US242137A - keith - Google Patents

Description

No Model.)

' N. S. KEITH. Electric Lamp.

IIIJII'T 11 W1 names www UNITED STATES PATENT OFFICE.

NATHANIEL S. KEITH, OF NElV YORK, N. Y., ASSIGNOR TO THE FULLER ELECTRICAL COMPANY, OF SAME PLACE.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 242,137, dated May 31, 1881.

(No model.)

To all whom ct may concern:

Be it known that I, NATHANIEL SHEPARD KEITH, of the city, county, and State of New York, have invented a new and useful linprovement in Electric Lamps; and I do hereby declare that the following; is a full and exact description of the same, reference being made to the accompanying drawing.

My invention relates to that class of electric lamps which use the volta-ic arc, and is more especially valuable as an addition to them when they are used in multiple arc '27. 0., when the current from a generator is divided among derived circuits in which are placed two or more lamps.

Heretofore the difficulty to beovercome in dividing an electric current between lamps placed in multiple are was that due to the extreme unequal resistances of the several lamps, the current, in obedience to the wcll'known laws, being divided in like unequal proportions between the lamps. These conditions have made the division of electricity between lamps of the voltaic-arc type impracticable. The remedy for these conditions is the application of a device which will automatically adjust and keep, at least approximately, the resistances of the several lamps of definite values.

In working lamps, ordinarily, when the carbons touch each other the resistances are the lowest, and when they are separated to the allowable extent the resistances are highest. It has been found practically impossible to cause the absolutely simultaneous movement of the carbons to and fro, so as to keep the resistances of the several lamps in nearly constant relation. My invention accomplishes the desideratum.

Referring to the accompanying drawing, A is a helix of insulated wire, having a resistance about equal to the normal resistance of the voltaic are of the lamp to which it is attached or with which it is associated. It may be placed in any convenient place about the lamp or in its neighborhood.

B represents several wires, which are electrically attached to places on the wire of the helix, which places represent several equal divisions of the wire.

The wire 1) represents one end of the helixwire, and the wire (t represents the other end, connected with the last strip, g.

C represents a form of insulating material, to which are attached or in which are embedded a series of parallel metallic strips, as many in number as there are loops B from the resistance-coil. To these strips are connected, scriatim, the wires B.

D is a piece of metal, of curved form on the under side, or the side which rocks on the form C.

E is a wire electrically connected with one of the binding-posts at the top of the lamp, (marked F)the negative onein this caseand with the rocker D. The binding-post F is insulated from the frame of the lamp. The other binding-post for the outside circuit is in electrical connection with the frame of the lamp and the upper carbon-holder, after a wellknown manner, so that the current entering at said post will pass to the upper or positive carbon, thence to the lower carbon.

G is a wire electrically connecting the plate g with one end of the coil of the electro-magnot H, which is a part of a lamp in use in the art. The other terminal of the eleetro-magnet is in electrical connection with the lower carbon-holder, which is insulated from the main frame of the lamp in any suitable way.

I represents an armature, which is attached to the free end of a swinging lever, havingits fulcrum at the other end, and carries the clockwork which controls the movements of the working parts of the lamp. One of the wheels of this clock-work gears with a rack upon the carbon-carrier. The clock-work is locked and released by means of a stationary yielding detent, which is engaged and disengaged with a wheel 0! the train by the movements of the armature-lever carrying said train. The construction andoperation ofthcse devices are well known in the art, and need not be further described.

Other devices may obviously be used in place of those referred to for separating the carbons and controlling the length of arc.

K is a rod which connects the swinging lever with the rocker D, so that when the lever swings the rocker is rocked upon form 1) and makes electrical connection successively with the strips and through the corresponding portions of the helix A.

L is the rod which carries the positive electrode in this case.

The operation of the arrangement is as follows: The armature I resting atits lowest point, the rocker I) rests on the first strip 0, and the carbons are in contact. The path of the current is then (entering at the post in connection with the upper carboncarrier) through the upper carbon to the lower carbon, electromagnet H, wire G, strip g, coil A, strip a, rocker D, and to binding-post F. The resistance is that of the lamp and carbons plus that of the helix A, which together is equal to that of lamp and carbons plus that of the voltaic are due to the lamp. On making the circuit the armature I is raised by the attraction of the magnet H, and it lifts the carbon-carrier L, separates the carbons, forms the voltaic are, and also rocks the rocker D onto the several strips successively, thus throwing out of circuit in regular progression the several divis ions of the coil of the helix until the rocker rests 011 the strip y, where the helix is completely out of circuit.

I do not limit myinvention to the apparatus shown, nor to the combination with the lamp shown, as it is evident that after this specification other progressively varying resistance apparatus may be applied, as well as other lamps used.

It is plain that this operation compensates for increments of resistance at that portion of the circuit called the voltaic are by decrements of resistance at another portion of the circuit-namely, the helix A. As this apparatus, then, has nearly constant resistance at all times, it becomes possible .to place several of them in multiple are for practical electric ligh ting.

Having described my invention and its operation, I hereby claim 1. The combination, with the lifting electromagnet of an electric lamp, of a resistancecoil, loops or connections therefrom at various points, and a circuit-closer operated by said electro-magnet, the whole so arranged that as the carbons are separated the divisions of the resistance-coil are successively cut out of circuit.

2. The combination, with the lifting electromagnet of an electric lamp which serves to separate the carbons to a regulated distance, oi:- a resistance-coil in the principal or direct circuit with said electro-magnet and a circuit closer which determines thenumber of coils in circuit, all so arranged that as the carbons are separated by the attraction ot'said electro-magnet the total resistance of the coil diminishes.

3. The combination, with the armature of an electro-magnct which controls the length of arc in an electric lamp, of an artificial resistance, loops or wires leading therefrom at grad uated points in said resistance, and a rocking circuit-closer connected to the armature, the whole so arranged that as the armature is attracted the rocking circuit-closer makes successive contact with the loops of said resist ance, so as to cut the divisions thereof successively out of circuit.

i. In combination with the regulating electro-magnet of an electric lamp which serves to control the length of are, a resistance at another point in the same principal circuit with the are, and circuit-closing devices controlled by said regulating elcctromagnct, the whole so arranged that the regulating electro-magnet operates the circuit-closer and diminishes the resistance simultaneously with its operation in increasing the length of-arc, substantially as and for the purpose described.

5. The combination, with theregulating electro-magnet of an electric lamp, of the resistance-helix A, wires B, form C, and rocking circuit-closer 1), operated by said electro-niagnet.

6. The combination of thelil'ting or separating electro-magnet 01' an electric'lamp with the rocker D and link K, substantially as described.

N. S. KEITH.

Witnesses:

HERMAN L. 1%. Emma, Go. H. HINNAU.

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