Historical Document · 1899
US 638,249 Electrical Exchange
Keith/Erickson switch close to the modern step-by-step switch.
Historical Document · 1899
Keith/Erickson switch close to the modern step-by-step switch.
No. 638,249. Patented Dec. 5, 18991.‘ A. E. KEITH a4. & c. J. EBICKSON. ' ‘ ELECTRICAL EXCHANGE. (Application ?led Dec. 16, 1895.) (N0 ModeI.) Fig. 1. - 5 Sheets—$heet l. 63 Fig. 2. No. 638,249. > ' Patented Dec. 5, I899. A. E. KEITH & J. & C. J. ERICKSON. ELECTRICAL EXCHA'NGE. A (‘No Model.) Fig. 3-\ 44: ; 1' t‘ ( “mm r 13 man e ac .16,1s95.' ) 4? ' 5' Sheeis—Sheet 2. 3A7 No. 638,249. Patented Dec. 5, I899. A. E. KEITH &. J. &. C. J. ERIGKSON. ELECTRICAL EXCHANGE.‘ (Application ?led Dec. 16, 1896.) ' (N0 Model.)v 5 Sheets-Sheet 3. '31 alarm-m. E... 764122 9194..., gaffe/44a“. M “wwwr‘fw 15772“; 7, oTmuTHQ, WASHINGTON u g No. 638,249.‘ . ' Patented Dec. 5,1899. A. E. KEITH & J. & c. J. ERICKSON. ELECTRICAL-"EXCHANGE. . (No Model.) A Fig. 14. ‘ 1' t‘ ‘ ppm,“ ?l d D e "° ' \ > . 15, 1895. ) 5 Sheats-$heet 4. » Fig. 15. < / ' / 6&1 367 '74 1 Fig. 14-A4 \NITNESSES: ig. 15\A. We‘ lpNaylgoasy @M‘QZ T90: mm: mm: C0,. momma. wAsrlmumu. a. n. 2 _ No. 638,249. Patented Dec; 5, I899. A. E. KEITH &. J. & c. .1. EBICKSON. ELECTRICAL EXCHANGE. EAppIication ?led Dec. 16, 1895.) (No Model.) .5 Sheets-Sheet 5. 7, 367 6,1 / 295961 - Fig. 162» Fig. 17A- Fig. 18A. ‘ . ‘WITNESS-Es: ' ‘ U “ ‘ ' INVENTORS. MMéM, 5- M' nrrnn TATES PATEN FFICEt ALEXANDER E. KEITH, JOHN ERIOKSON, AND CHARLES J. ERIOKSON, OF CHICAGO, ILLINOIS, ASSIGNORS TO THE STROWGER AUTOMATIC TELE-' PHONE EXCHANGE, OF SAME PLACE.‘ ELECTRICAL EXCHANGE. SPECIFICATION forming part of Letters Patent No. 638,249, dated December 5, 1899. Application ?led December 16, 1895. Serial. No. 572,831. (N0 model.) To all whom it may concern: ' rivets or bolts which pass through a group Be it known that we, ALEXANDER E. KEITH,‘ of contact-points comprising a number of J OHN ERICKSON, and OHARLEs J. ERICKSON, curved insulating-pieces, shown in elevation citizens of the United States, residing at Chi and plan view in Fig. 7. Fig. 8 is a plan view cago, in the county of Cook and State of Illi of oneof the curved insulating-pieces shown 55 nois, have invented a new and useful Elec in Fig. '7 as it appears when attached to the trical Exchange, of which the following is a exchange, with the contact-points in position, speci?cation. , and one of the wipers for contacting the same attached to its shaft and in the normal posi tion. Figs. 8A and 8B are broken detail views eral novel features and modi?cations in the of the releasing mechanism, taken in two po‘ construction of the system of electrical ex sitions, and 8C is a detail view of the bent changes embodied in Letters Patent of the wire 48. Fig. 9 is a plan View of the main United States No. 540,168,‘ dated _May 28, shaft with ratchets through which the same Our invention relates to electrical ex IO changes; and our object is to introduce sev 1895, to Alexander E. KeithrFrank A. Lund= quist, John Erickson, and Charles J. Erick son, and also application for patent of the United States for electrical exchange, Serial is operated mounted thereon, an auxiliary 65 switch being also shown in position, together with three wipers, these several points being shown in the initial position. Fig. 9A is an ‘No. 556,229, ?led July 1'7, 1895, invented by» elevation the same as upper portion of Fig. 9, Almon B. Strowger, Frank- A. Lundquist,‘ but with. an auxiliary switch-arm in the po John Erickson, and Charles J. Erickson, our sition it occupies after six step-by-step r0 new improvements being described herein tary movements and after the main shaft has after and illustrated in the accompanying had the ?rst longitudinal step-by-step move drawings, in which—‘ ment. Fig. 9Bis asimilar elevation as shown Figure 1 is a front view, and Fig. 2 a side in Fig. 9, with the exception that the main 75 25 elevation, of an electrical exchange in the sus shaft has had ?ve longitudinal step-by-step pended normal position, in which is embodied movements upwardly and two step-by-step ro= the greater part of our improvements. Figs. ‘tary movements in the direction indicated by 3 and 3A are detached portions of the eleva ‘arrow A, the auxiliary switch having had two tion shown in Fig. 2,with several of the parts rotary step-by-step movements on the shaft 20 in a changed position to illustrate the man ner of operating an automatic cut-out for a and in the same direction, as indicated also by arrow A. Fig. 9C is a cross-section of the main secret system. shaft on line 3 4, Fig. 9, showing the auxiliary Figs. 4, 4“, and 4B show hori zontal sections of a portion of several ex switch and one of the wiper~arms of the main 35 changes on broken line 1 2, Fig. 1, looking switch in bottom elevation or when looking in 85 downwardly, and illustrate the curved po the direction indicated by arrow B. Fig. 9D is sition of the contact-points and the manner a horizontal section on line 5 6, Fig. 9A or Fig. of connecting the interconnecting wires of 9B, of the rotary ratchet-Wheel, with a plan of several exchanges, together with the relative the auxiliary-switch contact-point holder and position of the main switch arms or wipers at contact-arm in touch with the second contact 9O the normal position and when in touch with point. Fig. 10 is an elevation and a plan of the contact-points. Figs. 5 and 5A illustrate the half-twist of the interconnecting Wires at the point of connection with the contact 45 pieces and also show that the interconnect~ ing wires are stripped of the insulation where the cylindrical ratchet through which a lon gitudinal movement is imparted to the main shaft, there beinga projecting strip at one side of this ratchet for a purpose which is ex 95 plained hereinafter. Fig. 11 shows, respec they attach to the contact-strip hooks. Fig. tively, an elevation and a plan of the ratchet 6 shows, respectively, a front elevation and a through which a rotary movement is imparted plan of one of the curved metal strips which not only to the main shaft but to the arm of serve as end pieces for the attachment of the auxiliary switch. Fig. 12 shows, respec a 638,249 tively, a front and side elevation and a plan 15” normally in contact with a stop 19, pro of the holder,of insulating materiahinto which jecting from the contact-point holder 18. are secured the several contact points or pins There is a combined switch arm and coupler, . of the auxiliary switch, which holder is ?rmly in the form of the arm 20, which is firmly se 70 secured to the main shaft and partakes of all cured to and projects laterally from the lower its movements. Figs. 13, 13“, and 13B are ver end of the ratchet-wheel 15. Near the outer tical sections of the top plate of the frame of end of the arm 20 is a hole-20’, Figs. 90, 9D, the exchange and of the main shaft on broken and 11, which is at a distance from the cen IO line 7 7, Fig. 2, looking in the direction indi ter of shaft 9 so that as the ratchet 15 is re cated by arrow 0, to illustrate the action of a volved step by step against the tension of 75 spring cut-out which is fully described here inafter. Figs. 14, 14“, 15, and 15A are dia spring 15’ the arm 20 is carried around and at the termination of each step the hole 20’ grammatic views of two complete telephone registers with one of the contact-points 21, systems,with the exchanges therefor,the same capable of being connected, the parts being shown in the normal position, and, in order to avoid complication,the telephone,we will sup pose, is of the magneto variety and may there fore be used forboth transmitter and receiver. Figs. 16,16“,17, 17A, 18, and 18", respectively, represent three interconnected telephone sys tems and the exchanges therefor, the tele which are seen red in the insulating-holder 18. There are ten contact-points 21 shown in Figs. 2, 9B, and 12; but a greater or less num ber may be used, as may be necessary. Shaft 9is provided with a series of wipers insulatingly secured thereto, and in this in 85 stance all project from the same side of shaft 9. Only three wipers, 22, 22’, and 22", are shown, but more may be used in large cen phone set in Fig. 16A and the one in Fig. 18A tral stations, as may be required. Each being in speaking connnection through the wiper is connected independently by a wire to someone of the contact-points 21, and each 25 exchange in Fig. 16. The telephone set in Fig. 17A and the ex change therefor in Fig. 17 are ‘shown con nected to the exchanges in Figs. 16 and 18 to illustrate the action of an automatic secret service cut-out which each exchange is pro vided with and which effectually prevents two of the several wires has an insulating-cover ing, and for convenience the wires are formed into a cable, as shown in Figs. 1 and 2. The several exchanges of any given system 95 are each provided with one or more groups, such as 24 24' 24", of contact-points 25, Figs. persons whose telephones are connected being 1, 2, and 8. Each contact-point is insulated disturbed in conversation by a person at any from the other, and they are ranged in straight other telephone of a given system. vertical rows, but in concave horizontal rows, I00 Similar numerals indicate like parts as shown. Each group of contact-points is 35 throughout the several views. usually numbered 100 and secured between, In the drawings, 8 indicates the several plates of insulating material 25’, Fig. 7, and parts comprising the frame of the exchange, each group is secured upon vertical side rods to the upper part of which is pivotally mount~ 26 by means of the plates 26’, Fig. 6, as shown, ed the shaft 9, which is disposed vertically there being one wiper for each group. The and is operated longitudinally upward step first contact-point of each group of the top by step against gravity by means of a pawl or first series of groups is connected by an 10, engagingin theteeth of cylindrical ratchet interconnecting wire 27 with the ?rst con 11, the pawl 10 being attached to the free end tact-point of all the groups of that series, of an arm 10’, which is operated by virtue of and the second contact-point is connected by electromagnet 12. Shaft 9 is rotated step by a wire 27 with the second contact-point of all .step by virtue of magnet 13 through lever 14 the groups of that series, and wire 27'con and pawl 14’ engaging with ratchet-wheel 15, nects thethird contact-point, and so on, with all of which mechanism, including the de tents, is almost an exact duplicate of what is all the contact-points of each of the other se I15 ries of groups, as shown in Figs. 4, 4A, and 4B. At the lower end of the side rod 26 is se~ shown in application for patent Serial No. 556,229 and hereinbefore referred to, and cured an arm 28, to which is pivoted‘an arm therefore no particular description thereof is 29, whose other end is pivoted to the lower necessary. In the further description of our, end of a short piece of round rod 30, which I20 55 invention and in the claims we shall refer to projects upwardly within helical spring 31. The upper end of rod 30 is pointed and has nector,” and the two magnets 12 and 13 will abearing in the center of lower end of the be designated as “ motor- magnets.” The main shaft 9, which may turn thereon, but is ratchet-wheel 15, however, in this instance is held in contact therewith by the tension of I25 loosely mounted upon shaft 9 and. is held in spring 31, which has the lower end secured the initial position shown by helical spring to rod 30 and the upper end to the boss shown 15', which has one end attached to a down on the lower end of shaft 9, this spring also wardly-projecting arm 15” and the other end serving to turn shaft 9 backwardly to the to the boss 17 of the auxiliary-switch con normal position after it has been revolved the shaft 9 and its connected parts as a “ con 65 tact-point holder 18, which boss is ?rmly se cured to shaft 9. This spring holds the arm forwardly by the action of the pawls herein before described, the pin 32 at the top end of 638,249 ‘ 5 shaft 9 serving as a stop by contacting the sation between two persons is made secret is insulated pin 33, which is attached to the ex shown in Figs. 1 and 2 and is constructed as change-frame 8. follows: Spring 34, at the lower end of the exchange, At 41 and 42 are single-spool electromag serves to carry part of the weight of shaft 9, nets whose coils are not directly connected; and thus relieve the strain of pawl 10 in lift but the two spools are secured to the same ing the shaft step by step vertically. Secured to ratchet 11 isa strip of metal 35, and insulatingly attached to the side of the top of frame 8 at 36’ is a spring 36,whose top end is adapted to contact strip 35 at any point of the upward longitudinal step-by-step move ment of ratchet 11. There is a detent 37, which serves to hold ratchet 15 in any de sired operative position, and detent 37 is se cross-piece, and at 42’ is an arm which is not only an armature for magnets 41 and 42, but 75 the free end thereof projects forward to a dis tance suf?cient to contact the two projections 43 and 44 near the end of a spring 45, whose opposite end is insulatingly attached to frame 8 at 45’. Projection 44 on spring 45 is a piece of insulating material; but projection 43 is integral with the spring, so that current may cured to one end of a pivotal shaft 38, and pass from arm 42’ into spring 45 when in the at the other end is secured a detent 39, which normal position, with arm 42’ in contact with engages with the ratchet-cylinder 11, so that . projection 43, Fig. 2; but no current can pass in the act of release both detents are simul between these two parts when the arm 42’ is 85 20 taneously lifted from the ratchets. drawn in by virtue of electromagnets 41 and At the top of the detent 39 is a laterally 42 to the position shown in Fig. 3“, where the projecting pin 40,0f insulating material,whioh end of arm 42’ is in contact with the piece of has a position, as shown in Figs. 13, 13", 133, insulation 44. 9O so that when the detents 37 and 39 are out of In Fig. 2 is shown a bent arm 46, project 25 contact with the ratchets by the rotation of ing from the base which forms the pivotal end the shaft 38 the pin 40 forces spring 36 out of of arm 14. The vertically-disposed free end contact with strip 35 on ratchet 11, and no cur of arm 46 is in contact with bent wire 48, which rent can pass from the spring into ratchet 11, is in the form of a bell-crank, as seen in Fig. shaft 9, and the frame 8 of the exchange. If, 8C, and is pivoted to a block 49, Fig. 1, then 95 however, ratchet-wheel 15 is actuated one step extending across the front plate of frame 8, forwardly, the spring 36 is dropped into con and at the free end is covered with a piece of I tact with strip 35 by the falling of detent 39 insulating material 49’. into engagement with ratchet 11, as shown in Spring 45 extends from insulator 45’ and 100 Fig. 13A. The shaft 38 is rotated so as to throw 35 the detents out of engagement with the ratch ets by means of an arm 37’, which extends across the frame above a wire tailpiece 10", passes over and rests upon the insulated por tion 49’ of bent wire 48. At 51 is an insulated screw secured to frame 8, and to this screw is attached a spring 52, and at 53 is an arm pro projecting from the pawl 10. The tailpiece jecting from the armature of magnet 13, the 105 is bent so as to form an incline which engages with the inner end of the pin 14",which pro~ jects through the lever 14 and which is car ried into the path of the tailpiece when the lever is drawn forward by the action of the magnet 13. If while the lever 14 is drawn 45 forward the magnet 12 should be energized, so as to draw the arm 10’ forward, and with it other end of which arm is normally near, but not in contact with, spring 52; but should magnet 13 become energized arm 53 Will con tact spring 52 and bend it down, as is shown in Fig. 3, and at the same time the bent arm 46 causes the insulated end 49’ of bell-crank lever 48 to move spring 45 into contact with a cross-spring 55, which has one end attached the pawl 10, the tailpiece 10” would be forced to the frame of the exchange by a piece of in into engagement with the pin 14”, andthe in sulated material, Fig. 3, so that if magnet 41 I15 clined portion would raise the end which is is energized the arm 42’ is free to take the po sition shown in Fig. 3, when if magnet 41 con 38, thus throwing the detents out of engage tinues to be energized until after the current ment with the ratchets upon the shaft 9. Now is out out from magnets 13 and 42 the spring if the magnets 9 should be energized without 45 will drop, with the free end of arm 42’ in I20 deénergizing the magnet 12 the lever 14 will contact with» the piece of insulation 44, in 55 be forced back into its normal position and which position no current can pass between ~ the outer end of the pin 14" will pass under spring 45 and arm 42’, which arm is pivoted 50 under the arm 37’, and thereby rotate the shaft the outer end of the arm 37’, which is bent to and is in electrical connection with the at an angle and is raised above the pin when frame and shaft9. Therefore any one mak 125 the tailpiece is operated. While these parts ing an attempt to cut into either of the lines of 60 are in this position, if the magnet 12 should two already-connected telephones will auto be deénergized the arm 10’ and the pawl 10 matically cut himself out every time his main will resume their normal position; but the switch-arm contacts either of the two contact bent portion of the arm 37’ will engage with points of the two connected exchanges, the the pin 14" and be retained in that position, course of the current to accomplish this being thereby holding the pawls 37 and 39 out of described hereinafter. engagement with their respective ratchets. The manner of attaching the interconnect The cut-out or means by which the conver ing wires 27 to the contact-point strips is 4 638,249 plainly shown in Figs. 4, 4“, 4B, 5, and 5A, the points and then by the successive thrusts of contact-point strips 25 being provided with pawl 14’ on the top of arm 14 be rotated to hooks at their rear ends, which engage with carry the free ends of the wipers into touch loops successively formed at intervals along with any particular point 25 of the row. The auxiliary switch embodied in the parts each of the interconnecting wires, the insu lating-covering of these wires being cut at the 18 20 and contact-points 21, with the wires point of contact, so that the bare wire may be connecting the points with the several wipers soldered to the hooks to insure a perfect con 22 22’ 22", &c., serves as a selector for con 75 nection, the insulating material being slid necting with some particular group of one back on the wire from the hook until after hundred-such as 24, 24’, or 24", Figs. 1 and 2. In operation to follow the course of the the soldering operation, when the insulation is again slid forward close up to the hooks, successive electric currents in making con as shown. 1 In the construction of the shaft 9 and the several parts attached thereto we do not claim any particular method of insulating the wip ers 22, &c. The boss 17 is ?rmly secured to shaft 9 and serves as a stop by contacting frame 8, and 20 thus limiting the downward movement of the shaft. As has been described, the ratchet-wheel 15 is loosely mounted on shaft 9 to revolve and to slide a short distance longitudinally there 25 on; but when in the normal position it is held with the auxiliary switch-arm 20 above the nection between two telephone-substations through the exchange-machines at the cen tral station we will suppose that one tele phone set at a substation is represented by Fig. 14A and the exchange-machine directly connected thereto by two line-wires is Fig. 85 14 and that the number of this telephone is “ 367.” We will also suppose that the distant substation to be called is No. 295 and is rep resented by the telephone set in Fig. 15A and its exchange-machine is Fig. 15, and that not only these two telephone sets, but also the exchanges thereof, are at the normal posi tion, as shown, and that the successive cur plane of the ends of the contact-points 21, and rents of electricity are controlled at the cen the lower end of the downwardly-projecting tral station in each exchange-machine by 95 arm 15" and the lower end of boss 17 both means of three ordinary signal-keys at each 30 rest upon the frame 8, as is shown in Figs. 1, substation, these keys beingtoperated on the 2, and 9. If, however, the ratchet-wheel 15 decimal system, and therefore are denomi is turned one step forward, it will turn upon nated “ units,” “ tens,” and “hundreds” keys shaft 9 against the tension of spring 15’ from and are here designated by the letters H, I00 the normal position shown in the broken lines T, and U. To call No. 295, the H or hundreds 35 at F, Fig. 9D, andin the solid lines, Fig. 90, to key is pressed twice in succession, causing a position when the hole 20’is directly over the two distinct electrical impulses to pass from ?rst contact-point 21A, and should the ratchet~ the main batteryD at the central station over wheel be turned two steps the switch-arm 20 battery-wire 56 to wire 57, Fig. 14, to the sin 105 will have a position with the hole 20’ directly gle-spool magnet 42, then by wire 58 to mag over the second contact—point, as shown, net 13, then by wire 59 to wire 61, to key H, when if from a thrust from pawl 10 against and to ground. (It will be noted that the ratchet 11 shaft 9 is lifted another step the ?rst time the hundreds-key is pressed the second contact-point will be forced into the magnet 13 is energized and the arm 14 is‘ hole at the end of ' the switch-arm 20, and thus 45 not only serves to establish a circuit for an drawn forward, so as to carry the pin 14” from under the end of the arm 37’, which permits the spring 38’ to rock the shaft 38, and the contact-pin and thence by wire 23, Fig. 2, to detents 37 and 39 are both permitted to drop‘ wiper 22’ and thence to some one of the sec upon their respective ratchets 15 and 11, 115 ond group of contact-points in group 24’,Figs. which permits spring 36 to contact metal _ 50 1 and 2, when the wiper is in contact there strip 35 at the side of ratchet-wheel 11, so that 'with, but also serves as a coupler to cause current may pass between spring 36 and shaft 9 to revolve step by step in unison with shaft 9.) Next press the T or tens key nine the revolution of ratchet-wheel 15 through times in succession, causing nine electrical I20 the thrusts of pawl 14’. It must be under impulses to pass from battery D through bat stood, therefore, that the auxiliary switch tery-wire 56 to magnet 12, thence by wire 62 arm 20 must be set in this instance ?rst to to spring 36, contact-strip 35 and shaft 9 to electric current from shaft 9 to the second pin 32, thence to insulated pin 33, then by connect with some one of the groups of con tact-points 24 24’, &c., before the shaft 9, to wire 63 to wire 64, then wire 65 to the key T 125 gether with the wipers 22 22’, &c., are per— or tens-key to ground. (It will be noted . 60 mitted to revolve or the shaft to move longi that when the tens-key is pressed the ?rst time the shaft 9 is lifted longitudinally one step, which causes the auxiliary switch-arm and carries each of the wipers 22, 22’, and 22” to contact one of the pins 21 of the auxiliary upward successively even with the ten hori— switch, and thus make both an electrical and‘ zontal rows of contact-points 25, and it is ob mechanical connection, whereby the thrusts vious that the several wipers may be lifted to of the pawl 14’ will turn shaft 9 with ratchet register with any particular row of contact wheel 15; but in this instance the shaft is tudinally more than a single step. Each suc cessive thrust of pawl 10 lifts shaft 9 one step . i 44. __ _ w A 638,249 lifted nine steps, when each of the wipers 22, magnet 13’, wire 59’ to ringer-magnet 77’, Fig. 22’, and 22" is even with the ninth row, count 15“, then by wire 76’, generator 75’, wire 74’, ing from the bottom row, of contact-points 25 telephone-lever 70’, wire 64’, wire 63’, then 70 in each group.) Next press the U or units key connecting-wire 69 to the interconnecting ?ve times in succession, causing ?ve electrical wire 27 A to wiper 22’ of exchangemachine, impulses to pass from battery D through wire Fig. 14, as shown in proper position in Fig. 16, 56, then wire 57 to one-spool magnet 42, then then through wire 23’, contact-point No. 2 of by wire 58 to magnet 13 and wire 59 to wire the auxiliary switch, and then the switch-arm 75 60 and 61 to the U or units key to ground. 20 thereof, shaft 9, base 8, and arm 42’, spring IO (It will ?nally be noted that the ?rst time this 45, wires 63 and 64, telephone-lever 70 of tele units-key is pressed shaft 9 is rotated one phone setNo. 367, Fig. 14“, wire 74, and to gen step forwardly, which separates strip 35 from erator 75, which completes the ringing-circuit. spring 36, Fig. 131‘, and also separates pin 32 The telephones Nos. 367 and 295 are now re from insulated pin 33, Fig. 16, and it will be moved from their levers 70 and 70’, when the impossible to pass a current through the mag talking-circuit is established, the mechanism net 12, and thereby any injury to the con of the exchange-machine in Fig. 16 being tact~points or wipers by the longitudinal move shown in the operated position connecting ments of the shaft after it has been rotated the two telephones. This talking-circuit is 85 one or more steps will be prevented.) Every the same as the ringing-circuit, with the ex time the U or units key is pressed arm 53 of ception of the ringers and the generators the armature of magnet 13 contacts insulated therefor, which are cut out and the telephone spring 52, which causes an electric current to switched in. While these two telephones are pass from the small battery E, Fig. 14, which off their respective levers, should any one 90 controls the releasing mechanism hereinbe-v attempt to make a connection with either of 25 fore referred to, through wire 67 to one-spool the already-connected telephone—say a per 20 magnet 41, thence by wire 68 to spring 52, son at telephone 118, Fig. 17*‘, should attempt thence through arm 53 and base 8, to which it is pivoted, to shaft 9 and to arm 20 of the auxiliary switch, which arm is" in contact with the second contact-pin thereof, as shown in Fig. 9D, thence by wire 23’ to wiper 22' to contact-point No. 295 of group 24’, Figs. 1 and 2, thence by an interconnecting wire 27A to connecting-wire 69 of exchange-machine, 35 Fig. 15 or Fig. 18, as the case may be, then by wire 63’ (of this exchange No. 295) to and through wire 64’ to telephone-lever 70’, then to call a person at telephone 295, Fig. 18A, and presses the H or hundreds key twice and the T or tens key nine times and the U or units key ?ve times~every time he presses the units-key he closes the contact between arm 53 and spring 52, the electric pulsations from small battery E” in passing over the cir cuit, which includes the low-resistance tele phone 295, being of sufficient strength to hold the arm 42’ against magnet 41 and permit the insulated contact, 44 of spring 45 to fall wire 74’ to the generator 75’, then wire 7 6’ to back of and contact the free end of arm 42’, the ringer-magnets 77 ’, then wire 59’ to mag whereby the circuit is broken, in which event net 13’, then wire 58’ to magnet 42”, thence it is obvious that the bells of neither one of through wire 57’ to battery-wire 56 and wire the connected parties can be sounded nor 73 to small battery E, Fig. 14, which com their conversations be heard. pletes this circuit and energizes the magnet 41. In each of the diagrammatic views is a sep I10 This electric current last described in pass arate small battery E, E’, or E” for each ex 45 ing over this circuit ‘must pass either through the ringing-magnets of the hell or the tele phone or in passing over the lines of two sub stations connected together the current is di vided and passes over both circuits. Usually change-machine in order to show as small a number of exchange interconnecting-wires as possible; but it must be understood in prac tice that one small battery, such as E, of less 115 power than battery D serves for several or the bell-magnets are of high resistance—say the whole number of exchange-machines at one thousand ohms-and the telephone is of the central station. low resistance—~say one hundred ohms. This To cause the several operative parts to re current from small battery E in passing over turn to the normal position after a conversa— I20 this circuit, as described, if it passes through 55 the high-resistance bell-ringer magnets is not of sufficient strength to hold the armature or arm 42’ against magnet 41 after magnets 13 and 42 are deénergized, thus permitting the arm 42’ to fall back into normal position and complete the talking-circuit with any substa tion, magnet 13 is ?rst electrically energized and the current is not cut out until after magnet 12 is energized, which, through the pin 14" and tailpiece 10", causes the detents andl pawls to successively lift from their re I25 spective ratchets, when shaft 9 is ?rst re volved backwardly and then slides down tion with which connection has been made. wardly to the position shown in Figs. 1 and The two telephones Nos. 367 and 295 are now 2. In the downward movement of the shaft in connection, and the ringing-circuit is from the auxiliary switch is caused to resume the 130 generator 75, Fig. 14“, through wire 76, ringer released or normal position by the lower end 65 magnets 77, wire 59, and magnet 13, then wire of the downwardly-projecting arm 15” con 58, magnet 42, and through wires 57, 56, and tacting the frame 8 before the shaft 9 has 57’, Fig. 15, to magnet 42", then wire 58’ to reached its lowest position, which causes the ' 6 638,249 boss 17 and the contact~point holder 18, which and longitudinal movement of the shaft, an are secured to the shaft, and by the down ward motion thereof to withdraw any contact auxiliary switch mounted on the shaft and consisting of a series of insulated contact point 21 which may be engaged with hole 20' in the auxiliary switch -arm 20, when the resiliency of spring 15’ causes a backward movement of the ratcl'iet-wheel 15 to the some one of the switch-arms, a ratchet-wheel points each having electrical connection with 7O loosely mounted upon the shaft to revolve or slide longitudinally thereon and having an normal position, with projection 15” resting arm attached thereto which forms a terminal against projection 19 of the contact - point holder 18, Fig.‘ 90. in electrical connection with a substation, 75 the first rotary step-by-step movements of It will be noted that since the boss 17 and the ratchet-wheel adapted to cause the arm at the contact- point holder 18 are secured to tached thereto to register with some one of the shaft 9 these two parts are ?rst carried around to the normal position shown in Figs. 1 and 2 with the ?rst backward revolution of the shaft and that the ratchet-wheel 15 is re volved on the shaft, together with the auxil said insulated contact-points without turning the shaft, butthe ?rst longitudinal movement of the shaft couples the arm with the contact point with which it is in register, whereby any subsequent stepby-step rotary move iaryswitch-arm 20, always after the shaft has ments of the ratchet-wheel cause the shaft reached its lowest position. The shaft 9 be to revolve in unison therewith for the purpose 85 20 ing mounted to operate longitudinally in a stated. vertical direction, it is obvious that most of 4. In an electrical exchange, the combina the weight thereof may be counter balanced tion, with contact-points, of a longitudinally by the upward pull of spring 34, and since a movable shaft, a selector thereon, a lock for step-bearingis provided at the lower end upon the shaft, said selector and lock being in such 25 the pointed upper end of rod 30, which is dis relation to each other and to the shaft, that posed within spring 31, friction in the bearing when the shaft is moved the ?rst step longi thereof is reduced to avery small amount,even tudinallyit will engage with the selector and when the shaft is made much longer than is will become disengaged from the lock, sub shown in the drawings, to receive an addi stantially as set forth. 95 5. In an electrical exchange, the combina tional number of switch-arms, when an ad— tional number of groups of contact-points are tion, with contact-points, of a longitudinally necessary in large exchanges. movable shaft provided with a series of pins ‘Ve claim as our invention—— arranged parallel therewith, a platform, a 1. In an electrical exchange, the combina lock, and a selector provided with two arms, 35 tion, with a series of contact-points arranged one of which normally‘rests upon the plat in groups, of a switch provided with an arm for form and the other one is adapted to be placed each group, a series of contact-points mounted in engagement with the pins, said parts be independently of the switch but in electrical ing in such relation to each other that when communication with the different arms, and the shaft is moved the ?rst step longitudi 105 a selector or auxiliary switch-arm rotatably nally it will simultaneously cause the pins to and longitudinally movably mounted upon engage with one of the arms of the selector the ?rst~mentioned switch, and means for and to become disengaged from the lock, and establishing electrical communication with when it is moved the last step in the opposite either of said groups through said selector, direction it will be simultaneously disengaged I10 from the lock and the pins will be disengaged 45 substantially as set forth. 2. In an electrical exchange, the combina tion, with a series of contact-points arranged in groups, of a shaft provided with an arm for each group, a series of contact-points in electrical communication with said arms, a selector or auxiliary switch rotatably and 1on gitudinally mounted upon said shaft, the con tact end of which is normally out of engage ment with said second~mentioned contact 55 points, and means for rotating the selector, and means for moving theshaft longitudi from the arm of the selector, substantially as set forth. 6. In an electrical exchange havinga switch or connector, of an auxiliary switch or se I15 lector, motor-magnets for operating the same, a circuit for each magnet, two single-spool electromagnets, one of which is in the circuit of one of the motor-magnets, a separate cir cuit for the other spool, a cross-piece and an I20 armature common to both of said single-spool magnets, the armature being adapted to lock nally, whereby contact is made between the se— the switch, substantially as set forth. lector and one of the points, only after the 7. In an electrical exchange, the combina selector has been moved one or more steps tion, with a series of lines from distant sta 125 from its normal position, substantially as set tions, of a series of connectors at the ex forth. change, one for each line, motor-magnets for 3. In an electrical exchange havinga shaft each connector, a cut-out for each line be with a plurality of switch~arms insulatingly tween the connector and the distant station, attached thereto and each adapted to contact an electrical circuit for the cut-out including 65 any one of some group of contact-points by the connector and the cut-out, and means for virtue of either a rotary or a combined rotary automatically passing a current of electricity 638,249 ‘7 through the cut-out circuit to disconnect its 10. In an electrical exchange, the combi 25 connector from either of two connected lines, nation, with supports, of a shaft journaled substantially as set forth. 8. In an electrical exchange, the combina tion, with a support, of a shaft journaled ver therein provided with contact-arms, contact points, an arm pivotally secured at the lower end of the support, a rod in the arm, the up— tically therein and provided with contact per end of which acts as a step for the shaft, arms, of aspring-actuated vertically-movable a spring secured to the arm and to the lower step at the bottom of the shaft, means for end of the shaft and surrounding the rod and moving the shaft upwardly step by step and shaft, and means for moving the shaft up IO means for releasing the same and permitting ward step by step, and means for releasing the shaft to automatically resume its normal the same and permitting it to automatically 35 position, substantially as set forth. resume its normal position, substantially as 9. In an electrical exchange, the combina set forth. ' tion, with a support, of a shaft journaled In testimony that we claim the foregoing therein and provided with contact-arms, of we have hereunto set our hands, this 19th day contact-points, an arm pivotally secured at of August, 1895, in the presence of witnesses. the lower portion of the support, a rod in the arm, the upper end of which acts as a step ALEXANDER E. KEITH. for‘ the shaft, a spring connected with the JOHN ERIGKSON. 20 arm for partially counteracting the weight of CHARLES J. ERIOKSON. the shaft, and means for moving the shaft up wardly step by step, and means for releasing the same and permitting the shaft to resume its normal position, substantially as set forth. Witnesses: JOSEPH HARRIS, OSCAR SNELL.