US2184269A - Base for incandescent lamps and similar devices - Google Patents

Description

Dec. 26, 1939. c. A. BROWN El AL 2,184,269

BASE FOR INCANDESCENT LAMPS AND SIMILAR DEVICES Filed May 14, 1938 Inventors:

Carl A- Brown, Clarence E. Hahn,

The'n Attorn' ey.

,. eiee e .Dee 19 9 i I fiaisiacc f,

else 'jij ocjiucm; ejceiiii .1 .s-i ,s ,oar'i a BrownfCha'rdon. and clarcnccnli. Hahn; Cleveland;Ohio,v assigirorsjtoaGeneral Electric company, acorporation of -New, York diipllcatlonlglayll'i. ia3a'.f senai ne; 207,965

x0111 invention relates toielectric 1nca1{des' en." t hh,i8lhdthe bras sj'shell orfiend zcontactyeyelet. .2 lamps; and similar devices comprising'a bulbjhavf such a'rigid'inspection necessitates-a large in- 1 an electrical energy; translation; element spectio'n'ior'ce; which thereforefurthen increases sealed therein and a base mounted 'on'sald bulb. Qthe costjof'productionb i '5, More particularly, our, invention. relates to bases, Byri fif 'mih l' glass insulation a a .sepafor such devices which usually consist of a me ate rhemberand'then mechanicallysecuring the 1;, tallic shelland -a bottomerid contact separated bra's shell thereto, the above-mentioned-disadfrom each other by a suitable insulating medium; vantages'are entirely obviated; "Accordingly, one In the presentmethod smanufacturingiama objectfot our invention is to'provide a base, con- .10' bases, a brass shell and acenter or end contact f struction' for electric lamps and similarrdevices ;-.;eyelet are first placedin a suitable moldand as in which the glass insulation consists of a sepa- 'definite quantity oi molt en glassipoured'there lFetelmfollllsd'Infinite!ill/111M115therssftelimeinto. A-plungerthenpresses the molten glass 'chanically securedto' the brass shelln s 1 into the desired shape and into firmen gagement Another object of our invention is the-proviwith the brass shell and, yelet t th fbyf [sion'oi positive interlocking means between the 15 the completed base. flhejhotglasalhowever, an-' ,f base shell and the"preformed-:glass' insulation neals the brassshell so-that it is undesirably memberemp ye j Our i proved basev consoftened to the point where it is readily deformstruction whereby relative rotational-displaceable, To partially compensate for theresulting ment between the'said parts is positively elimidecrease in strength or the ,shell,,filldtoinainhated; m

tain the tshell vrtrengt h .aboy'e certai mi im m f A further object of our inventlon is th iprovi- ,limits, it is therefore necessary to'eniployibrass sion of a preformed; glass insulator button for a a material of greater thickness than would be the lamp b se th periphery of which button is r case-lino suchannealirig actionwere' present. r d w t a plurel y f p i n 's shaped As a consequencelthe amount, and therefore the as i and breakage during the rolling v 25 cost, of the brass,ma terialj is considerably of the brass rhell onto said projections and to greater than'it would be, if 'no'such shell annealorm a firm interlock between the brass shell ing occurred. F rthermore, the brass shell is 4 and t e class buttons a I considerably tarnished or discolored by the heat Further objects and advantages of ourzinvenof the molten glassduring the formation of the 131011 w l pp from the following description 30 base structure, thereby necesitating an opera-Y "of a species t e o and from the accompanying tion commonly known as a bright-dip which drawin in Whitiht v consists in dipping the completed bases in a suitg- 1 is a fragmentary side View, P y in able acid bath, such as sulphuric and nitric acids, tion, of an electric incandescent lamp provided to remove the said discolorations and restore the w t a b se comprising 11 invention; 2 is 35 original brightness of the brass shell and eyelet. an enlarged fragmentary sectional view taken on A considerable quantity of brass is removed from e ne of 3 is a p View Of a the shell during this bright-dip operation, therepreformed glass insulator button according to by resulting in a considerable waste of material our invention; an 4 is an a d se t ona 40 and so further increasing the cost of manufacview taken on the line 4-4 of Fi 40 ture. Also, the acid etches the brass shell un- Referring to the drawing, there is shown in equally, etching the grain boundaries much Fig. 1 an electric incandescent lamp Comprising 8 deeper than the grains themselves, so that the bulb l0 havin filament (not shown) sealed original thickness of the brass must be suffitherein and a base H attached to the neck ll of cient to compensate for such unequal etching in the bulb by'sultable cement The base it 45 order to maintain the strength of the shell above consists of a threaded metallic shell l P certain minimum limits. A further disadvanably of brass, to with insulation '5, a tage of the above described process of manufacbottom end contact IS. The insulation is prefturing bases lies in the fact that the completed era ly mad f glass, although y other su tab e bases must be thoroughly inspected for a conma e y b employed- One 8nd of the p 50 siderable number of objectionable defects, such filament is connected to the base shell by means as missing eyelets, plugged eyelets, slanting or of a lead I! bent back over the end of the bulb displaced eyelets, threads of glass extending over neck and soldered at l8 to the edge of the said the edge of the shell, too much glass insulation, shell. The other end of the lamp filament is a or an insecure bond between the glass insulaconnected to a lead H which extends through a 55 centrally located opening in the glass insulation where the said lead is Secured by means of a drop of solder I6 to thereby form the bottom end contact. The recess 2| in the glass insulation I5 is preferably shaped in the manner described and claimed in our co-pending application Serial No. 207.964 of even date herewith.

The glass insulation I5 according to our invention is made as a preformed member and is secured to the base shell It by mechanical interlocking means. Referring to Fig. 1, the outer end of the base shell H is provided with a reentrant flange 22, the inner edge of which is bent inwardly to form an annular ledge or seat 23 on which the preformed glass button I5 is mounted. The upper or outer convex surface 24 (Fig.4) of the glass button l5, adjacent the periphery 25 thereof, is formed with a plurality of uniformly spaced crescent shaped projections or lugs 26. The upper surfaces 21 of these lugs are substantially flat and lie in a plane approximately parallel to that of the seating surface 28 on the glass button, while the side surfaces 29 of the lugs are formed substantially as continuations of the periphery 25, as shown in- Fig. 4, and are curved on a radius of preferably one-sixteenth inch or thereabouts.

In assembling the preformed glass button l5 and the base shell II, the button is simply placed in position on the annular seating flange 23 and the upper edge 30 of the base shell isrolled or peened over the various projections 26 by means of a suitable forming tool,.such as a roller or cam. The pressure so applied to the edge 30 of the base shell results in a deformation of the reentrant flange 22 whereby the same conforms to and engages the curved side surfaces 29 of the various projections 26, as shown in Fig. 2, as well as'the upper surfagces 21 of the same. To insure such a deformaition of the re-entrant flange 22 without a corresponding deformat on of the outer edge or wall 30 of the base shell, the projections 26 on the glass button are spaced a definite distance apart. Thus, as shown in Fig. 3. a button l5 having a diameter of approximately seven-tenths of an inch is preferably provided with twenty such projections 26 around its circumference so that the same will be spaced approximately eleven-hundredths of an inch apart. With such an arrangement, a positive interlock between the brass shell I4 and the glass button I5 is assured whereby relative rotative displacement therebetween is entirely prevented. In addition, the projections 26 are sufllciently strong so as not to become broken during the rolling over of the shell edge 30 onto the said projections.

As stated previously, the use of the preformed glass insulator button I 5 greatly simplifies the production. of lamp bases and materially decreases the cost of manufacture thereof. The internal strains in such a button can be removed by annealing the same prior to its assembly with the brass shell so that the latter is not softened and tarnished by the heat attending such annealing operation. Since no discoloration of the brass shell occurs, the customary bright-dip operation may be dispensed with, thus permitting the use of thinner material for the brass shell. The use of a drop of solder as the bottom end contact eliminates the customary brass eyelet, thereby resulting in a further saving of brass. Finally, the use of a preformed insulator button eliminates a considerable number of the defects for which bases have been heretofore inspected, with a resulting decrease in the cost of inspect-ion.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A base for electric lamps or similar devices comprising a metal shell and a preformed insulator button at'the upper end thereof, said button having a convex upper surface with a pinrality of small spaced crescent-shaped projections at its periphery, said shell having at its upper end a re-entrant flange portion terminating in an inwardly extending flange forming a seat for the periphery of said button, the upper portion of said re-entrant flange being deformed to conform to the shape of the periphery of said button including the curved sides of said projections and overlying the upper surfaces thereof, the interengagement of said flange portion with the sides of said projections preventing relative rotational movement between said shell and button, and the periphery of said button being firmly clamped between the said inwardly extending flange and the portion of said re-entrant flange overlyingsaid projections.

2. A base as set forth in claim 1 wherein the insulator button consists of a vitreous material.

CARL A. BROWN. CLARENCE E. HAHN.

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