US767573A - Party-line ringing device for telephone-switchboard circuits. - Google Patents

Description

No. 767,573. PATENTED AUG. 16, 1904. J. W. LATTIG & G. L. GOODRUM. PARTY LINE RINGING DEVICE FOR TELEPHONE SWITGHBO'ARD GIRGUITS.

APPLICATION FILED JUNE 6, 1903. N0 MODEL.

N a L vn Zfiwsses.

UNITED STATES Patented August 16, 1904.

PATENT OFFICE.

JACOB W. LATTIG, OF WEST BETHLEHEM, AND CHARLES LANE GOODRUM,

. OF PHILADELPHIA, PENNSYLVANIA, ASSIGNORS TO EASTERN TELE- PHONE MANUFACTURING COMPANY, OF VIIESTCHESTER, PENNSYLVA- NIA, A CORPORATION OF PENNSYLVANIA.

PARTY-LINE RINGING DEVICE FOR TELEPHONE-SWITCHBOARD CIRCUITS.

SPECIFICATION forming part of Letters Patent No. 767,573, dated August 16, 1904. Application filed June 6, 1903. Serial No. 160,325. (No model.)

'To all whom, it may concern.-

Be it known that we, JAooB LATTIG, residing in West Bethlehem, Lehigh county, and CHARLEs LANE GrooDRUM, residing in Philadelphia, county of Philadelphia, Pennsylvania, citizens of the United States, have jointly invented a new and useful Party-Line Ringing Device for Telephone-Switchboard Circuits, of which the following is a specification. I

Our invention relates to party-line ringingkey apparatus and circuits, having particular reference to those systems in which the subscribers ringers are connected to the two limbs of the line, so that by sending ringing current of proper polarity over one limb or the other or both simultaneously any one bell or ringer may beactuated to the exclusion of others. Such-systems are currently denominated two-party selective, fourparty selective, and so on, according to the number of stations on a line. The simplest example of a selective party-line of this type is one to which two stations are connected, each of which has its bell or ringer normally included from one limb'of the line to ground, so that by putting a grounded generator to one side of line at central it will call one station and by putting it to the other side of line it will call the other station, using ordinary alternating current. By employing pulsating currents four substations may be connected in the same way, two stations having their ringers connected to one side of the line and two to the other, so that positive or negative pulsating current thrown on either side will actuate the ringer on that side only which is biased to respond thereto. In systems of this kind it is customary to employ at the 4 central oflice a selective ringing-key having a movable part or parts adapted to be set by the operator to the number or letter of the station to be called, the generator being then automatically connected in proper relation with the cord-conductors without further thought on the part of the operator.

Some

times this selective key connects the generator directly to the circuits and sometimes in proper relation to the contacts of an ordinary ringing-key. The latter is the best practice, 5 for if the selective key be arranged to normally connect the generator in given relation such stations as can thereby be called require only the use of the ordinary ringing-key, and the selective key need only be moved for a fractional number of calls. With such an arrangement, however,- a difficulty often arises in that the selective key may be moved while a ringing-key is downas, for instance, to make another callthereby causing confu- 6O sion, and in case the selective key is constructed to remain set a failure to restore it to normal position may cause confusion in subsequent calls.

It is the object of our invention to meet the 5 above objections and while retaining the convenience of the double-key arrangement to render it impossible for any confusion to arise in the joint or separate use of the keys.

We attain our object by making the selec- 7 tive key automatic in its return to one given position, but permitting its movement either to or from such position only when the ordinary ringing key or keys are in an inoperative position. In other Words, we look our selective key in whatever position it may occupy when a ringing-key is down.

In arranging our apparatus on a switchboard each cord circuit is .fitted with the ordinary ringing-key, which for convenience 30 we will hereinafter designate by the term ringing-key. In addition to these each operator is provided with a selective key connected to the ringing-keys, and this we shall hereinafter denominate the master-key, be- 5 cause primarily it controls the disposition of the ringing-circuits. Obviously there may be several of these master-keys for each operator, if desired; but as this would involve mere multiplication of parts our description 9 will be limited to one. If there are several, each would be appropriated to its own group of cords by preference. Each master-key is provided with a lock, and before it can'be set or unset it must be unlocked by having the cords clear or, in other words, all ringingkeys thrown up.

Our invention is fully described hereinafter and is illustrated in the accompanying drawing, wherein the same letters and figures of reference point out the same parts throughout.

In the drawings, Figure l is a diagram of a system embodying our invention, showing central-oifice cord-circuits and line-terminals, with two lines leading to substations. Fig. 2 is a similar diagram of a cord-circuit embodying the preferred form of our apparatus and connections.

Referring to Fig. 1, 1 2 and 3 4 are two subscribers lines entering a central station and there provided with suitable terminal jacks J and J. Each line is also provided with a line-relay L, controlling the local circuit of a lamp-signal 1, and its two limbs pass through impedance-coils I and I to the busbars 5 and 6 of a main battery M. The line 1 2 is shown passing to a single substation A, having the usual apparatus comprising transmitter T, receiver R, ringer Q, condenser C, and switch-hook H.

The line 3 4 is shown passing to two substations B and X. Each of these has the same apparatus as station A, and it will be noticed that the ringer at station B is to ground from the line-wire 4, that at X from the line-wire 3, and that at A from the line-wire 2. In such a system there may also be stations connected to separate individual lines and having their ringers bridged across the metallic circuit without any ground.

At the central office we show a cord-circuit 7 8 9 10 havingterminal plugs P and P, the former for answering calls and the latter for making them. When one of these plugs is inserted in the spring-jack, it forces together a pair of contactsjj to short-circuit the linerelay L, whereby the line-signal may be retired. Each plug is supposed to have associated with it a suitable supervisory signal and each cord to have a listening-key with connections to an operators telephone. This we have not shown, for it forms no part of our invention and would only complicate the drawings. I

The operation of the system thus far described may bebriefly stated asfollows: Suppose subscriber A calls by taking down his receiver. Current from the main battery M sets the line-signal 1 by its relay L. The in sertion of the answering-plug P closes the shunt about the line-relay and restores the signal. Having obtained the number wanted, the operator inserts calling-plug I in jack J (supposing 3 4 to be the wanted line) and by means of the ringing-key K calls up the sub scriber Wanted, which may be either B or X, according to the position of the master-key.

WVhen the subscribers have finished talking, they hang up and the operator clears out in the ordinary way. This brings us to the means by which B or X may be differentiated and the interlocking connections wherein lies our invention. For the sake of simplicity we will first describe the apparatus in Fig. 2, which shows a cord-circuit that might well have been used in the operation described. In this cord-circuit the conductor 7 8 passes through the normally closed contacts 12 13 of the ringing-key K and the conductor 9 10 passes throughthe similar normally closed contact 14 15. The contacts 12 and 15 are in the shape of springs having a bend toward each other and adapted to beseparated by the plunger of the key when depressed. On the outside of these springs lie a pair of contacts 11 and 16, connected, respectively, by wires 35 and 34 to the outer spring-contacts 23 and 24 of the master-key K. Mechanically connected to the spring 15, but electrically insulated therefrom, is a spring 17, normally apart from but adapted to be forced by the motion of spring 15 into contact with a contact 18. These springs 17 and 18 are the terminals of a circuit 28 27, including a battery M (usually the main battery) and the locking-magnet N. It will be understood that the springs 11 12 13 14 15 16 17 18 are supported in practice upon a block of insulation such as that shown at 71; for the master-key in both figures.

The master-key K comprises a pivoted hub 7r, carrying a handle k and a block of insulation and having a long arm 70 and a short arm 70* extending out on either side. The former is the locking-arm and the latter serves for the attachment of a suitable retractile spring which normally draws it down and throws the block of insulation 7t" to the left, as shown. In a notch formed in the lower face of the block 71: rests the upper end of a spring 21, supported at its lower end, as are also the springs 23 and 24, by insulation F, and this spring 21 is connected by wire 30 to the ringing-generator G, which on the other side is to ground by wire 32. It will be observed that if the handle 70 is left in the position shown the circuit of this generator is complete from the ground by way of wires 32 and 30, springs 21 and 24, and Wire 34 to contact 16 of the ringing-key, and when the plunger of the latter is depressed this circuit will be continued by contact between 16 and 15 through conductor 10 to the sleeve of the plugP, and if that plug is in a jack J through the sleeve of the jack to wire 3, and thence to ground through ringerQat station X. This is the normal path of current when the master-key is not disturbed, it being held in the position shown by its spring and returned to that position by the spring when moved. Thus when it is desired to call any station whose ringer is connected on the sleeve side of line the operator need manipulate the ringing-key K only. The advantage of this arrangement will appear after a moments consideration. change that it is desired to have every line uniform at the outset, but capable of having additional stations connected when required. In such case all the station ringers are put to ground from the sleeve side of line, and to call hold the same down. -w1ll remain locked as long as the key K is any of them requires only the ringing-key K. Suppose now in the course of events that ten per cent. of the lines carry two parties each. At first glance it would appear that the operator must punch a selective key for ten per cent. of her calls, and in the ordinary system this would be so; but in the present case it is not, for one-half of the parties on these lines being connected on the sleeve side are called uniformly with the rest of the exchange. Hence selection will have to be made in only five per cent, supposing the call-load to be uniformly distributed,which itis not. By taking those parties who receive the fewest calls and always putting them on the tip side, putting the busiest phones on the sleeve side, a manager may reduce the percentage to anything from one per cent. up.

If it is desired to call station B, still using the cord-circuit of Fig. 2, the operator throws over the handle to the left, whereby the spring 21 is moved to the right, breaking contact with spring 24 and making it with spring 23. The generator is thus shifted onto the mainspring 11 of the ringing keylK, the actuation of which connects the generator through conductor 8 with the tip of plug P, and if that is in a jack thence to line-wire 4 and through the ringer at station B to ground.

Whenever the plunger of key K is depressed, the contacts 17 18 are put together and the circuit 27 28 is closed, energizing the magnet M. This pulls down its armature a, which forms part of a bell-crank lever N, pivoted at a and carrying at its upper end a projecting detent-finger of. This finger engages with the arm 70 when the armature n is attracted, but is normally drawn back away from the arm by a suitable retractile spring. Thus when the lever F has been shifted over and the ringing-key K has been depressed the bell-crank N swings about its pivot, 'so that the finger n engages over the arm k to Obviously the key K down, and while this is a convenienceto the operator,'in that it saves her from having to hold the master-key, it is also a safeguard, for if she attempts to make a second selection too rapidly before the ringingkey on the first call is released she finds herself locked out, being restricted to one call at a time. It might be objected that with the master-key looked a false call might be unwittingly sentover the tip side of another line when intended for the normal sleeve side. This is really not a valid objection, however, for as there is only one master-key it can Suppose in an ex be made quite conspicuous, so that if it, remains in an abnormal position it serves as an almost infallible reminder to the operator of the condition of some one of her numerous ringing-keys. In this connection it may be stated that the springs 23 and 24 of the master-key are connected to the springs 11 and 16 of all the ringing-keys in parallel, as indicated by the short ends of lines attached to the springs.

If, as will mostly be the case, a call is sent with the master-key in the position shown in the drawings, the finger n will be pulled over as soon as key K is used, hooking under the arm k and keeping the same up until the ringing-key is restored. This prevents the throwing over of the master-key during normal ringing. If the master-key is thrown over for a call on the tip side, however, it will be obvious that not only will the operator not have to hold it over while sherings, but as soon as she restores the ringing-key to normal the master-key will spring back automatically to its own normal position, being released by the retraction of'armature a due to the breaking-of local circuit 27 28.

Referring now to Fig. 1 entirely, we have shown in that figure a cord-circuit and ringing-circuits adapted for use with metallic circuits with ringers bridged, as well as those having the ringers to ground. It might well happen that in some cases or in most cases in an exchange the single-line subscribcrs that is, those having but one instrument on a line-- should have no grounds and their ringers should be bridged. In this case the plugs, cords, and ringing-key K are precisely the same as in Fig. 2. The generator, however, has two wires 30 and 31, connecting it to contacts 21 and 25 and 22 and 26 of the master-key K. The springs 19 and 20 and 23 and 24, corresponding to springs 23 and 24 of the other arrangement, are connected in pairs and to the springs 11 and 16 of the ringing-key K. The master-key has a look, as before, consisting of the same kind of a bell-crank controlled by magnet N in circuit with contacts 17 and 18 on the ringing-key. The master-key is locked in position whether up or down as long as the ringing-key is down. The generator G is grounded on one side by the wire 32. With this arrangement suppose ringing current is to bethrown on the metallic circuit it follows this path: G, 31, 25, 23, 4:2, 35, 11, 12, cord-conductor 8, sleeve of plug P, out to line and back by the tip side, tip of plug P, cord - conductor 10, 15, 16, 34, 4:3, 21, 30, and back to generator. Observe that this puts the side 30 of the generator-circuit to the tip side of line. If the master-key be thrown over to the right. and ringing-key depressed, the connection will be reversed and wire 30 will go by way of spring 26, spring 24, wire 35, spring 11, and spring 12 to sleeve of plug, while the return will be to tip 10 15 16 43 20 22 31that is, the generator may be caused to ring in either direction-and if it gives pulsating current its reversal may send positive or negative pulsations to one side of line at will, returning in each. case by the other. One side of the generator is grounded at 32, and consequently as the generator connections are reversed to line this ground is on one side or the other. If, then, there are grounded bells, they may be selected by suitably altering the grounded sidethat is, by turning the masterkey one way or the other. Inasmuch as alternating current is the same either way the direction of ringing for the metallic circuit is ordinarily of no moment and, as before, the grounded bells most used are put on the sleeve side of the lines. Thus the key in its normal position (shown) will permit any metallic circuit-bell or any bell on the sleeve side of line to be rung up without moving the lever. To ring tip side bells, however, the lever is thrown over and when over is locked, of course, until the key K is released.

It may be said that if bells are to ground from both sides of line the metallic-circuit connection would cause both to ring. This is not so, however, as the ringing is usually done through a limiting resistance, such as a bank of incandescent lamps, and it is especially 'not so if the bells are high-wound, as they usually are.

Having thus described our invention, what we claim, and desire to secure by Letters Patent, is

1. In a telephone system, a subscribers line and bells connected to the opposite limbs thereof to be actuated by current over one or the other of the limbs, a ringing-key adapted to make connection with the line, a selective master-key and a generator, the master-key connected and arranged to complete the circuit of said generator in direct or reversed relations with the contacts of the ringing-key, together with means to lock the master-key when set and means actuated by the ringing-key to control said locking means, substantially as described.

2. In a telephone system, a line-circuit, two stations connected to said line and signal-bells thereat, one connected to one side of the line and ground, and the other to the other side of line and ground, a signaling-generator having a grounded terminal, a switch to connect said generator to line, a second switch to connect the generator in direct or reversed relation to the first switch, so as to bring the grounded terminal to one side or the other of line as desired, together with locking means therefor, and a controlling connection from. said locking means to the first switch, whereby the second switch is locked when the first switch is actuated, substantially as described.

4. In a signaling system, a circuit and two or more signal-receiving devices connected thereto, signal-transmltting apparatus comprising a selector, a signal-transmitter and means operated by the transmitter to lock the selector, substantially as described.

5. In a party-line telephone system, a subscribers line connected to two or more subscribers stations, selective receiving apparatus at each station, a central station also connected to the line, and an operators signaling outfit comprising a selective switch, a ringingkey, a suitable source of current-supply, a lock for the selective switch, an electromagnet controlling the lock, and a circuit including said magnet and adapted to be opened and closed in the operation of the ringing-key, substantially as described.

6. In a party-line telephone system, two or more subscribers stations, a metallic circuit passing to all the stations and signal-bells thereat connected from the opposite limbs of the metallic circuit to ground respectively, a central station and terminals for the circuit therein, operators metallic cord circuits adapted to make connection therewith, and selective ringing apparatus for said cord-circuits comprising a metallic-circuit ringingkey having sets of contacts connected to opposite sides of each cord-circuit, a generator having one terminal grounded, a master-key connected to said generator and adapted to 'connect the ungrounded terminal thereof to one side or the other of the ringingkey, whereby the generator may be included between the ground and either side of a cordcircuit, a lock adapted to hold the master-key in either position when actuated, an electromagnet controlling said lock and a circuit for said electromagnet including a source of current-and contacts controlled by the ringingkey, substantially as described.

In witness whereof we have hereunto signed our names in the presence of two subscribing witnesses.

JACOB W. LATTIG. CHARLES LANE GOODRUM.

WVitnesses:

M. S. LEWIS, EDWARD E. CLEMENT.

Images