US1194367A - Automatic telephone-exchange system - Google Patents

Description

.8. G. DUNHAWI.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM,

APPucATmN FILED JUNE 7, 1915.

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BERT G.-DUNHA1VI, OF HAWTHORNE, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YQRK.

i AUTOMATJQC TELEPHONE-EXCHANGE SYSTEM.

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Application filed June 7, 1915.l Serial No. 32,688'.

To all whom t may concern:

Be it known that l, BERT G. D UrIHAM, a citizen of the United States,'res1d1ng at Hawthorne, in the county of Passaic andy This is es1' ecially'true in full automatic sysv tems, that is, in systems wherein the selectors and connector are set by a sender nianipulated by the calling subscriber, since some of the impulses would be lost -if transmitfwl before the finder had reached thecalling line terminal.

It is the object of this invention to provide a circuit arrangement for automatic finder switch s of the two-movement type, wherein this int `l'val 'is reduced to a minimum.

A feature of the invention istheprovisio'n of an efficient finder circuit arrangement of this type which obviates the necessity of a side switch or similar electro-mechanical control switch.I y

Referring to the drawing which illustrates only so much of a telephone exchange system as is necessary for a comprehension of the invention, the lines terminate as f calling lines. in multiple contacts 41, 42 of a number of automaticrlinder switches, a multiple test terminal 40 being alsoassociated with each line. The lines are d1- vvided in groups, the finder being adapted not shown), during the primary movement of such shaft in search of the calling line group.; Each groupy switch 5 1s also provided with a home contact 29, upon which the brush 25 normally rests. Each group of lines l1s also provided with a relay 17 which may be energized by any line relay 10 of the same group. T his relay, when energized, removes ground `from its multiple contacts 6 in the finder group switches, and simultaneously grounds starter wire 22 leading to the primary stepping 'magnet 1S of the pre-selected finder. The primary magnet 18 steps the brush shaft in a primary direction until the brush encounters the multiple group contact (3 of the calling line group, froml which ground was removed by the energization -of the corresponding group relay 17. The primary movement of the brush shaft is then stopped, at which moment the linder brushes 31, 32, 33 are in operative relation to multiples of the calling line group in the finder. The secondary movement of the brush shaft is then initiated, the test brush 33'in` this movement wiping over the test terminals a0 of the lines in the callingl group. When such test brush reaches the calling line test terminal 40 therein, it operates the cutofi relay 12'thereof which is connected to sald test terminal. The cut-off relay thereupon opens the circuit of the line relay 10 which in turn, by opening the circuit of the' group relay 17 and removing ground from starter wire 22, causes the finder brushes to stop in connection with the calling line.

A general outline of the system hav-ing been given, the ,operations involved in extending a calling line will now be traced in detail.

The removal of the receiver by the subscriber at substation A energizes the line relay 10 over the following circuit: free pole of battery, left winding of line relay 10, conductor 11, left armature and backl contact of cutoff relay 12, line conductor 14, the telephone set at substation A, line conductor 15, inner armature and back contactof cutoi'l relay 12, conductor 1G, right windingl of line relay 10, to ground. The energization of the line relay 10 closes the circuit of relay 17, common to this group of subscribers. This relay, upon its energization, closes the following circuit for the primary stepping magnet 18 to move the finder in a primary direction in search of the group of lines initiating .the call; free pole of the battery, pri-- mary magnet 18, its armature and back con* tact, conductors 19 and 20, primary off-nor# mal spring PON', starting conductor 22, armature and front contact of group relay 17 to ground. Relay 1s energized in multiple with the primary stepping magnet 18 by way of conductors 24, 20,V primary offnormal spring PON to ground, over the circuit just traced'. itself to ground over the following circuit:

.free pole of battery, `relay 23, its inner armature and front contact, conductor 28, Contact brush 25, home contact 29, conductors 30, 19,

I 20, primary off-normal spring PON, starting conductor 22, to ground at the armature and front contact of group relay 17. Thus, the primary magnet 18 steps the brush shaft in a primary direction as long as its circuit is closed at the inner armature and f-ront contact of relay 23, which circuit is in turn f maintained closed as long as the brush of the group switch S encounters contacts 6, grounded at the armatures and baclrcontacts of-the relays 17 of non-calling groups.

7h/en the contact 6 of the calling line group i is reached, which Yis assumed to be the first, and from which ground was removed by the energization of the group relay 17, the circuit of relay 23 is opened and the de'energi- -Zation of this relay opens the circuit-of the primary stepping magnet 13,- thus causing the primary movement of the brush shaft to be stopped with the brushes 31, 32 and 33 in operative relation to the group ofalines4 ,containing the calling line whose subtuton ductor 22, to ground at the armature and front contact of said group relay, and after the first primary step of the finder brush shaft and the consequent transfer of offnormalv spring PON to its lower contact, this relay locks itself over the following circuit: free pole of battery, relay 38, its upper armature and front contact 37, 'start-I ing conductor 22 including spring PON',

armature and front contact of group relay 1 7 to ground'. Thus the denergization of relay 23, as brush 25 reaches 'the ungrounded calling group contact 6, and consequent engagement of its outer armature and back contact, immedlately closes the following ...circuit for the secondary stepping magnet 34 to movethe finder brushes 31, 32, 33 over the `4yterminals of the selected group in search of the `calling line therein: free'pole of the battery, stepping magnet 34, its armature and back contact, conductor 35, outer armature and back contact of relay 23, conductor 36,`

upper armature and front Contact 37 of relayl 38, starter Wire 22 including spring This relay 23 then locks -relay 17'to ground; .L

low

PON, now closed to its bottom contact.y to ground at the armature and front contact of group relay 17. rPhe test brush 33 of thev line finder, in passing over the test terminals 40, energizes in succession the cut-olf relays 12 of the lines of the calling group. When the terminals 40, 4l., 42 of the calling line are reached, the energizalion of the cutoli' relay 12` thereof de'energizes the line relay 10, which, in allowing its armature to retract, opens the circuit of the group relay 17. 'lhe retraction of the armature of group relay 17 opens the circuit of the secondaryv stepping magnet 34, thus stopping the finder brushes 31, 32, 33, upon the terminals 41, 42, 40 of the calling line, thus extending the, calling line by way of conductors 43, 44 to the stepping relays 53 of a first selector. The (leenergization of the relay 17, upon the opera tion of the cutoii' relay 12, also denergizes relay 3S.

The energia-ation of relay 38, upon the attraction of the armature of group relay 17 when the call was initiated, closed a circuit for a relay 50 to open the connection of the battery to the brushes 32 during the ectting of the finder on t'ne calling line, to prevent interference with existing connections. This'circuit is as follows: free pole of battery, vrelay 50, conductor 51, 52, armature and front Contact 53 of relay 38, starter wire 22, including spring PON and its lower contact armature and frontvcontact of group ;Th'e denergization of relay 3.8, upon the :finding of the line, vcauses the release of this relay' 50, which at its `armature and back contacts associates the stepping relay 53 of the first selector with conductors 43, 44. This stepping relay is adaptedto be intermittently operated by the sender S at calling substation A. in the well-knq9wn manner, to set the first selector in operative relation to the desired group of trunks. The trunk hunting operation then follows. lSince this part of the system is not claimed herein, it is not shown in detail. that during conversation, relay. 50 is locked up in a circuit controlled by the lirstselec'- tor, and when this selector is released, upon the breaking down of the connection, a

ground is placed upon conductor 46 leading It is suiieient to statel back to the-finder. .The grounding of conductor 46 energizes the release magnet 45 to release the `finder over the following, circuit: magnet 45, finder off-normal contact PONE, conductor 49, lower armature and back con'- tact offrelay 38, conductor 46, to ground.

The release magnet 45 then closes the circuit of 'relay H50. When the finder reaches its normal position the release magnet 45 becomesdenergized by the opening of spring PONZ, and denergizes relay 50. Thus the connection to brushes 31, 32 is also opened during the restoration of the finder to prevent interference. lt will oe understood that while the calling line is shown as extended to a first selector, the invention is just as applicable to a-system'wherein the calling line ie extended to an operators position.

lll'lhat .is `claimed is: li v, v l. ln combination, groups of lines, lndere wherein said linee terminate in multiple contacte, a starting conductor adapted to preselect an idle Ender, a group switch aseociated with each inder and having a multiple contact for each grou and a brush adapted to cooperate therewith, a relay Jfor each group adapted normally to maintain ground upon. its group contact, a line relay tor cach line adapted to energize the correeponding group relay, and primary and secondary magnets for each iinder, of av circuit' for said primary magnet closed upon 'the energization of a group relay and leading through an ofi-normal Contact4 of said finder, a control relay therefor energized in parallel therewith, circuits for said relayi including a front contact thereof and grounded contacte of non-calling groups, a circ it for said secondary magnet controlled ata hack Contact of said control relay, and means Y for opening said circuit when the calling line `ie reached.

ln combination.,l groups of lines, linders wherein said lines terminate in multiple contacte, multiple test terminals for the lines in said ndere, a starting conductor adapted to presilect an idle finder, a group switch 'as,

sociated with each finder and having a. multiple contact for each grouprand a brush adapted to coperate therewith, a relay for eac-n group adapted normally to maintain ground upon ite group contact, a line relay for caen line adapted to energize the corresjionding group relay, and primary and eecondaiy magnete for each finder, of a circuit for said primary magnet closed upon the energization of a group relay and leading through.- an olf-normal contact of said linder, a control relay therefor energized in parallel therewith, circuits for said relay including a front Contact thereof and grounded/contacts of non-calling groups, a circuit for said secondary magnet controlled at a back contact oi' said control relay and a frontcontact of said group relay, and a cutoii' relay for each line connected to the test terminal of said line in the finder and i adapted to to be operated when the calling line is reached to denergize the line relay to cause the group relay to open the second- .ary stepping circuit.

3. The combination with an automatic switch, primary and secondary magnets therefor, a control relay, a circuit for energizing said primary magnet and said relay simultaneously, a circuit for continuing the operation of said magnet including an armature and front contact of saidrelay, and an operating circuit for saidsecondary magnet including an armature and 'back contact- Ieiner e. DUNHAM.

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