US613647A - Sachusetts - Google Patents

Description

N0. 6|3,647. Patented Nov. I, I898. C. W. BROWN.

INSUL'ATUR FUR INCANDESCENT ELECTRIC LAMPS.

I (Application filed Dec. 15', 1397.) (No Model.)

. E I F6 WITNEEEELE- K 4am UNITED STATES PATENT OFFICEQ CHARLES W. BROl/VN, OF BOSTON, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, OF ONE-HALF TO LAROY S. STARRETT, OF ATHOL, MAS

sAoHUsETrs.

lNSULATOR FOR INCANDESCENT- ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 613,647, dated November 1, 1898.

Application filed December 15,1897. Serial No. 661,960- (No model.)

To all whom it may concern.-

Be it known that 1, CHARLES W. BROWN, of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Insulators for Incandescent Electric Lamps, of which the following, taken in connection with the accompanying drawings, is a specification.

The object of this invention is to provide for ordinary incandescent electric lamps of the so-called Edison type an improved insulating-sleeve which shall obviate the dangers incident to the exposure of the outer portion of the metallic shell or collar (into which I 5 the neck of the bulb is set) to contact with external conducting substances. The base of this shell or collar is screw-threaded to engage with the sheet-metal screw-socket of the lamp, both of said parts beingin the electrical 2o circuit, and hence requiring to be kept free from danger of contact with other conductors. In these lamps as heretofore introduced and now largely used it is customary to surround the neck of the bulb and the collar thereon 2 5 with a short hard -rubber ring internally threaded to screw upon the outside of the sheet-metal screw-socket, and thus to insulate the conductors from the metallic bracket or wall-fixture, such ring having around its outer margin a radial flange or enlargement which bears against the adjacent surface of the porcelain reflector surrounding the lamp neck or against the outer sleeve of the bracket, so as to hold such reflector or sleeve in posi- 3 5 tion when the bulb is removed and replaced. Said ring, however, does not cover the outer portion of the shell or collar fixed on the neck of the bulb, and hence such collar is exposed to accidental metallic contacts, involving fire o risks and other dangers. My improved insulating-sleeve accomplishes perfectly both these objects and complies with recent requirements of the NationalBoard of Fire Underwriters as to such exposures.

My invention is embodied in a hard-rubber or other non-conductin g tube internally screwthreaded to engage with the threaded socket and having about mid way of its length a thickened and preferably milled annular portion or shoulder extending outwardly from its periph- 5o cry to bear against the reflector or the bracketsleeve, the tubular body extending above and below said shoulder or annular portion. By preference I make these projecting end portions about equally thin, so that either end will pass through the central opening in the reflector and enter between the bracket-sleeve and the threaded socket, making the device reversible. I provide also a supplementary washer slipped over the reduced end of the insulator, between the shoulder and the reflector, when desired.

In the drawings, Figure 1 represents a lamp provided with one of myimproved insulators, shown in longitudinal section. Figs. 2 and 3 represent the insulator in perspective and in longitudinal section, and Fig. 4 shows it provided with a supplementary ring. Fig. 5 is a modified form in which the enlargement extends to the outer end. Fig. 6 shows the supplementary ring detached.

A represents the neck of the lamp-bulb, provided with the permanently-affixed collar B, having a spiral corrugation or coarse screwthread extending about two thirds of its length.

O is the usual sheet-metal screw-socket into which the threaded end of the shell or collar B is screwed.

D is my improved insulator, internally 8o threaded to screw upon the exterior of the threaded socket O and formed midway of its length with the raised external shoulder or ring D, serving to hold the reflector E in place and as a stop to prevent screwing the insulator in too far. The outer end of the device extends beyond and effectually covers and insulates the metallic collar B, thus preventing contact of any electrical conductors therewith. The end portions being much 0 thinner than the ring D, either end may screw in between the socket O and the surrounding portion F of the metal bracket, while the other extends over the outer end of the collar B and around the lamp-neck. The 5 outer end of the insulator may be as thick as the ring D, as shown in Fig. 5; but material is saved and the appearance improved by making it as shown in the other figures. The relative dimensions of these end portions may vary so long as one of them covers the outer part of the collar B, While the other insulates the lamp from the bracket. In some cases I provide a suitable washer G, surrounding the reduced end of the insulator between the ring D and the face of the reflector. This Washer I use when the reflector is omitted or in cases where the metal shell or collar B of the lamp is of unusual length, my insulator being thus held somewhat farther out 011 the neck of the lamp.

I claim as my invention 1. The described reversible insulator formed of non-conducting material internally threaded, having about centrally a thickened peripheral ring and at either side thereof thinner end portions projecting longitudinally from and of less diameter than said ring, substantially as set forth.

2. The lamp A with fixed collar B and wallsocket C in the electric circuit, in combination with the tubular insulator D D of such length as to cover the outer portion of the collar and extend between said collar and the bracket-sleeve F, and with the supplementary Washer G adjacent to the shoulder D, substantially as set forth.

3. The incandescent lamp A with its threaded shell or collar 13, the sheet-metal screwsocket O and the bracket-sleeve F, in combination with the threaded non conducting tube D formed with the radial shoulder D adapted to support the reflector E, and with the projecting ends respectively insulating said sleeve from the socket and the outer end of said collar from external conductors, substantially as set forth.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 4th day of December, A. D. 1897.

CHARLES W. BBOVVN.

WVitnesses A. H. SPENCER, lI. -W. LADD.

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