US777807A - Telephone system and apparatus. - Google Patents

Description

' 170.777,807. PATBNTBD DEC. 2o, 1904.

E. E. MBS.

TELEPHONE SYSTEM AND APPARATUS.

APPLIOATION FILED JUNE 23,1899.

No MODEL. 3 SHEETS-SHEET 1.

r I I l C) O 33.772916 30 Ely? 30 1771951 50 36 @g GD 54 34 QD GD PATENTBD DEG. 20, 1904.

ELE. RIES.

TELEPHONE SYSTEM AND APPARATUS.

APPLICATION FILED JUNE 23.1899.

3 SHEETS-SHEBT 2.

N0 MODEL.

y /N VEA/Tof? 2,0 @y

A fr0/.W5 rs WV'TNESSES PATENTED DEC. 20, 1904.

E. E. KIES.

TELEPHONE SYSTEM AND APPARATUS.

APPLICATION FILED JUNE 23.1899.

3 SHEETS-SHEET 3.

NO MODEL.

W/TNESSES /NVENTO/ f4 /gwjfh ATTORNEYS UNITED STATES Patented December 20, 1904.

PATENT OEEICE.

TELEPHONE SYSTEM AND APPARATUS.

SPECIFICATION forming part of Letters Patent N o. 777,807, dated December 20, 1904. Application led June 23,1899. Serial No. 721,521.

To all whom, it may concern:

Be it known that I, ELIAS E. RiEs, acitizen of the United States, and a resident of New York, in the county ot' New York and State ot' New York, have invented certain new and useful Improvements in Telephone Systems and Apparatus, of which the following is a specification.

My invention relates to a telephone system wherein the apparatus is so organized and connected that by the mere act of picking up the receiving' instrument and placing it to the ear the circuits or connections at the subscribers station will be automatically changed through the operation of a self-acting gravity or automatic switch contained in or carried by the instrument in a manner to signal or call the central oiice and put the apparatus in condition for conversation, while on restoring the instrument to its normal position the circuits will be automatically restored to condition for receiving a signal, and at the same time a ringing-oii2 or clearing-out signal will be transmitted to the central oiiice.

One of the objects of myinvention is to permit the generator or generators which supply energy for the various operations of signaling, ringing ofi, and conversation to be all located at a single or central point, preferably at the central station, and at the same time to permit the invention to be applied to existing exchange apparatus without derangement of the systems at present in use.

In carrying out my invention I prefer to make use of areceivinginstrument ot' the form described by me in another application for patent iiled as a division of the present application and so constructed as to make the use of gravity-hook switches or. similar devices unnecessary, yet to insure the proper changes of circuit in the apparatus when the receiver is laid aside upon a desk or table or other ilat surface after being used. This device embodies as a part of the instrument a gravity-switch, and the instrument is so constructed that no matter what position may be given the instrument when it is laid down upon a flat surface it will automatically right itself by the action of a self-contained weight and assume a position such that the contained switch will under the iniiuence of gravity change the circuit connections back to the normal condition.

I prefer to employ a gravity-switch of the type in which mercury or other mobile conducting medium acts as the circuit-changer, but might use other means operated by gravity without departing from the invention.

My invention relates also to the special manner oi' carrying out the invention in connection with systems wherein self-restoring linedrops are employed and to systems wherein luminous signals are employed, as will be more particularly described and then specified in the claims.

In the accompanying drawings, Figure l is a sectional elevation on the line A A, Fig. 5, of a telephone-receiver having the automatic circuit changing and switching appliances adapted for use in carrying out the invention. The figure also shows the instrument as organized to be self-righting, so that the portions of the gravity-switch contained in or mounted on the same may be caused to assume proper condition for completing the normal connections, or those which exist when the instrument is out ot' use. Fig. 2 shows the same instrument in sectional elevation on the line B B, Fig. 8, but with the auxiliary signaling-key omitted and with a mouthpiece of the ordinary construct-ion. Fig. 3 shows the instrument in partial section upon its side and about to right itself. Fig. 4 is a top View of the mercury-cup or contact-shell of the switch, showing the position of the holes in its flange. Figs. 5, 6, 7, and 8 show in plan the supporting-disk or switchboard within the cap of the instrument with various arrangements of terminal posts and connections adapted for use with different arrangements of telephone circuits or connections. Fig. 9 is a diagram illustrating a telephoneexchange having clearing-out drops and subscribers circuits furnished with Yapparatus such as illustrated on Sheet 1 oi' the drawings. Fig. 10 shows a bank of line-drop coils as connected to a bus-wire. Fig. ll illustrates diagrammatically my invention as carried out in connection with a luminous signal system.

Referring to Figs. l, 2, 3, and 4, 9 is a con- IOO ical shell of conducting material, like iron, having a flange adapted to rest upon the shoulder of the block or body 8 of the instrument, and 16 is a disk or piece of insulating material, like hard rubber, setting down upon the top of said flange and fastened down upon it by screws 14, which pass through the disk and through holes in the fiange into the block or body 8. Nesting within the conical conducting shell or cup 9 is a conical block 60 of insulating material, which is fastened to the under side of the disk 16 by means of abolt 62, the head of which forms a contact-terminal tip of the block 60 and constitutes one of the contacts of the gravity-switch. Contact-terminal 61 is tapped to receive the thread of the screwbolt 62, which extends vertically through the disk 16 and block 60, and serves the double purpose of fastening the terminal, the block, and the disk together and establishing an electrical connection between the tip and the parts Within ascrew-cap 15, which screws upon the edges of the disk 16. The contact-rings 11 12, of any conducting material, may be either embedded in the material of the block 60 or, as shown, may be clamped between a shoulder on the block and thelower surface of the disk 16, being at the same time insulated from one another by an interposed washer or ring. rlhe bolt 62 serves as a clamping-bolt for this purpose. The space between the conical block and the cup 9 forms a mercury-chamber, withi in which a mass of mercury 7 shifts its position under the action of gravity according to the position of the instrument. In the normal position shown in Fig. 1 the mercury completes the connection between the shell and the bolt 62, When the instrument is turned to horizontal position for the purpose of listening, the mercury takes the position indicated in Fig. 3, and thereby completes a connection from the shell to one or both of the rings 11 12 and also in some uses of the instrument completes the connection from one of said rings to the other.

1n some applications of the apparatus according to my invention an auxiliary switch or signaling key may be used upon the top of the block 16, the parts of said switch being caused to shift position by pressure applied upon a knob 20, the shank of which extends through the cup 15 and bears upon the shiftable spring-contact of an auxiliary switch. rlhe hollow stem open at its bottom forms a passage for a conductor-cord 45, containing the conductors which are attached to the various terminals within the cap 15 upon the top of the disk 16. The button 2O receives the pressure of the fingers, which are permitted to rest naturally upon it while assisting the other fingers and thumb in holding the instrument, and this pressure is communicated through the shank to the parts of the auxiliary switch.

17 is the contact-spring of the auxiliary switch and normally rests against the under side of a spring 18, which may be termed the back contact; but the application of pressure through the button 2O breaks the connection with the spring 18 and establishes connection with the upper side of the contact 19, both contacts 18 and 19 being upon the upper surface of the disk, as indicated in Fig. 5. The

-hollow shank or stem to which the knob 2O is fastened by a screw connection, as shown, en-

gages an oblong opening in the spring 17, so

as to hold the shank from turning and twisting the cord 45 when the button 2O is unscrewed from its shank preparatory to unscrewing the cap 15 in order to attain access to the terminals upon the top of the disk 16. The contact-spring is fastened upon the disk by a screw 71, though for some uses of the instrument it may be fastened beneath the head of conducting-bolt 62, as indicated in Fig. 6. 1n the former case a conducting-strip 69 or other device is used to form connection between the head of bolt 62 and the bindingpost 70, seated upon the outer end of said strip, and connection from the latter to the bolt 71 is made through either an external bell-circuit whose terminals are secured to said posts and 71 or directly by a wire, (indicated by the dotted line, Fig. 5,) according to the manner in which the signal-bell is to be included in the circuits. Spring 18, serving as the upper or normal contact for the free end of spring 17, is fastened beneath a shoulder of connecting-post 35 upon the disk or board 16. The lower or signal Contact 19 is similarly connected with a post 36.

24 is a line-post of the instrument, which post is in direct connection with the fiange of the cup 9. For this purpose it is made to pass through the disk 16 and to have its ends set against the flange, so as to be in conducting connection with it.

The conducting pin or bolt 32 passes through the disk or board 16 and is tapped directly into the lower ring 12. Said pin 32 is insulated from upper ring 11 at the point where it passes through the latter by an insulatingbushing, as shown in Fig. 2, and its head is connected with the terminal post 34 on the top of the disk 16 by a 'strip of conducting material on the upper surface of the disk 16, as shown in Figs. 5, 6, 7, 8, secured at one end beneath the head of screw pin or bolt 32 and at the other end beneath a shoulder of post 34, or the connection may be made in other ways. The upper ring 11 connects upon the surface of the disk in a similar way, by means of a screw pin or bolt 27, with the conducting bolt or pin 28, which passes down through disk 16 and the body or case 8 of the instrument and is connected to one terminal of the telephone-receiver coil 5, the other terminal of which coil is joined to a conducting pin or bolt 29, similar to 28 and bearing at its upper end the terminal connecting-post 30.

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. 2, the conducting bolts or In the form of receiver shown in Figs. l, 2, and 3 the permanent magnet 73 is of ring form, with two consequent poles, and the softiron cores for the two coils 5 are of elbow form, as shown, and have their horizontal arms fastened to the magnet at the two consequent points, respectively, while their vertical arms carry the coil. As shown in Fig. pins 29 28 serve the additional purpose of clamping the magnet in position. The bolts are insulated from the magnet by proper bushings. as shown.

The instrument is made self-righting by heavily weighting its lower end and by giving a properl curve or shape to the sides of the instrument at and near its base, as indicated at 74. rlhe weight-ing is preferably given by lling in the earpiece with a mass 75 of heavy metal, like iron or lead, as shown in Fig. 1, the effect of which when the instrunient is laid down upon its side or in other position than the vertical is to cause it to assume the vertical by rocking upon its curved side 7 4L under the action of the weight. By thisdevice the user need pay no attention to the manner in which he lays the instrument down, for it will automatically restore itself to such position that the gravity will change the circuits to the normal or desired condition. The instrument may therefore be placed in the hands of careless users and at the same time' hooks or special supports for the instrument be dispensed with. Obviously the instrument may be weighted by other means or in other ways to accomplish the same result.

Fig. 2 shows an earpiece of the ordinary form which is interchangeable with that shown in Fig. 1 and may be used where the instrument is used as a part of a wall set, in which case it normally hangs suspended from its cord.

The arrangement of terminal connections shown in Fig. 5 permits the local or subscribers bell to be included in circuit between posts and 71, so that when the key is 0perated to make connection between spring 17 and contact 19 the bell being still in circuit will ring simultaneously with the transmission of a call by the subscriber. When this feature is not desired, the posts 70 and 71 may be short-circuited, as indicated in Fig. 5, and the bell may be placed in the connection running from terminal 35, so as to be disconnected and remain quiet when the key is operated, but still be in circuit so as to respond to an incoming call. The equivalent of shortcircuiting 70 and 71 is accomplished by the arrangement shown in Fig. 6, wherein spring 17 is secured directly to bolt 62. If a bridging-bell is used, as indicated at right of diagram Fig. 9, (that is, a bell connected across the wires leading to the line-post 24 and the return-wire leading to post 30,) terminal posts 35 and spring 18 may be dispensed with, and the disk may then have the sim pliiied arrangement shown in Fig. 7. The disk shown in Fig. 8 has the auxiliary push-button or key omitted and is adapted for use where the bell is to be connected in the wire leading directly from tip-bolt 62, as indicated at the left of diagram Fig. 11.v In this case the bolt carries or is directly connected with a terminal post, like 35, Fig. 2, for attachment of one of the wires of cord 45.

The diagram Fig. 9 shows the invention as applied to an exchange employing annunciator and clearing-out drops and without interfering with the use of the existing central source of energy for transmitting signaling-current from central to the called subscriber over his line. The diagram also shows the improvement, which consists in dispensing with the use of sources of signaling-current at the various subscribers stations for permitting them to call the central ofiice and in centralizing the energy used for this purpose at the central oflice or other desired point common to a number of subscribers. In thi's improvement the subscriber, just as in the present systems, operates the line and clearing-out signals at the central oflce over a wire used in conversation; but the electric source controlled by him at his station for this purpose instead of being located at said station is at the central oiiice. It will also be observed from the subjoined description that the system shown embodies the usual metallic line-circuit for conversational purposes and that the signaling from the subscriber to the central, and Vice versa, is done by grounding said metallic circuit at the subscribers station, the generator being in the ground at the latter point and serving to supply any number of circuits.

In the diagram two subscribers stations only are shown, the one at the left being provided with the automatic telephone, having terminal posts and connections such as are furnished by a disk, like that of Fig. 5. The bell48 being connected between posts 70 and 71 rings both on outgoing and incoming calls. The one at .the right has an instrument furnished with aterminal disk, like Fig. 6, and the bridging-bell .-18 being connected across the two main-line posts 77 78 rings on call from central, but is silent on outgoing calls. 76, at both stations, is aniain ground-post, to which connection is made from post 36, thus providing a connection which when ccmpleted furnishes a circuit for the ringing source of energy by which the subscriber calls central or operates the clearing-out signal. The station at the right requires no upper or back contact-spring 18, owing to the fact that the bridging-bell is used. In the system illustrated a second line-wire 79 for each station provides a metallic return, as usual in the art. The secondary 31 of the transmitter induction-coil is connected to the main post 77 of the line 79. The local-battery primary 50 and transmitter 51 are connected to main line 59 Ioo by main post 78. Briei'iy, the apparatus at the central station comprises the following parts of the usual construction, but in addition thereto a source ot' energy in proper connection to enable it to come into action and operate the line and clearing-out drops or other signals when the subscribers instrument completes the proper circuit. One pair only ot connecting-plugs and their accessory appliances are shown, with a corresponding pair of spring-jacks to which the subscribers lines are connected. The tips 8O of the plugs are connected through one of the conductors 82 of the usual flexible cord-circuit, and the sleeves 81 of said plugs are connected by the other conductor, 83, of the cord-circuit. The tips 8O when the plugs are inserted register with springs 8110i the spring-jacks,with which are connected the main lines 59, and sleeves 81 register with ring 85, to which the linereturns 79 are connected, thereby connecting the subscribers circuits for conversation. 86 indicates the usualringing or calling' key by which a subscriber is called, and 187 the usual calling-generator,fr0m whose terminals circuits run to contacts of the ringing-keys, adapted to be engaged by springs 87, joined to the contacts 8O 81 of the plug. When either key is operated after insertion of the plug into the spring-jack, it disconnects the springs 8O 81 from the contacts through which they are joined to the cord-circuit and connects them to contacts leading to the generator 187, thereby causing current to flow from the latter over the circuit 59 79 and subscribers bell 4:8. A listening-key 88 for the cord-circuit has two contact-points or anvils connected, respectively, with the conductors 82 83, as shown, and two corresponding contact-springs connected, respectively, with the operators listening-telephone 89. Vhen the plunger-key is allowed to rise, it brings the contact-springs and anvils into engagement, thereby connecting the telephone to the cord-circuit. On each plug is a ring or sleeve'90, entirely insulated from all other portions of the plug and adapted to register with two springs, as shown, to connect them together when the plug is inserted in the jack. One of said springs connects directly to earth or a common return, while the other is connected through a restoring-coil 91 of the corresponding line annunciator or drop with a wire which is in connection with the grounded generator 92 common to the circuits. rlhe connection of the springs by the ring 90 allows current from generator 92 to energize the restoring-coil and return the drop, as well understood in the art. Testthimble 98, joined to wires running throughout the switchboard and in connection therethrough with the test-thimbles and jacks of other sections furnish a busy test. Each is connected at its own section with the spring, Which 1s grounded through sleeve 90 when When the operatorv at the plug is inserted.

any other section of the board touches the test-thimble at her section with the tip 8O of her plug, a click in her telephone, which has a ground connection 94 from the middle of the telephone-coil, indicates line free, because generator 92 finds circuit through thimble 98, tip 80, cord-circuit 82, and contacts of listening-key. 1f, however, a plug has been inserted into the spring-jack of the line wanted at any other section of the board, the current is short-circuited from her telephone by the plug-sleeve 90, as stated. Silence being then the result of the test, the operator will know that the line is busy.

95 is the actuating-coil of the usual clearing-out drop or annunciator, and 96 the restoring-coil thereof. rlhe former is a highimpedance coil connected across the two sides of the cord-circuit 82 88 and comes into action when eithei'` of the two connected subscribers rings ott. Coil 96 comes into action when the operator listens in by operating her key 88, thereby bringing insulated spring 97, connected to coil 96, into contact with an anvil connected to earth, and thus completing the circuit of a generator 98, which is connected to coil 9.6 and grounded, as shown. The line annunciator or drop is ot' the self-restoring character. Its line-coils 99 operate to cause a drop to be displayed when the subscriber calls central; but said coils instead of being connected across the line-wires 59 79 and carrying current from a generator are connected between one pole of central generator 100, which may be common to a number of drops, and one or both of the lines 59 79, while the opposite pole of said generator is connected to earth or suitable return. The generator may be a battery, motor-generator, or power driven magneto, as desired and serve for any number of lines, as indicated in Fig. 10, where a number of line-drop coils are shown tapped onto a bus-wire fed by the generator 100. It is preferable to use a motor-generator or battery supplying direct current, since possible inductive disturbances are thereby avoided. rl`he same generator may also supply current to operate the coils 95 of the clearing-out drop, which has heretofore been operated by a generator at the subscribers station. For this purpose it is connected to the side 83 of the cord-circuit or otherwise connected with one terminal of the several coils 95 of the exchange, their opposite terminals being connected with the side 82 of the cord-circuit which connects with the plug terminal that is in connection with the side of the subscribers circuit which is usedJ in ringing o. In this case the coils 99 should, like coils 95, be high-impedance coils to prevent the short circuiting of the voice-currents. Righthand subscriber is shown as having called central, and the latter is ringing up left-hand station by operating the proper ringing-key 86.

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The general operation is as follows: In grasping and lifting' his instrument to the ear the subscriber closes ringing-contact19, thereby operating the line-drop by current from generator over the following circuit: from 100, line-coil 99, line-wire 59, shell or cup 9, mercury 7, contact 61, bolt 62, spring 17, contact 19, post 36 76 to earth, and back to the generator 100. The act of lifting the instrument also causes the mercury or gravity switch to change to position and change thc circuits to condition for conversation. Central operator then shoves one plug of a cordcircuit into a line-jack of subscriber calling, one eiect of which is to restore the linedrop by completing a circuit through restoring-coil 91 as follows: from generator 92, to coil 91, and by springs bearing on plug-collar 90 to earth, and back to generator. The operator then throws listening-telephone 89, by means of key 88, into the circuit 59 79 and obtains number of line wanted. Desiring to call subscriber, the operator uses the other plug of the cord-circuit and after testing by means of tip 80, as explained, inserts plug into line-jack of subscriber wanted and operates ringing-key 86 to throw current from generator 187 into circuit 59 79, thereby ringing the bell of subscriber wanted over following circuit at his station: from line 59, cup or shell 9, mercury 7, contact 61, bolt 62, post 70, bell 48, post 71, spring 17, back contact 18, line 79, and back to central, and subscriber on picking' up his instrument places the circuit of his own instrument in condition for conversation automatically, the line-circuit being now from 59 to shell 9, mercury 7, contact-ring 11, coil 5, post 30, secondary 3l, and to main line 79. The ground connection by tip-contact 61, bolt 62, bell 48, spring 17 and contact 19 is at the same time broken by the flow of mercury away from the said tip; but prior to this change of connection there will be a momentary ground from line 59 by shell 9, tip 61, bell 48, spring 17, and contact 19, which will, as in thecase of the subscriber at the right, cause the line-coil of the drop to act and which would be effective in the same way in calling central if subscriber at the right were the rst to call. In ringing off either subscriber on laying down his instrument causes the switching devices to automatically change the connections and a circuit to be established through the clearingout drop-coil 95 as follows, the pressure on the button being continued for this purpose: from generator 100, to cord-circuit 83, coil 95, cord-circuit 82, tip 80, line 59, shell 9, mercury 7, tip 61, bolt 62, spring 17, contact 19, ground, and back to generator. This actuates the clearing-out drop, and the operator noticing this listens in to ascertain whether 'the subscribers are through talking or whether one of them desires another connection. The act of listening in restores the shutter of the clearing-out drop by the action of coil 96 in the usual manner.

As will be observed, the work is done without interfering with the use of the ordinary central-oflice equipment, and the signaling to and from central and ringing off is accomplished entirely by, physiologically speaking, an automatic action and by the use of centralized sources of energy only. This is due to the fact that the natural pressure of the hand in holding the instrument is applied upon the button which operates upon the spring 17, thus keeping the circuit closed at this point, so that the shifting of the mercury, owing to change in position of the instrument as it is placed to the ear and removed therefrom, will produce the changes in the circuit, as before described.

Diagram Fig. 11 shows the invention as applied and carried out in connection with a telephone system employing luminous signals at central and by the use of centralized energy. The lines 59 79 connect, respectively, with the springs 84 84 of a spring-jack, which are engaged, respectively, by tip 80 and collar or sleeve 81 in the plug, said tip and collar being respectively connected with contactsprings of a ringing-key 86 and by inner anvils of the latter with the two sides 82 83 of the cord-circuit, each of which sides contains two sections 112 of a divided repeating induction-coil. Lines 59 79 are also normally connected through the normally closed back contacts of a switch 104 with relay 101 and a battery or other generator 114. Relay 101 serves to close local circuit 103 to illuminate a line signal-lamp 113 when the lines 59 79 are connected by the automatic gravity-switch within the receiver in tilting the same to lift it to the ear. A relay 102 operates to open the switch 104 to extinguish the lamp. Bridged across the conductors 82 83 at a point between the divisions of the repeating-coil is the supply-battery 105, supplying energy to the lines 59 79 and the transmitters 51 at the subscribers stations. One terminal of battery 105 is grounded for test purposes. Another bridge contains the operators telephone 89, listening-key 88, and transmitter. One or both of the outer anvils of the ringingkey may connect with the calling-generator 100, so that the current therefrom will flow over both wires 59 79 when proper connections exist and through the ground connection containing the bell at the subscribcrs station. The inner an vils connect to the cordcircuits. Said generator is similarly connected to all the ringing-key contacts of the station. The plug of the jack carries, as usual, the insulated sleeve 110, adapted to connect with the thimble 109, which latter is connected to ground through the relay 102, which operates to extinguish line signal-lamp by opening the double-pole switch 104. In each division of the cord-circuit 83 there is a re- IIS ISO

y and return-line 79.

f)5 ble break-switch 104.

lay-magnet 106, whose armature when the magnet is energized closes the circuit of battery 107 through a relay-magnet 108, the armature of the latter serving while attracted to open the branch maintaining the clearing-out lamp 111. The circuit of relay-battery 107 after passing relay 108 is continued through the insulated sleeve 110 of the plug for the spring-jack through the sleeve 109 and restoring relay 102 to earth and back to relay-battery 107. In circuit with one of the clearing out lamps 111 for each pair of plugs is a relay-magnet 115, which controls the local circuit of a supervisory lamp 116, placed in view of the chief operator by closing circuit on its front contact, thus causing both lamps'111 116 to be lighted and extinguished together. In the apparatus at the subscribers station the signal-bell 48 is in the direct connection to earth from post 35, joined to the tip-contact 61 of the automatic gravity-switch. Thetelephone-transmitter 51 of the subscribers is in the direct line-circuit and operates by varying the contact to control the action of the central energy talkingbattery 105, connected to the cord-circuit, by which two subscribers are joined. The upper contact-ring of the mercury switch is connected, as already explained, to the coil 5 of the telephone-receiver, the opposite terminal of the latter being connected to the post 30 The lower contact-ring 1Q need have no connecting-post 34 or may be dispensed with, or the post if it exists may be left unconnected in this use of the instrument. The bells 48, being grounded from the tip-contact 61, will obviously ring only when central transmits a call through pressure on the ringing-key 86. No auxiliary push-button is employedy in the arrangement shown, the contact-rin, ,l 11 serving by reason of the connection and arrangement of devices described as the signaling-contact, since in addition to automatically changing the circuits to condition for receiving and transmitting conversation it operates by closing connection from one line, 59, to the other, 79, to perform the signaling function by completing the circuit of the battery 114 at the central station. The diagram shows two subscribers connected at the central exchange. Right-hand station has called central by lifting the receiver, thereby causing the gravity-switch within it to shift position and by completing circuit to the battery 114 at ring 11 to cause lamp 113 to light. Central has responded by plugging in one end of the cord-circuit into the spring-jack of the right-hand station, thereby extinguishing calling-lamp by completing circuit of battery 107 through contacts of relay 106, (which have been energized by the battery 105 on insertion of the plug,) coils of relay 108, sleeve 110 of the plug, test contact-ring 109, and relay 102, which latter operates to open the dou- In addition the relay 108 by opening the branch containing the clearing-out lamp 111 keeps the latter extinguished until the subscriber by laying' down his telephone causes the mercury switch within the same to shift to the position shown at the left-hand-subscribers station, thereby opening the circuit-battery 105 at ring 11. rThe relighting of the lamp gives notice that the subscribers are through talking. Central having-ascertained from right-hand station by bridging in the head-phone 89 that connection is desired with the left-hand station has inserted the other plug of the cord-circuit into the spring-jack of the latter and has by pressing the ringing-key 86 transmitted calling-current from ringing-battery 100 over springs and outer anvils of the ringing-key to line 59, thence through shell or cup 9, mercury 7, tip 61, and bell 48 to earth. When subscriber to the left picks up his receiver, the switch within the same completes the talking-circuit of the battery 105 through the two halves of the central repeating-coil, the other half of which acts as the secondary. No local inductioncoils or other talking-batteries are used at the subscribers station, the transmitter being in series with the receiver-coil, nor are there any condensers required at the substations, as would be the case if the bells were bridged across the lines 59 79, as has heretofore been the practice.

From what has been said it will be evident that by means of the invention a simple, rational, self-contained, and eiective telephone system of great flexibility is provided that reduces thel number of the manual operations required by and aords many other advantages over thc existing methods of conducting telephonie communications and the more or less complicated apparatus for practicing the same, inasmuch as by means of the automatic telephone only a single movement of the hand, (leaving the other entirely disengagech) and that movement promptly and almost unconsciously performed in a most natural and instinctive manner without any necessar y previous training, is all that is required to commence, carry on', and finish a conversation.

What I claim as my invention is- 1. 1n a telephone-exchange system having a clearing-out drop connected across the cordcircuit, the combination of a grounded generator connected to said circuit at the central oflice and a telephone-receiver at the subscribers station embed ying an automatic gravity-switch adapted when held to the ear to connect the two sides of the line and to complete a ground connection when the instrument is placed in its normal position.

2. In a telephone-exchange system, a centralized source of energy grounded at the exchange and connected to the operators ringing-keys, in combination with metallic subscribers circuits each having a receiver carrying an automatic gravity-switch that closes a IOO ground connection and breaks connection between the two sides of the circuit in one position of the receiver, and unites the two sides of the circuit and breaks the ground connection in the other position.

3. In a telephone-exchange system, the combination with line-drops or other signals at the central station and a source of energy at said station for operating the same, of subscribers instruments each having an automatic gravity-switch embodied in the telephone-receiver and adapted in one position to connect the two sides of the line, and in the other to break said connection and connect one side to an auxiliary switch mounted on the telephonereceiver, said auxiliary switch being adapted to control a connection whereby the line-signal may be operated by the source of energy at the central station.

4. In a telephone-exchange system, the combination with metallic subscribers circuits of a central source of energy, operators ringingkeys adapted to connect the two poles of said source to the two sides of the metallic circuit respectively, grounded source of energy at the central oiice, line-signals operated thereby, a telephone-receiver at the subscribers station, an automatic gravity-switch mounted thereon and adapted to complete the connection between the two sides of the circuit in one position of the receiver, and in the other position to break said connection, and a manual switch mounted on the receiver and adapted to place one side of the circuit in direct connection with the ground.

Signed at New York, in the county of New York and State of New York, this 20th day of June, A. D. 1899.

ELIAS E. RIES.

Witnesses:

WM. H. CAPEL, JULIA E. LUDLow.

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