US1131455A - Telephone system. - Google Patents

Description

H. M. WRIGHT.

` TELEPHONE SYSTEM.

APPLIOATION FILED MAR.12, 1914.

' Patented Mar. 9, 1915.

4 SHEETS-SHEET L H.` M. WRIGHT.

TELEPHONE SYSTEM.

APPLIOATIN FILED MAR.12, 1914#v 1,1 31,455. Patented Mr, Q, 1915.

4 SHEETS-SHEET 2'.

IGHT.

ATlfullrom; SYSTEM. APPLICATION FILED MAI\i.12,1914.

H. WR

Patented Mar. 9, 1915.

Q SHEETS-SHEET 3.

A IN1/Enron @wiwi/@aya WTNESSES Mal; /fLA ATTORNEYS H. M. WRIGHT.- `TBLBPH0NE SYSTEM.

APPLIGATION FILED MAR. 12,1914.

Patented Mar. 9, 1915.

4 SHEETS-SHEET 4.

ITED STAWENT FFCE- HARLEY MELVIN WRIGHT, or DARLINGTQN, OKLAHOMA.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Mar. a, 1915.

ApplcationledMarch 412, 1914. Serial N c. 824,124.

To all whom t may concern.'

Be it known that I, HARLEY MELviN VHIGHT, a cititzen of the United States, and a resident of Darlington,.in the county of Canadian and State of Oklahoma, have made certain new and useful Improvements in Telephone Systems, of which the following is a specification.

i lockout system in which the subscribers stations are not provided with hand controlled selective switches. Fig. 2 is a diagram constituting a contination of the lockout system just mentioned in connection with Fig. 1, and showing a number of subscribers stations, 'certain parts being omitted for the sake of clearness. Fig. 3 shows fragmentari1y,'a line provided with the lock out system just mentioned, and illustrated the comparative condition of the stations locked out and thus connected. Fig. 4 is a plan View of my improved electrically loperated switch as constructed for general use invarious forms of my system. Fig. 5 is a section on the line 8--8 of Fig. 4 looking in the direction of the arrow. Fig. 6 is a section on the= line9-9 of Fig.

,4 looking in the direction of the arrow.

operated switch employedl at" the central..

station; yFig. ='12 is a section on' the line 16.-16`of Fig.1f11,`,looking in the direction of the arrow.v 'Fig'. 13. is a section on the line 19-19 of Fig. y12 looking vin the direc-'- tion of the arrowr` '1s a detail being a. section on the line 18-18 of Fig.. 12 and showing one of the contact members carried upon the switch arm in said figure. Fig. 15 is an elevation of the handoperated 60 switch used at the central station and appearing in Fig. 11.

In Fig. 1 the `line wires are shown at 21, 22, and at the central station these -line Wires are connected with short wires 23, 24. The wire 23 leads to a line drop 25, and in series with this drop is a wire 24, leading toa contact 24a. This line drop is of the ordinary construction commonly known infy this art. A movable Spring 24h constitutes 70 one member of this cont-act, which normally remains closed, as may be understood from Fig. 1.- Two conducting cords 2G, 27, are respectively secured to contact members 26a, 27a, forming a jack connection. E A 75 I wire 26b is connected with the contact *26"* and .also with the wires 21 and 23. The conducting cords 26 and 27 are also connected with contact members 28, `29, forming a part of a ringing key at the central 30 station. This ringing key is provided further with contact members 30, 31, 32, 33. `Wires 34. 35, are yconnected with the contact members 31, 32, and are also connected with wires, 36, 37. The line drop 25 is 35 disconnected-'only when the central operator inserts either the calling plug or the Aanswering `nlug into the jack., Whenever the cords 261and 27 are connected with the .jack. .thelin e wire 22 is connected with the 150 conductor 27 and the contact 24" disconnects the contact 24a, whil'ethecord 26 isV connected to the line wire 21. The wire 36 is connected by a wire 38 with a winding 41 forming a part of an ordinary clearing 95 out drop 40 located at the central station. The winding 41 has suchV impedance and resistance-as to make it most effective, and still prevent the talking currents the ire- .ouency of which is comparatively high) 109 from passing through it; Athe .winding 41 is. connectedby a wire 42 with the wire 37.

A listening kev of the central stationv is shown at 44, and connected with this listen- `.ing key are .two wires 45, 46. which lead to 105 the operators set. Connected withthe contact member 30 is a wire 47. .v

A wire 48 is connected with the' wire 47 and leads to a hand controlled .switch 49 located at the central station, and shown-more im particularly in Fig. 15. Connected with the contact member 33 is a-wire Qwhich is lgrammaticallyl in Fig. 1. and is hereinafterl connected-with a wire 51 leading-tothe.

switch 49. A wire 52l is connected `with the wires 50, 51, and with al push button 53, the latter being normally open.- Another wire 54 is connected' with the wirs 47, 48, and.

with a contact` 55 which is normally open. A wire 56 is connected with this contact and withanotherwrrire 57,v the latter bei-ng connected to a generator 58. This generatoris adapted for producing bothalternab, ing and direct pulsating'current. vThe conf tacts 53 and 55, together constitute' a double-contact push button for controlling the alternating current as supplied to the line.

.A wire 59 is connectedwith the wires. 56, 5.7, l 'and communicates, through the medium' of the hand switch 49, with 'the generator 58. The switch 49 is always connected-to the alternating or direct `circuitofthe generav tor, but does not energize theline until the switch arm is moved. angularly forv the pur-y pose, soas toclose'a particular set-'of clon. A tacts as elsewhere described.. A Wire 631s' connected with the ground 64 and with the .switch 49. The electricallyoperated switch is shown at 65. This switch is shown diamore particularly described as-to. itsV me.

chanical structure, withV referenceto igs.,

d, to 8 inclusive.

' Thesuhscribers magneto is shown at, l66

` tact member 72 a wire 73 leads to the primary winding 74 of the induction coil, and 'from this winding a wire'76 leads to the llocal battery 671.

The primary winding 74 is in inductive relation to as econdary windingji'. The subscribers switch hook is shown at 77 and the receiver. normally hanging thereon. at '78. Connected .with the switch hook 77 is a wire 79. .A wire 80 leads from the receiver 78'to a condenser 81, and connected with the latterisa ywire 81K. A short wire 83 connects the wire `81 with the line wire 21, and

with a vwirei.. Connected with this wire is a wire 82 which leads to the electrically operated switch 6 5'. A wire 85 is connected with the wires 82, S4, andleads to vthe mag# neto 66. A wire 86y is connected with this ma gneto and with a short wire 87. the latter being connected :with the line wirej'22m- A wire 88V is connected with the] wiresS; and 87, and with the electrically operated'switch 65. lVires 89, 90, are connectedw'tli this switch in a manner hereinafter described. Connected with the wire 90 are .two wires 91, 92. and-connected with the wire 89 are two wires 93, 94. The manner in whichthe wires 91,92, 93,94, and various otherwires .manege a .arecoiinected with the swi'tch set'forth i below.

A wire 951s connected with-thesecondaryi vvwindiifig 75 and with a contact-spring 127.

A wire 97 is connected with the receiver'78 v and with a contact spring 128,' these two contact springs being mounted upon the electrically operated switch y'65, and more particularly described below in connection with the mechanical description of' said switch. A wire 99 is connected at each. of

its ends to said switch, as described below.

A wire 100 is connected withy the switch and with the'ground. y

The mechanical construction of the electricallyoperated switch is' shown in Figs. 7

to 11 inclusive. Thereare sixv windings 101,

102, 103, 104, and 106: Thetwo WindingsV 104, 105, are mounted concentrically upon a. singlecore 107 which is-made of soft Norway iron, adapted topolarize easily by magnetic induction.r Another core 108,

similarly constructed and .also vreadily.a mag- `netized, carries a singleiwindinglOG.

A coref109 sixnilar to the core 10'8 carries the single winding 101, vand a core 110'similar tothe core 107 carries the two- windings 102, 103 disposed concentrically. The vvarious parts are supported upon a base 111'.

Four yokes 112, 113,114, 115, are provided for facilitating the completion of the magnetic circuits4 through the `respective cores. The yokes 113, 114, are mad3 of soft Norway iron thoroughly annealed. A The v.yoltes 112 and 1,15 vare made of tungsten steel permanently magnet-ized, and having their south-seeking poles. extending upwardly and thusv by ma'gnetic'induction rendering the cores 107, 110, magnetic, the north-scelting poles of these cores extending upward.-

The .yokes are supported upon plates'116,.

-11,7 `of non-magnetic material secured to the base 111. (Two 'frames 118,. 119, made of noni-magnetic material are mounted upon the supporting plates 1-16, 117. Journaled in the frame 118 is a shaft. 120, vand a shaft 121 is journaled partly in 'the'frame 118 and partly in the frame 119. Mounted rigidly upon the shaft is a polarized armature 122,-.and mounted upon this armature is a finger 123 made of non-magnetic material,

preferably brass.

Secured upon one end of -the finger 123 l is an `armature 124 having the form of a disk and made of annealed iron so as to be unpolarized. The armature 4124 extends through an' opening 125 made for the purpc'se inthc yoke 113. Mounted -upon the supporting plate 11.6 is a bracket 126. Supported by thisV bracket are two contact springs 127, 128, the spring 128 being uppei-most. Above the contact Vspring 128 is a. projectingtongue 129, constituting an.- other contact spring.l The'contact springs 127, 128, .are insulated from each other, and

.oneness l 127 whenever the armature 122 is attracted .from the Contact member upon the underside of the armature 122 is a from its normal position. Each time the armature 122 is attracted as just stated the disk 124 is raised relatively to the core 108. The diskA 132 and the stirrup 131 lare insulated frcm the contact spring 128. The purpose of the stirrup 131 is to trip the disk 132 against the tin er 123 whenever the stirrup 131 is actuate as hereinafter described, so as to disconnect the contact member 128 127. Secured leaf spring 133 made of German silver, this spring at its free end resting upon the core 107.

Mounted upon the shaft 121 is a polarized armature 134, and secured upon the underside of this armature is a leaf spring 135, the free end of which rests upon the core 110. This leaf spring is made of German Y silver, and tends to hold the armature 134 in normal position; that is, in such position that the armature 137 rests against the core' 109.` Similarly, the spring 133, which is of German silver, tends to hold the armature in l normal position,-`so thatthe armature 124 rests upon the core 108.

A. finger 136 made of non-magnetic material such as brass is carried by the armature 134. A disk shaped armature 137 is carried by the finger 136 and extends through an opening 138 in the yoke 114. The shaft 121carries a crank arm 139 which extends through the yoke 131. The two tingers 12.3, and 136 are held in position by screws 140, 141, extending directly through them. The fingers are bowed slightly at the points where the screws extend through them. By turning the screws the fingers are-iiexed so as to shift the positions of the armatures 122134, slightly in relation to the respective cores with 'which these armatures are associated. The screws 140, 141, a-re thus `used to adjust the sensitiveness of the armatures 122, 134. The armature 122 carries a chipper 142 mounted rigidly upon it andexteuding downwardly into proximity toa gongvlli. so arranged that when the the. gong is struck by. the-clapper and thus murature-122 is attracted by the core 107,

' sounded.v ""lhe- .armature 134 carries a clap.-

i' per 144 ysecuredrigidlyto it and extending downwardly in close.4 proximity to a small gong 145 so positioned as Vto be struck by the clapper 144 as the latter is swung from its normal position as the armature 134 is actuated. See Fig. 6. The armatures 122 134 are formed as indicated in Figs. 7 and 8, .the armature 122 being provided with a wedge shaped groove 122, and the armature 134 being similarly provided with a wedge shaped groove 1341. These grooves are merely for the purpose of facilitating the connection of the lingers 122, 130, with the respective armatures, and are not in all instances essential.

Mounted upon the base 111 are a number of binding posts 147 and connected with thev latter are a number of wires 147a, the latter being adapted for connecting them with and disconnecting them from the various windings, in order that the windings may be arranged diii'erently at the respective subscribers stations. To facilitate this purpose I also provide short wires 147D, which extend merely from one binding post 147 to another: By aid of the wires 14", 1471, I can readily disconnect the windings from the binding posts and connect them up again in al different order.- The purpose of this arrangement may be more readily understood by reference to Figs. 1 and 2. In Fig. 1 I show the windings as connected with various wires in the most convenient manner lto adapt the subscribers switch for a par ticular one of the stations; or in other words, as subscribers station No. 1. In this in stance the winding 103 is connected with the wires 82 and 89; the winding 102 is connected with the wires and 88; the winding 101 is connected with the wires 99 and the windings 105 and 10G are connectedv with the wire 99; the winding 106 being also connected with the wire 94; the winding 104 is connected with the wires `91, 93. As a re-4 sult of the connections just described, the4 windings 104,105, and 10,6 are `essentially arranged as a delta, the corners of the delta being connected respectively with the windings 101, 102 and 103.

The connections of the various windings relative to each other at subscribers stationsnurnbered 2 to 10 inclusive areshown v in Fig. 2. The connections of the windings l 101. 102, 103, are never changed relatively to the line wires 2.1, 22 and the ground wires 100, and are consequently alike at each of the respective subscribers stations. The interconnections, as between the windings 104,

105 and 106, howevenare at the variousstations made as shown in this figure. It will be. understood, however, that the relative positions of the various windings are not changed, as the windings are not moved of the windings 104, 105, 106 being altered by suitably Aconnecting the ends of these` relatively to each other. the virtual positions nected at subscribers At thex'subscribers stations numbered 7, 8,

A' 9 and 10, the' windings 104, 105,,and 106. are

arranged to delta connections. Where there are only six subscribers stations the windings in question-can readily be delta connected, Vbut .'where the number of subscribers stations is in excess o'f six, the additional stationsthus added,.that is,'those numbered 1n excess of six, are best" provided with star connections. for `the reason that the number ofdelt'a con-1 nections possible; is limited. The same wind- `ings and other mechanical parts are used atV all of the stations. `When the star connections are employedthe windings should, be

' made of larger size or some other provision should be' made for equalizing and apportions as Just tioning the relative resistances offered by the several subscribers stations.

- My purpose in .forming the windings 104, 105, 106 into various star and delta permuta.-

lock-out mechanism of one subscribers station to be operated while that of another f and also for controlling'the connecting'- and.

.central station,` the relative arrangement ofA station is left idle.v `l/Vhen 'two subscribers stations arenn communication with each other, through the agency of the central stal tion, as hereinafter described, these two stations must be free to communicate'with each other and all other subscribers stations onthe Iline must be locked.: For this purpose,

disconnecting mechanism of the respective subscribers stations, and for the further vpurposeof enabling eachsubscriber to call any other subscriber without disturbing the vthe winding as abovedescribed is essential. The manner--in'which these 'results are accomplished is set forth below.

' Iwill now describe the mechanism of the switch 49 usedat the centralstation for the purpose of controlling theparty lines. This switch49 is provided with a movable switch arm 148 carrying two contact plates 149, 150, which are insulated from the `switch yarm and from eacli other by a plate 148a of insulating material. The contact plate 149 is provided with two contact tongues 149, and

i' the contact plate 150 is provided with three contact tongues 150. I therefore convenlently refer' to the contact plate 149 as a double contact plate and to the plate 150 as form star connections instead of described is to render .the sub-4 scribers stations selective and to enableV thel 199, v'contact members 200 201 v peg 202'contact members 203, 204, 205, 206 pegs 207,

208, contact 'members`209, .210; peg-'211, con,-

members from 215 'to 229 inclusive and a single peg `230 of insulatingmaterial. As the' switch arm 148 is `movedl angularly around, the triplecontact plate 150 are brought into regf. istry 'with .various radially disposed groups of the contact members above designated For instance, when the switch arm 148 is moved angularly upward according to Figa 1, lnected together by .the. double contact plalte '149, and the contact'members 183 and -2115 are .broughtv into communiation through t 4 e medium' of the triple contact plate 150. l

The outeror sector shaped contact 'members 151 to 166 inclusive, because of their greater length measured in the -arc oa circle, are engaged slightly prior to the en- The switch 49 is protact member 212; peg 213, and contact member 214. Another row contains contact e5. double contact plate 149 and the the contact members 151, and 167 are conagement of cthercontact members disposed 1n va rowradiatingjfrom' the center of` r'otation of theswitch arm. For instance, if

.according lto Fig. 15 the switch arm 148 be swung-u}' 9w; irdlyV over the contact members 215, 183,167, and 151, the double contact plate 149 first engages the contact member i 151 and then engages 167, and the triple contact member 1 50 brings the contact members 183, 'and 215 into metallic communication at the'sameinstantthat the double con-- l tact member' 149 engages the contact member 167.' The various pegsof insulating material shown in Fig. 19, such as those numbered 199, 202 and 207, have n o electrical function and are merely employed to insure uniform- I'the following contact members .215, 216, 217,218, 155, 15e, 157, 222, esa. Q24, 225. 226,

1227, y 228 and 229. The wire 59 is connected insinua with the following-contact members: 183,

184, 185, 186, 187. The wire 48 is connected with the following contact members: 200, 153, 154, 219, 220, 221, 15s, 159, 1160, 161, 210, 212, 214. The wire 51 is connected with the following contact members 151, 152, 201,-

and 166.

The various stationary contact members shown in Fig. 15 are arranged in radially disposed groups, each group representing a subscribers station. The subscribers station No. -6 is represented by ve contact members 156, 172, 188, -204, and 220, as indicated by an appropriate legend on Fig. 15. `The various other subscribers stations numbered 2 to 11 are similarly represented by groups of contact members as indicated by appropriate legends in Fig. 15.

The legends just mentioned, and the respective rows of contact members associated therewith and referring to the separate subscribers stations, are used in calling the station connecting them with the line and locking out other stations not called. The

mM/contacts of station No. 11 when used in connection with a lockout systeml may be used for ringing the lockout bells: before connecting certain subscribers stations with the line-thus insuring secret service by locking off all subscribers before connecting the line with the stations of 'the party or parties desiring to talk secretly. Other legends,

I however, such as numbers 1 and 2, numbers 3 and 4, numbers 5 and 6, numbers 7 and 8, groups of contact members associated with themand referring to the different subscribers stations, are used only in connection l withthe act of restoring the line to normal condition after each secret conversation thereonrbetween row subscribers, and in thus -restoring the line to normal position, to ring a bell at each subscribers station in order to apprise the subscribers that the line is no longer busy.

The groups of contacts designated in Fig.

Nm 1513s, numbers 1 and 2, numbers 3 and 4, Jnumbers 5 and 6, numbers 7 and 8, numbers vso 9 and 10, are employed in connection with alternating currents, which are rendered available by simply swinging the switch arm 148 to its lifth position, or in other words, from its normal position to the contact member 155. The push button contacts 53 and 55 and the switch 49 are never used simul-V taneously, as they are employed independently of each other. The purpose of the push button contacts 53 and 55 is to supply alternating current to the line in order to ring the lockout bells; also, when used with party lines or with individual lines, to ring alternating current bells.

With .the form of my vsystem vshown'in 1 and 2, when a subscriber'wishesto tallz'to another and `desires the conversation to be secret, he actuates his magneto. The central answers and asks his number. The subscriber replies, giving his number and also the-number of the station he desires called. The operator then presses the push button, so as "to close contacts 53 and 55, This locks all of the subscribers stations off. of the line. She next releases the push button, swings the switch arm 148 to the number indicating .the calling subscribers station, .and then pressing upon the switch arm, she energizesithe line and this rings up the calling subscriber. She next swings the switch arm 148 to the number indicating the station of 'the-subscriber called for, and then pressing upon the arm she calls the party in question. `He answers, and the two parties desiring to converse secretly can do so. The

' eeotof these movements is `to connect both station of the subscriberlcalled, and to lock out all other stations. The. conversation being finished, the central operator swings the as to cause it to close the contacts which it controls. As it passes successively over the last five positions indicated at the right' of Fig. 1'5, the various subscribers stations are all successively brought into normal condi-v tion. The subscribers .stations are then connected .to the line by each connecting bell being rung with one short ring, the respective subscribers being thus apprised that the line is no longer busy.

The windings 104, and/106, at the different stations, are connected differently in relation to the line, as indicated at Figs. 1 and 2.` These )figures show how the - varions windings 104, 105 and 106, at the respective stations, are virtually shifted in relative positions, each grouping or shifting of these windings having opposite polarity connections for the windings 104 and 105, as indicated by the legends N and S indicated ,in Fig. 2. The opposing polarities are obi not polarized. Therefore, it ,responds to` currentV passing 'through-it in either direction, and it locks the disk-like armature in its operating. The locking-of the disk-like armature in its Vnormal position prevents movement ofthe polarized armature, so that the windings 104 and 105 are unable to actuate it. The only time, therefore, the bell can operate is when -njo current is iiowing through the winding 106, while the windings 104 and 105 are :energized by current owing through them-in such direction as to core carryingtlfie Findings 104 and l19.5. Theconnectioijis'fcrthe windings .101, 102

strengthen the 'induced magnetism in `the l and 103, controllingthe incitent or disconnecting bells, are alikeatallstations.

lnliigs. 9 and 16 v1 show ,a convenientgf,

, form of telephone boxsuitabieror 'holding j f the' variousxtures of :thesubscrlbers tions 'as above' described Theben or casing is shown at 389,the' lid ofthe box appearing l at 390.. A number of metallic `hinges are switch 1s mounted in the upper portion of the box as 4'shown more particularly in Fig. 13.

1 will now describe the operation of my system. .if .any subscriber lifts his receiver Jfrom the hook he'- will hear a click if the line 2 0 is not busy. When this is the case the subscriber has free access toy the line at all times. Incase of such emergency that it is necessary-to make a call even when the line is busy., this `may be done by 'ringing the central station and using. the code number of Athe subscriber calling.. This notities the central operator-'that the subscriber having the 'code number in question is ringing and that the casc'is one of emergency. The code numbers may conveniently be'arranged as follows z-subscrlbers stationv No. 1, one

l`short ring and one long ring; station No. 2,v

two short rings; station number 3,-,three short rings, etc., the idea being that each station has some distinctive ring of its-own. Whenevera subscriber uses al single short ring, that?l ,indicates that conversation is. l

completed.. When. a subscriberfs station is connected witharlme and, he desires to ring' 40 up the. centralstation, this may conveniently be d onewitn a single long ring.- rlhe disconnecting nell apprises the subscribers'that the line 1s going to be busy. When the conmeeting-bell of a subscriber gives one long ring it notities him that he'is wanted at the Y, phone. When the `central operator rings each connecting bell-With one short ring it l notifies all of the subscribers that a secret conversation has ended and that all of the 50 subscribers now have access to the line.

- The manner in which a secretconversation may be carried on is as followsz--Sup-A pose that the subscriber at'station number2 wishes to talk secretly and that the line is in ,normal condition. lThe calling,` subscriber at station number 2 actuates his generator 66. This energizes the line and throws the line drop 25 at the central station. The centraloperator is thus notified thatsome person on the line wishes to maire a call. The

central oprator thereupon closes her listen-y ing key 44 and requests the calling subscriber to st ate. his number. The calling subscriber giveshis own number, and states,

csi the number of the'subscrber. he desires to '123l striking the iron rivet 132.;

mamas i l call. The central operator then closes'the `ringing key, thus bringing the contact mein-y ber 28 into engagement with the Contact member 30, and also bringingthe contact member 29 into engagementwith the-contact 71) member 33. IThe centrai operator neatcloses vthe contacts 53 and 55. Generator 'fwire 62,-contact 53,`w1res 52 and 50, contactmembers 33 and 29, ntlluctor 27, contact 21A, line wire22, wind4 Ylgs to2, 103, line wire 21, '75 conductor 26B, contact 26A conductor 2G, contacts 28 anda-30,' wire 47, contact 55, wires 56 and 57, baci: to generator 58. Thist throws'the alternating current of the dynamo into the line wires 21 and 22 and ener 80 gizes the windings 102 and 103. VThe current vthus acting; upon these windings causes the armature 131i to be attracted against the cors 110. The small'bell 145 is thus enerl gized, and the crank cian-1.39 strikes the top of the stirrwp 131. This inturn raises'the iron rivet 132 from the magnet 112 and by so doing' breaks the magnetic circuit aiecting the rivet 132. This-rivet' beingra'ised with the stirrup 131, raises the contact spring` 128 9G out of .engagement with the contact spring 127 and'thus disconnects allof the subscrib-- ers stations. lll`he `centra-l' Aoperator next releases -thepush buttoncontrolling the two contacts 53 and 'and at practically the95 same instant turns the'switchv arm 14:8, as shown in Fig.. 15., to tli'e set of contents containing the'number of the calling station.

vThe switch-arniis pressed upon' the contacts .'repr'esenti g statioriythussending the 1C proper combination pulsating current'over the line, to energizethe .connecting bell at this particular-- station.'v v See Fig. 5. The current in question lnow energizes the wind ings 10i. and 1,05', but not thewinding 10G. Vl( The'armatu're 122 is thus vvcausedto be actuated.. Thisc'auses .the bell 1&3 to sound and also swinsstheconnecting inger 123 down against' thcadj accnti'nsul-ated iron riyet132r This rivet thereupon clings magnetically to '1 the magnet 112, and by Aso doing holds the A' 4Contact spring 128 against the contact miember 127, the station under considerationibe- -ing thus connected to the line. The centralV operator next places'the switch arm 1&8 l

over the contacts representing the number ot the station to be called. This l will suppose is atk station No.1. She next'presses the switch arm upon the contacts last mentioned. This throws a pulsating current into the 1 line., thus energizing the connecting bell at subscriberis station No. 1, by suppiying a -suitable selective ringing current thereto,

and moving the armature 122 against the core 107. This causes vthe bell to sound, and connects the Contact member 128 to the contact member 127 byxneans oitr f' ver the talking circuit. .The subscriber sta# tion No. 2can now talk secretiy to the malaria by means of the line drop last mentioned. f

As above explained, one short ring made by the generator ata subscribesvstation notifies the central operator that the vsecret conl versation is finished. Upon learning this the central operator actuatesher ringing key, closing contact members 29 and 33, and also 2S and BO. The central operator next presses the switch arm 148 while swinging the same and passing this arm over-the iirst 'five sets of contacts at the right. The effect 1 of this movement is to connect all of the subscribers to the line, the connections being made two at'a time by the alternating current,that is, one short ring, which ap- .prises each subscriber that the line is no 4longer busy and that each subscribers station is now `onnected to the line. The contact members 127, 128 are now closed and the line is in normal condition ready for use by any subscriber.

I do not limit myself to the precise construction shown, as variations may be'made ings mounted upon said core and disposedy concentrically, a polarized armature mounted adjacent said core and controllable thereby, a contact located adjacent said polarized armature and adapted to be closed by a movement thereof, an adjacent armature polarized and located in such position that when drawn toward the polarized core it disconnects said contact, mechanism controllable from the central station for electrically energizing the core and polarized armature asscciated therewith at different subscribers stations having different polarities in order to render them selective, mechanism controllable by a number of said electrically 'operated switches for connecting the subscribers set with the line and locking out other subscribers stations, and mechanism controllable by said electrically operated switches for disconnecting the subscribers set and then connecting the stations of other subscribers desiring to engage in secret conversation'.

2. In a party line telephone system provided with a central station and a plurality of subscribers stations, the combination of tions, the combinationvof a plurality a pluralityl of electrically operated switches lc-eatedat different subscribers stations respectively, each switch being provided with polarized cores and armatures, the polarity of which at one station is different from that at another station in order to render them selective, mechanism controllable by said 'electrically operated switches for connecting the subscribers set with the line and locking out cthersubscribers stations, and mechanism controllable by said electrically operated switches ;for disconnecting the subscribers set and thenrconnecting the stations of subscribers desiring to engage in secret conversation.

3. In a telephone system having a. central station and a plurality of subscribers staof electrically operated switcheslccated one at each station and provided with polarized magnets, the polarity of a magnet at one station differing from the polarity lof a corresponding magnet at another station in order to render said electrically operated switches selective, means controllable from the central station for energizing said switches in order to render them selective, mechanism controllable from the central station for locking out such sets as are not connected with the line, connecting mechanism controllable by said switches for bringing the sets into communication with the line when said sets are not locked out, and means controllable by the central station for restoring the line to normal condition.

4. An electrically operated switch for subscribers stations comprising a polarized core, a plurality of windings mounted thereon, and disposed concentrically, a polarized armature movable relatively to said core and controllable thereby, a contact located adjacent to said polarized armature and adapted to be closed by a movement thereof, and an adjacent armature polarized and located in such position that when it is actuated from normal position and drawn toward the polarized core, it disconnects said contacts.

5. An electrically operated switch com-l prising a contact, a stirrup mounted thereupon, an arm engaging said stirrup and adapted to move the same for the purpose ot' opening said contact, an armature connected with said arm Aand mountde to rock for the ur ose of actuating said arm a l v o polarized magnetic member located adgacent to said armature for the purpose of enarmature carrying said arm, said armature being polarized', a'po-arized ber disposed adja'ceritto said armature and having'a plurality 'of windings adapted,`

toy actu- 10' v'in normal condition,

armature operating independently of said mentioned last-mentioned armature mechanism and located adjacent said ger mounted to be actuated by saidsecondative 'relation to said contact for the'pur- I pose of connecting the same, a polarized rmagnetic armature disposed adjacent to said second-mentioned polarized armature and having a p lurahty 'of windings 'adapted to be connected infdiiierent ways and connect- ,in said contacts whenenergized with right Vpo arity ;to"actuate said second-mentioned polarized armature. if said second-men-- tioned non olarized armature connectedo posite sai lshaft and to said finger mount'- ved upon said vsecond-'mentioned polarized armature is notienerg'ized by windings about contact member, a .fin-

polarized armature and in oper-4 said non-polarized magnetic member disposed adjacent tol and against said non-polarized armature', when in normal position.

7. Apswtchfor party line telephone systems comprising a pair of contact members, lone of which Ais provided with a stirrup for 'moving it out of engagement ,with the other,

an arni extending through said stirrup, an armature carrying saidarm and mounted to rock in order to actuate said stirrup, a. magnetic memberl disposed adjacent to said armature, a second armature located adjacent to said contact members, a finger mounted 4upon said second mentioned armature and extending into engagement with one ci Asiaid'fg,contact members for the purpose of actuting and connecting same, and a magnetic member disposed adjacent the said last. mentioned armature for the purpose of energizing the latter, said magnetic member being polarized and provided with a plu-Y rality of independent windings.

Intestimony whereof I have signed my name4 to this specication inthe presence of i two subscribing witnesses.

HARLEY MELVIN WRXGHT. Witnesses:

W. A. Enorm,

ROBERT C. 'TERRELL Copies 'of this. patent maybe obtained for vc cents each. by addressing the Commissioner of Patents,

' Washington, Z0. C.

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