US1675312A - Connecter-switch circuits - Google Patents

Description

Patented June 26, 1928.

UNITED STATES 'PATENT OFFICE.

JOHN XVICKS, F OAK PARK, LLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTSfTO AUTO- MATIC ELECTRIC INC., 0F CHCAGO, ILLNOIS, A CORPDRATION OF DELAWARE.

:ill

`comanornia-SWITCH` CIRCUITS.

Original application led .Tune 3,1922, `Serial No. 565,734. Divided and this application tiled April `17, Y1925, serial No. 23,754. Renewed october 19, 1927.

The present invention relates to automatic telephone systems in general, but is concerned more particularly with the provision of certain novel circuit arrangements to be employed in connection with the connecter switches, which are the switches that finally complete the connections between calling and called lines in automatic telephone systems.

According to one feature, a novel'circuit` arrangement has been devised such that the wiper-switching relay of the connecter switch 1s controlled over the called line. rThis 1s `done to prevent it fromenergizing to connect up rthe wipers and thereby project out ringing current until the cut-ott1 relay of the `called line has pulled up to `disconnect the line relay `of the line switch on the called line vtroni in bridge of the called line.

According to another feature o'l" this case, circuit arrangements are provided whereby the connection between the release trunk conductor and the guarding ground contacts of the switching relay is altered, so that the test w-indino oi' the switchin@r relais ea;-

eluded "from the `guarding' circuitwhile the `connecter switch is being'lheld by the cal-led line after the calling' subscriber' has replaced his receiver. Another point in connection with this arrangement is that the test winding,l oi' the switching -relay is not merely shorted but the connection to the release tri-ink conductor is shifted from one termi` nal ofthe test windinplr tothe other, leaving the test winding open so that it will not' `make the relay slow to release. i

" Accordingto still another feature, the circuit of the release magnet is taken through nornnilly closed contacts on the switching relay so aslo prevent the operation of the rel .e magnet before the switchingr relay Referringnow to the aceompanyine,r draw'` ingr, comprisinga single sheet, `this drawing shows-thc connecter ll, to which the foregoing features of theinvention are applied,

,togctherrwith the line switch Cand lthe as- .so-elated line coming into the exchange from the substation A.

F rom a mechanical standpoint the connecter H is oi the .usual vertical and rotary type of switch, having its bank contacts ar- 00 raneedin horizontal rows or levels.

he line switch C is, from a `mechanical standpoint, a switch of the well known ro tary type having wipers which are advanced upon the back strolce of the associated step- 05 pingr magnet and which have no normal po sition.

` The substation A, it may be pointed out,

is of theusual common battery type and has a calling device for controlling the auto-.70 matic switches in addition to the other well known parts.

It will be noted that relay 4:05 of the conf necter H is labeled Two step. This is to indicate that the relay operates part way `only under one condition and that it operates fully under another condition. In order to dill'erentiate between the contacts which are operatedupon the first step of the relayand those which are operated upon 8.0 the second step `of the relay, those contacts which close when thc relay is Voperated through its first step only are indicated by the numeral 1, and those contacts which are 'operated yonly in case the lrelay operates sa through its second step are indicated by the numeral. 2.` y

The invention having been described more orless generally, a detailed description of the operation of the `apparatus shown will 9o now be given. For this purpose it will be assumed that a subscriber on a calling;r line (not shown) desires to communicate with the subscriber 'at substation A. lt will be 'assumed lurtherthat, when the calling sub# 95 scriber removes his receiver and dials the y .first twodigits. the thousands `selector seized by the calling line switch seizes a hundreds selector' in the :thousands group in which the connecter H is` located` andthat the 10o seized hundreds selector raises its wipers opposite Vthe level of bank contacts in which the trunk line 'leading to the connecter H and comprising conductors S- 382 terminates. It will be assumed further that the trunk line leading to the connecter' H is the the line switch included in the connection.v

The calling subscriber may now operate his calling device for the next digit of the desired number. By this operation a series of interruptions is produced in the circuit of line relay 401 of the connecter H, which relay deenergizes a plurality of times in response thereto. At the first deenergization, a circuit is completed extending from ground by way of armature 418 and its back contact, armature 421 and its front contact, otl' normal springs 422 and 425, winding of the slow acting relaiy 403, and thence through the winding of the vertical magnet 409 to battery. The vertical magnet 409 operates to raise the wipers 450-452 step by step until the said wipers are brought opposite the level of bank contacts corresponding to the number of interruptions in the digit dialled.

Upon the first vertical step of the switch the off normal springs are shifted with the resultl that the last part of the first impulse and all of the remaining impulses to the vertical magnet traverse a new circuit which is the same as the one traced above except that it includes off normal springs 422 and 423, and armature 424 and its working contact instead of off normal springs 422 and 425, the slow acting series relay 403 being now energized. Relay 403, being slow acting, is maintained energized throughout thev series of impulses delivered to the kvertical magnet 409.

At the termination of the series of impulses relay V403 deenergizes, thereby transferring the impulsing circuit to the rotary magnet 410.

The calling subscriber may now dial the next and final digit in the desired number. As before, a series of interruptions is produced in the circuit of line relay 401. At each retraction of armature 418 on line rclay 401 an impulse of current is sent to rotary magnet 410, the path at the time of the first closure being as follows: from ground by way of armature 418 and its back contact, armature 421 and its front Contact, olil normal springs 422 and 423, armature 424 and its back contact, back contact and armature 431, armature 441 and its back contact, and rotary magnet 410 to battery. The rotary magnet 410 operates to rotate the switch wipers into engagement with t-he set of bank contacts associated with the line of substation A. The slow acting relay 406 is energized in multiple with the rotary magnet. At armature 433 relay 406 disconnects test wiper 451 from the test Winding of relay 407,

and connectsit instead to the test winding of busy relay 405, through armature 440 and its bacl; contacts, and at armature 434 this relay short circuits the back contact and armature 431 on the test relay 405. This latter operation, serves to preserve the continuity of the rotary magnet circuit while the switch wipers are being rotated over bank contact sets associated with busy telephone lines.

At this point it may be well to explain something of the function and manner of operation of the upper winding of the twostep relay 405. It will be noted that except for the upper winding and certain added contacts, this relay is the usual busy relay, and that the armatures 4304132 are the usual armatures found on the busy relay of an ordinary connecter switch. In the present case, however, this busy relay has a further function, and that is to prevent the premature energization of switching relay 40T by maintaining the upper winding of the latter relay short circuited at armature 429 until the bridge-cutoff relay of the line switch on the called line pulls up to disconnect the line relay, This, yit will be seen, is to prevent the false operation of the line relay from the ringing current which is to be applied to the called line, or, in case the private normal conductors of the called line are reversed, to prevent a premature energization of the ring-cut-of'1 relay of the connecter, which relay (in this latter case) would energize from the normal ground potential on the lower line conductor.

The arrangement for accomplishing the result-s above set forth includes the bridge across line wipers 450 and 452 through the upper winding of relay 405, armature 428 and its resting contact, working contact and armature 414 of line relay 401, and the resting contact and armature 435.y This bridge, it will be noted, includes contacts on the line relay 401. Accordingly, each time line relay 401 pulls up follmving a deenergization to operate rotary magnet 410, it connects the upper winding of relay 405 in bridge of the line wipers 450 and 452 unless the line encountered by the wipers is busy, in which case relay 405 will have operated through wiper 451, and the bridge including the upper winding of the relay is open at armature 42S. From this it follows that, if the line to which the wipers are advanced upon any one of the operations of rotary magnet 410 is idle, relay 405 does not energize through its lower winding, and the bridge through the upper winding remains closed across the line wipers. This upper winding of the relay is a high resistance winding so as to prevent the operation of the line relay of the idle `lay `is operated :through its `operates throiigh its iirst step and places a shunt around the upper winding of relay 40T to prevent the operation of the latter relay for the ltime lieing,without performing any of the other functions ofthe relay, which other functions are ,performed only 'when Vrelay 405 1is acting in its capacity as a Ibusy relay..

Assuming'Y -that the desired 'line is busy when the wipers -ot' the switch land upon the associated bank contacts, as pointed out above, there isa ground potential present on the test contact 455engaiged by `test con` tact ffl-l, and the test relay 405 is energized. Upon operating relay V405 at armature 430 establishes a point in its locking circuit which is completed upon the subsequent deenergization of the slow acting relay 40G; at

ari'nafturc 420 it short ycircuits the upper winding of relay 407:5;` at armature 428 it opens the circuit t'or its `own upper winding; at armature 431 itopens apoint "in the circuit of the rotary magnet; and at armature 432 it `connects 'a lead from the busy machine `to the `lower talkingconductor. This latter action results in the transmission oit an audible ytone to the calling subscriber whois thus `notifievcl that the desired l-ine is busy, and he will replace his receiver 1upon che switchhook, thereby initiating the release of the operated switches `in a i-malnner which will be `described later.

llt will now ybe yassumed that the line `of the substation A is idle when the .Wipers 450w 452 are brought into `connection with the bank contacts 454-456;` 'Under these `conditions there will be no ground connected to testcontact 455, and nofcircuit is completed for the lower winding lof test relay 405. Accordingly, the upper windingol relay 405 remains bridged across theline Wipers, with the result that the relay operates through its first step only and shuntsthe upper winding ot relay 407 at armature 4429. Then, when, upon the deenergization of the slow acting `rch-1y"40G, `the circuit is completed extending. 'from `ground on release trunk conductor `381 by Way of armature 430 and its back contact, normally closed springs controlled by armature 437 upper winding of the switching relay 407, back contact and armature 433, test wiper 451, test lContact455, winding `of the switching relay 470 of the line `switch C', and thence to batteryfthrough`the winding of the rotary magnet 474, relayw407 remains inert because its upper winding short circuited at armature 429.

The rswitching relay 470 `of the line switch C energizes over itsabove traced circuit to disconnect the normal battery and round connection from the called lne in tlie line switch C. This latter operation opens the `circuitof the upper winding fof the test relay 405 which deenergizes `so as to remove the short circluit from around the `upper winding ofV the relayj407 Relay 407 thereupon energizes andfat its armature y439 establishes a `locking circuit for its; lower wind-ing; opens a point in the circuit of the lower winding of busy `relay 405'at armature 440; disconnects `rot-ary magnet 410` at armature 441; .opens al pointjin the `circuit of release magnet 408 at armature 442; replaces direct groundvon test wiper 4511alt armature 438; closes the ring-back tone circuit at armature 436i; disconnects the vback contact of armature 1430 from the Aupper terminaloi relay 407 and connectsitto the lower terminal at armature V437; andat ar'- matures 435y and 443 connects yup the line wipers 450 and452, at the same time `disconnectingthe upper winding 'of relay 405 from 1in bridge ofithe said 'line wipers.

Ringing current `from lthe generator GEN. is now intermittently projected "out through the jupper winding of the 'ring-cut-olt relay 404, and 1through wiper 450 to the called line to ring the bridged bell atsubstation A', and it returns over the lowertalking conductor to ground through the back con tact of armature `427. i i

`When the 'subscriber at substation A respondsito :the `ri'rnging oft' his bell by frei movin-g his receiver, ring=cutioff relay 404 energiz'es 'overlhis lline; closes a 'locking Icircuit for itself at armature 426; and a'tarlnatures 425 and 427 disconnects wipers 450 and452 ifrom the generator lead and Iground and connects them to the windings ot the double wound back bridge relay 400. Relay 400 now energizes over the called line and places a multiple ground 'on the llocal locking conductor at armature 41:15; and at armature 416 and 417 reverses thelconnection of conductors `380` and 382 to `ljine relay 401, there# by reversing the direction of ictn-rent flow in the callingline. y This latter operation is standard practice and is utilized in some casesto `operate meters, give supervision, andthe like. y

The `calling `and called subscribers may now converse with each other as'desired land when the yconversation -is `terminated they both replace their receivers. y p Assuming that the `-subscriber ,at substation A replaces 'his receiver hist, back bridge relay '400 falls back and disconnects at *armature 415 the "second Lgroulncl conneclil() tion from the local locking conductor, and at armatures 416 and 417 reverses the current How in the calling line back to normal.

When the calling subscriber replaces his receiver line relay 401 falls back and closes the usual impulse circuit at armature 418 and its back contact. Rotary magnet 410 does not respond at this time on account of the fact that it is disconnected at armature 441 of relay 407. The slow acting relay 406, however, pulls up overthe impulsing circuit and disconnects the release trunk concircuit of slow actingrelay 406 and prepares a. circuit for release magnet 408, which circuit, however, is still maintained open at armature 442 of switching relay 407. At armature 419 relay 402`disconnects ground from the local locking conductor whereupon the ring-cut-off relay 404 and switching relay 407 both fall back, and relay 407 completes at armature 442 the circuit of the release magnet 408 through the upper pair of olf normal springs. Release magnet 408 now energizes and restores the wipers 450-452 to their normal position in the usual manner. The circuit of release magnet 408 is opened at the off normal contacts when the switch shaft attains its normal position. Relay 406 now falls back, but it does not ground release trunk conductor 381 because relay 407 has restored.

For the purpose of illustrating the feature of the invention having to do with guarding the connecter H while it is held by the called party, it will now be assumed that the calling subscriber replaces his receiver before the subscriber at substation A replaces his receiver. That being the case, line relay 401 falls back as hereinbefore pointed out when the receiver is replaced at the calling subst-ation, opens the circuit ofV relay 402, and l closes a circuit for relay 406. Accordingly, relay 406 energizes as before and disconnect-s the grounded `test wiper 451 from the grounded release trunk conductor at armature 433. A moment later relay 402 falls back and disconnects ground from release trunk conductor 381 at armature 420, allowing the line switch and selectors to release in the usual manner. At arma-ture 419 relay 402 removes ground from the local locking conductor, but operation is ineffective at this time on account of the fact that this conductor is maintained grounded at armature 415 of back bridge relay 400. As afurther result of its deenergization, relay 402 opens the circuit of relay 406, as before, and prepares the circuit of release magnet 408. After the usual interval, relay 406 falls back and again connects the grounded wiper 451 to release trunk conductor 381 at armature 433 and its back contact, through armature 437 and its front contact, and the back contact and armature 430. This operation serves to guard the connecter H against seizure. Y

When the subscriber at substation A replaces his receiver, back bridge relay 400 falls back and removes ground from the local locking conductor at armature 415, thereby unlocking relays 404 and 407. lVhen relay 407 falls back, it removes ground from the release trunkconductor and from the private wiper 451 at armature 438, and at armature 442 completes the circuit of release magnet 408, whereupon the switch is lrestored to its normal position in the usual manner.

What is claimed is:

1. In a telephone system, a telephone line, a connecting circuit, means for extending a connection through said circuit to said line, a relay in said circuit toV complete the connection to said line, an electro-magnetic responding device connected to said line, means controlled by the extension of the `connection to said line for disconnecting said device therefrom, and means for preventing the energization of said relay until such disconnection is effected.

2. In a telephone system, a telephone line, an automatic switch for extending a connection thereto, a relay in said switch adapted to complete the extension of connection to said line, a battery connection on said line, means controlled by the extension of the connection to said line for removing said battery, and means for preventing the energization of said relay until said battery is removed.

3. In a telephone system, an automatic switch, a telephone line accessible thereto, means for operating said switch to extend a connection to said line, a relay in said switch for completing the connection, and means operative to delay the energization of said relay for a predetermined time.

4. In a telephone system, an automatic switch, a telephone line, means for operating said switch to extend a connection to said line, a line relay and a cut-'olf relay for said line, a source of ringing current, a relay in said switch for connecting said source to said line, means for completing a circuit for said cut-oil' relay when the connection is established to energize said cut-olf relay to remove the associated line relay from in 0011- y 1,675,312 i v nection with the line, and a second relay in said switch energized in series with said line relay when the connection is completed to prevent the operation of the first mentioned relay until the said cut-oft relay has operated.V

5. In a telephone system, a plurality of telephone lines, each line having a talking conductor anda test conductor, an automatic switch having `a test wiper and a line wiper, a line relay and a stepping magnet for 'said switch, a circuit including normally closed contacts on said line relay for operating said stepping magnet to bring said wipers successively into engagement with the respective conductors of said lines when a desired one of said lines is called, a busy relay connected `to said` test wiper during the stepping operation of the switch, and a test relay winding connected to said line wiper during the stepping operation through normally closed contacts on said busy relay and through normally open contacts on said line relay.

'6. In a telephone system, an automatic switch having a line wiper and a test wiper,

a test relay winding connected to said line wiper, means for bringing said wiper successively into engagement with the contacts of telephone lines, and a busy relay operated through said test wiper when aV busy line is encountered for disconnecting said test relay winding from said line wiper.

7 In a telephone system, an automatic switch having a line wiper and a test wiper, a test relay winding connected to said line wiper, means for bringing said wiper successively into engagement with the., contacts of telephone lines, a `busy relay operated throughsaid test wiper 4when a. busy line is encountered for disconnecting said test relay winding from said line wiper, and contacts opened during the advance of said wipers from one line to another to disconnect said test relay winding from said line wiper to prevent the closing of the test relay winding circuit to a busy line before the busy relay can be operated.

8. In a telephone system, a connecter switch having line and test wipers, a test conductor for said switch, a relay for connecting said line wipers to said switch, a winding on said relay having one terminal connected to said test wiperand having the other terminal connected to said test con-` ductor, a circuit for operating said relay by means of said. winding by current flow from said test conductor through said Winding and through said test Wiper, contacts on said relay closed when it pulls up to connect up said wipers for placing a guarding potential directly on said test wiper, and

other contacts for opening the connection between said test wiper and said test conductor y through said winding and for establishing .a new connection between said test wiper and said test conductor exclusive of said winding.

9. In a telephone system, a telephone line, automaticl switches for extending connections to and from said line a cut-off relay associated with said line operative when the line is called to disconnect the automatic switch used for extending calls from said line, means associated with the automatic switch used in extending a connection to said line for transmitting ringing current thereto, and means for preventing the transmission of ringing current to the line until after said cut-ofiI relay has been operated.

10. In a telephonesystem, a line, an automatic swltch for extending a connection and transmitting ringing current to said line, line` and cut-olf relays for said line, the line relay being normally connected to the line, and means for operating the said cut-olf relay to disconnect the line relay when the line is seized and vprior to the time ringing current is transmitted to the line.

11. VIn a telephone system, a line, a connecter forextending connections to said line and for thereafter transmitting ringing current thereto, a cut-off relay for said line, and

`line until after the cut-off relay has operated.

13. In a telephone system, an automatic switch equipped with a test wiper, a. test con# ductor for said switch, a relay in said switch,

a winding for said relay having one terminal connected to said test conductor and having its other terminal connected to said test i wiper, and contacts onsaid relay for placing a common guarding potential directly on said test wiper and test conductor.

14. In an automatic switch, a test con-` ductor for guarding the switch against seizure when in use, a test wiper, a` rela for placing a guarding potential upon sai test conductor when t-he switch is in use, an o eratingcircuit for said relay including sald Vtest conductor and test wiper, and contacts on said relay for connecting said test conductor and test wiper together, placing a guarding potential thereon, and for opening said circuit.

In witness whereof, I hereunto subscribe my name this 10 day of April, 1925. JOHN WICKS.

Images