US393612A - beown - Google Patents

Description

UNITED STATES PATENT OFFICE.

CHARLES W. BROWN, OF MONTREAL, QUEBEC, CANADA, ASSIGNOR TO THE BELL TELEPHONE COMPANY OF CANADA, OF SAME PLACE.

TELEPl-IONE- SYSTEM.

SPECFICATION forming part of Letters Patent No. 393,612, dated November 27, 1888.

Application led March 31, 1888. Serial No. 269.211. (No model.) Patented in Canada Api-i116, 1888, No. 28,932.

To @ZZ whom it may concern:

Be it known that I, CHARLES WARREN BROWN, of the city of Montreal, in the district of Montreal and Province of Quebec, Canada,

have invented certain new and useful Improvements in Telephone Systems, (for which Letters Patent of Canada, No. 28,932,were granted to me on the 16th of April, 1888;) and I. do

hereby declare that the following is a full, 1o clear, and exact description of the same.

The system to which my invention applies is that which has been adopted forlarge buildings to secure telephonie communication between the numerous departments therein.

Such a system is shown anddescribed in Patent No. 356,427, granted to C. E. Scribner, and which he calls a Factory Telephone EX- change, but which can also be styled a local system. Such systems consist, essen- 20 tially,of a separate instrument for each department, embraeinga key-board and plug,a callbell, transmitter, battery, and telephone, and the necessary connections. In addition to its adaptability to large buildings, such a system can also be used for local com municaton,such as between a main building or department and outbuildings in immediate vicinity, and also for village telephonie communication, if desired. In all such cases, however, for outside 3o work or communication with another system a separate and distinct general telephone is required, and of course to this all parties in the building or community must come to hold communication with the exchange and outsiders.

The purpose of my invention is to do away with this-general telephone altogether and give to each department or station in such local system separate connection with the eX- change, in addition to their present power of speaking to any other department, and obviously allow exchange to call either of the departments. This object I attain by certain alterations in and additions to the mechanism for local communication above alluded to, which changes will now be brieliy described.

I have separate instruments for each department, each of which includes, first, a keyboard and plug, the sameas before, except 5o that an exchange `key and push-button are added; second, a call-bell, the same as formerly, for signaling between the departments only; third, a transmitter differing from. ordinary construction in so far that its battery has a complete circuit separate from the sec- 5 5 ondary circuit of the induction-coil; fourth, a telephone the same as formerly; fifth, a system of insulated springs operated by the telephone-lever to cut telephone iny and out and to open and close the separate transmitter-battery circuit, also serving to keep closed the exchangecircuit, in which are arranged extension-bells to allow the exchange to call any particular department by special signal. In addition to these instruments I have a main or` calling battery common to all of them, instead of an independent battery for each. Besides this the arrangement of the line connections and the foregoing mechanism is such as will enable one station,as formerly,to call another without calling other stations in the system, and also to allow any department to call the exchange without calling the other stations. Further, the arrangement renders possible a test as to whether the local circuit of each station is clear by each station without calling other stations, and provides means, in connection with the exchange-key, for calling the eX- change, and a push-button whereby the eX- change speaking-circuit is closed. For full comprehension, however, of the invention reference must be had to the annexed drawings, in Which- Figure l is a diagram of a system comprising three stations, two of which are shown in communication,the telephones being removed fromv their hooks or switch-levers, and the third in its normal position; Fig. 2,a sectional detail of thekey-board, the section being taken so as to show the particular key for calling the exchange and the push-button for keeping the talking-circuit from same closed; and Fig. 3 is a detail of a pair of insulated springs on the eX- change-line operated by the telephone-lever to keep same always closed, so that the eXtension-bclls can be rung at any time.

`Similar letters of reference indicate like parts.

As all the parts or mechanism of the system are well known to those skilled in the art to which this invention appertains, it is not considered necessary to illustrate them other- ICO wise than by diagram. lt must also be understood that while the outtit of only three stations or departments is shown any number may be included in the system.

Referring to Fig. l, I showin diagram in the stations Nos. l, 2, and 3 the several parts or elements of an outtt, all of which, except the extension-bell, will of course be mounted on a board of the usual kind and arranged upon the wall. The extension bell will by preference be placed out ot' the way upon some convenient shelf.

A represents the key boards,eaeh composed ot' t'our keys, a/ It La a, ot' the kind shown in section in Fig. 2-vi7.., a metal base or stud with a central plug-hole and a projecting [lat metal spring to be depressed, so as to make contact with the united terminals b' b Il b of wires n," ai w from one pole of the main or calling battery X, which is com mon to all the stations and situated in any convenient partofthe building.

a' a a are the calling-keys of each station in the system, and a is to call the exchange. The connections between the keys of the several stations are made by wires cc'fcias shown. An additional key,a", l'or closing the exchange talking-circuit, is provided, and consists of a lat metal spring, a", projecting from the opposite side of the stud ot` key rt* and provided with a button or more convenient means-such as a hand cam-lever-acting on its free end t'or holding it depressed (while talking is going on) upon a terminal at end of a terminal wire, b5, ofthe secondaryeircuit ofthe transmittercoil, so as to leave one of the speakers hands free in ease he should want to write down a message. As these several keys are normally out ot` contact with the several terminals and the circuit naturally broken, and as it is of course necessary that the exchange-circuit shall always be closed in order to ring the extensionbells at any time, I arrange a bridge, b", over the spring ot key a, and by means ot' this bridge and a screw set in same and bearing upon the spring a permanently-closed exchange-circuit is secured, as the exchangeline e* is carried into the station No. lY and connected, first, with the stud of exchangecalling key a, whence the circuit continues, through spring a, screw, and bridge b,toa continuation ofthe exchange-line. This continuation leads from bridgeb of station No. l to exchange-calling key a* and bridgeb"of station No. 2, and so on through a furthercontinuation of the line to the same parts in station No. 3, a closed circuit being maintained throughout all these parts. From the bridge in the last, or No. il, station the exchangeline is carried back to No. l, where it is divided in two and terminates in two springs, de, one on each side ot the switch-arm ot` the telephone-hook ll, but never coming in contact with it. Similar springs, d c', forming the terminals of the divided end ofa continuation, c, ofthe exchangeline, on which the extension-bell E of station No. l is arranged, are furnished with knobs d'2 c2, of insulating material, which come in contact with the switcharm, but of course have no electrical connection with it, and arc acted upon by it to canse the respective pairs of springs Z d and c c to make electrical contact. These springs are t'or the purpose of maintaining an unbroken exchange-circuit at this point whether the telephone be on the hook or ott', and this is done when the telephone is on the hook bythe switch-arm, as shown in No. 3 station, pressing spring e into contact with spring c, and when the telephone is ot't`, as shown in stations Nos. 1 or 2, by the contact of (t and ft. rlhis duplicate arrangementot'springs is provided in each station, as shown, and it will be seen that the unbroken circuit passes through all the extension-bells E t0 ground.

Anystation (say No. 3) can call the exchange without calling other stations by pressing key a", which closes t-he break bctnveen exchange line and main calling-battery X, and the current travels 'um the exchangedines between the several stations and through the bridges b, springs a, and their studs in stations Nos. 2 and 1 to exchange.

F l Fiare the caltbells of each station, and l. N the bindingposts of same, one, l?, of which is connected by wire p topositive pole or earth line ot battery X, and the other by wire n to thetelephonehooks,which,whenthetelephone is hung ou either 0l' them, make electrical contact with either ol' the springs n' nf" a, a' forming the terminal of calling-key wire c, 11F' the same of branch c' from calling-wire c, and n" the same of branch 0 from calling-wire c.

Suppose No. 3 desires to call No. l, whose instrument we will presume is in its normal condition, the same as No. 3. No. presscs key Land the current travels along wire c to spring n', through telephone-hook, along wire n, to call-bell F, and through same to earth by line p, this being done without calling No. 2 in any way; and, again, if No. 3 desires to test his callbell to see it his own circuit is clear, he will press the key of his own station (marked 3) and make a battery-circuit from pole or terminal t", up line c, down its branch 0", and back to key 3 by spring or", telephone-hook, wire a, through call-bell F, and by Wire p to opposite pole ot` battery or earth-line. It will be seen that no other station is called during this operation.

All the parts of the instruments are normally in the position shown in No. 3 station, the telephone hanging on the hook and its switch arm keeping the exchange circuit closed by operating upon springs e c', and the call-bell circuit in the same state by switclr arm bearing against spring n 1" l* l3 are the transmitters,of ordinary construction, savc that I make its battery-circuit complete without becoming a part of the secondary circuit of the induction-coil.

t t'' represent the terminals of this complete ICO battery-circuit in the form of springs similar to those in the exchange-circuit and arranged on one side of the switch-arm, one, t', being always out of contact with the arm, but the other, t, insulated fomit by a knob, of rubber or other material, being operated by it when the telephone is removed to close the break between them and so work thc circuit.

S S2 S3 represent the telephones with their terminals connected, respectively, to earthlines and to one terminal, s, of the secondary eoil of the transmitter, while a plug, z, is connected to the opposite transmitter terminalwire, b5

After calling any particular station by depressingthe necessary key, the party calling inserts plug z in the plug-hole in the stud of that key, and as the party called also inserts his plug in the key bearing the number of his own station telephonie communication is established, as shown, between stations Nos. l and 2, the telephone being of course off the hooks. The speaking circuit between these two stations is from ground terminal of and through telephone S', along terminal s of and through secondary coil of transmitter, along terminal b, through plug a to key marked l, whence it follows Wire c to key l in station No. 2 and takes a corresponding course from this point through transmitter and telephone to ground.

l. The ombination, with a local telephone system in which each station can call andcommunicate directly with another independently of any special station or centralizing point to which the line of each station must converge, of a line-connection or closed circuit from an outside exchange entering each station, a signaling device (such as an extension-bell, E) in each station with which said line-connection is always in closed circuit except when either of the stations is in talking circuit with ceutral station, so that central can call any subscriber by special signal, a key in each station to enable it to connect a calling-battery circuit Vwith said line-connection or closed circuit, so

as to call such outside exchange, and meanssuch as a key-in each station for connecting its telephone-circuit with the said lineconnec tion or closed circuit, all as herein set forth.

2. In the individual station of a local telephone system, the combination of an individual local circuit-closing key or terminal of such station, a terminal of one pole of a main battery-circuit, and a circuit confined to such station connecting such calling-key through springcontact and telephone-hook with one terminal ot' an electro-magnet for operating callbell, the other terminal of the magnet leading to the other pole of said battery-circuit or to ground, all arranged and operating in the individual station, as herein described.

The combination, in a telephone system of a central-exchange ofiice,of a local system in which each station can call and communicate directly with another independently of any special station or centralizing point to which the line of each station must converge, and a line-connection or closed circuit from the exchange entering each station in local system and composed of main line leading to iirst station in local system, extensionflines between each station connected at stations by devices adapted to open and close circuit,and further extension-lines between each stat-ion and to ground carrying signaling devices, the pairs of springs d d and c e in each station of the local system connected with said further extensionlines', and means for securing contact of each of said pairs, as and for the purpose described.

C. XV. BROVN.

itnesses:

Fans. HY. RnYNoLDs, WM. P. MoFEAfr.

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