US2640969A - Lamp socket - Google Patents

Description

W. J. COYLE June 2, 1953 LAMP SOCKET Filed March 29, 1949 l I m m -i WIB 7A f//l ,/7/////Z V//. all M i June 2, 1953 w. J. coYLE LAMP SOCKET Filed March 29, 1949 4 f 52 30 38 la 58 4 7 7%/ 36 3246 I4 347/ 5?. 4a 45 7h 4e 46 le -44 60 ITI. H3222! 2O 2c,

W lLLlAM J. CovLE Patented June 2, 1953 SOCKET VVilljam Coyle, Waltham, Mass., assigner to United-Carr Fastener Corporation, Qonihridse. Mass., a. corporation of Massachusetts Application March 2:9, 1949,.Se1'ia1 No. vdigiti?" 3 Claims.

electric lamps, and has particular reference to a socket. adapted to receive a lamp. traviesa thread.- ed base.

Electrical, lamps of this type are 'commonly provided with a cylindrical base formed oi Sheet, metal, having threads rolled or stamped. into Ythe periphery, t enableY thebese to be. Screwedinto e Socket. The base-engaging portion oi the Socket iS also commonly formed oi' a. cylindrical piece 0f kSheet metal., having threads disposed. therein to cooperate with the threads on thebase.

During mass production manufacture of 'both the socket and the base, it is impractical to maintain close dimensional tolerances of the sheet members, and consequently the base and socket are subject to small but significant variations in diameter. Such lvariations are undesirable, since when a slightly undersiaed base. is. screwed into a slightly oversized socket, not. only is a poor electrical connection obtained, but. the base may fit so loosely inthe socketthat vibration and handiing during use will cause the` connection to be completely broken. This difnculty is more pro.- nounced with the smaller sizes of lamps, vand is particularly objectionable where severalV lamps are connected in series, Vin which case loosening of one ttml? in its socket will break the conoce-.- tion to all the other lamps.

The obiect of the invention .is to provide a socket having lmeans Ytherein ,for resiliently enegaging a threaded lamp base, in which said vengaging means is expandable to accommodate lampbases having small but appreciable diierences in diameter.

A further object of the invention is to provide a socket for engaging a threaded lamp base, in which the socket is provided with resilient threadengaging means and resilient base-engaging means adapted to force an assembled base into engagement with the thread-engaging means.

A still further object of the invention is to provide a socket for receiving a threaded base, in which the socket is provided with resilient arms adapted to engage the base and the threads thereon.

Other objects 4of the invention will, in part, be obvious, and will, in part, appear hereinafter. For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description, taken in conjunction with the accompanying drawing, in which:

Fig. 1 is a perspective view of the socket in which portion of the socket body is broken away to show the arrangement of the base-engaging member disposed therein;

Fie. 2 is a View in elevation. Partly via section. or the socket illustraties the, means ier retaining the oase-encadre member in the. toolset. body;-

Figore 3 is. a view in section taken eo line 3-3 of Fig. 2;

Fie.7 4 is e view in section taken on line @f3 of Fie.. also .showing a section of an inserted lamp. base;

. Fiel 5 iS enlarged View et the lower portieri 0f the heee-engaging rncmlreri Showing details. of. construction of the center connection; andy Fig. 6 is a view in elevation, partlyin section, cf the socket-and en. assembled 1eme bese- Referring to lthe drawing, there isillllstrated a lomo Socket it. which. is. adapted to receive and make electrical connection with a. lamp. 12,01 the type. which. has a sheety metal contact base l4-hav.-` ing socket-engaging threads IAS,l and a. eenter (1m1- tact member I8 disposed on the end. of. the bese .The socket lll comprises a Substantially eylinf drical hollow socket bedr 20 and a base-engaging Contact memlocr'tz. The ksocket. body 20., which is preferably formed of molded.v plastic, is provided with a pair of internal Shoulders 24. and a base 26 at, one endet 'the body having an internal openine 28 for receiving electrical lead wires 3.0.., The base-engaging contact. member 22 comprises a lease plate 32 and. a pair of.' base-engaging contact` arms 34 and it extending upwardly therefrom. The base plate 32 is provided with a eentral opening v38 having an insulating bushing 40 and a lrivet 42 disposed therein, for attaching a center contact member 44. The corners of the base 32 are turned upwardly to form prongs 46 to engage the socket body, and retain the contact member in the socket.

The contact arms 34 and 36 are shaped and arranged to be supported laterally by the body 20 when a lamp is assembled therein and are provided with shoulders 41 to rest on the internal body shoulders 24. To vallow the threaded base I4 to be screwed into engagement in the socket, the contact arm 434 is provided with a number of thread-engaging prongs 48, vertically spaced to correspond to the pitch of the threads i6 of the base. In the preferred embodiment, the prongs 48 extend inwardly and then outwardly forming a convex thread-engaging portion 50 and a free end portion 52, which is disposed for support by the socket body 20 when the base is assembled in the socket. The contact arm 36 is provided with a plate 54 having a base-engaging surface 56. In the preferred form, the plate 54 is curved to conform to the shape of the socket body 20, but has a radius of curvature greater than that? Qf. tEhe body, so that the plate contacts the body only at the outer edges. This provides a space 58 between the plate and the body, into which the plate is free to expand during insertion of a lamp base.

The dimensions of the contact member 22 are such that the insertion of the base I4 causes outward flexing of the plate 54, thereby forcing the base into engagement with the prongs '48, and causing a frictional drag between the contact arms and the base, to resist rotation of the base in the socket.

The prongs 48, by virtue of their convex shape, also have a. degree of flexibility, to resiliently engage the base I4.

By reason of the resilience of the plate and prongs, the socket is able to accommodate lamp bases which are slightly undersize or oversize, since the flexing of the plate and lprongs by insertion of the base insure that the base is firmly held in the socket. The socket may be provided with several contact arms having prongs and plate, how-ever, by provision of only one set of thread-engaging prongs, insertion of the base into the socket is facilitated, since with this arrangement, it is impossible to start the base into the socket cross-threaded.

Since certain obvious modications may be made in the device without departing from the scope of the invention, it is intended that all matter contained herein be interpreted in an illustrated and not in a limiting sense.

I claim:

1. A socket for electric lamps and similar devices having a threaded-connecting base, the socket comprising: a hollow socket body of insulating material having an outer tubular wall portion with a base receiving opening at one end, an inner tubular wall portion, radially inwardly extending shoulders between said inner and outer tubular wall portion, Vand an apertured end Wall at the opposite end of said inner tubular wall portion, and a substantially U-shaped base engaging member disposed in said body, formed from conducting material and comprising a bight portion and opposed leg portions, said bight portion having ypointed prongs, intermediate said leg portions extending angularly in the same general direction as said leg portions in biting engagement with the walls of said inner tubular wall portion to prevent axial withdrawal of Said base engaging member from said body, said leg portions including shoulder portions in engagement with the inwardly extending shoulders of said body to limit axial movement of said base engaging member upon insertion into said body, one of said leg portions having at its outer free end threaded base engaging ngers extending circumferentially adjacent the walls of said outer tubular portion for engaging such a-base between the threads thereof, and the other of said leg portions having at its outer free end a resilient curved Aplate 'portion with its side edges in engagement with the walls of said outer tubular wall portion and with the portion thereof intermediate said side edges dis-posed in spaced 'relation to the side walls of said outer tubular wall portion on an arc with a radius greater than that of the walls of said outer tubular wall portion to provide resilient means for engaging such a base and urging it into engagement with said thread engaging fingers.

2. A socket in accordance with claim 1 wherein the side edges of the plate portions are taperedv inwardly adjacent the shoulder in the leg portion to facilitate insertion of the base engaging member into the body member.

3. A socket in accordance with claim 2 having contact means secured to the bight portion of the base engaging member but insulated therefrom providing a resilient contact member disposed f between the leg portions of the base engaging member and having separate connecting wiresl extending from said bight portion and said contact through the apertured end wall of the body member.

WILLIAM J. COYLE.

References Cited in the me of this patent UNITED STATES PATENTS Number Name Date 955,438 Russell Apr. 19, 1910 1,106,974 Rush Aug. 11, 1914 1,721,566 Lofgren July 23, 1929 1,771,002 Staples July 22, 1930 1,790,239 Lawson Jan. 27, 1931 1,820,261 White Aug. 25, 1931 1,907,422 Long May 2, 1933 1,971,201 Sadacca Aug. 21, 1934 2,158,655 Frank May 16, 1939 2,283,934 Jorgensen May 26, 1942 2,284,745 Kelman June 2, 1942

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