US1207150A - Automatic telephone swtiching system. - Google Patents

Description

. A. H.'D YSON-.v-

AUTOMATIC TELEPHONE SWITCHING SYSTEM. v

APPLICATION FILED MAB. 8, 1915.

Patented Dec 5, 1916.

2 SHEETSHSHEET 1.

A. H. DYSON. AUTOMATIC TELEPHONE SWITQHING SYSTEM.

' APPLICATION FILED MAR. 22. 1915.

Patented; Dec. 53916.

2 SHEETS-SHEET 2.

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T WESTERN: ELECTRIC CQMEANY, INCORPORATED, A CORPORATION OF NEW YORK.

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Specification of Letters Patent.

lPatented Dec. 5, role.

Application filed March 8, 1915. Serial No. 12,810.

To all whom it may concern:

Be it known that l, ALFRED H. Dyson, a

citizen of the United States, residing at Montclair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Automatic Telephone Switching Systems, of which the following is a, full, clear, concise, and exact I "description.

cuits for switching apparatus used in automatic telephone systems.

One of the objects of this invention is the provision in a system in which the subscribers lines' are divided into a plurality of groups, of means whereby a series of relays definitely associated with the lines of said groups will be employed to select that group of contacts'in which a calling line terminates.

Another feature of the invention resides in the provision of circuits for controlling the operating mechanism which is common to a plurality of switches.

In the drawings Figure 1 shows a plurality of subscribers lines, each being in a different group, and the group selecting the case may be;

relays associated therewith; in Fig. 2 a selector switch and the common actuating mechanism are diagrammatically illustrated. together with the controlling circuits therefor; Fig. 3 is a view showing one of the endless worms and the supporting frame for the magnets mounted thereon.

The switch structure herein shown aside from the operating mechanism, may be substantially such as described in Patent No.

1,123,696 and will therefore be only briefly the elevating bar (3 of the switch is forced into engagement therewith by means of one of the idler pulleys 7 or 8 respectively, cause the brush shaft to be driven upwardly to its vset position or downward to normal as This invention relates to controlling cir-.

Carried by the shaft 1 are a plurality of interrupter brushes 9, 10 and 11, which in the movement of the switch shaft, are caused to traverse their respective commutators 0r lnterrupters (shown in Fig. 2) to control. the operation of the switch mechanism, as will later appear. l

The brushes of each of the sets 2 are normally held in a position so they will not engage the line terminal contacts by means of a controlling member 12 positioned between the two innermost b1 ushes of the set. I A rotatable trip rod 13 is mounted parallel to the shaft 1. This rod is provided adjacent each controlling member with a cooperating member by means of which the brushes may be released. These cooperating members are positioned at progressively increasing distances from the normal position of the controlling members 12. i

if the rod 13 is rotated during the preliminary upward movement of the switch shaft,

one of its cotiperating members will engage a corresponding controlling member 12 to release a set of brushes. Thus it Wlll be seen that the set of brushes to be tripped or released depends on the distance the shaft travels prior to the rotation of the trip are dispensed with and a single set of operating magnets and associated parts are provided to control the operation of a group of switches. The magnets which control the upward movement of the switch carriage I.

and the tripping of the desired set of brushes are mounted in one frame, and the release and down-dri e magnet is mounted in a separate frame. By means-of endless worms the frames are shifted into position so that the magnets carried thereby may control By this in-- vention the individual operatinglTlQCl'lEtIllSlTlS' the operation of any desired switch either to cause it to move upward to its setpbsition or to release it and return 1t to normal, as the case may require. As the operation of this mechanism will be readily under November 14, 1916.

drive drum 5 and the worm 28 are provided ever, a more complete description:v of this device will be found in patent issued to James L. McQuarrie, No. 1,20%,466, patented The idler pulleys 7 and 8, carried by the common actuating mechanism are adapted to force any. one of the elevating bars 6 into engagement with the power shafts A} and 5, respectively.

The ups-drive power drum le is provided at the end thereof with a friction disk 15. Extending parallel to the drum 1- bnt on the opposite side of the elevating bars 6 is a shaft 16 provided with an endless spiral groove 17.1 (See Fig. 8). Mounted on the endless worm 16 is a frame 18 indicated by dottedlines in Fig. 2, carrying a' follower 19 seated in the endless groove 17. The

shaft 16 with the spiral groove thereon will hereinafter-be referred to as an endless worm. This worm is provided at one end, adjacent thefriction drum 15, with a friction wheel 20. Secured to the end of the armature 21 of the electromagnet 22 is a link 23, to the outer end of which is rotatably secured 'a friction roller 24. Upon energization of the magnet 21 this roller is caused to operatively engage the power disks l5 and 20 and transmit a rotary motion from disk 15 to disk 20.v The up-drive clutch magnet 24 and its armature 25 are mounted in the frame 18. The idler pulley 7 is secured to the armature 25 in such a manner that upon energization of the magnet 24i the pulley will engage an elevating bar-6 and force it into operative engagement with the power drum 1. Also carried by the frame 18 is a brush selecting or tripping magnet 26. Pivotally mounted on the frame below the lowermost set of brushes .to the down-drive drum 5, but on the opposite side of the elevating bars. The downwith friction disks 29 and SQ-respectivaly, the operative relation of whigh is caused by the friction roller 31 carried by the armature of the electromagnet 32. Mounted on the frame adjacent to the ddwn-drive drum 5 are the holding pa'wls 33; one for each switch. These pawls are adapted to engage the perforations 35 in the bars 6 and insintain the switch shafts in their elevated positions. The frame 36, which is mounted on the lower endless worm 2.8, carries the electromagnet 37 which has the two-fold purpose of retracting the holding pawls33 and of forcing the bar (3 into engagement with the down-drive drum. This magnet 37 is provided with an armature 38, to the upwardly extending portion of which is secured the idler pulley 8 and afinger 40, adapted upon energization of said magnet to engage the downwardly extending end of a pawl 83 and cause it to disengage its bar 6.

v The brushes 51, 52, 54-, and 56 are carried by the upper frame 18, and in the movement of the upper common actuating ,mechanism from switch to switch, are arranged to traverse the contacts bank 57.

The brushes 58, 59, (30 and 61 are carried by the lower frame 36 and in the movement of the common release mechanism from switch to switch these brushes will traverse the contacts in the bank (32.

A. set of the contacts in each of banks 57 and are provided before each elevating bar G.

In the circuits shown in Figs. 1 and 2, the above described device is used as a line finder. This switch, as previously described, is a multiple brush structure. In practice five sets of brushes are usually provided, each adapted to traverse a section of the fixed terminals in the panel bank. Each section in the bank may be provided with as many fixed terminals as desired, one hundred being a common number, but in a line finder a smallernumber may be employed. Each section of the contacts on the panel represents multiple terminals of a group of subscribers lines.

Referring to Fig. 1, the subscribers station shownat the right represents oneof the 0 group ofv subscribers whose lines terminate on the lowermost section of the panel. The subscribers station next to the left represents one of the subscribers in the 1 group which subscribers lines terminate at the second section from the bottom of the panel bank. The middle subscribers' station is connected to terminals on the middle section of the contact bank and so on. While only two groups or sections of contacts are indicated in Fig. 2, it is to be understood that in the embodiment of the invention herein disclosed there will be five groups of line terminals. A pair of relays 65 and 66 which may be termed counting relays will be' provided for each group of lines. That is, for eachgroup of subscribers lines there willbe a. pair of relays 65 and 66 common to all the lines of the group. Associated with the five pairs of relays oi the said groups .is a double wound relay 67 and a relay 68. These relays being common in the acetate finder switches.

A sequence switch such as those whichscrve to control the CHCHllISllQIBHl shown 1s fully described in Patent No. 1,127,868. It

may be noted that inthe specification the numeral in brackets which follows a refercnce character used to designate a sequence. switch contact, indicates the position of the sequence switch, the time the circuit being traced completed. (in the drawings the numeral or numerals adjacent to a'sequcnce switch contact indicates the position or positions in whichthe contact is closed, except the controlling contact A which is open only the positions indicated.

Assuming now that the subscriber at substation S (Fig. l), initiates a call. by removing his receiver from the hook, a circuit will be completed from grounded battery through line relay 69, contact of cut-oil relay 70, the substation apparatus and back to ground through the left armature of cut-offrelay 70.

The sequence switch then moves from posi- Relay 69 will be energized and complete a circuit from ground through its armature and inner contact, conductor 71, armature and back contact of relay 65, conductor 72, sequence switchcontact .l (2), conductor 73 and left winding of relay 74 to grounded battery.

Before continuing the description, it may be noted that the finder switch next to be used in. Ending a calling line is preselected and that the common cpcrating mechanism is in association therewith. It should also be noted that the sequence switch of this preselected line finder stands in position 2. The manner in which thisvis accomplished will hereinafter appear.

V7 hen relay 7%: is operated it completes a circuit from ground through its right armature and front contact, sequence switch contact B (2); conductor 7 5, sequence switch Y motor magnet 76 to battery and ground.

tion 2 to position 'lhis interrupts the energizing circuit for relay 74 which falls back, completing through its right armature t Conductors a circuit from ground, sequence switch con tact 3(3) and sequence switch motor magnet 76 to battery and ground. This moves the sequence switch to position 4. In position i a circuit is completed from groundedbattery through the left winding of relay 74:, sequence switch contact J (4) conductor 77, relay 68, back contact of relay 67, conductor. '18, sequence switch contact G (4) to ground. Y

72, .77 and 76 are multipled to opt-responding sequence switch contacts of all the line finders of a group). Relays 74 and 68 are ener ized.

Relay 68 colnpletes a circuit from battery through relay 66, back contact as relay to ground; Relay 66 pulls up and completes 'ta'ct of relay 6?, conductor 78,

a circuit for itself in series with relay 65 through conductor 78 to groundat contact G (at). Relay 65 does not pull up, however; due to its being short circuited by the arms ture of relay 68.

Relay 7 4c completes through its right armature and sequence switch contact B l) a circuit for sequence switch motor magnet 76 and the sequence switch goes to position 5. in position '5 a locking circuit is established for relays 74: and 68, which extends from grounded battery through the left winding of relay 74, front contact and left armature of said relay, sequence switch contact J (5), conductor 77., winding of relay 68, back consequence switch contact G to ground.

Under the assumption that the common actuating mechanism is associated with they set of contacts in the bank 57 which are individual to the preselected switch to be operated in position 5 of the sequence switch, a circuit will extend from grounded battery through conducting strip 79, brush 51, the up-drive clutch magnet 24, brush 55, sequence switchcontact C (5)-and front contact and right armature of relay 7st to ground. The clutch magnet is energized and the brush.- shaft moves upward.

Just prior to reaching the first brush selecting position the interrupter brush 1O engages the, lowermost conducting segment of the interrupter 80. This causes the relay 68 (Fig. 1) to be shunted by a circuit extending from ground, through said interrupter brush and the interrupter, sequence switch contact H (5) to sequence switch contact J (5), where it joins the series circuit through the left winding of relay 74 and relay 68. The denergization of relay "68 removes the short circuit from relay 65.

Relay 65 is energized and in pulling up opens the shunt circuit extending to the armature of "relay 68 and completes through its left front contact a circuit to relay 66',

whereby it. will be. energized upon the next operation of relay 68.

W hen the switch reaches the first brush tripping position the interrupter brush 10 engages in-insulated segmentof the interrupter. Relay 68 again attracts its arma- .up until relay 68 deenergizes when the in terrupter brush 10 engages the second conducting segment of the interrupter 80, which occurs the next instant.

As we assumed that subscriber at substation S has-removed his receiver from the hook and that line relay 69 is in its energized condition, upon the energization of relay 65' a circuit will be completed from ground, througharmature and front contact of relay 69, conductor 71, armature and front contact of relay 65, and left winding of relay 67, to grounded battery. The conductor 71 and similar conductors at the other groups are eachmultipled to the front contacts of all the line relays in their respectivegroups. Relay 67 is energized and interrupts the series holding circuit through left winding of relay 7i and relay 68. Now, when the switch'reaches the second brush semoves on to the next insulating segment of -interrupter 80. Tliis'interrupts the other branch of the holding'eircuit of relay Ti which falls of? and completes through sequence switch contact B (5) a circuit for sequence switch motor magnet 76, and the sequence switch moves to position 6. In position 6 a circuit for the trip magnet 26is completed from battery, through conducting strip 79, brush 51, winding of magnet 24, brush 54 and the contact engaged thereby to ground through sequence switch contact D (6).

It will now be clear that due to the operation of interrupter 80 and brush 1O .suc-

cessive pairs of relays 65, 66 will be energized and locked up as the switch passes .through the corresponding brush selecting positions When the relay 65 associated with the group of a calling line pulls-up, it causes the cutoff relay 67 to operate and interrupt one branch of the holding circuit of relay 74. Now when the brush 10 passes on to the next insulating segment the other i branch of the holding circuit for relay 74 is interrupted, the relay falls off and drives 45- the sequence switch to brush tripping position. I a i The magnet 26 attracts its armature which engages the end of link 14, causing it to rock outwardly, and through the medium of strap 14% to rotate the trip rod 13. This causes the i elease of the second brushset from the'bottom. Had the calling substaswitch contact G (6). Relay 7 l through its right armature and contact B (6) completes a circuit for motor magnet 76 which moves the switch into position 7. In position 7, the previously traced cir cuit for up-drive clutch magnet 26% is again completed, and the shaft 1 moves upwardly causing the brushes thereof to traverse the line terminal contacts of its respective section of the panel bank. During the travel of the switch from its brush tripping posi tion until the brushes engage the first set of contacts in the bank a holding circuit is pro vided from battery through left winding oi. relay 74, contact and left armature of said relay contact E (6 to 7), conducting segment 81, to ground through brush 9. i

In position 7, a test circuit is provided from grounded battery, through the left winding of relay 7%, its left contact and armature, sequence switch contact H (1"), the left brush of the switch to the contact engaged thereby. Unless the line which terminates at a set of contacts ci'igagcd by the brush is a seeking line, the contact engaged by the left brush Will e grounded. if the 'Relay 74L is therefor maintained energized until the switch brushes engage the contacts of the calling line. Ground potential will not be found upon thetest contact of a calling line as the line relay will be energized.

minals of a calling line relay 74 will be deenergized, interrupting the circuit of the clutch magnet 24 and coinpletingat its back contact and right armature a circuit through sequence switch contact B (7) and sequence switch motor magnet 76 to grounded battery. The sequence switch then moves into position 8. 7,

Should the calling subscriber replace his receiver on-the hook before the brushes have reached the terminals of his line, or for any other reason, should the test of the calling line fail to take place, the switch shaft will continue to be moved upwardly until the brush 11 engages the conducting segment 82, when a circuit will be completed through sequence switch contact K (7) for the motor magnet 76, which will move the se quence switch into position 8. In position 8 the power circuit will be interrupted at contact C and a circuit will bO'COlllplCted from grounded battery, tell tale signal con tact K (8), segment 82 and brush ll to ground. The operation of signal 82 will indicate the position of the switch to an ob server who canthen determine the cause of trouble. If, sequence contact K is arranged to be closed in positions 1 to 9 instead of l to 7 the signal will receive only a flash and the sequence switch will be carried directly to position 18 which as will hereinafter appear, is the return to normal position. I

Returning now to the point where the .Therefore when the switch reaches the terlull) p 9 next seto'l' contacts in the bank 57 by means naomeo switclrhas stopped on the contacts of the calling line, in position 8 a circuit is coming device may be equally as well employed/ The sequence switch remains in position 8 until the plug 84 is inserted in jack 85, when a circuit is completed from ground, through the right winding of relay 74,

sleeve contacts of the plug and jack, to

grounded battery. Relay H is energized. and completes through its front contact and contact B (8) an energizing circuit for se quence switch motor magnet ,76, which moves the sequence switch into position 9. In position 9 the talking strands of the trunk are completed from the line finder brushes to the jack bymeans of the sequence switch contacts E and F (9).

At the time the sequence switch passed into position 8, a circuit was completed from grounded battery through the winding of clutch magnet relay 86, brush 53, the contact engaged thereby to ground, through sequence switch contact-l) (8 to 18) to ground. Relay 8.6 is energized and completes a circuit from ground, through its armature and front contact, clutch magnet 21 to grounded battery. Magnet 21 is energized and by attracting its armature operatively engages the friction disk 24 with the power disk 15 and the friction disk 20 atthe end of the worm 16. This causes the common up drive mechanism to move out of association with the finder switch just actuated.

The sequence switch of any selector which is at this time in use will be in either position 1, if the switch isin its normal position, or will be in position 18 if it is awaiting return to normal. No sequence switch,

except the one with which the common mechanism is associated, can be in positions 2 to 8. g

As the worm 16 rotates, it moves the common mechanism away from association with the switch just actuated and into association with the next switch, its circuit controlling brushes 51 to 56 being caused to en age the next set of contacts in the bank 5 This may be the next set, either at the right or at the'left, depending upon in which half of the spiral the follower 19 is located.

e will now assume that the nextfinder switch-is an idle one, in which case the sequence switch thereof will be in position 1 and sequence switch contact D will be open. Rela'y'86 willbe maintained energized until the brushes are centrally positioned on the of the engagement of brush 52 with one of the grounded contacts 87. When, however, the common mechanism is centrally positioned before the idle switch the circuit of relay 86 will be interrupted. Relay 86 in retracting its armature will open the circuit for clutch magnet 21, stopping the actuating mechanism in association with this switch. Relay 86 in retractlng 1ts armature Wlll also complete a circuit from grounded battery, through the sequence switch motor magnet (corresponding to 76) of the selector switch with wh1ch the common mechanism 1s now assoc1ated. ThlS circuit may be traced from battery throughsaid motor magnet, sequence switch contact B (1), contact and brush 56 of the common mechanism to ground through the back contact and armature of relay 86. The sequence switch of the selected line 'finder will then movev into position 2, in which position we find it when the next call is initiated by a subscriber.

Now we will assume that the next switch with which the common actuating mechanism is associated is busy or is awaiting return to normal. In either case contact D (8 to 18) will be closed and relay 86 will be maintained energized by a circuit through brush 53 and said contact, thus causing the mechanism to move on to the next switch. Thus it will be seen that the common mechanism will stop in association only with a switch which is idle and is in its normal position.

completes a circuit through contact B (9) for sequence switch motor magnet 76, which causes it to move from position 9 directly to position 18 or return to normal position.

In position 18 sequence 'swi-tch contact L is closed. This grounds the common con; ductor 92. The common return to normal mechanism, except when in active service, will be associated with a line finder, the

sequence switch of which is in positions 1- to 17 That is, it will never remain inactive in association with a switch, the sequence switch of which is in position l8.which;is the return to normal position. 1

Assuming that the common mechanism'is nowassociated with the switch corresponding to the sequence switch having contact L. The sequence switch of'this switch will be somewhere from positions 1 to 17, and a circuit will be completed from ground iaa through sequence switch. contact L (18),

common conductor 92, sequence switch contact L (1 to 17), test contact and brush 60 in engagement therewith, clutch magnet remouse lay 88,- to grounded battery. RelaySS will operate and complete a circuit for magnet 32, which in pulling up will force the friction disk 31 into operative engagement with the power drum 29, and the friction disk 30 at the end of worm 28. The worm 28 will revolve, causing the common return mechanism to be shifted from switch to switch, Ground potential will be maintained upon the commonreturn mechanism test contacts otallswitches, except the one awaiting return to normal. This ground potential will be supplied through contacts L,L, etc.,

' of the several switches. Magnet 32 will be stop the mechanism in association with the desired line finder. The sequence switch of this line finderbeing in position 18, a circuit will be completed from ground, through sequence switch contact D (18), contact and brush 61, back contact of relay 88, release and down-drive magnet 37, through the .upper brush 58 and conducting segment engaged thereby to grounded battery. The holding pawl 33 will be retracted and the switch will be lowered by the action of the drum 5 on the bar 6. As the switch approaches its lowermost position, the interrupterbrush 11 will engage the conducting switch, positions for said switch correspondsegment '90, completing a circuit through sequence switch B (18) for the sequence switch motor magnet 76, which will drive it from position 18 to position 1. It is now in a position to be again selected by the com .mon up-drive mechanism.

What is claimed is 1. In a telephone system, telephone lines divided into groups, a series of relays, one being common to all the lines of each group, an automatic switch, means automatically actuated incident to taking one of said .lines or use for causing the movement of said ing tosaid line groups, means for actuating one of said relays as said switch moves to each group, position, and means for arrestin'g' the movement of said switch when'the relay associated with the group of the selected line is actuated.

2. In a telephone system, telephone lines ihaving terminals divided into groups, a series of relays, one being common to all the lines of each group, an automatic switch, means automatically actuated incident to taking one of said lines for use for causing the -mo\ 'ement of said. switch, group selecting positions for said switch corresponding to said line groups respectively, means for ac-' tuating one of said relays as said switch moves to each roup selecting position, and means for operatively associating said switch with the terminals of the group of the line taken when the relay corresponding to said group is actuated.

I 3. In a telephone system, telephone lines having terminals divided into groups, a series ot'pairs of relays, a pair being common to the lines of each group, an automatic switch, means automatically actuated when one of said lines is taken for use for causing the movement ofsaid switch, positions for said switch corresponding to said line groups respectively, means for actuating a pair of said relays as said switch moves to each position, and means for operatively associating said switch with the terminals of the group of the line taken when the last relay of the pair corresponding to saidgroup is actuated.

-fL. In a telephone system, telephone lines having terminals divided into groups, pairs of counting relays, a pair being common to the lines of each group, an automatic switch, means automatically actuated when one of said lines is taken for use for'causing the movement of said switch, normally inoperative multiple brushes on said switch, one for each group of terminals, brush selecting positions for said switch corresponding to said groups of terminals respectively, means for energizing and locking up a pair of said relays as said switch moves to each brush selecting position, and means ,ior operatively associating a brush with the terminals of the group of the line taken when the pair of relays corresponding to' said group is actuated.

5. In a telephone system, subscribers lines divided into groups, a series of relays, one being common to all the lines of each group, an automatic switch, means for causing the movement of said switch upon the initiation of a call on any of said lines, positions for said switch corresponding to said line groups, means for actuating one of said relays as said switch moves to each group position, and means for arresting the movement of said switch when the relay associated with the group of a calling line is actuated.

6. In a telephone systcm, subscribers lines having terminals divided into groups, a series of relays, one being cohnnonto all lines of each group, an automatic switch, means automatiirally actuated upon the initiation of a call on one of said lines for causing the movement of said switch, group solecting positions for said switch corresponding to said line groups respectively, means for actuating one of said relays as said switch moves to each group selecting 'the relay corresponding tov said group is actuated.

aomao ating said switch with the terminals of the group of the calling line when the relay corresponding to said group is actuated.

sponding to said line groups respectively,-

means for actuating one of said relays as said switch moves to each group of said selector positions, and means for opera 'tively associating said switch with the terminals ofthe group of the calling line when 8. In a telephone system, subscribers lines having terminals divided into groups, a series of pairs of relays, a pair being common to the lines of each group, an automatic switch, means automatically actuated upon the initiation of a call on one of said lines for causing the movement of said switch, positions for said switch corresponding to said line groups respectively, means for actuating a pair of said relays as said switch moves to each position, and means for operatively associating said switch with the terminals of the group of the calling line when the last relay of the pair corresponding to said group is actuated.

9. Ina telephone system, subscribers lines having terminals divided into groups, a se-' ries of counting relays, one being common to the lines of each group, an automatic switch, means automatically actuated upon the initiation of a call on one of said lines for causing the movement of said switch,

positions for said switch corresponding to said line groups respectively, means for energizing and locking up one of said relays as said switch moves to each positin, and means for operatively associating said switch with the terminals of the group of the calling line when the relay corresponding to said group is actuated.

10. In a telephone system, subscribers. lines having terminals divided into groups, a series of relays, one being common to the lines of each group, an automatic switch, means. automaticallyactuated upon the initiation of a call on one of said lines for causing themovement of said switch, group selecting positions for said switch corresponding to said groups of lines respectively,

means for energizing and locking up one of said relays as said switch moves to each selecting position, and means for operatively associating said, switch with the terminals of the group of the calling line when-the re lay corresponding to said group is actuated.

1. In a telephone system, subscribers 'meansautcmatically actuated inci l lines having terminals divided into groups, a series of relays, one being connnon tn the lines of each group, an automatic switch, ant to the lines switch,

initiation of a call on one oi sai causing the movement cit Salt brushes on said switch one for each group of terminals, brush selecting positions for said swltch corresponding to said groups or llllQS respectlvely, meanstoizactuatmg one of said relays as said switch moves to each brush selecting position, and means for o-peratively associating a brush with the terminals of the group of the calling line when the relay corresponding to said group is actuated.

12. In a telephone system, subscribers? lines having terminals divided into groups, pairs of counting relays, a pair being common to the lines of each group, an automatic switch, means automatically actuated incident to the initiation of a call on one of SiUCl lines for causing, the movement oi said switch, normally inoperative multiple brushes on said switch, one for each group of terminals, brush selecting positions for said switch corresponding to said groups of terminals respectively, means for energizing and locking up a pair of said relays as said switch moves to each brush selecting position, and means for operatively associating a brush with the terminals of the group of the calling line when'the pair of relays corresponding to said group is actuated.

13. In a telephone system, subscribers lines having terminals divided into groups, relays common to the lines of each group, an automatic switch, means automatically actuated incident to the initiation of a call on one of said lines for causing the movement of said switch, group selecting positions for said switch corresponding to said groups oflines respectively, means for energiaing and locking up one of said relays as said switch moves to each group selecting position, and means for operatively associating said switch with the terminals of the group of the calling line when the last relay of the pair corresponding to said group is actuated. I

' 14. In a telephone system, subscribers lines having ,terminals divided into groups, pairs of counting relays, a pair being common to the'lines of each group, an automatic switch, means automatically actuated incident to the initiation of a call on one of said lines for causing the movement of said switch, normally retracted multiple brushes on said switch, one for each group of terminals, brush selecting. positions for said switch corresponding to said brushes respectively, means for energizing. and looking up a pair of said relays "as said switch moves to each brush selecting position, and means for releasing the brush having access to the terminals (if-the group of the calling line when the last relay of a pair correspending to said group is actuated.

15. In a telephone system, a group of switches, common mechanism for control-.

ling the movement of said switches, an electro-magnet for operating said mechanism, acircuit for operating said electro-magnet, means for closing said circuit automatically actuated when said mechanism has finishedits operation with one of said switches for causing it to move" to and be operatively associated with the next idle switch of said group and means for opening said circuit when said mechanism is associated with said idle switch.

'16. In a. telephone system, a group of switches, common mechanism for control.- ling the movement of said switches to their operative positions, .an electro-magnet for operating said mechanism, a circuit for operating said electro-magnet, means for closing said circuit automatically actuated when said mechanism has finished its operation with one of said switches for causing it to move to and be operatively associated with ,the next idle switch of said group and means for opening said circuit when said mechanism isassociated with said idle switch.

- group of lines, a plurality of switches, any

one of which may operatively engage any of said llnes, common operatlng mechanism for said switches, means actuated upon the initiation of a call on. any one of. said lines for causing a selected switch to move to and associate itself with the terminals of said line, an elcctro-magnet for operating said mechanism to move it to the next idle switch of said group, a circuit for said electromagnet, means to close said circuit when said circuit switch has been associated with the terminals of said line, and means to open said circuit when said mechanism has been associated with the said next idle switch.

19. In a telephone exchange system, a

plurality of subscribers" lines divided into groups, groups of terminals corresponding to said groups of lines respectively, a plurality of switches, normally inoperative multiple brushes on each of said switches, one being adapted to traverse each of said groups of terminals, :1 common operating mechanism for said switches, means automatically actuated upon the initiation of a, call on one of said lines for causing the release of the brush having access to the-group of the calling line and for causing the movement of said brush to the terminals of said line, and means thereupon automatically actuated for causing said common mechanism to be associated with the next idle switch of the group, sald last named means comprising an electro-magnet for operatmg .said mechanism, and a circuit for said electro-magnet closed on association of the circuit switch with the terminal of said line andopened when said mechanism has moved to said next idle switch.

In witness whereof, I hereunto subscribe my name this sixth day :of March, A. D.

ALFRED H. DYSON.

, Witnesses:

E. EDLER, K. STAHL.

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