US3785020A

US3785020A - Method of basing electrical devices

Info

Publication number: US3785020A
Application number: US00197662A
Authority: US
Inventors: S Boros
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1971-11-11
Filing date: 1971-11-11
Publication date: 1974-01-15
Anticipated expiration: 1991-01-15
Also published as: FR2160181A5

Abstract

A method of electrically connecting an outer wire lead of an electric lamp to the metal shell of the base thereof by flattening a section of the wire lead and soldering the flattened section flatwise to the inner side of the base shell rim.

Description

States Patent ,1191

1; W 0 mi 11 1e [11] 3,785,020 was Jan. 15, 1974 [54] METHOD OF BASING ELECTRICAL 3,172,455 3/1965 Rively et al 72/323 x D S 3,047,765 7/1962 Vichill 313/318 [75] Inventor: Steve Burns, Memphis, Tenn. FOREIGN PATENTS OR APPLICATIONS [73] Assignee: General Electric Company, 611,304 12/1960 Canada 29/25.11

Schenectady, NY.

Primary Examiner-Charles W. Lanham [22] Ffled' 1971 Assistant Examiner.l. W. Davie [21] Appl. N0.: 197,662 Att0rney.lames J. Lazna et al.

[52] U.S. C1. 29/25.13, 313/315 57 ABSTRACT [51] Int. Cl. H0lj 9/18 [58] Field of Search 29/251 1, 25.13; A metlmd elecmcally cmmectmg lead 313/315, 318 of an electric lamp to the metal shell of the base thereof by flattening a section of the wire lead and sol- [56] References Cited dering the flattened section flatwise to the inner side UNITED STATES PATENTS Of the base 3,413,054 11/1968 Richards ct al 313/315 X 3 Claims, 4 Drawing Figures PATENIEBJMI 1 5 mm ITWVGTITOTI S teve Bovos y? M a i 1 METHOD OF B-ASING ELECTRICAL DEVICES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates, in general, to the manufacture of electric lamps and similar devices, and more particularly to a method of electrically connecting a wire lead of such a device to the metal shell of the base thereof.

2. Description of the Prior Art I Certain types of so-called subminiature size electric incandescent lamps, such as that commercially designated as the No. 327 lamp, are in general use at present for indicator and instrument lighting applications. Such lamps are customarily comprised of a tubular glass lamp bulb or envelope of very small size, e.g., around 7/32 inch diameter, on one end of which is mounted, axially of the bulb, a lamp base in the form of a metal shell of slightly larger diameter than that of the bulb and flanged at its closed end so that the lamp can be inserted and pushed bulb end first into a lamp socket in an instrument or other socket-supporting panel. The bulb contains a filament connected across a pair of current lead-in wires which are sealed through the side wall of the bulb at the neck end thereof by a conventional butt-type seal. The seal or neck end of the bulb extends into an open end of and is secured to the base shell by the customary ring of lamp basing cement, and the wire leads are electrically connected to the metal shell and end contact, respectively, of the lamp base. The open inner end of the base shell into which the bulb extends is formed with an inwardly rolled or inturned curved lip within which the bulb is snugly received to center it in place more or less axially of the base shell.

The most common manner of electrically connecting the so-called side wire lead of an electric lamp to the base shell is to position the wire lead so as to extend out between the wall of the lamp bulb and the rim of the base shell when the base is placed in mounting position on the neck end of the bulb, and to then solder the wire lead to the outer side of the base shell adjacent its rim. Such a procedure, however, results in the formation of a small mound or accumulation of solder on the outer side of the base shell and protruding therefrom. For the intended usage of the particular subminiature indicator type lamps referred to above designed for bulb-endfirst slide-in insertion of the lamp into the lamp socket, such protruding solder accumulations on the base shells would not be permissible since they would, in effect, block the endwise sliding insertion movement of the lamp into its socket. Accordingly, some other way of basing these types of lamps had to be developed which would avoid the presence of any such solder protrusions on the base shells.

To this end, the basing procedure ultimately developed for such purpose and heretofore in customary use comprises the steps of forming the base shell with an apertured inward indent or recess in its side wall near the closed outer end of the base through the aperture of which indent the side wire leadis threaded and cut off flush with the outer side of the base shell, after which the cut-off wire lead is then soldered to the base shell within the indent therein. With this modified basing procedure, the solder accumulation at the wire-tobase shell solder connection is concealed entirely within the indent in the base shell and thus does not protrude from the outer side thereof. However, be-

cause of the necessity for threading the side wire lead through the side aperture in the base shell, such a modified basing procedure precludes the use of conventional type automatic base-threading mechanisms similar to that disclosed in US Pat. No. 2,120,877-Uber, for example, which are customarily employed in the lamp-making art, because of the substantial cost saving realized therefrom, to automatically feed and position lamp bases in mounting position on the glass bulbs of electric lamps, with the end or center contact wire lead of the lamp bulb extending through the customary end contact eyelet of the base in position for soldering thereto. In their customary manner of operation, these automatic base-threading mechanisms lower the bases down over and guide the upstanding center contact wire lead, extending endwise from the lamp bulb, into and upwardly through the opening in the end contact eyelet of the base. Obviously, the presence of a side wire lead extending laterally from the lamp bulb and required to be threaded into a side aperture in the shell of the lamp base, as in the case of the modified lamp basing procedure referred to above, would interfere with the lowering movement of the lamp base, by such automatic base-threading mechanisms, down over the upstanding center wire lead of the lamp and into mounting position on the end of the lamp bulb.

SUMMARY OF THE INVENTION It is an object of the invention, therefore, to provide a novel method of electrically connecting the side wire lead of an electric lamp to the metal shell of the lamp base thereof.

Another object of the invention is to provide a novel method of electrically connecting the side wire lead of an electric lamp to the metal shell of the lamp base thereof which method not only avoids the formation of any solder accumulation protruding from the outer side of the base shell but at the same time lends itself to the use of conventional automatic lamp base-threading mechanism for feeding the base into mounting position on the end of the lamp envelope.

Still another object of the invention is to provide a novel method of basing an electric lamp which avoids the formation of any solder accumulation on the outer side of the base shell and at the same time permits the use of conventional automatic base-threading mechanism for feeding the base into mounting position on the envelope end.

Briefly stated, in accordance with one aspect of the invention, the side wire lead of an as yet unbased electric lamp is formed, adjacent its seal through the envelope wall, with a flattened section which is provided with a coating of solder and an overcoating of solder flux and then wedged flatwise between the wall of the glass lamp envelope and the rim of the metal shell of a lamp base on placement thereof in mounting position on the envelope following which the base shell rim is then heated to melt the solder coating on the flattened wire lead section and solder it to the inside wall of the base shell.

F urther objects and advantages of the invention will appear from the following detailed description of a species thereof and from the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a perspective view showing the flattening of the side wire lead of an electric lamp in accordance with the lamp basing method comprising the invention;

FIG. 2 is a perspective view showing the manner of formation and positioning of the two wire leads of the electric lamp in readiness for the feeding and positioning of the lamp base thereon, with the flattened section of the side wire lead shown coated with solder;

FIG. 3 is an elevation showing the lamp base in mounting position on the lamp envelope in readiness for attachment thereto and also showing the side Wire lead formed in readiness for the soldering thereof to the inside of the base shell; and

FIG. 4 is an elevation, on an enlarged scale, of the completed lamp after soldering of the side wire lead to the base shell and trimming off the outer end portion of the side wire lead exposed beyond the rim of the base shell.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the invention is there illustrated as applied to the manufacture of a subminiature electric incandescent lamp such as that commercially designated as the No. 327 type lamp customarily used for indicator and instrument lighting purposes and comprising a sealed evacuated tubular glass bulb or envelope 1 of very small size, e.g., around 7/32 inch diameter and A inch or so in length, which is closed off at its neck end 2 by the residue of an exhaust tube tip 3. Sealed into the envelope 1 is a lamp mount 4 comprising a filament 5, which may be in the form of a coiled tungsten wire, connected at its ends across a pair of spaced metal wire leads or lead-in

wires

6 and 7 which are bridged and held in spaced relation by a glass support bead 8 fusion sealed to the

wires

6, 7. As shown, the wire leads 6, 7 are sealed through the side wall 9 of the envelope 1 at the neck end 2 thereof, and at locations more or less diametrically opposite one another, by a conventional butt-type seal. A lamp base 10 comprising a metal shell 11 and a metal end contact eyelet 12 secured together by an insulator ring 13 is mounted on the neck end 2 of the envelope 1. The neck end 2 of the envelope 1 extends into the open end of, and is secured in place to the base shell 11 by a customary ring 14 of lamp basing cement. As shown, the base shell 11 is of slightly larger diameter, e.g., around 1/32 inch or so larger diameter, than the outside diameter of the tubular glass envelope or bulb 1 so as to -permit bulbend-first insertion of the lamp into a lamp socket. The open inner end of the base shell 11 into which the envelope 1 extends is formed with an inwardly rolled or inturned curved lip or rim 15 within which the envelope 1 is snugly received to center it in place more or less axially of the base shell. One of the wire leads, e.g., wire lead 6, hereinafter referred to as the side wire lead, is electrically connected to the base shell 11 by soldering it thereto, while the other or center wire lead 7 is soldered to the center or end contact eyelet 12 of the lamp base 10.

In mounting the base 10 on the lamp envelope 1 and electrically connecting the side wire lead 6 to the metal shell 11 of the base in the manner according to the invention, the outer portion 6 of the wire lead 6 extending outwardly of the envelope wall 9 from its seal therethrough is first formed so as to extend in a substantially straight direction laterally outward from the envelope 1, as shown in FIG. 1. The outer end portion 7' of the other or center contact wire lead 7 is also preferably formed to extend in a substantially straight direction laterally outward from the envelope 1 and angled toward the tip end 3 thereof, as shown in FIG. 1. At least a section 16 of the outer side wire lead portion 6' adjacent its point of emergence from the lamp envelope 1 and which, in the final mounted position of the base 10 on the envelope end 2, will extend and intervene between the envelope wall and the rim 15 of the base shell 11, is then flattened in a plane transverse to the axis of the envelope 1, by compressing it between opposed flattening jaws 17, so that when the outer wire lead portion 6' is bent to extend alongside the side wall of the envelope toward the'end thereof opposite its neck end 2, the flattened section 16 will lie flatwise against and tangent to the envelope side wall. The flattened section 16 of the side wire outer lead portion 6' is then provided with a coating 18 of solder, as by first applying a solder flux coating thereon and then pressing the fluxed flattened section 16, by means of a soldering iron, down into a pool of molten solder carried on a supporting platen.

After the application of the solder coating 18 thereto, the outer portions 6' and 7' of the wire leads 6, 7 are then reformed to the shape and positioning shown in FIG. 2. As there illustrated, the outer wire lead 6 is bent to position the portion 19 thereof adjacent its point of emergence from the side wall 9 of the envelope 1, and including at least a portion 19 of its flattened section 16, to extend alongside the outer side of the envelope in a direction toward the end thereof opposite its neck end 2, the remaining outer end portion 20 of the outer wire lead 6 being left to extend as before in a direction laterally outward from the envelope side wall. The center or end contact wire lead portion 7 is bent over the tip end 3 of the envelope 1 to extend endwise therefrom and substantially coaxially thereof. With the outer wire lead portions 6', 7' thus reformed and positioned, a lamp base 10 having a ring 14 of uncured conventional type lamp basing cement adhered to the inner side of its base shell adjacent but removed a short distance inwardly from the edge of its rim 15, is then threaded over the end contact wire lead portion 7 and placed over the neck end 2 of the envelope 1 in its mounting position thereon as shown in FIG. 3, with the ring 14 of basing cement in contact with the side wall 9 of the envelope 1 and with the end or center contact wire lead portion 7 projecting through the aperture 21 in the end contact eyelet 12 of the base 10 and the bent portion 19 of the outer side wire lead 6, including the flattened section 19 thereof, extending and wedged between the rim l5 ofthe base shell 11 and the side wall of the lamp envelope 1. Because the side wire outer lead 6 is bent to extend alongside the envelope l and toward the end thereof opposite its neck end 2 at the time of threading of the base 10 over the end contact outer wire lead 7' and positioning thereof on the neck end 2 of the envelope 1, there is nothing to interfere therefore with the placement of the base 10 over the neck end 2 of the lamp envelope other than the necessity for assuring the threading of the end contact outer wire lead 7' through the aperture 21 in the end contact eyelet 12 of the base 10. Consequently, the lamp basing method according to the invention readily lends itself and is adapted to the use of auto matic base-threading mechanism such as is commonly employed in the lamp-making art for automatically threading lamp bases over the end .or center contact wire lead of electric incandescent lamps and positioning them in place on the neck ends of the lamp envelopes, thereby affording the opportunity of realizing the considerable cost savings which are obtainable by the employment of such automatic base-threading and feeding mechanism.

With the base 10 thus placed in mounting position on the neck end 2 of the lamp envelope 1, the envelope and the base 10 are then axially displaced away from one another to expose the flattened wire lead portion 19' of the bent wire section 19 extending alongside the envelope wall, whereupon a liquid solder flux is then suitably applied, as by means of a dauber for instance, to the exposed flattened wire lead portion 19' extending alongside the envelope wall. The envelope 1 and base 10 are then moved axially together and repositioned relative to one another to again locate the base in its final mounting position on the neck end 2 of the envelope, whereupon the exposed outer end portion 20 of the outer wire lead 6 is bent upwardly, while the assembled lamp envelope 1 and base are supported as shown in a base end up position, to extend from the rim 115 of the base shell ll at an appreciable angle, for example, around 45 to the horizontal, in order to thereby induce any of the previously applied liquid solder flux present on the exposed portion 20 of the outer wire lead 6' to flow back downwardly therealong and into contact with the rim 15 of the base shell 11.

While the envelope 1 and base 10 are thus supported in their assembled position with the base end 10 positioned up, the rim 15 of the base shell 11 is suitably heated, as by means of gas fires directed thereagainst, to melt the solder coating 18 on the flattened wire lead section 19' wedged between the base shell rim l and the envelope side wall so as to solder the flattened section 19 to the inside of the base shell 11 as indicated at 22 in FIG. 4, thus effecting the electrical connection of the wire lead 6 to the base shell. The heating of the base shell to form the solder connection 22 also acts to cure the ring 114 of basing cement on the inside wall of the base shell so as to cause it to adhere to the side wall of the glass envelope 1, thereby fixedly securing the base in place on the neck end 2 of the envelope.

With the electrical connection of the side wire lead 6 to the base shell 11 and the securing of the base 10 to the glass envelope 1 thus effected, the lamp basing operation is then completed by trimming off the excess portion 20 of the side wire lead 6' exposed beyond the rim of the base shell 11, as by breaking it off at the rim 15 of the base shell, and then trimming off the excess portion of the end contact wire lead 7 exposed beyond the end contact eyelet 12 of the base 10 and soldering the remaining wire lead portion 7' to the eyelet, as indicated at 23, in the manner customary in the lamp-making art.

By forming, through the practice of the invention, the solder connection of the outer side wire lead 6' to the inside of the rim 15 of the metal base shell 11 instead of to the outside thereof as in prior customary lampbasing practice, the side wire lead solder connection 22 therefore is located entirely within the confines of the base shell 11 and thus does not form a solder accumulation protruding from the outer side wire thereof such as would interfere with the bulb-end-first sliding insertion of the completed lamp into a lamp socket. Also,

since with the manner of forming the side wire lead connection to the base shell in accordance with the invention the base 10 can be automatically threaded over the end contact wire lead of the lamp and placed in mounting position on the neck end of the envelope by the employment of conventional type automatic base threading mechanism, the lamp basing method according to the invention therefore affords the opportunity and highly important advantage of realizing the considerable manufacturing cost saving inherent in the use of such automatic base-threading mechanism.

I claim:

1. The method of electrically connecting the metal shell of a lamp base to be mounted on an end of the tubular-shaped glass envelope of a miniature electric lamp to an outer wire lead sealed through and emerging from the side wall of said envelope adjacent the said end thereof, which method comprises the steps of positioning the said outer wire lead to extend in a substantially straight direction laterally outward from the said envelope, flattening that section of the said laterally extending outer wire lead which, in the final mounted position of the base on the said envelope end, will extend and intervene between the envelope wall and the rim of the base shell, the said flattening of said wire lead section being in a plane transverse to the axis of said envelope, applying a coating of solder to the said flattened wire lead section, bending the portion of said outer wire lead adjacent its point of emergence from the envelope, and including at least a portion of its said flattened section, to extend alongside the outer wall of said envelope in a direction toward the other end thereof, with the plane of the bent flattened wire lead portion disposed tangent to the envelope wall, applying a solder flux to at least the said bent flattened wire lead portion extending alongside said envelope wall, positioning the lamp base over the said end of the envelope with the said bent flattened wire lead portion extending and wedged between the wall of said envelope and the rim of the metal shell of said base, and then heating the rim of the base shell and the said bent flattened wire lead portion to melt the said solder coating thereon and form a solder connection of the wire lead to the base shell.

2. The method of electrically connecting the metal shell of a lamp base to be mounted on an end of the tubular-shaped glass envelope of a miniature electric lamp to an outer wire lead sealed through and emerging from the side wall of said envelope adjacent the said end thereof, which method comprises the steps of positioning the said outer wire lead to extend in a substantially straight direction laterally outward from the said envelope, flattening that section of the said laterally extending outer wire lead which, in the final mounted position of the base on the said envelope end, will extend and intervene between the envelope wall and the rim of the base shell, the said flattening of said wire lead section being in a plane transverse to the axis of said envelope, applying a coating of solder to the said flattened wire lead section, bending the portion of said outer wire lead adjacent its point of emergence from the envelope, and including at least a portion of its said flattened section, to extend alongside the outer wall of said envelope in a direction toward the other end thereof, with the plane of the bent flattened wire lead portion disposed tangent to the envelope wall and with the remaining portion of said outer wire lead beyond said bent flattened wire lead portion extending laterally outward from the envelope, applying a liquid solder flux to at least the said bent flattened wire lead portion extending alongside said envelope wall, placing the lamp base over the said end of the envelope positioned with its said end up and with the said bent flattened wire lead portion extending downwardly and wedged between the wall of said envelope and the rim of the metal shell of said base, bending upwardly the said remaining outer end portion of said outer wire lead exposed beyond the rim of the base shell to extend angularly upward at an appreciable angle from the said base shell rim so as to thereby cause the said liquid solder flux on the said upwardly angled bent exposed portion of said outer wire lead to flow downwardly therealong into contact with the rim of the base shell, and then heating the rim of the base shell and the said bent flattened wire lead portion to melt the said solder coating thereon and form a solder connection of the wire lead to the base shell.

3. The method of electrically connecting the metal shell of a lamp base to be mounted on an end of the tubular-shaped glass envelope of a miniature electric lamp to an outer wire lead sealed through and emerging from the side wall of said envelope adjacent the said end thereof, which method comprises the steps of positioning the said outer wire lead to extend in a substantially straight direction laterally outward from the said envelope, flattening that section of the said laterally extending outer wire lead which, in the final mounted position of the base on the said envelope end, will extend and intervene between the envelope wall and the rim of the base shell, the said flattening of said wire lead section being in a plane transverse to the axis of said envelope, applying a coating of solder to the said flattened wire lead section, bending the portion of said solder-coated wire lead adjacent its point of emergence from the envelope, and including at least a portion of its said flattened section, to extend alongside the outer wall of said envelope in a direction toward the other end thereof, with the plane of the bent flattened wire lead portion disposed tangent to the envelope wall and with the remaining portion of said outer wire lead beyond said bent flattened wire lead portion extending laterally outward from the envelope, placing the lamp base in its mounting position on the said end of the envelope positioned with its said end up, with the said bent flattened wire lead portion extending downwardly alongside and wedged between the envelope wall and the rim of the base shell and with the base shell enclosing the said bent flattened wire lead portion and with the remaining portion of said outer wire lead beyond said bent flattened wire lead portion extending laterally outward from the envelope, vertically displacing the said envelope and base away from one another to expose the said bent flattened wire lead portion extending alongside said envelope wall, applying a liquid solder flux to at least the said exposed flattened wire lead portion extending alongside said envelope wall, repositioning the said envelope and base relative to one another to again locate the base in its mounting position on the said end of the envelope, bending upwardly the said remaining outer end portion of said outer wire lead exposed beyond the rim of the base shell to extend angularly upward at an appreciable angle from the said base shell rim so as to thereby cause the said liquid solder flux on the said upwardly angled bent exposed portion of said outer wire lead to flow downwardly therealong into contact with the rim of the base shell, and then heating the rim of the base shell and the said bent flattened wire lead portion to melt the said solder coating thereon and form a solder connection of the wire lead to the base shell.