US405867A - Telephone-exchange apparatus - Google Patents

Description

(No Model.) 3 Sheets-Sheet 1. P. Gr. BEACH.

TELEPHONE EXCHANGE APPARATUS.

Patented June 25, 1889.

' `3 Sheets-Sheet 2,

(No Model.)

F.. G. BEACH. TELEPHONE EXGHANGB APPARATUS. No. 405,867. Patented June 25, 1889.

IIII A 3 Sheets-Sheet 8.

(No Model.)

E. G. BEACH.

TELEPHONE EXCHANGE APPARATUS.

No. 405,867. Patented June 25, 1889.-

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UNITED STATES PAT-ENT OFFICE.

FRANKLIN G. BEACH, OF CHICAGO, ILLINOIS.

TELEPHONE-EXCHANGE APPARATUS.

SPECIFICATION forming part of Letters Patent No. 405,867, dated June 25, 1889.

Application filed December 8, 1887. Serial No. 257,309. (No model.)

T0 all whom iv' may concern:

Be it known that I, FRANKLIN G. BEACH, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone Exchange Apparat-us, (Case 5,) of which the followingl is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone-exchange apparatus, and more especially to that system of telephonie communication known as the multiple-switch-board system. Asis well known, in multiple-switch-board systems separate boards are provided, each board bcing furnished with a separate switch or terminal for each of the telephone-lines of the cX- change. These boards are preferably placed end to end, so as to form one continuous line of switch-boards. These boards, when once placed in line, are sometimes spoken of collectively as the multiple switch-board, while the different duplicate portions thereof are termed sections of the multiple switchboard. I shall, however, in this description speak of the duplicate sections as different switch-boards. The object of duplicating the boards is to facilitate the operation of large exchanges. The cables necessary to carry the wires are arranged at the rear of the board and connected with the different parts of the spring-j ack switches. The spring-jack switches have heretofore been built up in strips which strips have been inserted from the rear of the board. After the wires are connected with the spring-jack switches it has been quite difficult to get at the springjacks to make repairs when required.

In all multiple-switch-board systems of telephone-exchange it is essential that a test be provided to indicate to the operator at any board whether a given line is or is not busy at one of the other boards. This test is usually accomplished in the systems heretofore devised by the making of a contact or cross by the plug when inserted in a springjack, such contact or cross being between the test-circuit. and the main-line circuit. The test-circuit is normally open, and hence when thus crossed with its main line, is provided with one ground.l IVhen a telephone or other circuit-indicating device is connected with this same test-circuit upon another board, the test-circuit will be completed through a telephonie or other circuit-indicating device. In all such systems the cross or connection of the mainline with the test-circuit is maintained during the entire time talking is going on. This has the effect to greatly increase the electro-static capacity of the talking-circuit, thereby reducing the margin for practical talking over a given circuit and adding to the cross-talk from and to other circuits which Inay be in use simultaneously.

One of the essential advantages of my invention over other n1ultiple-switeh-board systems is that when the test shall have been made and the plug inserted the test-circuit is closed directly to ground without contact or crossing between the test-wire and the Inain circuit during the time any given line may be used for talking. The test-circuit being closed directly to ground will contain less resistance than when grounded through the medium of the main line, and the test will be more positive and the danger of false tests arising from high static capacity is obviated. This trouble from cross-talk caused by the high static capacity of the test-wires when crossed with their telephone-lines has heretofore been a very serious obstacle to the satisfactory working of multiple-switch-board systems, not only on account of the confusion necessarily caused by the cross-talk, as above stated, but also on account of the capacity of the test-wires, since where the test-Wires have been quite long, a busy test has been falsely indicated when the test-Wire was not actually crossed with its telephone-line.

In Iny application, SerialNo. 254,029, filed November 2, 1887, I have shown a system of telephone-exchange in which the subscribers are arranged in pairs, so that the line of either one of the pair may be utilized as one side of a metallic circuit. The two single lines of any pair may be thus united to form a lnetallic circuit between either of a pair of stations and the central office.

My invention herein, in respect to the testcircuits, while designed more especially for such a system of metallic circuits, may ce IOO used in any system of metallic circuits or in a single-line system of multiple switch-boards and also in combined systems having part of the lines single and part metallic. My improvement in the spring-jack switches, as'will be readily understood, may be used in any system to which they are adapted.

Heretofore various test-circuits and dilferent forms of spring-jack switches have been employed. As to the prior state .of the art, reference is made to the following United States Letters Patent: No. 308,315, granted Milo Kellogg November 18, 1884, No. 356,425, granted Charles E. Scribner January 18, 1887, and No. 374,908, granted Charles E. Scribner December 13, 1887, application Iiled May 12,

In the practical working of telephone-exchanges it is important that the apparatus, and especially the spring-jack switches, be readily accessible for inspection or repairs.

vThe objects of my invention are, brieiiy stated, as follows: First, to provide springjack switches capable of doing the work required which will occupy the least possible 4space upon the boards; second, to provide a local test-circuit suitable more especially for metallic circuits, whereby troubles heretofore existing on account of crossing the test-wires with the telephone-lines and from the static capacity of the test-wires are obvated, and, third, my invention consists in certain details Vof construction and special circuit-connections hereinafter described and claimed.

My invention will be readily understood by reference to the accompanying drawings, in whichf vFigure l, Sheet l, is a front elevation of a strip of ten spring-jacks embodying my invention. Fig. 2 is a detailed sectional view of one of the spring-jacks on line m of Fig. 1. Fig. 3 is a rear perspective view showing the front portion of three spring-jacks removed. Fig. 4 is a detailed sectional view of a spring-jack, showing a loop-plug inserted therein. Fig. 5 is a plan showing several spring-jacks of a strip. Fig. 6 is a View from l -ators apparatus at the different boards forreceiving the calls and makingthe tests and Ih-onnections and transmitting the signals to the subscribers stations. Fig. 10, Sheet 3, shows asingle-line connection with a metallic circuit. Fig. 11 is a modified form of the spring-jack switch, in which the thimble or metallic socket is in two parts which are insulated from one another. The front portion serves as the test-piece. Fig. 12 is a sectional view of another modification of the springjack switch, in which the test-spring is permanently connected with a separate test-piece at the front. Fig. 13 is a sectional view showing a hole bored through the rubber frame of the switch, through which the wire which connects the test-spring with the test-plate is preferably run. l

I will first describe my spring-jack switch as illustrated on Figs. 1 to 8 of the drawings. In FigI have shown a strip of ten switches, and adjoining at opposite ends portions of two other strips. These spring -jacks `are built up upon rubber frames, the frames or rubber portion of each strip consisting of the front removable portion a., which carries the metallic socket a', and the rear portion b, on which are mounted the different springs of the spring-jacks. It ,will be observed that the sockets a are each provided with contact-points a2 and a3. These points are preferably of the form shown in Fig. 8, the horizontal extensions from the socket being preferably perforated, as indicated at a4, the perforations being bored out, preferably tapering upwardly, so as to permit any dust that might accumulate to work out away from the contact-points without clogging. The portion a-may be secured to the portion b by means of screws or in any other suitable manner, so

Vas to permit the front portion to be readily removed to make the points of the switches accessible, as shown in Fig. 7.

Each spring-jack I have provided with a line-terminal spring c', a corresponding insulated contact 02, the spring c3, with which the outgoing limb of a metallic circuit may be connected, and the spring c4,with which the test-wire may be connected, and under the test-springs I provide a ground-connection c5. The springs c and c3 and c4 are insulated from one another, and are so adjusted as to press normally inwardly. Between springs c and c3, Ipreferably place iieXible rubber or other insulating material, as shown in Figs. 2 and 6. The contacto2 is bored out, so as to admit a loose non-conducting pin c6. The line-sprin g c', re-enforced by spring c3, having a greater strength than the test-wire spring c4, will hold the said spring c4 up in contact with contact a2 of the .socket a', as shown in Fig. 2. The pin c? being forced up permits vthe spring c to close upon its normal contact c2, as shown. When aloop-plug is inserted in a spring-jack switch, as shown in Fig. 4, spring cwill be separated from its normal contact c2 and closed to the tip .of the plug. The force of spring -c having been removed from the pin c6, spring c4 will sep- -arate from its norm al contact with the socket and close upon the ground-strip c5.

.It will be observed that the spring c3 of a line-out is adjusted so as to normally press inwardly toward spring c', the rubber stud c7, between the springs 'c3 and c', however, keeping their free and movable-ends insulated. When spring c is separated from its IOO IIO

contact by the insertion of the plug, it is at the same time forced against the stud c7, and this moves spring c3 to close upon the point a3 of the socket a. Thus as spring cL is disconnected from the socket spring c3 is closed thereon, as shown in Fig. I. The plug being inserted in the socket, the metal sleeve of the plug will be closed to the socket, and hence to the spring c3. On removing` the plug the springs will resume the position shown in Fig. 2. Vhen in this position, if the tip of a plug be touched to the socket a', connection will be made between the tip and the test-spring. The socket a upon the face of the board is thus made to answer a double purpose. The object of these different connections and the advantage of making the front portion a removable will be more fully understood in connection with the description of the circuits.

In Fig. 9 the circuit of line-in d, may be traced-through a line-spring and its contactpoint of a switch on each of the boards, and from the contact-point of the switch on the last board through the listening-in springjack d of the line. Continuing then from the listening-in spring-jack, this circuit may be traced through the individual annunciator d2 of theline to the spring-lever of the groundin g-switch. A loop-plug being inserted in this switch, the spring d3 is closed to the tip of the plug and also to the contact (Z4.

- From this contact d* the circuit may be traced normally by wire d5 to ground contactfspring de. Thus a signal sent in over line d will pass over said line d, as traced through the switches on the different boards, the annunciator d2 to spring cl3 of the grounding springjack, and thence by contact (Z4 and wire d5 to ground-spring (7,6. Sending current to throw down shutter d2 is the first step in making a connection. The operator at board l, seeing the shutter fall, at once loops her telephone into the circuitof the calling subscribers line. I have for clearness shown a simple form ot cam-lever loop-key for doing this work.

The operator, by simply throwing up calnlever e to the position shown, loops the telephone into the circuit of the line, and at the saine time disconnects wire di from the ground-key d and closes said ground-key to the contact c of the test-wire of the callingline d. The test-wire circuit- I will describe in detail later. The operator thus, on seeing a shutter fall, throws up the cam-lever, and this brings her telephone into the circuit ot' the line, at the saine time putting on the busy test.

I will now trace the circuit thus formed through the operators telephone. Beginning at spring d3 of the grounding spring-jack, the circuit will pass through the tip of the loopplug, and thence by a strand f ot' the cord to a contact f'f2 of the loop-key, and thence by the wire f3 to calling-keyf, and thence by wire f5, through the telephone f, and by wire f7 to the other calling-key f8,and thence by wire ff to contact f 10 of the loop-key, with which the other strand f of the cord of loop-plugfis connected, this other strand f11 being connected with the sleeve fm of the loop-plug, as shown more clearly in Fig. 4. I have thus traced the circuit from the tip of plug f through the operators telephone f and back to the sleeve of the plug. I have heretofore traced the circuit of line-in (l to the tip of said plug, and have also shown how the ground is taken oit from wire d when the lever eis thrown up to bring the telephone into circuit. I have not, however, traced the circuit of the line-outthat is to say, the otherlimb or side of the metallic circuit of the calling' subscriber. Beginning, then, at the sleeve j"12 of the plug f, as shown inserted in the grounding springjack at board 1, I will trace the circuit of lineout as fellows; From the sleeve f12 to the metallic socket or contact of the switch to line t, and thence to the contact-spring ci; of the switch on the First board, and thence out to line. It will be observed that line g is branched over to spring ci" of the spring-jack switch of the line on board 2. I have thus shown how by a simple movement of thelever ot the loopswitch ot' a line the operator brings her telephone into circuit and closes the test-wire of the line to ground. I will now describe the test-wire and its connections in detail.

The test-wire 7L, it will be observed, is connected with thc test-spring c'l of each of the spring-jack switches ot the line on the diiferent boards and also with the contact 7L of the grounding springjack 0f the line. \Vhen cam-lever c is down in its normal position and no connection is made with the line at either of the boards, the test-wire h is open. If when thus open a ground-wire, including a battery and telephone, be connected to one testpiece or socket of the line, no current will pass through the telephone, and the operator listening at the telephone and hearing no sound will know that the line is free-that is, not connected with any other line or in process ot being connected. If, however, the test-wire be grounded at any otherpoint when the connection is made with a test-piece, the circuit will be completed and current will be sent through the telephone, and the operator listening will know that the line is busy.

I have provided a ground-connection c5 in connection with each spring-j ack, upon which the test-spring c4 closes when the plug is inserted in any spring-jack switch. Thus in Fig. 4 test-spring c4 is shown closed to groundstrip c5. This is a direct ground-connection, and the test-wire when connected to show the busy test is not crossed or connected with the line. The operator then, having looped her telephone into a calling subscribers metallic circuit and found out what other subscriber is wanted, withdraws her plug f from the grounding spring-jack and proceeds to test the line of the subscriber called for.

At board 2, Fig. 9, the operators plug 7i,

IOO

IIO

IIS

through the telephone f6 and wire branch 7c, which is connected through test-batwhich is the same as plug f at board l, is

Vshown withdrawnfro'm the grounding-'switch t" of its line. By touching the tip of plug f to the socket a of the switch of any line it A may be determined whether the line is busy.

If the test-wire of the line tested is grounded, a circuitwillv be formed through the tip of the plug and strand f to spring f2 of the loop-switch, and thence, as before traced, f7 to the tery k and condenser 702 to ground.

`In case theV line tested is found free, the operator will at once insert the plug finto the switch, and by depressing one of the callingkeys f8 or f4, as the case may be, sends current to line-wire m or n, as the case may be,

these wires being preferably grounded normally at the subscribers station. lIn case the AwireA h is closed to groundl by contact h',

spring d4, wire d5, and ground-contact d, Thus when two lines are connected both of their test-wires are connected to show the busy test,

each to a different ground-connection-that is to say, the test-wire of the calling-line will be closed to a ground-connection d and the test-wire of the called subscribers line will be closed to the ground-strip c5 of the switch in which the plug f of the calling subscriber is inserted. Thus if plug f were inserted in spring-jack switch 1 of metallic circuitjn n, test-wire 0 of said circuit would be closed t0 ground-stripe5 by test-spring c4 of said switch l. When yth us connected, a test made at switch p or q of either of the lines at any other board would indicate that the lines were busy. By means of a loop-plug yr connected with the operators telephone, as shown more clearly at board` 2, the operator may loop her telephone into circuit with the connected lines by inserting the said plug r into a sprin g-j ack s, provided for this purpose.

At board 2 I have shown a key t for closing the test-battery to the telephone, since it would be preferable on some accounts not to have the test-circuit permanently connected with the operators telephone.

In Fig. lO I have shown a single circuit u,

which is connected in the usual way through a different spring-jack switch on each of the multiple-boards and from the switch on the last board through a listenin g-in spring-j ack, l

loop-key, and thence by strand u2 of the flexible cord to the tip of the plug us. This plug w3 is shown inserted in a spring-jack a4 of another line. The line connected wit-h springjackv 11,4 may be either a single or a metallic circuit line. We may consider the springjack "a4 the same as the spring-jack p upon board 2, Fig. 9, and the connections may be considered as the same. The plug w3 being inserted'in spring-jack a4, the line-terminal is separated from its normal contact and closes upon the tip of theplug, as shown, and the metallic sleeve of the plug, as shown more clearly in Fig. 4, will be connected with the spring c3, through the medium of the metallic socket and the contact as. The return portion of the metallic circuit is connected, as heretofore described, with a spring c3 of each of the spring-jacks upon the different b'oards of theline. The springs c3 of the spring-jack switches of the line u, as shownV in Fig. 10, are connected together by a wire fu, which wire o, instead of returning to the subscribers station, is directlygrounded. Thus it will be seen that any plug us of a single-circuit line may be inserted, as shown, in spring-jack a4 of a metallic circuit, to loop together the metallic circuit and the single-line circuit. The loop-plug n.3 being inserted in spring-jack a4, loops the metallic circuit which may be connected with the spring-jack fw* to the different terminals of the plug as, and hence to the different strands of its IieXible cord.

The strand which connects with the loopplug a3 is connected with the spring a5 of the loop-switch. This spring ui", when in the position shown in Fig. l0, is connected with the wire o and the circuit may be traced through this wire Q; to ground, as shown at o. Thus when the circuit of the line u is connected with the metallic circuit the united circuit of the two lines may be traced from the ground at subscribers station of the line u through the spring-jack switch on each of the switchboards, through the listening-in spring-jack and the individual annunciator, which now serves as clearing-out annunciator to the lspring u of the loop-switch, and thence through a strand of the cord to the tip of the plug u, and thence over the'metallic circuit IIO connected with the spring-jack a4 back to the sleeve of the plugus, and thence through said strand of thecord to spring a5, and thence to wire o, and thence to ground.

The connection with the operators telephone and the test-circuits and listening-in apparatus may be the same with single lines as heretofore described with respect to metallic circuits., Thus the test-Wire w of the 4rsingle circuit u is connected in the same manner as the test-wires h of the metallic circuit d g, shown in Fig. 9. A

In Fig. 10 I have shown resistance zi in place of condenser k2 of Fig. 9. In the modification ofthe spring-jack shown in Fig. 11 the linespring l normally rests upon its contact 2. The front portion 3 of themetallic socket is IZO ` serted, spring c6 will be disconnected from portion 3 of the socket and closed upon groundconnection 5. The return portion of a metallic circuit may be connected with the rear portion of the metallic socket, this rear portion being, for convenience, preferably extended to the rear for connection therewith, as shown. A spring-jack of the form shown in Fig. ll might be made to occupyless space than any other form of spring-j ack with which I am familiar having connections sufficient to do the work required.

In the modification shown in Figs. l2 and 13, instead ofthe metallic socket, I have shown a separate contact-piece 7, placed over the socket and permanently connected with the test-spring (5. The connection between the test-spring G andthe test-plate 7 I preferably make through a hole boicd through the switch-frame, as illustrated in Fig. 13.

My invention admits of many other modications that will readily suggest themselves to those skilled in the art, and I therefore do not limit myself to the construction shown.

Having thus described my invention, I claim as new and desire to secure by Letters Patentl. A spring-jack switch consisting in the combination, with the tube, of two springs, which are interchangeably connected an d disconnected therefrom upon the insertion and withdrawal of the plug, and the line-terminal spring and its normal contact, substantially as described.

2. The combination, with the tubo or testpiece of a spring-jack switch, of the linespring resting upon its contact and two springs on opposite sides of said line-spring, and insulating material on opposite sides of said linespring, separating said line-spring from said other springs, respectively, and a loop-plug, which, on being inserted, separates the linespring from its normal contact, at the same time permitting one of the two outer springs to fall away from its connection with the tube while the other outer spring is closed thereto, substantially as described.

3. The combination, with the tube a', of the insulated springs c', c3, and c, the contact-point c2, against which spring c normally rests, the loose pin between springs c and c4, the ground-connection c5 for .spring c4, the spring c3 being insulated from spring c and adjusted to move therewith, and a plug which on being inserted separates spring c from its normal contact and permits spring c4 to separate from the tube and close upon its ground-contact c5, while at the same time spring c3 is forced into connection with said tube.

4. A strip of spring-jacks, each consisting of a socket with which two different springs are alternately connected and disconnected on the insertion of a plugyvthe portion of the strip containing said sockets being removable, substantially as described. Y

5. The socket a', provided with contactpoints a2 and a3, said contacts being extended to inclose springs on opposite sides of a springjack, in combination with said springs, and means for alternatelyconnecting and disconnecting said springs from said contacts.

O. A spring-j ack switch provided with alineterminal, the normal contact of said line-terminal, a test-spring insulated from said lineterminal, and a connection for the return portion of a circuit, in combination with the loop-plug inserted in said switch, whereby the line-spring is separated from its normal contact and closed to the tip of the plug, while at the same time the return-connection of the switch is closed to the sleeve of the plug.

7. A ground spring-jack switch consisting of the lever d3, permanently insulated from the connection 7i of said switch, a groundconnection d, and the insulated socket or frame, in combination with a loop-plug, which on being inserted separates ground-connection d" from connection 7L and closes connection d3 to said ground-connection d* while connection is made between the tip of the plug` and spring d3, and at the same time the sleeve of the loop-plug connected with the socket, substantially as described.

S. The loop-plug f and its terminals connected with springs f2 fw, respectively, said springs including in their circuit a telephone and a branch ground-connection 7a, including a test-battery, substantially as described.

9. Two metallic-circuit telephone-lines, each connected through different spring-j ack switches on two or more multiple switchboards and each provided with a loop-plug terminal and test-circuits, one for each line, each of said test-circuits being normally open, in combination with independent ground-connections for each of said test-circuits, with which ground-connections said test-circuits are closed automatically on the insertion of the loopplug terminal of one line into a springjack switch of the other line. l

10. A telephone-line connected through the line terminal and contact of two or more switches on different switch-boards and thence through an annunciator, and thence normally through a grounding-switch to ground, in combination with a return-wire connected witha spring of each of the spring-jack switches of said line, and with the grounding-switch, an independent test-wire for said line connected with another spring of each of the spring-jack switches of the line and with a contact of the grounding-switch, and direct ground-connections, one for the test-wire spring of each of the spring -jack switches and one for the grounding-switch, whereby a signal may be sent over the line to throw down the annunciator and a test-circuit provided, the circuit IOO IIO

of which is provided with a direct ground-connection when the telephone-line is connected with another line.

11. The combination, with two telephonelines connected together, of separate local testwires, one for each ofA said lines, said telephone-lines being each connected with springjack switches on different` multiple switchboards, and the test-wires being connected with each of the spring-jack switchesof their lines, respectively, and a direct ground-connection c5 for each of the spring-j ack switches,

whereby each of said test-wires is provided with a different direct ground-connection independent of any portion of said telephonelines when the two lines are connected, substantially as described.

l2. In a multiple-switch-board system, a

test-wire normally connected with a test-piece of each of the switches of a telephone-line, in combination with e. special direct ground-contact 0n each of the springjack switches, whereby on making connection with said line at either switch said test-wire is disconnected from saidtest-piece and closed to the special direct ground contact of the springjack switch at which the connection is made.

13. In a. multiple-switchboard system of telephone-exchange, two telephone-line circuits provided with spring-jack switches, a. separate spring-jack switch being provided for each line on each boa.1d,in combination with the testecircuits, a. separate test-circuit being provided for each telephone-line, the test-circuit of each line being connected with a special test piece or spring of each of the switches of its line and a direct ground-connection near each special test-connection, said direct ground-connections bein gindependent of any portion of the telephone-lines, and plugs at the dierentswitch-boards, whereby on inserting a plug in any switch the special test-connection of the switch will be closed directly to ground without closing or connecting the test-wire with the main-circuit line. 45

In Witness whereof I hereunto subscribe my name this 23d day of November, A. D. 1887.

FRANKLIN G. REACH.

Witnesses:

GEORGE P. BARTON, HENRY W. PROUTY.

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