US2317032A

US2317032A - Terminal structure for electric lamps

Info

Publication number: US2317032A
Application number: US438348A
Authority: US
Inventors: Carl A Cotman; Daniel K Wright
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1942-04-09
Filing date: 1942-04-09
Publication date: 1943-04-20
Anticipated expiration: 1960-04-20
Also published as: BE476585A; GB564493A

Description

April 3' c. A. COTMAN ETAL TERMINAL STRUCTURE FOR ELECTRIC LAMPS lnvewtors: Carl A. Cowman, DanieL KMQWC, b5 Their A'tcorneg Filed April 9. 1942 Patented Apr. 20, 1943 2.31am TERMINAL s'rnvc'roas roa smormc ram-s can A. Cotman and Daniel K. Wright, Cleveland Heights, Ohio, assignors to General Electrio Company, a corporation of New York Application April 9, 1942, Serial No. 438,348

9 Claims. (Cl. 176-32) Our invention relates to electric incandescent lamps and similar devices comprising a bulb having one or more electrical energy translation elements sealed therein and a base mounted on said bulb. More particularly, our invention relates to a base or terminal structure for such devices and particularly for the device disclosed in our copending application Serial No. 402,120, filed July 12, 1941, of which the present application is a continuation-impart.

. One object of our invention is to provide an electrical device having a base or terminal arrangement which is simple in construction and relatively inexpensive, and which is firmly secured to the envelope of the device by mechanical means.

Another object of our invention is to provide a unitary and rigid base structure for connection to the terminal elements of electrical devices of the above type, the said base serving to minimize the various strains to which the said terminal ele ments are subjected during the use of the device.

Still another object of our invention is to provide a base structure for electrical devices of the above type which is formed of a minimum number of parts and a. minimum amount of material, and which serves to protect the exhaust tip extending from the envelope of the device.

Further objects and advantages of our invention will appear from the following description of species thereof and from the accompanying.

drawing in which:

Fig. 1 is a side elevation, partly in section, of an electric incandescent lamp provided with a base and terminal arrangement comprising our invention; Fig. 2 is a fragmentary rear elevation of the base portion of the lamp shown in Fig. 1;

Fig. 3 is a fragmentary perspective view of the base portion of the lamp shown in Fig. 1; Fig. 4 is a fragmentary sectional view, on an enlarged scale, of a modified form of base according to our invention; Fig. 5 is a fragmentary rear elevation and Fig. 6 is a perspective view of the modifled lamp base shown in Fig. 4

Referring to the drawing, the lamp there shown is of the sealed beam type such as described and claimed in U. S. Patents 2,148,314 and 2,148,315, issued February 21, 1939, to D. K. Wright, and comprises a sealed glass bulb or envelope i0 consisting of a preformed pressed glass concave reflector section i l of heat resisting glass and a cover glass or lens section I! also of heat resisting pressed glass sealed together at their peripheries by fusion. The interior surface I 3 of the reflector section H is of any suitable optical shape, preferably that of a paraboloid, and is covered with a reflecting metallic coating I4, preferably aluminum, so as to form a reflecting surface. The exterior of the reflector section I i, adjacent the apex thereof, is formed with three glass bosses l5 arranged in triangular formation about the apex of the reflector section, as shown in Fig. 2, two of the bosses being disposed on opposite sides of the apex of said reflector and the other boss being disposed directly above said apex. Each of the bosses i5 is provided with a concentric opening it extending through the wall of the reflector section and communicating with the interior oi the lamp envelope l0.

Mounted within the envelope iii in definite optical relation to therefiecting surface it thereof, is a pair of spaced electrical energy translation elements or filaments l1, l8, preferably in the form of concentrated linear coils of a suitable metallic refractory material, such as tungsten. The said filaments are arranged parallel to one another in more or less side-by-side relation and in the focal plane of the parabolic reflecting surface M, with one filament i! (the major filament) disposed at the focal point of the reflecting surface it and the other filament I8 (the minor filament) offset a slight distance above and to one side of the said focal point. The filaments are supported within the bulb ill by, and electrically connected at their ends to, a plurality of relatively heavy rigid leading-in wires l9 which extend through the openings IS in the reflector section to a plurality (3) of closed metal cups or thimbles 20 mounted on the exterior of the reflector section, with their axes parallel to the axis of the reflector section I I, and each covering one of the openings l6 therein.

The said thimbles 20 have their edges or rims fused to and sunk and embedded in the glass of the bosses 5 so as to form a hermetic seal therebetween, similar to that described and claimed in U. S. Patent 2,098,080 D. K. Wright, issued November 2, 193?.

The cups or thimbles 20 are made of a metal to which the glass of the lamp envelope ID will wet or adhere, and should preferably have an expansion as near as possible to that of the glass. For heat-resistant glass of the type known as Pyrex," the thimbles 20 are preferably made either of an iron-nickel-cobalt alloy known as Fernico or an iron-nickel alloy containing approximately 42 per cent nickel. Each of the metal thimbles 20 is formed with a small tubular projection or nipple 2i extending outwardly from the outer end of the thimble. The inner wire leads 18 extend into the thimble 20 and are firmly securedthereto by means of a suitable metallic fusible material 22, such as hard solder, so as to provide an electrical connection between the leading-in wires and the metal cups as well as a firm support for the said wires and the filaments ll, l8.

The lamp envelope I9 is exhausted and filled with a suitable gas, such as argon or nitrogen or mixtures thereof, through an exhaust tube 23 attached to the reflector section at the apex thereof and communicating with the interior of the lamp envelope through an opening 24 extending through the wall of the reflector section through the apexthereof. After the gas filling, is introduced into the lamp envelope, the exhaust tube 23 is tipped off to provide a flattened tip 25, as.

shown in the drawing. Theflattened exhaust tube tip 25 is disposed in aplane at an angle to the plane passing through the axes of the two diametrically opposite metal thimbles 20.

Mounted on the metal thimbles is a lamp base or terminal structure 28 comprising our invention. The said base structure 20 comprises a small rectangular plate-shaped body member 2! of suitable insulating material, and a plurality (three) of L-shaped metal contact lugs or prong members 28 each secured to the insulator member 21 and to one of the metal thimbles 20. The insulator plate member 21 may be made, for instance, of a suitable plastic material, such as, for instance, those commercially known as Textolite, Bakelite, etc.

The L-shaped contact prongs 28 are formed with mounting leg portions 29 and connector leg portions 30, and are mounted on the insulator plate member 21 in triangularformation thereon with the said connector leg portions 30 extending perpendicularly outward in the same direction from one of the surfaces of the plate-shaped insulator member 21. The connector leg portions 30 extend through the insulator member 21 through suitable openings 3| therein, and are each provided.with a bendable locking lug or tongue 32 which is punched out of the said connector leg portion 30 and is bent-over against the insulator member 21 so as to extend in a direction the same as the mounting leg 29 and firmly clamp said member 21 between the mounting leg portion 29 and the said locking lug or tab 32 of each contact prong. The mounting leg portions 29 of the contact prongs 28 extend outwardly from the connector leg portions 30 and project from the edges of the insulator member 21 so as to form projecting ear portions which are provided with integral eyelets 33 (Fig. 1)

.punched therefrom, the said eyelets being of wardly from the envelope ina direction parallel to the axis of the reflector section II, as shown in Figs. 1 and 3, and with the contact'prong eyelets 33 fitting over the nipples2'l on the. thimbles 20 and secured thereto by clamping, or by a readily fusible metallic material 34 such as solder, as shown. In this way a firm'and secure mounting portant where the lamp terminal elements are of the two-piece type, such as disclosed in United States Patent 2,098,080 D. K. Wright, issued November 2, 1937, in which a terminal post extends through the thimble 20 and is brazed thereto. In such case, the distribution of the strains to all three of such two-piece terminal elements serves to minirriize the possibility of the brazed joint between the two parts of any one of said elements becoming loosened and separated by such strains with resultant destruction of the hermetic seal between such parts.

.The insulator member'2l, which is disposed across the rear or thimbled portion of the reflector section II, therefore more Or less overlies the tipped exhaust tube 23 so as to protect and shield the same from impacts which might cause breakage of said tube. The said insulating member, however, is provided with an elongated opening or aperture 35 adjacent its middle portion, which opening extends diagonally of the rectangular-shaped insulator member so as to be in alignment with and therefore accommodate the flattened exhaust tube tip 25 should the latter extend too far out from the lamp envelope l0.

Referring to Figs. 4-6, the modified base construction 36 there shown is similar to the base of the base on the lamp envelope III is provided;

The insulator member 21 serves to distribute any forces to which the contact prongs 28.may be subjected during service of the lamp, to all'three of the contact prongs and therefore to all three of the solder joints or connections between said prongs and the thimbles 2|, thus minimizing the possibility of rupture of the saidsolder joints.

This strain-distributingfeature is especially im- 76 26 shown in Figs. 1-3 but differs therefrom in the size and shape of the insulator member 31 and in the manner of attachment of the contact prongs 28 to said member. The insulator member 31 of the modified base construction is of more or less triangular shape, as shown particularly in Figs. 5 and 6, and is somewhat larger than the rectangular insulator 21 of Figs. 1 -3, the said member 31 being sufiiciently large to at least surround the integral eyelets 33 on the rzrgounting leg portions 29 of the contact prongs The contact prongs 28 are mounted on the insulator member 31 in the same triangular manner as in the previous form of the invention, but with the mounting legs 29 engaging the upper or top surface 38 of the insulator instead of the under surfaceas before. The eyelets 33 on the mounting legs 29 extend through the insulator 31 through suitable openings therein, and are rolled or peaned over onto the under surface 39 of said member to thereby provide a firm attachment of each contact prong 28 to the insulator member at a point adjacent the free end of the so as to extend from the mounting leg portion 29 in a direction opposite to that of the connector leg portion 30. The locking lugsor tabs 40 ex-.

tend through suitable openings in the insulator a member 3! and are bent over onto the under'sur face 39 of saidmember, preferably in a direction,-

oppositeto that of the mounting-legs 29, so as to I firmly clamp the contact prongs to theinsulator member 31; -The eyelets- 33 and locking lugs thusprovide a two-point, and therefore stronger, attachment or support of each'contact prong 28 on'the insulator member 31.

The modified base 36 is mounted on the lamp envelope ill in the same way as the base 26,- i. e.,

with'the connector leg portions 38 of the conreflector section II, and with the contact prong eyelets 33 fitting over the nipples 2| n the thimbles and secured thereto byclampinz, or by solder 34 as shown. As in the previous form of the invention, the insulating body member 31 serves to insulate the three contact prongs 28 and to distribute any strains imposed on such prongs to all three points of connection between the base and the three thimbles 20. Likewise, the insulator 31, which extends across the rear or thimbled portion of the reflector section II so as to more or less overlie the tipped exhaust tube 23 and therefore protect or shield the same from impacts which might cause its breakage, is also provided with an opening or aperture 4| adjacent its middle portion for the accommodation therein cf the exhaust tube tip 25 should the latter extend an excessive distance out from'the lamp envelope I 0.

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

1. An electrical device comprising a'glass envelope having a plurality of metal terminal elements mounted exteriorly of said envelope and each provided with a cylindrical extension, and a base structure for said device comprising an insulator member and a plurality of metal contact prongs rigidly secured to said insulator member, said contact prongs havingintegral eyelets fitting over the said extensions on said terminal elements and being rigidly secured thereto.

and having their edges fused into a wall of said envelope around openings therein, said cup members having cylindrical extensions and being imperforate so as to hermetically seal said openings, and a base structure for said device comprising an insulator member and a plurality of metal contact prongs rigidly secured to said insulator member, said contact prongs having integral eyelets fitting over the said extensions on said cup members and being rigidly secured thereto.

3. An electrical device comprising a glass envelope having a plurality of metal terminal elements mounted exteriorly of said envelope and each provided with a cylindrical extension, a tipped exhaust tube extending outwardly from said envelope at a point between said terminal elements, and a base structure for said device comprising an insulator member disposed between said terminal elements so as to shield said exhaust tube and having an aperture for the accommodation of the tip of said exhaust tube, and a plurality of metal contact prongs rigidly secured to said insulator member and provided with integral eyelets fitting over the said extensions on said terminal elements and rigidly secured thereto.

4. An electrical device comprising a glass envelope having three metal terminal elements mounted exteriorly of said envelope in triangular formation thereon and each provided with a ctlindrical extension, and a base structure for said device comprising an insulator plate member and three metal contact prongs rigidly secured to said insulator plate in triangular formation corresponding to that of the terminal elements on said envelope, said contact prongs having portions projecting outwardly of the edges of said insulator plate and provided with integral eyelets fitting over the said extensions on said terminal elements and rigidly secured thereto.

5. An electrical device comprising a glass envelope having three metal terminal elements mounted exteriorly of said envelope in triangular formation thereon and each provided with 9. cy-

lindrical extension, and a base structure for said device comprising an insulator plate member and three L-shaped metal contact prongs mounted on said insulator plate in triangular formation thereon, each of said L-shaped contact prongs having one leg thereof extending through and projecting perpendicularly outward from said insulator plate and provided with a locking lug bent over onto said insulator plate to thereby firmly clamp said prong to said insulator plate, and the other legs of said prongs projecting outwardly beyond the edges of said insulator plate and having integral eyelets punched out of the said projecting portions thereof, said eyelets fitting over the said extensions on said terminal elements and being rigidly secured tlereto.

6. An electrical device comprising a glass envelope having three metal terminal elements mounted exteriorly of said envelope in triangular formation thereon and each'provided with a cylindrical extension, and a base structure for said device comprising an insulator plate member and three L-shaped metal contact prongs mounted on said insulatorplate in triangular formation thereon, each of said L-shaped contact prongs having one leg thereof extending perpendicularly outward from said insulator plate and provided with a locking lug extending through and bent over onto said insulator plate to thereby firmly clamp said prong to said insulator plate, and the other legs of said prongs having integral eyelets extending through said insulator plate and having their free rim portions peaned over onto said insulator plate to thereby firmly clamp said prongs to said insulator plate, said eyelets fitting over the said extensions on said terminal elements and being rigidly secured thereto.

'7. A base for an electric device comprising an insulator plate member and a plurality of L- shaped contact prongs rigidly secured to said insulator plate each with one leg thereof resting flat against a surface of said insulator plate and the other leg thereof extending perpendicularly outward from said insulator plate, said contact prongs having locking lugs punched therefrom and bent over against said insulator plate to thereby firmly clamp said prongs to said insulator plate, and said one of said legs having integral eyelets punched therefrom for engagement with terminal elements on said device.

8. A base for an electric device comprising an insulator plate member and a plurality of L- shaped metal contact prongs rigidly secured to said insulator plate each with one leg thereof resting fiat against a surface of said insulator plate and the other leg extending through and projecting perpendicularly outward from said insulator plate, said contact prongs having looking lugs punched therefrom and bent over against said insulator plate to thereby firmly clamp said prongs to said insulator plate, and said one of said legs projecting outwardly beyond the edges of said insulator plate and having integral eyelets punched out of the projecting portions thereof for engagement with terminal elements on said electric device.

9. A base for an electric device comprising an insulator plate member and a plurality of L- shaped metal contact prongs rigidly secured to said insulator plate each with one leg thereof resting fiat against a surface of said insulator 4- asmosz plate and the other leg thereof extending persaid electric device, said eyelets extending pendicularly outward from said insulator plate, through said insulator plate and having their said contact prongs having bendable locking lugs free rim portions peaned over onto said insulator punched therefrom and bent over against said plate to thereby firmly clamp said prongs to said insulator plate to thereby firmly clamp said 5 insulator plate. prongs to said insulator plate, and said one of CARL A. COTMAN.

said legs having integral eyelets punched there- DANmL K. WRIGHT. from for engagement with terminal elements on i V I