US2418179A

US2418179A - Base for electric lamps and similar devices

Info

Publication number: US2418179A
Application number: US485816A
Authority: US
Inventors: Elmer B Isaac; Francis J Rippl
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1943-05-06
Filing date: 1943-05-06
Publication date: 1947-04-01
Anticipated expiration: 1964-04-01
Also published as: ES177961A1; FR944675A

Description

April 1, 1947.- E. B. ISAAC ETAL BASE FOR ELECTRIC 'LAMPS AND SIMILAR DEVICES Filed May 6, 1943 2 Sheets- -Sheet l H 01: my w lnven't ors Elmer" B. Isaac, Francis J. RippL,

Their- A't'tor'neg.

April 1, 1947- E. B. ISAAC ETAL 2,413,179

BASE FOR ELECTRIC LAMPS AND SIMILAR DEVICES 2 Shee ts-Sheet 2 mi e ai n ap. T o J o 1TB .LL n .s k v m mmm Figs.

Patented Apr. 1, 1941 BASE FOR ELECTRIC LAMPS AND SIMILAR DEVICES Elmer B. Isaac, Cleveland Heights, and Francis J. Rippl, Cleveland, Ohio, assignors to General Electric Company, a corporation of New York Application May 6, 1943, Serial No. 485,816

(or. ire-s2) 16 Claims.

presents novelty in methods of manufacture or as well as The fabrication and in apparatus therefor, novelty in base and envelope structures.

invention permits of simplifying and lowering the cost of the base structure, of facilitating and lowering the cost of its manufacture and attachment, and of dispensing with soldering, welding, or other special operations in connecting the electrical device to the contact terminal means of the base.

In electric lamp manufacture, the general commercial practice is to fabricate as one unitary structure, separate from the lamp, a base comprising an external metal shelP' provided with means for securing it in a socket, and also with one or more end contact terminals which are exposed at one end of the shell and are secured to the latter by a body of thermoplastic insulation (usually glass) molded or otherwise fastened into the shell. This separate, unitary base is subsequently mounted and cemented fast around the sealed neck end of a lamp envelope or bulb; and current leads from the lamp bulb are connected to the contacts of the base by soldering or welding. One type of base is known as a "bayonet" base because its metal shell is equipped with bayonet pins for securing it in a socket; another .is known as a "screw" base because its shell is screw-threaded to screw into the socket. The screw shell customarily serves as a contact terminal of the base; the bayonet shell" may or may not be so used. Still other types of base are also employed.

In forms of our invention hereinafter described, we employ an external base shell or band for mechanically attaching the base directly to the lamp in such a way that the operation of attachment is also a principal step in the fabrication of the base itself. In a screw or bayonet base, the shell may be screw-threaded or otherwise equipped for coaction with a. socket, and means of antiturning engagement between the lamp or bulb and the base band or shell are provided, as well as means of shouldered engagement for holding the parts together. Besides the insulator that carries one or more contact terminals. The preferred method of fabrication and assembly is to cast the base band or shell around the bulb neck and the base insulator, and to embed any corresponding lamp lead in the cast metal. We have also devised a way of casting the end or center contact terminal means into a base insulator and embedding the corresponding lamp leads(s) in the casting(s)and this last method may even be employed in cases where the base shell does not in and of itself secure the base to the lamp bulb, but is cemented or otherwise attached as heretofore known in the art. In general, however, there need be no occasion for cementing, soldering, or welding to attach the base to the bulb or to connect its contact terminals to the lamp leads: on the contrary, these operations may merge in the mere casting of the band or shell and the associated contact(s).

Various other features and advantages of the invention will become apparent from the description of species and forms of embodiment,

and from the drawings. The invention is herematter explained with particular reference to bases of Edison and like screw and center or end contact types; but it will be understood that it is also applicable to bases of other and very different types, such as the double end-contact bayonet type, for example.

In the drawings, Fig. l is a partial and mainly sectional side view of a lamp based in accordance 'with the invention; Fig. 2 is a similar view illustrating a. modified construction; Fig. 3 is a similar view illustrating other modifications; and Fig. 4 is a perspective or tilted end view of the base structure shown in Fig. 3, with a portion broken out to show a radial section.

Fig. 5 is a partial sectional view of a lamp based according to the invention in a modified form, with apparatus for. casting a part of the base: and Fig. 6 is a perspective or tilted view of the base shown in Fig. 5, with a portion of the lamp bulb.

Figs. '7 and 8 are partly sectional side views of a lamp based according to the invention as shown in Figs. 5 and 6, with apparatus for casting another part of the base. I

Fig. 9 is a partial and mainly sectional side view of a lamp based according to the invention, in a further modified form.-

Fig. 1 shows an incandescent lamp L whose bulb 20 has a reduced neck portion 2| terminating in an end seal 22 formed by interiusion with envelope or bulb neck, these parts include a base the tubular stem flare 23, through whose seal 3 press 24 the current leads 25. 26 enter the bulb. An exhaust tube 21 opens through the press 24 and is sealed oil at its outer end 23, beyond the neck end 22. Adjacent the neck end 22 is a base insulator 30 of hollow conical configuration, shown as engaging or abutting against a corresponding conical outer surface 3| of the bulb neck, and adapted to be made of glass or other heat-resistant insulative material. The insulator 30 has a central opening 32 for the lamp lead 25, and a correspondingly apertured contact button 33 of ordinary sheet metal rivet type may be molded or spun into the insulation around this hole 32 as usual. The lead wire 25 extends out through the opening 32 and the contact 33, and is electrically connected to the latter by solderlng or welding, as indicated at 34.

Around the peripheries of the neck end 2| and of the insulator 30 is a thin metal band 35 which secures the parts together, being provided with shouldered engagement means for interlocking coaction with or behind corresponding shouldered engagement means of the bulb neck and of the insulator, and is shown as externally screwthreaded to serve as a screw contact. As here shown, the bulb neck shoulder 36 is formed by one side of an annular groove in the neck which accommodates a shoulder-forming inturned bevelled flange 31 at the upper edge of the band 35,?

while the outer margin or edge of the conical insulator 30 forms its shoulder, and isrreduced on a corresponding bevel at 38 to accommodate a shouldered inturned bevelled fiange 39 at the lower edge of the band 35. Any suitable means of antiturning engagement may be provided on the bulb neck 2| and on the band 35, such as external depressions 40 in the bulb neck into which look corresponding internal teeth on the band, or vice versa. As shown, the lamp lead 25 extends out between the conical bulb neck surface 3| and the corresponding internal surface of the insulator, either of which may be grooved to accommodate this wire, and its outer portion is electrically connected to the band or shell 35. As explained hereinafter, the band 35 may be die-cast around the parts 2|, 30 in the relations thereto above described, and the outer portion of the lead wire 26 may be embedded in the fused metal of the band when it solidifies, and thus connected thereto.

The construction illustrated in Fig. 2 is like that of Fig. 1 except that the end contact button 33a is cast into the lead hole 32 of the insulator 30a, whose end is reduced on a bevel at 4| to accommodate a bevelled annular flange on the button.

Fig. 3 shows a construction very similar to that in Figs. 1 and 2, but with a base insulator 30b having a wide-angled internal conical surface that abuts and fits snug against the usual rounded neck end adjacent its periphery at 3|. Also, the insulator shoulder 38b is formed b P ripheral reduction of the insulator, and the corresponding interlocking portion of the band 35 is a mere internal shoulder. The end contact button 33b is shown as cast into the lead hole 32 and around a shouldered protuberance 'ilb on the end of the insulator, and the lead hole 32 is considerably enlarged at 32.1: to allow for a head 331: east integral with the button 33b. The lead 25 is embedded in the cast metal of these

parts

33b, 33a.

Fig. 4 illustrates another modified form of base insulator 30c. specially suitable to be made of transparent material, like glass. It difiers in having an unreduced periphery, with a shoulder 380 formed by the flat top surfacepf its margin. As shown,-there is a radial groove 43 in the end of the central head Me to accommodate the outward bent lead 25, and there is a similar groove 44 across the periphery of the insulator'30c to accommodate the lead 26. As shown in Fig. 4. letters and figures indicating the voltage, and wattage, etc., of the lamp or other device may be marked on the inside surface cf'the insulator 300 so as to be read easily through it, while at the same time protected from defacement.

Fig. 5 illustrates the basing of a lamp and the concomitant casting of a band 35d according to the invention, certain modifications of the bulb neck and of the base insulator being also shown. At the left of Fig. 5, the mold cavity D for the band 35d is shown empty, while at the right it is shown filled with the cast metal. As regards the base insulator 30d, the modifications consist mainly in a rounded, dome-like configuration, in a high central protuberance or boss 4|d peripherally reducedto take a marginal flange of the cast-on button 33d and in an internal bevel 3|d at the upper edge of the insulator, with radial grooves 4411 to accommodate the lamp lead 25. As regards the bulb neck 2|d, the modification consists in a simpler configuration than in Figs. 1, 2, and 3. Fig. 6 shows the base as produced and attached according to Fig. 5, and shows letters and figures marked on the inside surface of a transparent insulator 30d, where they are protected from defacement, to indicate the voltage, and wattage of the lamp, etc. The convex configuration of the insulator 3011 results in apparent magnification of these letters and figures. Other letters indicative of the make of the lamp (or the like) are shown as cast into the center contact button 33d.

Fig. 5 illustrates the basing of a lamp according to the invention by die-casting a band 35d around the base insulator and the bulb neck. Thegeneral technique illustrated is of course applicable to other forms of construction besides that shown in Fig. 5. The center contact button 33d shown in Fig. 5 may be cast on to the insulator 30d as a separate operation, either before or after casting the band 35d.

For casting the band 35d, Fig. 5 shows a mold 50 associated with and surrounding the base insulator 30d and the bulb neck 2| d. This mold 50, which may be of iron or mild steelor other suitable metal, has a central end opening 5|, here shown at its bottom, and comprises a plurality of annular sections. These may consist of a lower part 52 having upper and lower internal annular shoulders 53, 54 to seat and center the insulator 30d, and an upper part 55 seated and centered around a reduced external annular shoulder 56 on the part 52 and extending up around the upper portion of the insulator 30d and around the bulb neck 2| d. To form the band 35d, the mold 50 affords a radially thin annular mold cavity D overlapping behind or above the shouldered dowelbosses 35d of the neck 2|d and also behind or below the rounded shoulder 33d of the domeshaped insulator 30d. As shown, this mold cavity D lies mainly or entirely in the upper mold section 55. To form external screw threads on the band 35d, there is a rounded helical groove 51 in the internal surface of the mold section 55. For the passage of molten metal from the bottom opening 5 where it is introduced, up into the annular cavity D, there and upward-sloping channels or grooves 53 are numerous outward across the annular shoulders ll, on which the base insulator 80d rests, giving this portion of the mold wall a fluted character, so that the molten metal can travel upward outside the in sulator, and even without coming in contact with it at all.. The molten metal may be introduced into the opening 5| by any suitable means, here indicated as upward-open conduit or spout 59 through which the metal may flow under suitable pressure.

When the apparatus is to be used, the mold 50 is heated by any suitable means (not shown) hot enough to obviate rapid chilling and solidification of molten metal as it strikes the mold wall. The

insulator 30d and the bulb d having been placed in the mold as shown, with the lead wire 28 extending out and up into the mold cavity D, and the lead extending down into the opening 32d, the parts are rapidly revolved together about an upright axis coincident with their own axes, and a sufficient charge of molten metal is forced through the conduit 59 and discharges therefrom into the moldlopening 5|, amongst the metal ridges or flutes" 'which define and separate the grooves 58. With the mold 50 revolving at adequate speed, the centrifugal force lifts the metal along the sloping grooves 58 and distributes it unformly throughout the mold cavity D, completely filling the latter to form the band d, and securing the

parts

20d and 30d together... As soon as the metal cools and solidifies in the mold which may be hastened by blowing jets of air or other cooling fluid.(not shown) against the exterior of the mold-the completed assembly of parts can be removed and replaced with another insulator 30d and bulb 20d, and the casting operation can be repeated.

As illustrated in Figs. 7 and 8, the casting of the contact button 33d may be done in a separate stationary open-top mold 60 into which molten metal is introduced under pressure through 9. lateral conduit or spout 6| delivering into said mold when the latter is lowered away from the insulator 30d as shown in Fig. '1. The mold 80 is then raised against and around the insulator boss Md, so that the molten metal in the mold rises into the insulator lead hole 32d and its enlargement 323:, Fig. 5. During these operations, the lamp L may be held as shown, with the reduced lower portion of its insulator 30d engaged in a bevelled opening in a supporter 62, .and with an aligning cup-like top holder 63 bearing on the upper end of the bulb 2Id. Thus an enlarged head is formed in the insulator 30:1 to secure the button 33d to the latter, and the outer portion of the lead wire 25 is embedded in this head and in the button. The mold 80 fits and seals around the conical insulator 30d when the mold comes up against the insulator. The mold 60 may in use be heated suiliciently to avoid premature solidification of the molten metal.

Any metal (or alloy) suitable for die-casting can be used to cast the parts 33d. 35d as above described, provided its melting point is not so high as to soften or injure the materials of the bulb neck Md and of the insulator. Type metal is very suitable for use with the ordinary soft glass of incandescent lamp bulbs.

Fig. 9'lllustrates a modification in which the base is applied to a skirt extension 2la: of the bulb neck 2| that projects beyond the stem flare or mount seal 22, this seal being a substantial distance behind the extreme end of the neck or skirt. Thus it is the skirt 2k: that carries the shouldered bosses or dowels llefwhich are shown solid. rather than as hollow embossments as in Fig. 5. The lower inner corner of the skirt 2k: is shown rounded away at 3 la, and the upper edge of the dome-like base insulator tile is bevelled outward at 38c, instead of inward as in Fig. 5. The material to form the skirt 2lx may be provided in sealing the mount into the bulb, by retaining a short cullet" portion of the bulb neck integral with the seal at 22, instead of fusing it of! as usual.

In Figs. 2-9, various parts and features are marked with the same reference characters as are applied to corresponding ones in Fig. 1, in order to dispense with repetitive description-a distinctive letter being added where such distinction appears necessary.

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

l. The combination with an electric lamp having a bulb with a hermetically sealed and externally shouldered neck end presenting antiturning engagement means, and a shouldered base insulator at said neck end of said bulb carrying a center contact button, of a cast metal screw shell contact around theperipheries of said neck end and said insulator interlocked behind their shoulders, whereby said parts are secured to one another, and also antiturningly engaged with said antiturning engagement means of said neck end, a lamp lead extending out through said centercontact button and electrically connected thereto, and a lamp lead extending out between said neck end and said base insulator to said screw shell, and electrically connected to the latter.

2. The combination with a bulb having a neck with dowel means distributed therearound, and a base insulator also having shouldered engagement means therearound and carrying center contact means, of a cast metal screw shell contact around said neck and said base insulator and interlocked with their dowel and engagement means aforesaid, whereby said parts are secured together and turning'of said screw shell relative to said bulb is prevented.

3. The combination of an electricjamp having a bulb with a shouldered neck, a shouldered base insulator at the neck end of said bulb having an end-contact lead opening, with leads from said lamp severally extending out through said endcontact lead opening and out between said bulb neck and said base insulator, and a cast metal contact band around said neck and said base insulator and locked behind their shoulders, and having an outer portion of the last-mentioned lamp lead embedded therein.

4. The combination of an electric lamp having a bulb with a hermetically sealed and externally shouldered neck and presenting antiturning engagement means, a shouldered base insulator abutting against said neck end and having an end-contact lead opening, with leads from said lamp severally extending out through said endcontact lead opening and out between said bulb neck end and said base insulator, and a cast metal screw shell contact around said neck and said base insulator and locked behind their shoulders and with said antiturning engagement means, and having an outer portion of the last-men-l tioned lamp lead embedded therein.

5. The combination of an electric lamp having a bulb with a shouldered neck, a shouldered base insulator at the neck end of said bulb having an end-contact opening, with leads from said lamp severally extending out through said opening and out between said neck and said base insulator, a cast metal contact band around said neck and base insulator and locked behind their shoulders, with an outer portion of the last-mentioned lamp lead embedded therein, and a cast metal endcontact in the aforesaid opening of said insulator, with an outer portion of the first-mentioned lead embedded therein.

6. The combination of an electric lamp having a bulb with a neck having dowel means distributed therearound, and a base insulator at the neck end of said bulb having an end-contact opening and also having shouldered engagement means therearound, with leads from said lamp severally extending out through said opening and out between said neck and said base insulator, a cast metal screw shell contact around said neck and said base insulator and interlocked with their dowel and engagement means aforesaid, with an outer portion of the last-mentioned lamp lead embedded therein, and a cast metal end-contact in the aforesaid opening of said insulator, with an outer portion of the first-mentioned lead embedded therein.

7. A method of basing a lamp having a shouldered neck which comprises placing the lamp and a shouldered base insulator at the end of said neck in a mold surrounding said parts with an annular mold cavity overlapping behind their shoulders, and introducing molten metal into said annular mold cavity to fill the same while rotating said mold, lamp, and base insulator at sufficient speed to centrifugally distribute the molten metal throughout said cavity, continuing rotation of the parts until the metal solidifies.

8. A method of basing a lamp having a shouldered neck which comprises placingthe lamp and a shouldered base insulator at the end of said neck in a mold surrounding said parts with an annular mold cavity overlapping behind their shoulders and having a central opening at the end of the insulator, with passage therefrom outward to said annular mold cavity, and introducing molten metal into said opening to fill said cavity while rotating said mold, lamp, and base insulator at sufflcient speed to centrifugally distribute the molten aforesaid and throughout said cavity, continuing rotation of the parts until the metal solidifies.

9. A method of basing a lamp having a shoul- I dered neck which comprises placing the lamp and a shouldered base insulator at the end of said neck upright in an upwardopen mold seating and sustaining said insulator below its shoulder and surrounding adjacent portions of the said lamp neck and insulator with an annular mold cavity overlapping above and below their respective shoulders, and also having a central opening be neath said insulator with passage therefrom upward and outward to said and introducing molten metal into said opening to fill said cavity while rotating said mold, lamp, and base insulator at sufficient speed to centrifugally distribute the molten metal through the passage aforesaid and througout said cavity, continuing rotation of the parts until the metal solidifies.

10. Apparatus for basing a lamp having a shouldered neck with a shouldered base insulator at the end of said neck, said apparatus comprising a mold for surrounding adjacent portions of said neck and insulator with an annular mold cavity at its upper end overlapping behind the" shoulders of said lamp-neck and insulator and annular mold cavity,

lamp, and base metal through the passage l shoulder, and also having a central opening at its lower end opposite the end of the insulator, with passages inclined outwardly and upwardly therefrom to said annular mold cavity, means for introducing molten metal into said opening to fill said cavity, and means for rotating said mold,

about their vertical axes to centrifugally pass the molten metal upward through said passages and distribute the same throughout said cavity.

11. In an electrical device of the class described comprising a sealed glass bulb havin a neck portion, a base comprising an insulator body covering and engaging the end of said bulb neck and secured thereto by a cast metal shell circumposed directly on and spanning adjacent portions of said bulb neck and insulator body, said metal shell being cast in place around said bulb neck and insulator and being shaped to engage in a socket.

12. In an electrical device of comprising a sealed tion with lead wires extending therefrom, a base comprising an insulator body carryin a contact member and covering and engaging the end of said bulb neck and secured thereto by a cast metal shell circumposed directly on and spanning adjacent portions of said bulb neck and insulator body, said metal shell being cast in place around said bulb neck and insulator and being shaped to engage in a socket, one of tending to and being electrically connected with said shell, and another lead wire extending to and being electrically connected with said contact member on said insulator body.

13. In an electrical device of the class described comprising a sealed glass bulb having a neck portion, a base comprising an insulator body covering and engaging the end of said bulb neck and secured thereto by a cast metal shell circumposed directly on and spanning adjacent portions of said bulb neck and insulator body, said metal shell being cast in place around said bulb neck the class described and insulator and being shaped to engage in a shell circumposed directly on and spanning adjacent portions of said bulb neck and insulator body, said metal shell being cast in place around said bulb neck and insulator and being shaped to engage in a socket, the portions of said bulb neck and insulator body circumposed by said shell being configurated to provide interlocking engagement of the shell therewith against separation or rotation of said insulator body relative to said bulb neck, one of said lead wires extending to and being electrically connected with said shell, and another lead wire extending to and being electrically connected with said contact member on said insulator body. 7

15. In an electrical device of theclass described comprising a sealed glass bulb having a neck portion with lead wires extending therefrom. a base comprising an insulator body carrying a contact glass bulb having a neck porsaid lead wires examam member and covering and engaging the end of said bulb neck and secured thereto by a cast metal shell circumposed directly on and spanning adjacent portions of said bulb neck and insulator body, said metal shell being cast in place around said bulb neck and insulator and bein shaped to engage in a socket, one of said lead wires extending to and being embedded at its end in said shell, and another lead wire extending to and being electrically connected with said contact member on said insulator body.

16. The method of basing a glass electric lamp bulb having a neck portion which comprises placing a base insulator against said neck portion, surrounding said neck portion and insulator with a mold having a cavity overlapping adjacent portions of said neck portion and insulator, introducing molten metal into said cavity to fill it while rotating said mold, bulb and insulator at sufllcient speed to centrifugally distribute the molten metal throughout said cavity, and continuing rotation of said parts until the metal solidifies.

ELMER B. ISAAC. FRANCIS J. RIPPL.

RWERENCES CITE UNITED STATES PATENTS Number Name Date 2,257,475 Metz Sept. 30, 1941 2,256,062 Taylor Sept. 16, 1941 2,290,073 Said July 14, 1942 645,266 Kremenezky Mar, 13, 1900 653,038 Piechati July 3, 1900 1,806,787 Conradty May 26, 1931 2,275,503 Brown Mar. 10, 1942 2,149,702 Maris Mar. 7, 1939 1,650,289 McGinley Nov. 22, 1927 1,556,342 Peth Oct. 6, 1925 2,159,812 Malloy May 23, 1939 1,965,231 Gustin July 3, 1934