US810345A - Telephone party-line system. - Google Patents

Description

m. 810,345, PATENTE JAN, 16, 1906... A, F. PGULE @L P, B. HALL.

TELEPHONE PARTY LINE SYSTEM. APPLIGAQON H LED 00T.1a,1902.

4 SHEETS-SHEET l.

10.810,345, 4 MT1-:MED JAN.1,6, 1906.` A. F. .POOLE @L F. B. HALL.

TELEPHONE PARTY LINE SYSTEM.

APPLICATO'N FILED 0C'T.13,1902.

4 SHEETS-SHEET 2.

1255125- {NEVI-hm l NI). 810,345. PATENTD JAN. 1'6, 1906. A. I'. POOLE L I'. B. HALL. TELEPHONE PARTY LINE SYSTEM.

4 APPLICATION IILBD OGT. 13,1902.

4 SHEETS-SHEET No. 810,345. PATENTED JAN. 16, 1906.

A. E. POOLE & E. B. HALL.

-TELEPHONE PARTY LINE SYSTEM.

APPLICATION FILED 00T.1s,1902.

.4 SHEETS-SHEET 4.

WIUEEEEE-.u IULETLLH A Darla? UNITED sTATEs PATENT OEEICE.

'ARTHUR -EQPooLEAND 'FRANK B. HALL, or WHEELING, wEsT VIRGINIA.

A.ToV 'aLZL whom it coun/cern:I

ro companyingdrawings, forminga part of tb'is speciic ationfl invention, relatesto tele TELEPHONE PARTY-LINE SYSTEMI Be it known that we, ARTHUR F.' PooLE liana FRANK- B. met, citizens of the United States, residing at Wheeling, in the countyfof Ohio and State of West Vilia,ha've invent'- ed a certain new and usefu Improvement in Telephone'Party-Line Systems, of which the following is a full, clear, concise, and exact 'descriptiomf 'reference being Ahad to the achone partylinc stems,A andmore particu arly to what .1 svstem includinga new selecting-circuity termed Party line selective 'sysf tems; 7 l

The 'I cipal 4.objects of our invention are to provide a new and. improved party-line therefor and roved'switching mechanism itheifadjustment, and therefore zfo'ruse therewit and thereby to overcome 'the defects in the construction and operation of party-line systems heretofore emp oyed. rtline systems of the pxllior art ma be divide i* into two classes.' .ilasses the apparatus installed at a sub--y rds'pond only to currents of a certain nature wit respect to their strength or polarity', or both* Such systems arenecessarilly delicate in iable to get out ofoperative condition. Suchsystems, furthermoreyare necessarily limited' to a small number of stations on each line. AThe other class of'party-line systems employ what is gen-v erally known as step-by-step devices. In 'this class or' systems step-by-step mechanism is installed at each of- .the substations ona party-line, the said mechanism being operated in synchronism with mechanism vat the centralstation. In 'such systems the -m'ech-v anism at all of the substations on anyone party-line must 'be operated at 'the sametime, thereby requiring a very powerful current. A further defect in manyv of these step-bystep party-line systems has been,. that on account of the complication ofthemechanism employed, it was very subject to derangement, and a'further. ditiicultyarose in that the derangement of the mechanism of any one station was liable to throw out of op@ all -t e erative condition the mechanism at other stations on the same line, such a general derangement often requiring the personal attention of anexpert at each of the statiqns on a line.

Qur invention contemplates animpi'oyed ,Specification of Letters Patent. Application iled October 13, 1 902. Serial No. 12'l ,113.

invention we one of t ese Patentedl Jan. 1.6, 1906.

'system in whichv these-defects and diiiiculties are overcome; In accordance with our rovide a selective part line systemin which the apparatus instal ed at each ofthe substations on a line is operated individually, the apparatus at the substations being operated successively. This operation di but one set of ap aratus at a time enables the operationo the system to be accomplished with a relatively small amount'. of current or strength of current.

The system-may be employedwith any partyline without requiring the installation of new telephone apparatus, the system being Wellada ted for use with any type of telephone an telephone-circuit.

l Another advantage obtained from the use of the system of our invention consists .in the fact that the apparatus installed ateach of the stations is a` uplicate of that installed at all the other stations. Therefore the special adjustment of each subscribers apparatus is unnecessary and the cost of installation is' thereby materially decreased.

Other -great advantages obtained by the' use of our present system consist in the fact that none of the currents used in the operation ofthe selective apparatus are broken atA the substations,` it being a well-known'fact among those skilled in the artthat the use of make-and-breakcontacts at party-line su'bstations-give's rise to much dxfliculty onl account of the oxidation and deterioration of such contacts due to the sparking caused upon the breaking of the current.

Our improved system presents a further advantage over those heretofore emplo ed in the fact that the strengthof the selectingcurrents is not material to the proper operationof the substation apparatus.

The objects of our invention are attained through the provisionzof a double metallic.

lme, one side of which may be continuous throughout the length of the line, each subiscribers ap aratus .being desirably provided -with a bri ge connection therewith. The -other side of this metallic line may be looped in at each of thesubstations, one side of each ofsaid loops beingv connected with a art of the subscriber? s selective apparatus.

of the substations this loop may beprovlded with a normally open contact; A art of the operation of the system includes t e succes; sive closing of these loops, thereby buildingup this loop-linethrough the succes'sivesub-y stations. The continuity of the loop-line is los teach .45 occur until t thereby attained., there being established by this building-up process two continuous metallic lines extending from the central station associated therewith to the farther end of the 5 party-line.I --The circuits used in this build- .ing-upvprocess may be established, as desired, either through one of the lines in connection with a grounded return or through thev two lines themselves..

- `ro A further result of the proper operation of the. selective apparatus consists 1n bridging the desired. subscribers telephone across the two metallic vlimbs of the party-line -as previously established. Normally each i 5 subscribers .station may be provided with a ground connection, particularlyT if the ground- -ed return is used 1n the building-up proc-7 ess previously referred to, a further result of the setting-'up operation of the selective ap-l zo paratus being to break this normally grounded connection.

Our invention further introduces a new-.

andeHicient'lock-out system., it being impossible when the line is in use by lany one party e 5 on the line forwany other party on' the same line to either listen in or signal or in any manner disturb lthe subscriber who is entitled to the use of the line, and a still more particu# laradvanta' e-ofv` our lock-out system over 3o those hereto ore employed resides in the fact that the said lock-'out feature is entirely automatic, it being aguinherent feature ofthe party-line systemritself, and no special provisions are necessary wit our system in orfdentosecure'thelo E feature.` x Some lo FA ost desirable Objects of our .inv'entio/Il- ',are attained by the provision of.

selective apparatumfor thesubstations, the circuit breaking or changing operations of 4o whichare accomplished aftera proper 'flow of current therethrough has ceasedthat is upon what might be termed its reversef' stroke. Many novel features are incorporated in the construction and mode of opera- ;o tion of this improved selective apparatus,

which, in addition to the other features of our invention, will be best understood by reference to the accompanying drawings, in

which- 5 5 Figure 1 is a diagrammaticview showing the cireuitonnectiosemployed in the operaft/ion of oursystem/including a central-station equipment which may desirably be used in connection therewith. Fig. 2 is a side eleva construction ofthe said selective apparatus.

In all ofK said views similar reference characters are applied to like or corresponding parts. l

The precise arrangement of the central-station equipment employed is not pertinent to the present invention, it being merely necessarythat central-station apparatus-beprovided whereby currents of desired polarity may be sent over anydesired' circuits of the party-line. We have, however, shown a manually -operated central station equipment suitable for use in connection with our partyline system.

Since the circuit arrangements of ourv system, the sequence, of electrical connections made, and other features of the operationl thereof will not be readily ap arentwithout an understanding of the mec anical devices employed to carry outour invention, we shall vfirst describe the mechanical construction of the selective apparatus employed and thereafter trace the electrical circuits used in the operation thereof. Y 4

The selective. apparatus is mounted on a base 1, to which are secured the horseshoe # electroma ets 2 and 3, the front endscf the cores of t ese electromagnets ca the sheet-metal frame-piece,` 4. Carried by the studs 5 5which extend from the frame-piece 4, is the horseshoe-electromagnet 6, this electromagnet being provided with a permanent polarizing-magnet 7. A frameportion 8 is adapted to pivotallysupport' the f armature 9 adjacent to thepole-pieces ofthe electro` magnet 6.- VThis armature isoperated only upon a flow of the current. through theelectromagnet 6in al certain direction on account of the polarization of said armature causedby the permanent magnet 7. lA detent 10 in the shape of 'a bent Wire is 'secured to the armature 9, the purpose of which datent will be hereinafter'more fully setfjorth. Near.

the center of the front framework ofthe deviceis provided-a'fxed shaft 1 1, upon which l are rotatably mounted various pieces of mechanism. `Thus rotatably mounted' u on the said shaft is provided the spur-W ee'l 12,

there being rotatably associa -d therewith a' ratchet-Wheel 13. lt Willbe n f'ticed'that the ratchet-wheel 13 has twice as many teeth as there are spurs on the' spur-wheel 12. A

ratchet-pawl14 prevents the rotation of the ratchet and spur wheels in a clockwise direc- .tion.' Aweighted lever 1 5 is rotatably mount# ed upon the shaft 1 1 just back of the ratchetnoi c/tion of a set of selective apparatus intended The upper aii'r'of th's'cross-bar 16 carries a x25 `/'to be installed at a substation, parts being pivot-ed ratchet-pawl 17, adaptedto engage broken away to more clearly reveal the opthe teethof the ratchet-wheel13. l arma- .eration thereof. Fig. 3 is a front elevation ture 1,7 is pivotally mountedto swing from of the same with other parts similarl broken the normal position `(shown' in Fig. 3) into 65 away. Fig. 4 is .a View illustrating etails of alinement with the pole-,pieces of the electro- 130i magnet 2,

a stop 18 beingr provided to deter- 'mine the swing of the armature. I This armature 17 carriesa downwardl fro'ectino' nin 19, so disposed as to engage a pin 20,projecting from the back of. the cross-lever 16. Thus upon the energization of the electromagnet 2 its armature" is drawn into'line with the polepieces, thus causing a motion to be communicated through the downwardlyprojecting lever-pin 19 and the pin 2O to the cross-amr' 16 of the lever 15.

The rotary motion of thlslever mechanism will bein a clockwise direction, suiiieientto draw the pawl 17 back. over one toothoi the. ratchet-sheet .13. contains the two ternnnas 36 and When a current has stopped flowing through the elect-romagnet 2, the weight of the lever4 15 is sufficient to transmit power through the pawl 17 to the ratchet-wheel 13, thereby turning it the space oi'4 one ratchettoothin a contra-clockwise direction, it being remembered A that on account of their rigid association the spur-wheel 12 willl rotate in correspondence with the ratchet-wheel 13.

Referring'-now to the electromagnet 3, it will be seen that it also is provided with a stop 21, limiting the motion of its swinging armature-22, which in turncarries a lever-pin 23,'adapted to engage a pin 24 on the'lower projectingarm of the cross-piece 16.. Thus an energization of this lower electromagnet 3 will cause the weighted arm of the-lever mechanism to rise` and upon its release to cause the rotation of the ratchet-Wheelthrough the space 'of one notch in a manner similar to that- 'v to say, a temporary current either the electromagnet 2 or theelectromag- A nets?) vwill cause a similar operation of the produced by theelectroma net 2-that is lever mechanism and the ratchet-Wheel and spur-Wheel associated therewith. A

A rotatable shaft 25 is provided with suitable bearings a d carries upon its outer end an exhausted -ass bulb 26,- containing merest illustrated in Figl 4, this shaft 25 is further provided with a tail 26',

1 adapted to be-actuated by the spurs of the -bulb ,to-be' tilted baclir'into its normal posi- A'wheel 12. 'A weightedv lever 28 tends to maintain the mercury-bulb in a tilted or normal position. (Shown'in Fig.'3.) It will be seen that upon the rotation of the s ur-wheel through the spaceof one ratchet-w eel tooth the tail 26 will be engaged by a spur ofthe spur-wheel 12to raise the said tail into its alternate ositionas shown in dotted lines in Fi 4, t ereby causing the mercury-bulb 2 6 to e tiltedinto its alt rnate position. (Also indicated indotted ligles.) Itwill be seen', furthermore, lthat a e tooth will cause the disengagement ofthe upon the Weighted lever-28wil1fcause the tion, as shown in Fi 3.

Itshould be noticed here .thatfplatinum owing,through nd rotationl of the spur-wheel through thfe space of one ratchet-'A vmine.

Wires are sealed into the 'tube 26 in vsuch al a*way that the bulb and the inclosed mercury form a tive-contact switch. .T he Contact 29 1s 1n contact with the mercury in either of its alternate posit-ions, the contacts 3 0 and 31 -being brought into Closed connection therewith when the mercury-bulb is in -its normal position, the'contacts 32 -and.3 ,3 being bron ht into contact withthe common ter- 29 when theniercury-bulb is in its alternate or' abnormal position.

Referring nov.' to the second mercury-bulb 34, which is similari)7 .mounted upon a rota.- tztbic sii-ait 35, it u iii beseen that this bulb which terminals are connected by the. inciosed mercury only when the bulb 34 is in'its alternateposition, (indicated in. dotted lines,) l

The normal disposition of this tail 40 to the spur vof the spur-wheel adjacent thereto is such thatthe release of the.detentcam39 by The dethe detent-wire 10 will allow the we'ehted'-le-- ver 41 to cause the tilting of the bul l34 into its alternate or abnormal position, thus causing an electrical connectionv between theterminals 37 and 36. Alotation of the'spurwheel, however, causes the engagement of a t e said tail, thereby rotating the bu "34 and its associated datent-cam 39 back 'into their normal position, where lthe detent-wire 10 slips over the cam-surface and thereu von catches the detent ed e of the .cam 39. .'-l us the bulb 34 is retaine in its normal positon',`

. (shown n Fig. 3,) except upon the actuation of the polarized armature 9, whereupon the datent-wire releases the cani39,- thus permittin the tilting of thebulb;

he circuit connections 'of 'the selective api aratus are diagrammatically illustrated on ig. 3, Where it will be seen that a connection is made between the binding-post A, tl1rough the Wire 42, to the fuse 43 connections being made from this oint tothe terminal 29.511 the bulb l26 and to t e terminal 36' `in the" bulb 34. electrical connection is made between the binding-.postG'., through the wire 43,' to the electromagn'et 2', the said electronia'gnet`be-- ingconnected'inlseries, through 'thejttfire 4.4, with thegelectifomagnet 6 fromwhich the remannng connection is made`thfough`the*wire 45,- withv the tei-mind so in the Bulbzcf.' Cons nection'is made/from the Vbindin, 1f' post B,

spur thereof with the tail 40, so as'to de ressloo the bulb 26. shown, between the binding-post' A and'the through-the Wire'46, to the binding-post T, lfrom which 'al Wire 47 leads to the electromag- .net 3, thefr'emaining .terminaljthereof bein connected bythe 'wire 48 with the termina Connection is made, as

contact.33. A wire 49 connects theI binding- )ost T with d the terminal 37 in the bulb'34. he contact` 3'1 in the bulb 26 is connected with the binding-screw '50, r'o'm'whichga con-A nection is made'wit'h-the contact. 51 of a 'key' 52. (Shown only in the diagrammatic view,.

Fie. 1.)

-laving thus described theselecting mechconnected with any desired number-of substations',- 'Infthe diagrammatic figure, however, Lwe have shown vvbut two 'such substations- 201' and 202; connected with the line, it

being understoodthat the remaining substa- -tions 'are ,connected therewith in an exactly similar.l manner. `Onaccount of the impossibility of satisfactorily illustrating in diagrammatic drawing? all the mechanism necessary to carry outthe operations in our sys" tem we have merely'atte'mpted to illustrate. in the selective appara tusthe electroma ynets and' the `electrical contacts controlledl t'ere-' by.' Referring more' articularly to. Fig.'1',.

we haveshown a meta lic telephone-line con-.5 l

lwnly when a, current flows in the -proper disist' vor 'the line b,"which runs straight through `from the exchan eto all of the substations without a brea, and the line a,v which is desirably looped into. each ofthe sub*- stations.... The line-wire aznay be connected with `-a ti -spring y53 andthe line-wire Zr withthe' s ecirc-spring 54 of a spring-jack at the central station. A contact 55 normally makes connection Withfal'ong jack-sprin and is connected througha line-drop 56 an A the battery 57 with the ground Gr. In the further description of Fig. 1 ,it should be' 36 in the bulb '34.

borne in mind that merel the circuit .connections are indicated and t at the electromagf nets shown correspond with an-electromagnet "having similar reference' characters in the. .other figures. It4 should urthermore be bornein mind that the-circuit changes caused by the e1ectromagnets2 and'3 are not,

brought about except upon the reverse stroke of the mechanism operated'thereby. ,Y Tracin the' circuit from the-tip-sprmg 53 through t e line-Wire a, we come to the' binding-post A, from which it will be remembered a connection was made with the terminal contact 29 in the bulb 26 and with the terminal such a position that the terminal 29 is -connected,

ymeans of the mercury,'with the tere Normally the bulb is in' the various conditions of operation to which V`a party-.line system is subjected. First, taking that condition under which la party on a party'-` line--for instance, at' station 202- wishes to call central and remember' that the circuit between` contacts and 37 is normally open and that connection is. normally made between contact 29.and contacts 30 and 31 the subscriberat station 202 makes .connection-between the. key 52 and thecon- -tact 51.- IfIe thereby closes'the following circuit: from contact 51 tovcontactfBl, tocon-' tact 30,- to electromagnet `6, through, wire 44, to electromagnet 2, to binding-post -Gt ground G, through ground -to battery 57,' to dine-drop 56, to contact 55, to-spring 54, to

line=wire 5,to bindin bo'st B atsubstation 202, 'to bindin -p'ost ,-tokeyf52. Thus we have traced t e'circuit which will energize the two electromagnets 2 and 6, it being re-4 membered'th'at the electromagnet 6 is provided With a polarized armature operated rection through' -the 'the ground, such t4 at the current fiowing' throughany electromagnet 6 located a't any vof thexsubstations on the line will fiow through' the said'electromagnet in sucha di# reetiomas to operate the'armature, thereby releasing the-trip, which permits a' tilting of the bulb 34 to make connection Abetween thecontacts 36 and 3 7. The energization of-the electromagnet 2 While this current Hows will. have caused the operation of the lever mechaniSm 15 16. i ,y

' U' on the cessation ofthe current-flow the ratcl 'et-mechanism .will be operated by the reverse'stroke of the lever mecha nism, through which the connection of the terminal 29 from that'with the contacts 31 and 30 is changed to a'connection with the'contacts 32 and 33'.

.The telephonie a paratus 58, installed at substation' A202, wil thereby have been con- IIQ u l 5 i vnectedin brid e across the metallic limbsof the tele hone'- ine, a condenser59 being'connected 1n the telephone-circuit to prevent -a lowsof. battery-current therethrough. lt

will be seen, furthermore, that through the depression of this key 52 and the ensuingo erationof the mechanism controlled by the e ectromagnet2the -loop in'the line-wire a, connected inat station 202, has been closed, thereby affording acontinuous electrical path through the line-Wire a, so far as the-substation 202 is concerned, it being apparent that thisnormally open loop is electrically closed vby. the connection of the Contact 29 with the`v circuit ynormally includes the line-drop 56 andthe battery 57.

"flt'will be seenfthatthe'tip-strand 61 completesfitscircuit partially through a Spring 62 which in its normal position makes contact l' With'- the ,remainder ofthe tip-strand.' `The sleeve-strand 63'is likewise connectedwith a key 64, -whichfnormally is connected withthe remainder of the operators usual cord-circuit. The operators cord-circuit need not be particularly described, .in that it is fami-liar to'those skilled in the-art. It is provided-w-iththe usual and listening key 65 and the lassociated generator and op- Aerator's telephone set." .Bridged across t e cord-strands is the disconnect signal-relay 66. The calling-plug'67 may desirably have keys 68 and 69 connected in circuit therewith, the operations of these keys being hereinafter.

more fully set forth.'v l

After plugging. into the answering jackI the operator depresses the key 62, thereupon -making a connection between the tip of the plug 60 and the conductor 70 of the polechanging circuit71. This pole-chan lring ar- -rangement cbnsists, essentially, of a attery 72,-Which by proper manipulation -of the springs` 73 and 74, may haveeither of its poles, as desired, connected with the condn'ctors 70 or 75. The operator manipulates the pair of springs 73 a number ef times, at least'as great' asrthetotal number of stationsl connected. withthe calling arty-line. -She thereby closes a circuit, Whicxii 'maybe traced as follows: from lthe positive pole of the battery 72, through the upper spring 73, to conductor'75, to ground G,there being no circuit connection between the conductor 75 .andthe key 64. The circuit maybe traced through the ground tothe binding-post G of the substation 201 thence through the corregionding-'electromgnet 2 and the lelectro- 4 inagnet 6,'to contact 30, to cont.act 29, to bini'- ing-post A, to line-Wire a, to tip-spring 534:1?0

owing through" tip-strand 61, to spring 62, to conductor 70,

to the lower spring 73, to the negative pole of the battery 72. There will be no such c ircuit formed from the ground of subscriber A202 to thea, Wire, becausethis circuit would be necessarily traced through a connection between contacts 29 and 30, and itwill be remembered that upon-the depression ofthekey 52 ats'ubstation 202 the operation of the electromagnet 2 caused a separationof'the said contacts 29 and. 30. A, similar circuit as thttgmdffop substation 201 conld'not be tracedfo the substationf203 and the remaining ubstations upon .the line, for the reason t at the circuit through the a wire for these m reremotestations is not completed throng 'the loog entering the nearer substation 201 until t e operatlon of the mechanism caused by the current-flow through the electromagnet 2 of substation 201, it being rememberedthatthe change of connection Aof the contact 29 is not brought about until the' breaking of thissettin -up current at the' central station. vIt shou d be -noticedffur- ".thermore, .that in this setting-up operation the --key 73 connectsthe battery 72 with the apparatus in such a direction that the actuatlon of the yarmature associated with the electromagnet 6 is not bro ht about. Therefore upon vthe operation o the key73 none of the switches associated with the electromagnet Gaisoperated.

The first' closure of the springs' 73 with their associated contacts and the 'subsequent release thereof causes the oundconnecton I G to be thrown ofi from t e substation'ZOl, and at the same time' theloop through this substation is. closed by the connection of contacts'29 and33.

' The second manipulation of the key 73 would cause a. similar change in the Acircuit connections at tsubstation 202 had not a simi- 'lar chan ebeen already brought Yabout through t e agency of the electromagnet 2, due tothe manipulation of thekey 52, Vlocatedat s'ubstation202. Thereforethesecond -manipulation of the springs 73 causes an operation ofthe instrumentalities at the third substationx203., corresponding 'with the operation at substation 201, hrought'about by the first mani ulation of the-sprin s 73. Similarly, eaclii key 73 builds up the line-wire a tothel next 'succeeding substation, at` .the same time throwing off the ground connections for the successive substations.4 Thus. after a number of manipulations ofthe key 73, corre.- sponding to the number of stations on a party-line, all the grounds have -been thrown off and the-.subscriber 202 is alone bridged across the metallic lines a and b. The o era tor thereupon releases the'key 62, whic has been depressed during ythese bperations, whereupon.hercord-circuitis connected with IOO IIO

successive manipu ation of the.

the metallic line, across which the substation a paratus is bridged in a manner familiar to t ose skilled in the art. i

The subsequent operations of ascertaining the subscriber with whom` conversation is desired-and the callinscof` the called subscriberneed not be described.4 A It may be well to here point out the fact that after the vbuilding `up of the fline, as above described, all the' lo, ground connections have been thrown ofi, so that no othensubscrlber on the same lline can secure the closure of his circuit between con-i tacts36 and 37which, it will 'be seen, is absolutely necessary in order to connect his telel phone instruments with the line. It is thus the bulbs 2 6. Upon the completion oftheo conversation between substation 202 and the called' subscriber the operator will receive a disconnect-signal, dueto the current-from a ringing-generator. -Before removing her plug from t e j ack it is necessary that she restore:

all of the subscribers selective apparatus-to lits normal position. This she does by sending a battery-,current over the two limbs a andbofthe telephone-line. It will be seen 'that in the alternate or built-up condition of the selective a paratus all of. the electromagnets 3 are bri ged across the metallic lines, Athe electromagnet 3 being normally andcontinuously connected with the b wire and in the valternate condition being connected -.throughcontacts 32 and 29 with the c wire.

Referring more particularly to 'Figs 2; 3, -end 4; it will be seen that the energization of this electromagnet 3 will cause upon the-re- -verse stroke a one-notch rotation of the spur- 5o- Wheel 12. The tail 26 will be in its'alternate position,as best shown in dotted lines inl Fig.

4. Thus upon the forward impulse of the spur-wheel the spurtooth will disengage the ttail 26', thereby allowing the bulb to drop I 5'5' back into itsnormal position. Similarly, the.

impulse imparted to the spur-wheel after the energization of the electromaghet 3 will cau seaspur of the wheel 12 to depress the tail40,

thereupon raising the detent-cam 39 to a A6c point where the detent 10 can retain thebu'lb m its normal position. Theroperator sends this restoring-current over the two limbs of the. metallic line by depressing both of the keys 62 and-64 and 'thereupon operating the 65 springs 73g. Thus the battery 72 is` connectdesires to'calll a 'given substation upon a three, 4and four upon the-line. It will also be l reverse direction, thereby causing. the operaed through the cord-strands 61 and 63 with the metallic line-Wires. Uponthe resteration 'of the'selective apparatus the operator .withdraws her plug from. the jack.

It will be seen that in thatstation or in those stations in which the bulb 34 has been tiltedirom its normal position-the restoringmagnet 3 when energized by the restoringcurrent from the central station will restore the said bulb Sito its normal position, and in 7 5 all of the stations the actuation caused by the restoring-magnet-will restorel the bulbs 26 back to their normal position:

Coming now v"to the case in which central given party-line, the operator first plugs into the-jack corresponding to the said party-line. She thereu on depresses the ke 62 and manipulates t e springs 73' a number'of times, v one less than the 'number of the substation 'to 8 5 be called upon the part -lin'e. Thus if the operator wishes to call t 'e subscriber whose station' the fifth remote from the central station she will manipulate the key'73 four times. The-circuit set up by the manipula- 9o tion-of this key has been previously traced, it

bein'g'remembered that a single operation of the said sprin s causes the break m theloo at the first suliscribers station to be close alsothat the same manipulation throws off the ground connectiony at the first substation. The three succeeding manipulations, 'off-this; keywill then successively produce a similar change in theapparatus at substations two,

`IOO 'remembered thatl the'. manipulation of the springs 73 does not permit 'current hollow.

rough the electromagnet 6 in such; a direction as toattract the armatures A9;; However, after' four manipulations of the springs- 73 the lifth manipulation is ofthe springs 74, whereupon the selecting current is .sent through the fifth subscribers apparatus'in the tion of his polarized armature 9, Thus the fifth subscribers telephone [setis bridggedV -across theline. At the same time 'or immei. diately thereafter the break in the line 'a't his substation-is buil-t up. -After this manipulation of the. springs-74 the' succeeding currentv 1i 5 impulses are sent out by manipulations of the springs 73, thus causing the remainder of the substations on the .line to' have' their ground connections thrownI oil. Substation ve' is then alone bridged across the liiie in condition' to carry on conversation with a -calling -subscri er, who, it may be assumed, has previously been connected with the other side of the'operators 'cor'dcircuit. Under these circumstances 'the line is b uilt up in the same way 'as it wasfunder the condition in which the subscriber-on the panty-line was calling, with theexception that instead of the actuation oithe armature 9 .being controlled by the key 52 it is controlled -by the central opA 13d -Iro vto

erator bvthe reversal of the direction of th siredconnection.

deed, does not know which particular station is the calling station. on a party-line; but

, when a calling subscriber asks for a connecltion with another subscriber. on the' same the' callin are locate v ing up "abroken line, she is enabled to know?? which of thel building-up impulsesare to be p'arty-lineit becomes necessary for the opera-j tor to know the substation-number of bothV and thecalled subscribers who?I on the same line. Thus in build# reversed in direction, so as .tofonnect the two desired subst-ations with the line-wire b.' l

It-will not. be necessary for a proper understanding of .the operations to vtrace the' circuits employed, it being apparent that the operator upon receiving a.- line-signal will build upthe broken line, as usual, andthen inquire for the connection desired bythe call-.

in subscriber. Upon learning 'that the c `led subscribers station is located on the same party-line as that of the calling sub-` scribr, the operator will first restore the partyline to .its normal condition, as has een previously explained and will thereafter send outthe setting-up impulses, as hereinbefore explained. In building up the line, however, impulses inreverse direction will be.

-employed corresponding in number-with the two substations to be connected for conversation. Thus upon buildin f up the line the two required subst-ations will have their tele-v phone instruments connected by the corresponding'reverse impulses with the line-wire by The restoration of the mechanism connected with the party-line upon the completion of the conversation is accomplished as heretofore explained for the other conditions of oper ation.

Thus it will be seen that our invention rovides a partyline telephone system w ich overcomes the defects in existing systems and at the Sametime introd uces' material advancesover the systems of the prior art.

Since theselective apparatus employed in our lsystem is not dependent upon the strength or polarity of the currents employed nor upon what'may be termed marginal currents,`the instruments are not delicate in their adjustment, and therefore subject to false operation. The instruments, furthermore, do not depend upon synchronous operation, and therefore cannot introduce difficulties by getting out of'step one with another. -The selective apparatus is not normally bridged lacross the selcctinU-circuit, as

Under normal conditions v the central 'operator does not inquireand, in#

inmanypartyd ine sys tems, whicl thereby i troduce dihculties on account ofthe different resist-ences encountered. by currents flowing from the'central station to various substa l tions. In this connection it `will be seen that since only one of the selectingeicetromagnets is operated at a tlmeonly asmall amount of.

operating-current is necessary.

In regard to the bridging of the restoringelectromagnets across the lne, which are then o erated `in parallel,` vit may be pointed outl 't at if for anyreason thecurrent strengthia not'suiiicien't to operate the inecha'nismat ail of the stations only those restoring-magnets which are not roperlyoperated remain in the circuit.v Tlierefore -a. second restorin impulse, on account ol the largely-decrease number ofaths, is sure-t operate any of the magnets which fail-'f-operation on` the first i y ulse.. Y 'ix'l'llhe mercurytubefswtgehes which are.

preferably-employed. are of decided advantage over switches heretofore employedv on account of vthe fact that the contacts are not" subjecttodeterioration on'account of their exposure to atmospheric conditions,- and our present system proavides a further great aid- 'vantage, which, ndeel,would"be present whetheror not 1the merc -switcheswere employed .in that theselecin'g-eurrents are never broken the switches'at the substa-- b. tions. While the circuit connections are, ini deed, changed at the'substations, these cir.

cuit changes are always made-npn the reverse stroke of the o erating mechanism when.

no currelnt is actua ly flow: therethrough;

'Thus all the undesirable res ts caused by a IOO frequentlyfrecurring electric sparkbetween switch-contacts are done away with.l

It will be seen that our stem provides what may be termed a double -lock-out feature in that upon receiving a signal at the central station the o'perator plugs into the lineej ack, whereupon the ground connection through-the line-drop is broken. This of ,course at once prevents all the subscribers;-

except the one .who has previously depressed his key 52, from getting thegrcund connection through the battery 57, which is necessary in ordei to` operate their switches c'oi necting in their telephone apparatus. thev broken line has been set up bythe cen? traloperator the connections between con;

.tacts 30 and 29 are 4broken at' all of the'sub stations. This of course introduces a second break inthe circuit necessary for a subscriber to get his telephone apparatus connected with the line. Thus by this double break in the circuitwe introduce what may be termed a double lock-out"` feature.

In connection with the lo'ckoutfeature our system provides a distinct advantage in that the line. and all the ap aratus .connected After yizo therewith are directly un er the .controliof the'central operator alone-that is to say,

p the operator her power togive I 4o i A Our invention maybe advantageouslv employed in connection with a metallic tollline connection only to those subscribers Whom she desires 'to connect, and she is' enabled at any time to out off any subscriber who 1s monopolizing the line. This is also a desirable '5 feature when a party-line is also used for tollic improved system is an exact line pur oses, it being customary to alloiv the toll-line business to supcrccde that of the local substations. i

The apparatus used in the o eration of our duplicate at all of the substations, the substation selecting apparatus not being set oradjusted in any way peculiar to its osition or number on 'the 'party-line, and, 1n eed; the suhstations are notindividually adjusted even to the extent of a resistance-coil. In so far as the instal- Alation'oi? our system is affected by present ex isting apparatus it a Wortlyvfeaturenin economical installation that any form of telezo phoni or. signaling' apparatus whatsoever may be associated ywith our selective devices.

its fvillbe apparent from the foregoing description of one embodiment of our invention,it will be seen that the subscribers tele# hone apparatus is normally disconnected rom the-telephone-line, it being then only necessary to connect with the line of that sub-` sdribers. telephone set which is .to be rn.

played for conversational purposes. This f ca- 3o ture presents a decided advantage over those systems in which all of the telephones are normall'y connected with the line and all of which must be disconnected therefrom save that telephone'which is tobe 'used inconversatiom Incidentally'it4 might be pfointedout that the condensers 59 are normally disconnected from theline. They are therefore not subject to punctures due to lightnin discharges, which is an iinpolrtant factor in lie operation of a long party-line.

ruiming through and betWee'n a number of 'central sta-tions, it 'being now a lcommon practice for an operator-say at a principal office at the end of a tollline-to have a connection only to the first of a series .of central stations connecting therewith. In order to'v secure connection, With a more remote cen- 4trallstation, it is necessary for tlie operator at the principal sltation to ordertlie operators at the subcentra stations to Nmake the`connections intervening betWee-n'the successions 'of the otherwise continuous metallic line. Our invention as applied to such toll-lines enables the principal o erator to have control .over the connecting evices attlie'subcentral stations, .whereby she can secure connection with any desired central station.

While we have shown and particularly described one preferred embodiment of our'.in

vention, it will be evident that many changes and modifications therein might-profitably employed Without departing' from the" spiritof our invention. We therefore do not `65 Wish to limit ourselves totheprecise disclosure herein set forth; but,

Having described our invention, We claim as new and 4desire to secure by Letters 'Patentl v 1. lilie combination with a centralstation, of a line running from.said central station broken at a series of substations, electromag# 'netic mechanism controlled romthe centralstation'adapted to'build up a non-inductive electrical path through said 'broken ine to anydesired substation, electric signalingapparatus 'at each ofsaid substations, a second ineconnecting all of said substations with the central station, electromagnetic mechan.

ism lat' each of said substations controlled vfrom said central station 'adapted to connect said signaling apparatus in circuit with said.

lines,'and means at each ofsaid substations affording 'a secondary control over the electromagnetic connecting apparatus at the corresponding. substation, substantially as de-A scribed. i t f 2. The combination with a ce'ntral station,-

of 'a line running from said central station broken at a series ofisubstati'ons, electromagnetic mechanism controlled from the central station adapted to build up a non-.inductive circuitthrough said vbroken 1ine to any desired substation, a return-circuit from said substations to said `central station, velectric 3. The combination with-a central station, A

of a line running from said central station broken ata series of substations, a return-circuit from said substations to said central statioii, electric signaling apparatus at each of said substations, a second line connecting alll of said substations with the centrall station, electromagnetic mechanism at eachof said substations controlled from said central station adapted. to connect thesaid second line with the signaling :apparatusat any vof said substationaand means at each of said lsubstations affording a secondary control over the electromagnetic connectingap'paratusat the corresponding station,- su described.-- t

.4.V The combination with a central station,

of a line running from-said cential station brokenat 'a' series of'substations, electromag#A *netic mechanism controlled'rom the centrall station' adapted' `to build up a n onfinductive -stantially as' circuit through saidbrokemline to any de sired substation, other electromagn etiumech anlsm controlled frogn said central station nalingapparatus ateachof said substations,

adapted to break saidfelefctric circuit at said substations, a return-cncuitirom sain' substatlons -to'sald central station, electric siga secondline connecting all of said substatio'ns the central station, electromagnetic mechanism' at each of said substations controlled from said central station adapted to connect the said second line With the signaling apparatus at any of said substations, and means at each of said substations afford:- ing a secondary controlover the electromagnetic connecting apparatus at the corresponding station, substantially as described.

5. In a selective partydine system, the combination with switching mechanism comprising a mass of mercury for making or breakin electric circuits, of electromagnetic 'means or actuating said mechanism, and means for causing current to new through said electromagnetic means, the op eration et, said switching mechanism being accomplished yWlroiljyf upon the cessation of said current-flow,

- substantially as described.

' stantially as described.;`

' `of a line runningfrom lsaid central station 6. ne combination with a central station,

of aline running iromthe said central stationl broken at a series of substations, electromagn 'metio-mechanism adapted to be actuated by suitable electrical impulses to build up a noninductivecircuit through said broken line to any desired station, 'other electromagnetic mechanism adapted to be actuated bye suitd able electric impulse to break` said electric circuit at said 1substationa return-circuit vfrom said substations to said centralustation,

electric signaling apparatus at each of ysaid substations, a second line connecting all oi. said substations with the central station, electromagnetic mechanism` at. each of said substations adapted to be actuated by an v.electric impulse oi" suitable polarity to connect the said sedon'd line `With the signaling apparatus at. any of the substations, means at each of the substations affording a secondary control @fthe electromagnetic connect-4 ing apparatus 'at thecorresponding station and means proydedat the central' station whereby the? operator-may control said electromagnetic mechanism by causing suitable electric impulses to'liowtherethrough, sub

7. The combination with a central station,

broken at a series of substations,v neutral electromagnetic mechanism controlled from the central station adapted tobuild up a non-inductive electrical path through said broken line to any desired sullstaftion eleptrio signala aratus at eac 'o sai su stations, a loudpline connecting all of said substations lith 'the central station, electromagnetic trolled from said centralstation'adapted to with two of said lines, an means at each oi said substations affording a secondary con trol -overthe electromagnetic connecting a paratus at the corresponding substation, substantiallyits described.

8.. The combination With a central station, ofa line running from said central station broken at a series of substations, electromagnetic mechanism controlled from the central station adapted to build up va non-inductive electrical path through said-broken line to any desired substation, a return-circuit from said substations to said central station, electric signaling apparatus at each of said substations, a second line connecting all ol said substations With the central station, electromagnetic mechanism at each of said substations controlled from said central station adapted to connect one of said lines with the signaling apparatus at any of said substations, 'and means at each of said substations mechanism at' each of said substations con- 6 adording a secondary control over the eleci tromagnetic connecting apparatus at the corresponding station, substantially as described,

9; The combination With a central station, oi a line running from said. central station broken at a series of substations, electromagnetic mechanism controlled from the central station adapted to vbuild u a non-inductive electrical path through said broken line to any desired substation ,other electromagnetic mechanism controlled from said central station adapted to break said electrical path at .said substations, a return-circuit from said substations to said central station, electric signaling apparatus at each of said substa tions, a second line connecting all of said substations With the central station, electromagnotie mechanism at each of said substatons IOO controlled from said central station adapted Y to connect one of said lines with the signalingv apparatus at any of said substations, and

means at each of said su'bstations affording a secondary control over the electromagnetic connecting apparatus at the corresponding station, substantially as described.

10. The combination with a central station, of a line running from said central station broken at a series oi substations, electromagnetic mechanism controlled 'from the central station adapted to build up a non-inductive circuit through said broken line to any desired substation, a return-circuit from said substations t0 said central station, electric signaling apparatus at each of said substations, a second line connecting all of said substationswiththe 'central station, electromagnetic mechanism at each of said substations controlled from said .central station adapted to connect` said signaling apparatus in circuit with two ci said lines, and means at leach :said substaticna IIO affording al secondary control over the elec- 'tromagnetic connecting apparatus at the corresponding station, substantially as described.

11. .The combination withacentral station, v Aof a line runningffrom=said central station,

broken at .-a seriesofzsbstations, a return- .circuitiroxn said lsubstations to -said central station,.electr1c signaling apparatus' at each cffsaid substations, a Second line connecting all of said. vsubsi'latioils'with y.the central station', electromagnetic mechanism at each of said substations controlled from said centralI station adapted to connect said signalingapparatus in circuit 'Withtwo of said lines, and means-at each of said substations affording a secondary control over the electromagnetic connectingv apparatus at the corresponding station, substantially as described.

12. In a selective party-line telephone system,'the combination with a central station, of a line Arunnin therefrom to a series ol. substations normal ybroken at cach of said substations,signalingl apparatus at each of said substations normally disconnected-'from said operator may .connect the signaling apparatus at a plurality of said substations in vcircuit simultaneously with saidnfbroken line,`

substantially as described. l

' 14. In a selectiveparty-line'telephone system, the combination with a centrall station, of lines running from the central station to a vseries of subStatiOnS, one of said lines bein normally broken at each substation, sigf4 na ing apparatus at each lsubstation normally disconnected from said broken line, and means controlled from each substation and from the central station, whereby the corresponding signaling apparatus may be connected with the broken as described.

15.l In a selective party-line system, the combination with. a central "station, of lines' 'running 'from the central station to a series of substaticns, one of said lines being normally broken at each substation, signaling apparatus at eachvsubstation normally disconnected from said broken line, and means primarily controlled from the central station whereby any substation signaling -apparatus imay be connected with the broken line and lsecondarily controlled from each substation,

whereby the correspondin signaling a paratus may be connectcdwit the broken ine, substantially as described.

16. In a selective party-line System, the combination' with a central station, oflines' running from the central station to a series of substations, one oi said lines being norvmally broken at each substation, signaling apparatus at each substation normally dis- 'controlled from each substation, and from the central station, whereby the corresponding signaling apparatus may be connected with the broken line, substantially as de scribed.

17. .In a selective'party-linesystem, th combination with a central station, of lines running from the central station to a series of substations, one of said lines being norme, substantially lconnected from said broken line, and means l mally broken at each substation, means for Y building up lsaid broken line through any number oil? said substations, signaling appa ratus at each' substation'normally discon nected from said broken line, and means v'controlled from each substation, and from the central stati-onf whereby the correspondingsignaling apparatus may be connected with said broken line,'substantially as described. In witness whereof we liereuntosubscribe our naines this 6th day of October, A. D. 1902.

'ARTHUR F. POULE.I

` FRANK B. HALL.

l/Vitnesses:

MINNIE K. COCHRAN, LANDY Srsson.

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