USRE16086E - Nongrounded or metallic line-circuit system - Google Patents

Description

May 26, 1925.

R. H. BURFEIND NONGROUNDED OR METALLIC LINE CIRCUIT SYSTEM Original ile April'ls, 1907 5 Shests$heet l t1usnImr f B mcmU'HBurTE'z cf May 26, 1925.

Re. 16,086 R. H. BURFEIND NON-GROUNDED 0R METALLIC LINE CIRCUIT SYSTEM 3 Sheets-Sheet 2 Original Filed April 18, 1907 Jnueniur R. H. 'B RFEIND NON-GROUNDED OR METALLIC LINE CIRCUIT SYSTEM Original Filed April 18, 190? 3 Sheets-Sheet 3 Reissued May 26 1925.

UNITED I STATES mmoma H. num'nmn, or cmcaoo, rumors, asslsnoa, BY misun- ASSIGNMENTS,

TO AUTOMATIC ELECTRIC COMPANY, A CORPORATION OF ILLINOIS.

NONGBOUNDED OB METALLIC LINE-CIRCUIT SYSTEM.

Original in. 1,299,119, dated April 1, 1919,8612 no. 369,021, med April 18,1907. Application for reissue fled August 80, 1920. Serial No. 407,038.

To all whom it may concern:

Be it known that I, RAYMOND H- BUR- FEIND, a citizen of the United States of America, and resident of Chicago, Cook County, Illinois, have invented a certain new and useful Improvement 3 in Nongrounded or Metallic Line-Circuit Systems, of which thefollowing is a specification.

Myinvention relates to automatic telephone systems in which means are provided for enabling a' calling subscriber to extend his line into connection with the line of the called subscriber, or into connection with some other, line, without the aid of operators. 1 v

The principal object of my invention is therovision of an improved system in which the apparatus at the exchange or central station may" be controlled by the callin subscribers, for the purpose of establis ing connection with the lines of the called subscriber, or for the purpose of disconnecting a'nd restorin the automatic switches after the subscribers are through talking, without employing operating without employing ground circuits between the substations and thecentral station.

It is also an object, of course, to provide certain details .and features of im prover'nent and combinations tending to increase the general elficiency and serviceability of an automatic tele hone exchange system ofthis particular c aracter.- v

- In application No. 369,013, filedApril 18, 1907, by A. E. Keith for improvement in non-grounded or metallic circuit systems,a system is shownin which the switches are operable, without the necessity of using ground connections at the-subscribers stations. Also, in application Serial No. 369-,-

-012, filed April 18, 1907, by E. AQMellinger,

a system is shown in which a plurality of automatic switches are successively controllable or operable .without using 'grounds at the substations, and these switches are also releasable; in the same manner. My

present invention is, therefore,'- in the nature of an improvement on the s stems thus disclosed in t lin r applications. v

w n the accompanying drawings, Figures 1 and 2 taken together represent diagramt the substations-that is to say,-

e said prior Keit and Melmatically a calling substation A connected by means of central oflice switching apparatus with a called substation A, in a systemembodying the principles of my invention. The switches, through which the stations A and A are shown connected, comprise, in Fig. 1, the so-called first-selector C and second-selector D; and in Fig. 2,.

a connector E and a first selector C similar to the first-selector C. The selector C is individual to the line of the substation A, while the first-selector C is individual to the line'nof the substation A, #2220.

The said selectors Q and C are substantially thezsame in construction. For 'opcrating the central ofiice switches there is provided a central source of current or'bat ter B having its positive terminal prefera lygrounded at G (Fig. 2).

Figs. 3, 4 and 5 are detail views of the I substation impulse springs.

Figs. 6, 7 and 8 are detail views ofv the release relays of the selector and connector switches. 1 4

It will be understood, of course, that in thls'system the first-selectors are arranged in groups, as wellas the second-selectors and theconnectors. -A somewhat common arrangement is to divide the substations.

into groups of one hundred, and to, of course, 'dividetheir' allotted selectors into corresponding groups. Furthermore, every groupof. first-selectors has allotted to it a group of second-selectors for every-bank level. Through the medium of the second- -selectors the connectors of various hu-ndred-groups are reached. The connectors and second-selectors are less in number than the subscribers-that is, they are" employed ,on 'a' percentage basis. The substation may be of any suitable or approved type. elected to illustrate my invention comprises 7 The one in connection with which I have a receiver 2, switch-hook 3 for controlling the substation circuits, which controlling dperationsare accomplished through the medium of any suitable means, such as the cam-arms 4: and 5; ,When the switch-hook is down, thecam-arm 4 carries the s ring 6 out of engagement with the spring V and into engagementwith the spring 8, thereby bridging the ringer 9 in series with the condensers 10 and 10' across the line; Furtherand rotary impulse springs 18 and 19. Said substation is, of course, rovided with a dial, which is not shown ut which is securedto the shaft 20, together with the locking dog 21. Furthermore, there is a. locking cam 22 that locks the dog 21, while v the receiver is on the switch-hook, to prevent a rotation of the dial. For operating the impulse springs18 and 19 (Fig. 3) the substation is provided with an im ulse wheel 23 that is secured to the sha' 20,

' which impulse wheel carries on its periphery'the so-called ertical impulse eeth 24 and one rotary impulse tooth 25. .c said impulse teeth are so arranged that when the dial is drawn down the impulse springs 18 and 19 are not operated; but as the dial returns, first the vertical teeth engage the vvertical im ulse spring 18 (Fig. 4) and after they have completed their work the rotary impulse tooth 25 operates the rotary impulse spring 19 (Fig. 5). In this operation the vertical impulse spring 18 is pressed into contact with the spring 26, whereby the vertical line conductor 27 becomes connected directly withthe rotary line conductor 28 Normally, when the receiver is re moved, the vertical and rota line conductors 27 and 28 are connect through the high resistance coil 29. After the vertical impulse teeth have operated the vertical impulse sprin 18, the rotary impulse tooth 25 momentari y disengages the springs 19 and 30, whereby the line conductors 27 and 28 become separated; and when the springs engage, the line conductors 27 and 28 are again connected through the coil 29. It will be clear from the drawings that when the subscriber rotates the dial the rotary impulse tooth 25, upon returning or rotating in a counter-clockwise direction, meets the angled member shown on the end of the spring 19, pressing, as it advances, both springs 19 and 30 out of the way, but without breaking connection. However, when the dial returns toward normal position the rotary impulse tooth 25 comes in behind the member on the end of the spring 19, flexing the said spring 19 away from the spring 30, thus breaking the circuit as de, scribed. It will be understood, furthermore, that the shaft 20 is provided with a sprin adapted to restore the dial when once it as been rotated out of normal position. Furthermore, the switch hook also provided with any suitable whereby said switch hook may be caused to rise when the weight of the receiver 2 is prises the push button 31, which, when pressed, carries the spring 32 into engagement with the contact point 33, whereby the line conductors 27 and 28 are connected.

The first-selector switch shown at C maybe of any suitable or approved type, for instance of the general type described in United States Patent-No. 815,321, granted March 13, 1906, to Keith, Erickson & Erickson. Among other details, it embodies the following well-known devices and circuits: The switch shaft 34 carries the vertical and rotary wipers .35 and 36, respectively, and. the private wiper 37. The side switch is well known and comprises the side switch wipers 38, 39, 40, 41. and 42, which may be designated as the vertical, rotary and pri vate side switch wipers, the rotary magnet wiper and release relay wiper, respectively. The side switch is under the control of the private magnet 43, and when the side switch is in normal or first position the wipers 38, 39, 40, 41 and 42 occupy the contact points 44, 45, 46, 47 and 48, respectively. In the second position they rest on the contact points 49, 50, 51, 52 and 53, respectively, and in third position the contact points 54, 55, 56, 57 and 58 are engaged by their respective wipers. Through the medium of the vertical line relay 59, and while the side switch is in first position, the subscriber controls the vertical magnet 60, which latter operates to raise the switch shaft 34 and wipers 35, 36 and 37 'verticall By means of the rotary line relay 61, an before the shaft has rotated to disengage the springs 62 and 63, the subscriber controls the private magnet 43, and, therefore, the side switch. While the side switch is in. second position the rotary magnet 57*, which operates to carry the switch shaft and wipers 35, 36 and 37 in a rotary direction, is energized. The relay 63 provides the means whereby the subscriber controls the release magnet 64 while the side switch is in the -first or second position, and while the switch lUI) gagement with the spring 143 and into engagement withthe spring 32 thelatch 31 then falls over the end of the spring 32 and locks the two springs 32 and 142 in contact (Fig. 7 'Now, when the relay 63 deenergizes, the two locked springs 32* and 142 are carried into engagement with the spring 143; then when the release magnet 64 energizes, the armature 33 is attracted and re the hitch Si in such that it turns about its pivot oints on the end of the spring 142 and un ocks the springs 142 and 32, whereby the two springs disengage. If the side switch passes to the third position, then since the selector C is of the trunkrelease type, the selector through the next switch, and a connection with the latter is thenestablished through the private wiper 37 and by .means of the back-release rela 65. The bridge-cut-ofi relay 66 is provi ed to open the connection between the line relays 59 and 61 and the battery terminals. It will be noticed that the vertical line relay 59 is connected to the non-grounded terminal, and that the rotary line relay 61 is connected to ground. This disconnection is desirable, because if the relays are not disconnected from battery, the ringing current for signaling the subscriber may then operate either or both of the relays 59 and 61 and cause some interference with the switch. It is also desirable to remove the ridge formed through the said relays from across the line so as to give the voice-currents as clear a path as possible. Furthermore, the shaft 34is provided with the cam 66 which, when the shaft is in normal position, permits the springs 62 and 63 to disengage; but on the first vertical step of the shaft 34 the cam 66 presses the said springs into engagement. a. Now when the shaft is given a rotary step the cam 66 is carried out of engagement with the spring 63, and the springs 62 and 63 disengage. The switch-shaft is provided with a normal arm 67 which, when the shaft is given a vertical im ulse, permits the spring 70, which normal y engages.

the spring 68, to pass into contactwith the spring 71. v

The second selector D is similar to the first selector C, with the exception that there are no normal conductors, such as the normal conductors 72 and 73. Since there is no use for such conductors they are omitted. There is also no utility in the second selector for a bridge cut o-fi relay, such as the relay 66 of theselector C, and this is also omitted, and the line relays are connecteddirectlyto the battery terminals. The private normal conductorfsuch as the private normal conductor 74 of the selector G, is of no use in connection with the second selector and is also omitted. Since likeparts are similarly represented throughout the drawings, the vertical magnet 75 and the rotary magnet '76, the release magnet 77 and the private magnet 78 will be recognized and understood. The said private magnet 78, of

course, controls the side switch wipers 79, 80, 81, 82 and 83. The vertical movement of the switch shaft 84 and, therefore, of the wipers 85, 86 and 87, is controlled by,the vertical magnet 75, and the rotary movement by the rotary magnet 7 6, the'rotary magnet is controlledv shaft wipers their vertic circuit being provided with the usualfinterrupter springs 88. The operative magnets of the switch are, of course, controlled by the subscriber through the medium of the vertical and rotary llne relays 89 and 90, as is well known. Said relays have under their control the usual springs 91, 92 and 93. The

selector D is also provided with a release relay 94 for controlling the release of the switch when the side switch passes to third position. The relay 95 controls the ener '2- ing circuit of the release magnet 77' w 'le the side switch is in first and second posi tions and the shaft is 011' normal. The release controlling relay 95 in the secondselector operates inlthe same'manner as the release relay 63 of the first-selector. If,

while the said switch of the selectorl) is in and moves the latch insuch manner that it turns about its pivot points on the end of the spring 99 and unlocks the and 102, whereby the two springs sengage. The cam springs 96 and 97 are" controlled by the shaft cam 98, in the same manner in which the cam springs of the selector controlled.

C are springs 99 The connector switch E may also of} any suitable or approved type, for instance of the general type described in United States Patent No. 815,17 6, granted March. a

13, 1906, to Keith, Erickson & Erickson. The mechanical details of the first-selector and connector, as is well known, are vei much the same. The connector switch sha t 104, like the first-selector switch shaft, car-.

ries the line wipers and 106 and the private wiper 107. The connector switch is also controlled b the calling subscriber through the medium of the vertical and rotary line rela s 108 and 109. The vertical line relay directly controls the vertical magnet 110, and also the rotary magnet 111 and the ringer relay 112. The ofiice of the vertical magnet 110 is to give the shaft and a motion, and the rotary magnet 111 imparts to the shaft and shaft wipers a rotary or circular motion. The rotary line relay 109 controls the energizing circuit of the release relay 113. The release relay 113 is similar to the relay 95 of'the second-selector, and when the relay 113 is energized the spring 129 is shifted out of engagement with the spring 130 and into the locked springs 129 and Y131 are carried into contact with the spring 130; but as the armature 133 nears its normal position, the

latch 132 comes into contact with the beveled member 134, whereby the latch 132 grad ually slides from the end of'the spring 131; and when-the said spring is unlocked it returns'to normalposition, outof engagement with the spring 129. The private magnet 114 is controlled by. the vertical line relay 108, and under certain conditions controls the release magnet 120 and also the side switch wipers 115, 116, 117,118 and'119. The side switch of the connector, like the side switch of the first-selector, has a normal or first position, a second position and a third position. The release magnet 120 is also controlled by the relay 121. By the condensers122 and 123 the circuit through I the connector is divided into 'two' sections.

The central ofiice is equipped with busy-\ signaling apparatus of any suitable desi n,

as, for example, the one comprising an 1nterrupter122' in series with the primary winding 123 of the induction-coil 124, whereby a busy-signaling current is induced in the secondary winding '125 of the said coil. The connector switch shaft 104 also carries a normal t arm 126 which, when the connector shailz is oif normal, allows the sprin 127 to engage the contact point 128, wheriiy the busy-signal may be transmitted to the rotary line conductor. V

The substation A is like the substation A; also, the first-selector switch C allotted to the line #2220 is like the first-selector C allottedto the line #5000.

A clearer understanding of my improved stem ma be had from an ex lanation of t e operatlon of the central 0 ce switches when one subscriber calls another. Suppose, for an example, that the subscriber at substation A desires to communicate with the subscriber at substation A on the line #2220. The operation of the central oflice switches, to bring about this connection, is

soon as the sad springs 62 and 63 come into as follows: When the subscriber at substation A removes the receiver 2.'from the switch-hook 3 the cam-arm 4 permits. the

springs 7 and 6 to engage, whereby a series circuit including the vertical line rela 59 of the selector C, resistance-coil 29 o the substation A, and the rotary line relay 61 of the selector C is closed, This circuit extends from ground G at the selector C through the sprin through the resistance-coil 29 to the vertical line conductor 27, side switch wiper 38, con- 135 and 136, through. i the rotary line re ay 61, contact point 45,

side switch wiper 39, rotary line conductor 68 137 and 138 to the battery lead 139, thence through battery B and to ground G. The rotary line relay 61 is so adjusted that the current-flow is sufficient to operatively energize the said relay, while the vertical line relay 59 is so adjusted that the current-flow in this circuit is not suflicie'nt to operatively energize it. The rotary line relay, upon energizing, places the springs 140 and 141 in contact.- This closes a circuit through the release controlling relay 63. The C11- cuit through the release controlling relay extends from 1.41 and 140, t rough therelay 63 to the battery lead l39,'thence through battery B and to ground G. This'relay, upon energizing, separates the springs 142 and 143, and places the spring 142 in contactxwith the spring 32*. When the dial is rotated for the first digit 2 the spring 18 is twice pressed into contact with the spring 26. By this opera- .tion the line conductors '27 and 28 are diwhich does not include the resistance-coil 29, is established through the vertical and thus a new circuit,

round Gr through the springs I rotaig line relays 59 and 61 of the selector C. u

flicient current now flows in the circuit to operatively energize the vertical line relay 59, which latter, upon energizing, presses the springs 144 and 141 into contact, which closes an energizing circuit through the vertical ma net 60. This circuit extends from ground 2 through the springs 141 and 144, through the vertical magnet 60-to the battery lead 139, thence through battery B and to ground being twice pressed into contact for the first digit, the vertical line relay 59 is twice oper- G. The springs 18 and 26 atlvelyenergized, and th'evertical magnet is in turn energized twice. By this operation of the vertical magnet the shaft 34 and the shaft wipers 35, 36 and 37 are raised two-steps and brought opposite the second bank level. It should be borne in'mind that at the'first vertical step of the switch shaft the cam 66 operates to ,closein contact the normally open shaft springs 62 and 63. As

contact an energizing circuit is established through the private magnet '43 from ground G at the selector C, through the springs 141 and 140, through the cam springs 62 and 63 to the private magnet 43, thence through said magnet to the battery lead 139, and through battery-B to ground G. Furthers more, atthe. same first vertical step the normal post 'arm 67 disengages from the spring 70, permitting the latter to leave" the spring and toengage with 71. This operation, of course, disconnects the grounded spring the private normalconductor 74 from the ,7

bridge-cut-ofi relay 66 and places a guarding potential 'on said private normal con- .the second level'wi ground, as is usually the custom in systems- 7 tion, thus causes private magnet ductor from ground Gr to prevent any calling subscriber from calling in upon theline #5000 after the switch C has been operated. The rotary impulse tooth 25 separates the springs 19 and 30, which open the circuit includingthe vertical and rotary line relays and resistance-coil 29. The-rotary line relay 61, being deprived of its energizing current, de-energizes and permits the springs 141 and 140 to separate, whereby the energizing circuit of the private magnet 43 is broken,

.and the side switch is permitted to pass to second position. As soon as the impulse springs 19, an 30 again come into contact, and again the energizing circuit through the rotary line relay is established. In the meantime, however, the circuit through the release controlling relay 63 is broken, but the relay being a slow-actingrelay sufiicient residual magnetismis retained in the core to maintain the relay man operatedposltion until this energizing circuit is again established, when the rotary line relay energizes.

When the side switch passes to second position an energizing circuit .isestablished cuit' extends from the grounded" contact point 52 through the side switch wiper 41, interrupter springs 145, rotary magnet 57 to the battery lead 139, thence through battactsof the second level: but if the first trunk lineis busy some other selector (similar to the selector C) in the exchange will be resting in engagement vwith said trunk line, and the first rivate bank contact of H be found connected: to

of this general character. Therefore, when the selector shaft is rotated one ste an energizing circuit is established throng the pnvate magnet 43, when the. private wiper 37 I strikes thegrounded private bank contact,

thereby retaining the side switch in second position and maintaining the energizing (S1I'-' cult through the rotary 'magnetfl57'. The rotary magnet, by. intermittent magnetizathe shaft to rotate step by step and carry the private wipers past the last busy trunk line. However, as soon as the private magnet is deenergized the side i a p switch is tripped into third position; but.

if there are no busy contacts to be passed over, as assumed in the firstinstance, the 43 .trips the side switch to v tact points.

trunk through the rotary magnet,,57. This cir-' being energized, the shaft wipers 35, 36 and 37 are carried selector leads ofi from the first set of con-- to the battery lea third position, with the result that the side switch wipers engage their respective con- 38 and 39wpass to third 7 osition the subscribers lineconductors 2 and 28 are extended to the conductors leading to the selector switch D; also, since the side switch wiper 40 engages a grounded contact point 56, a guarding potential is established at the private wiper 37 for protecting the seized line from being molested by any other switch. It will be noticed that after the side switch passes to third position the relay tooth 25' disen ages from the spring 19, the

63deenergizes, and the springs 32 and 142 engage with the spring 143, but the engagement of the said. springs at this particular time is without efiect, since the side switch wiper 42 has passed to third position'and engaged the idle contact point 58; Furthermore, when the shaft 34 is given the first rotary ste the cam 66 passes out of engagement wit springs 62 and 63 to disengage. This 'disengagement breaks the, energizing circuit formed by therotary line relay throughthe private magnet 43 and leaves the control of the latter to the guarding potential (when the side switch wiper 4O isin second osition) on the private bank contacts w ich areengaged by the private wiper 37. The second di it is called after the subscriber has established connection with the selector D7by way of the trunk conductors 146 and 14 Y 'When the are seized an energizing circuit is established through the vertical and rotary line relays- 89 and 90 of the selector D, in the same manner in which the circuit was established through the vertical and rotary line relays of the selector C. The rotary line relay energizing circuit through the release relay 95. The circuitthrough the release relay extends from ground G through the springs 91 and93, through the rela. 95 to thebatterylead 139, thence through attery B and. to ground G. The relay, 9'5 energizes and locks the springs 99 and-102 in contact, as explained. The subscriber rotates thev dial, as described, for the second digit 2, thereby shuntingo'r short-circuiting the resistance-coil 29 when the sprin 18 and 26 engage. The vertical line re 9g! 89 now operatively energizes and places e springs trunk conductors146 and 147 When the side switch wipers the spring 63 and. permits-the.

90 energizes and closes an 91 and 92 in contact, whereby a circuit 18' closed through the vertical magnet 75, said circuit/extending from and G through the springs 91 and 92 t tough the magn et.

d 139, ones through battery B and to ground that the vertical magnet 'is enerfgized operates to raise the s aft one step at a. time until the said wipers are carried two steps and brought opposite- G. Each time 3 and sha wipers the level in which are located the terminals of the-trunk conductors 151 and 152 leading to the connector switch E. In the man- I ner described in connection with the selector C when the switch shaft 84 of the selector D moves up the first step, the cam 98 presses the cam springs 96 and 97 into contact, whereby an energizing circuit is set to second position,

up through the private magnet 78. This energizing circuit extends from ground G through the line relay springs 91 and 93,

through the cam springs 96 and 97 to the private magnet 78, thence to the batterylead-139, and through battery B to groundv G. When the rotary impulse tooth separates the springs 19 and 30 the energizing circuit through the rotary line relay is interrupted, and the said relay restores the springs 91 and 93 to normal position, which breaks the energizing circuit through the private magnet 78 and the release relay 95. The rivate magnet, upon deenergizing, permits the side switch to pass from first being slow-acting, however, the rotary impulse tooth 25 disengages from the spring 19, and the energizing circuit of the rotary line relay is again established, and the' s rin 93 and 91 again engage, closing the ci rcuigz through the release relay before the armature of said relay has time to fall back. When the side switch wiper 81 engages the, grounded contact point 148 an energizing circuit is established throughthe rotary magnet '76. This circuit extends from the grounded contact point 148 A through the side switch wiper 81, interrupter springs 88, rotary magnet 76 to the battery lead 139, thence through battery B to ground G. The rotary magnet, by intermittent 'energization, operates to rotatethe. shaft and shaft wipers step' by step and carry the wipers past the last busy trunk line, if any such are found, as described in connection with selector 0. When the wiper the side switch passes to third position, thus extending the subscribers line'conductors 27 and 28 to the conductors 151 and 152 which lead to the connector switch E. Also,

- since the side switch wiper 82 engages the grounded contact point 153, a guarding potential is established at the privatewiper 87 for protecting the seizedtrunk line from Z being molested by any other switch. Of

course, when the side switch passes to third position and the energizing circuit is broken through the line relays 89 and, 90, the @1 91- The release relay 95 gizing circuit is, as a result, also broken through the release relay 95, which relay then permits the springs 102, 99 and 101 to come into contact. The coming into contact of these springs when the'side switch is in third the si e switch wiper 83 maintains the release circuit open at the time. Since the subscribers line conductors 27 and 28 are now extended to the connector E, a circuit is established throu h the vertical line relay 108, resistance re ay 29 at the substation A, rotary line relay 109 of the connector E. It will be noticed that in each instance when the subscribers vertical and rotary line conductors 27 and 28 are extended to the next switch a new energizing circuit is established through the line relays of the new switch and through the substation re-- sistance coil 29. At the same time, of course, the old energizing circuit through the line relays of the preceding switch is broken. The subscriber ing rela'I 113. This circuit extends from ground through the springs 154 and 155, through the winding of the relay 113 to the battery lead 139, thence through battery I rent for energizingjthe vertical linerelay flows from 'ground through the rotary line ,relay 1091 0 the'trunk'conductor 152,

shaft wiperj86,'side switch Wiper 80,-conductor 147 shaft wiper:36, rotary conductor 28, springs 26vand 18 to thevertical line con,- ductor 27, side switch wiper 38, shaft wip7er 35, conductor 146, side switchjwiper shaft wiper'85; conductor 151w the vertical line relay 108, thence to the battery lead 139, and through battery B to ground G Each time that the vertical line. relay is energized the line relay springs 156 and 154 are pressed into contact, thereby closing an energizing circuit through the vertical magnet also, the spring 157 is pressed into contact'with the ground spring 154, where-I by the energizing circuit is established through the private magnet 114, The circuit through the vertical magnet extends from ground G through the springs 154 and 156, side switch wiper 117, through the vertical magnet 110 to the battery lead 139, thence through battery B and to ground a G. Each time that the vertical magnet is energized itoperates to raise 'the shaft and shaft wipers one step at a time until the osltion is of no consequence, sinces conductors'27 and, 28 having been extended to the connector E thevv rotary line relay 109 operates and places the springs 154 and 155 in contact, which closes a circuit through the releassaid wipers. are carried up two steps and brought opposite the level in which are located the terminal contacts of the line #2220. The circuit through the private magnet 114 extends from ground G through the springs 154 and 157 to the side switch wiper 118, through the private magnet 114 to the battery lead 139 thence through battery B and to ground The private magnet, upon energizing, closes the springs 158 and 159 in contact, thereby closing a circuit which locks the private mag-' net in'an operated position. This locking circuit extends from ground G throu h the springs 154 and 155, 'springs 158 an 159, through the winding of the private ma net 114 to the batter lead 139, and throug battery B to ground G. When the rotary line relay 109 deenergizes, due to the rotary impulse, the locking circuit through the private magnet 114 is broken. The private magnet'now deenergizes and permits the i side switch to pass to second position, thus I placingthe side switch wipers 115, 116, 117,

118'and 119gin connection with their respectivecontact points in second position. Dur- 0 nauIgjht' the, subscriber energizes the vertiing the' time in which the rotary-relay 109 is deenergized the releasing relay 113 is maintained in its operated position b the residual magnetism. The last digit eing cal ne relay-108 ten times and deenergizes 'the rojtaryline relay 109 once. However,

' whenfthe line relay springs 156and 154 engage, a circuit is thereby closed through the rotary magnet-111 instead of through the vertical magnet 110. The energizing circuitextends from ground G through the springs 154 and 156, side switchwiper 117' 40: p

' tery lead 139, and through. battery B to .to the rotary magnet 111, thence to the batground G. Each. time that the rotary magnet is energized it rotates the shaftan'd shaft wipers 105, 106 and 107 one ste at a time until 7 the said wipers are carrie into engagement with the normal conductors 160', 161 and 162, the first two of which lead to the line terminals of the desired subscriber. Also, when the vertical line relay 108 energizes, the spring 157 is pressed into contact with the sprin 154, thus again closing an energizing circuit through the private magnet 114 which again operates and locks itself in an operated position] The deenergiza tion of the rotary line relay 109, when the rotary impulse tooth 25 separates the springs 19 and 30, causes the locking circuit of'tho private magnet 114 to be again interrupted. The private magnet deenergizes, and one of two results occurs, namely the release of the side switch from second to third position, or the so-called busy-release of the connector, which will'bedisclosed hereinafter. Suppose the former rebridgln wipers 115, 116, 117,113 and 119 in contact with their respective contact points in third position. Tl1en,when the side switch passes to third position a guarding potential is established for protecting the called line. This potential extends from ground Gr through the side switch wiper 119 to the shaft wiper 107 which engages theprivate contact of the called line. The said guarding potential also closes an energizing circuit through the cut-off relay 163 of the first-selector C, thereby removing the bridge formed by the rotary and vertical line relays 114 and 115 of the selector C. The energizing circuit for the relay 163 may be traced from ground G to the private wiper 107, thence through the private normal conductor 162 switch shaft springs 116' and-117" to the bridge-cut-ofi relay 163, thence to the battery lead 139 and through battery B to ground G. Of course, when the relay 163 energizes it separates the springs 118 and 119 from the springs 120* and 121", thereby disconnecting the relays subscriber presses the signaling button 31, whereby the spring 32 is placed in contact with the contact point 33, as a result placing in direct connection the vertical and rotary line conductors 27 and 28. This now causes an increase of current-flow throughv t the connector vertical line relay 108. will be remembered that the connector side switch has-passed from second to third .po-

- springs 154 and 156 into contact the ringer relay 112 is energized by a flow of current from ground G through the springs 154 and 156, side switch wiper 117, contact point 164, ringer relay 112 to the bat lead 139,

and from battery B to groun -G. The ringer relay, upon energlzing, shifts the springs 165 and 166 out of contact with the springs 167 and 168 and into engagement with the springs 169 and 170.' This results in separating the callin subscribers line from the called subscri rs line, and in g across the line of the latter the terminals of the ringer generator H. The signaling current is therefore, sent from the ri r generator H to the ringergenerator .114and 115 from the battery terminals. To signal the calledsubscriber, the calling sprmgs 169 and 165, side switch 115, shaft I wiper 105, normal conductor 160, vertical conductor 171, condenser 172, ringer 173,

, 188 in contact, whereby a series circuit is switch hook 180, thereby removin 174 and 175, rotary impulse springs I sp s 1 6 and 177 to the rotary lme conductor- 178, normal conductor 161, shaft wiper .106, side switch wiper 116, ringer relay springs 166 and 170, back to the generator H. soon as the calling subscriber ceases to press the signaling button 31 of the ringer relayv 112 becomes deenergized, and the springs 165 and 166 resume their normal position in contact with the springs 167 and 168. The subscriber A, in response to the signal, removes the receiver 179 from tfie t 'e ringer 173 from across his line and bri ging, instead, the secondary circuit which includes the receiver 179, the secondary winding 181 of the induction coil 182, secondary springs 183 and 175 and rotary impulse rin 176 and 17 7 The local transmitter circuit is closed as soon as the springs 185 and 186 engage in contact. The two substations #5000 and #2220 are now connected over the circuit shown by heavy lines in Figs. 1 and 2.

The release of the central office apparatus 3 occurs when the calling subscriber restores the receiver 2 to the switch hook 3, thereby breaking the connection between the springs 6 and 7 at the substation, whereby the energizingcircuit through the rotary line relay 109 of the connector E is broken-that is,

the line conductors 27 and 28 are disconnected. The rotary line relay 109 of the connector E, upondeenergization, permits the sprin 154 and 155 to disengage, thereby breakmg the circuit through the releasing relay 113. The releasing'relay 113in turn .deenerfiizes and places the locked springs i 131 an "40 129' in contact with the spring 130, thereby closing an energizing circuit through the'release relay 121. This circuit extends from ground Gr through the relay 121, springs 131, 129 and 130 to the-'batte lead 139, andthr'ou'gh battery B to ground As the relay armature 133 returns to normal 0- sition the latch 132 slides upon the beve ed member 134 and unlocks the springs 131 and 129, as previously explained. The rela 121, upon energizing, closes the springs 18 and closed through the release relay 94 of the selector D and release magnet 120 of the connector '13. This circuit extends from ground G at the selector D to the contact point 153, side switch wiper 82, release reay 94, conductor 149, private'shaft'wiper 87 ,conductor 189, through the springs 187 and 188, releasemagnet 120 tot e battery lead 139, and through battery B to ground G. The release niagnet 120, being thus suplied with current, energizes and o crates 3 1n the well-known manner to restoret e corrnector shaft and shaft wipers to their normal position. The release relay. 94 of the selector D -also energizes and places the vcircuit extends from springs 190 and 191 in contact, whereby 0. clrcuit is completed through the release magnet 77 of the selector D in series with the release relay 65 of the first-selector C. This ound G at the selector C through the si e switch Wiper 40, release relay 65, private wiper 37 release relay springs 191 and 190, through the winding of the release magnet 77 to the battery lead 139, and through battery B t0 7 ground G. The release magnet 77 in turn operates to release the second-selector D. Also, when the armature is attracted, the s end 103 pressesthe latch 100 out of engagement with the spring 102,thus allowing the 80 locked springs 102 and 101 to disengage and return to normal position. The release relay 65 of the selector C also energizes and places the springs 192 and 193 incontact, whereby 'an energizing circuit is closed through the release magnet 64 at the selector 0. This circuit extends from ground through the springs 193 and 192 to the relay 64, to the battery lead 139, and through battery B to ound G. The release magnet 64 operates to press the latch 31 out of engagement with the spring 32, and to restore the first-selector shaft 34 to normal position.

The busy release of the connector E follows as a result of the deenergization of the rotary line relay 109, if the called line is busy. If, when the private magnet 114 deenergizes for the last digit, the called line is busy a ground impulse is transmitted from the shaft wiper 107 to the side switch 1 wiper 119, contact point 194 through the springs195 and 196 to the release magnet 120, thence to the battery lead 139, and through battery B to ground G. The re-' lease magnet, upon energizing, releases the 1 connector switch shaft and restores the con-- nector side switch to its first position, returning the vertical magnet to the control of the vertical line relay 108; therefore, if the calling subscriber (Fig. 1) now presses 110 the signaling buttonv 31 and energizes the vertical line relay 108, the latter -now operates the vertical magnet 110. .The vertical magnet in turn so raises the switch-shaft that the normal post 126 permits the switch shaft sprin 127 to engage the contact point 128, and a usy signaling current is sent to the calling subscribers station. The calling subscriber, upon hearing the busy-signal, will understand that the desired line is in service, and will release the switching a paratus over the same-circuits previous y described. The functions of the relay 63 of the selector C and the relay 95 of the selector D are to release before the side switch 3 has passed to third osition. u pose that in making a call t e selector O as been operated and established connection with the selector D, and that-it is desired to release the selector 0 and make a new call. In

that event, when the subscriber restores the receiver 2 to the switch-hook 3 and separates the line conductors 27 and 28, the energizing circuit through the rotary relay 90 is then broken, and the springs 91 and 93 separate, whereby the circuit through the release relay 95 also becomes broken. The springs 102 and 99, which are locked in con tact, now engage the spring 101, whereby an energizing circuit is completed through the release magnet 77 of the selector D in series with the release relay of the selector C. Thiscircuit extends from ground G through the release relay 65, shaft wiper 37, through the springs 102, 99 and 101, side switch 83, contact point 197 to the release magnet 77, thence to the battery lead 139, and through battery B to ground G. The release magnet operates, as before, to release the selector; D, and the release relay 65 energizes and closes a circuit through the release magnet 64, as above. Similarly, the selector C may be released while the side switch is in first or second position by thebreaking of the energizing circuit through the rotary line relay 61, thus permitting the springs 140 and 141 to disengage, whereby the circuit through the private magnet 43 and release relay 63 is also broken. The

locked springs 14-2 and 32' engage the spring 143, thus closing a circuit through the re-' lease magnet 64.; This circuit extends from ground G through the springs '32, 142 and 143, side switch'wiper 42, contact point 53 to the release magnet 64, thence to the battery lead 139, and through battery B to ground G.

The relay 63 may be wound toany suitable resistance, but good results have been obtained when said relay is wound to a resistance of twenty-three hundred ohms; the release relay 95 may be wound to. a resistance of twenty-three hundred ohms; the

vertical line relays 59, 89 and 108 to five hundred ohms; the rotary line relays 61, 90 and 109 to five hundred ohms; and the substation resistance coil 29 to three thousand ohms.

From the foregoing it will be seen that by my invention I provide improved means for controlling a. plurality or series of automatic step-by-step switches without employing operating grounds at the substations.

In other words, I employ a series of switches for trunking a calling subscriber into con-' nection with a called subscribers line, and do so by improved means comprising line circuitsincluding both sides of the line in series, no grounds being necessary outside of the central station or exchange for controlling the trunking switches and connectors. In this way the subscribers telephone lines are free from operating grounds outside of the exchange or central station,

and all line circuits employed for controlling, theexchange apparatus are of an en- 4 tirely metallic character and do not include the ground. The advantages accruing from the use of nongrounded telephone lines and substations are many, and will be obvious to those skilled in the art.

. \Vhat I claim as m invention is:

1. A telephone exc ange system co'mprising a telephone line, an automatic switch provided with a switch shaft supported for both endwise and rotary motion, means for closing the two sides of the line together to move the shaft endwise, means including a I line relay responsive to such closing of the ing a telephone line, an automatic switch provided with a bank of contacts arranged in a plurality of levels, a rotary switch. shaft adapted to be raised'to any one of said levels, a subscribers device for closing together the-two sides of the line, means including aline relayresponsive to the clos ing of the line for raising the switch shaft,

adapted to step the latter up to any level, according to the number of times the line is closed, means for automatically rotating the shaft at any level to find an idle contact therein, means for cutting oil theline relay while the shaft is in its rotated position,

and 'means for restoring the switch shaft to normal position by the opening' of the line;

3. A telephone exchange system comprising a subscribers telephone line, an auto-- matic switch provided with .a rotary and endwise movable switch shaft, a line relay for controlling the endwise movements of said shaft, means including another line relay for controlling the rotation of the shaft, line circuits for energizing said relays,

and means for cutting off said relays while the shaft is in its rotated position, each line circuit including the two sides of the tele.-. phone line in series.

-4..A telephone exchange system compriss ing a subscribers telephone line including a pair of talking con uctors, an automatic switch, a rotatable calling device adapted by its backward rotation to intermittently close together the two talkingconductors'of the telephone line, a line relay in said switch for responding to the intermittent, closing of the line, means for thereafter cutting off said relay, and means for "restoring the switch to normal position by. opening the line. r.

5. A telephone. exchangeisystem comprisinga calling telephone line, a called teles phone line, a progressively movableselector talking circuit and extendin from the selector to the connector, and a t ird or trunk release relay for controlling said release circuit.

6. A telephone exchange system comprising a calling telephone line, a called tele phone line, trunk lines including a pair of talking conductors and a separate release conductor, automatic switches for uniting said trunk lines to establish a connection between said telephone lines, means for. signaling the called subscriber by closing together the two sides of the calling line after the said telephone lines are connected together,

apparatus for releasing said switches, and a,

circuit including said release conductor and extending from one switch to another for operating said apparatus.

7 Atelephone exchange system compris ing telephone lines each including a pair of talking conductors, automatic connectors less in number than said telephone lines, selectors less in number than the telephone lines, subscribers individual switches corresponding in number tothe telephone lines, subscribers devices for closing together the two sides of the lines to. control said individual switches and selectors and connectors, line circuits by, which the said individual switches and selectors and connectors are controlled to establish a talking circuit between two of said telephone lines, each line circuit including said pair of talking conductors of a calling telephone line in series, and means including release trunks separate from the talking circuit and extending respectively from said individualswitches to said selectors and from said selectors to said connectors for restorin said individual switches and selectors an connectors by the opening of the callin lines.

8. A telephone exc iange system comprising a second selector, a pair of talking conductors extending thereto, and a battery having one pole grounded, said selector provided with a vertical line relay permanently connected to nongrounded battery, with a rotary line relay permanentl grounded battery, said re ays normally bridged across said talking conductors, and

with means for disconnecting said relays from said talking conductors.

9. A telephone exchange system compris-- ing a pair oftalking conductors and a connected to rotary line relay normally connected to one of said conductors, anenergizing circuit for said relay, means for disconnecting said relay from said conductor, means for causing short interruptions 1n the energizing circuit of said relay, and a slow acting relay adapted to energize when the said line relay is ener ized, and adapted to remain energize durin the short interruptions in the energizin circuit of the said line relay.

10. A telephone exchange system comprising a selector provided with a side switch, a trunk line including a pair of talking conductors leading to said selector, a circuit including said talking conductors in series for controlling the operation of said selector, a

release-relay for releasing said selector while the side switch is in first or second position, and a release relay for releasing the said selector when the side switch is in third position. I a

11. A telephone exchange system com rising a release relay provided with t iree springs, and a catch on one of said springs adapted to lock the other two of said springs together when the release relay energizes, a side switch wiper connected with one of the springs, a trunk release conductor, a selector having a private wiper, said trunk releaseconductor connecting another of said springs withvsaid private wiper, said catch causing the locked pair of springs to be brought into electrical connection with the third spring when the release relay deenergizes to place the side switch wiper in electrical connection with the said trunk release conductor.

12. A telephone exchange system wherein the subscribers lines each include a pair of talking conductors and wherein the central ofiice apparatus is controlled over circuits including the said talking conductors in the side switch of the seconll selector is in u first or second position.

13. A telephone exchange system comprising a selector providedwith a side switch,

a release relay provided with a pair of springs, means for locking said springs to,- gether, a release 1nagnet. a rotary line relay, a. switch shaft adapted to be raised step by step, a pair of springs adapted to be operated by said shaft, an armature for said release magnet, said armature ada ted to unlock the release relay springs wien the release magnet energizes, and a private magnet ,only while the said side switch is in first position.

14. A telephone exchange system wherein a pair of talking conductors lead to an automatic switch, a switch shaft, a rotary line relay normally connected to one of said talking conductors, means for disconnecting said relay from said talking con- ,ixluctor, a private magnet, and an energizing circuit for said private magnet controlled by said switch shaft and rotary line relay, said shaft provided with means for raising and rotating it, means operated by said shaft and relay for setting up the said circuit while the rotary line relay is energized and the switch shaft out of normal vertical position but in normal rotary position, said energizing circuit when established adapted to be broken either by the rotation of-the shaft, by the deenergizing of the rotary line relay, or by both.

15. A telephone exchange system comprising a first selector, asecond. selector provided with a side switch,-a trunk line including a air of talking conductors leading to said second selector, arotary line relay normally connected to one of said talking conductors, means for disconnecting said-relay from said talking conductor, and means for energizing said relay after the first selector extends connection to the second selector adapted to maintain the relay energized as long as the side switch of the second selectorren'iains v in first or second position.

16. A telephone exchange system comprising a second selector provided with a vertical side switch wiper, a vertical line relay,- a vertical line wiper, a trunk conductor adapted to be switched by 'the switch wiper from the vertical line relay to the vertical line wiper, a rotary side switch wiper, a rotary line relay, a rotary line wiper, a rotary trunk conductor adapted to be switched by the rotary side switch wiper from the rotary line relay tothe rotary line wiper, a,rotary magnet, aside switch wiper for closing circuit through the rotary magnet while the sideswitch is in second position, a private magnet, a side switch wiper adapted to close circuit through the private magnet to lock the side switch in second position and to maintain circuit through the rotary mag- 'net, a private wiper, bank contacts adapted to be engaged bv said private wiper, said energizing circuit maintained through the rotary magnet adapted to be opened as soon as the private wiper passes out of engagement with busy bank contacts, a release magnet, a release relay spring, and a side switch wiper for maintaining the reing said magnet.

lease magnet in connection with the said release relay spring while the said switch is in first or second position, adapted for breaking such connection between the release magnet and the release relay spring when the side switch passes to third position. V

17 .A telephone system comprising a sec-. ond selector provided with a private magnet, a switch shaft and springs controlled thereby, a rotaryline relay, a back rtlease relay, a private wiper, and aside switch provided with a SWItClI wiper, said private magnet having a plurality of energizing circuits whereof one 'is controlled by the shaft controlled springs and the rotary line relay, another of said circuits being controlled by the private magnet itself and including said switch wiper and back-release relay and theprivate wiper.-

18. A telephone system comprising a battery having one pole grounded, a connector provided with a rotary line relay having one terminal thereof permanently connected to ground, a vertical line relay hav-. ing one terminal thereof ermanently connected to the non-grounded terminal of .the battery. a trunk line including a pair of talking conductors and a separate conductor leading to said, connector, a selector for establishing connection with said three conductors, a magnet for releasing said connector, and a circuit including said separate conductor and extending from sald selector to sa d connector for operat- '19. A telephone system comprising a s ec- 0nd selector, a connector, a trunk line including a pair of talking conductors and a separate-conductor leading to said connector, a line relay for controlling the operation of said connector to extend a connecing said connector, and a circuit including said separate conductor extending from said selector to said connector for operating said magnet.

'20. A telephone system wherein the trunk V lines extending betweehthe automatic switches each include a pair of talking con-.. ductors and a separate conductor, fa rotary line relay, a pair of line conductors, a substation high resistance coil, a vertical line, relay, a. circuit for energizing said rotary line relay, said circuit including said line conductors, said resistance coil, and said vertical line relay, the resistance of said circuit being adjusted to permit the operation of the rotary line relay and prevent the operation of the vertical line relay, means for short circuiting or shunting the resistance coil to lay, a rotary gizing circuit rotary line relay,

three conductors; a slow-acting release re-.

lay adapted to energize when the said rotary line relay is energized, a magnet for releasing said connector, and a circuit including said se arate conductor and extending from said se ector to said connector for operating said magnet.

22. An automatic telephone exchange system comprising a connector provided with a a slow-acting relay, an energizing circuit said slow acting relay being provided with springs, and means for locking said springs together when the slow acting relay is ener-' gizing, said slow acting relay adapted to remain energized during short interruptions of the energizing of the said rotary line relay.

'23. An automatic telephone exchange system comprising a connector and means for seizing said connector, the said connector being provided with a slow acting relay adapted to remain energized from the time the connector is seized until the calling subscriber releases, a rotary line relay, means for deenergizing said rotary line relay when the calling subscriber releases, means by which the deenergizing of said rotar. line relay causes the deenergizing of 'sai slow acting relay, a release magnet, a beveled sto thr de springs and with a latch for momentarily uniting said springs in electrical contact, said latch adapted to strike said stop when said slow acting relay is deenergized, a

release magnet and an energizing circuit I therefor adapted to be opened by the separation of two of said springs, substantially as set forth.

24. A, telephone exchange system comprising a private magnet, a vertical line reline relay, and a locking enerfor the private magnet adapted to be set up by the vertical line relay and adapted to be broken down by the rotary line relay.

241A telephone exchange system comprising a vertical line relay, a rotary line relay,

a side switch, and a locking energizing circuit adaptedto be set up by the vertical line relay while the side switch is in first or second positionand adapted to be broken by the rotary line relay. I

26. A telephone system comprising a private magnet, a side switch and private wiper,

for the slow acting relay,

the private said slow acting relay provided witha rotary line relay and arelease magnet, a circuit for initially energizing said private magnet, a locking circuit for said private magnet controlled by said rotary line relay, a couple of energizing circuits for said re lease magnet, one of which circuits is controlled by the private ma et adapted to be set up while the side switch is in second position and the private wiper on a grounded contact point at the instant that the rotary line relay breaks the locking circuit of the prlvate magnet.

27. A telephone system comprising a vertical line relay, a side switch,'a rotary magnet controlled by the vertical line relay while the side switch is in second position, a shaft and shaft wipers rotated therebyin a step by step manner, a private wiper, a release magnet, an energizing circuit therefor, established while the side switch is in second position, comprising private magnet springs,

private wiper stops upon a d grounded contact point, an

a locking energizing circuit for magnet adapted to be established by the vertical line relay upon its first operation, after the side switch passes to second position, in order to maintain the said private springs separated, and to prevent the establishment of the said release magnet energizing circuit while the private wiper is bein rotated. I

28. A telep one system comprising a con- 'nector side switch, vertical androtaryline relays 'for operating said side switch, and a private magnet, said side switch controlled by the private magnet and adapted to shift from first to second position and from second to third position, the shift from first to second position produced by the vertical line relay. energizing the 'rivate magnet and locking the latter, and by the rotary line relay subsequently breaking down the said locking circuit,- the shift from second to third position produced by'the vertical line relay again energizing and locking the private magnet, and by the rota line relay subsequently breaking down the ocking circuit.

29. A tele hone system comprising a vertical line re ay, a vertical magnet, and a private magnet combined to energize to.- gether.

30. A telephone system comprising a selector, a side switch therefor, another selector for extending connection to said first mentioned selector, a rotary line relay for said first mentioned selector adapted to energize as soon as the first mentioned selector is seized, a slow acting release relay energized thereby, said slow acting release relay remaining in readiness to release said selectors if the subscriber should desire to do so before said side switch passes to third position.

' release circuits for the selectors controlled by the connectors, telephone lines, and line circuits for successively controlling one or more of said trunk-selectors and a connector to extend connection to a called telephone line, each circuit including the two sides of a calling telephone line inseries, and means for releasing the selectors and connectors by the opening of a connected telephone line.

32. A telephone system comprising trunkselectors, line relays for said selectors, op erating circuits controlled by said relays, means for cutting off said line relays, automatic connectors, line relays for said connectors, circuits controlled by said last-mentioned relays for controlling the operation thereof to extend connection therefrom, a source of operating current, said source of current normally bridged 'between the relays of the connectors, metallic line circuits for controlling the said relays, and trunk release circuits for the selectorscontrolled by the connectors.

33. A telephone exchange system comprising telephone lines each including a pair of talking conductors, automatic connectors less in number than said telephone lines, provided with means having vertical motion from one operative level to another to select groups or divisions ofthe exchange, and rotary motion in any selected level to connect with a line therein, selectors less in number than the telephone lines, subscribers individual switches corresponding in number to the telephone lines, subscribersdevices for closing together the two sides of the lines to control said individual switchesand selectors and connectors, line circuits by which the said individual switches and selectors and connectors are controlled to establish a talk ing circuit between two 0f said telephone lines, each line circuit including said pair of talking conductors of a calling telephone line in series, and means including release trunks separate from the talking circuit and extending respectively from said individual switches to said selectors and from said selectors to said connectors for restorin said individual switches and selectors an connectors by the opening of the calling line.

34. A telephone exchangesystem comprising a second-selector, a pair of talking conductors extending thereto, and a battery having one pole grounded, said selector pro-u vided with means having vertical motion from one operative level to another to select groups or divisions of the exchange, and rotary motion in any selected level to connect with a line therein, and provided also with a vertical line rela permanently con nected to nongrounded battery, with. a rotar line relay permanently connected to grounded battery, said relays normally bridged across said talking conductors, and

means for disconnecting said relays from said talking conductors.

35. A telephone exchange system comprising a selector provided with means'hav- 111g vertical motion from one level to another to select groups or divisions of the I exchange, and rotary motion in any selected level to connect with a line therein, and provided also with a side switch, a' trunk line" includin a pair of talking conductors leading to sald selector, a circuit including the said talking conductors in series for controlling the operat-ion of said selector, :1

"release relay for releasing said selector while I the side switch is in first or second position, and a release relay for releasing the said selector when the side position.

36. A telephone exchange system comprising a selector provided with means having vertical motion from one operative level to another to select groups or divisions of the exchange and rotary motion in any selected level to connect with a line thereinand provided also with a'side switch, a release relay provided with a pair of springs, means for locking said springs together, a release magnet, a rotary line relay, a switch shaft adapted to raised step by step, a pair of springs adapted to be operated by said shaft, an armature for 'said release magnet said armature adapted groups or divisions of the exchange and rotary motion in any selected level to connect with a line therein, and provided also with a side switch, a trunk line including a pair of talking conductors leading to saidv 1y connected to one of said talking conductors, means for disconnecting said relay from said talking conductor, and means for energizing said relay after the first selector switch .is in third 1 second selector, a rotary line relay normalextends connection to the second. selector adapted to maintain the relay energized as long as the side switch of the second selector remains in first or second position.

38. A telephone system comprising a battery having one pole grounde a connector provided with means having vertlcal motion from one level to another to select groups or divisions of the exchange, and rotary motion in any selected level to connect with nection with said three conductors, a magnet for releasing said connector, and a 011' cuit including said separate conductor and extending from said selector to said connector for operating said magnet.

39. A telephone system comprising a second' selector, a connector provided with means having vertical motion from one level to another to select groups ordivisions of the exchange and rotary motion in any selected level to connect with a line therein, a trunk line including a pair of talking conductors and a separate conductor leading to said connector, a line relay for controlling the operation of said connector to extend a connection therefrom, a circuit including said pair of talking conductors-in series for energizing said line relay, means for closing said circuit as soon as the selector seizes said trunk line, a magnet for releasin said connector, and a circuit including said separate conductor and extending from said selector to said connector for operating said magnet.

40. An automatic telephone exchange system comprising a connector provided with means having vertical motion from one operative level to another to select groups or divisions of the exchange, and rotary motion in any selected level to connect with a line therein, and provided also with a rotary line relay, a trunk line including a. pair of talking conductors and a separate conductor leading to said connector, a selector for establishing connection with said three conductors, a slow-acting release relay adapted to energize when the said rotary line relay is' energized, a magnet for releasin said connector, and a circuit including said separate conductor and extending from said selector to said connector for operating said magnet. p

41. An automatic telephone exchange system comprising a connector provided with means having vertical motion. from one operative level to another to select groups or divisions of the exchange, and rotary motion in any selected level to connect with a line therein, and provided also with a rotary line relay, a slow-acting relay, an energlzmg circuit for the slow-acting relay, said slowfacting rela being provided with a pair means for locking said springs together when the slow-acting relay ed to remain energized during short interruptions of the energizing of the said rotary line relay.

42. An automatic telephone exchange system comprising a connector, means for seizing said connector, the said'connector being provided with means having vertical motion from one operative level to another to select groups or divisions of theexchange, and rotary motion in any selected level to connect with a line therein, and also pro vided with ajslow-acting relay adapted to remain energized from the time the connector is seized until the calling subscriber releases, a rotary line relay, means for deenergizing said rotaryline relay when the cal]- ing subscriber releases, means by which the deenergizing of said rotary line relay causes the deenergizingof saidslow-acting relay, a release magnet and a beveled stop, said slow-acting relay provided with three springs and with a latch for momentarily uniting said springs in electrical contact, said latchadapted to strike said stop when said slow-acting relay is deenergized, a release magnet and an energizing circuit therefor adapted to be opened by the separation of two of said springs. I

43. A telephone system comprising automatic trunk-selectors, automatic connectors provided with means having vertical motion from one level tov another to select groups or divisions of the exchange, and rotary motion in any selected level to connect with a line therein, trunk lines each including a pair of talking'conductors leading to said connectors, trunk-release circuits for the selectors controlled by the connectors, a variablyrotative calling dial at each substation, a source of operating current, said 1 provided with a bank of contacts arranged in a plurality of levels, and with a rotary switch shaft-adapted to be raised to any one of said levels in accordance with a. digit of the called number, a subscribers device for closing together the-two sides of the line,

adapted to come to rest before actuation thereof to transmit impulses for the next digit, means including a line relay responsive to the closing of the line for raising the switch shaft, adapted to step the latter up to any level, according to the number of times the line is closed, means for automatically rotating the shaft at any level .to find an idle contact therein, means for cutting off the line relay while th shaft is in its rotated position, and 'meansfor restoring the switch shaft .to normal positionvby the opening of theline. i

45. In a telephone exchange trunking sys-.

tem, a subscribers telephoneline, an autos maticswitch provided with a rotary and endwise-movable switch shaft. a line relay for controlling theendwise movementsnof said shaft, means including another line rela'y'for controlling the rotation of the shaft,

line" circuits for energizing said relays, means for cutting off said relays while the shaft is in its rotated positiom'each line circuit including the two sides of the telephone line in series, and a calling mechanism for controlling said circuits, adapted to come to rest upon the completion of the endwise motion of said shaft.

v 46. In a telephone exchange trunking system, asubsc'ribers-telephone line, an auto- 'matic switch provided with a rotary and endwise-movable switch shaft, another automatic switch, a trunk line including a pair of talking conductors and a separate conductor leading from said first switchto said other switch, means including a line circuit for controlling the rotation of the shaft to seize said trunk line, eachline circuit including the two sides of the'telephone line and said pair of talking conductors all inserics, means for controlling said circuits adaptal to return to normal upon the completion of the endwise movement ofsaid shaft, release mechanism forsaid first switch, and a circuit including said separate conductor and controlled by said other switch for operat-.

ing said mechanism. a

47; In atelephone exchange trunking system, telephone lines each including a pair of talking conductors, automatic connectors less in number than, said telephone lines, se-

lectors less in number than theftelephone lines subscribers individual switches corresponding in number tot-he telephone lines, subscribers devices for closing together the two sides of the lines to control said individual switches and selectors and connectors, each device adapted to come to rest after one digit and before calling the next digit, line switches and selectors and connectors are 'controlled to establish a talking circuit bea tween two of said telephone'lines, each line circuit including the two sides of a calling telephone line in series, and means including release trunks separate from the talking circuit and extending respectively from said. individual switches to said selectors and from said seledors to said connectors for restoring said individual switches and selectors andic'onnectors by the opening of the calling line. i f 1 48. In a telephone trunking system, tru nktrun -releas e circuits for the selectors controlled by the connectors, and means for controllingsaid relays adapted to come to rest after each separate operationv thereof for each digit of the callednumber.

49. In an automatic telephone exchange system employing bridging line relays, a

calling telephone line, a calledtelcphone line,-a series of automatic switches for extending connection from the'calling line to the called line, having provisions for automatically reducing the number-ofbridges across the talking circuit during the =establishmentthereof, three conductor trunks tweenisaid switches, and a plurality of line: circuits by which said switches are succes sively controlled, each said: line c-ircuit in cluding the two sides of the calling hne 1n series.

50. In a telephone exchange system employing bridging line relays,,a calling tele-. phone line, :1 called telephone line, means including a plurality of selectors and a connector for extending connection from the calling line to the calledline, having lprovisions for automatically reducing the number of bridges across the talking circuit,

during the establishment thereof, three-0on5" ductor trunks between said switches, "line line circuits for controlling the connector,

each line circiut including the two sides of switch shaft, having provisions for automaticall reducing the number of bridges across t e talking circuit during the-establishment' thereof, means including a line-circuit for controlling the endwise movements 1 of the switch shaft, means including a line in circuit for controlling the. rotation of the V shaft, and a trunk-release circuit for re- OllCllltS by which the sald indivldual storing said switch, each line circuit inin series. v

52, In a telephone system employing bridging line relays, a line, a plurality of electrically-pro elled and step-by-step actuated switches raving provisions for automatically reduclng the number of bridges lishment thereof, three-wire connections be i tween saidswitches, line circuits for suecessively controlling said switches, andfl a'" subscribers device for intermittently clos ing together the two sides of the line to 10 circuits for controlling the selectors, and

across the talking circuit during the estab-.-

establish said circuits, each line circuit including the two sides of the line in series.

53. In a telephone exchange stem emlploying bridging line relays, telep one lines, automatic connectors less in number than saidtelephone lines, selectors less in numher 'than the telephone lines, having provisions for automatically reducing the number of bridges across the talking circuit during the establishment thereof, subscribers individual switches corresponding in number to the telephone lines, subscribers devices for closing together the two sides of the lines to 'control 'said individual switches and selectors and connectors, line circuits by which the said individual switches and selectors and connectors are controlled, each line circuit including the two sides of a callin telephone line in series, and means inc uding release trunks for restoring said individual switches and selectors and connectors by the opening of the calling lines.

54. In a telephone system employing bridging line relays, subscribers te ephone lines, automatic means for trunking a call ing ,line into connection with a called line, having provisions for automatically reducing the number of bridges across the talking circuit during the establishment thereof, including three-wire trunks, and successive line circuits for controlling said automatlc trunking means, each line circuit 1ncluding the two sides of the calling telephone line in series.

55. In a telephone system employing bridging line relays, trun selectors having provisions for" automatically reducing the number of bridges across the talkin circuit during the establishment" thereo line relays for controlling said selectors, means for cutting off said line relays, automatic connectors, line relays for said conn tors for controlling the operation thereof to extend connection therefrom, a source .ofop- -eratin current, said source of current normally ridged between the relays of the con-. nectors, and trunk-release cireuits for the selectors controlled by the-connectors.

56. An automatic tele hone exchange system comprising subscri ers lines, a, seriesof automatic switches for-trunking a calling subscribers line intoconnection with a called subscribers line, a bridge contain-i igg an operating element and av ridge cut- 0 relay for each subscribers line, trunk lines each including a pair of talking conductors and a separate conductor between said switches, circuits each including a pair of said talking conductors in series for operating said switches, means independent of the earth at the calling subscribers station for controlling said circuits, a magnet for releasing the final one of said series of switches, and a circuit including said separate conductor of one ofsaid trunk lines for'operating said magnet.

out 01f relay for each telephone line, trunk.

lines, each including a pair of talking conductors and a separate conductor between said switches, a plurality of line circuits by which said switches are successively controlled, each said line circuit including said pair of talking conductors of the calling hne in series, a magnet for releasing the final one of said series of switches, and a circuit including said separate conductor of one of said trunk lines for operating said magnet. ,7

58. A telephone exchange system comprising a calling telephone line including a pair of talking conductors, a called telephone line, means including a. plurality of selectors and a connector for extending connection from a calling line to a called line, a bridge containing an operating element and a bridge cut off relay for each telephone line, trunk lines each including a pair of talking conductors and a separate conductor between said switches, a plurality of line circuits for controlling each of said selectors, a plurality of line circuits for controlling said connector, each of said line circuits including said pair of talking conductors of the \calling line in series, a magnet for rei a pair of talking conductors and a separate conductor between said switches, means for signaling the called subscriber by closing together said pair of talking conductors of the calling line after the two lines are con nected together, a magnet for releasingone of said switches, and a circuit including said separate conductor for operating said magnet. a

60. A telephone exchange system comprisin telephone lines each including a pair 0 talking conductors, a bridge containiriiig an operating'element and a bridge out o relay for each telephone line, automatic connectors lessin number than said telephone lines, selectors less in number than the telephone lines, subscribers individual switches corresponding in number to the telephone lines, trunk lines each including a pair of talking conductorsand a separate conductor, some of said trunk lines extending between said selectors and connectors and other of said trunk lines extending between said individual switches and selectors, subscribers devices for closing together said pair of talking conductors of the telephone lines to control said individual switches and selectors and connectors, line circuits 'by which said individual switches and selectors and connectors are controlled, each line circuit including said pair of talking conductors of a calling telephone line in series, and means including release circuits for restoring said individual switches and selectors and connectors by the opening of said pair of talking conductors of the calling line, each said release circuit including said separate conductor of one of said trunk lines.

61. In a telephone systema called telephone line, an automatic switch, a. trunk line including a pair of talking conductors leading thereto, means for making connection to said trunk line, means for controlling said pair of talking conductors in series to control said switch to connect with said called line, said switch having a controlling magnet connected to one of said talking conductors, and means whereby said magnet is disconnected from said talking conductor during the use of the latter for talking purposes.

62. In a telephone system, a. switch, means I including a release-magnet. and a release magnet circuit for releasing the same, a

slow-acting relay controlling the release magnet circuit throughout the operation of the switch,'and a quick acting relay directly controlling the release magnet circuit independently of ,said slow-acting relay after the switch has operated.

63. 1 In a telephone system, a pair of lines, a pair ofautom tic progressively movable switches operable successively for trunking from one line to another for setting up a connection between said lines, release means for breaking the connection at each switch, quick relays and slow relays the system -for controlling said release means, and

means controlled solely through the medium of said quick acting relays for operating said release means to break the connection.

64. In a telephone system, a switch, means for releasing the same including a relay slow to release controlling a release magnet during the entire setting operation of the switch, a line relay controlling said slow relay a quick acting relay controlling the release independently of said slow relay after the switch has operated, and means for controlling the two sides of a calling line in series to operate said switch.

65. In a telephone system, a trunk, a switch for extending connection thereto, releasing means tor said switch including a slow-acting relay controlling the release continuously after the operation of the switch is started and until connection is extended to the trunk, and a quick acting relay controlled over the trunk for controlling the release after the switch has established the connection, and means for controlling the two .sides of a calling line in series to operatev said switch.

66. In atelephone system, a trunk, a switch for extending connection therefrom, releasing means for said switch including a release magnet and a relay slow to release its armature, said relay controlling the release magnet throughout the time the switch is operating, a quick-acting relay controlling the release magnet independently of said slow relay. after connection has been established from the trunk, and means for controlling the two sides of a calling line in series to operate said switch.

67'. In a telephone system, a trunk, a switch for selecting said trunk and for extending connection thereto, releasing means for said switch including a relay slow to re. lease its armature, said relay controlling the release during the entire time the switch is operating to select said trunk, and a quick acting relay controlled over said trunk for controlling the release of said switch after connection has been established with said trunk- 68. In a telephone system, means including switches having selecting motions in two intersecting planes for establishing a calling connection. means-for releasing the connection including release magnets, circuits for energizing said magnets, slow acting relays controlling the release circuits during the establishment of the call, and quick acting relays for controlling the release circuits during conversation independent of said slow acting relays.

69. In a telephone system, a switch, means for directively operating said switch in a primary movement and for automatically operating said switch in a secondary movement, a release magnet for restoring said switch, a slow-acting relay controlling said release magnet throughout the primary movement of said switch, and a quick acting relay controlling said release magnet independent of said slow acting relay after the secondary movement has been completed.

70. In a telephone system, a line terminating in an automatic switch, a line relay in said switch connected .to said line for controlling the operation of said switch, a slow acting relay controlled by said line relay, a release magnet controlled'bysaid slow relay while the switch is operating, means for disconnecting said line relay from the

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