Historical Document · 1892
US 486,909 Automatic Telephone or Other Electrical Exchange
Strowger's improved exchange patent (vertical-and-rotary switch).
Historical Document · 1892
Strowger's improved exchange patent (vertical-and-rotary switch).
(No Model.) 4 Sheets—-Sheet 1. A. B. STROWGER. AUTOMATIC TELEPHONE OR OTHER’ ELEGTEIGAL EXCHANGE. No. 486,909. Patented Nov. 29, 1892. Z el Fig.1 \A/ITNEEEEE: ‘ - . : . ~ _ I . NVENTEI “L M Maw” : m 0 M0dm 4 S h e e +.u F S h e 6 LL 2 A.” B. S T R O W G E R AUTOMATIC TELEPHONE OR OTHER ELECTRICAL EXCHANGE. No. 486,909. mmmm bHLHIH Hilll Patented Nov. 29, 1892.. (No Model.) .4 ShBB1JS—-Sheet 3. A. B. STROWGER. AUTOMATIC TELEPHONE OR OTHER ELECTRICAL EXCHANGE. No. 486,909. Patented Nov. 29, 1892.7 2 / 2 w \\\\\\\\\\\\\\\\\\\\\\ " \\\\\\' \\\\\\\\\\\&\\\\\\\\\\\\\ \\" \ r Fag 19 I I lmnunliwwa " l l n4: uomns Pawns co. mo‘raumm. WAsmNuToNA D. c . s l l (No Model.) 4 Sheets—Sheet 4. A. B. STROWGER. AUTOMATIC TELEPHONE OR OTHER ELECTRICAL EXCHANGE. No. 486,909. ' Patented Nov. 29, 1892. Fig.21 . \ H926" Fill-25- Fig.26, Fig-2'7. Fig. 28 . WITNESSES! ' INVENTSRL 54M 1213M UNITED STATES PATENT i OFFICE. ALMON B. STROWGER, OFCHIOAGO, ILLINOIS, ASSIGNOR TO THE STROWGER AUTOMATIC TELEPHONE EXCHANGE, OF SAME PLACE. AUTOMATIC TELEPHONE OR OTHER ELECTRICAL EXCHANGE. SPECIFICATION forming part of Letters Patent No. 486,909, dated November 29, 1892. Application ?led February 19, 1892- Serial No. 422,162. (No model.) T0 on” whom, it may concern: exchange is connected electrically with every Be it known that I, ALMoN B. STROWGER, a other exchange at the central station for tele citizen of the United States, residing at Chi- phonic purposes. cago, in the county of Cook and State of IlliMy new system of electrical exchange is 55 5 nois, have invented a new and useful Auto- illustrated in the accompanying drawings, in matic Telephone or other Electrical Exchange, which—— of which the following is a speci?cation. - Figure l is a front elevation of the opera My invention relates tovmeans for switch- tive mechanism with the switch-table and ing a telephone, telegraph, or any other elec- part of the top of the base, shown in vertical 50 IO trical instrument into electrical connection section. Fig. 2 is a side elevation at a right with anyother electricalinstrnment of agiven angle to Fig. 1,of the mechanism directly con system, as will be hereinafter explained. nected to the main spindle, the switch-table The particular object is to provide means being in vertical section. Fig.3 shows three whereby a person at one station may make views of the main spindle, the last viewat the 65 [5 connection with any other station in the sys- right having a portion of the top and bottom tem by the aid of electrical appliances with- ends broken away to show longitudinal and ' out the assistance of an operator at the cen-. transverse holes. Fig. 4 is a side elevation of tral station, and a further object is to provide. a fusee which is secured to the main spindle. means for the purpose of a very reliable na- Fig. 5 is a plan view of Fig. 4. Fig. 6 shows 70 2o ture, so as to adapt this system of exchange a thrust-rod, which operates within the main to general use. spindle, as will be described. Fig. 7 is aplan In describing my new system of exchange view of the switch-table, together with sev I will con?ne myself to its application for eral other parts, the top of the base broken telephonic purposes; but it can be applied 'away. Fig.8is a portion of switch-table and 75 25 equally as well to changing the electrical con- base of the instrument, showing a means for nections for telegraph. and other similar in- adjusting the position of the switch-table. strnments, dynamos, or any kind of electrical Fig. 9 is a view looking upward on line 9 9 of appliances where changes in connections are Fig. 1, showing mechanism for rotating the For the pur- main spindle in one direction and which will 80 3o pose of illustrationl will term the place where each telephone is located a “sub-station ” and the exchange mechanism, located at some distance from the telephones, the “central station.” The sub-stations are each connected made from a distant station. be fully explained; Fig. 10, a partial view of central portion of Fig. 9, showing method of withholding pawls from ratchet-wheels; Fig. 1l,a view similar to Fig. 10,but showing com bined ratchet-wheel, pawl,and stopin action. ‘85 35 . with the central station by means of two wires Fig. 12 shows respectively side and topvliews: in the herein-described system of mechanism, of spring-arms for main spindle, one of which one of the wires serving for telephonic and arms supports contact-head shown in Fig.13 the other for switching purposes. At the respectively in side and end views; Fig. 14, sub-station in addition to the telephone there an elbow-lever for actuating contact - head; 90 40 are keys servingto control currents of electric- Fig. 15, a section of step and lower end of hol . ‘ ity, which operate the mechanism at the central station. For the sake of brevity I will term the system of mechanism at the central station, which can be operated by a person at 45 a sub-station, an “exchange.” At the central station there are as many exchanges as there low portion of main spindle,showingball-bear ing; Fig. 16, respectively elevation and ver tical section of step-bearing for lower end of main spindle; Fig. 17, respectively top, side, 95 and end views of adjustable stop for main spin dle; Fig. 18, side and plan views of combined are telephones or sub-stations, so that each ‘telephone is intimately connected to a particular exchange by means of the two wires 50 above mentioned, which exchange cannot be pawl and armature, the pawl engaging with the teeth of the main ratchet-wheel and serv ing as a backstop for main spindle; Fig. 19, I00 respectively side and plan views of bifurcated operated from any other telephone, but each lever and armature for imparting alongitudi 486,909 10 nal motion to the main spindle; Fig. 20, a mit rod 21 to rotate. This rack 22 is ?tted to front elevation of the Strowger central sta slide vertically in side and rear guide 23. tion line-wire switch, whose mechanism is There is a screw 24 under the end of rack 22, 70 subdivided in an application for a patent of as shown, by means of which the distance of the United States ?led December 24, 1891, Se the downward movement of the rack 22 can rial No. 416,023. Figs. 21, 22, and 23 and be adjusted, the rack being always urged Figs. 28, 29, and 30 aretelephones and switches downward by the action of spring 25 at arms for two separate sub-stations. Figs. 24 and 25 and 26 and 27, respectively, show two ex 11 and 12, pulling radially inward upon con 75 tact-head 111, which by the connection of el changes at the central station, there being one exchange at the central station for each of the sub-stations, if desired. Similar ?gures and letters refer to like parts throughout- the several views. 1 is the base upon which most of the oper bow-lever 17 to 20 the short arm 20 of this le ver presses downward against thrust‘rod 21. ative parts composing the central exchange are mounted. 2 is the top of the base, which has a posi~ tion at a right angle to 1. Figs. 2, 9, 10, and 20 11 show a portion 2’ of top 2, which hangs down from the front edge of the top, but is broken away in Fig. 1 in order to show the operative mechanism attached to the upper portion of base 1. One of the most important parts of the cen 25 tral exchange is the switch-table 3, which in this instance consists of an annular shaped It will be noticed that spring 25 passes di rectly through spindle 6. The construction of the step 7 is shown in section, Figs. 15 and 16. The center of the step is perforated at 26 to permit the passage of thrust-rod 21 downward from spindle 6. At 6’ are balls ?tted under thelowerend of spin 85 dle 6 to diminish friction. Projections 27 at the bottom of step 7 are loosely ?tted to holes in the projecting lug 8, so as to prevent the step; from rotation with spindle 6, but permit the step and spindle to be moved vertically a short distance. The lugs 27 project below the lower side of lug 8, and bearing against their lower end are the ends of the bifurcated le-i ver 28, Figs. 1 and 2, which lever is pivoted piece of insulating material, having a neck 4, at the center of its length to a lug ?rmly sc 95 which elevates the table above top 2 of base cured to base 1, forming a part of the guide 1. The switch-table is adjustably attached to top 2. Around the switch - table, Fig. 2, are annular rows of wires 5, whose heads project 23 of rack 22. There is an armature 29 at.’ tached to the outer end of lever 28, and be low and attached to. an outwardly-projecting through table 3, as shown, a portion of each bracket 30 from base 1 is an electro-magnet rowindicated by dotted line, thelower ends of 31, by which armature 29 and lever 28 are 0p 35 the wires projecting outward from under the projecting outer portions of table 3 to a suffi cient distance to permitan easy attachment to them of certain wires, which will be described. Centrally located at the center of the diame ter of the circular rows of wire heads 5 is the main spindle 6, whose lower end has a pivotal ball-bearing in a step 7, which step is sup ported by means of a projecting lug 8 from base 1. The upper end of spindle 6 is pivoted erated. ‘ At 32, Figs. 1, 2, 9, 10, and 11, is a ratchet wheel having over one hundred teeth, and at is a lever, which is pivoted at 33', the le :03 ver having a pawl 3-1 at the outer end of its long arm to engage the teeth of wheel 32. An electro-magnet 35 is secured to the base 1, and the armature 36 of this magnet is ac cured to magnet 35. Lever 33, Fig. 9, has a top screw 37 to limit its motion. 45 upon the lower end of a screw 9, which screw At 3.8 is a ratchet-wheel having one tooth is held in central position by means of the to every ten teeth on ratchet-wheel 32, and a cross-brace 10, the feet of the brace being se lever pivoted at 40, which lever has a pawl cured to the switch-table 3 near the outer edge 43 at the end of its long arm contacting with thereof. Main spindle 6 is pivoted so as to be the teeth of and for operating ratchet-wheel 11; capable of a small amount of longitudinal mo' 38, and there is an electro-magnet 41, having tion, which will again be referred to. Near an armature 42, which is attached to lever 39. the top of the main spindle 6 are secured to Secured to ratchet-wheel 32 is a pin 32’, which a central base spring-arms 11 and 12. Con operates as a stop by contacting an arm 44 of structed to slide upon arm 12 is a contact an adjustable slide 45, this slide being mov 55 head 14, which is provided with a contact ably attached to the front of base 1. point 15 and an arm 16 to connect the head Figs. 1 and 9 show a magnet 46, which is with the long arm 17 of an elbow-lever, which attached to a base 47, the base having an arm‘ lever is pivoted to a projecting lug 19 of main 48, to whose top end is pivotally secured the spindle o‘. The short arm 20 of the elbow-le combined pawl 49 and armature 49’, Fig. 18, ver projects inward, and its end is pivotally this armature being operated by magnet 46, ‘connected with the top of a short pitman and the pawl engages with the teeth of ratchet? 18, the lower end of the pitman being piv wheel 32, serving as a stop, which stop is re otally connected to the top of thrust-rod 21, leased from contact with the teeth of wheel which rod passes down through the center 32 by the attraction of magnet 46 for arma» 65 and out at the lower end of main spindle 6, ture 4:9’, as will be further explained. The where the lower end of rod 21 is pivoted in base 47, together with all the attached parts, the top of a short piece of cog-rack 22 to per is adjustable, in order that the contact end of 486,909 pawl 49 can be moved to stop ratchet-whee 32 and all the parts attached to spindle 6 in the exact position necessary. Screws 50 and 51 are operated to adjust pawl 49 to the proper a 74, thence by wire F through electro-magnet 31 and to the ground-binder 75. Wire E con~ ducts current from binder 80 with electro-mag 70 net 62, thence by wire E to binder 74, thence by wire F through electro-magnet 31, thence position. In Figs. 1 and 2 is seen a ratchet-wheel 52, by Wire F to ground-binder 75. By this ar which is pivoted to revolve on a stationary rangement the out-current wires from mag pin 53, the pin having one end ?rmly secured nets 35, 41, 46, 55, and 62 allconneot with 75 in the end of lug 53’ of base 1, Fig. 2. Firm binder 74, thence by wire F through magnet ly secured to the front side of ratchet-wheel 31, which magnet is thus always energized by 52 and revolving therewith is a small pinion every current of electricity which passes 54, which engages with the cogs of rack 22. through the other magnets shown in Fig. 1 There is an electro-magnet 55 secured to a for the purpose as will be described herein bracket 56 of base 1. The armature 57 of after. The construction and relation of the switch magnet 55 forms one piece with pawl 58, and is pivoted at 59 to a projecting lug 60 of base table is shown in Figs. 1, 2, 7, and 8. In this 1. Pawl 58 is held in contact with ratchet instance it is intended to perforate the table -wheel 52 by spring 61, and the pawl is re with ten concentric rows of holes, as shown 85 ' leased from contact with the ratchet-wheel by by the dots 5 and dotted lines in Fig. 7, each 20 the attraction of magnet 55 for armature 57. row to have one hundred holes, making a total Ratchet-wheel 52 is revolved by the action of one thousand for the entire table, and each of magnet 62 attracting armature 63 of lever of these holes is to form the place of attach 64, which lever is pivoted at 65. At the end ment of a wire, the ends of the wires prefer of 64 there is pivoted a pawl 66, which en ably projecting slightly above the top of the 25 gages the teeth of ratchet-wheel 52, and the table, the other end of the wires projecting length of the lever is such that one downward radially outward all around under the table stroke causes pawl 66 to revolve wheel 52 a to a distance sufficient to be easily connected distance equal to the pitch of one tooth to other wires of the exchange system. For 95 thereof. Pawl 66 is always out of engage convenience the wires of the ?rst row next ment with ratchet-wheel 52 when lever 64 is the center of the table will be numbered from at the upward limit of its stroke by a small “1 ” up to “ 100,”and the next row outward be forward projection 67 of the pawl striking numbered from “100” to “200,” and so on,the against adjusting-screw'GS, for the purpose last row being “900’7 to “1,000,” and any con as will appear hereinafter. There is a screw venient number of rows can be added, if nec 35 69, which passes through a stationary lug 70, essary, or a greater number than one hundred and this screw holds pawl 66 in close engage ment with the teeth of ratchet-wheel 52 when wires can be placed in each of the rows to suit the requirements of practice. When spindle 6 is in the position shown in [05 the pawl is at the termination of its down? ward stroke, which combination of parts Fig. 1, with pin 32' in contact with adjustable serves as a stop mechanism to limit ratchet stop-arm 44, the contact-point 15 of head 14 will rest on the metal plate 81, which is sunk with its upper face flush with the top surface of 71, Figs. 1, 2, 4, and 5, is a fusee, which is switch-table 3, Fig. 7. In this position con IIO ?rmly secured to main spindle 6. To the tact-head 14 will have no electrical connec 45 fusee 71 is attached one end of a chain 72, the tion with wires 5. For convenience of de other end of the chain being attached to a scriptionl will term plate 81 the “zero-plate,” spring 73. This fusee, chain,‘and spring mech since it forms the starting-place from which anism is for revolving shaft 6 against the ac to ?nd any numbered wire on switch-table 3. wheel 52 from turning more than one notch for every downward stroke of lever 64. tion of pawls 34 and 43, the fusee equalizing Spindle 6, with its several attached parts, is held at the start or zero positionwith pin 32’ the pull of spring 73. At 77, 78, 79, and 80 are binders, to which against stop-arm 44 by the tension of spring are attached wires which electrically connect them with the several magnets, as follows: Wire B connects binder 77 with release elec 55 tro-magnets 46 and 55, the same current of 73, whose attached chain 72 is secured to fusee 71 at its largest diameter, so that when the [20 spring is contracted it will have the advan tage of greater leverage to turn spindle 6 ; but operating them simultaneously and the same current passing out of magnet 55 through wire 13 into binder 74, thence by wire F through electro-magnet 31, thence through wire F to binder 75, which is connected with the ground. length and its tension greatest, chain 72 exerts a pull at thesmallest diameterof the fusee, the 125 action of spring 73 turning arm 12 with head 14 in the direction of arrow G, Fig. 7. VVireO conducts current from binder 78 with magnet 35 by way of wire 0, binder 78, pawl electricity passing through both magnets and when the spring is pulled out to its greatest When an electric current is sent through electro-magnet 35,thence by wire 0 to binder 34 engages ratchet-wheel 32, which is turned 74, thence by wire F through electro-magnet the distance of the pitch of one tooth, which 31, thence by wire F to ground-binder 75. revolves spindle 6 and arm 12 with contact 65 Wire D conducts current from binder 79 with head from the zero-plate 81 in the direction electro-magnet 41, thence by wire D to hinder of arrow H,_Fig. 7, so that point 15 of head 486,909 14 will contact the ?rst wire 5 in ?rst row next the center of switch-table, when, if the current is broken in magnet 35, spring‘ 82, Fig. 9, will lift lever 33 and pawl 34, the end (ll of the pawl falling into the nexthigher notch in wheel 32, when, if another current of elec tricity is sent through magnet 35, contact head 14 will simultaneously be moved forward, with its contact-point 15 resting upon wire tion shown in the drawings, the projection 67 con-tacting-screw-stop 68 and turning the pawl on its pivot and force it out clear of ratchet-wheel 52, the ratchet-wheel being held in the changed position by pawl 58. By the partial revolution of wheel 52 rack 22 is caused to. ascend by the action of pinion 54, which is attached to wheel 52. The upward 75 movement of rack 22 causes the attached No. 2 in the ?rst row, and so on, until by the thrust-rod 21 also‘ to rise, and the upper and successive impulses by currents sent through of the thrust-rod being connected to the short‘ magnet 35, the contact-head 14 will be carried arm of elbow-lever 20. 17, causes the long arm around and successively contact the end of 20 of this lever, together with the attached every wire in the ?rst row until the pin 32' contact-head 14, to move outward from the will contact the opposite side of stop-arm 44, center of spindle 6 the distance for thepoint when, if required, the spindle 6, together with 15 of head 14 to contact the second row of contact-head 14, can be quickly revolved back wire ends of switch-table It is understood ward to the starting-place or zero-plate 81 by that this action takes placewhile the contact 85 sending a current of electricity into release head 14 is at, the zero-‘plate 81 and before 20 magnet 46 by wire 13, when armature 49" will shaft 6 is revolved to carry pin 32' fromstop be operated and disengage its pawl 49 from arm 44. It is obvious that every time a cur rent is passed through magnet 62; contaek ‘wheel 32, when spindle 6, being free to re volve, will quickly return because of the pull of spring 73 on fusee 71 until pin 32’ contacts 25 with adjustable st0p~arin 44, when contact point 15 will again he at the zero-plate 81. In order to facilitate the operation of this 5 from the next inner row, and so on, to any row ‘in table 3, when any certain wire in the, particular row desired can be contacted by ~ exchange, we have introduced a ratchet-wheel point 15 of head 14 by the means described head 14 will be moved outward from thocen ter of shaft 6 the distance of one row of wires 1 38, having ten teeth, which wheel is also ?rmly for the ?rst row. W hen it is desired to return secured to spindle 6 and is operated by an contact-head 14 to the zero-plate in the ?rst rum‘ ‘ electro-magnet 41, having an armature 42, at of wires on switch-table 3, a current; of clear tached to a lever 39, which lever has a pawl 43 to engage the teeth of the ratchet-wheel. Now tricity is. sent into magnet 46 through wire B,‘ which releases pawl 49,and the same current itis obvious that by sending a current through after passing through magnet 46 is led into 35 wire D into magnet 41 spindle 6 would be magnet 55 by wire B, when armature 57“ is‘ turned over as much space by one downward operated, causing the release of pawl58 from thrust of pawl 43, turning wheel 38 the dis‘ ratchet-wheel 52, when by the gravity of rack tance of the pitch of one of its teeth as'would 22 and thrust-rod 21 and the tension of spring be done by ten separate thrusts of pawl 34 25,0peratingto pull contact-head 14 and arm 17 on wheel 32, so that should it be necessary'to of elbow-lever 17 20 inward and shortarm?O. have contact-point 15 connect with wire 42 of downward with thrust-rod 21, rack 22 falls, the switch-table 3 four separate and distinct so that its lower end rests upon the topic! currents of electricity being sent through adjusting-screw 24, and in the meantime, magnet 35, when ratchet-wheel 32 will be pawl 49 being released, shaft 6 is carried. 45 turned through the distance of the pitch of around by the pull of spring 73 on fusee 71 two teeth, when contact-point 15 will rest until pin 32’ contacts with adjustable stop upon the end of wire No. 42. I have new explained the means for caus ing contact-head 14 to move to and contact its. point 15 with the end of every wire in the ‘ ?rst row of switch-table 3, and will now ex arm 44, when the point 15 of, contact-head 14 will rest on zero-plate 81, near the end‘ of i the first row of wire heads 5. In the operation of the several parts herein described, if shaft 6 should have no vertical plain the means by which contact-head 14 is longitudinal motion, the point 15 of contact carried to the second, third, or other rows of head 14 would cause considerable friction by wires exterior to row No. 1. lVhen a cur its contacting the top of switch-table 3 while 55 rent of electricity is sent through magnet 62, arm 12 is being carried around to some desig armature 63, together with lever 64 and pawl nated wire end 5, or when the pawls 49 and 66, is operated. Pawl 66, by the downward 58 are released and spindle 6 is revolving, motion of lever 64, moves out of contact with backward by the action of spring 73, there‘ screw 67, and the lever end of the pawl con would necessarily be required a much stronger tacts with the teeth of ratchehwheel 52, and spring 73 to give the necessary power for this the continued downward motion of the pawl duty. Therefore to obviate this objection‘I turns wheel 52 the distance of the pitch of provide means to lift head 14 clear ofswitclr one tooth thereof. When in the meantime table 3 by connecting the out-current wires stop~pawl 58 has engaged a tooth of wheel 52, from magnets 35, 41, 46, 55, and 62 to binder 65 so that when the current of electricity ceases 74, and then connect binder 74 by wire F to in magnet 62 spring 83 raises the long arm of magnet 31, thence by wire F to ground binder “ lever 64, together with pawl 66, to the posi 75, as hereinbefore stated, ‘so that, simultane 486,909 ‘ 3' 5 ously with every horizontal movement of con “11.,” “T.,” and “Hm,” which project from the tact-head 14, magnet 31, through the medium dial, connect with a pair of the metal heads. > of bifurcated lever 28, lifts step 7 from bracket Figs. 23 and 30 show a dial with ?ve insu 8, togetherwith spindle 6, spring-arm 12, and lated-metal heads all connected together by the attached head 14, the distance lifted being wire, (shown in dotted lines,) and these heads small and simultaneous with the action of are also connected to a battery 90 by a wire any of the other magnets. Head 14 is moved 91. Themetal heads are marked “R,” “Tel.,” to any position when spindle 6 is moving for “11.,” “T.,” and “Hu.” Key 92 can be revolved 75 ward or backward without point 15 contacting entirely around the dial and successively con IO with any part of table 3 or with wires 5 until tact each of the metal heads. The hand spindle 6 has ceased revolving, thus making marked “92” is connected byvwire 93 to mag it possible to construct a switch-table 3 with net 85 at the central station. many thousands of wires 5, anyone of which Figs. 22 and 29 show keys which have an So is within easy reach of contact-head 14 without insulated base 94. A metal spring 95 con requiring more power to carry contact-head tacts 96, which is connected with batterv 90. around outer than the inner rows of wires of Binder 97 is connected with spring 95. Metal switch-table 3. stop and binder 98 connects with spring 95 In Figs. 9 and 10 it will be noticed that when spring is in position shown in draw 85 pawls 34 and 43 are always lifted from en ings. WVire 99 from telephone connects with 20 gagement with the ratchet-wheels when the binder 98,and wire 100 connects binder 97 to pawls are not in action, the ratchet-wheels and one of the wires 5 of the switch~table of ex ~ shaft 6 being held from turning backward change, Fig. 26, there being also a wire 88 . through the action of spring 73 on fusee 71 by connecting wire lOOwith the switch-hand 86 9O pawl 49, which is one of the release-pawls. of Fig. 25, as plainly shown in Fig. 20. The 25 There is a projection 84 near the pivotal cen connection of sub-station 531, Sheet 4, with ter of both pawls 34 and 43, which projection the central station is similar to that above contacts with screws 85, passing through a por described for sub-station 12. tion 2’ of the top 2. Stop-screws 86 are also It will be noted that a current of electricity 95 provided, which contact the ends of these can pass from telephone 12- through wire 99 pawls to serve as stops for the ratchet-wheels to hinder 98, thence through spring-key 95 in the same manner as has been described for to hinder 97, thence by wire 100 to switch pawl 66, which is operated by magnet 62. In tabic 3 of Fig. 26, where it can be secured to order. to insure perfect central contact of con one of the wires 5, where it will be known as I00 tact-point 15 with the ends of wire 5 on switch “wire 12.” The same connections are made 35 table 3, this switch-table is secured to the top from telephone 531, Fig.28, so that its wire is 2 of base 1, so that it can be moved slightly connected to table 3 of exchange, Fig. 24. concentric with shaft 6. Figs. 1 and 8 show a Wires 88 having electrical connection with lug a, which projects from the neck 4 of the wire 100 a current can pass from battery 90 switch-table, and at either side are lugs b and to binder 96, thence by way of key 95, when c, which are part of the top 2. Adjusting the key contacts 96, to binder 97, thence by screws (1 and e of lugs band 0 contact at each wire 100 and then wire 88 to connection 89 side of lug a and serve as means for quickly and out hand 86 to any of the wires “R,” and accurately adj usting the switch-table and “Tel.,’7 “U.” “T.," or “I-Iu.,” according to the ITO of retainingit securely in the position desired. contact-head of dial 87, which hand 86 may 45 Sheet 4 of the drawings shows the wire con rest upon. Wires “R,” “TeL,” “U.” “T.,” and . nections from two sub-stations to a central sta “Hu.,” Fig. 20, are connected, respectively, tion, and the application of the Strowger in with wires shown at right-hand end of Fig. 1., dicating-switch. Figs. 21, 22, and 23 I will which are designated by similar letters, and I15 assume is sub-station No. 12, and Figs. 28, 29, communicate with the magnets, respectively, and 30 sub-stations N o. 531, the number of the for “ release,” “. telephone,” “units,” “tens,” ‘station being shown on the telephone-box, as usual. Figs. 24 and 25 is the exchange be longing to telephone 12, and Figs. 26 and 27 the exchange for telephone No. 531. 55 It will be noticed that Fig. 20, Sheet 3, shows an enlarged view of Figs. 25 and 27, Sheet 4, this being the central-station portion of the Strowger automatic switch, which, in short, consists of an electro-magnet 85,which through a lever, pawl, and ratchet moves a hand 86 around a dial 87 in direction of ar row and connects, successively,one at a time, ten insulated-metal heads with a wire 86, which has a spring connection 89 with the 65 center of motion of hand 86. The heads dia-_ .metrically opposite on dial 87 are connected together. and “ hundreds.” These wire connections are plainly shown by Figs. 24 and 25. , The drawings on Sheet 4 plainly show that I20 since there is an unbroken connection between No. 531 and the switch-table 3, Fig. 24, of tele phone 12, a person turning the contact-head 14 of exchange, Fig. 24, around to No. 531 could ring up telephone 531 from telephone :25 12; but, to particularly explain, should a per son at telephone 12, Fig. 21, desire to com municate with a person at telephone 531, Fig. 28, key 92, Fig. 23, would be turned in the direction of the arrow from contact-head “ R,” or “release,” to contact-head “Hm,” or “hun dreds,” where an electric current will pass from battery 90 through wire 91, thence The wires marked “R,” “Tel,” through contact-head “Hu.” key 92, wire 93, 486,909 and into magnet 85 of the auxiliary switch, to, said switch having its contact-head mov Fig. 25, which will cause hand 86 of the switch able vertically, radially, and laterally, where to move to the right of “R,” which head con by it occupies a plane above the ends of the 70 nects with “Hu.” on the opposite side of the wires when moving and occupies the plane of switch-dial. It now spring-key 95 be pressed the ends of the wires when at rest and may down to contact 96 an electric current from be moved from the end of one wire to any battery 90 will pass through the key, thence other wire without coming in contact with the through wire 100, then wire 88 to and through intermediate wires, substantially as setforth. 75 2. In an automatic electrical exchange, the connection 89, thence through hand 86, thence IO through wire “I-Iu.” into the exchange, Fig. combination, with wires the ends of which are 24‘, to energize the m agnet- which operates the arranged in concentric rows in a horizontal hundreds mechanism. Spring - key 95 is plane, of a switch movably secured at the axis pressed down four times, which sets the con of said rows, the contact-point of which switch tact-head 14 in the exchange out to the be is movable radially and annularly relatively ginning of the ?fth row of wires of the switch to the axis of the rows of wires and occupies table 3. The next number required is three a plane above the ends of the wires when mov tens, so that key 2 is moved in the direction ing and occupies the plane of the ends of the of the arrow to contact with the “' ‘.” or “tens” wires when at rest, substantially as set forth. 85 3. In an automatic electrical exchange, the contact-head, when simultaneously hand 86 at the exchange auxiliary switch will move combination, with a series of wires, of a switch one more space on dial S7 and make connec adapted to be placed in electrical connection tion with “T.” or the “tens” wire of the ex with any one of said wires and a pin con change, after which key {)5 is pressed down nected therewith and an adjustable slidepr0~ 90 three times, causing the main spindle 6 to vided with an arm for engaging said pin and for limiting the return movement of said switch after said connection has been made wanted is one or one unit, so the key 92 is and broken, substantially as set forth. 4. In an automatic electrical exchange, the 95 turned to contact the units-head, when hand 86, Fig. 20, makes connection with the units combination, with a series of wires, the ends 25 carry contact-head 14 around the switch~table to wire 30 in the ?fth row. The next number magnet in the exchange, when by pressing of which are arranged in concentric rows or down upon key 95 one time the required wire, circles, of a shaft journaled at the axis of the No. 531 is contacted by head 14 when key 92 is rows of wires, a switch secured thereto, the turned to contact-head “Tel.” or “telephone,” contact - point of which is movable radially 100 when hand 86 connects wires 100 and 88 with and annularly relatively to said shaft, a rod 35 wire “ 'l‘el.,” which connects at the extreme movable longitudinally to the axis of the shaft, top of the exchange to binder on main-spin connected with the contact- point of said dle pivot-screw 9, thence an electric current switch, and an adjustable stop at one end of can pass into the main spindle 6, spring-arm the rod for limiting the return movement of ms 12, contact-head 14, thence through wire No. the contact-point, substantially as set forth. 531 to and through spring-key, Fig.29, thence 5. In an automatic electrical exchange, the to telephone 531, when the signal~bells can be combination, with a series of wires, of a switch made to ring and the telephones operated as adapted to be placed in electrical connection ordinarily. Ii’, however,only units are wanted, with any one of said wires, the con tact-point of [10 as No. 9 of the ?rst row of wires, the switch which switch occupies a different plane when 45 95 is not operated as the key 92 passes the moving from what it does when at rest, and a . “II.” or “hundreds” contact-head nor as it series of magnets, one of which operates mech passes the “T.” or “tens” head, and conse anism for moving the contact~point from one quently the contact-head leis not moved out plane to the other and the remaining mag :15 ward on the arm 12. Hence when the key 92 reaches “U.” orthe “units” contact-head each downward pressure of the switch 95 will only cause the head 14 to move one step or wire around the ?rst row of wires, and when it has been pressed down nine times the head 14 will 55 be in contact with the end of line 9, which es tablishes communication with the d esired tele phone at the other sub-station. nets operate mechanism for moving the point in the diilferent planes, all of said magnets having a common ground-wire, the ?rst-incur tioned magnet being electrically connected‘ with each of the other magnets and with the I211 ground-wire, whereby the contact-point is al ways moved from one plane to the other whenever the switch is operated, substantially as set forth. It is obvious that an additional number of 6. In an automatic electrical exchange, the 125 telephone-exchanges can be connected in the ‘combination, with a series of wires, the ends 1 same manner, as is shown by Sheetlt of the of which are arranged in concentric rows or ‘ drawings. circles, of a switch movably secured at the Having thus described my invention, I center of said rows, the contact-point of which claim switch is movable radially and annularly rela :30 1. In an automatic electrical exchange, the tively to the axis of said rows, ratchet-wheels 65 combination, with a series of wires the ends for placing said switch in contact with any ‘ of which are arranged in a horizontal plane, one of the ends of said wires, an electrically operated lever for each wheel, one end 0! of a switch movably secured relatively there 486,909 which lever is provided with a pawl, and point of which rests upon and’ is movable to means for positively disconnecting said pawl ward and from said plate, substantially as set from its ratchet-wheel When at rest, substan forth. tially as set forth. 11. In an automatic electrical exchange, the 7. In an automatic electrical exchange, the combination, with a table having a series of combination, with a series of wires, the ends wires secured thereto, of a switch the contact— point of which is adapted to be placed in elec circles, of a switch movably secured at the trical connection with any one of said wires, 65 center of said rows, the contact-point of which said table being concentrically adjustable switch is movable radially and annularly rela relatively to the switch, substantially as set tively to the axis of said rows, ratchet-wheels forth. for placing said switch in contact with any 12. In an automatic electrical exchange, the one of the ends of said wires, an electrically combination of a series of wires the ends of operated lever for each wheel, one end of which are arranged in concentric rows or cir [5 which lever is provided with a pawl, and ad cles, a shaft journaled. at the center of said of which are arranged in concentric rows or justable mechanism for releasing said pawl rows, a switch secured to said shaft, means from its ratchet-wheel when at rest, substan for rotating the shaft in one direction, a fusee tially as set forth. on the said shaft for rotating the shaft in the 75 8. In an automatic electrical exchange, the opposite direction, and a spring - actuated combination, with a series of wires, the ends chain secured to and adapted to run on and of which are arranged in concentric rows or ‘off of said fusee substantially in a line with circles, of a switch movably securedat the the angle of the pitch of the spiral of said center of said rows, the contact-point of which ' fusee, substantially as set forth. So switch is movable radially and annularly rela 13. In an automatic electrical exchange, the 25 tively to the axis of said rows, ratchet-wheels combination of a series of wires arranged in for placing said switch in contact with the a horizontal plane and a contact-head mov ends of any one of said wires, an electrically able relatively thereto, a longitudinally-mov operated lever for each wheel, one end of able spindle or shaft for operating said head, 85 which lever is provided with a pawl, and a step for the reception of the lower end of means for limiting the forward movement of the spindle, provided with projections upon said pawl and for forcing ittoward the ratchet the bottom, a bracket or lug provided with wheel, whereby it acts as a stop for the perforations for the reception of the step, an ratchet-wheel at the end of the thrust or for armat.ure~lever, one end of which is bifurcated ward movement of the pawl, substantially as and engages with the ends of the projections upon the step below the bracket, and an elec 35 set forth. 9. In an automatic electrical exchange, the tro-magnet for operating the lever, substan combination, with a series of wires, the ends tially as set forth. of which are arranged in concentric rows or 14. In an automatic electrical exchange, the 95 circles, of a switch lnovably secured at the combination of a series of wire ends arranged center of said rows, the contact-point of which concentrically in a horizontal plane, a verti switch is movable radially and annularly rela cally-movable shaft or spindle at the center tively to the axis of said rows, ratchet-wheels of said ends, spring-arms secured to the up for placing said switch in contact with the per end of the spindle, a contact-head mov I00 ends of any one of said wires, an electrically ably secured to one of said arms,a spring se 45 operated lever for each wheel, one end of cured to the head at one end and to the outer which lever is provided with a pawl, and ad end of the other arm at the opposite end, and j ustable mechanism for limiting the forward means for rotating said spindle upon its axis movement of said pawl, substantially as set and moving the head upon said arm, su