in fixed relation to each other by a ball or mass of glass 6, fused about them. Theilower ends of the conductors are passed-through thev walls of the tube 2 at 7 and 8 and are bent around for a short distance in contact with the outer wall of the tube, as at 9 and 10, respectively. The openings 7 and 8 may be'such that the conductors 4 and 5 pass loosely therethrough or the walls of the openings may, if desired, be sealed about the conductors. In either case, however, the joint of itself is unavoidably leaky. In order to secure a tight joint,

Specification of Letters Patent. Application filed October 81, 1904. Serial No. 230,725.

the metal rings or bands.

Patented may 1, 19060 I seal about the tubular portion 2 apair of rings 11 and 12, one of which is shrunk about the tubular portion so as to engage the end 9 of the conductor 4 and the other so as to engage the end 10 of the conductor 5. These rings or hands are preferably of metal having a higher coefficient of expansion than that of glass and may be formed conveniently of copper, iron, suitable alloys, or the like. The are of such diameter that they may be eas' y passed over the tubular portion 2 to the position desired. After the rings are, placed in position, either one at atime or both together, the parts are then heated in the ordinary glass-blowers gas-jets to a temperature, such as a red heat, 'at which the glass becomes soft. Air-pressure is then exerted to force the glass into intimate contact with been accomplished, the parts are allowed to When cool, the .metal bands, having a larger coefficient of expansion than the glass,

necessarily contract faster, and thus shrink tightly about the glass and form an exceedingly tight joint. The entrance'of air into the lamp-bulb through the passages afforded by the openings 7 and 8 is thus effectually prevented. v i

In order that the glass may not be cracked or sheared by the force of contraction of the metal bands, it is necessary that themetal be thin enough to stretch in response to the' resistance to compression afforded by the lass. A thickness of metal ofabout one oneundredth of an inch will be found satisfactory for this purpose, though of course this may vary somewhat, dependent upon the thickness and shape of the glass portion about which the bands are placed.

Instead of employing two bands or rings I may,,as shown in Fig. 2, utilize but a single band and effect the desired. connections, as shown in this figure.

The tubular portion of the incandescentlamp bulb is indicated at 12. The filamentcarrying conductors 13 and 14 pass through the wal s of the bulb, as at 15 and 16, and are bentaround on the outside, as indicated at 17 and 18. A plate of metal 19 is placed over'the conductor end 18, so as to make contact therewith. A sheet of mica 20 is placed over this metal plate, and then around all is mounted a ring or band 21, of metal, a

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portion of which contracts with the conductor end 17 of the conductor 14.. The parts blown into intimate contact with the metal parts which are in juxtaposition therewith. Upon cooling, the metal band 21, which'as in the similar construction in Fig. l is thin, contracts yieldingly about the glass and formsa perfect joint therewith, so as to prevent the entrance of air about the points 15 and 16,

where the conductors 13 and 14 pass through the lass tube 2.

E ectrical connection to the conductor 14 is made with the ring or band 21 and for the other conductor 13 with a lead 22, connected to plate 19. As already indicated, this plate 19 while making electrical connection with the conductor end 18 is insulated from the metal band 21 by the plate 20, of mica, ashestos, or other suitable refractory insulating material.

What I claim as new, and desire to secureby Letters Patent of the United States, is

. 1. The combination of a vitreous envelop, a thin metal band shrunk, while the parts are hot, about a portion of the envelop so as are then heated, as before, and the glass.

to make intimate contact therewith, and a metal conductor or wire passing through the envelop from the inside and making contact with the band or ring on the outside.

2. The combination of a vitreousenvelop, conductors passing through the walls of said envelop from the inside, and external-connections for said conoluctors formed in the 'case'of one conductor of a metal plate or sheet and in the case of the other conductor of a sleeve or band, said plate or sheet and said sleeve. or hand both forming vacuumtight joints with the envelop.

3. A seal for incandescent lamps, which consists of a sleeve or band of thin metal in intimate contact with the glass portion of the lamp, and a conductor passin throu h the glass and engaging the inner si e of sai band or sleeve.

I In witness whereof I have hereunto set my hand this 29th day of @ctober, 1904:.

HOWARD l. WQOD.

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