US1221168A - Telephone-exchange system. - Google Patents

Description

C. L. GOODRUM. TELEPHONE EXCHANGE SYSTE VI. APPLICATION FILED SEPT. n, 1914.

Patented Apr. 3.1917.

In van; for".- 04 wr/es L. oodrarn.

UNITED STATES PATENT-Q OFFICE.

CHARLES L. GOODRUM, OF BZlEtOQKlTYN, NEW YORK, ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPIZ'BATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Apr. 3, 1917.

Application tiled September 11, 1916. Serial No. 119,510.

ts object is to provide a circuit arrangement for systems of this character wherein a selector, failing to llnd an idle trunk, will be automatically restored to the beginning of the selected trunk group and again driven actisuch trunk group, this operation continuing until an idle trunk is found.

To accomplish this result the selector, in

the present embodiment of the invention, is provided with a release. magnet in addition to the regular release magnet which will draws both holding pawls. This additional release magnet will withdraw the secondar pawl only, whereupon the brush shaft is restored in So for as its secondary movement isconcerned, being retained in its set primary position in operative relation to the selected trunk group by the primary holding pawl. The secondary motor magnet then is operated to drive the selector hrushes ovelj such trunk group again.

The invention will be more readily understood when described with reference to the no inpanyin drawing, which shows only so much of a telephone exchange system as is necessary to a comprehension of the inventiont" l The invent-ion will be best understood frorn ax detailed description of the operation. U on the removal of the receiver at suhstallion A, a. line-tinder l the brushes 7;, b", and torminalls t, t, only of which are. shown, is set in motion to lind the calling,' line. \Vlieii the calling, line has been extended to a first selector FS, the stepping relay 1 thereof is energized over the following circuit: free pole of battery, right winding of relay 'l, arm 2 of the first selector side switch and its first Contact, conductor 3, brush ,0,

multiple t, line conductor 4, through the tele at substation A, line conbrush 1), conductor. 6, lirst contact, lei't phonic apparatus duetdi 5, multiple t, snle+switch arm 7 am] its winding of relay, 1, to ground. Relay 1 in 'teshterminals are grounded.

attracting its armature, energizes a slow relay 8, which in a ttraeting its armature inter poses a break in the circuits of release magnet RM and pr3pnres a circuit for a slow relay 9, which controls the escapement magnet 10 and also connects the primarv magnet PM to the hack contact oft-he stepping relay l.

'lhe calling p: rty now operates his sender h to transmit the lust digit of the wanted numla'r. The sender S is of the well-known type, which in returning to normal interrupts the line ri and a number of times corresponding to the digit in question Upon each retra tion of lhe'arniature of relay 1 an impulse is tr; nsuiiticd over the following path to primary magnet P: ground, arma ture and lJlltli contact of relay l. armature and l'ront contact of rcla S, which being slow holds its a1 mature attracted though its circuit is interrupted, 'comluctors 133' and ll. secondary Ulldltlllltll conta t- HUX, magnet PM. 'l'rce pole of battery. The slow relay is'cncrgizcd in parnllcl with magnet lhliand remains energizrd during the transmission of the impulses. l'hi '-".-..rela in attracting! its armature energizes escape magnet 10 The armature ol' matrnet l.\l is prorided with a stepping pawl 37, which engages a rotary ratchet 3 5 on the hrush shalt J1, and. rotates the shaft to position a set of brushes 11 in operative relation to the desired trunk group.

When the sen ler S restores and mainlains the line circuit closed, slow relay t alter a slight'interral ,liwomcs dei nergimal, open ing the cirruit of escape magnet 10, uhich thereupon pass:s the side switch to posi tion Ll. i i

In position :2 "he following circuit is closed for the secondary magnet SM todrive the positioned set olbrushes orer the selected trunli group: lrcc pole of hatter), contact if) ol release magnet R'M', magnet HM and its armature an I hack contact, conductor lo, side switch arnrlT and its second contact, to ground at the armature and front contact ot relay 1. 'lhe'armature ot' magnet SM is provided with a stepping pawl :54, which engages a vertical rat het 2! to elevate the shaft ll. ln liosition lot: the side switch, arm 18 connectn the escape magnet 10 in oil'- cuit. with the tgst hrushof thc set ol p tinned:brushes. idle trunks are those whr 'lhc escape reached. Therefore, when the first idle magnet is constructed to release the side switch from position 2 to position 3 upon its energization, when the hrst idle trunk is stepping relay'l fromthe connecting circuit conductors 3 and. 6, and extend 'the'calling line throu h to the talking brushes of the selector; %n this osition, side-switch arm connects the re ease magnet to the third or release wire to prepare the release .circuit which 1 is closed uponthe disestablishment of the connection. The vertical ratchet22 is'normally engaged by a hold ng pawl '24 and the rotary ratchet by a holding pawl-25. The awl 24 is integral with the armature 26 o the release magnet RM-, whicharrnature'is pivotedon a *pin27. Thepawl is integral with the armature 2813f the release magnet RM, which armature is also pivoted upon pin 27.

Upon the replacement of the receivers, a ground isplaced upon test wire 19'leading from the, connector, and closes the circuit of release magnet RM,.this circuit'including a primary off-normal contact PON closed upon the first rotary step of the shaft 21. This magnet in attracting its armature 28, withdraws the rotary pawl 25, and the arm 29 of such armature acts through'arm 30 on the armature 26 to withdraw the vertical pawl 24. The release magnetwhen energized, locks itself over contact 31 and remains locked up until the brush shaft 21 restores and opens oif-normal'con'tact PON.

.the brushes over theentire group, and "after "If, however, during the hunting 'opera tion oftherselector its movement s not stopped, the secondary magnet SM drives the "brushes have cleared the last set of trunk terminals, an insulated projection 32 on the brush-shaft 21 closes a contact 33 andenergiz es release magnet RM. 'This I magnet in 'attractingits armature 26, withdraws the vertical pawl 24: from the vertical ratchet 22 but does not disturb the rotary pawl 25, The-armature 26 in its attractive movement opens contact 15 and, closes contact'33"v .The opening of the former contact prevents further operation oithesecondary Y magnet-SM, and,theclosing of-the latter 66 contactnlaintainsithe magnet R'M locked I N; yclos'es upon the first upward step of the ,over a circuit includinga contact 35, which brush shaft 21. .The withdrawal of pawl 24 causes the, shaft 21 to .dropnand when it :reachesits lowermost position, the projec tlon 32z openscmitact. 35, unlocking magnet The release circuit for the selector in this caseis as followszfree pole of battery, re.- lease magnet RM, contact PON, arm 20 and its second contact, armatures and back contacts of relays 8 and 1 to ground.

\Vhat is claimed is:

1. In a telephone exchange system, in I combination with telephone lines, a selector, means for associating calling lines with said selector, trunk groups terminating in said selector, primary and-secondary driving magnets for said selector, means for operating said primary magnet to set said.

selector in operative relation to' a trunk.

group, automatic means for thereupon-operating said secondary magnet to drive the selector o er said group, means for stopping the *selectoronthe first idle trnnky-and means operated if 'no idle trunk is present for restoring said selector in operative relation'to said trunk group andjfor "again driving the same thereover.

2. In a telephone exchange system, in combination with telephone lines, a selector, a brush shaft therefor, means for associating a calling line with said selector, primary and secondary stepping magnets for said selector, primary and secondary ho1d-' in-g pawls for said brush shaft,arelease magnet adapted to withdraw both pawls,

an auxiliary release magnet adapted to withdraw only the secondary pawl, trunk groups terminating in said selector, a. sender for operating said primary magnet .to set said selector in operative relation to a. trunk. group, automatic means forthereupon opera ating saidsecondarv magnet to drive the Q selector thereover, means operatijye on the dises'tablishm'ent of the connection ito operate said release magnet to restore the brush shaft, means operated if the selector -fails to iary' Ina' .etto withdraw the secondary 'findf'an idle trunklfor'operating 'said auxil- I pawl, an means for thereupon again open-7f, ating the secondary magnet to drive the selector over the selected trunk group.

3. In a telephone exchange system, the

combination with telephone lines, a 'selec tor, trunk groups terminating therein, ,pri-

.mary and secondary stepping magnets for said selector, a driving circuit-for said sec} ondary magnet, primary and secondary holding paw-ls for said selector, a release magnet adapted to withdraw bothv pawls and an auxiliaryrelease magnetadapted to w thdraw only thesecondary pawl, a sender for operating said pr mary magnet to 18 the selector in operative relation to a' annies trunk group, means for thereupon closing"- said driving circuit to step the selector moreover, a testinq magnet adapted to be operated upon the finding of the idle trunk to open the circuit of said secondary magnet,- means actuated when the selector m reaches the end of the trunk group'for oper- 4 ating the auxiliary release magnet, a 105:]:-

3g circuit. therefor, said magnet being apted to withdraw the seoondaryflpawl, to

' open the circuit of the eeoondary'magnet and to close said locking ch unit, and means for reclosin opening sa1 said driving circuit and in:

looking CiICllllL when the selector is restored to operative relation to the 1 said trunk group to drive t'. 1e brushes again overisaid groun. I

' In witness whereof, I hereunto subscribe llngqename this 8th day of September A. D-.,'

CHARLES L GOODRUM.

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