US147487A - Improvement in duplex telegraphs - Google Patents

Description

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Duplex Telegraphs.`

- Patented Feb. 17,1874.

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MMX m wnfe Unrrnn STATES PATENT OFFICE,

yEORGES DINFREVILLE, OF NEW YORK, N. Y., ASSIGNOR OF ONE-FOURTH HIS RIGHT TO WILLIAM N. ARMSTRONG, OF SAME PLACE.

IMPROVEMENT IN DUPLEX TELEGRAPHS.

Specification forming part of Letters Patent No. 147,487, dated February 17, 1874; application filed April 25, 1873.

To all whom it may concern: l

Be it known that I, GEORGES DINFREVILLE, residing at the city of New York, in the county and State of New York, have invented a new and simple Method of Adapting Duplex Transmission to an ordinary Telegraphic Line, of which the following is a specification:

The object of this invention is to obtain a simple method of sending messages simultaneously, over the same wire, in 'opposite directions, either between terminal, or terminal and way, or wayv and way, stations. It has, for a further object, the sending of messages, as above set forth, with the least possible change of instruments and dispositions already in use; and for this purpose, and for illustration, the Morse system is herein chosen.

My invention requires the following arrangements First, in opposingto each oth er, thro ugh a telegraphic line, at its extremities, the similar poles of the terminal batteries, so that they have a common circuit, and neutralize each other, second, in using a single contact-key at each station in working the line for duplex transmission. The anvil of this key connects with the ground, while a wire from its lever `is in junction with a proper point in the wire of the helices of the main electro-magnet, the purpose of which I will describe hereafter; third, the exposing of one or more layers or parts of the helices of one spool of the main electro-magnet, so that direct contact can be made, at any desirable point in the helices, with the wire from the lever of the key; fourth, a shunt-circuit of variable and proper resistance, one extremity of which is attached to the wire connecting the key with the helices above described, the other extremity being connected, when required, with one or the other end of the wire going out of the electro-magnet, as explained hereafter.

By way of explanation, l state that, in a common circuit, when the poles of two batteries are opposed, their effects are neutralized; but, if awire connects the common circuit with the ground, two distinct circuits are at once made. Also, if one spool of a common electromagnet be traversed by an electric current, and the other spool be traversed by a current My invention consists in the combination and use of the above-mentioned opposin g batteries, electro magnets, single contactkeys, with shunt-circuit, if necessary, so that the depressingofthekeyatthesending-stationdivides the common circuit of the batteries hereinbcfore described into two independent circuitsone of the distant and receiving station, through the line and sending-station, and the other a short circuit of the battery at the sending-station, the former recording signals at the receiving-station, and both circuits neutralizing each others eects in the sending-station, so that its armature is not affected; and, also, by depressing simultaneously the keys at terminal stations, two distinct local and independent circuits are made at each station, and each station records only the signal ofthe other.

The circuit-reversers are here used in order to show how my system can be used with the common Morse plan, and the single transmitting and ordinary method used, by simply moving the circuit-reverser, and connecting the line and batteries in the usual way.

My system, when used alone on Morses plan, would connect, through wire e, the electro-magnet and battery-pole B, dispensingwith X a b el, and negative pole A would go directly to ground.

In the accompanying drawing, Fi gurel represents a plan view ot' the system, showing the arrangement for a line of three stations-two terminal and one way--all in the same circuit. The disposition is the same if more stations are used. Fig. 2 is a sectional view of the stations. Fig. 3 is a detail and end view of one coil of the main electro-magnet.

Similar letters of reference indicate corresponding parts.

The letter A represents the negative, and B the positive, pole of the main battery at terminal station O. The other terminal station, D, has the poles of its main battery represented by E for the negative, and F for the positive, pole. G is a way-station wit-hout any main battery. The poles of the batteries are connected with the arms ot' the cireuit-rcversers X and X2.

The drawing shows the line ready for duplex transmission. The circuit of the battery at station C as follows: Fro1n the positive pole B through arm a of circuit-reverser X, conductor b, anvil of common key R, (used in single transmissiom) circuit-closer d of the key lt, conductor c, helices ot' the electro-magnet lI, through line-Wire I, and, it' the eut-out g is open, as shown, at waystation G, through electro-magnetJ and circuitcloserj, (of the common key for single transmission,) conductor Z, again line l', helices otl electro-magnet at terminal station l), conductor c2, circuit-closer d2, conductor b2, and conductor c2 of circuit-closer X2, which is attached to the screw-post of the positive pole F, through battery at l), grcuiul-wire N, groundconductor N2, and other arm of circuit-reverser X, to negative pole A. Also, circuit from battery at station D is from positive pole F through a2 b2 d2 c2, lnaguet L, line l, and way-station G, n'iagnet H, wire c d b, arm a ot' circuit-reverser X, to positive pole B, through battery at c, other arm ot circuit-reverser X, conductor N2, to ground, and N to negative pole E.

lt will be noticed in the drawing that the Morse key, with circuit-closer, is shown in direct circuit in all the stations, so that, by merely changing the position ot' the circuitreverser of either terminal station, the line can be worked on the closed-circuit system tor simple transmission, as now in use, the

relay-armatures being attracted when line .is not worked.

Fig. l shows at station (il a rheostat, O, in the shunt-circuit l, connecting the battery through keys lt and M2 around the magnet H, the arm m being used to bring into circuit a greater or less amount ot' the resista-nee O. Similar dispositions are made at the other stations. At the way-stations movable arm ot' the rheostat can be brought in contact with one or the other extremity ot' the electro-magnet, as may be required, through a eommutntor or switch attached to the arm. ln the position as shown in the drawing, with. the batteries opposed and the key at rest, no current llows in theline sufficient toovercome the springs ofthe armatures, because, the circuit ot' both batteries being always closed,and the batteries being connected to the line so as to oppose each other, the currents become opposed to each other and neutralize the et'tect in the ing, ot' the electroanagnet ll', running over a part of its helices, but leaving it where wire h2 is attached to it, through h2, key M2, part of conductor N2, and returning through branch Vof circuit-reverser X to the negative pole of battery. The other current, from positive pole F at station D, being no longer opposed by current from B at station C, passes through conductors a2 b2, circuit-closer d2, conductor c2, helices of electro-magnet L, magnetizing its cores, attracting its armature, recording signal of M2, through line I, magnet at waystations, recording same signal by attracting armatures, then to and through a part of electro-magnet at station C to the junction of wire h2 with helices 5 thence throughwirc h2, through 1 key M2, conductor N2 to the ground, back to ,1 negative pole E of battery at D, through part of N, and circuit-reverser X2.A

It will be noticed tha-t the current from B, working in local circuit, and current trom F use the wire h2, key M2, and part of conductor N2, in common, from junction with the helices as far as the circuit-reverser X. The key M2 serves to conduct two currents.

Thile all the electro-magnets ot' the line have their armatures attracted bythe current from lf), the electro-magnet Il at C, the sending-station, docs not attract its armature, for it has been divided by wire h2 into two parts, which are now traveled by opposite currents of difterent intensities. Each current tends to produce a magnetic polarity different from that ot' the other. lf the two parts of the helices are so dividedA that the polarity which the strongest current, coming from the now local battery, tends to produce in goin g through the shortest part, nearly counterbalances or neutralizes the polarity which the weaker cnrrent, coming from the distant battery, tends to produce in goin through the long'er part, and in opposite direction, no appreciable magnetization will take place in the cores of the y electro-magnet, and the armature of II will not be attracted. Thus one important condition ot' duplex telegraphy is secured.

'lhe dividing ot' the helices into two parts, so that the current in one part shall neutralize properly t-he opposing current in the other part, is made by connecting the wire h2 to the exposed layers of the electro-magnet at a point which the workin g ot' the line will determine. The proper connection made when, on depressing the key at any station, its own armature is not att'ected, the other keys being at rest. Il" the key M at station l) is also depressed alone, the results are the same. lts armature is not at't'ected, but the armature ot' receiving-station is yat work.

1t thus l. tppears that by this disposition of the line and instruments, one key alone being depressed, the sending-station records its signal at the receiving-station by receiving instead ot' sending a current, and allowing the current of the receiving-station its full force in recording.

I have 'shown `the working' of the current when one key only-for instance, M2-fis depressed. The duplex transmission will now be shown. If, while the key M2 is depressed, as above described, working the distant stations, with its own at rest, the'key M at station D be now depressed, the current from positive pole F, at D ceases to pass through the line to C, because a short circuit is insta-ntly established. The current runs from positive pole F through a2 cl2 e2, through part of magnet L, back through wire 7L and N, to negative pole. As this current, moving on a short circuit, no longer runs along wire I to magnet H, the neutralization existing at H when M2 was alone depressed is destroyed, and its armature is at once attracted through the magnetization of local current at (i, made by depressed key M2.

The currents of both batteries move in local circuits, because they meet the least resistance in that way; their circuit is not broken through the line. The very slight escape of electricity in H and L to the line, from the local circuits, still oppose each other. The armature at D, which was attracted by the depressed key M2, still remains depressed, because the current from F still runs through a part of magnet L, and with increased power, because it is on a short circuit. Stations C and D are now in the same condition. It, now, key M be raised, the condition of the current .and working is again the same as when M2 alone worked. The current from pole F again runs over line to H, neutralizes currents from B, and armature of H goes back, while armature at L remains attracted, as before, by the working of key M2. Thus the working of the armature at each terminal station is dependent upon and controlled by working of the key at opposite terminal station. Although waystation G has no main battery, it sends and receives messages in the same way. If the key Pis depressed, the two currents from C and D cease to oppose each other, and go to the ground in common through key P and conductor 2, back to their respective negative poles. For it is well known that if two batteries are opposed to each other in a line, a ground-wire at any point of. the line will divide this line in two distinct circuits, each of which will operate without interfering with the other. The armature of II and of other way-stations, if any, are attracted by current from positive pole B, going to G; and armatures at D and at other way-stations, if any, are attracted by current from positive pole F, going to G. The opposite currents, meeting in the electro-magnet at G, neutralize each other, so its own n'icssagc is not recorded. The way-stations do.not require a main battery. Station G does not require a main battery to transmit to or receive from C. It uses the main battery at D for its local neutralization, exactly as D uses it, only it is at a distance. Also, G will use the main battery of C for its local neutralization when it is signaling with D; and Gr, in duplex transmission with D, will operate exactly as if was station C. This is an important part of my invention.

Thus any two stations, either terminal or way, or way and way, can perform duplex transmission. As above described, the wire h1 is connected with a point in the helices of of current from B at e, until the neutralization is as complete as possible. The small rheostat in this shunt serves to regulate its resistance according to the changes which may occurin'different parts of the circuit. This shunt itself is not new 5 but I believe it to be new to use it, as I do, in securing a neutralization of currents in the electro-magnet by drawing otf an excess of electricity.

I believe that opposing currents of batteries of the same line-circuit is not new. I believe that a key with a ground-wire is not new; but I believe to be new, and I claim as my invention, and desire to secure by Letters Patentl. The method of duplex telegraphin g, substantially as described, by localizing or shortcircuiting the main battery at the sending-stai tion, thereby preservnig the magnetic equilibrium in the slgnahng-instrument of that station, and allowing the battery of the recein'ng-station to there exert its full force in recording or indicating signals, substantially as herein described.

2. In combination with a normally-closed telegraphic line having main batteries, one at each terminal, connected to the line in opposition to each other, open-circuit single contact-keys M M2 and branch circuits NN 2, connected to the relay-magnets at a suitable point, the closing of the said keys short-circuiting or localizing the battery ofthe sending-station through the proper `proportion of the coils of the relay, substantially as set forth.

3. In combination with a relay-magnet having its layers exposed for connection to key, and for approximate adjustment, as described, the shunt-circuit Maud rheostat c, substantially as and for the purposes s et forth.

4. In combination with the normally-closed line, having the branch circuits 7L h2 and opencircuit single contact-keys, and opposed batteries, as described, the battery-reversers and closed-circuit keys, substantially as set forth.

5.- The combination, at an intermediate or Way station, With the main line of a duplex telegraph, ofthe open-circuit keyP and branch' as described.

circuit i, connected to the relay between the terminals, the depressing` of the key closing independent circuits for both terminal batteries, giving signals to both sides of the Waystation in single transmission, or forming a duplex line with one terminal, substantially GEORGES DINFREVILLE. Witnesses W. N. ARMSTRONG,

WM. R. LEARN.

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