US266021A - Telephone - Google Patents

Description

(No Model.)

T. A. EDISON.

TBLEHONE.

Patented Got. 17, 1882.'

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THOMAS A. EDISON, OF MENLO PARK, NEWT JERSEY.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 266,021, dated october 17, 1882.

Application led October i7, 1881. (No model.) Patented in England June 15, 1878, No. 2,396.

1o all whom it may concern Be it known that I, THOMAS ALVA EDISON, of Menlo Park, in the State of New Jersey, have invented an Improvement in Telephones, (Gase No. 158%) ot' which the following is a specification.

This application is a division of my application No. 158, filed November 11, 1878; andthe said division is made for the purpose of separating from said original application matters that are notin interference, and for separating the different features ot' invention into two additional applications. The present I term Case No. 158A. Letters Patent in Great Britain, No. 2,396, show the present device. The same was applied for June 15, 1878; but the specitication was not tiled until December 13,1878.

The object of this invention is to transmit oral com municationsover electric circuits and said invention consists in devices for transmitting positive and negative currents by varying the resistance in the telephonie transmitter, in combinationwith a heatstone balance.

Thetransniitting-instrument,containingcarbon or similar material in the circuit, is also peculiarly constructed, and the diai'ihragm of the rcceiving-instrument is acted upon by an indnctorium.

In the drawings, Figure l represents the transmittirig-instrument sectionally, and also shows the circuit -connections by a diagram. Fig. 2 represents the circuit-connections in a slightly-moditied form, and Fig. 3 is asection in larger size through thescI-ew and circuitregulator.

The transmitting-instrument A contains the mouth-piece b and a diaphragm, lc, secured at its edges. The center ofthe diaphragm is platinized, and upon this rests a button, c, of linely-divided conducting material, such as inetallized charcoal, lamp-black, or iodide of copper. The metallic plate d is kept in contact with the button by the spring c, and e is an adjusting-screw to regulate the pressure of the spring against the plate l and button c. Said screw passes through the metallic support that is secured to the vulcanite ring g around the button c. The rod thatis attached to the plate d passes freely into au axial hole in the screw c', so as to be guided thereby, but allow the screw to be set up to regulate the spring without the screwactingdircctly 011 the plate d. The diaphragm is connected to the wire 4 and the plated to the wire 5. The button, of carbon or other similar material, bccomes a circuitregulating device to control the electric condition of theline and cause the same to vary in a mannercorrespondingtothe sound-waves that act upon the diaphragm, as set forth in applications heretofore made by me. The ring g and circuit-regulatingdevices are upon the diaphragm It', and hence move with it; but any atmospheric vibrations acting on the diaphragm 7c produce a variation in the resistance ofthe carbon or similar button, c, in the electric circuit, in consequence ofthe difference in 'pressure upon such carbon button,resulting from the tremulous movement of 7o the parts and the inertia of the plate d. The carbon or similar material and the metallic surfaces in contact therewith become the electrodes ofthe electric circuit. The transmitter A isin one branch of the Wheatstone bridge,

R3 being a resistance equal to that ofA when f not subjected to sonorous vibrations. It and E2 form the other sides of the balance and have equal resistances. The bridge-wire from M to N is contained in the electric circuit that extends from N by the line wire to thc distant receiver H, thence to the earth, and returning to the earth-plate at the transmitting-station and to M. The battery B, of several' cells, is between 5 and It 1?. When the resistance ot'A R2 is equal to that of It R3 no current circulates upon the line. When sono rous vibrations vary thcresistance ofthe carbon button c in A the current will pass upon the line in one direction or the other. When `the resistance of A is increased the current passes in one direction. Then it is lessened the current passes in the other direction in consequence of the balance being disturbed. The induction-coil H has its secondary coil included in the line-circuit, and the primary coil is connected with a transmitting-instrument, T, constructed and operating in a similar manner to thetransmitter A, the local battery B being in the circuit through the carbon button and primary coil. The receivinginstrument L is provided with a diaphragm,

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that is acted upon by the core ot the inductioncoil H, and hence the induction-coilis utilized,

. and serves for receiving or transmitting telephonically.

In Fig. 2 the balance of the similar batteries, B B', with opposite poles to line,=is obtained by the rheostat R3, that is ot' a resistance equal to that ot the instrument A-When at rest, and when the resistance of the carbon button in A is increased or decreased by the sonorous vibrations the current will pass upon the line, either positive ornegative, according to the resistance in A.

In my application No.130 the diaphragm is in direct contact with a surface of plumbago or similar material, and in my application No.

`151, patented April 30, 1878, No. 203,016, a

v n e ies, a system of balanced circuits, a telephonie transmitter constituting a variable resistance in one of the balanced circuits,anda telephonie receiver in the bridge-Wire of the balance, substantiailyV as set forth.

3. The combination, in a telephone, ofcarbon or similar material,forming acircuit-regulator, a diaphragm, and a holder upon and entirely supported by the diaphragm, and arranged to resist the movement ot' the diaphragm and circuit-regulator, substantially as set forth.

4. Inaspeaking-telephone, thecoinbination, with the diaphragm, ot'earbon or equivalent material in the electric circuit, and a spring or yielding presser to apply an initial pressure to the carbon, and means for supporting both the carbon and presser upon the diaphragm, substantially as set forth.

5. In a speaking-telephone, the combination, with the diaphragm, ot' carbon or similar material, a spring pressing upon the carbon, and

means for adjusting the pressure and supports therefor upon the diaphragm, substantially as Set forth.

Signed by me this 7th day of September, A. D. 1881.

THOMAS A. EDISON.

Witnesses:

GEO. T PINCKNEY, HAROLD SERRELL.

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