US759506A - Means for and method of securing lead-in wires in electric lamps. - Google Patents

Description

No. 759,506. 7 PATENTED MAY 10 1904.

J. C. ENTRIKE N & W. S EVERETT. MEANS FOR AND METHOD OF SECURING LEAD-IN WIRES IN ELECTRIC LAMPS.

APPLICATION FILED JAN. 21; 1904.

H0 MODEL.

INVENTORY,

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No.759,506. l PatentedMay10,190;.

UNITED STATES PATENT OFFICE.

JOHN (J. ENTRIKEN AND WILLIAM S. EVERETT, OF MALVERN, PENNSYL- VANIA, ASSIGNORS OF SEVEN-SIXTEENTHS TO CHARLES F. KINDRED, OF PHILADELPHIA, PENNSYLVANIA.

. MEANS FOR AND METHOD OF SECURING LEAD-IN WIRES IN ELECTRIC LAMPS.

SPECIFIGATIONforming part of Letters Patent No. 759,506, dated May 10, 1904.

"Application filed January 21, 190A. Serial No. 190,072. (No model.)

T all whom it y COW/067': fusing the glass also fuses the thin terminal Be it known that We, JOHN C. ENTRIKEN and wires. The size of this wire, therefore, must "l/VILLIAM S. EVERETT, citizens of the United necessarilybe increased in order to sufliciently States, and residents of Malvern, county of resist the heat of the flame used in the fusing 5 Chester, State of Pennsylvania, have invented operation; but, in the second place, when this certain new and useful Improvements in Means is done it is found that th e glass adjacent to the for and Methods of Securing Lead-In Wires end of the terminal section becomes cracked in 5 5 in Electric Lamps, of which the following is a cooling, thereby breaking the seal, and thus specification. destroying the vacuum.

IO Our invention relates to electric lights, such We have discovered a means and method as incandescent electric lights, and more parwhereby the terminal section of'a lead-in wire ticularly to improvements in the means and composed of two such sections-ofmetal can method of securing lead-in wires to the stem be made as thin as desired, thereby securing 'of such lights. all the advantages sought to be attained by I5 That part of the lead-in wire which is emthe specified method of manufacture, and in bedded and sealed in the glass of the stem of utilizing our discovery We provide an electric an electric lamp must be made of a metal havlamp with a lead-in wire composed of two sec- 5 ing a coefficient of expansion substantially the tions of different metals, one having'substansame as that of glass, for reasons which are tially the same coeflicient of expansion as glass 20 Well-known in the art. The metal employed and the other a different coefficient of expanfor this purpose is platinum or an alloy of sion, which obviates the objections hereinbeplatinum with one of the platinum group. fore specified.

The cost of such metal is very high and eon- Our invention therefore consists in the novel 'stantly increasing, and consequently attempts means of securing a lead-in wire to electric 5 have been made to reduce the amount of platilamps and in the novel method of manufacnum necessary for the purpose by reducing the ture as hereinafter described, with reference diameter of the wire as Well as its length. to the accompanying drawings, and'more par- One plan proposed is that wherein the lead-in 'ticularly pointed out in the claims. wire is composed of two metals having diifer- In the drawings, Figure 1 is a side eleva- 3 ent coefficients of expansion, one of them, such tion of an electric lamp embodying our invenas platinum, having substantially the same cotion. Fig. 2 is a central vertical section of eflicient of expansion as glass. The platinum the stem thereof. Fig. 3 is a similar section 0 section in such construction is made of miniat right angles thereto. Figs. 4 and 5 are mum length and thickness and joined or fused both views in elevation, showing steps in our 35 to the other metal section which forms the new method of sealing the lead-in Wire in terminal for supporting the filament, and both the stem; and Fig. 6 is aperspective view of sections are sealed in the glass stem. This the protecting-cap preferably used in such 5 plan enables the reduction in the amount of method. platinum to a very great extent; but there ex- Referring to the drawings, in which the 4 ist practical objections which inhibit its use. same reference characters relate to the same In the first place when the terminal section of or corresponding parts in all the views, the the lead-in wire is made sufliciently thin for lamp-bulb 1, in which the vacuum is mainthe purpose it has been found to be impossible tained, is provided 'with the usual stem 2, to conduct the sealing and compressing steps through which pass the conductor-Wires 7 45 without destroying the terminal section, be- To each of these wires is joined or fused a cause when the small end portion of the glass lead-in wire composed of platinum or other stem is heated and then compressed to seal equivalent metal or alloy, to each of which is the wires therein the high heat necessary for fused the terminal section 5 of the lead-in wire, composed, preferably, of copper or some cheaper metal than platinum, such terminal sections extending through the bulb end of the stem. The short section 6 of platinum is embedded and sealed in the lower portion 3 of the glass stem, the joint between said short section and the terminal section lying, preferably, just within the mass of glass 3, from which extendsalimited portion 4 of the glass stem, forming a recess terminating the stem at its bulb end and the wall of which is free from contact with the terminal sections.

In producing the construction described we direct the flame for fusing the glass against a limited area of the stem inclosing the platinum section in such manner as to prevent it from coming in contact with the terminal sections 5, thus avoiding such undue or high heating of the latter sections as would tend to fuse the same, and to better effect this purpose wc -pre fer to use a protecting perforated flanged cap 8 of oblong shape, which is placed in the lower end of the stem 2, supported in holders 10, mounted on the usual carrier, as shown in Figs. 4: and 5, the flange of which rests against the lower end of the stem and is held there by any suitable means. Through the perforation in the cap the wires 5 pass and are therefore inclosed by the said cap, preventing the flame from the gas-jet 9 from coming in contact therewith. WVhen the glass is sufficiently heated, the usual compression is employed to compress the glass and embed the sections of the lead-in wire therein, the cap 8 serving to prevent the bulb end t of the stem from being massed together, and thereby forming a recess at the bulb end of the stem, as seen in Fig. 5, where the stem is shown with wires attached and cap 8 removed after compression.

While we prefer to use a cap as a protector for the wires 5 during the process of sealing, this cap may be dispensed with if proper care is taken to direct the flame against the stem in such a way as to prevent it from fusing the terminal sections 5. It is preferable, however, to so protect the terminal wires from the flame as to keep them free from contact with the glass in the finished product, as this construction has the advantage of not only rendering the operation easier to perform, but also of obviating the possibility of breakage of the sections 5 should the latter be bent in any direction, because such bend at its point of emergence from the glass, where liability of breakage occurs, cannot be sharp enough to cause such breakage, as is the case where the bend takes place close to the point where the wire is embedded in the glass, for the edge of the wall of the recess prevents the sharp bending of the wires at the point where they emerge from the mass of compressed glass. The flame, it is to be noted, should be directed against a limited area of the lower partof the stem inclosing the lead-in wires and should not be allowed to reach below the bulb edge of the stem in order to prevent its high heating action on the terminal sections, and this can always be the better insured by protecting the terminal sections as hereinbefore described or in some equivalent manner.

e claim as our invention- 1. In an electric lamp, a stem through which the lead-in wires pass closed at its bulb end and terminatingin a recess therein, said leadin wires being composed of sections of different metals, one of which has a coefficient of expansion substanially the same as the material of the stem and embedded therein and the other constituting the terminal sections united to the embedded sections and extending through the recess into'the lamp-bulb, substantially as described.

2. In an electric lamp, a stem through which the lead-in wires pass closed at its bulb end and terminating in a recess therein, said leadin wires being composed of sections of platinum embedded in the mass of the stem and a metal of different coefficient of expansion eonstituting the terminal sections united to the platinum sections and extending through the recess into the lamp-bulb, substantially as described.

3. As an improvement in the art of securing lead-in wires to the stem of an electric lamp, the method which consists in placing in the stem lead-in wires composed of two sections of different metals united together, one havinga coefficient of expansion substantially the same as the material of the stem and inclosed by the stem, and the other constituting the terminal wires extending through the bulb end of the stem, then fusing the stem by heat applied to a limited area of the stem near its bulb end, protecting the terminal wires against fusion during such application of heat, and compressing the fused mass of the stem to embed the lead-in wires therein, substantially as described.

4. As an improvement in the art of securing lead-in wires to the stem of an electric lamp, the method which consists in placing in the stem lead-in wires composed of two sections of different metals united together, one having a coefficient of expansion substantially the same as the material of the stem and inclosed by the stem, and the other constituting the terminal wires extending through the bulb end of the stem, then fusing the stem by heat applied to a limited area of the stem near its bulb end, applying a protecting-cap to the bulb end of the stem to prevent undue heating of the terminal sections, and compressing the fused mass of the stem to embed the leadin wires therein, substantially as described.

5. As an improvement in the art of securing lead-in wires to the stem of an electric lamp, the method which consists in applying to the stem lead-in wires composed of two united sections of different metals, one of said metals consisting of platinum forming sections to be embedded in the glass of the stem when sealed, and the other of a different coefficient of expansion constituting the terminal sections extending through the end of the stem into the bulb, applying heat to a limited area of the stem surrounding said platinum sections to fuse that portion of the stem, protecting the terminal sections against fusion by said heat, and compressing the fused portion of the stem to embed the wires therein, substantially as described.

6. As an improvement in the art of securing lead-in wires to the stem of an electric lamp, the method which consists in applying to the stem lead-in wires composed of two united sections of difierent metals, one of said metals having substantially the same coefficient of expansion as glass, and forming the sections to be embedded in the glass of the stem when sealed, and the other of a dilferent coeflicient of expansion'constituting the terminal sections extending through the stem into the bulb, directing a flame against a limited area of the stem above the end of the same and out of contact with the terminal sections, and compressing the fused portion to embed the wires therein, substantially as described.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

JOHN C. ENTRIKEN. WILLIAM S. EVERETT.

Witnesses:

G. H. EDWARDS, J. FOREMAN Cox.

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