US1174281A - Telegraph system. - Google Patents

Description

' To all whom it may concern:

mnrni) srai ns PA ENT .oFFI-O PAUL M. RAINEY, 01E GLEN RIDGE, NEW JERSEY, ASSIGNOR, .BY ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OE NEW YORK TELEGRAPH SYSTEM.

Be it known that I, PAUL M. RAINEY, a

.cit-izenof ,the United States, residing at in the county of Essex and Glen Ridge, State of. New Jersey, have invented certain new and useful Improvements in Telegraph Systems, of which the following is a. full,

clear, concise, and exact description.

This invention relates to telegraph systems of the type wherein a. plurality of lines terminate at, a central oflice, and its principal objects are to provide an automatic distribution of incoming calls to idle oper atom, and to prevent operators from interfering with abusy line. Y

I For the accomplishment of these ob ects the invention contemplates an automatic operator selector associated with each line,

together with means for notifying operators that a given line is busy. An overflow signalis likewise provided whereby notification is given that all the operators on a selector have been found in a busy condition.

The above and other objects of the invention will be fully set forth in the following description and claims, and will be more readily understood by reference to the accompanying drawing in which the system is shown diagrammatically.

The telegraph line L, extending from a central otfice C, may accommodate one or more branch stations 5, each equipped with the" usual key 6, sounder 7 and condenser 8. In busy districts there may be a large number of such lines terminating at the central ofiice. Each line is associated at the central ofiice with selecting mechanism whereby,

' when one of the keys 6 of any station on a.

line is depressed, such line is automatically connected to the first idle operators position at the central office.

The selectingmechanism comprises among other apparatus to be presently described, a selector switch 10. This selector switch has an arm 11 carrying. a pair ofwipers 12 and 13. These wipers are insulated from each other and the arm 11 and are adapted to be carried thereby over a plurality of contacts 14 arranged inpairs. Each pair of contacts ll is connected to an operato|"s posit-ion set 20, 21, etc, the number ot such Specification of Letters Patent.

Application filed December 7, 1914.

' Patented Mai. 7; 1916. Serial No. 875,842.

positions being determined by traflic condiset comprises switches22, keys arm 11 moves in the direction of the arrow, the wipers 12 and 18 will be successively connected to different operators position. Each oper ators positionset maybe, and preferably is, connected through in multiple as shown, to a number of selector switches 10, so that each operator may ans er calls originating over a number of telegraph lines.

There are many well known ways of causing the rotary movement of arm 11, but the mechanism preferred consists of a ratchet wheel and a pair of ratchets (not shown) controlled b'y "an electro -magnetic device composed of a stepping magnet "30 and a holding magnet 31. These magnets are intermittently energized when the proper circuit connections are established by interruptions of current caused by'a constantly acting interrupter 32. The stepping magnet 30' follows 1 .all of these current changes and, upon each energization, causes its ratchet to advance the arm 11 one step in the direction of the arrow. The holding magnet 31 is more sluggish in its releasing action, and. when once energized, will not release its ratchet during the intervals of no current produced by interrupter 32. In this way the arm 11 is not allowed to be retracted by its spring (not shown) during short no current intervals, but is released and allowed to return to normal on a longer no current interval. This type of selector switch is well known, one specific form being disclosed in a patent toJ. L. McQuarrie, No. 826.350, issued July 17, 1906.

The initiation of the action of selector switch 10 is controlled by a starter relay 35. Starter relay 3:) is provided with two armatures 36 and 37, both joined to a grounded battery 38.. LineL normally passes byway of a movable contact 40 of a quick acting line extending and interrlmter cut-off relay 41, through the winding of starter relay 35 to battery 38. W hen, therefore, the key 6 ofany branclrstation on line L is closed, a circuit is completed for starter relay 35,

similar to lot and 37. Armature 36, upon being attracted, grounds battery 38, through magnets and '31, a movable contact 42 of relay 41 and interrupter thereby starting the step-bystep rotation of arm 11-.

In order to arrest arm position for a connection to-an-idle operator,

'means areprovided whereby the flow of in-' terrupted current through maghet 30 and 131; is .stoppedwhen the moving wipers 12 'and" 1.3 engagle the pair of contacts 14 associated-with e first idle operators position. A lead from wiper 12 is connected to armature 45 of relay 41, while wiper' 13 is grounded through the left" hand winding 46 of a .slowacting relay 47, left-hand winding 48 of relay 41, and right-hand" windings 49 and 50yof relays 47 and 41, resepctively'. For purpose, to be hereinafter described, the sum of'the resistances of windings 46 and. 48 is made less than the sum of the resi stances'of windings 49 and 50.- Slow actingrelay 47 is provided with 25 tglo. armatures and 56. Armature 55 is c 'nnected to battery 38 and armature "56' is grounded and adapted to play between a back contact 57 and a front contact 58. Back contact 57 is joined to a contact spring .60 and an armature 61 of relay 41, while front contact 58 is connected-to relays 41 and 47 between their right and left-hand windings. Contact 60 is normally held away from engagement, with 'a companion contact spring 62 by an insulating lug on arm. 11, but makes engagement therewith upon the first stepof the selector switch. In

order to break the circuit, including interrupter 32, and providea-steady ground for 40 i magnets 30 and. 31 during the time of a connection,.re lay 41 is provided with a grounded "armature 63, which when actuated, separates contact 42 fromthe lead to interrupter 32'.

Any or 'all of the operators provided 1 with sets 20, 21, etc., or otheroperat'ors,

- which may be known as sending operators because their positions are not connected to selecto; switches, may be providedwith connecting sets 70, 71, etc. .Each of these sets consists of a connecting plug 75, key 76, sounder 7,8, resistance 79, condenser 80, signal 81 and'grounded battery 82. In order that operators provided with sets such as- 70' and 71 may communicate withthe branch stations on line L, "there is placed before each such operator a ack 83, all of the jacks associated with the same line L being connected in multiple and to the wipers 12 and 13 of the selector switch associated with that.

are provided with each jack 83, all 'those signals which are associated with a given line L being connected in series with ground 11 in the proper.

\be provided to notify the central office attendants that such a selector switch-is overflowing so that some of the operators associated therewith may 'berelieved of a part of theirload; This result is accomplished "by connecting the last contact of the selector switch 10 through a suitable resistance 90, an overflow-.ofrelay 91 and an interrupter 92, to a grounded battery 93. Energization of relay 91 causes the flashing of an overflow signal 94 and, since the insulating segments of interrupter 92 are wide, as shown, the current from battery 93 through contact 14, wiper-13 and relays 41 and 47 is interrupted long enough to elfect the complete deenergization o:f these relays, causing the selector making connections as shown at 95, one overflow signal .may accommodate 'several selector switches.

i The operation ofthe system is asfollows; When any station on line L desires to make a call, key 6 is depressed closing a circuit for battery 38 through starter relay Starter relay 35 thereupon pulls up its arinatures 36 and 37; armature 36 closing a circuit for battery 38, through. magnets 31 and 30, contact 42 and interrupter 32. The arm 11 of the selector switch thereupon begins to ro tat-e in the direction of the arrow. The attraction of armature 37 completes a circuit for battery 38 through all of the busy signals 85, thereby notifying operators equipped with sending sets 70, 71, etc., that line L is busy, so that during the display of 47 and 41; Signal 28 becomes active, notifying the operator that a telegraphic conversation is desired and relays 41 and 47 at tracttheirlarmatures. The'pulling up of armature 45 connects line L to the idle operators set, through the wiper. 1-2. The attraction of armature 63 breaks'the circuit for interrupter 32 through the magnets 30 and 31, giving these magnets a steady ground, which stops the movement of arm 11 and holds the arm of the selector switch in this position until the call is completed. The pulling up of armature 61 provides a switch to return to its normal position. By

new, ground "for starter relay 35 through Y contacts 60 and 62, which as previously pointed out, became engaged upon the first step of the selector switch, and, since relay 47 is slower acting than relay 41, the attraction of armature 56 does not break one ground connection for relay until this new ground is provided through armature 61. Theattraction of armature 56 short circuits the two higher resistance windings 49 and 50 of relays 47 and 41, providing a lower resistance ground connection on the contact 14 associated with the operators set, so that if the selector'switch of any other line upon which a call is initiated steps upon a contact also connected to this operators set, insuflicient current will flow through the relays thereof which correspond to relays 47 and 41 to cause their energization to stop the movement of the selector switch. This arrangement insures that the selector switches will not step upon the contacts to an operators set which is already busy, but will pick out the first idle operator. Line L is now connected through to the first idle operators set, such operator being notified of this fact, by the lighting of signal 28.

Messages may be exchanged by the manipulation of keys 6 and 23 in the usual manner, and busy signals are displayed for all of the corresponding jacks 83 associated with line L. WWhen a call iscompleted, the operator depresses her release switch 22, whereupon the circuit through the windings 46 and 48 of relays 47 and 41 is opened, causing these relays to release their armatures. The release of armature 45 opens the circuit between line L and the operator. The retraction of armature 61 opens the holding circuit previously traced for starter relay 35, while the return of armature 63 opens the steady ground connection for magnets 30 and 31, and againconnects these magnets to the interrupter 32. The interrupter 32, however, cannot cause the operation of magnets 30 and 31 because the denergization of starter relay 35 has opened the circuit at armature 36. The deenergization of magnets 30 and 31 a11ows arm 11 to return to its normal ppsition, which condition should be obtained before the armatures of relay 47 are completely retracted. H1811 the armatures of .relays 47 are retracted, the apparatus is again in a normal position.

In case all of the operators associated with switch 10 are found in a busy condition, upon the initiation of a call upon line L, the arm 11 makes a complete circuit of all of the contacts 14, at last arriving upon the contact connected to the overflow relay 91. This relay will thereupon attract its armature to cause the flashing of overflow signal 94 and, the nonconducting segments of interrupter 92 being made sufficiently long to nets 30 and 31, in precisely the same manner as for a disconnection caused by the central oflice operator as previously described, whereupon, the selector switch will return to itsnormal position.

When one of the operators provided with a set 70, 71, etc., desires to be connected with a line L, the plug is inserted in the corresponding jack 83,, whereupon a circuit is completed from battery 82, through signal 81, plug 75, jack 83 and windings 46, 48, 49 and 50 to ground. Relays 41 and 47-pullup their armatures, as previously described, connecting the operators set directly through'to line L by means of armature 45 and contact 40, and operating all of the busy armature 55. When the telegraphic conversation is completed, the operator withdraws plug 75 from the jack 83, whereupon-all of the apparatus returns to normal.

The invention claimed is:

1. In a telegraph system, the combination of a telegraph line extending to a central office, busy signals and sending. sets associated therewith at the central office, selecting mechanism for said line adapted to automatically connect said line to one-of a plurality of operators positions, a pair of electro-responsive devices, circuit connections whereby said devices may be brought into action through said line or a said set, and means controlled by said devices to affect said busy signals.

2. In a telegraph system, the combination of a plurality of telegraph lines terminating at a central office; busy signals and sending sets associated therewith at a plurality of operators positions at the'central oflice; selecting mechanism for each'of'said lines adapted to automatically connect said line to one of a plurality of operators positions and comprising a selector switch having a plurality of contacts, and an electromechanical actuator therefor; multiple circuitkconnections extending between the contacts of different said switches whereby a plurality of said lines may be extended .to afsingle, operators position; a pair. of electrore'sponsive devices associated with each said mechanism; circuit connections therefor whereby ofiice, a selector switch automatically operaefl'ect the complete deenergization of magsignals 85 before other operatorsthrough telegraph line extending to a central tive upon the initiation of a call to connect I said line to the first idle operators position,

calling jacks and busy signals associated; l.

with saiai line at a plurality of operators my name this 5th day of December, A. I)

ositions, said bus si nals bein ooerated 1914. P .Y 1 q when a'cuai is initiated, and an o'verload slg- P v A I M. RAINFY. nal ngerated by 551161 selector swltch when all 51w OPGHHTOFS"130811710118 assoclated there- -Wltnessesz Wfl'h are m a. busy condltmn. E. EDLRR,

"in wiiiness whereof, I hereunto subscribe. K. L. SLAHL.

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