US2349349A - Incandescent electric lamp - Google Patents

Description

May 23, 1944. A. M. HAGEMAN 2,349,349

INCANDES CENT ELECTRIC LAMP Filed July 2, 1942 INVENTOR BY Awrm ATTORNEY Patented May 23, 1944 INCANDESCENT ELECTRIC LAMP Aaron Martin Hageman, Verona, N. 1., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 2, 1942, Serial No. 449,443

14 Claims.

This invention relates to incandescent electric lamps and, more particularly, to such eliminating the usual metal base.

The principle object of my invention, generally considered, is to produce an incandescent electric lamp having a molded glass base forming part of the bulb, and with leads therethrough functioning as contacts to the socket.

Another object of my invention is the provision of an incandescent electric lamp having a screw threaded' glass base forming part of the bulb and through which the leads pass, at least one of said leads being hollow to function as an exhaust tube.

A further object of my invention is the provision of an incandescent electric lamp in which the press portion is in the base, whereby it is far removed from the incandescible filament, making it possible to decrease the size of the bulb.

A still further object of my invention is the provision of an incandescent electric lamp in which the base is of glass with the edge sealed to the adjacent portion of the bulb, and hollow or rigid leads extending through said glass base and directly receive the metal filament supports, whereby the base performs the additional function of a flare and press.

Other objects and advantages of my invention, relating to the particular arrangement and construction of the various parts, will become apparent as the description proceeds.

Referring to the drawing:

Fig. 1 is-an axial sectional view of an incandescent electric lamp embodying my invention.

Fig. 2 is a fragmentary elevational view of the base and adjacent bulb portion of said lamp, on the line 11-11 of Fig. 1, in the direction of the arrows.

Fig. 3 is an enlarged transverse sectional view on the line IIIIII of Fig. 1, in the direction of the arrows.

Fig. 4 is an axial sectional view of the base of the lamp, prior to connection with the bulb and lead-in conductors.

Fig. 5 is an axial sectional view of the center beaded lead-in conductor prior to connection with the base.

Fig. 6 is an axial sectional view of the other beaded lead-in conductor prior to connection with the base.

Fig. 7 is an axial sectional view corresponding to Fig. 4, but showing a slightly modified lamp base and the second-mentioned lead-in conductor in the process of being connected to the base.

Fig. 8 is an elevational view of the mount or filament and supporting wires, separated from the rest of the lamp.

Fig. 9 is a view corresponding to Fig. 4, but showing both of the lead-in conductors in place in the base, and the filament support wires prior to connection with said conductors.

Fig. 10 is an axial sectional view of the base and a portion of the bulb, during the process of connecting said parts prior to the exhausting and filling operation.

Fig. 11 is an elevational view of the base and lower portion of the bulb of a lamp which has been exhausted and is being tipped-off by fiattening and welding the center lead-in conductor which functions as an exhaust tube.

Fig. 12 is a View corresponding to Fig. 10, but showing a modification.

Referring to the drawing in detail, and first considering the embodiment of my invention shown in' Figs. 1 to 11, inclusive, there is shown a lamp l2 comprising a bulb portion H! which may be formed conventionally of Nonex (or lead borosilicate, Corning Code #772) glass, although my invention makes it possible to use a somewhat smaller bulb, and soft or other than Nonex glass may be used. The present embodiment of my invention is that of a watt, volt lamp, interchangeable with the standard lamp, although I am not limited to such showing. The bulb is secured to a base H! which is pre-formed of glass adapted to seal directly thereto. The pre-formed base It is shown separated from the bulb in Fig. 4 and desirably formed of the same kind of glass as that of the bulb. The base is shown screw-threaded, as indi cated at 20, although this is not essential, as my invention may be embodied in an automobile lamp or other type without a threaded base. It initially has a central aperture l5 through a boss it to receive the combined center contact and lead-in conductor. A hole l1, through the shoulder at the side of the said aperture I5, is provided for the other or side combined contact and leadin conductor.

In order to provide for supplying power to the filament a pair of lead-in conductors l8 and I9 are provided, as respectively illustrated in Figs. 5 and 6. Both are desirably initially hollow metal members or tubes of small size and bore. The purpose of using small tubing in the present instance, rather than solid conductors, is to provide, with the same amount of metal, supports which are more rigid and to which the lamp leads may be conveniently attached, to avoid absolute matching of the'tubing metal expansion and the glass expansion, and to provide means for exhausting the lamp without a separate exhaust tube.

1! hard glass such as Nonex" (Corning code #772 or lead borosilicate glass) is used, the leads may be formed of "Kovar" (which is a patented Co.-Ni.-Fe. alloy) or nickel iron alloy, while if soft glass is substituted copper or chrome iron tubing is desirably employed. Leads l8 and I! are beaded, as indicated at 2| and 22, with material which will seal thereto without cracking and which will also satisfactorily seal to the glass of the base ll. Ii "Kovar tubing is employed the beading material may be #704 (soft borosilicate) or other glass which has the proper coefilcient of expansion for the purpose. If copper tubing is employed as when using the soft glass bulb and base, then correspondingly soft glass beads are substituted.

The all glass base is illustrated in Fig. 4 as having the shape and dimensions of a standard metal base, that is, provided with raised portions around its outer curved surface forming screw threads. A small break or groove 23 is provided from top to bottom of the base, forming a channel to receive the outer portion of the side lead tubing 19, after being flattened and bent as shown most clearly in Figs. 1, 2, 3, and 11. In the specific embodiment shown, thin-walled "Kovar tubing approximately .080 inch in diameter may be used for the leads l8 and I9, each of which may be initially 40 millimeters long. One piece, that is the one designated II for the center contact, is provided with a side aperture 24 for exhausting the bulb, and the other piece I8 is welded shut, as

at 25 just above the bead 22, in order to insure a vacuum-tight lead.

The glass base Il may first be heated slowly until it reaches a temperature Just below the softening point. While at this temperature, the beaded Kovar" side lead I! may be introduced into the aperture ll, as indicated in Fig. 7, which also shows the base l4 slightly modified as compared with that of Fig. 4, by having its edge sharper to facilitate connection with the bulb I3, and sealed tightly, as by means of fires 26, the end of the tubing having the weld 25 projecting inside of the base, as shown in Fig. 7. The center contact 18 having the bead 2| may be similarly sealed-in the center opening l5, leaving the part carrying the small hole 24 projecting inside the base. The base with the leads sealed therethrough, as shown in Fig. 9, is then desirably annealed and allowed to cool slowly.

The next step is the attaching of the filament unit to the Kovar" leads. This unit may be a standard coiled-coil tungsten wire 21 supported by nickel wires 28 and 29, the central one 28 of which has a portion 30 offset in order that it may be spaced from the axis like the wire 28, to center the filament 21. The inner ends of said wires 28 and 28 are turned towards one another and connected by a bead 3| of Nonex or other suitable glass. The ends of the filament 21 may be supported by molybdenum lead extensions 32 and 33, the inner ends of which are clamped over the filament ends and the outer portions of which are welded to the nickel wires 28 and 29, respectively. A center filament support 34, which may also be formed of molybdenum, is coiled around the filament as indicated at 35 and has its other end embedded in the bead 3|. This filament unit is desirably attached to the base by placing the lower or outer end portions of the nickel wires 28 and 29 in the inner ends of the Kovar" tubing.

as shown most clearly in Figs. 9 and 10, and welding or crimping in place. The side tube is carefully flattened to form a thin bar, bent upwards, and put in the groove 23 of the base, while slightly spaced from the bottom 01' said groove when the base is out of its socket, so as to form a "spring contact.

The neck of the standard "Nunez" bulb [I may then be drawn down to the diameter of the base I, cut-off so as to have the desired over-all length, in this instance millimeters, and sealed to the base as by means of fires 38, as indicated in Fig. 10. The lamp may be exhausted through the lead l8, as shown in Fig. 10, and filled in accordance with standard practice. It may then be sealed off, while on the exhaust machine 31, by welding the Kovar" lead l8 close to the base, using electrodes 38 and 39 as shown most clearly in Fig. 11, thereby completing the lamp which may be used like a standard screw threaded incandescent electric lamp.

Referring now to the embodiment of my invention illustrated in Fig. 12, there is shown a construction in which the bulb portion 13 has a neck portion 14* formed with screw threads 20'', as illustrated, in order that it may function as the usual brass base 01' a commercial incandescent electric lamp. The bottom of the base portion, however, designated by the reference character 4 I, is formed as a glass disk through which passes a hollow center lead member l8 and a side or other hollow lead member l9". These lead members lB and 19 may be formed as shown, respectively, in Figs. 6 and 5, that is the lead l8 may be formed to correspond with the lead l8 and the lead I! may be formed to correspond with the lead l8. That is, the lead I8 is welded or otherwise sealed as indicated at 25" to make it gastight. Likewise, the lead l9 is desirably provided with a relatively small hole 24" in its side so that it may be used for exhausting purposes.

The leads 18 and I! may be beaded like the leads l9 and 18, as indicated in Fig. 5 and then sealed through the disk ll apertured like the bottom of the glass base I or H, as shown most clearly in Fig. 7. As an alternative, however, the glass of the disk 4| may be actually molded about the leads l8 and I9 to make the assembly illustrated in Fig. 12, in a manner such as described and claimed in the Richardson application, Serial No. 362,530, filed October 24, 1940, and owned by the assignee of the present application. The material of the tubing I8" and 18 may correspond with that of the first embodiment.

The threaded portion ll of the bulb I3 is likewise provided with a small break or groove 23 to receive the outer portion of the side lead tubing l9 after being flattened and bent as shown in Fig. 10, this of course occurring after the operation of the exhausting and sealing of said tube.

The glass disk portion ll, either formed with the leads I8 and l9 in place, or after the same have been sealed therethrough as in the first embodiment, is assembled with a filament unit which may be like that illustrated in Fig. 8. It is attached to the hollow leads l8 and I9", desirably as by placing the lower or outer end portions of the nickel wires 28 and 29 in the inner ends of the Kovar" or other tubing l8 and I9", as illustrated, and welding them in place. The outer end of the lead l8 is flattened or at least partially closed as, indicated at 42, to function as the center contact. The disk ll is sealed to the lower or outer end of the threaded portion ll", as by means of fires 38 to thereby complete the lamp except for exhausting and sealing of the exhaust tube, said lamp being, except for the leads, approximately like that shown in Fig. 11.

. The lamp is then placed as shown in said Fig. 12, exhausted and filled, in accordance with standard practice, through the lead l9". It may then be sealed off while on the exhaust machine 31' by welding or otherwise closing the lead It, close to the base, using electrodes or other closing means, such as those designated 38 and 39 in Fig. 11. The portion or the tube beyond the weld is then carefully-flattened to form a thin bar, bent upwards and put in the groove 23 of the base, while desirably slightly spaced from the bottom of said groove when the base is out of its socket, so as to form a "spring contact, as in the first embodiment.

It will also be understood that although I have described the incorporation of the leads in the base of the first embodiment in a special way, that is by first beading and then connecting in apertures, yet if desired said leads may be incorporated with the base by supporting in a base mold and pressing glass therearound, like the formation of the glass articles with hollow leads molded in place, as described and claimed in the Richardson application previously referred to. It will also be understood that in both embodiments, whether molded in place or not, the leads or one of them may, if desired, be solid rather than hollow, although at present it seems preferable to form them hollow for the reasons pointed out.

It will also be understood that the purpose of using thin walled hollow leads, or metal tubing, passing through a relatively heavy glass base and serving as supports for the telescoping lead wires inside the lamp, is in order to have plenty of rigidity to support said leads and filament assembly on the inside of the lamp, while at the same time conserving metal by the use of very thin walls and making it unnecessary that the metal and glass have the same coefiicient of expansion, as said very thin tubing will be able to expand and contract with the glass without as much danger of the latter cracking. It is also easier to form the side contact, 01 the desired relatively fiat shape, from tubing than from solid wire.

If the lead wires or tubing are fixed in the glass base or disk while the latter is formed or molded thereabout, it is believed to be desirable to preheat them to at least the temperature or higher than that, oi the glass, if the same is pressed thereabout rather than being very fluid and allowed to fiow therearound. In other words if the temperature of the glass when it strikes the mold is about 800 C., a tight union between the lead wires and glass will result if the lead wires are preheated to that temperature or slightly above, whereby the heat capacity of the metal does not cause chilling of the surface of the glass coming in contact therewith.

From the foregoing disclosure, it will be seen that I have invented an incandescent filament electric lamp with an all-glass base, showing that the same is perfectly practicable, whereby a considerable saving of time and metal is accomplished, and involving a radical departure from the present commercial lamps.

Although in the preferred embodiment I have suggested the use of Kovar and hard glass as the material for the leads and base, respectively, it will be understood that I contemplate copper and soft glass, and that instead of tubing I may, if desired, use such for only the center contact, in

order to allow it to perform the additional function of an exhaust tube. As a further alternative, I may use solid conductors for both of said leads. with a supplemental glass or other exhaust tube.

An additional advantage in the use of my invention is that on account of having the base forming, in effect, an extension on the bulb, it is adapted to catch some of the blackening and thereby to that extent reduce the deterioration of the lamp efllciency. Saving in materials and processing operations results from the elimination of the operation of attaching a metal base to a glass bulb, elimination of the lamp press and flare, the feasibility of using smaller bulbs, and

the elimination of brass or other metal for the base.

Although preferred embodiments of my invention have been disclosed, it will be understood that other modifications may be made within the spirit and scope of the appended claims.

I claim:

1. An incandescent electric lamp comprising a bulb terminating in a threaded neck portion adapted to lit a standard lamp socket, a glass disk closing the outer end of said threaded neck portion, leads passing through said disk, the outer ends of said leads functioning directly as socket contacts, mount support wires extending from the inner ends of said leads, and a filament supported by said wires.

2. The method of making an incandescent electric lamp comprising forming a glass base with a central aperture and one disposed to the side thereof, sealing lead-in conductors through said apertures, supporting a filament on the inner ends of said lead-in conductors, bending the side lead-in conductor against the base side so as to function as a contact, sealing a bulb to the edge of said base, exhausting, and cutting short the external portion of the center lead to function as a center contact.

3. The method of making an incandescent electric lamp comprising forming a glass base with a central aperture and one disposed to the side thereof, sealing tubular lead-in conductors throu h said apertures, fittin filament support wires to the inner ends of said lead-in conductors, flattening and bending the side lead-in conductor against the base side so as to function as a contact, sealing a bulb to the edge of said base, exhausting through the center lead-in conductor, and cutting short the external portion of the center lead to function as a center contact.

4. The method of making an incandescent electric lamp comprising forming a bulb with a neck portion threaded so that it will fit a standard socket, forming a glass disk for closing said threaded neck portion, said disk being provided with a center aperture and one disposed to the side thereof, sealing lead-in conductors through said apertures, supporting a filament on the inner ends of said lead-in conductors, sealing the edge of said disk to the outer edge of said threaded neck portion, cutting short the external portion of the center lead to function as a center contact, exhausting through, sealing, and bending the side lead-in conductor against the neck so as to function as a side contact.

5. The method of making an incandescent electric lamp comprising forming a bulb with a neck portion threaded so that it will fit a standard socket, forming a glass disk with center and side lead-in conductors molded in place for closing said threaded neck portion, supporting a filament on the inner ends of said lead-in conductors,

sealing the edge of said disk to the outer edge 0! said threaded neck portion, cutting short the external portion of the center lead to function as a center contact, exhausting, sealing, and bending the side lead-in conductor against the neck so as to function as a side contact.

6. The method of making an incandescent electric lamp comprising forming a glass base with central and side apertures, sealing lead-in conductors through said apertures, supporting a. filament on the inner ends of said lead-in conductors, sealing a bulb to the edge of said base, and

exhausting said bulb through said base.

'7. The method of making an incandescent electric lamp comprising forming a bulb with a neck portion threaded to engage a socket, forming a glass disk for closing said neck portion, said disk being provided with center and side apertures, sealing lead-in conductors through said apertures, supporting a filament mount on the inner ends of said conductors, sealing the edge of said disk to the outer edge of said threaded neck portion, and exhausting through and sealing one of said lead-in conductors.

8. The method of making an incandescent electric lamp comprising forming a bulb with the neck portion threaded so that it will fit a socket. forming a glass disk with center and side lead-in conductors molded in place, closing said neck portion by means of said disk, supporting a filament mount on the inner ends 0! said lead-in conductors, and exhausting and sealing said bulb.

9. An incandescent electric lamp provided with a glass base and leads extending through said base and with outer end portions forming contacts for directly engaging a socket, one of said end portions being positioned to engage the center contact of said socket and the other being bent along the side of said base to resiliently engage the side of said socket.

10. An incandescent electric damp provided with a glass screw-threaded base for connection to a socket of standard size, said base having a longitudinal slot intersecting the threads thereof, and leads extending through said base, the outer end of one of said leads being positioned to engage the center contact of an associated socket and the other lead being disposed in said slot as a side contact.

11. An incandescent electric lamp provided with a glass screw-threaded base for connection to a socket of standard size, said base having a longitudinal slot intersecting the threads thereof, and tubular leads extending through said base, the outer end 01' one of said leads being positioned to engage the center contact of an associated socket and the other lead being flattened and disposed in said slot as a resilient side contact.

12. An incandescent electric lamp provided with a glass base and leads extending therethrough, at least one of said leads being hollow, a filament support wire telescoping with the inner end portion of said hollow lead, and a side exhaust aperture provided therein between the outer end of said support wire and the inner surface of said base.

13. An incandescent electric lamp comprising a glass bulb having an outer neck portion provided with screw threads, a generally flat allglass disk, the plane of which is generally perpendicular to the axis of said neck portion, leadin conductors carried by said disk and of such rigidity that their outer end portions can function directly as socket contacts, said disk having its peripheral edge sealed to the free edge of the threaded neck portion of said bulb in order to complete the lamp, the inner ends of said conductors carrying a mount comprising supports carrying an incandescible filament.

14. An incandescent electric lamp comprising a bulb, a glass base formed as a threaded cylindrical portion adapted to fit a standard lamp socket and a glass disk closing the outer end thereof, stifl leads passing through said disk, the outer ends of said leads functioning directly as socket contacts, mount support wires extending from the inner ends of said leads, a filament supported by said wires, and the lamp bulb being completed by a uniting of the free edge of said cylindrical threaded portion to the free edge of the bulb neck.

AARON MARTIN HAGEMAN.

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