US1580225A - Telegraph circuit - Google Patents

Description

A ril 13,1926. 1,580,225

E. F. WATSON TELEGRAPH CIRCUIT Original Filed p 27. 1923 a [N VEN TOR ZZZ mills-0w ATTORNEY Patented Apr. l3,1926.

UNITEDSTATES.

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. Application filed'septeinber 27, 1923, Serial K0. 665,147. Renewed. lq'ovember 27, 1825- To all whom t may concern Be it known that l, EDWARD 1*. Mason, a

citizen of the ,United: States, residing at Yonkers, inthecounty of estchester. and

State of New. York, have inventedcertain.

Improvements in Telegraph Circuits," of which the following is a specification.

This invention relates totelegraph circuits and more particularly to improvements in the type of telegrapl1--.circuit known as single Morse circuits in which signals are transmitted in but one direction over the same line at one time, although thesystem is so arranged that signals may be transmitted in either direction. v r Y Y l 1 A two-way .polar'telegraph system of the above mentioned type is illustrated in detail 'in the U. S. Patent application, Serial No. 516,868, filed November 21, 1921, in the name of E. F. W'atson. Ithas been found inpractice that in the repeater sets-of circuits oi this type it is possible under certain conditions for the subscriber to be tie 'd up and unable to send. This'condition may occur when the break relay at the sending station operates falsely from any cause, such as a- ;llne swing, and thus causes the op'eratlon of. the transfer relay at that statlon. =.T he oper-;

ation of the transfer relay atthe sending station causes ground to be connectedto both ends of the line and the currentthrough-the windings of the receivingrelays to beap proximately zero. If at this time the armature of the receiving relay is held against the .spacing cont-acuby a spacing earth "c'ur rent or 'a spacing bias in the relay, theSubscribers loop will be practically short-circuited and it will be impossible for him-to send. It is in general the 'objectof'the' in vention' to provide arrangements for. the purpose of eliminating this possibility of the subscriberls being tied up or unable to 7 send. In the arrangements of the invention 7 this is accomplished'by providing relay arrangements and resistance elements associated with a repeater set which, when the above described conditions occur, will operate to restore the circuit to a normal condition again. Other ob ects and features of the invention will appear more fully'from the detailed description hereinafter given;

The invention may be more fully under stood from the following description, 'to{ gether with the accompanying drawing, in

the figure of which. is illustrated a cirouit diagram of a telegraph system embodying the invention. 1

cuit terminating at opposite ends at twosftal- Referring to the figure, L' designatesffa naln tlflIlSIIllSSlOILllIlO for a telegraph cin' :tions indicated-as A and B respectively.- At

as including a sounderS, a keyK'and a'posi- 'tivesource of potential. v I

1 ."The loop sL a Samoan is anneaby means of abalancing-circuit or resistance N and the wlndings of a polar-"pole,changing relay Pclland a polar break release relay BRR are included in the loop SL and the balancing circuit N. At the -'ju nction' point I between the loop SL and the balancing cir- 'Cul-iiN 'a-connection extends to the armature,

of a polar receiving relay'RR, which relay may, under certain conditions,"be associated Wltll' the main line'L for transmitting sig- :nals to'the loop. 1 -i'f A transfer relay TB is so arranged thatit may switch themain' line Leither intofconnection with the receivingrelay BR 01 into 1 connection w th the transmitting a paratus controlled by' ft-he' armature of the pole changer PC. The connection from the main line -L to the armature of thepolecli'anger BR. Thefbrea'kfrelay is .a na rginal neutral relay 'S'O dGS IgIIGCl that it will be un w responsive to positive or negative currents PC includes the winding jofa break relay".

transmitted'overthe line in connection with 1 ordinary signaling, but will be responsive to a current'of greater. amplitude transmitted over the line as th'e'result of a break signal. Associated with the"ftransferl'relayTB isa battery 45 and two. circuits, one of 'wliich is controlled by the armature of. I the. break relay BR for initially energizing the transfer-relay and the otherjof which actsa's' a locking circuit for the transfer relay; and is controlled over the contacts of the break release relay Associated withthese circuits are the resistance elements Band 6,

thc resistance element 16 being relatively greater thangthe resistance elements for purposes which will be pointed out herein after. Associated 'withibatteryc t is a third circuit 3, including the signaling means 2 and completed over the contact and arrna ture of the relay 1, which is incliuledserially in the line L for purposes which will be pointed out hereinafter.

With the exception that relay 1 and signal 2 are omittedthe apparatus at station B is substantially similar to that at station A and corresponding elements are represented by the same reference characters. primed. Other details of the apparatus will be clear from the following description of its operation.

As illustrated the apparatusat stations A and B is in condition for transmitting from station A to station B. Under these conditions, transfer relay TR at station B is locked up to connect line L to the receiving relay RR. At station A the transfer relay TR is deenergized so that the line L is connected to the armature of the pole changer .PC. When the transfer relay TR isdeenergized. a negative battery 4 is connected from the b ack left-hand contact of the transfer relay to the winding of the receiving relay RR so that the armature of the latter relay is maintained against its negative contact. Under these conditions, when the loop SL is closed, current flows from the positive battery over the contacts of key K through the loop windings of the break release relay BRR- and the pole changer PC and over the contact of the receiving relay RR to negative battery. Current also flows from ground to the balancing resistance N, balancing windings of the break release relay BBB and the pole changer PC and over the contact of the receiving relay RR to negative battery. Obviously, the current flowing through the loop windings of the pole changer and the break release relay is substantially twice as great as that flowing through the balancing windings owing to the fact that the positive and negative batteries are connected in series with respect to the loop circuit. The tendency of the current flowing through the balancing windings is to shift the armatures of the pole changer PC and the break release relay BER to their left-hand contacts, but owing to the greater pull in the opposite direction, due to the loop windings of said relays, the armatures are held to their righthand contacts so that negative battery is connected through the winding of the break relay BR and over the right-hand back contact of the transfer relay to the main line L. The resultant line current flows through the front left-hand contact of the transfer relay TR at station E and through the winding of the receiving relay RR to ground. The armature of the receiving relay ER is therefore held against its negative contact and the current conditions in the loop circuit SL are the same as described at station A so that the armature of the break release relay BBB is held against its left-hand contact,'thereby maintaining a locking circuit through the winding and over the righthand front contact of the transfer relay TR.

The conditions just described obtain through the transmission of marking signals. When a spacing signal is to be transmitted, the loop SL will be opened by means of the key K at station A so that no current flows through the loop windings of the pole changer PC and the break release relay BER. The balancing windings of these relays now become effective. The shifting of the armature of the break release relay is without effect but the'arinatur-e of the pole changer connects positive current to the main line L so that the receiving relay RR shifts its armature to the positive contact. The positive battery is now connected to both ends of the loop SL so that no current flows through the loop windings of the pole changer PC and the break release relay BRR. Current flows through the balancing windings of the relays PC and BBB in the opposite direction so that these windings are now energized in such a direction as to tend to hold their armatures against their lefthand contacts. Consequently, theshifting of the battery connections by means of the relay RE is without effect upon the armature of the pole changer PC and the break release relay BER. The incoming signal will be recorded by the sounder apparatus S.

If, while signals are being transmitted from station A,-dt is desired to transmit signals from station B, the loop circuit SL may be opened, as, for example, by means of the key K. As soon as a negative or marking signal is received from station A, negative battery will be connected tothe loop over the right-hand contact of the receiving relay RR. As the loop windings of the pole changer PC and break release relay BRR are deenergized, the balancing windings become effective to shift their armatures to their right-hand contacts. The shifting of the armature of the break release relay BER opens the locking circuit of the transfer relay TR, which 'is. den'ergized so that its right-hand back contact connects negative battery 4c to the receiving relay HR to hold the armature of the latter relay against its negative contact. At its lefthand back contact, transfer relay TR con nccts the lineL through the winding of the break relay BR to the armature of the pole changer PC; The armature of the pole changer is connected to positive battery at station B and it will be remembered that the changes just described occur at the time a marking signal is being transmitted from station A so that negative battery is connected to the line L at the latter station. This results in a current flow of approximately twice the normal amplitude through the windings of the break relay BR over the repeater equipment line L and through the windingof the break relay BR- at station A. Both break relays are energized but the energization of the break relay BR at station B is without effeet to energize the transfer relay TR owing tothe fact that the circuit of the latter relay is held open at thearmature' of the break release relay BER. Consequently, the transfer relay TRat station 13 remains denergized. At station A, however, the armature of the break release relay will be upon its right-hand contact owing to the fact that the loop SL is closed and upon the energizetion of the break relay BR 2. circuit-is completedfrom ground,:right-hand contact of break release relay ERR, Winding of transfer relay TR, contact of break relay BR, resistances' 6 and 5 to thenegative battery 4 The transfer relay TB is energized andat its left-hand contact completes a locking circuit' through resistances-6 and 5 tothe bat+ tery/t. This relay shifts the connection of the line L from control of the pole changer PC into circuit with the receiving relay RR. Signals may now be transmitted from station B to station Ain an obvious manner.

If the break relay at the sending station,

such as relay. BR at station A, should open ate falsely from any cause such as .a line swing, the transfer relay TR would, as has been seen, beoperated.v This operation of the transfer relay TR- would cause ground to be connected to both ends of the line and the current through the windings of the receiving relays to be approximately zero. If at this time the armature of the rece1ving relay is held against its spacing or positive contact by a spacing earth current or a spacing bias in'the relay the subscribefls loop I SL will be practically short-circuited and it will be impossible for him to send. Accordingly, the relay 1 and the resistances 5 and 6, together with the circuit 3, areprovided at station A in additiontothe usual heretofore described, Relay 1 is connected in series with the line L and is so adjusted that it will not be released on the normal signals but will be released if the line current becomes approximately zero from such causesas the transfer relays at both ends of the line becoming operated or from an open line. When the relay 1 is released a circuit is closed through the signal lamp 2 and over conductor 3 and resistance 5 to thebattery 4. This will operate the signal lamp 2. As has pre-' viously been pointed out, the resistance 5 is relatively small compared with resistance 6. The resistance'of the lamp 2 is also relatively very small as compared with resistance 6. Accordingly, upon the operation ofrelay 1 and the closing of circuit 3 the major portion of the current which heretofore flowed through the locking circuit of the transfer relay TR from battery 4 will be diverted over circuit 3. In other words, the current 7 flow through the transfer relay under these conditions will bereduc-ed to such a value, when relayivl releases that the transfer relay will'rbereleased. If'the trouble condition has been a transient one sending may be resumedfrom station A. If station B has been sending, he may resumeafter sending a break of spacing signal to'restore ap- Jaratus at station A to a receiving condition. In case the'trouble condition is not transient but persists as in the case of an a open line, signal lamp 2 will remain lighted and call attention to the troublecondition. While the invention has been disclosed in certain specific arrangements which have been deemed desirable it is understood that it is capable of embodiment in many. and other. forms without departing from the spirit of the invention as defined in the following claims. I Y

l/Vhat is claimed is: y I 1. In a signaling system, a linecircuit, terminal stations at each end ofsaidv line circuit, transmitting apparatus and receiving apparatus w at each terminal station, a transfer relay at each terminal station, said transfer relays being arranged to connect the transmitting apparatus to the line circuit atone station and the, receiving'apparatus to the line circuit at the other station fortransmission in one direction, said transfer relays being also arranged to shiftithe connection so thatthe transmitting apparatus will be connected to the line circuit at the second station and the receiving apparatus tothe line circuit at the first'station' to transmit signaling, currents in'the opposite direction, lockingcircuits for said trans- .fer relays, and'relay' means in series withsaid line circuit at one of said stations forf .cuit, transmitting apparatus and receiving apparatus at each terminal station, a transfer relay at each terminal station, said transfer relays being arranged to connect the transmitting apparatus to the line circuit at one station and the receiving apparatus to the line circuit at the other station for transmission in one direction, said transfer'relays so that the transmitting apparatus will be connected to the line circuit at the second station and the receiving apparatus to the beingalso arranged to shift the connection a one of said stations, and means controlled by said relay means for decreasing the current flow through the locking circuit of the transfer relay at said station.

3. In a signaling system, a line circuit, terminal stations at each end of said line circuit, transmitting apparatus and receiving apparatus'at each terminal station, a transfer relay at each terminal station, said transfer relays being arranged to connect the transmitting apparatus to the line circuit at one station and the receiving apparatus to the line circuit at the other station for transmission in one direction, said transfer relays being also arranged to shift the connection so that the transmitting apparatus will be connected to the line circuit at the second station and the receiving apparatus to the line circuit at the first station to transmit signaling currents in the opposite direction, locking circuits for said trans fer relays, normally operated relay means in series vith said line circuit at one of said stations and deenergized when a condition of no current exists in said line circuit, and means controlled by said relay means when deenergized for rendering ineffective the locking circuit for the transfer relay at said station.

at. In a signaling system, a line circuit, terminal stations at each end of said line circuit, transmitting apparatus and receiv' ing apparatus at each terminal station, a transfer relay at each terminal station, said transfer relays being arranged to connect the transmitting apparatus to the line circuit at one station and the receiving apparatus to the line circuit at the other station for transmission in one direction, said transfer relays being also arranged to shift the connection so that the transmitting apparatus will be connected to the line circuit at the second station and the receiving apparatus to the line circuit at the first station to transmit signaling currents in the opposite direc tion, locking circuits for said transfer relays, normally operated relay means in series With said line circuit at one of said stations and deenergized when a condition of no current exists in said line circuit, a circuit controlled by said relay means when deenergized for rendering ineffective the locking circuit for the transfer relay at said station, and signaling means controlled by said circuit.

5. In a signaling system, a line circuit, terminal stations at each end of said line circuit, transmitting apparatus and receiving apparatus at each terminal station, a trans fer relay at each terminal station, said transfer relays being arranged to connect the transmitting apparatus to the line circuit at one station and the receiving apparatus to the line circuit at the other station for transmission in one direction, said transfer relays being also arranged to shift the connection so that the transmitting apparatus will be connected to the line circuit at the second station, and the receiving apparatus, to the line circuit at the first station to transmit signaling currents in the opposite direction, the transfer relay at one of said stations having a plurality of operating circuits, and relay means in series with said line circuit at said station for controlling one of the operating circuits of the transfer relay thereat.

In testimony whereof, I have signed my name to this specificationthis 12th day of September 1923.

EDWARD F. WATSON.

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