US3007073A - Electric lamp mount - Google Patents

Description

Oct. 31, 1961 S. E. SWASEY ETAL ELECTRIC LAMP MOUNT Filed Aug. 27, 1959 KENTON R. BAGLEY SAMUEL E. PWASEY lNV NTORS BY I C W & ATTORNE Unite fitate 3,007,073 ELECTRIC LAMP MOUNT Samuel E. Swasey, Edgemere, and Kenton R. Eagley, Beverly, Mass, assignors to Sylvania Electric Products Inc., a corporation of Delaware Filed Aug. 27, 1959, Ser. No. 8.363% 2 Claims. (Cl. 313-277) This invention relates to the manufacture of electric lamps and more particularly to the manufacture of incandescent electric lamps.

Over the years, many different types, shapes, sizes, etc. of incandescent lamps have been made available commercially. Two of the basic components of many of these lamps are a mount and an envelope, the former being hermetically sealed within the latter to define an unbased lamp. Mount structures differ appreciably from one another depending on the particular type of lamp being made. Basically, the mount structure is an arrangement of electrical conductors, usually called leadin wires, and support wires for supporting the lamp filament inposi-tion within the hermetically sealed lamp envelope. This arrangement of Wires must be rugged enough and flexible enough to provide the necessary support for the filament over a broad range of environmen tal installation and operational conditions as well as during transportation from the manufacturer to the ultimate user. On the other hand, it is most desirable, economically, that the mount structure be as simple as possible and readily lend itself to fabrication on automatic lamp manufacturing equipment. In addition to the foregoing, the attainment of these objectives, of course, should not be accomplished at the expense of light output, light distribution and other lamp performance characteristics.

This invention relates to a mount structure for incandescent lamps in which the filament is disposed vertically within the lamp envelope, i.e., the axis of the filament is substantially coincident with the longitudinal axis of the lamp envelope.

Therefore, an object of this invention is to provide a mount structure for vertical filament incandescent lamps in which the foregoing desiderata are attained.

In the specific embodiment of the invention illustrated in the accompanying drawing,

FIGURE 1 is an elevational view of an incandescent lamp with the mount structure therein shown in side elevation.

FIGURE 2 is an end elevational view of the mount structure of FIGURE 1.

Referring now to FIGURE 1, the lamp illustrated therein comprises a glass envelope 2 in one end of which a glass stem 4 is hermetically sealed. The stem 4 is provided with a stem press 6, Within which lead-in Wires 8 and 10 are sealed. The lower portions of the lead-in wires 8 and 10, depending from the stem press 6, are connected in the usual manner to a base 12, with which the lamp envelope 2 is provided. The upper portions of lead-in Wires 8 and 10 are provided with offset portions 8a and 16a respectively, to which the ends of a filament 14 are attached. One end of a filament support wire 16 is embedded in the stem press 6, the other end thereof being provided with a loop portion 17 which encircles the filament 14 intermediate the ends thereof to help retain the filament in position.

As is shown in FIGURE 1, the lead-in wires 8 and Ill diverge at their points of emergence from the stem press. The shorter lead-in wire 10 thus extends angularly for a short distance and then substantially parallel to the longitudinal axis of the lamp envelope, these segments being identified as 1012 and lfic in FIGURE 1, and finally terminates in an offset portion ltla to which one end of filament 14 is attached. The longer lead-in wire 8 extends 3,liil7,fi73 Patented Oct. El, 1961 angularly for a short distance and then substantially parallel to the longitudinal axis of the lamp envelops for a short distance, these segments of the lead-in wire being identified as 8b and 8c respectively in FIGURE 2. The leadin wire 8 is then bent angularly to the right and then to the left, as viewed in FIGURE 2, to define segments 8d and tie respectively, finally terminating in the aforementioned otfset portion 8a.

In the development of the above-described mount structure, it was found that the provision of angular bends to provide various segments of various lengths of the two lead-in wires contributed substantially to the attainment of the desired flexibility of the mount structure. In addition thereto, the segments 8d and 8c of the longer lead-in wire 8 are disposed so as to effect a substantial reduction in lead-in wire shadow.

One of the more critical problems associated with the development of a high quality mount structure for a lamp of this type was the integration of rigidity, flexibility and elasticity characteristics. With an axial filament, one lead-in wire is relatively short and the other lead-in wire is relatively long. In the manufacture of incandescent lamps, that portion of a lead-in Wire which is disposed within the stern press is usually of dumet and the exposed portion thereof within the lamp envelope is usually of nickel-plated copper. In using these conventional materials for the lead-in wires in an axial filament lamp, we found that the heat to which the lead-in wires were exposed during stem manufacture caused a softening of the lead-in wires and a loss in stiifness and elasticity. During shock tests, in some cases, it was. found that the leadin Wires flexed an unequal amount and tended to return toward the initial position an unequal amount. This, of course, meant that the mount structure was permanently deformed and distorted with resultant damage to or breakage of the filament. This undesirable condition Was due in large part to the fact that the exposed portions of the lead-in wires within the lamp envelope differed greatly in length. Because of the greater mass and leverage, the longer lead-in Wire flexed more and had much less tendency to return to its initial position than the shorter lead-in wire. In other cases, it was found that the lead-in wires were not flexible enough, the filament took the brunt of the shock, and in some instances the filament was broken as a result thereof.

We have found that these undesirable conditions may be overcome by making the longer lead-in wire, disposed Within the lamp envelope, of two different materials, a segment thereof nearer the stem press being of relatively stiff material and the upper portion thereof being of more flexible material. In the specific embodiment of the invention, a 100 watt lamp in an A-l9 bulb is disclosed. In this example, the exposed portion of lead-in wire 10 within the lamp envelope is .018 inch diameter nickelplated copper. The segment 81) and the beginning of segment of lead-in wire 8 are .016 inch diameter dumet, whereas the major portion of segment 80 and segments 8d, 86 and 8a are .016 inch diameter nickelplated copper. It is preferable that the dumet be joined to the nickel-plated copper above the bend, such as at 9;

in FIGURE 2 for example.

Although lead-iu wires of the foregoing specific materials having the foregoing specific dimensions have been found to be particularly satisfactory in the manufacture of a watt lamp in an Al9 bulb, it will be readily appreciated by those skilled in the art that lead-in wires of other materials having other specific dimensions may be employed without departing from the spirit and scope of the invention. In accordance with the principles of the invention, the upper segments of the longer lead-in wire, i.e., the major portion of segment 80 and segments 3d. 8e and 8a, should have substantially the same flexibility and elasticity as the short lead-in wire, particularly segments 10a and 100 thereof, whereas the lower segments of the longer lead-in wire, i.e., segment 8b, should be stiller or more rigid. It will be noted that in the specific example above, the upper segments of the longer lead-in Wire are of .016 inch diameter nickel-plated copper. This slight dimensional diflerence was found to be desirable in order to compensate for the greater efiect of the heat during stem manufacturing on the shorter leadin wire which is, of course, nearer the stem press 6 than the upper segments of the longer lead-in wire.

What we claim is:

1. A mount structure disposed within an electric lamp envelope having a longitudinal axis, said mount structure comprising: a filament, the longitudinal axis of which is substantially coincident with the longitudinal axis of said envelope; a stem press; and a pair of lead-in wires of unequal length anchored in said stem press and extending generally longitudinally Within said envelope and along opposite sides of the longitudinal axis of said envelope, each of said lead-in wires terminating in an inwardly extending segment to which the ends of said filament are attached, a segment of the longer lead-in wire adjoining the stem press being relatively stiff and the remainder of said longer lead-in wire and the shorter leadin wire being substantially more flexible than said segment of said longer lead-in wire adjoining the stem press, the said remainder of said longer lead-in Wire and the said shorter lead-in wire having substantally tihe same elasticity.

2. A mount structure disposed within an electric lamp envelope having a longitudinal axis, said mount structure comprising: a filament, the longitudinal axis of which is substantially coincident with the longitudinal axis of said envelope; a stem press; a pair of lead-in wires of unequal length anchored in said stem press and extending generally longitudinally within said envelope and along opposite sides of the longitudinal axis of said envelope, each of said lead-in wires terminating in an inwardly extending segment to which the ends of said filament are attached, a segment of the longer lead-in wire adjoining the stem press being relatively stifit' and the remainder of said longer lead-in wire and the shorter lead-in wire being substantially more flexible than said segment of said longer lead-in wire adjoining the stem press, the said remainder of said longer lead-in wire and the said shorter lead-in wire having substantially the same elasticity; and a filament support wire extending general-1y longitudinally Within said envelope, one end of said filament support wire being embedded in said stem press and the other end of said filament support wire being provided with a loop portion substantially encircling said filament intermediate the ends thereof.

References Cited in the file of this patent UNITED STATES PATENTS 706,313 Gilmore Aug. 5, 1902 951,232 Bresler Mar. 8, 1910 1,635,999 Housekeeper July 19, 1927 2,226,281 Ewing Dec. 24, 1940 2,396,674 Braunsdorf Mar. 19, 1946 2,910,611 Jordan Oct. 27, 1959

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