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Publication numberUS972329 A
Publication typeGrant
Publication dateOct 11, 1910
Filing dateJul 9, 1906
Priority dateJul 9, 1906
Publication numberUS 972329 A, US 972329A, US-A-972329, US972329 A, US972329A
InventorsWilliam M Bruce Jr
Original AssigneeAmerican Automatic Telephone Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Lock-out device for party-line telephones.
US 972329 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)



e a, as W&% 5mm 5 W. M. BRUCE, JR.



Patented Oct. 11, 1910.







To all whom it may concmi:

Be it known that I, WILLIAM M. BRUCE,

J r., a citizen of the'United States, residin necessity of fine adjustment.

L Generally speaking, the system includes a;

relay at the .subscribers station which is adapted when the telephone is removed,

from the hook to be bridged across the line,

' and by its operation to switch into the circuit the subscribers talking outfit, the con struction being such that the talki'n instruments and the said relay will utllize "the current flowing on the line so that the relay at another stationwould not be operated so long as the telephone hook or-main operating switch at one subscribers station is in operative position.

devices of this character, it has been found that where the stations are placed at lon distances apart the line resistance is suc that a more or less fine adjustment of' .the relay is necessary, depending upon the location of the stations in relation to the exchange, as where one station is close to the exchange and one a long distance therefrom the diflerence in the line resistance will causethe relays to work with more or less efliciency, so that an adjustment to its location on the line is necessary. It has also been the practice where it is desiredtobonn'ect two subscribers on the same line to employ a condenser through which the talkin .'currents of one subscriber might pass while the battery currents are held back, --thus permit- {ing a second relay to operate on the same By the improvement. herein described, I

also obviate the use of the condenser to es- Specification of Letters Patent; Application filed Jul 9, 1906. Serial 170.8%,210.

Patented Oct. 11,1910.

tablish connections between subscribers on the same line.

The invention consists in the system and means hereinafter described and pointed out in the claims.

In the accompanying drawings, Figure 1 is a'diagram'matic view showing a common battery exchange and two subscribers stationsl Fig. 2 is a diagrammatic View of one jsubscr-ibers station showing a modification of a part of the device. I

In said drawings, A represents a common battery located at the exchange, and B and C subscribers stations.

D and D are opposite sides of the line i which connect the several subscribers (any number of which may be connected) to the exchange.

a, is the ordinary telephone hook or switch adapted-to be operated-when the receiver is removed. I

b is the receiver, 0 the transmitter and d the induction coil, which parts constitute the usual subscribers talking outfit.

be bri ged across the line b theoperation of the main telephone SWltCl WllBIl the re ceiver is removed therefrom through the relay is constructed in two parts, e e normally in series and representing preferably about sixteen hundred ohms, one art being preferably of about one thousand ohms resistance, and the other six hundred ohms resistance. When the telephone is bridged across the line the sixteen hundred ohms of this relay are in circuit through the circuit 1,

1', 1, 1 above mentioned.- This very high resistance produces a relay that will operate on any reasonable-length of line, but by reason of its high resistance it has not the magnetic ull of a relay of lower resistance. I, therere, provide means forcutting o t a a of this resistance as soon as the relay operates, which it does immediately uponthe closin of thecircuit 1 at the main switch, a, as 'llows: The magnetic influencein the relay produced by current passing through 6 represents a relay which is adapted to circuit 1, 1, 1, l. The magnetic coil of this sixteen hundred ohms operates the switch e, which establishes two circuits one of which passes from the circuit, 1, through the switch, the subscribers talking instruments, 0 and (Z, to the line, D The other circuit passes e and through circuit 2 through from the switch, e and circuit, 1, through tent as to Subscribe .1111 connection with this device, in the diacircuit, 3, to the main part of the magnetic coil of the relay forming a short circuit around that 'part of the coil having the lowest resistance, and thus cutting out the lower resistance and leaving the coil at the proper resistance to furnish the necessary working 'power'in'the relay and also, in connection with the talking instrument,-touse the current passing across the line to such an exprevent the operation of any other g'rammatie'viewj herein shown, I have not includedany ringing circuit, as any wellknown; ringing circuit, either selective or otherwise, may be employed in connection with the improvement herein described.

The operation as thus far. described is as follows: Any subscriber being called f'by a proper signaling device removes his telephone from the hook, and by such removal said relay, firmly holdin its operatlve position, an at the same time establishes a bridge across the line through the circuit 1, and the entire resistance constituting the magnetic coil of the relay. The energizing of the magnetic coil of the relay produced by the current flowih through the same, will operate the switc a and thus cut in thesubscriberstalking outfit through the circuit, 2, and at the same time cut out the'resistance of the part, 6 of the energizing coils of the relay and thus allow a greater amount'of current to pass through utilizing the current to such an extent that the relay at no other station on the line canbe operated, even though its main telephone switch should be operated by the removal of the receiver.

To provide for connecting two subscribers on the same line, I provide in the circuit, 2,-

a circuit breaker, f, adapted when operated to break the circuit, 2, including the talking instruments, thus cutting out the 'subscribers talking outfit, without interfering with the circuit 1, through the relay, and establishing another circuit, 4, of purely local character which passes through a coil, e, in proximity to thelenergizing coil, a of'the relay, and thence through the relay switch,

6 and apart of circuit 2, through the induction/coil, (l, of the subscribers outfit.

This circuit it will be seen does not extend across the line and gets no current except such as may come by induction from the energizing coils .of the relay. In this condition, the subscriber desiring to talk with another subscriber on the line, signals the exchange in the usual way and havlng given his call presses the button to operate the switch, f, cutting out his talking instruments from the line and establishing a local circuit through the inductive coil, 6 and the primary of the induction coil of his talkthe switch, 6 ml ing circuit. The coil, c of the relay remaining in the bridge across the line will' receive any talking'currents passing across ,the lines D D- by reason of the bridge across the same,- and such alternating talking currents will induce a current in the coil, 6, which currents by. reason of the local circuit established by the switch, 6 will be carried to the primary of the induction coil of the local receiver and thus ermit the subscriber' to hear what is said on the line, although said instruments arecut out from the bridge across the line.. As soon as the connection is made with the other subscriber, which the first subscriber will know by the conversation, the switch "f is released and the subscribers outfit is again brought into circuit with the other subscriber also on the line. It will be understood in this connection that whilethe current on the line would not be sufiicient tooperate a relay at a subscribers station when-the relay and.

talking instruments of another subscriber are in circuit, yet after the relay is operated the-current passingthrough the same will be sufiicient to. holdthe relay and switch in operated position and thus maintain a circuit'after the same has been established with two subscribers on the line.

In Fig. 2 I have shown a modification in which the coil, (2*, instead of being placed aboutthe core and thus forming a part of the energizing coil of the relay magnet is placed in series with the relay magnet but separate therefrom. In'this case a coil of lower resistance will preferably be used and will act as a feeding coil to the relay coil, thus limiting the amount of current that will ,pass to the energizing coil in the event that the voltage should be somewhat higher by reasonofless' line resistance. This arrangement'of the coils will materally reduce the fine adjustment required in placing the sub scribers stations at greater or less distance from the exchange,'and has been found to be effective, although the preferable way is to put this feeding coil in series with the main energizing coil on the magnet itself, in which case both coils act as energizing coils when. the instrument is first operated. In

either case, the first or feeding, coil will be cutout as soon as the switch is operated to establish the main talking circuit.

It will be seen that by the construction and thus provide a system which forms a emcee i the line when ordinarily used, and at 'the same time by the use of the relay switch to establish alocal inductive circuit which will enable the subscriber to hear although his talking outfit is cutout of the line circuit, so as to permit another subscriber on the same line to be brought into the circuit by the operation of his relay.

lin constructing the relay, 1 preferably Wind the coils, 6 c e upon the same spool,

though. they may be otherwise formed so long as thecoil, cf, is in sumcient proximity to the energizing coil to obtain the inductive influence. Y H; Having thus described my invention, 1 claim: j l. ltn a party line telephone system, a series of subscribers stations each having a normally inoperative talking outfit, and a relay to bring said talking outfit into circuit,

the relay at each subscribers station having an inductive circuit including talking instruments independent of the line circuits, and means for disconnecting said talking circuit tromvthe line with therelay in circuit with said line, substantially as specified.

2. The combination at'a subscribers sta tion of a disconnected talking outfit, a relay to establish afcircuit through said talking outfit, an inductive circuit through the relay. and said talking outfit independent of the line circuit, means for breaking the line' circuit through said talking outfit and at the same time establishing the inductive circuit L through said talking outfit independent of the line circuit.

8. ln a party line telephonelockout sys-. tem, a relay coil, resistance in series With said relay coil, an inductive coil in proximity to said relay coil, means for cutting out. v

local circuit through the inductive coil cuit is broken said resistance, and'means for establishing a Y the subscribers talking outfit, substantiallyas and for the purpesespeoified.

at. In a lockoutior party line telephone system,.a main switch, a relay adapted to'be bridged across the line by'the operation of saidswitch, a talking outfit adapted to be brought into circuit bythe operation of the relay, a circuit breaker 'to disconnect said talking-outfit independentof said relay, "and I a local inductivecircuit through said relay said inductive circuit when the talking cirspecified. l

said relay, and a local inductivecircuit through the talking instruments adapted to receive inductivecurrents from thecoil of and talking outfit, and means for establishing b5 7 by said circuit breaker, as

said relay, and means for opening and closing said inductive circuit, for the purpose specified. or V. v 1

6. lln a lockout device, a relay coil, re sistance in series with'said relay coil, and an inductive coil in proximity to said relay coil, 'a switch operated by. the relay to es tablish a talking circuit, means for cutting out said resistance by, the operation of the switch, and means independentof said relay for breaking said talking circuit and establishing a local circuit through the inductive coil and talking instruments, as specified In testimony whereof, I have hereunto set my hand this third day of July A. D. I906.

WrLL'ni M. canon, at.


WM. F. HOFFMANN, H. H. Hornms.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5386463 *Nov 17, 1992Jan 31, 1995Kings Iii Of America, Inc., North AmericaLow noise multi-elevator communication system and method
Cooperative ClassificationH04M1/70