US863617A - Combined telephone receiver and transmitter. - Google Patents

Description

PATENTED AUG. 20, 1907.

' R. I. LUDLOW.

COMBINED TELEPHONE RECEIVER AND TRANSMITTER.

APPLICATION FILED APB..6,1904.

2 SHEE S-SHEET 1.

7 0 9 1 2 G U A D E T N E T A P W 0 L D U L R E COMBINED TELEPHONE RECEIVER AND TRANSMITTER.

2 SHEETS-SHEET 2.

Finuenfoz APPLICATION TILED APR.6,1904.

WIN

from drcow warmam I 67 9 %/@M UNITED sTA ss RODNEY r.

PATENT OFFICE.

LUDLOW, OF PHILADELPHIA, PENNSYLVANIA.

COMBINED TELEPHONE RECEIVER AND TRANSMITTER.

Specification of Letters Patent.

Patented Aug. 20, 1907.

Application filed April 6,1904. Serial No. 201,794.

. To all whom it may concern:

My invention relates generally to telephone appara-.

tus and specifically to the transmitting and receiving apparatus therefor, the primary object of my invention being to unite in a single construction or device, employing a single diaphragm or elastic sound-transmitter, means whereby the telephonic conversations may be both received and transmitted.

In carrying out this primary purpose, my invention has for its objects to mechanically and electrically unite in a single instrument receiving and transmitting means which shall be mutually helpful in order that the transmitting mechanism shall increase thesound-producing effect of the received currents in the receiving mechanism; also that the receiving mechanism shall operate to increase the telephonic current given out by the transmitting mechanism; also that the elements shall be so combined that a portion of the necessary mechanical structure for one shall serve also for the corre sponding structure of the other, resulting in a less number of parts and a more compact single device than would otherwise be the case if separate and distinct receiving and transmitting instruments were merely aggregated in a single casing.

The advantages resulting from my invention will be hereinafter briefly referred to, but among those which may now be stated are, the economy in first cost resulting from consolidating a receiver and a trans mitter in a single device; and the great advantage to the operator in using it as a receiving instrument, in being able to hear the message transmitted without manually bringing the diaphragm holder to or against the ear.

To these ends my invention consists in the combination in one instrument, of a single diaphragm under tension, with means hereinafter described, operating to conduct electrically-induced sound waves thereto and therefrom, respectively; the primary identifying fea tures of such means comprising a suitably constructed casing and, within the same, concentric electro-magnetic and electric sound-transforming devices, a diaphragm common to both and arranged exterior to their electric circuits, a variable resistance conductor in series with the windings of the magnet, with means common to the magnet and'the resistance, and initially actuated by the vibrations of the diaphragm, operating to automatically vary the magnetism of the former and alter the resistance of the latter. These novel features together with the several minor combinations of elements, hereinafter described and constituting the invention in its best and preferred form, will be pointed out in the claims.

In the drawings illustrating inv invcntion:Figure l is a sectional view through tlncenter of my instrument as taken on the line 11 Fig. 3. Fig. 2 is a section at right angles to Fig. 1 with the mouthpiece and diaphragm removed. Fig. 3 is a plan view of Fig. 2

with the mouthpiece and diaphragm removed, to show more clearly the construction and arrangement of the remaining elements. Fig. 4 is a sectional view of a modified form of the device, with the mouthpiece and diaphragm removed. Fig. 5 is a detail section showing electrical connections.

Similar letters ofreference indicate corresponding parts in the figures.

Referring to the drawings. A designates an annular ring having projecting flanges a a on either side of and of larger inside diameter than the aperture a at the center. These flanges are threaded for attachment to corresponding threaded annular parts upon the main part of the case B and the mouthpiece C respectively. The portion of the mouthpiece O fitting within the part A is provided on the side toward A with two concentric annular depressions c c and a central aperture 0. Depression c is of larger diameter than the aperture a and depression 0 is of diameter equal to that of a. Aperture c communicates with the mouthpieceand is of diameter smaller than a. Glamped between A and G and lying within aperture 0 is a diaphragm D of any material susceptible to magnetism. Upon the back or reverse end of the main part B is placed a cap E closing central chamber b. This chamber communicates with the main front cylindrical compartment 12 through aperture 6 Within the compartment B is located a magnet G energizing the pole pieces 9 g about which are windings g g. These windings are so connected that the same current passes through both and tends to increase the magnetism in one at the same time that it decreases the magnetism in the other.

ner usual to magnetic receivers.

Between the poles of the magnet is placed the transmitting mechanism which in the form illustrated in Figs. 1, 2 and 3 is constructed as follows:Upon the casing of B within compartment B is provided 3. lug H split at h and pierced by pin h. Upon this pin is pivot'ed the forked arm J of any material having sufficient spring, one of whose projecting ends j rests against the diaphragm preferably at or near the center. The other end j thereof rests upon the top of the rod K. This rod passes through the aperture b and upon its rear end within the forward part of recess b carries an electrode L secured thereto by any suitable means as by nuts is k.

In the rear end of the rear recess b is another electrod'e L held in place in the manner to be described oiin any suitable manner and resting against the cap E.

The magnets are placed in' proximity to the diaphragm and act upon it in the manaffected by the same diaphragm.

Between the electrodes L and L is a spring M of general spiral form which tends to separate these electrodes and to prevent packing of the divided carbon or other suitable resistance-varying medium N. The chamber b may be provided with a lining 0 if desired. A conductor from electrode L leads up through the passageway P to finding post Q from which outside connections are made as desired.

Between the ends of magnet G lies the switch R provided with contact blades 1' r and pivoted upon binding post S. It is connected in any suitable manner to permit signaling when in the position shown in Fig. 3. When at the extreme of its motion from that shown it makes connection between binding posts '1 and U, to which one end of the magnet winding and the rod K are respectively electrically connected, thus throwing the electric and electro-magnctic circuits, in other words, i to receiving and transmitting mechanisms into series connection. The other end of the magnet winding is connected through binding post V to the outside circuit in any suitable manner, the external connections being made with binding posts S, V and Q through the openings W. a

In the form shown in Fig. 4 the fork arm I is omitted and therod K is extended to make contact with the diaphragm. In this case also the spiral spring is located within the larger forward compartment b instead of b and is made to separate the electrodes by pressure against the body of B at one end and a disk X upon rod K at the other.

The mode of operation of mydevice is as follows:- When it is desired to use the transmitter and receiver, the switch R is turned so as to join electrically binding posts T and U, to which the rod K and winding g g 'are connected, placing the magnet coils in series with the variable resistance conductor. Both are then Pulsations of current passing through the magnet coils attracting and, repelling the diaphragm with varying strengths will also pass through the variable resistance conductor but with little direct efiectupon it. The current from thecommon or local battery also passes through these series connections and varies with direct effect upon the magnet coils according to the variation of resistance in the circuit. All of the change of resistance occurs in the variable conductor and is due to variations in pressure upon it transmitted from the vibrating diaphragm through rod K due to the voice or magnetic fluctuations and results in a change of current through the magnet coils. The cause of this vibration may be either sound vibrations or these electricalvibrations resulting in fluctuations of magnetism.

It will thus be seen that if the current from the battery be in the proper direction anyattraction of the diaphragm due to an increase of current passing through the magnet coil will cause the diaphragm to press upon the-rod K causing a reduction of the resistance of the variable conductor and a further increase of current strength in the magnet coils and still further attraction of the diaphragm until a position of -equilibrium is reached between the increasing magnetism and the more rapidly increasing resistance of the diaphragm to distortion. Since this increase of magnetism due to the joint action of battery and'received currents is automatic in adjustment and instant in its action there will result-an increase in the volume of sound from this instrument when used as a receiver over that produced by an equal received current in a receiver having corresponding mechanical and magnetic dimensions. As a transmitter, likewise, greater variations in resistance and hence stronger current will be caused by the same volume of sound by reason of the action of the magnet whose magnetism is increased by increased current through its coils and vice versa on account of the series arrangement before stated. As the diaphragm approaches the magnet due to a sound wave in that direction tlie battery current is increased. It flows through the magnet coils still further moving the diaphragm and intensifying the current. Hence the receiving and transmitting mechanisms, in conjunction with the diaphragm common to both and constructed and combined therewith and with each other as described, co-act both mechanically and electrically in the manner stated, resulting in increasing the intensity and volume of sound waves in respect of the receiving mechanism,

Having thus described my invention,v what I claim as new, and desire to secure by Letters Patent, is:

1. in a telephone, a combined receiver and transmitter comprising a suitable casing, concentrically arranged electr0-magnetic and electric sound-transforming devices, a sin gle diaphragm common to both and arranged exterior to their electric circuits, with means to conduct electricallyinduced sound waves to and from said diaphragm, said llll'ElHS comprising a variable resistance.conduct'or in series with theiwindings of the magnet, and mechanism contacting with the diaphragm and operating to directly transmit its vibrations to theresistance-conductor.

2. In a telephone, a combined receiver and transmitter, comprising a suitable casing, with concentric electro-magnetic and electric sound-transforming devices, a single diaphragm common to both and arranged exterior to their electric circuits, a variable resistance conductor in series with the windings of the magnet, a pair of separated electrodes, and connecting contact means between the diaphragm and one of said electrodes, whereby on the pulsation of the diaphragm by'rcceivcd currents, the magnetic current is automatically increased by a reduction in the resistance of the variable conductor.

3. In a telephone, a combined receiver and transmitter comprising a suitable casing divided into'compartments, with concentric electromagnetic and electric'sound-transforming devices, a single diaphragm common to both and located outside their electric circuits, 8. bi-polar magnet in one of said compartments, a variable resistance conductor between connected windings on the poles of the magnet, and mechanism between the diaphragm and the variable resistance conductor whereby the resistance and the magnetism are mutually varied by automatic operation of the transmitting me'ch'anism brought into action by the pulsations of the diaphragm due to receivedcurrents.

4. In a telephone, a combined receiver and transmitter 7 comprising a casing containing two compartments, an elec-' sistance conductor in series with the windingsthereoff, a

containing casing therefor comprising two compartments, one of them containing the magnet beldw the diaphragm and the other of them containing the resistance conductor below the magnet, 21 pair of electrodes in the same compartment and on. either side or the resistance conductor, and means connecting one of said electrodes with the diaphragm whereby the resistance conductor is directly varied by the pulsations of the diaphragm.

6. In a telephone having a combinedreceiver and transmitter with a single diaphragm exterior to the electric circuits, an electro magnet, a variable resistance in series with the windings thereof, with means common to the magnet andvresistance, but exterior to their electric circuits, operating to automatically vary the magnetism of the former and to alter the resistance of the latter.

7. In a telephone a combined receiver and transmitter comprising an electro-magnet, a carbon resistance in series with the winding thereof, a diaphragm, and a pivoted 1O elastic arm between the resistance and the diaphragm operating to transmit pulsations between them.

In testimony whereof, I have hereunto alfixed my signature this fourth day of April A. D. 1904.

RODNEY F. LUDLOW. Witnesses:

CHAS. W. MILLER, Emma E. SCHWARTZ.

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