US1445233A - Telegraph system - Google Patents

Description

H. W. O'NEILL.

Feb. 113, 1923. A 1,445,233.

TELEGRAPH SYSTEM.

FILED Nov. 19. 1919.

/n yeh for; Hen/y MZ 'A/e/V/ Patented Feb. i3, 1923.

HENRYW. ofNEinnon BROOKLYN, Nnw YORK, a'ssicfmin` To WESTERN unicornio COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION '0F YORK. i

i ATELEIGnMSNPIE SYSTEM.

Application led November 19, 1919. Serial No. 339,093.'

To all whom t may concern: Be it known that I, HENRY W. ONEILL, a

citizen of the United States, residing at In signaling over conductors of high electrostaticl capacity, such as submarine cables, the time required for the transmissionof a given number of impulses will vary almost directly in proportion to the capacity and resistanceof the line circuit.

The resistance and inductance of terminal apparatus, the time constant of operation of relays or other receiving devices and the potential and manner of applying transmission currents to a line conductor are all factors which play a part in affecting the rate of transmission or the degree of efficiency at which a signaling circuit may be operated. lt is common practice to so proportion the various parts of a signaling circuit and the potentials of the currents employed, that following an application of current at the sending end of a line the receiving devices at the distant end will respond on the in stant `the potential of the circuit reaches a strength equal to approximately two-thirds of the final or steady current value possible after the current has becomev equalized in the circuit. The current in excess of twothirds of a final steady potential value in a line circuit represents the factor of safety.

rllhe greater the inductance or the more eflicient the magnetic circuit of a relay the higher the time constant of its operation, and in relays of commonly accepted design the efficiency of the magnetic circuit is appreciably increased vwhen the armature' is in its attracted position. In case the relay is subjected to an energizingv current of maximum potential for other than `relatively short periods, the increased density ofthe magnetism. created therein `will cause a slow release of the arnfiatureonl cessation of the. energizing current.

From the foregoing it will be clear that continuation of current. beyond the point where it has attained its full or steady current value in a signalingeircuit necessarily results in an excessive charging -of the line conductor proper andlalso in the setting up of unnecessarily high density in the magnetic circuits of the relays or other terminal equipment. `These conditions accordingly result accumulatively in reducing Ithe speed l,

atwhich signals .may kbe transmitted` over a j The increasing employment. of underground and` aerial cables necessary in the joining up of'land lines, results inv placing such lines relatively' in the category of cable circuits. Therefore, as will presentlyv appear the present invention may alsobe employed to advantage von such' land circuits.

The foregoing observationsmalre it' clear that for a circuit in which the electrical characteristics of the vterminali.apparatus andthe line conductor bear a proper relation, a relatively highpotential current may i be applied to the line and that following thejinstant when thecurrent reaches its i steady value,'the potential may be reduced advantageously. .v This reduction of the cur-` rent strength may take placeconsiderably in advance of the expiration of a period have been operated the polarity 0f the current of low potentiall should bathe same as the polarity of the high potential current for which it may have been` substituted.

For convenience, the high potentialA currents may be referred to as crontrol7 cur rentsvor currents at control/potential, while the low potential .currents may bereferred to as holding currents 0r currents at holding potential. Many` relays or receiving devicesare of suchdesign'that after being operated the device will retain itsk armature under the influence of la relatively weak holdingv current. In many'instances 1 this holding-current may have a. strength equal r to only ten .percent of the strength `of the v control current necessary for first operating the device. lt will also be clear that in double current working and in the control of telegraphic printers through permutationsof positive and negative impulses, a further improvement in trallsmission may be had Vby providing that after ,a 4first .impulse interval.` .any immediately followingA or successive impulselintervals requiring a like polarity may be represented by continuance of the low potential holding current as applied during the latter'portion of the first impulse interval in such a series. This elimination of-'the high potential control currents dur-ing successive repetition of impulses fof like polarityprevents an undue charging of'theline conductorzand also avoids vthe huildingup of unnecessary magnetic flux in the .receiving devices,1 each of which yeec'ts wouldihavc a: tendency to retard theVV trans- 1missionr ofsignalsasralready mentioned. lin

order ithat any tendency to asymmetrical charging of la line even to arelatively limited extent aslmay possibly occur'from aprolonged application of holding current of one polarityas described7 it will now be'further clear that if lthe liney conductor is Yswitched to earth following such an application of holding current the'circuit may thereby-be drained to a properffzerocurrent condition.

'In line with the features above pointed out as desirable fintheeiiicient operation of signaling circuits, the present invention contemplates an arrangement of transmitting apparatus including electroresponsive switching "devices whereby transmission currents-maybe controlled in such a manner that in additionrto expediting the charging" and discharging or-the effecting of current variations -in a line conductor proper,

Vthe responses of `the receiving devices may also be accelerated to a corresponding degree, `thereby maintaining arproper interrelation'between the various factors entering into the operation of a completecircuit.

This invention isillustrated diagrammatically in the accompanying drawing in which, for the 4"sake of clcarness5 only so much of the telegraphic transmitting sys temhas been -shown as will be necessary to l'a clear understanding of the features of the invention.

`Fig. l, illustrates a transmitting system suitableffor practicingthe features of this invention; Fig. V2 illustrates an alternate 'i arrangement ofthe system4 shownin Fig. l,

while -in Fig. 3 is shown an varrangement wherebythe present invention may be ein ployed in multiplex *telegraph working in -a manner suitable for the control of -telegraphic printing operations.

vin rdescribing this invention reference will first be had tofFigflof the drawing wherein a transmitter l may-be worked to close either thecontacts 2 orthe contacts 3 lay 4 separates its contacts V5 toy disconnect `a line conductor L from the circuit normally established to earth at the normal contact offthe l.relay 8., Ywhile closure of the contacts 6 apply the current which may have been selected: ley-the transmitter 1 to the line L. The-equalizing of current effects in Ythe condenserk 7 permit the :relay 4: to rele-aseand switchtheiline conducto-r Lby way: ofthe contacts 9 ofthe relay 8 and an .adjustable resistance l0 kto 'i the source of current which may have Vbeen selected at the transmitter. @nrv the transmitter being released*deenergization of therelay .8 again switches the line conductor to the earth connection. It will therefore kbe obvious that on the-instantthe transmit-ter is oper-j atedhigh potential or rcontrol current from the source selected may be momentarily. connected to the line and immediately following` this; beforev the transmitter is released, holding' current as :reduced in potentialby the resistance 110 will be substituted for the control current. f

Llhc contacts ofthe relay l are of the socallcd make-before-break7.type'in order that cessation ofcurrent will Vnot take place during moments the :armature of the relay may be in in oti on in switching' the line from the control to the holding lcurrent supply leads. A resistance lll'prevents excessive flow of current in the local circuit during instants ,the nicn'ibers forming the-contacts 5 and (l niay allpbe in engagement,.one with the other. A I V ln situal'ions where 'it maybedesircd'lo employ socalled1siugle ciurent working, one of the sources of.currentmay be dispensed with and, in order that the` condenser inay be relatively emptied betweenfsuccessiveapplical'ions of current of the same polarity, a switch l5 may be closed-to establislra leak7 1 circuit from the transmitting"leadtoearth This permits the resistance l() to be dispensedwith and in -fsubstitution thereof derived circuit points 16 and 17 are providedor the relays 8 and 12from the positive bat-y tery permit low potential holding current to flow from the'point 16 by way of the contacts 13, 9 and 5 of the respective relays 12, 8 and 4: to the line conductor L, and during corresponding energizatio-n of the relays 8 and 12 from the negative battery low-potential holding current may flow trom the point 17 y way of thecontacts 14:, 9 and 5 oi the respective relays to the line. As shwn, the line will stand connected to earth at the normal contacts of the relay 8 during periods the transmitter 1 may be out of engagement with the sources of current.l

ln Fig. 3 a multiplex distributor, preferably olf a suitable rotary type, is shown in developed form and comprises collector rings 19 and 20, segments 21 to 25 vand contacter' arms or brushes 26 and 27. Switching levers 551-35 represent contacts -to be controlled by means of a keyboard or a transmitting tape (not shown) and serve to prepare permutations of current polarities :from the associated positive and `negative sources for energizing the segments. The brushes 26 and 27 traverse their respective paths from left to right and the brush 26 successively joins the segments 21-25 to the ring 20 and current present on the vsegments may control the relays 4 and 12 inv a manner similar to that already described -for the corresponding relays, Fig. 2. rIhe brush'27 is so spaced with respect to the brush v26 that it may just be entering upon a segment, as the segment 22, at an instant the brush 26 may be just leaving the next last segment, as the segment 21. lhe brush 27 applies current from the segment 21-25 to the ring 19 to control the relay 8. In this arrangement the latter relay is to be or a suitable slow-releasing type in order that its zumature may be retained during periodsthe brush 27 may be traversing the space intermediate adjacent segments. The relay 8 will therefore continue in its operated position except during moments corresponding with the collapse of magnetism therein due to a reversalof current through its winding. This insures that no interruption or' low potential holding current from the point 16 or 17 as routed through the contacts of the relay 12 and the forward contacts 9 of the relay 8 may take place during prolonged intervals corresponding with successive im-l pulses ot like polarity as already described.

` it an instant the brush 27 may encounter a segment Aenergized by current {having polarity inverse to the current present on the segment last traversed by this brush the necessary reversal of magnetism will be established in the relay 8 to cause it to momentarily release and connect the line L to earth. @n the rinstant the magnetism ot'` .this relay builds up in the opposite sense in conformity with the current present through the brush 27, the relay will respond land close itsA contacts 9. In thismultiplexl arrangement it willbe understood that character selection impulses may be in accordance with the well-known five unit code of y Although the contacts of the relays 4 Vin `Figs. 2 and 3 have been shown as of the break-before-make type it will be understood that these relays may be of the maltebei'ore-break type as shown and already described in connection with the corresponding relay at of Fig. 1. f

lt will be understood that the transmitter l vol' Figs. 1 and 2 may be manipulated in a manner to continue an energization of the line by current ofy one polarity during peri ods corresponding with successive impulses ci like polarity. Therefore, `these equipments may effect continuous applications of 'holdingcurrent to the line to the exclusion or' high .potential currents during intervals corresponding with a second and any additional successive impulses of like polarity.- rlhe relays 8 of Figs. 1 and 2 may be adapted to respond relatively in phase with the transmitters 1, anch-therefore, it will be clear that the line may be switched to earth intermediate impulses or" opposite polarity in doublecurrent Vworking andto earth intermediate all impulses in the single current working as already described.

Through the present invention the application or' printing telegraph service'may be made to cable conductors otherwise having a time constant vof operation whichwould Y render the transmission rate or lspeed or' sending too slow for commercial service.

What is claimed is:` `1. A telegraph system comprising fa line circuit, a source of signaling current, an im' pulse transmitting device, a relay responsive to the actuation oiE said transmitting device to connect said line circuit to said source oi current, a condenser in series with said relay to limit the period of energization thereof, another relay also responsive to the actu-` ation of said transmitting device, and contacts controlled thereby to apply signaling current of lessened potential to said line upon the deenergization of said rst relay.

2. In a telegraphsystem a line circuit, a source of signaling current, a pole changer connected thereto, a relay and ay condenser in series, circuit connections whereby an operation or said pole changer causes an impulse of current to flow through said relay to f charge said condenser and thereby to cause a i lerity and potential to seid. line Circuit, fm'- ethe' relay else responsive to the actua-'tion of said pole changer ausl contacts controlled thereby for applying; emlentethe same p0- lzu'ty but of lessened potential lo said line crcult upon the fleenerglzetlen of Saud 10u-St relay. v

3. ln a 'telegraph system, n line circuit, sources of current, lst and second rel-ay means and a control circuit therefore1ectro ind-uclve means included with seid control for rendering `the responses of said fst relay means el' shelter lcluaciml than the responses el' seid. second relay means7 and Crcuts jointly controlled in the .operation of said vfirst and seeomil relay means for Successvely applying eur-fente clfefent potenale from Seid Sources lo szxcl line Without permitting cessation of eurent inthe line;

In witness whereof', l' :heeunto subscribe my name this 17th de); of November A, D., 1919. y l

HENRY YV. ON'ELL.

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