US771988A - Incandescent electric lamp. - Google Patents

Description

PATENTED OCT. ll, 1904.

J. R. LOVEJOY.

- NGANDESCENT ELECTRIC LAMP.

APPLICATION FILED DEO. l1, 1901.

N0 MODEL.

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UNITED vSTATI-3s Patented October 11, 1904.

APATENT OFFICE.

JESSE R. IJOVEJOY, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OE NEW YORK.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 771,988, dated October 11, 1904.

-Application filed-December 1l, 1901. Serial No. 85,478. (No model.)

To @ZZ whom t may con/cern:

Be it known lthat I, Jnssn R. LovnJoY, a

citizen of the United States, residing at Schenectady, county of Schenectady, State of New YorlLhave invented certain new and useful Improvements in Incandescent Electric Lamps, of which the following is a specification.

Much annoyance is occasioned by the burning out or rupture of laments of incandescent lamps when such lamps are arranged several in series across railway or other circuits. For example, in street-cars it is common to use one or more groups of five each, connected f from trolley to ground. Evidently the rupture or burning out of one filament puts out the whole group, and if but one group is installed the car is left in total darkness until the conductor replaces a fresh lamp. It is the object of my invention to mitigate this annoyance by arranging a lamp provided with a double filament, so that a new filamentV may be cutin, and thus restore the illumination of the car by a simple manipulation of the lamp. Again, many consumers desire a lamp for use in bedrooms, sick-rooms, &c., which may be burned with very low candle-power or full brilliancy at will. My invention lends itself with equal advantage to such use.

In carrying out my invention I proceed by providing the lamp with two filaments and three terminals, one of which terminals is the metallic shell or screw base if it be an Edison type of lamp, and the other two terminals are insulated metallic contacts mounted on the under side of the lamp-base. The two filaments may be of equal or unequal resistance,-

accordingly as it is desired to employ the lamp for car illumination, as above referred to, or for domestic purposes for night use. I provide also a socket-plug, which may be called a transfer-plug, by which current may be led from the terminals in the receiving-socket, mounted on the roof of the car or on the wall of a residence, to either of the two filaments. The plug is so organized that a common conducting-shell acts as a carrier or connector between the shell-contact of the receiving-socket and the shell of the lamp-base. It has also an insulated center-pin to connect at one end with the tongue terminal of the socket and at the other end by an elastic contact having a .contact-face eccentric to the axis of the transfer-plug with either of the insulated lampcontacts. The insulated contacts of the lampvbase may be shifted alternately into engagement with the elastic contact of the transferplug, thereby lighting up either filament at will. If thelamp by reason of a break of one `filament becomes extinguished, the other fila- `ment may be cut into circuit by a simple rotation of the lamp on its axis, and if when used as anight-lamp it be desired to cut down the illumination the bulb is partially rotated, so as to cut in the filament of lower candlepower. rIhe transfer-plug consists of a simple shell, which is slightly larger in diameter at one end than at the other, adapted to screw into the receiving-socket at one end and at the other end to receive the lamp-base.

The several features of novelty will be more fully hereinafter described, and will be detinitely indicated in the claims appended to this specification.

In the accompanying drawings, which illustrate my invention, Figure l is a sectional view of a lamp, a transfer-plug, and socket;

and Fig. 2 a detail view of the transfer-plug.

designed for use with the Edison lamp, the

plug-shell may be a single-threaded shell slightly contracted at one end, as indicated in Fig. 2, and provided with a plug of insulating material 2, such as porcelain, plaster-ofparis, or other suitable compound, through the center of which passes a conducting-pin 3, terminating in the elastic contact 4, the engaging face of which is off center with respect to the axis of the plug. This contact may be fixed to the post or may be mounted so as to be clamped by a nut, as indicated in Fig. 2, permitting its adjustment to different angular positions.

The lamp is provided with a double lilament 5 5, one pair of terminals of which lead out through a wire 6 to the threaded shell 7 on the lamp-base, the other ends of the iilaments leading through sealed-in wires, as usual, to separate insulated contacts 8 8, secured in the cement or porcelain which fastens the neck of the lamp to its base. These contacts are symmetrically placed with respect to the lamp-axis and both off center, the distance being gaged so that when the lamp is screwed into the transfer-plug the contacts will cross the face of the spring 4 and make contact therewith.

9 represents a familiar type of socket largely in use on trolley-cars and is shown as connected up with a pair of leads in the trolleycircuit. The socket contains screw connections with the leads, putting them in communication, respectively, with a threaded metal shell 10 and a metal center-pin 11. rIhus when the transfer-plug is screwed into the socket the former extends the contact from the screw-shell in the socket to the shell of the lamp-base and from the contact-pin in the socket to one of the insulated contacts on the lamp-base.

In the position shown in Fig. 1 the iilament 5 is receiving current. sirable or necessary to cut in the other lilament a partial rotation of the lamp on its axis breaks connection between the contact-spring 4 and contact 8L and effects connection with contact 8. This may be done by a quick movement, which will prevent damage from arcing. The spring 4 should be given a sufcient range of elasticity to permit of such adjustment; but, if preferred, it may be made quite stiftand shifted angularly in position to effect a new contact.

It is evident that for car use the conductor is not obliged to carry an extra supply of lamps, since in case of extinguishment of the lights through fracture or burning out of a iilament it is only necessary for him to turn In case it becomes dethe bulb to restore the lights. It will further be evident that no changes in the wiring of the car are required. The same advantage would also inhere in the application to domestic illumination. 1

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is-- 1. The combination with a double-filament' lamp having a shell-contact to which both filaments are connected and two eccentricallypositioned insulated contacts on the end of its base for the respective filaments, of a separable transfer-plug to engage a standard socket, said plug extending the shell-contact of the socket to the shell-contact of the lamp-base, and having a contact mounted eccentrically to engage either contact on the base according' to their angular position.

2. The combination with a double-filament lamp having a shell-contact to which both filaments are connected and insulated end contacts for the respective iilaments set a like distance from the lamp-axis, of a separable transfer-plug having a shell-contact and a springcontact in position to intercept either lampcontact according to their angular position.

3. The combination with a double-filament lamp having a threaded metal base and two insulated contacts for the respective ilaments mounted eccentrically by a like distance, of a separable transfer-plug comprising a threaded shell to connect interiorly with the socket at one end, and exteriorly with the lamp-base at the other, and a spring-contact to transfer the center contact of the socket to either filamentcontact by rotating the lamp-bulb.

In witness whereof I have hereunto set my hand this 10th day of December, 1901.

JESSE R. LOVEJ OY.

Witnesses:

BENJAMIN B. HULL, HELEN ORFoRD.

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