US2576363A - Socket for series lamps and string thereof - Google Patents

Description

NOW 1951 c. M. RlVELY EI'AL SOCKET FOR SERIES LAMPS AND STRING THEREOF Filed May 17, 1947 Patented Nov. 27, 1951 UNITED STATES PATENT OFFICE SOCKET FOR SERIES LAMPS AND STRING THEREOF Application May 17, 1947, Serial No. 748,776

2 Claims. I

This invention relates to a socket for series lamps and, more particularly, to one which will allow the remainder of the lamps in a string to keep burning if one, or a substantial proportion of the lamps, in said string burn out or are removed.

The principal object of our invention, generally considered, is to produce a socket for lamps adapted to operate in series, as in a string of Christmas tree or other lamps, said socket containing material bridging the space between leads from lamp-connecting tabs to the power supply through associated similar sockets.

Another object of our invention is to provide a socket for an electric lamp comprising tabs for connectively-receiving contact elements of said lamp, with leads extending from said tabs for connection through associated similar sockets to a source of power, and material which is normally substantially non-conducting, but will break down and conduct when the voltage is increased a predetermined extent and again revert to substantially non-conducting condition when the voltage is reduced, disposed between said leads, whereby the voltage across the socket with the lamp removed is approximately the same as with the lamp in the socket, and a substantial proportion of the lamps may be removed and the string relighted if the line voltage is removed, while more than one half of the lamps in the string may be removed While leaving the remainder still burning.

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

Referring to the scale drawing:

Figure 1 is a. fragmentary elevational view, approximately full size in the drawing accompanying this application, of a string of lamps involving one embodiment of our invention, and which may be used for decorating a Christmas tree.

Figure 2 is an axial sectional View on a larger scale of one of the sockets of said string with a fragmentary portion of a lamp in place.

Figure 3 is a transverse sectional view of the socket, on the line III-Ill. of Figure 2, in the direction of the arrows.

Figure 4 is a transverse sectional view on the line IVIV of Figure 2'.

Figure 5 is a perspective view of one of the lamp contact receiving tabs, separated from its socket.

Figure 6 is a fragmentary axial sectional view,

corresponding to Figure 2 but showing a modification.

Figure '7 is a transverse sectional view on the line VIIVII of Figure 6, in the direction of the arrows.

Figure 8 is an axial sectional view on the line VIII-VIII of Figure '7, in the direction of the arrows.

Figure 9 is a view corresponding to Figure 2, but showing another modification.

Referring to the drawing in detail, and first considering the embodiment of our invention illustrated in Figures 1 to 5, inclusive, there is shown a string or series of sockets all formed as designated at H, H ll (in Figure 9) N or H or some formed one way and others another way or other ways, which may hold lamps adapted to operate on 5.9 volts with a current of .22 ampere, as specifically disclosed as a preferred embodiment in the Way application subsequently referred to, for Christmas tree decoration or other purposes, receiving power through a contact plug l2 and lines I3 and M from an electrical utility outlet IE, or other source of power. Each socket may be as shown in detail in Figures 2 to 5, inclusive, that is, it may consist of a hollow cylindrical element or sleeve l6 of paper or other insulating material, in which is mounted an insulating plug member [1 or one formed with a pair of apertures l8 and I9 extending therethrough. The inner ends of the apertures, cavities or pockets l8 and 9 are restricted, as indicated at 45 and 41, and countersunk at 48 and 49 to guidingly receive the contact elements or prongs 25 and 26 of lamp 21.

In each of the apertures I8 and I9 is disposed a tab or lamp contact gripping element 2|, constructed as shown in detail in Figure 5. In the present embodiment, each tab 2| is formed of spring metal and has a well or pocket 22 between resilient gripping elements 23 and 24 thereof. One of theconducting prongs or projecting lead members 25 and 26 of an associatedlamp 27, may be gripped between the elements 23 and 24, as shown most clearly in Figure 2. Each tab 2| also comprises a conductive flattened extension or tail 28 which may be imperforate, or apertured as indicated at 29 and/or 3|. Between a pair of said extensions 28 lying generally parallel in each socket, is disposed a quantity of material 32, the partition 33 between the apertures I8 and Hi being partially cut away for the reception of said material, as shown most clearly in Figure 2.

The material 32 may be of a type which is substantially non-conducting under normal operating conditions, but will break down and conduct when the voltage is substantially increased above the normal voltage, and again revert to a substantially non-conductive Condition when the voltage is reduced. A predetermined breakdown voltage starts across the material an are which holds until the voltage approaches zero. It is also of such construction that after breakdown it has sufficient resistance to cause a voltage drop approximating that of the lamp, thereby preven ing abnormal current from flowing in the remaining lamps of the string.

Material for such purposes desirably consists of one selected from the group consisting of manganese, manganese oxide, and compounds of manganese and silicon, which have the proper conductivity for use in the sockets for six volt lamps, adapted for a supply voltage of about 120 with 20 in a string, and silicon or silicon carbide if lamps of higher voltage are to be used. One preferred formula is to take manganese of 20 to 30 mesh which has been slightly preoxidized and moistened with a binder, selected from the group consisting of plaster of Paris and sodium silicate, to make a slurry which is run in between the pair of extensions 28 and, at the same time, performs the additional function of cementing such tabs in the socket plug [1.

It has been discovered that particles of manganese may have a high current passed therethrough to fix the amount of oxide at the points where the crystals engage one another, thereby fixing the voltage breakdown and conductivity. Such a mass, especially when the particles are fixed in relation with respect to one another, as by making a slurry such as previously described, has a given breakdown voltage while, at the same time, it will revert to a substantially non-conducting condition when the voltage is reduced sufficiently. The predetermined breakdown voltage starts an arc across the oxidized material, which are holds until the voltage approaches zero. After the material 32 has been placed, as indicated in Figure 2, the lower end of the socket may be closed by a cap 34. If such sockets are to be used for Christmas tree lighting, a bead 35 may surround the leads 36 and 31,, which extend through the cap 34 and have their ends crimped to the gripping elements 23 and 24, as indicated at 38 and 39, or otherwise electrically connected thereto. The cap 34 may be held in place in any desired manner as by cementing, or formed in accordance with one of the succeeding embodiments to be described.

The lamp 2'! which is preferably used in the socket described, may have a filament ll mounted on the inner ends of leads 42 and 43, which may be of relatively small section and project from the relatively large contact pins. The points of union between the leads and pins are desirably imbedded in a relatively flat press 44, which with the prongs 25 and 26, function as the base. The lamp is sealed, after exhaustion and/or gas filling, at the tip 45. A preferred form of lamp is described and claimed in the Way application, Serial No. 748,779, filed of even date herewith, now Patent No. 2,491,237, dated December 13,

Referring now to the embodiment of my invention illustrated in Figures 6, 7, and 8, there is shown a socket I I which may replace the sockets of the string illustrated in Figure l, or be used interchangeably with one or several of said sockets, as illustrated in Figure 1 by the fact that said sockets are of non-uniform appearance and differently designated. In the present embodiment, the socket I I is formed of plastic such as an insulating thermosetting resin of the condensing type, examples of which are phenolformaldehyde, furfural and urea-formaldehyde, and the interior portion ['1 is integral with the outer generally cylindrical portion W In other words, the complete socket casing, Hi -Il may have a pair of apertures it and w extending therethrough and restricted at the inner ends, as indicated at 46 and 51 The restricted apertures lli and ll are countersunk as indicated at 48 and 49 to guidingly receive the contact elements 25 and 26 of an associated lamp 27. In the present embodiment, each tab or lamp contact gripping element Zi is relatively short, but its resilient gripping element portions 23 and 24 may correspond with those designated 23 and 24 in Figure 5. However, instead of each having a relatively long conductive extension 28 as in Figure 5, the extension 28 in the present embodiment is relatively short, and the corresponding lead 36 or 37 as the case may be, is flattened as indicated at 5| and 52 and bent to be offset, as indicated at 53 and 54. The flattened offset portions extend parallel, like the extensions 28 in the preceding embodiment, being connected to the relatively short portions 28 of the tabs Zi as by soldering or welding indicated at 55 and 56. The partition 33 between the apertures i8 and ll-i is cut away along said flattened portions 5| and 52 and filled with a quantity of material 32 which may correspond with the material 32 of the preceding embodiment.

In the present embodiment, however, the socket portion 16*, by virtue of its construction, may be more ornate than that of the socket 15 of the preceding embodiment, in that it may be molded to the outside appearance illustrated in Figure 1. That is, it may represent wax portions 51 dripping from the top edge, as if it were a candle, and the lamp 2! the flame. Or it may be formed with the lower bead or flange portion 58 omitted, so as to have an appearance as represented by the reference character l l in Figure 1. After the material 32 has been placed as indicated in Figures 6 and 7, the lower end of the socket may be closed by a cap 3%, which may be preformed with a bead 59 cooperating with a corresponding groove 6!, sothat it will snap into place and hold the parts in the position illustrated in Figures 6 and 8.

Referring now to the embodiment illustrated in Figure 9, a construction is there disclosed which may be identical with Figures 6, 7 and 8 insofar as the casing [6 of the socket li is concerned. However, in the present embodiment the tabs 2 1 are like the tabs 2 l of the first embodiment, except that the portions 23 and 24 forming pockets 22 thereof are not crimped about the leads 36 and 31 said leads instead being passed through apertures 2.) and then back through apertures 28 as illustrated, so as to provide a tighter connection between the leads and tabs. Otherwise the construction of the socket may correspond with that of Figures 6, 7 and 8, as it may have a closure. cap

like that designated 34*, and be formed for reception thereof as in the preceding embodiment. As an alternative, however, a cap 34 as illustrated, may be employed and held in place as by a lock spring 62 fitting in a corresponding groove 63.

It will also be understood that in both the form of Figures 6, 7 and 8 and that of Figure 9, the top or cup-shaped portion of each socket is desirably formed, not only for the guidance of the pins 25 and 26 by countersinking at 48* and 49, or 48 and 49*, as the case may be, but also tapered as indicated at 63, and formed with a narrow fiattened section indicated at 64, so as to provide a guiding pocket corresponding with the shape of the base, or flattened pressed portion 44 of the lamp 21.

Although preferred embodiments of our invention have been disclosed, it will be understood that modifications may be made within the spirit and scope of the appended claims, and that we contemplate transposition of features. For example, any one of the forms of caps 34, 34 and 34*, may be used with any form of socket. Although we have shown lamps particularly adapted for use in a Christmas tree string, we do not wish to be limited to this showing. Such sockets may be used where lamps for series operation are desired, unless the voltage is not suitable for the short circuiting material disclosed. Said material, however, may be varied to accommodate different voltages.

We claim:

1. A socket for an electric lamp having contact elements, comprising tabs for connectively receiving said contact elements, leads extending from said tabs for connection to a source of power, and material which is normally substantially nonconducting disposed between said leads adjacent said tabs, said material consisting of preoxidized 20-30 mesh manganese, moistened with a binder selected from the group consisting of water-admixed plaster of Paris and sodium silicate solution to form a slurry, and cementing said tabs in the socket.

2. A socket for an electric lamp comprising an outer generally cylindrical portion, an internal portion formed with a pair of parallel apertures terminating in restrictions flared to guidingly receive contact prongs of an associated lamp, a contact tab disposed in each aperture and each tab consisting of a lamp contact prong gripping portion normally underlying a restriction and a conductive tail portion projecting toward the outer end of its receiving aperture, and material selected from the group consisting of manganese, manganese oxide, and compounds of manganese and silicon, which has the proper conductivity for a six-volt lamp so that it will break down and conduct electricity within a substantially higher range of voltage, and again revert to a substantially non-conductive condition when the voltage is reduced, said material being moistened with a binder selected from the group consisting of water-admixed plaster of Paris and sodium silicate solution to form a slurry, and cementing said tail portions in said socket, whereby the voltage across the socket when operating in a string and when the lamp is removed is approximately the same as with the lamp in the socket, because of said cementing material between said tail portions.

CLAIR MICHAEL RIVELY. HENRY W. RIMBACI-I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 319,177 Bernstein June 2, 1885 456,327 Smith July 21, 1891 481,019 Ford Aug. 16, 1892 625,395 Houston et a1 Feb. 23, 1899 1,024,495 Booth Apr. 30, 1912 1,491,340 Curtis Apr. 22, 1924 1,745,690 Pritchett Feb. 4, 1930 1,954,355 Handy Apr. 10, 1934 2,332,077 Hays -1 Oct. 19, 1934 2,072,337 Kamm Mar. 2, 1937 2,177,806 Kamm Oct. 31, 1939 2,408,124 Rolfes Sept. 24, 1946 2,431,151 Tellegen Nov. 18, 1947 FOREIGN PATENTS Number Country Date 288,988 Germany Aug. 15, 1914

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