US991260A - Automatic telephone system. - Google Patents

Description

Patented May 2, 1911.

JIIZ/Elllfll' krfinflexeeflf W V. ALEXEEPF.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED JUNE 19, 19011.

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V. ALEXEEFF.

AUTOMATIC TELEPHONE SYSTEM.

APPLIUATION FILED JUNE 19, 1908. r 991,260. Patented May 2,1911.

9 SHEETS-SHEET 81 Fig Wl'ln ss s: A

V. ALEXEEFF.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED 111N319, 1908.

EB H

is 6 2 ioz'z'zzy V. ALEXEEFP.

AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILED JUNE 19,1908. 991,260. Patented May 2, 1911.

9 SHEETS-$111313 G.

m Hill 1 ii ii V. ALEXBEFP.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILLED JUNE 19,1908.

991,260. Patented May 2,1911.

9 SEEETSSHEET 7.

V. ALBXEEFF.

AUTOMATIG TELEPHONE SYSTEM.

APPLICATION 11.21) JUNE 19, 1908.

Patented May 2, 1911.

9 BHIIETSBHEET 8.

I I/127255555 in. Winn-Jib you.

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V. ALEXEEFP.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION TILED 11111219, 1909.

Patented May 2, 1911.

9 SHEETS -BHBET 9.

THE nouns VITIRS cc, wAsmua-ron, on;

VALERIAN ALEXEEFF, OF ENSELI, PERSIA.

AUTOlVIATIC TELEPHONE SYSTEM.

99] ,Tdtit).

Specification of Letters Patent.

Application filed June 19, 1908.

Patented May 2, 1.911.

Serial No. 439,331.

To all whom it may concern:

lie it l\'lt()\\11 that. I, V.'\|.r: |u.\. .innxnnrn a subject o't-thev Russian lhnpcror residing at lluscli. lersia. have invented a certain new and usetul Automatic 'ilelcphone Hy t-eiu, o't which the following is a Hl'lttfltlt'tP tion.

The. invention relates to antounltie tolcphone systems which allow each subscriber to directly obtain tfiiillttllOll with another subscriber, without calling up an exchange oli'icc tor mattingtnisconnection,and consists in a construction which enables the ((lill'ltt tion. to be obtained quickly and withoutthe necessity of employing a complex system of conductors while. at the same time, other persons are prerented from hearing the conversation. The number of subscribers may without inconvenience amount to approximately four hundred. The whole system is arranged in such a manner. that in the case of only a small number of subscribers there is provided a selecting-switch station, to which the telephone of each subscriber is joined. In the ease of a greater numl-ter of subscribers. the telephones of the subscribers form groups. each at which has selecting-switch substation and the connection of subscribers of diii erent groups takes place over a. cei'itral selecting-awitch station. to which are joined the selecting-switch substations of all groups. The new system is peculiarly suitable for private establishments, small towns and villages.

In the drawings are shown arrangennnits for 10 and 100 subscribers.

Figures 1 and 2 are vertical and horizontal sections respectively through the auto matic central selecting-switch station asused in the case of agreater number of subscribers for connecting the selecting-switch substat-ions of different groups. F 3 shows part of the internal mechanism. Figs. 4 and 5 illustrate on a larger scale the co-action of the automatically adjustable contact plates of the central selecting-switch station. Fig. 6 is a. horizontal section of the slide-contact cylinder. Fig. 7 is a semi-diagrammatic plan view partly in section illustrating the working of the pawl upon the rotary disk. and Fig. 8 is a vertical section of part of this mechanism. Fig. 9 is a vertical central section of the selecting-switch station of each group of subscribers. Figs. 10 and 10 show the sliding-contacts of the selecting switch station of Fig. 9 on a larger scale. Figs. 11.

and 12 are vertical sections oi; the particular circuit closing mechanism belonging to a subscribcfs instrument. Fig. 13 shows the reversing lacy with contacts and connections. Fig. 14- is a vertical section of an optical indicator associated with the. circuit closing mechanism. Figs. 15, 16 and 17 illustrate the connections when the calling telephone (Fig. '15) is to be connected to the called telephone (l ig. 17) through one single select hug-switch station (Fig. 1(3). Figs. 18 to 2). illustrate the connections when the calling telephone (Fig. 22) through its selecting switch (Fig. 21) is connected by means oi the central selecting'switch (Fig. 20) with the selecting-switch (Fig. 19) of the subscriber to be called (Fig. 18) and through this latter switch with the corresponding telephone. Fig. 23 is a diagammatic View illustrating the connections between several stations of the system.

In the. central selecting switch (Figs. 1. and in the annular wall of the casing M and in two superposed rings D and E there are bearings for two superposed groups of radial rods C C C 0 To the rods are. fixed eleetroanaguets B B B l3 and small contact-disks 0 The coils of the electro-magnets B are excited by current from a local battery VII (Fig. 20), as will he explained hereinafter. Electro-magnets A A A A are supported in the easing M in radial line with the magnets B 13 respectively, but the rods C C pass through the cores of the electro-magnets A without making contact therewith. The electro-magnets A can be excited by currentfrom the. line wires (Fig. 2-0). The casing M and ring D are of electrically non-conductire material: the ring E is conductive, but is insulated from the rods C C by non-conductive sleeves a. Two superposed pairs of electro-magncts A and B belong to the same subscriber. Springs 0 on the rods (l C tend to thrust. the latter toward the center of the casing M and move the cores of the magnets B B away from the cores of the magnets A A The two magnetic forces and the force of the springs are so proportioned, that any two of them acting collectively overcome the third force. In the position of rest shown in Fig. 1, with no connections made for the transmission of telephonic messages, the. magnets A and B are in contact with each other, for reasons which will be explained hereinafter. Separation of the respective electro-i'i'iagnet B from electro-magnet A takes place only when the corresponding magnet- A is excited by current from the line. If one of the lower electro-magnets B (Fig. 1) is repulsed. from its electro-nIagnet A, when the latter receives current il'n mlses from the calling-telephone, it brii'igs the con-- tact-disk 0 into contact with the ring R. The contact ring a on the upper rods C? 0 remains, when displaced by the magnet B, in contact with the respective contact-piece (Z (1 ot the ring 1). At. the outer end of each of thelower rods C C there is a. knob or button 0 with a recess c therein, and near the said knob or button there is a slidable disk a normally thrust against a fixed disk by a spring 1".

Between the upper and lower magnets T3 (Figs. 1, 4 and 5) there are two slide-contacts 7) and F2 The slide 6 consists of three metal plates 6 b and Z) of different widths. The plates 6 and b are connected to a positive wire, and the plate 6 is connected to the negative wire of the local battery VII. (Fig. 20). The slide 71 cons'sts of two contact-plates b and Z), to which the coil of the lower magnet B is connected. No connection can be made to the said coil other than through the contact-plates Z2 and I). It will be seen from Figs. at, and 20 that by displacement of the magnets and slides relatively to each other the direction of the current in the lower magnet is reversed, the flow being either from b to o and from Z) to Z), or from b to Z2 and from b to b, the contacts 6 and 6 being electrically of the same sign. The slide-contacts are of such a size, that the lower electroanagnet B never becomes free from circuit, whether the upper electro-magnet B is displaced against the lower electro-magnet B, or contrary. The upper electro-magnets B, are connected to the local battery VII, from which they receive their current. Around about the easing M there are arranged outwardly respec tively above and below the lower group of rods C C two contact-rings c and c with which the disks 0 make contact when the rods G (3 are moved inward.

The upper and lower rods C C are connected in pairs by non-conductive links 9 and metallic bell-crank levers G G to a slide-rod F F (Figs. 1 and 3); the levers G and rods F are marked, in the drawing, with indices corresponding to the indices of the respective rods C. In the normal position of rest, shown in Fig. 1, the inner ends of the levers G connected to the lower rods C abut against the flange of an annular contact E within the ring R, but when the magnets A and B are thrust apart, the levers G go down and their contact with the part E is broken. The contact E is connected with the earth and insulated from the ring E. Each of the rods F F 20 consists of an upper metal part 7 and a lower non-conductive part f, and the said rods are movable in guides 71, 72, within an axially movable non-conductive cylinder H. The guides k 71 are fixed to the cylinder 11 and their lower ends slide within a fixed, non-conductive cylinder J; the latter also contains movable plates Z1 2' which are supported by springs i, and against which the rods F F'- can abut. The movable cylinder H has a double bottom J*, to which is fixed the armature J of an electro-magnet J so that the cylinder H can be moved by means of the mag net J*. A spring J" tends to retain or to bring back the cylinder H in the normal position in which the said cylinder is shown in Fig. 1. The noninsulated part of each rod F F is normally (Figs. 1 and 8) only to a very small extent in contact with the respective guides l2. h so that a very small movement of the cylinder H relatively to the rod F is sufficient to produce a change of connections. To the guides h?" are connected wires it. leading to terminal-screws K K at the wall of the casing M.

In obtaining connection between two telephones, for the purpose of conversation, first the slide-rod F belonging to the calling telephone is moved downward, and then that belonging to the telephone of the subscriber called up. The other slide-rods remain at rest. For this purpose an arm M carrying an electro-magnet N is rotatably mounted on the casing and provided with fingers m m adapted to engage behind the disks a so that these fingers prevent the displacement of these lower rods C F opposite which the magnet N is placed. A brush a to which the coil of the magnet N is connected rubs on the contact ring 0 fixed to the casing M (Fig. 1). The magnet N is traversed by a movable iron rod n with a disk a fixed thereto, and a spring 99. tends to thrust this rod outward. The coil of the magnet N is also connected to a contact-ring a rubbing against a brush a which is connected to the coil of the magnet J Excitation of the magnet N causes the disk at to be attracted so that the inner end of the rod n is thrust into the recess 0 in the knob 0 with which the rod 12. is in line, so that the arm M is locked in line radially with the respective rod C C The rod of thrusts the respective lower magnet B in ward until the disk 0 on the rod C comes into contact with the ring E. From the magnet N the circuit is led through the brush a to the contact ring 0". The contact ring 11, receives circuit through brush a from the magnet J whose one coil-end is connected with brush a while the other coilend is lixed to battery I. The other pole. of battery 1 is connected with the ring 0 which can be eltaatrically connected to the ring a by the disk 0 (Figs. 1 and ltotation ol, the arm M in one direction (Figs. 1, 7 and 8) is produced by means of an electro-1nagnctie device, and in the other direction. by a. weight .l. attached to a cord 1. which is fastened to the hub or boss ol the arm M and passes over a roller l. The

eleetro-1nagnet ic-device referred to ((1111- prises a pawl 0 connected to the sliding-core o of an eleelro-nmgnct. and adapted to engage the toothed upper surilace of a ring or flange M fixed to the boss of the arm M; The clectro-niagnet O, which can be excited by currenttroni the line wire, is rotatable about a verti -al'pi\'ot 0 and. can he automatically rotated to and from the ring by two solenoids 0 and 0, a spring; 0 and battery Ill. The armature ol the mag net- U, consisting of a rod 0 with a disk 0 fixed thereto, is acted on by a s "'ng o. Fixed to the magnet O is arm 0" l u'catml at its free end to engage a pin 0" fixed to the armature o of the solenoid 0'. The solenoid 0 fixed to the casing lit, and the solenoid 0 is fixed to an iron rod 0 which projects from the armature 0 and passes through the solenoid 0*. The spring 0 tends to thrustthe solenoid o away from the casing M, but the solenoids 0 and 0 acting together, are able to overcome the force of the spring 0. The coil of the magnet 0 is connected to the battery II (Fig. 20). To the U-shaped armature o is pivoted a pawl 0, which enters sin'niltaneously with the pawl o" in the toothed ring M as long. as magnet is pushed outward by the spring 0 and prevents the returning; of arm M by the weight- P while the pawl o engages the next tooth of ring M The solenoid 0 is in a circuitconnectcd to the battery III. This circuit can be opened and closed by means of a cam m on the ring M (Fig. 7) and resilient contacts m m which are only held apart by the cam when the ring M is out of action, so that immediately after the first pawling of M solenoid 0 is excited and remains so when the parts are in a position for corn'ersation. The arm 0 makes an angle with the pawl 0 and when the armature 0 and arm 0 are moved inward toward the casing M by reason of excitation of the solenoids 0 and 0 the pawl 0 is pushed on to asmooth part of the ring M the magnet- 0 being rotated at the same time. The weight. P tends now to turn back arm M in its initial position, but this movement is prevented, because simultaneously with the solenoid 0 the magnet N is excited and its rod 02 is pushed in the hole 0 of the button 0 (Figs. 1 and 20). When the circuit of battery I is broken and thereby the attracting force of magnet N upon its armaturc n is suspended, the rod n is pushed out. of the hole a by the spring a". New arni lVl can beturned baclt stationary by the weight l". Although solenoid o is shut. out simultaneously with magnet; N the former remains by inllucnce oil. the solenoid o" against the ellect of springo". 'lhereby the pawls o and 0" cannot enter the teeth o't. M during the returning o't arin hfl'.

\l'hcn arni M. and also magnet. N reaches its initial position cain m. pushes the spring 11/," 'l l()tll the contact m (Fig. 7), breaks the circuit o'lf battery Ill. and renders solenoid 0 not excited, so that the attraction between 0" and o is suspended and spring o pushes solenoid o, and the pawls and 0 outward in the toothed part of M. Repeated closing and opening of the circuitv containing: the coil of the magnet: causes the armature o to be repeatedl attraettal and releasml again, and the ring ill is rotated, to the extent oil one tooth. as often as the armature c is attracted. The number of teeth of M is such that magnet N by each .t'ull turn o1 a drum V, hereinafter more particularly described brought by magnetfrom one pair of nuts-net's A. and B to the next one. Starting from its normal position magnet stands therefore after sir; turns of drum V before the magnets A B. The line wires which connect the magnets A ...A have respective ends connected to the contact disks while the remaining ends are coir neeted to the rods F .F The return is for the upper magnets :L from the contacts d (1 through the coil of the magnet O to earth. The return is for the lower magnets it over the grounded ring E, which is toilched by the lerers G in the position of Current from the local battery VII flows eontiiniously through the coils of the upper nnignets 1:3, and through the coils of the lower n'iagrnets ll in different directions depending on the position of the plates and b.

Fig. 0 shows the selectingswiteh, which must he enu'iloyed for each group of subscribcrs. and which. marly equal to the selectingswitch shown in Fig. 1 serving to connect the several groups. The diit'erences between the switches of Figs. 1 and 0 will now be described. The ring I? in Fig. 9 substituted for the ring I) of Fig. 1., is of metal. and the holes 0 therein for the passage of the rods (1 C lined with insulating inalerial. The contact-plates (Z HJZ in Fig. l) are lixed to the casing M and are so narrow that they do not remain in contact with the disks during the entire movement of the latter. hen the said disks are in contact with the ring 1*), current flows through the latter. The upper rods C" C have disks (1 fixed to their outer ends, adapted to abut against and electrically connect rings and Q2 fixed to the wall of the casing M.

One of the disks 5 also serves as armature for a magnet Q. which is placed on an extension of the. rod (1 slidable. in the said magnet and serves to connect the selectingswitch of one group of subscribers with the selecting switch common to all groups. ()no tern'linal of the coil of the magnet Q. is connected to the ring and the other to a terminal of a local battery 11. The battery ll is ccnnected to the ring so that the elect110-magnet. Q is in a sluint-circuit of the battery ll. in their positions of rest the levers 2 (R belonging to the upper rods O are in contact with a disk 0 fixed to the 1nagnet-core l of electro-magnet J. The slide-contacts for reversing the current in the lower coils li .ll' work as those of Fig. 1 and the magnets 13 are connected .in equal manner as in. the switch of Fig. 1, only the size of their slidiilgsurtaces differs from that of Fig. 1 in such a manner that the lower magnet l is short circuited and receives no current when the lower magnet 15 is adjacent. to magnet it but, the correspondinn upper magnet B is repulsed from A. (Fig. 9).

its shown in Figs. 19 and 9/1 the line circuit passes from the terminals KRHK over the sliding rods h- ...h and the rods FRUIT through each magnet-coil A to upper and lower rods (P-HIP". Now the route of the current dif ers from that of Pig. 1 as it passes through the lower electromagnets A, orer the contacts (Z (1 and through the magnet O of the driving pawl to the groin-nil, while the upper magnets A are connected with the ground over the levers G ...G- which touch in their position of rest the grounded annular contact F Current from the local battery 11 flows (as in the switch of Fig. 1) through the coi s 0 J and N. The battery 11 also feeds, as aforesaid, the electro-magnet Q, to which it is connected by separate wires. Another battery IV supplies currentto the solenoid 0*, as at the switch of Fig. 1. If, as aforesaid, in the case of a small number of subscribers, only one single selecting-switch has to be used, it is only necessary to change the apparatus shown in Fi 9 in such a manner, that magnet Q is omitted, as its function of connecting; the selecting-switch of one group with the selecting-switch common to all groups is unnecessary. The upper electro-magnets A B may also be omitted, because, as hereinafter described, only the lower magnets A B are needed. The con tacts b b 72 are not movable.

A switch-board (Fig. 11) has a series of contact-plates 1' 1' 7...and a hand-lever R. In a box fixed to the board there is a cylinder V of nonconductive material, which is fixed to a spindle V and carries a metal ring o with teeth o .71 A brush i is in continuous contact with the ring,

and a brush i is so placed that during r0 tation of the ring it alternately in contact with teeth 0".. '0 and with the non-conductive cylinder V. The brushes t" and Z are connected to the line. Behind the cylinder V there is a key S of non-coinluctive material, normally thrust upward by a spring .5 To the shank s of this key two eontimt-plates s and a (Fig. 13) are symn'ietrically fixed, which are connected with the line wire battery V (Fig. '15), and are i'ioij'nially in contact with contacts and Z under the influence of spring s. it the key S is struck the contact-plates a and 5" are inon'ientarily thrust against contacts 25 and 5' below them. The contacts t, 2?, t Ware as is evident fron'i Figs. 15 and 'l 1' connected with each other and with the line wire in such a manner that the current flowing to the contact-plates a and s" is for a moment reversed in the line wire it the key S is struck.

To indicate \Ylflifl'lltl the key S has been sutliciently depressed to reverse the current, two pairs of fixed solenoids a. w and springs 3 (Fig. 14) are provided for the connections of the same group selecting switch and for the connecting to other selecting-switches. The cores of these solenoids more in accordance with the direction of current, and cause ditferently colored disks to alternately appear behind. windows :7; for example, white:N-o call; blue: Short distance call; red: Long distance call. The manner in which the solenoids a0 and m co-act with the springs 7 is similarly to that already described in connection with the devices A B (2 and 0 0 0 one of the sole noids being fixed and the other movable wit-h the core, which is thrust in one direction by the spring. The movable solenoids are connected to battery VII, and the fixed sole noids to the line-circuit of the battery V.

Each of the telephones V is connected to ground and to the contact-plate T The contact-plate r is connected to the terminal h of the lower magnets A, and the contactplate r is connected to the terminal 7?. of the upper magnets A. The contact-plate r is joined with the hook of the receiving instrument and with the earth. Lever R stands normally between the contact-plates r and r joining them both.

In the case of only a small number of subscribers, wherein only one single selectingswitch is provided, the connection between two subscribers is reached in the manner shown in Figs. 15, 16 and 17. The selectingswiteh then used is that shown in Fig. 9, only magnet Q, the upper magnets A, B, rods C, parts G L, F and ring E being omitted, the contact 6 being fastened to the cover of the casing M.

Let it be assumed, for example, the tele phone No. 1 (Fig. 15) is to be connected,

through the scleeting-switch. (Fig. 16), to telephone No. (3 (Fig. 17). Forthispnrpose the calling subscriber No. 1 places his lover ltontaintaetplate1". The calling subscriber then rotates his cylinder. The current [lowing through the circuit thus closed causes the arm M to be rotated by the elcctro-niaguet t), in order to place the magnet. N in tront oi the magnets A 13. The circuit is as 't'ol lo\vs:trom earth 5 (Fig. to contact plate 1' contact 1. ot the key H, battery V,

. brush it, cylinder V one (it the teeth '0,

brush t, contact .9, contact. Z", lever lt, contact-plate 1", line 1, termii'ial K (Fig. '16), plate 71.", rod 1*, lower magnet A disk (1', contact (0, branch wire 3, magnet (f), to earth at 4. During the rotation of the cylinder V intermittent current impulses are, therefore, sent through the coil of the electro-magnet 0. Each current impulse causes the armature 0 to be attrzuited and the ring M to be rotated to the extent of one tooth. The upper magnets l) which constantly receive current from the local battery VII (Fig. 16) adhere to their magi'iets A by magnetic influence, as the force of the springs c is less than the magnetic attraction. The n'iagnets l3 adhere to their n'iagnets A during the current impulses sent through the latter because for one reason the strength of the current sent through the magnet B from the local battery VII is such that induction or residual magnetism causes the magnet B to resist the thrust of the spring 0, but when magnet A has no current, and because for the other reason the direction of the current of the line wire effecting the turning of M is such that it. produces in that end of the magnet A to which adheres magnet B a polarity dissimilar to that produced in the adjacent part of magnet 13 by the local. current of battery VII. Therefore to move the magnet B radially inward there must be sent through magnet A a current whose direction is opposite to that, which serves to turn arm M This reversal of the current in the line wire is produced by a stroke upon the key S. When the magnet 13 is moved radially inward the contacts 5 and Z), previously under and I), are placed under the contacts and Z). Thereby in the coil of the magnet 13 the direction of the currentis reversed,and consequently the polarity of the magnet is changed. But at the same time cessation of the depression of the key S which has to be done Very quickly causes flow of the current in the original direction and thereby the original polarity of the. magnet A is restored, so that the adjacent ends of the magnets A and 13 then have again like polarity. If the polarity of the removed magnet 13 were not changed the said magnet would be attracted again by the magnet A when the depression of the key ceases. The red C. moves inward,

with the magnet. 15 and disk 0' fixed thereto. The contact between the said disk and cl is broken, and the circut energizing the magnet is thus opened, while the magnet. A is connected with the ring .1), as the disk a touches the ring I) by repulsion ol" magnet ll. The coils ol all the other magnets A remain connected through the disks 0 and contacts (i to the wire leading to the magnet t), and all the other magnets 13 remain ad hei-ingtothemagnetsA. ()ulytheinagnetll is moved. By this means the disk 0 on the rod C is brought into contact with the contact rings 0 and 0 and thus closed, in conjunction with the brush a", the circuit containing the battery I. This circuit (Fig. 17) goes over contact-ring a, disk 0", contact ring c, brush a, magnet N, magnet J", magnet 0, back to battery I. The magnet N at tracts its armature a and moves the rod '21 into engagement with the recess a in the knob (f in line with it. The attraction of the armature a causes the corresponding lower red C to move inward, and the disk 0 on the said rod is thrust. against the ring 1*). The two telephones are thus connected to each other, since the energizing of the magnet J 2 and N causes the cylinder H to be attracted and the contact between the other rods F and plates 72. to be broken, while the rods 1* and F of which F has been moved already downward, when magnet- B is repulsed and F by excitation of magnet N, now follow the downwardly moved plates h and remain in contact tl'ierewith. In this condition the selecting switch station is disconnected. from all the telephones with the exception of No. 1 and No. 6. At the same time with magnet N the magnet- 0 included in. the circuit: of the local battery I also is excited and attracted by the fixed magnet 11* which has received current by the local battery III. Thereby the armature 0 the pivoted holding pawl 0 and the driving pawl o are moved radially inward by the forked rod 0 which turns the magnetO and releases the teeth M The weight P tends now indeed to turn back arm lVP in its initial position, but that. is prevei'ited, as aforesaid, as the excited magnet N has attracted his armature a and the core 72. has entered the hole 0 of the head The connection between. the exchange switches of telephones No. 1 and No. 6 (Figs. 15 and 17) is as follows:-from ground 5 in the already described manner over battery V to the line wire Z, thence to plate 71., rod F magnet A disk of the rod C ring E, disk 0 of the rod C", magnet A, rod F, plate h, line wire (I to terminal 0*, and through the exchange switch of telephone No. 6 over the lever B touching in its position of rest the contact plates 7 and r, to r and from there over the coil of the bell-magnet and the hook of receiver to the earth.

The called subscriber, whose attention is excited by the bell, takes oil his receiver, breaks thereby the circuit of the receiver contact plate to the bell and sets the latter in rest. Meanwhile on the calling telephone lever R is placed between T and r". The two telephones are then ready for conversation to take place, while drum V is separated from B. As aforesaid, the proper telephones are connected with the terminal 1' and the earth. Now the calling subscriber takes off his receiver and the conversationcurrent flows :ground at 5, telephone No. 1, one coil of inductor )V contact-plate '1 over the lever R to contact-plate 1' line wire Z, terminal K (Fig. 16) plate 7L rod F to the lower magnet A and the corresponding disk 0 on the core C ring E, disk 0 through the magnet A, the rod F, plate 1., over the line wire 6 to the contact plate r of telephone No. (3, over the lever B, contactplate r coil of inductor to the telephone of the called subscriber No. (S to the earth and through the latter back to telephone No. 1. The microphone N and the other coil of inductor W lie in the circuit of the battery VI which is closed when the receiver is removed from its hook. If the conversation is finished, the lever B of the calling telephone No. 1 is moved back to contactplate T and the key S is temporarily depressed. This causes current to flow tl'n'ough the magnets A and A, and the magnets B and B are attracted by the magnets A while the key is depress-ed. At the same time the circuit of the magnet N is opened owing to the removal of the disks 0 on rods C and C from the rings 0 and c and B can follow the attraction of A. The lower contact plates 5 and Z) are again placed under the plates 6 and b and the polarity of the magnets B and B is changed. The key is at the same time released, and a current is again sent through the magnets A. The adjacent ends of the magnets A and B being new of opposite polarity the magnets remain in contact with each other until the key is again quickly depressed. As the breaking of the current in magnet N renders also the magnets J 2 and 0 currentless, the slider H by the power of spring J returns in its initial position, and the weight P can turn back arm M in the initial position. The lever R of the calling telephone N0. 1 is placed between the contact-plates 7' and 0 and the subscriber who had given the call can be called up by any of the other subscribers.

For making and breaking the connection between two telephones through one single selecting-switch for purposes of conversation, the following operations are, therefore, required at the calling subscribers apparatus:-(1) Adjustment of lever R on the contact plate r of the wire leading to the lower magnet Rotation of cylinder V. (3) Short depression of the key S. (4;) Adjustment o'li lever lt between contacts 1' and 1. (5) Return of lever B to '1. (6) Short depression of the key S. (7) Adjustment oi lever it between the plates '1' and '1'.

Figs. 18 to illustrate the connection between two telephones in the case of dilierent groups of for instance 10 subscribers in each group. Let it be assumed, that for instance the subscriber No. 2 of group No. 1 (Fig. will be connected with the subscriber No. 7 of group Ill (Fig. 18). For this purpose the calling subscriber No. I2 connects at first the selecting switch (Fig. 21) belonging to his group, with the selecting switch (Fig. 20) common to all groups, joins'no'w this latter selecting-switch with that one belonging to the group of the subscriber to be called (Fig. 15)) and fits it finally on the line wire contacts oi the telephone No. 111 7 to be called 18).

For making the connection between the telephones I 2 and lII7 there has to be done in detail the following (1) Lever 1% (Fig. 22) is adjusted over contact plate 1'. The line current excites the coil A of the upper magnet pair (Fig. 21) and goes back to the earth, on the following path: earth at 12 (Fig. 22), contacts z, a battery V, brushes t, ('3 contacts 5*, -27, lever B, contact 7, line wire 2, sliding rod 7a. (Fig. 21), red F upper magnet A disk upper contact E lever G cylinder E to earth. By the excitation of A the magnet B is repulsed and draws with it the disk Q. Thereby, in the same manner magnet N in the example given hereinbefore, magnet Q is inserted and thereby the selecting switch (Fig. 21) is connected with the one (Fig. 20) common to all groups. The current of magnet Q flows from battery II over ring Q disk ring to coil Q and from there back to battery II. The connection with the central selecting switch (Fig. 20) takes place through the following circuit: from the earth at I2 (Fig. 22) in the manner hereinbefore described to the upper magnet A to the corresponding disk c adhering at ring E b repulsion of B ring E to the disk 0 of the core Q of magnet Q, through the magnet A of this core, rod F sliding rod h over line wire 1 to sliding rod ]t1 of the selectingswitch (Fig. 20), rod F magnet O to earth. By excitation of the upper magnets A and A (Fig. 21) the adhering magnets B and B are repulsed, the contact between I) and b is broken and the lower magnets B and B receive no currrent. Therefore they will be repulsed from their magnets A and A by the spring 0. By this repulsion contact is made between 0 c 0 magnet J 2 is eX cited and the cylinder I-I moves downward,

where the rods F and F are already pushed so that the conversation circuit oil the lower magnets A is completed. ()n the central selecting switch (Fig. 20) the upper maget li is repulsed also l'rom its magnet. A by excitation but the lower magnet B will not he re pulsed thereby, because it still receives cur rent as the sliding contacts are suitably arranged for this purpose.

(Z) The drum V ot the calling telephone is turned three times. The current impulses sent thereby to the central selecting switch (Fig. 20) in the described manner move arm M opposite the core rod (23) ()n the calling telephone No. I (Fig. L2) the lever It is adjusted over the plate 9* and the key S is then momentarily depressed. lherc is thereby sent a current of opposite direction to the lower magnets A of the selecting switches (Figs. 21 and. 20) through the following .:ircuit:--tl"rom the ground at .l--2 (Fig. 22 )to contact 7", over the path. as hereinbe'liore described, through I this subscribers apparatus to contact r and the line wire 2', to .0 F (Fig. 2i), lower magnet A disk 0, ring R, to disk 0 of lower magnet A, A", F in, line wire I to the central selecting switch (Fig. 20), there over 71/ F to the lower magnet A disk 0 core C cylinder E to earth. By this current the armature of the lower magnot B (Fig. 20) is repulsed and disconnected from the local battery VII. At the same time by the contact 0 a, 0 the electromagnets N, J and 0 are connected to the local battery II of the central selecting switch (Fig. Thereby the following circuit to the selecting switch (Fig. 19) of the group of the subscriber No. III-7 to be called is completed :-by the circuit already described from telephone No. I2 (Fig. 22) over the lower magnets A and A (Fig. 21), to the lower magnet A, (Fig. 20), winding E of the lower magnet A F h line wire for station III, M F (Fig. 19), lower magnet A disk 0 contact (Z, magnet O to earth.

(4) Drum V of the calling subscriber is turned seven times and the key S is de pressed. Now the telephones in question are connected. By turning the drumV 7 times the arm M is actuated by the current impulses passing through the magnet O and brings the magnet N to its operative position relative to the contacts and the magnets A B of the called subscriber. By depression of key S and the current impulse of opposite direction produced thereby the lower magnet 13 (Fig. 19) is repulsed, contact 0 c c is closed, magnet N excited and magnet B also repulsed. Now from telephone No. I--2 to telephone N0. III7 the following circuit is completed :-earth at I2 (Fig. 22) contacts 1' t, 8', battery V, contacts 6, t 8, t lex er R, contact r line Wire 2, to the selecl ing switch (Fig. El /t'-" F lower magnet .V, ring I), lower magnet A", l ,/t", line wire I central SultftitlllSWlttIll Fi .40 /i., F I 7 a; w h a a rower magnet A rmg lb, lower magnet A l h line wire 'l'or station III to selecting switch (Fig. la), h F loyrewrnag net A t, r ng 1:, lower magnet It, l M, line wlre i to teleihone ho. .lllf t coni 7 I 7 tucts rr bell hook ott rccerver to "round.

h a (a) litter inns-hing the (amrersatum the lever [C of the calling tele )hone is moved to contact-plate r, and the key H is then dcpressed. in all three selecting switches the upper magnets ll more back to the respective magnets A.

((3) Lever 1% is moved to contact-plate '1' and the key ti is then depressed. In all three selecting-switchcs ll e lower magnets .li more back to the respective magnets A.

(7) At last the calling subscriber moves his lerer it between contacts w and r and thereby the position olf' rest is restored.

What I claim as my invention and desire to secure by Letters Patent ol' the United States 1.. In an automatic telephone system, the combination of a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus, comprising a talking con tact and a series of rods, means operated by said line circuit for moving the rod corresponding to the calling telephone to, and off said talking contact, a local. circuit, means for closing said local circuit, a motor operated by said line circuit, an arm moved, by said motor, an electro-magnet carried by said arm and lnmught to the rod correspond ing to the tclepnone ot the called subscriber, said electro-magnet being excited by said local circuit for moving the last named rod to said talking contact. and means tor rcturning the parts to their initial. position.

In an automatic telephone system the combination of a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus comprising a central placed talking contact and a series of rods arranged radially to the said contact, means operated by said line circuit for moving the rod corresponding to the callers telephone to said contact, a local circuit. closed by the moved red, a motor con'iprising an electromagnet excited by said line circuit, an arm moved by said motor circularly about the selecting switch :-i ipa1'atus, an electro-mag net carried by said arm and brought. to the rod corresponding to the telephone of the called subscriber, said electro-magnct being excited by said local circuit for nmring said rod to said talking contact, and means for returning the parts in their initial osi.tion.

3. In an automatic telephone system the combination of a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus comprising a talking contact and a series ol. rods, means operated by said lino circuit for i'noving the rod corresponding to the callers telephone to said contact, a pair of elcctro-niagnets on each ol. said rods, for operating said means and tor removing said rod, one of said electromagnets being stationary and inclosed in said line circuit while the other is movable with the rod, a local circuit in which the mm ed clectro-nnignet is included, connections for reversing the polarity of the movable mag net, another local circuit closed by the moved rod, a motor operated by said line circuit, an arm moved by said motor, an electromagnet carried by said arm and adapted to be brought to the rod corresponding to the telephone of the called suliiseriber, said electro-magnet being excited by said other 10- cal-circuit for moving said rod to said talking contact, and means to return said arm in its initial position on breaking of said other local circuit by removing the rod con responding to the callers telephone by the operation of the line circuit.

4. In an. automatic telephone system the combination of a plurality of telephones, a line circuit for each telephone, a -nleeting switch apparatus, comprising a talking contact and a series of rods, means for moving the rod corresponding to the callers telephone to said contact, a fixed magnet surrounding each rod and included in. said line circuit, a magnet movably disposed on each rod, a local circuit in which the moved electro-magnet is included, means for reversing the current in said fixed electromagnet to produce repulsion of said movable electromagnetand to restore the polarity of said fixed electro-magnet, connections between said local circuit and said movable electro-magnet for reversing its polarity, a second local circuit, closed by the moved rod, a motor operated by said line circuit, an arm moved by said motor, an electromagnetcarried by said arm and adapted to be brought to the rod corresponding to the telephone of the called subscriber, said electro-magnet being excited by said second local-circuit for moving said rod to said talking contact, and means to return said arm in its initial position on breaking of said other local circuit by removing the rod corresponding to the callers telephone by the operation of the line circuit.

5. In an automatic telephone system the combination of a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus comprising a talking contact and a series of movable rods, two electro-magnets on each rod for controlling its movement, one of said magnets being fixed on the rod whereon it is mounted and the other slidable on said rod, a spring for moving the rod corresponding to the callers telephone to said contact, the strength of the spring being less than the force of at traction due to excitation of both electromagnets when the latter are apart, and less than the force of attractioi'i due to excitation of the one electro-magnet alonewhen it is in contact with the other magnet, but greater than the force of attraction due to excitation of one of the magnets when the latter are apart.

(5. in an automatic telephone system the coi'nbinatiou ot a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus, comprising a talking contact and a series of rods, means operated by said line circuit for moving the rod corresponding to the callers telephone to said contact, means for restoring said rod to its initial position, a local circuit closed by the moved rod, means operated by said local circuit for moving the rod corresponding to the telephone ot the called subscriber to said talking contact, an electro-magnet included in said local circuit, a second contact connccted in its position of rest with all of said rods and operated by said electro-magnet to break the connections with the remaining rods when two of said rods are moved.

In an automatic telephone system the combination of a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus comprising a talking-com tact and a series of rods, means operated by said line 'circuit for moving the rod of the callers telephone to and from said contact, a. local circuit closed by the moved rod, a motor comprising an electro-magnet operated by said line circuit, an arm moved by said motor, an electro-magnet included in said local circuit carried by said arm and adapted to be brought to the rod of the called telephone for moving this rod to said talkii'lg contact, means for returning said arm to its initial position on breaking of the said local circuit by removing the rod corresponding to the callers telephone, a pawl releasably preventing the removing of said arm, and an elect-ro-magnet included in said local circuit to releasesaid pawl when energized.

8. In an automatic telephone system, the combination of a plurality of telephones, a line circuit for each telephone, a selecting switch apparatus comprising a talking-contact and a series of rods, means operated by said line circuit for moving the rod of the callers telephone to and from said contact, local circuit closed by the moved rod, a motor comprising an electro-magnet operated by said line circuit, an arm moved by said motor, an electro-magnet included in said local circuit and carried by said arm and adapted to be brought to the rod of the called telephone for moving this rod to said talking contact, means for returnlng sald arm to its inltial position on breaking of the said local circuit by removing the rod corresponding to the callers telephone, a toothed ring on said arm, a pawl connected with said motor and engaging said toothed ring for moving said arm in one direction and holding the arm when moved, a movable electro-magnet connected to said pawl and included in a proper local circuit, a fixed electro-magnet in the local circuit, closed by the callers rod, said movable electro-magnet being arranged to release said pawl from the toothed ring, and contacts in the first mentioned local circuit adapted to be broken by return of the arm.

9. In an automatic telephone system the combination of a plurality of telephones forming groups, a selecting switch apparatus, serving as subcentral station to each group and connected by a line circuit with each telephone of its group, a selecting switch apparatus serving as central station to all selecting switch subcentral stations and connected with each of them, a line circuit, each selecting switch apparatus being provided with a pair of contacts, two series of rods, a fixed and a movable magnet on each rod, means formoving the two rods corresponding to the callers telephone and to that of the subscriber to be called to thereby close said contacts, and means for returning all of the parts to their initial positions.

10. In an automatic telephone system, the combination of a plurality of telephones forming groups, a selecting switch apparatus serving as subcentral station to each grou and connected by a line circuit with each telephone of its group, a selecting switch apparatus serving as central station to all selecting switch subcentral stations and connected with each of them by a line circuit, each selecting switch apparatus including a pair of contacts, two series of rods, there being a pair of rods for each telephone, means for operating said rods, means for re turning all parts to their initial positions,

each rod being provided with one fixed and one movable electro-magnet, the two fixed electromagnets of each pair of rods being included in the line circuit of the corresponding telephone, one of the two movable clectro-magnets of each pair being included in a local circuit and both movable electromagnets being provided on their adjacent parts with contacts which change their relative position when said electromagnets are displaced with their rods, said contacts being arranged to close the local circuit through the remaining movable magnet, said circuit being closed at a predetermined point in the movement of the first movable magnet and open at all other points. v

11. In an automatic telephone system the combination of a plurality of telephones, a selecting switch apparatus serving as subcentral station to each group, a receiving switch apparatus serving as central station to all selecting switch subcentral stations, each selecting switch apparatus including two contacts, two series of rods, means for operating said rods, and means for returning all parts to their initial position, a local circuit having contacts, the one series of rods of the selecting switch subcentral stations being provided with means for closing the circuit through an electromagnet excited by said local circuit and thereby operating the central selecting switch station, to make the connection with the selecting subcentral station of the group to which belongs the telephone of the subscriber to be called and to operate thereby this subcentral station to make the connection with the called telephone.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

VALERIAN ALEXEEFF.

Witnesses:

WLADIMIR RADOWSKY, LUSBURG RASOHINSKI.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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