US1326212A - Telephoste-exchastge - Google Patents

Description

u. E. 14012313051; PARYY LINE TELEPHONE EXCHANGE. APPLICATION FILED MAR/0. 9i RENEWED APR. 22. $918.

- 2 SHEiTS-SHEET I.

Patented D66. 3

E. NORSTRUM.

PARTY LINE TELEPHONE EXCHANGE. APPLlCATlON FILED mmzo, 1910. 1,326,212.

RENEWED APR. 22. I938- P'umwa 1m. 30,1919.

2 SHEETSSHEET 2.'

.NN N MEN war.

STATE s PATENT onnion.

ITILSEMEL NORSTROM, OF CHICAGO, ILLINOIS.

Specification of Letters Patent.

PARTY-LINE TELEPHONE-EXCHANGE.

Application tiled March 20,- 1916, Serial No. 85,279. Renewed April 22, 1918. Serial No. 229,938.

To all whom it may concern:

Be it known that I, NIL8 EMEIENORSTROM, a citizen of the United States" of America, and a resident of Chicago, county of Cook, and State of Illinois, have'invcnted certain new and useful Improvements in Party- Line Telephone-Exchanges, of which the following is a specification.

My invention relates to party line telephone exchanges, and has for its object improvements in such exchanges.

In the accompanying drawings Figure l is a transverse section of a cen- I tral oflice keyboard suitable for operation in this exchange, only so much of said device being .shownas-js deemed necessary to explain the operations of the exchange;

' Fig. 2is an enlarged plan of part of the contact arms shown in Fig. 1;

. Fig. 3 is a side elevation of three of thecontact arms shown in Figs. 1 and 2;-

Figs. 4 and 5 are section and perspective,

" of the drawing, and lines leading to other local stations at the lower 'left hand corner.

The keyboard, or calling device, shown in F i 1 consists of a suitable frame hav ing tw rows of insulated keys 10 which are properly numbered to represent different stations on a party line. There is presumed to be one such keyboard at each operators position in' the exchange, but the dia ram illustrates connections to only one of t em.

Beneath each row of keys 10 is a shaft 11 on which are loosely mounted contact arms 114, there being one such arm for each key 10. Associated with eacharm'114 is a collar 12 secured to the shaft 11 by set screw 13. A spring 14 on each-collar serves to nor mally depress the inner end of the associated arm 114. On the lower end of the stem for each key 10 is a head 15 which, when the keys 10 are in elevated position as shown in Fig. 1, engages the upper end of associated arm'114 to push it outward and consequently to raise the inner end. When, however, a key 10 is depressed, the spring 14 connected to the corresponding arm 114 moves the inner end of the arm downward Patented Dec. 30, 1919.

andthe upper end inward so that the man, 16 dropsover the head 15 and holds the key" depressed until released as hereinafter do.

scribed.

In the. center of the calling device is a.

shaft 150 on which are spirally arranged? a series of wiper arms 115. These wiper arms consist of sheet metal 17 formed around blocks 18 held to shaft 150 by set screws 19. These wiper arms have the outer on shaft 150 so that each wiper arm may engage two, contact arms 114 as shown in Fig. 2. Each block 18 has its outer end cut away as shown at 20 so that the wiper arm will .make electrical connection with a contact end of the sheet metal. 17 curved as shown" a. i

in Fig. 5, and are arranged longitudinally" 7 As the shaft 150 advances step by step, i

a wiper 115 first engages a contact arm 114,

' (if it is at the time in a depressed position), v and then pushes the inner end of the arm upward to release the engaged head 15 and permit the depressed key 10 to rise to normal position. As the wiper arms are spirally arranged on the shaft 150, it will be evidentthat the number of steps which the shaft makes before a key is released will depend upon what key 10 is depressed.

The switching mechanisms at the local stations are of an ordinary and well lmown kind, and do not need description. However, there is a characteristic of such switching mechanism which calls for special notice because it has a bearing upon the operation 'at the central oflice. The matter referred to is illustrated in Fig. 6. The ratchet wheel 22 is mounted on the shaft 23 and is driven by a pawl 24. Adjacent to the wheel 22 are some contact springs, one of which carries a piece of insulation which engages a fiat-- tened part of shaft 23. The flattened part of the shaft acts as a cam to move the central spring from electrical connection with.

the upper spring to electrical connection with the lower one. The ratchet wheel has fine teeth and is operated by impulses sent from the central office. Owing to the finemass? of the teeth, one step of the ratchet wheel isnot enough to shift this connection with certainty unless the adjustment of the spring is made with extreme care. To overcome this difficulty in the ordinary local station switching mechanism and to avoid such extreme delicacy of adjustment, the calling device at the central ofiice 'is made so that it will never send out less than a plurality of operating impulses, no matter-what station may be called. 1

. impulse sender S driven by a motor genera-v tor MM, the current for operating which comes from a battery X. This battery is the regular central energy storage battery used in common battery exchanges. The impulse sender distributes impulses from the generator part M as will be described.

Also at the central office are a'generator 99, certain keys, magnets, contacts and connections, all of which will be understood from the description of the operation of the exchange.

It will be assumed that the subscriber at the local station shown in the upper right hand corner of Fig. 7 calls central,-and that the operator responds and makes the desired connection.

To call central, the subscriber turns the crank of his generator when a current flows: G 31;323334-35-36,373839 L041-4243.44-4546474819- 5O 51-G This operates drop 38 to call operator,

who inserts plug in jack and presses listen ing key K, whereupon the talking circuit between'calling subscriber and operator is as follows: receiver at local station S 52 hook53-54553F135-36 56plug and operators set4546 474849 5051-receiver.

To call another subscriber on the same party line, the operator presses the key 10 on her calling device which corresponds to the station to he called. She also presses key K. The completed circuit is :X-57" 58- 59-606162-Coil A'63--ground X. Coil A shifts the contact springs above it to complete a'circuit for the motor M as follows :X56-5758-59-6061 6264.65-66-Mgr0und-X.

The motor M drives the l00-volt dynamo M and the impulse sender S. From these impulses flour to operate magnets C and D, and the stepping up coils at the local stations, and a corresponding stepping up deviceat the central oflice. The first circuit i's":M 676869-70ground to the local stations on the linc71-7248- '474645-73 7=l 5 7 67 7 -78-7 9- There is also a branch to ground at central through magnet 87 and wire 88 to-45 where it joins the previous circuit. The impulses in this case are in the release direction through the stepping up magnets, the'ob ject being to insure that all switching mechanisms at the local stations, and the corre sponding one 87 at the central office, shall be in normal position when stepping up impulses begin.

- The first impulse through magnet D closes 90 to 91, when a circiiit is completed as fol- 9'2groundX. Magnet B closes ground connection for itself at 93-94, so that it is independent of the connection closed by D,

and also closes for C a circuit as follows tion to engage an contact arms-114 w ich may have been cpressed by the operator pressing one-or more of the keys 10. On the shaft 151 is a loose arm 162 located between and driven by twopins on the wheel 151. There is a little pla between the arm 152 and the pins in the wheel so that two or more steps will be made by the wheel before the adjacent pin thereon engages andmoves the arm 152 from its normal position., The arm 152 has, on its outer end, a piece of insulation on which rests the end of the spring 80 when the arm is in normal position. When, however. the arm 152 has moved from under spring 80, electrical connection shifts from 81 to 98. In this condition therelease impulses previously described as passing from 80 to 82 by way o'f.8l will thereafter pass by way of the resistance R. These release impulses through resistance R continue, and alternating with them are operat ing impulses as follows :M?67-68-69- 96--97988079., and so on over the same circuit". but in the. operating direction through magnets 71 and 87. In other words, operating. impulses and release impulses flow alternately from the dynamo M through the ste ping up coils. The operating impulses are full strength, while the release impulses flow through the resistanceR and have only sufficient strength to neutralise the residual magnetism in the coils and assist the reverse movement of their armatures.

During this operation, magnet C continues to receive operating impulses which are simultaneous with the release impulses through the stepping up coils, but which pass around resistance R. These impulses through C advance shaft 150 and wipers 115 as before described. If we assume that the -key 10 on the keyboard which the operator iaq then, after the stepping up coils have made their ninth step, magnet C brings the tenth wiper 115 into electrical contact with the tenth contact lever 114. This electrical connection remains while the stepping up coils make their tenth step, immediately after which the next step by magnet C causes the tenth Wiper to push up the tenth contact lever 114 tobrealr the electrical connection at this point and permit key 10 to rise.

At the local stations, each forward step. causes spring 32 to engage spring 106. and at station N0. 10 the tenth step cause; arm 118 to push spring 104- into engagement with contact 103. When this occurs, it ourrent fiows:-generator is at central-100- 63-ground to local station No. 10-cut-in coil lO1l02-103104-10510632r33 i3435-36--5 i-1O7--- 198 109 110 1111l21 13-114 115 116117--99.

At the beginning of the stepping up movements at the local station, the cam on shaft 2?; moved spring ,50 from electrical connection with spring 49 to connection with contact 134. A similar action also occurs for switch 87 at the central olfice. At the differout local stations on the line, the arms 118 move spring 104 in succession, one at each step of the switching mechanisms. Consequently the nnpulse last described for operating" the lock-in coil 101 goes only through the selected station No. 10. The operation'of this coil shifts the electrical connections just above its armature and thereby connects the selected stationtelephonically to the line.

The rise of key No. 10 on the calling device breaks the circuits, either directly or indirectly, for the magnets A, B and and the motor M. The operation of the-switch 87 at central, howeverpprovides another circuitas followst-X1.19120121-122 1:23l24125 -6(3-M-gro1xndX. T he lampv 124" in this circuit provides resistance which permits the-motor to continue running, but atareduced speed.

hen the circuit. through magnet A is broken as described. the contact springs moved thereby return to their normal position, whereupon a current flows :--99 "l0f}- 12e 12777- 7c-75- 74-73 r +c -4? scriber, and the ringing continues as longas.

In the lower part of Fig. 7 is; shown a.

plug! l? adapted to be inserted in a jack J c-(l to another part line L. It will {al that with plug l in jock J an 2y on line L might he called by the .r c j*:-.-.- il'=s(:ril ed. lVith both plugs in their ing-out drop 138 to inform the operator that y the conversation is ended.

The operator removes plug from jack to permit 45 to close to 44, when a current flows:M -6768 (i9 70-ground to all local stations on the lineT1-7248-47 46 -45-4443-4241-14-2143 144 82Q384,85-86 M There is also a branch through 87 to 44. These impulses are, at filst, of low voltage, due to the slow running of the motor as before described. The armature of switch 87, however, isarranged to have play between stiff springs so that the low voltage from M may move the armature far enough to close contact 145. This closure shunts the lamp 124 so that the motor may get full voltage from battery X. This permits the motor to ingiven circuit, which impulses are in the release direction. The central office switch 87 is provided with an unusually heavy ratchet wheel, or other heavy moving parts, so that it will be more sluggish in its release action than are theswitches at the local stations. This permits the switches at the local stations to return to normal position sooner than switch 87. Upon release of switch 87, the motor circuitis broken at 121-122, and the motor 'stops. The same release also bridges the drop 38 by closing contacts 40---l1. The contacts 40-41are used to cut the drop 38 from the line so that contact 44 may he used to carry release impulses upon removal of the plug without causing the drop 38 to flutter. f When a call is made on a party line, all stations on the line have their springs 50 moved from contact 49 to contact 134. At the called station, the lock-in coil-10l-has been operated. At uncalled stations the contacts operated by this coil are in their normal position. If an uncalled subscriber attempts to call central when the. line 15 busy, his generator will be shunted as fol lows :-G 313Q3355-54 53;-145 133134--'5O-51.G If. however, the subscriber should press his emergency key 54, the shunt would be cut out and the circuit would be through the clearing out drop 138 as given for ringing off, except last part which is I47l48t-1601615i-53l45 133-13i 50-51--G It will be observed that the shunt just given for the magneto or generator (al con- .tainsno resistance when the line is busyv emergency button not pressed. Under these circumstances no current would flow, and the difference between no current and the small amount necessary to call central is not enough to indicate by feeling that the line is busy.

At the upper part of that portion of the drawing which shows the local station are two binding posts-300, and farther down on the drawing are four binding posts 301. .The apparatus included between binding posts 300 and; binding posts 301 is thc lockiut apparatus, and is inclosed in a locked and sealed case or box.- The apparatus below binding )osts 301 is that contained in the ordinary telephone box. The party line connections are made at posts 300, and posts 300 and 301 are secured to the ease containing the lock-out apparatus.

Emergency keys, such as 54, have heretofore been used in party line exchanges, and to prevent an uncalled subscriber from listening in on the line by pressing this button, there has been provided a shunt for the receiver. This shunt has, heretofore. always been one of the exposed wires extending from the case containing the look-out apparatus to the telephone box. As this wire served nopurpose other than that of shunting the receiver in an uncalled station, it was always possible to release it from one of its binding posts without disturbing the operation of the apparatus or giving any appearance of change. By so doing an uncalled subscriber could press his emergency key and listen on the line. The reason .why this has heretofore been possible is that 'the emergency key was placed on the same side of the line as the contacts operated by the cut-in-coil, (open at all uncalled stations), and was used to close :the' circuit around those contacts to enable the subscriber to send a magneto current to central. Prevention for listening was due solely to the shunt which a subscriber might releaseor cut because exposed.

In the present case I have removed the emergency key to the other side of the line so that it does not close the circuit around the contacts operated by the cut-in coil, and use part of the talking shunt as part of the magneto'circuit for calling central. This talking shunt in an uncalled station is: Re ceiver S- 52 -531l5133-13-l50 5l-receiver. Cutting the. shunt connection 115 would cripple the connection for emergency calling without enabling the uncalled subscriber toflisten on the line because the emergency key does not close around the open connections. Consequently lmay place this shunt 145 in either an exposed or an unexposed position withoutaffording means by which an uncalled subscriber may listen on the line. I have, however, placed it entirely within the sealed box containing the lock-out. apparatus. which heretofore could not be done.

Returning now to the impulse sender b, it will be seen that this is a device for supplying or sending alternating impulses to ground, and for separating the impulses so that plus impulses are sent over one line I and minus impulses over another line. Thus, if we consider impulses as flowing from the sender, positive impulses would flow from the brush 96, and negative impulses from brush 83. One keyboard having keys 10 and 10 is shown as connected to the brushes and 83, and to the battery X. l t will be evident that the inipulses flowing from the sender and controlled by the kerboai'd are not influenced by the presence orabsence of another keyboard connected to brushes 96 and 83, and battery X. Consequently, other keyboards with their associated parts may be connected to the same brushes and calls may he made simultaneously over other lines without causing confusion. Connections completed are shown for one 'keyboard,-and other connections are shown at 302 which may be extended in the'. same way to another keyboard. In the construction and arrangement shown, one impulse senders, and one stepping impulses may flow over one line and simultaneously therewith release impulses may flow. over another lineal] impulses coming from one and the same sender. The, keyboard also governs the flow ofimpulses over the line so that release impulses of reducedstrength will alternate with the full strength stepping impulses.

In calling over two lines at the same time,

esser-.2

vplugs 73 -107 and P are inserted in the oi the respective lines, and the lreys ii?- and K are In this condition step-- ping up coils of both lines are connected toetlier throu h the tip sides of both oluus i" 1. a 7

line through the wires lb. Consequently, each impulse operates over both lines to produce simultaneous operation of the stepping up coils on both lines. Heretotore, when calls were made over two lines, impulses were sent alternately, first over one line and then over the other. The present arrange- .ment which connects the two lines as describedsaves in time required for calling and also in equipment.

' While pressing both lreys K and K connects the tip sides of plugs together, that action separates the sleeve sides. By referring back to the circuit from generator through the cut-incoil 101 it will be seen that that circuit goes through the sleeve side 107 and the contact arm 114: controlled by similar circuit may be traced from the 0. other so that" a contact made by one wiper the key 10 on the keyboard. A precisely sleeve side of plug P to the contact arm 114. on the opposite side of the calling de vice. The contact arms 114. on one side and 11 on the other-are insulated from each "115 to send out an .impulse through. the sleeve side of one plug does not necessarily involve a similar impulse through the other plug. If th contact arms are d rectly opposite each other, then the w1per 115 will connect to both at the same time and cut-in impulses will flow over both lines at once. If,

however, the contact arms 11% and 114" which are depressed are at different longs. tudinal positions in the calling device, then they will be operated by different wipers 115.

5. What I claim is:

1. A source of alternating impulses, a. party line over which such impulses may flow, a calling device arranged to control the distribution of the impulses to the line, and means for controlling the calling device by theimpulsesu I 2. A source of alternating impulses, a party line, a calling devicarranged to distribute the impulses from source in a' and the impulses from the sender .6 come to center of tlns connected- .stations on both lines.

predcterminied arrangement to the party line, and means for operating the calling device by the impulses.

3. A battery, a motor-generator driven thereby, a calling device operated by impulses from the motor-generator, and means by which the calling device controls the number and distribution of impulses from. the motor-generator.

4:. A battery, a motor-generator driven thereby, a circuit over which a current may flow from the generator, a commutator driven by the motor. and serving to transform the current from the generator into alternating impulses flowing over the line, and nieans'controlled by thecommutator for re-' ducing the voltage ,of each. alternate impulse.

5. A battery, a motor-generator driven thereby, a calling device, a circuit over which impulses from the motor-generator operate the calling device, a party line arranged to receive impulses'from the motorgenerator, and means by which the calling device controls the impulses to itself and to the party line. 4

6. The combination with two p'arty lines.

eachhaving .a plurality oflocal stations thereon and each station having a step-bystep mechanismconnected to the line, and

a cord connecting the .two lines, of a source of electricity connected to one side'of the cord, and means by. which impulses from said source are caused to flow over both lines simultaneously to cause all step-by-step mechanisms of both lines to move in-sync chronism; v

7 The combination with ously connected to bothlines, of a wire connected to the connecting side of the cord, 9. source of electricity, and means by which impulses from said source are caused to flow over said wirean cord to cause simultaneous operation or, ectrical apparatus at all 8. Two party lines'each having local stations with step by-stepapparatus thereat, a central ofiice to which said lines are connected, an impulse sender at said office, and means by which each impulse from said sender causes'the same operation of the step-by-step apparatus of all" stations. of both lines.

9. The combinationiwith twoparty lines,

an impulse sendenjafcalling device control- I hug the impulses from said sender, anda.

generator, ofa cord serving to connect the two lines, means by which ones1de of sald I cord connects corresponding branches of the two lines together so that impuls'esirom said' sender will flow alike ove1.'the connected branches, and means by whichtlieother-side two party lines," and a cord having the same -side simultaneof saidcord' separates thebther branches of the two lines soth'atimpulsesimm said generator will flow at different times over the separated branches.

a source of. alternating impulses, and a calling device for distributing such impulses in a predetermined manner to said lines, of a cord provided with means for connecting together corresponding branches of each line and separating other branches, connections from the calling device to one branch of the cord so that given impulses will flow simultaneouslyIover the connected branches, and other connections from the calling device to the other branch of the cord so that impulses will flow at different times over the separated branches.

v11. A party line terminating in a jack in a central ofiice, switching mechanisms at local stations on the party line, a special switching mechanism at the central ioflice and also connected to the party line, a line drop at the central ofiice and operable from the stations on the line, means by which upon insertion of a plug in saidjack operating impulses may be sent to all of said switching mechanisms, means by which release impulses are automatically sent to all switches upon removal of the plug from the jack, and a connection for said drop controlled by the special switching mechanism so thatthe said drop has its circuit broken during the sending of such release impulses.

12. The combination with a party line provided with a jack in which a plug may be inserted and removed, and a line drop operable from local stations on the line, of means for sending impulses over the line when the plug is not in the jack, and means by which such impulses are prevented from affecting the line drop.

13. A plurality of party lines extendlng to a central ofiice, a source of alternating ims,

pulses at the central ofiice, said source being provided with connections to a plurality of. calling devices, a calling device attached to: a pair of such connect1ons,'a cord connecting the calling device to one of the party lines,

and means by which the impulses recelved by the calling device are modified and distributed to the line to which it is connected independently of the manner in which the same impulses are modified. and distributed to some other line connected to some other calling 'device' 14. A party line.'switches connected to the party line and advanced by impulses in one direction and released by impulses in the other direction. a source of alternating impulses, means by which upon connecting said sonrceto'thc line impulses of full voltage in the release direction will flow through said switches, and means by which upon the'completion of a small number of such impulses a resistance will be automatically placed in 10. The combination with two party lines,

the circuit for such impulses and other im pulses of full voltage in the operating direction will alternate with the reduced impulses in the release direction.

15. A party line, a source of alternating impulses, means by which upon connecting the line to the source impulses in one direction will flow over theline, and automatirally operating means for inserting resistance between the source and the line upon the completion of a predetermined number of impulses.

16. The combination with a party line, and means for sending electrical impulses thereover, of means controlled by the impulses for reducing the voltage of all impulses following a predetermined number of impulses.

17. A central office, a party line connected to the central ofiice and having lock-out apparatus and a receiver at eachone of a plurality of local stations on the line, a connection at each local station serving to shunt the receivers at stations locked out, a genorator at each local station,a signal at the central oflice adapted to be operated by the generator, and a manually closable circuit for said generator and signal, said circuit being composed in part of the shunt for the receiver at the same station.

18. In a lock-out'party line system. hav- .ing a central oflice and a plurality of local stations on& a party line connected thereto, a "telephonic shunt for each station locked out, a generator at each local station, and a manually operated emergency connection for completing a signaling circuit from a locked out station to the central office, said circuit being composed in part of the telephonic shunt for the station.

19. In the local station circuits of a party .lme system, binding posts 300 serving as connections between the line and the local station, other binding posts 301 serving as connections to the normal local station telephone apparatus, and a telephonic shunt for the station consisting of a connection lo cated between posts 300 and 301.

20. A party line terminating in a jack in a central office, switching mechanisms at local stations on the party line and advanced by impulses in one direction and released by impulses in the other direction, a special switching mechanism at the central office and also connected to the party line, a source of, electrical impulses for op'erating all of sa d mechanisms, and automatically operatmg means by which all impulses flowing from said source over the line will be in release direction when the jack has no plug therein.

21. A party line. terminating in a jack at a central oiiice, switching mechanisms at local stations on the party line and admadam 7.

vanced by impulses in one direction and released by impulses in the other direction, a special switching mechanism at the central oflice-and also connected to the party line, a source of electrical impulses for opcrating all of said mechanisms, and means by which upon said special mechanism l)('- ing advanced from its normal position when the jack has no plug therein impulses from said source in release direction will he antomatically sent over the line.

' 22. A'p'arty line connected to a central office, switching mechanisms at local stacuit without affecting the shunt for the talking circuit.

23. A party line connected to a central otlicc, connections at each station on the line for establishing magneto and talking circuits for the station, means controlled from the central ollicc for establishing a separate shunt for each circuit, means under the control of a subscriber for cutting the magneto shunt at his station, and means. under the exclusive control, of an operator at the cen traloflice for cutting the talking shunt.

24. A party line connected to a central ofiicc. a nmgncto at each station on the line left means f which the subscriber thereat may call the central ofiice, and means controlled from Ihc central otfice for connecting 'a selected station telephoiiically to the line and for' establishing a shunt at each other local station for the magneto thereat, said shunts having no resistance therein other than that existing in the connections forming them.

Signed at Chicago, 111., this 18th day of March, 1916.

NILS EMEL NORSTROM.

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