US959485A - Automatic telephone system. - Google Patents

Description

A. H. DYSON.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED JAN. 8, 1909.

Patented May 31, 1910.

5 SHEETS-SHEET 1.

I A. H. DYSON'. AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILED JAN. 8, 1909.

Patented May 31, 1910.

5 SHEETS-SHEET 2.

A. H. DYSON. AUTOMATIC TELEPHONE SYSTEM.

APPLIPATION FILED JAN. 8, 1909.

Patented May 31, 1910.

5 SHEETS-SHEET 3.

A. H. DYSON. AUTOMATIC TELEPHONE SYSTEM.

APPLIVOATION FILED JALLB, 1909.

959,485. Patented May "31, 1910.

5 SHEETS-SHEET 4,

aw I a Q mm o go I VaT 1 O n o 9 0M ,DL

A. H. DYSON.

AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILED JAN.8, 1909.

STATES PATENT @FFIQE.

ALFRED H. DYSON, OF CHICAGO, ILLINOIS, ASSIGNOR, 'BY lVIESINE ASSIGNMEE'TS, 'lO KELIJOGG SWITCHBOARD & SUPPLY COMPANY, A CORPORATION OF ILLINOIS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented May 31, left).

Application filed January 8, 1909. Serial No. 471,314.

To all whom it may concern:

Be it known that I, ALFRED H. DYsoN, residing in Chicago, Cook county, Illinois, have invented new and useful Improvements in Automatic Telephone Systems, of which the following is a specification.

My invention .has special reference to telephone systems wherein the lines are divided into groups and a number of line selectors are employed for each group to select calling lines as soon as they inltiate calls. In such systems, the line selectors are preferably not constantly operating mechanisms and a starting conductor is used common to the lines of a group and its selectors to start an idle lineselector when a call is initiated. v

An object of the present invention is to provide improved means for controlling the starting circuit. It will be seen that the starting means is a very important element in such systems, since it is common to a group oflines and all the lines must rely upon it. If such a starting conductor should for some reason he placed out of service, no calls from the line group which it serves could be successfully made until the trouble was ascertained and the starting circuit again put in service. By the present invention, a plurality of starting circuits are provided with mechanism such that, should one circuit be disabled, another will automatically, or without the aid of an attendant, be

connected into operative relation with the lines and the line selectors.

Another object of the invention is to provide means in an automatic telephone system, employing line selectors to" select call- 1 in lines, whereby it may be rendered feasib e, when at the conclusion of conversation --.the subscriber replaceshis receiver, to release all the selectors employed in the connection. In telephone systems Where automatic mechanism is employed to inter changeably associate first selectors with calling lines by the removals of'the receivers at calling substations, if one subscriber were to release all selectors by replacing his receiver, while the other subscriber, for example, forgot to replace his .receiver, the

result would be, were not special means provided to prevent it, that the line, whose receiver was left off the hook, would be automatically connected with a first selector and such first selector would accordingly be unavailable for further-use until the receiver was replaced at the connected line. By the present invention, means are provided to prevent the re-connection of a line, at whose substation the receiver is left removed, and consequently from beingconnected with a first selector when all the selectors employed in the connection are restored. In the present case, this is accomplished by locking the cut-oil relays of the lines over the line circuits, so that, as long as a line circuit remains closed after the cutoff relay has once operated, the normal battery connection to the line will remain open, thereby preventing the switching operations, necessary to con nect a calling line with a first selector, from taking place.

Another object of the inventionis to provide improved means forpreventing more than one line selector from causing its wipers to enter the group of'contacts containing contacts of a single calling line.

These and other features of the invention will be more specifically referred to in the following description of the drawings and will be specifically pointed out in the appended claims.

In the drawings, Figure 1, consisting of parts -1 to 4, illustrates in diagrammatic form an organization of automatic telephone circuits arranged to show one practical way 'of putting the present invention into service; Figs. 2, 3 and 4 are, respectively, left, front and side elevations of a selector mechanism adapted for employmentin connectionwith the circuits of Fig. 1; Fig. 5 is a top view showing adetail of the primary off-normal switch combination of said selector; and Fig. 6 shows a detail of the matic.

primary magnetand the associated-parts of the selector. Figs. 2 to 6 inclusive, as well .as Fig. 1, are, to a certain extent, diagram- Referring to be placed in consecutive order from left- 'to right, I- show at C andv C two substat'icns, each associated by line-limbs P, S

. as called lines.

with its individual line circuit D at the exchange; and at M and M I have shown duplicate master-switch circuits; at E, the circuits of a line selector; at F, those of a first selector; at H, those of a second selector; and at K, the circuits of a connector. Assuming a system of ten thousand subscribers, there would be ten thousand substations like C and G, each with its line.

The'subscribers, lines may be divided into groups of one hundred, both as calling and The. called multiple terminals 9, lO'and 11 will appear in the banks of a suitable number of connectors K and are there preferably arranged in ten sub- I groups often contact sets each, according-to the tens value of the lines; The individual calling multiple terminals, 51, 52, 53, of one hundred lines are grouped together in subgroups of ten contact sets each and are multipled to the banks of a suitablenumber of line selectors, say, ten, each such line selector, as E, having wipers 56, 57, 58, adapted for automatic adjustment; when a call is initiated to first selectthe sub-group includ-' 'ing the'calling line, and thereafter "the individual terminals of the calling line out of the sub-group. Each sub-group of ten lines has a pair of group contacts 54 and 55 which are multipled throughout the-line selectors of the'ten-line group.

Each line selector E is, according to the illustrated arrangement, permanently linked to a p'articular'first selector F, so that there will beas many first selectors as there are line selectors. Each first selector F has before its wipers 110, 111, 112, a hundred multipled contact sets 113, 11 1, 115 of second selectors H, which contact sets are arranged in ten groups of ten contact sets each, according to the thousands to which the second selectors are asslgned, all in the usual manner. A

- first selectorF hasits Wipers first directively adjusted to select a group of second selectors of the wa'ntedthousand, whereafter the first selector is automatically operated to pick out the contact set of an idle second selector of the group. Thesecond selectors H have before their wipers 110, 111*. 112,

one hundred multiple contact sets 116, 117,

118, of connectors assigned for connections to the different hundreds of the thousand which the, second selector serves. There may be ten connectors foreach hundred and themultiple contacts 116, 117, 118 of the connectors for each hundred will form a separate group before the wipers of a secfirst to Fig. 1, whose sheets are 0nd selector. A second selector is in the usual manner directly adjusted to select the group of connector contacts wanted, whereafter the wipers are automatically adjusted to select an idle contact set'out of the group.

"Before the wipers 141, 1 12', 143 of a connector K, are multiple contacts 9, 10, 11,of the one hundred lines which it serves, said contacts being grouped according to the tens value of the lines, as before indicated. The wlpers of the connector are first primarily adjusted responsive to directiveimpulsesto ing the set of a called line, and thereafter secondarily adjusted responsive to like impulses to select the individual contact set of'the called line, all in the usual way.

'Each subscribers line, as C, in addition to the calling and calledmultiple terminals before referred to, has its line relay LR for operation when a call is initiated to influence a master-switch M to start a line se-.

lector, E, to alter the electrical condition of select the sub-group of contact sets containthe individual calling multiple terminals 51, 52, 53, to render them selectable; .and also to alter the electrical condition of the group terminals 5 1 to render them selectable. In addition, an operated line relay grounds the multiple private called contacts 9 of the'line at the connectors to render them busy. The cut-oil" relay CO includes armature switches to dee'nergize the line relay and has an energizing Winding 12 energized in response to the selection of the line by a starting impulses are transmitted to the line selectors. Before the wiper 30, are contacts 31, each connected by a wire 43 to a-difl'erout line selector, the wires 43 being employed to render the contact set 28, 31 of a line selector busy at themaster-switch. Between the contacts 28, are placed the contacts 28 connected together and also connected by a W116'29 with the contacts 31 before the wiper 30, which contacts 31 are placed between the contacts 31. The wipers 27 and 30 are preferably always operated in the same direction of rotation, no restoring the usual armature-actuated pawl to" mechanism being necessary, and in practice the contacts 28, 28", may form a circle about the axis of rotation of wiper 37, while contacts' 31, 31 also form a circle-about the axis of rotation of the wiper 30. The mastor-switch relay 26, when energized, grounds the wiper 27 to start a line selector and said relay 26 is common to the one hundred lines of the calling line group, being so rendered by the common conductor 25 having one hundred branches, one to each line relay of such line group.

Referring to the group relay 23 controll g by its armature the selectable condition Jf the group contacts 54, each relay 23 of a sub-group of ten lines is common to the subgroup, being so rendered by a conductor 24 having ten branches, one to each line re-. lay of its sub-group.

The remaining circuit connections Will be best understood from the following description of operation, wherein itis assumed that the line C is to be connected for conversation with the line C, whose number may be assumed to be 2845, it being assumed that at the time substation C initiates the call, the

apparatus is in the normal condition-that illustrated in- Fig. 1. Subscriber C removes his receiver, whereupon hook-lever 1 engages its upper contacts and closes a circuit ofbattery-B over' the calling line, extending through normal contact 22, limb S, contact 4, the magnet impedance 2, the transmitter, returning through contact '3, limb P, normal contact 19, line relay LR, to ground. Armature 15 is then attracted to ground the called contacts 9 at the connectors, rendering them busy. Armature 17 disconnects ground from multipled private contacts 51 of the line selectors and energizes the group relay 23 whose armature removes ground from wire 49 and so from the group contacts 54 at the line selectors, rendering them selectable. By armature 16, relay LR is disconnected from the line and locks in series with the left winding of masterswitch relay 26, the circuit being traced through heat-coil h, normal contact 35 to battery. The attracted armature of relay 26 grounds the starting Wiper 27 of masterswitch -M, circuit being traced through the engaged contact 28, wire 44, normal contact 64, primary relay PR, to battery B Relay PR energizes and its armature completes a circuit for alternating current traversing the winding of magnet PM, whose resulting actuations drive wipers 56 to 60, inclusive, in a primary direction, each actuation bringing'the wipers 56, 57, 58 below a different group of contacts 51, 52,

58., and wipers 59, 60 to engage a successive set of contacts 54., 55. On the first primary step, the P0 contacts are shifted to their alternate positions, the shifting ofcontact. 64 opening the initial energizing circuit of relay PR, so that thereafter said relay depends for its continued energiz ation upon a circuit extending through attracted arma ture 66, through group wiper-59, and to grounds over successively engaged group.

contacts 54 of non-calling sub-groups. Relay PR will accordingly remain energized and magnet PM will receive successive actuations as wiper 59 is stepped along, until .said wiper engages the group contact 54 of the sub-group containing the calling line, at.

ternately energized and deenergized, step ping the wipers 56, 57, 58, in a secondary direction to engage successive contact sets 51, 52," 53 of lines of the selected sub-group, the wipers 59, 60 at this time remaining stationary. initial energizing circuit of relay I opened at contact 74, because of the-shifting from normal of the secondary oil-normal, SO, switch contacts on the first secondary etc of the line selector. thereafter depends for energizing current upon a circuit extending through its at- On the first secondary stegkthe 1s' Thus the relay?!v tracted armature 78, through contact 67, to

wiper 56 and to grounds at successively engaged individual private multiplecontacts 51of non-calling lines of the selected subgroup-- As soon as wiper 56 engages the contact 51 of the calling line, such contact will be ungrounded, because the line relay of such line is operated. Relay deenergizes and its retracted armature .79 opens the energizing circuit of secondary magnet SM so that said magnet remains inert, the wipers 56, 57, 58 accordingly resting engaging the contact set 51, 52, '53 of the calling line.

As soon as the relay SR first operated, its

armaturcs 76 and 81 bridged the wires 84 and 85 so that the relays PR and SR at F energized. When relay SR deenergized,.the' relay PR, because of the make-before-break arrangement at 76, had a substitute circuit completed from battery A over wire 84, contact 57 52,-normal contact at 20, winding 12, to battery B. Relay CO accordingly energizes and, by its armature 19, extends the circuit of relay PR over limb P,

' through contact 3, upper contacts at l, magnet 2, contact 4, limb S, wire 48, contact 53-.

58, and wire 85 through relaySP/ to battery These shiftin-gs in the circuit of relay B PR occur without its armatures retractin The attraction of arm'atureQO of relay C locks the relay to'ground through wire' 46,

contact 51'56, and contacts 67 and 78. The

opening of contact 21 deenergizes relay LR and the left winding of relay 26. On the retraction of armature 15, the grounded armature-2O is connected to multiple contacts .9 at the connectors continuing the calling line busy. The private contacts 51 of the calling line at the line selectors are rendered unselect-able, as soon as theline is selected, by the ground at armature 78, and so contlnue while the connection exlsts.

Returning now to the starting of the line selector E, the shifting of primary ofi-normal contact 63 on the first step closed a circuit from ground. at 68, through normal contactv75, resistance r (the commonwire 45 having tenbranches, oneto each line selector served by master-switch M) and through the right winding of relay 26 to battery through heat-coil h. .The windings of relay 26 are opposed and the resistances of relay LR and o r are so proportioned that the core of relay 26 is substantially neutral and its armature immediately retracts, ungrounding the starting-wiper 27. During the secondary travel of line selector Eunder the influence of relay SR, the neutralizing circuit through the right winding of relay 26 is continued closed at armature 77 of relay SR. When the line selector E has completed its selection, the opening of contact '7 7 to deenergize the right windlng of relay 26, and the opening of contact 21 to de energize the left winding thereof, will occur nearly simultaneously and the armature of said relay may remain unattracted, or it may momentarily attract.

on the first step of selector E, the closure .of contact 62 causes a flow of current over contacts, relay R will remain operated and a contact set 28, 31*, the relay the magnet MM will continue to drive the switch wipers. If the neutralizing of the core of relay 26 fails to occurrsoon' enough to unground the Wiper 27 before the masterswitch wipers make their first ste to engage will continue operated and the master-switch wipers will engage the nextcontact set 28,31; and if this contact set is that of an idle line selector, the master-switchwill come to rest, since relay R will become deenergized, its circuit being opened at contact 62 of the idle line selector, and the wipers of the mas-. ter-switch Mfwill rest engaging contacts of such line selector,'ready to start the same. Should it by chance happen that the opening 8 of contact .21 and that of contact 77 occur,

one long enough after the other to cause the {momentary attraction of the armature of the relay 26, and if the wipers have come to rest engaging 'a contact set 28, 31, the only effect will be to initiate'a stepping forward of the said wipers to engage the next pen that, should the armature of relay 26 momentarily attract, circuit will be closed through the relay R too short a time to permit of a step of the master-switch wipers. It will be understood that by adjusting the various relays involved, the openings of con tacts 77 and 21 can be caused tooccur so close together that the armature of relay 26will not attract when a line is selected. The present arrangement avoids the necessity of very close adjustment in this regard.

As soon as line'selector E initiated. sec ondary travel, the attraction of armature 80 of relay SR closed a circuit through contact 71, the resistance 1", contact 60-55, wire 50, through the right'windin'g of relay 23-t0 battery B. The windings of relay 23 being now opposed and the resistances 1* and 1" being so proportioned that said windings now substantially neutralize the core of the relay 23, its armature is retracted, so that on the secondary travel of the line selector,

the multiple group contacts 54 are unselectable; By this arrangement, should two line selectors .be started and reach their groupcontacts 54 of the same group, one immediately after the other, only one of them will move its wipers into that sub-group of line contacts, unless indeed there betwo calling lines in said, sub-group. In such case, the

inclusion of one resistance r in circuit with the right winding of relay 23 will not deenergize said relay, since the fact that two lines are calling, which have contact sets in: will have caused the inclusion of a call before a first calling line has been se-.

lected by a line selector, the initiation of the second callwill cause the re-operation of the master-switch relay 26 to cause it to start an- It will also, beob served that if a second calling line initiates I other line selector, since the operation of the second line relay will include its winding in a branch of the circuit of the left winding of relay 26 and greater current will flow in dial 7 so thabthe same is now operable by hand. To transmit the called number 2345, subscriber C 'first rotates dial 7 clockwise until two insulating teeth are below the spring 3, and then replaces it, whereupon the dial is spr1ng-restored in a reverse clockwise direction, the two teeth causing two 'momen tary breaks at contact 3, whereafter a tooth at the extreme left of dial -7 causes one momentary break at contact 4. A stud 8 is mounted on the dial so that when the dial is in other than normal position, the stud is moved free of the spring 5 and the springs 5, 6 are by their tension connected together and to ground. The springs 3, 4 are therefore both grounded as long as the dial is off normal; and while two openings are being produced at contact 3, each of which will deenergize momentarily relay PR, the relay SR will remain operated by current over limb S and through contacts 4, 6 to ground. Conversely, when contact 4 is opened as before described, it will denergize the relay SR, but the contact 3 will be closed and the relay PR will remain energizedby current over limb P and through contacts 3 and 5-0 to ground.

The two deenergizations of relay PR transmit two current impulses from ground through contacts 91, 88, 99, magnet PM to battery, and two primary steps of first selector F are caused, the wipers 110, 111 and 112 being adjusted adjacent to the second group of second selector contacts, terminals of second selectors assigned to the second thousand. On the subsequent deenergiza-' tion of relay SR5, a current impulse is trans mitted from ground through contact 89, normal contact 92, fcontact 100,'contact 102 of the primary off-normal switch which was closed on the first primary step, and through.

relay BR to battery, operating-said relay whose armature 107 connects its winding through normal contact 104 with the private wiper 110. Armature 108 closes a circuit for alternating current through secondary magnet SM and said magnet steps the wipers 110, 111, 112 step. by step to engage successive contact sets of the selected group.

Until that of an idle second selector is reached, the wiper 110 will engage successive'ly grounded contacts 113" and. the relay BR will remain energized. As soon, however, as the wiper 110 engages the contact 113 of an idle secondselector, such contact will be disconnected from ground and'relay BR will deenergize, theopening of contact 108 preventing further actuations of magnet SM so that the wipers of switch F will remain engaging the contacts of the selected second selector. The'clo'sin of normal contact 107 will have connecte' ground through wiper 110 to the contacts 113 thus selected, rendering them busy. The secondary offnormal contacts 99, 100 were shifted on the first secondary step of-the first selector F so that magnets PM and BR were discon-' to' 2399. The. following deenergization of relay SR transmits a current impulse from ground, through contact 89, normal contact 92, contacts 109, 112-115, 102 and relay BR and said relay initiates and controls secondary travel of second selector H to select contacts of an idle connector in thesame manner that relay BR controls the travel of first selector F, the detail of operation of second selector H bein apparent from that given for the first se ector, like parts at H and F being given like reference characters with different exponents.

leases it. Four resulting denergizations of relay PR transmit four current impulses through contacts 111-114,1l1 ,-117, 1.21 and magnet PM to battery, causingfour actuations of said magnet and four primary,

steps of the, wipers'141, 142, 143, to select the fourth group of called line contact sets 9, 10, 11, comprising contacts of lines 2341 to 2349 inclusive, followed by those of line 2340, zero being ten impulses. A following deenergization of relay SR will transmit a current impulse through contacts 112-115, 112 -118, normal contact 122, secondary magnet SM to battery, which magnet will cause one secondary step of the wipers 141,

142, 143, toward the edge of the contact bank, but said wipers do not, at the conclusion of this step, engage the first contact set of the 'group, since the normalposition of the wipers of a connector, after their rim-ary adjustment, is always two secondary steps distant from the first contact set of the selected" group. By this first step, however,

Sub-" scriberC now actuates his dial until four teeth are brought below spring 3, and re' tion shown, connected to the active side of the secondary off-normal contacts 121, 122

are shifted,121 to engage its alternate contact, while 122 is shifted sufficiently, to

disengage its normal contact, but not to en- 7 "gage its alternate contact, the latter occurring only on the second'se'condary step of the connector. The calling subscriber. C now actuates his dial until five teeth are brought below spring '3, and releases it.

Thereafter a deenergiz'ation of relay SR transmits a current impulse over the beforetraced path through contact 118, thencethroughalternate contact 122, normal contact 128 and lower windin of test relayTR'to battery B. Relay LOR, said relay, by'armature 127, locking to ground at 124. The test relay TR'n'ow proceeds to test the called line, and if said line be found idle, the ringing generator.

ill

will be connected to the called line to si thesubstation. If the line be busy, the ringing generator will remain excluded and the busy'interrupter I will be connected with the calling line, at whose substation the sub- 'scriber will hear thebusy signal and will rciplace his receiver to disconnect the central ce apparatus.

Assuming first the called line to" beidle, its multiple contacts 9 willbe in the condibatteryB through contact 15 of relay LE andwinding 12. The engaging wiper 141 is, .011 the attraction of armature 133' of relay TR, also connected to the activeside of the of armature 128 of relay LOR opens the cir- 'cuit of the lower windm of the relay TR,

said relay deener izes, since the two ends of its upper win ing are connected" to the active side of battery B and said relay TR denergizesL As soon as this occurs, a circuit is completed from ground through ring ing control relay RCR, contacts 126, 133, 141--9, 15, winding12 of relay CO of the called line to battery B and relays CO and RCR both operate, the ormer, by its armature 20, connecting the ground through relay RCR to the priyate contacts 51 of the called line at the line selectors, so rendering them busy. The interrupter I, a constantly rotating device, will now alternately energize and deenergize the generator relay GR, whose armature 140 alternately connects and disconnects the ringing generator with and from the called line, causing. its substation R operates and itsarmature 134 actuates the locking relay,

battery,B 'Thus as soon as the attraction bell to periodically sound in the well-known I manner. When the called subscriber removes h1s receiver, hook-lever 1 closes a conductive circuit through the substation; and f as soon as armature 140'is retracted, a cir-' cuit is completed as follows: from the'active side of battery A, through answering relay 7 AR, contact 129, normal contact'140, con tact 142-10, limb P, contact 3, the trans mitter and upper hook-switch cont-acts, im-

pedance 2, contact'4, limbs, contact 11 143, inductive resistance IR, attracted arma ture 130, t'o battery B. This flow of current energizes the transmitter at substation 'C for talking andoperates relay AR, whose armature 135 actuates closing} relay 'CR' which, by armature 137, locks to ground at contact 124. Armature 138 opens the circuit of relay GR so that it remains de'ner-- ized' .rin' in current, accordin l 'remain-- 7 111g exciu ed from the called line. Anna tures 136 and 139 complete the talking circuit at theconn actor and the two subscribers are now in conversation over a circuit traced from substation C and over, the heavily marked conductors to substation C, the

calling and called portions of the talking circuit being united inductively by the condensers at F. I a r It will be seen that when the called subscriber answers and contacts 136, 139are closed, positive battery at A is, over the 112", 115112, and alternate contact'92 and relay RRT with the negative battery B so thatthe relay RR .is held energized during conversation by current passing over the called line. On the operation of relay RR, its armature 97 energizes locking relay LOR" which, by armature 93, looks to ground at 101 andover wire 82, to ground As before stated, when either subscriber replaces his receiver, all the central ofiice switches are restored to normal. Assuming that subscriber C replaces his first, the opening of alternate contacts at 1 will deenergize, simultaneously for the first time, relaysPRf and SR and armatures 87 and 90 are simultaneously retracted to close the release cirk cuit 83. Current will then flow from ground through release relay RR? at F, -contacts 90,

relay RR at E, to battery B and both said relays energize. 'RelayRR- atE, by armature 69, actuates release magnet RM by current through contacts 61 and 65 and said magnet withdraws the lreta'i'ning pawls of line selector E and its wipers and. off-normal called subseriberfs' line, connected over a return circuit traced through contacts 11 8 .87, wire 83, contact 73, lower winding of contact's are automatically restored to norma l. Relay RR, by armature 69, has locked to R and until the wipers are fully restored, at which time the primary off-normal PO ound inparallel with release magnet ated. During restoration, the talking wipers 57, 58 are held on open circuit, since armature 7 O maintains relay SR operated until the wipers are free of the contact bank, as hereafter explained.

Relay BB at F, by armature 103, locks itself in series with relay BR, and magnet RM is energized by current from ground through contact 108, alternate contact 105, and the winding of said magnet to' battery, the magnet being then effective to withdraw the retaining paw-ls of first selector F, whose wipers will be automatically restored, at

which time the opening of primary off-normal contact 102 deenergizes relays BB and BB". Before magnet RM can attract its armature, however, a current impulse will pass from battery B through alternate contact 1'04, contact 110-*113, contact 101 release relay KB of second selector H, which relay, by armature 103*, looks in series with busy relay BB Current will then flow from ground through alternate contacts 108*, 105', release magnet RM to battery, and said magnet withdraws the retaining pawls of second selector H, causing its wipers to be restored to normal, at which time the opening of contact 101 will 'deenergize relays BB and BB Before magnet RM can attract its armature, however, an impulse of current flows from .fbattery B through alternate contact 104, contact 1 10*- 116, 119, release relay RR to ground, which relay, by armature 123,1ocks itself and, by

armature 124,. actuates release magnetRM which withdraws the retaining pawls of connector K, whose wipers 141, 142, 143

thereupon restore to normal, at which time the opening 'of contact 120 of course de-" energizes the release relay RR. It will be observed that zon the attraction of armature 124, the circuitsofyrelays LOB and CR are opened and said relays deenergi'ze. Al-

though thew-ipers 141, 142-, 143 have now been restored to normal and accordingly disconnected frointhe contacts 9, 10, 11, and

tive side of battery A, through winding 13,

alternate contact 18, limb P, to the raised hook-lever v1, returning over limb S, alter nate contact 22, and through winding 14 to the active side of battery B. v The line relay LR can accordingly not be energized. When the called subscriber C replaces his .receiver, the openingof a conductive circuit at the substation de'energizes windings 13, 14, the armaturesof relay CO retract, 'and should the subscriber now remove his reciver, his line relay LR will operate and cause his line to be selected by a line see-- lector.

lVere the called subscriber C to replace his receiver before the calling subscriber C, the opening of the conductive circuit at substation C will deenergize answering relay AR at K and relay'RR at F. On the deenergization of the latter relay, circuit is completed as follows: from ground throughrelease relay EH closed contact 94, normal contact 96, attracted armature. 95 and over wire 83 and cont-act 73, lower Winding of release relay RR to battery B The energization .of these relays causes the restoration to normal of all the central otfice apparatus in the way just described. If it be assumed that the subscriber C still has his receiver removed, his relay 00 will remain operated, although line selector E has been disconnected therefrom, because of the circuit through the locking windings 13 and 14, traced through alternate contacts 18 and 22.

Let it now be assumed that at the time the connector K made connection with the called line, said line was busy. In such case, the private contacts 9 would be grounded. in one of the several Ways heretofore mentioned;

and on its initial operation, the relay TR would be locked by current flowing from battery B through the upper winding of said relay, alternate contact 133, contact.

141'-9, and to ground. Busy interrupter I would remain connected to the upper talking conductor at connector K and the calling subscriber C would hear the busy signal in his receiver. He would accord i 1. re lace his receiver, deener izing relii y s Plt and SR and the central olfice apparatus would all be restored-to normal.

Returning now to the master-switches M and M, let it be assumed that the idle line selector, for which the relay 26 closed a starting circuit, failed to operate and start to select the calling line. In such case, the contact 63 would remain open and current flowing from ground a the alternate contact, the release of contact 37, linked to 35, being simultaneously shifted to engage its alternate contact. On the closure of alternate contact 35, the bell 36 will sound to advise the central ofiice attendant that the master-switch M is in trouble,

operatively associate the=circuits of master" switch M with the common conductor 25 extending to, the line relays, a-nd with the Suppose the line selector E starts and for,

some reason sticks at some point in its operation without completing its selection; it will be obvious that current will continue to flow through both windings of relay 26 and the heat-coil 72,, will blow and in this case also cause the connection in circuit of the I substitute master-switch and of the alarm bell. Furthermore, should therelay R get out of order or have its circuit closed with the result that its ari'nature stayed continuously attracted, thus causing magnet MM to continuously rotate the wipers 27 and 30, the generator impulses will, after a certain length of time, blow the heat-coil h,

at which time alternate contacts 32 and 34 will automatically close, the closing of 32 causing the bell 33 to sound, while the cloi sure of 34 energizes the relay 88 which operatively connects in circuit the substitute master-switch M. i It will of course be the duty of the attendant, as soon as either bell sounds, to ascertain the trouble as speedily as possible and replace the blown heat-coil with a new one, thus again cutting into circuit the regular-service master-switch M. The master-switchM has heat-coils h and h similar to the coils h and 71, of M, so that if, what would be a very rare occurrence,

both master-switches should be disabled, the fact would be at onceadvertised to the central oflice attendant. It will be observed that the wire connected to the wiper 30 of master-switch M is connected to alternate contacts 37 and 34 so that, if the heat-coil were to blow, the contact of the line selector engaged by wiper 30 will be rendered busy before the wiper 30*. Thus a disabled line selector, or a contact on which the disabled master-switch M rests, will be incapable of selection by the alternate master-switch when it is cut into circuit.

Referring to the mechanical drawings,

Figs. 2 to 6, the one hundredcontact sets 51,

52, 53, which comprise the main switch bank, are arranged in ten vertically extending groups of ten contact setseach, being mounted before the wipers 56, 57, '58,'as shown in Fig. 3,'as if extending through the inner surface of a section of a hollow sphere. Said wipers 56, 57, 58- are given their primary' adjustment, by being rotated step by step from left to right beneath the lower edge of the contact bank as viewed in Fig. 3, eachstep bringing them beneath a different group of contact sets. Their secondary adjustment is effected by moving the wiper ends. adjacent tothe bank upward, each secondary step causing them to engage a different contact set. As shown in Fig. 2, the

wipers are supported by a primary shaft PS and extend throughsaid shaft, being pivoted at 209. The rearward extending portion of the wiper mounting is provided. with a bearing engaging the slotted wheel members 210, free to rotate in the bearing. Engaging the slots, is an angular piece 208 fastened to secondary shaft SS and sufiiciently broad so that it remains .in engagement with the slots after any primary adjustment of the wipers.

,The group contacts 54:,- 55 are mounted be- .low the contact bank and their associated group wipers 59 and 60 are rigidly fastened .to the primary shaft PS and partake only of the primary movements of the switch.

For rotating the shaft PS and thus effecting the primary adjustments of'the wipers, a

primary ratchet 225 is rigidly attached to the shaft PS, as shown in Fig. 6. The'driving pawl 202, adapted for actuation by the armature of primary magnet PM, is arranged on successive actuations to engage successive teeth of the ratchet 225' and so drive the ratchet, the primary shaft, and

the wipers 56 to 60, inclusive, rotarily step by step. The primary adjustment of the switch is effected against the tension of the spring 213 shown in Fig. 4; and to prevent back movement, the primary retaining pawl 203 is provided. After the primaryad ustment is completed, actuations of secondary magnet SM will effect successive thrusts of its armature controlled pawl 206, which, en gaging successive teeth of an associated ratchet cut in secondary shaft SS, drives said shaft downward step by step, the sec-' ondary retaining pawl 205 holding the shaft SS against back movement after each step, which would otherwise occur under the in fluence of the spring 214 linked to the secondary shaft SS by the lever 215,, whose long arm loosely engages a screw inserted in the shaft SS. Each downward step of shaft SS moves the piece 208 a step downward and the contact ends of the wipers 56, 57,

58 are moved upward to engage successive contact sets of the selected group.

In Fig.5, the piece 200 is shown fastened to the shaft PS and carrying a stud 201, which normally engages an angular extension of the primary off-normal spring 64, to

which the other s rin s 61, 62, 63 are linked by insulating stu s. n the first-rotary step of shaft PS, the stud 201 frees the spring 64 and the primary off -normal springs are moved by their tension to their alternate positions. As shown in Fig. 4, an angular piece 211,.normally holds in its raised position an insulating s acer connected to the secondary ofi-norma springs 73, 74, 75. A

piece 212, fastened to secondary shaft SS, normally holds the arm 211, which extends parallel with shaft SS, in its raised position. ()n the firstdownward step of shaft SS, the piecev 212 clears the piece 211, which then drops down, allowing the springs 73, 74. 75 to be moved by their tension to their alternate positions. with a tooth 226, adapted when the piece 211 drops down, as described, to engage any adjacent tooth of the primary ratchet 225 to render ineffective the tension of thespring 213 while the secondary shaft SS is being restored to normal, as hereafter described.

" To restore the described mechanism to normal, it is only necessary to energize the release magnet RM, whose armature 204 then engages a rearwardly extending por-' tion of the primary retaining pawl 203 and engagement with the tooth of the primarv rotates said pawl'to free the primary ratchet 225. The pawl 208 has a projection 207 interlocking with the secondary retaining pawl 205, so that the described movement of the primary retaining pawl 203 serves to also withdraw the secondary retaining pawl. Thereupon the spring 214; is effective to raise the shaft SS upward until the piece2l2 raises the piece 211, whereby the secondary off-normal contacts are restored, and abuts upon the lower surfaceof the switch frame. Until this occurs, the tooth 226 remains in ratchet 225. WVhen the secondary shaft reaches normal, however, at which time the wipers are below the lower edge of the contact bank,the tooth 226 disengage-s ratchet 225 and the spring 213 is effective to rotate theprimary shaft and the wipers of the switchsback to normal, atwhich time the stud 201 (Fig. 5) restores the primary off- .normal contacts.

The switch. justdescribed, which is specif ically arranged to perform the functions of line selector E, may also serve for first 'selector F, second selector H, and connector K. For these latter uses, however, the group contacts and group wipers are not. required; and in thecase of the connector, the wipers will be so adj ustcd with respect to the lower edge of the contact bank as to be two steps distant from the first contact set of the selected group after the primary adjustment is completed, as already referred to in connection with the circuits.

The various battery symbols, shown as havingthc same pole grounded, may be asingle source of current if preferred, and

the variousgenerator symbols, shown in systems other than those of-the specific char actor herein described, and the appended The piece211 is provided claims are intended to be of scope sufficient 1 responsive to current over-any of said lines,

of a second like circuit and a'switch auto- .matically operated responsive to trouble in said organization to substitute said second circuit for said first-mentioned circuit in said organization. I

2. In a telephone system, the combination with an organization comprising telephone lines, selectors, a starting circuit operable responsive to current over said lines and mechanism sensitive to the electrical condition of said circuit to connect said selectors interchangeably with said lines, of a second starting circuit, and a switch automatically operated responsive to trouble in said organization to substitute said second circuit for said first-mentioned circuit in. said organization. I 3. In a telephone system, the combination with selectors and means for starting the paratus responsive to an abnormal condition of said means for automatically connecting said second conductor into operative relation with said selectors.

5. In "a telephone system, the combination with selectors, of a conductor for distributively starting the same and operatively associated therewith, a second conductor for distributively starting said selectors and inoperatively associated therewith, means for altering the electrical condition of said first conductor in order to start a connected selector,. and an automatic switch operated responsive to failure of said connected so lector to start to operatively dissociate said first-conductor from said selectors and operatively associate said second conductor therewith. a

,6. In a telephone system, the combination with selectors, of a conductori for distribut-iv ely starting .the sameand operatively associated therewith, a second conductor for distributively starting said selectors and inoperatively associated therewith, means for altering the electrical condition of said first conductorin order to start a connected selector, .and means responsive'to a failure ofsaid connected selector to properly perform its functions serving to operatively dissociate said first conductor from said selectors and operatively associate said second c'onductor therewith. v

7. A telephone organization including telephone lines, line selectors to select said lines,'a master-switch common to said selectors and lines operable responsive'to current over a line to start an idle selector, a second master-switch, and automatic means responsive to trouble in said organlzation to substitute saidsecond master-switch for said firstswitch.

8. A telephone organization including telephone lines, line selectors'to select said lines, a master-switch common to said selectors and lines operable responsive to current over a line to start anidle selector, a second master-switch, a relay associated with the first master-switch adapted to initiate travel of a line selector, and means responsive to an abnormally prolonged How of current through said relay to operatively connect said second master-switch in circuit.

9. A telephone organization including telephone lines, line selectors 'to select said lines, a master-switchcommon to said select- .ors and lines operable responsive to current over a. line to start an idle selector, a second master-switch, a mag-net for adjusting said first master-switch, and means automatically operated responsive to abnormally I prolonged actuation of said magnet 'to operatively connect said second master-switch in circuit. 1 v

10. Ina telephone system, the combination with an organization comprising telephone lines and a circuit adapted to be in-- fluenced responsive to current over a line, of a second like circuit, a heat-controlledcontact, and means responsive to a prolonged flow ofcui'rent to change the connection of said contact to substitute said second circuit for said first-mentioned circuit in said organization.

11. A telephone system including telephone lines, selectors, a starting circuit operable responsive to'current over a line to initiate travel of a selector to selectsaid line, a second starting circuit and a heatcontrolled contact automatically operatedresponsive to the presenceof trouble to operatively connect into circuit said second circuit.

12. In a telephone sfystem, the combination with SBlBCtOI'SyRO a starting circuit operatively associated with saidselectors, a 1 second starting c1rcuit,and;a heat-controlled contact actuated responsive to disabling of the first starting circuit to automatically connect into operative relation with-said selectors said second starting circuit.

13. I m a telephonesystem, the 'combina-' tion with selectors, of a'comluctor for start- 'du'ctor with said selectors.

ing the same, means for interchangeably associating said conductor with different selectors, a second starting-conductor not in prolonged current How, and a switch automatically operated by the changing of the connections of said contact to connect said second conductor to operative relation with said selectors.

14. A telephone system including selectors, means for distributively starting said selectors, a second means for starting said selectors normally in inoperative relation therewith, apparatus for causing a current flow in said first means for the purpose of starting a connected selector, said current flow continuing upon failure of said connected selector to start, a heat-controlled contact adapted to be actuated responsive to an abnormally prolonged continuation of said current flow, said contact serving when actuated to operatively associate said second means with said selectors.

15. A telephone system including selectors, a conductor for distributively starting the same and operatively associated therewith, a second conductor for distr'ibutively. starting said selectors and lnoperatively associated therewith, means for. causing a current flow over said first conductor for the purposeof starting a connected selector, a-

heatcontrolled contact, means for actuating said contact responsive to an abnormal continuation of said current flow due to a failure of said connected selector to properly p erform its functions, and switch connections controlled by the actuation of said contact serving to operatively dissociate said first conductor from said selectors and operatively associate said'second conductor therewith.

16. Atelephone'system including selectors,

trolled contact, means for actuating saidcontact responsive to an abnormal continuation of said current'fiow due to a failure of said connected selector to properly perform its functions, an electromagnet adapted to ha ve its electrical condition changed respons ve to the actuation of said contact, ,and contacts controlled by said magnet shifted 5 p responsive to a change in its electrical condi. tion to operatively associate said second con- 17.- In atelephone system, the combination with terminal contacts. arranged in groups, a selector for selecting a group and then a contact of the group, a common or group contact for each said group, means for altering the electrical condition of a groupcontact to cause selection of its group by a selector, and means responsive to initial travel of the selector to select a contact ot the selected group to render the group contact unselectable.

18. la a telephone systein,the combination with terminal cont-acts arranged in groups, a selector for selecting a group and then a contact of the group, a common or group contact for each said group, meansi or altering the electrical condition of a group contact to cause selection of its group by a selector, and apparatus actuated by the selector on initiation of its travel over contacts of the selected group to render the group contact again unselectable.

it). In a telephone systenntlic combination with terminal contacts arranged in groups, a selector for selecting av group and then a contact. of the group, contact for each said group, means for altering=the electrical character of an individual contact, means for altering thc electrical character of the respective group contact, and means controlled by an operated selector for first restoring the electri -al character of the group contact and then the electrical character of the individual contact.

20. In a telephone system, the combination with terminal contacts arranged in groups,

a selector for selecting a group and then a,

contact of the group, a common or group contact for each said group, means for alter-.

ing the electrical character of an individual contact, means for altering the electrical character of the respective group contact,

means controlled by an operated selector for first restoring the electrical character of the group contact and then the electrical character of the individualcontact, and means rendering the selector ineffective to restore the electrical condition of'the group contactwhen more than one individual contact of the same, group have their electrical characters altered.

21. In a telephone system, the combination with normally unselectable individual terminal contacts arranged in groups, select ing mechanisms forselecting a group and then a contact of the group, a common or group contact for each said group, said group contacts being also normally "unselectable means for each individual contact e c for rendering it selectable, said means also bein ada )ted to render the res )ective group contact selectable, and apparatus operated b a selectin mechanism for rendering the group contact unselectable- .and

thereafter the associated individual. cont-act.

22. In a telephone system, the combination with normally unselectahleindividual terminal contacts arranged in groups. se

a common or group lecting mechanisms for-selecting a groupand then a contact ofthe group, a common f or group contactfor each said group, said. roup contacts being also normally unseiec'iable, m ans for each iiulividual contact tor rendering it selectable, said n'ieans also being adapted to render the respective group contact selectable, apparatus operated by a selecting mechanism for rendering the group contact unselectable and thereafter the associated individual contact, and appa ratus etl'ective by the operation'o't the means of a second individual contact of the same group to render inetfective the operation of said first-mentioned apparatus.

23. A. telephone system inclui'ling a tele;

phone line, selective mechanism to select said line, a starting circuit responsive to current over the line to initiate travel of said mechanism to select said line, means independent of said lines circuit for ,disconnecting said mechai'iism from said line, and apparatus including a relay held energized by current over said line to prevent reoperation of the starting circuit on disconnection.

A telephone system including a telephone line having multiple terminals, se-

lective mechanism to selectsaid terminals, means tor altering the normal electrical. condition of said contacts to render them solectable by said mechanism, means ctlective by connection of said mechanism with said terminals to render them uuselectable, apparatus independent of said telephone line to disconnect said mechanism from said terminals, and means controlled by current flowing over said telephone line serving to continue said contacts unselectable after disconnection of said mechanism.

27. A telephone system including a telephone line, an electromagnet individual to said line, link-circuits, automatic mechanism for interchangeably connecting said line with an idle link-circuit, and means controlled by said mechanism in its operation to include awinding of said magnet and said telephone line in circuit.

26. A telephone system including a telephone line, link-circuits, means normally adapted for operation responsive to currents over said line to automatically cause connection of an idle link-circuit to said line, a cut-off relay coi'iperating with said means, a circuit for operating said cut-otl' relay on connection of a link-circuit with said line, and a contact controlled by said cut-oft relay when energized to connect. its winding with said line to hold said relayenergized by current over said line after said link-circuit is disconnected theri-zfroin.

v27. A telephone system including tele phone lines, line selectors for selecting said lines, a line relay normally.conti'olla'bleresponsive to current over a telephone line to initiate travel of a line selector to select the said line relay disconnected while ourrent .line, a cut-01f relay serving to deenergize flows in saidtelephone line. 10

said line relay on selection of said line, In witness whereof, I hereunto subscribe means for initially energizing said cut-ofi' my name this 6th day of January, 1909. relay over a local 'circuit and thereupon ALFRED H. DYSON.

locking said relay over said telephone line Witnessesz whereby, aftGPClISCOIIIIBCtIOD of said selector THO AS H. FEReUsoN,

from said line, said cut-ofl' relay maintains CAROLYN WEBER.

Images