US276087A - Telegraphic relay - Google Patents

Description

(No Model.) 2 sheetssheet 1.

J. P. SMITHERS.

TELEGRAPHIC RELAY.

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2 S R E H m m S P J TBLEGRAPHIG RELAY.

No. 276,087. Patented Apr. 17,1883.

lllllll "UNITED STATES PATENT Oinrica.v

JOSEPH P. SA'IITHERS, OF BROOKLYN, NEW YORK.

'TELEGRAPHIC RELAY.

SPECIFICATION forming part of Letters Patent No. 276,087, dated April 17', 1883.

Application filed January 17, 1883.

To all whom it may concern:

Be it known that I, JOSEPH P. SMrrHERs, a citizen of Great Britain, residing in Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Telegraphy, of which the following is a specification.

My invention applies to the Morse system of telegraphy, operating on the close-circuit plan, and relates more especially to the relays, and aims to greatly increase their sensitiveness, so that they shall be able to respond to the slightest operating variation in the strength ofthe current, whereby messages may be transmitted over the line notwithstanding the existence of serious grounds or leakages between the sta tions, such as would render the present relays inoperative.

An ordinary Morse telegraph system, arranged on the close-circuit plan, consists, as is well known, of the insulated line-wire extending from one station to the other, and connected at each end in the respective stations to the coil of the relay-magnet, thence with the operating-key, the main battery, and finally to ground. Normally both keys are closed, hence the term closed circuit, and the current therefore continues to flow from one battery through the first relay and key along the line through thedistant relay and key, thence I to the distant battery, and to ground. Hence, if the key in either station be opened, the circuit ot' the line will be broken and both relays will become dernagnetized, thereby correspondingly operating their local sounders in the ordinary way, and thus recording the signal in the receiving-station which has been made in the sending-station. This will always be the action, if we consider the line-wire as a perfectly-insulated conductor, which it is not in fact; but if any serious leakage or groundconnection exists at any point along the line between the two stations, which leakage always exists to more or less extent, the result will then be that the opening of the key at one end of the line will have little ell'ect in demagnetizing the relay or breaking its circuit at the other end of the line, for the current from the distant battery will yet continue to flow "through the distant relay along the line and go to ground through the intermediate leak or leaks, thus keeping the distant relay mag- (No model.)

netized with more orless strength, although the key at the other end of the line is open, and thus leaving the receiving-relay unable to respond to the breaking action of the sendingkey, or able to respond but feebly thereto,

necessitating a very high adjustment of the relay to enable any message to be received at all. It will therefore be seen that in theordinary close-circuit Morse system, here any serious grounds or leaks exist between the two stations, the distant relay will be constantly magnetized bythe current which will continue to flow atthe leak, so that the effect of opening the key at the near station will simply be to reduce the strength of current in the line, and not to actually break the circuit or prevent the tlow at the leak, so that this How will still continue to hold the relay-armature, r

or tend to hold it, after the key is opened. tel-aye therefore require to be very tinely adjusted, so as to respond to \veakenings, and not simply to actual breaks in the current by the action of the distant keys, and if the grounds on the line are strong it sometimes happens that the relay will not respond at all to the opening of the distant key, for the reason that relays as heretofore constructed cannot be made sensitive enough to the slight changes in the current strength which the operator at the distant key causes, where strong grounds exist between the two stations. Now, by my improvement I greatly increase the sensitiveuess of the relay and enable it to respond forcibly to most minute differences of current strength, so that messages can be sent over the line notwithstanding the existence of a ground, which would render the present system inoperative.

The main feature of my invention may therefore be stated to consist in the employment of an auxiliary electric circuit with an auxiliary magnet or electro-motive device in said circuit so arranged as to assist the retracting tendency of the relay-armature when in its at traeted position, and, per contra, to assist the attracting tendency of the relay-armature when in its retracted position.

My invention also embodies a number of special features, as hereinafter fully set forth.

In the drawings, Figure 1 is partly an elevation and partly a diagram illustrating the preferred embodimentot' niyinvention. Figs.

IOU

2, 3, and at illustrate modified forms of my invention.

In Fig. 1, a indicates the relay-magnet; l), the main battery, and c the ground-connection. (1 indicates the line-wire which comes in from the distant station and connects to one end of the relay-coil, the opposite end of which connects to the main battery in the usual manner, as illustrated. The letter E indicates the local sounder, f, the local battery, and g g the local circuit, which circuit passes through the contacts of the relay, as usual, so that the attraction and retraction of the relay-armature, due to the opening or closing ofthe line, correspondingly opens and closes the local circuit and operates the local sounder, as in the ordinary system. In my improvement, however, the relay-armature and its contacts involve new features, and these contacts, together with the local circuit and the local sounders, are made to perform new functions, which renders the action of the relay sensitive to the slightest changes in the line-current,

and enables it to respond to the operation of the distant key, notwithstanding great leakages between the two stations.

Referring now to Fig. 1, It indicates a secondary or auxiliary electro-magnet, which is arranged close to the relay, and preferably in a position directly over the same, withits poles terminatingin about the same plane as the poles of the relay. The coil of this auxiliary. magnet is situated in an auxiliary circuit, '1', which includes the local batteryf and the back or retracting contact on the local sounderthat is, this auxiliary circuit is completed through the armature c of the local sounder, and through the adjustable stop -screw 7;, which limits the retracting motion of the armature. The other stop-screw, Z, which limits the attracting motion of the armature, strikes on a metal pin in an insulating-bushing, m, which is embedded in the arch of the sounder, so that the attracting movement of the armature will emit a clear metallic sound, yet its contact with the arch of the sounder will be non-conducting, so that when the armature is attracted the auxiliary circuit '5 will be open at the retracting stopscrew 7;, as shown in Fig. 1.

Now, nindicates the armature and armaturelever of the relay-magnet, which is of substantially the usual kind, and 0 indicates the retracting-spring thereof, which is adjustable by means of the winding screw or pin 1) in the usual manner, as illustrated.

r indicatesthe armature and armature-lever of the auxiliary magnet h, which projects toward the relay-armature n, so that the tip of both levers project toward and overlap each other, and are each provided with platinum points 8 where they contact with each other, which constitute the relay-contacts, as will be understood. Hence one end of the local circuit g connects to the relay-armature a, and the other end to the auxiliary armature r, so that the local circuit is completed through the two armatures and the contacts 8, as indicated. The auxiliary armature r is provided with the ordinary arrangement of retracting-spring t and adjustable winding-pin t, as indicated. A metal post, a, rises up in front of the armatures, and is fitted at the top with a metal adjusting-screw, a, which limits the retracting motion of the armature 1', while a second adjusting-screw, x, at about the middle of the post, and having an insulating-tip, limits the retracting motion of the relay-armature. A third stop-screw, w, behind the armatures, limits the attracting motion of the two armatures. A shunt, y, of low resistance is formed in the main line d, around the relay-magnet a, one branch of which shunt connects to the auxiliary armature 9', while the other branch connects to the metal post a, this shunt being normally open at the stop-screw c, as shown.

The general organization having been new described and illustrated, it will therefore be understood that when the apparatus is quiescent the parts will be in the positions indicated in Fig. 1-that is, while the circuit of the line (I is closed the shunt y will be open at v, and the relay a will be of course energized, and its armature it attracted against the armature r, and hence the contacts 8 will be closed, and the local circuit 9 accordingly closed, and the mag net of the sounder E will be energized, its armature 0 depressed, and the auxiliary circuit 1' opened at the point 7.. Hence the auxiliary magnet h will be demagnetized, and its armature r will be controlled by the attracting-pressurc of the relay-armature a, tending to force it toward the magnet, while the retractingspring t tends to pull it, as well as the relayarmature 12, away from the respective magnets. The springs t 0, however, should be so adjusted as to nearly balance the attraction of the relay 0. when the relay-armature is close to the poles. It will therefore be seen that while both springs are so adjusted as to nearly balance the full attraction or" the relay-magnet, yet the two armatures have no tendency to hover on each other, but are pressed togetherwith a full force represented by the attractive force of the relay opposed by the retractiveforce of the spring 2, so that the contacts 8 are hence held closed with afirm pressure, although the armatures are just balanced in front of the relay, whereas if the pressure on the contacts were to be relaxed by this balanced condition the current in the local circuit would become weakened, so as to prematurely affect the local sounder, but which cannot occur in this arrangement. It will be understood, however, that as soon as the line-current and the attraction of the relay weakens appreciably, so as to allow the armatures to retire far enough to bring the auxiliary armature 0 against the stopscrew r, the shunt y y in the line around the relay will then be closed, and hence the line-current will now take that path and cause the attraction of the relay to cease almost IIO Lil

entirely, at which instant the spring 0 will retract the relay-armature it against its stopscrew 00, thus separating the two armatures at the contacts 8, and thereby opening the local circuit 9. The magnet of the local sounder IE will of course at this instant become demagnetized and its armature will retract against the stop-screw k, thereby closing the auxiliary circuit i and energizing the auxiliary magnet h, which will immediatelyattractits armature r, so as to withdraw it against the stress of its spring tfrom contact with the stop-screw o and bring it up against thestop-screw to. This attraction of the auxiliary armature r will, of course, break the shanty and restore the circuit of the line to its normal path through the relay, so that as soon as the current is again strengthened to its normal rate in the line by the closing of the distant key the relay will attract its armature a against the stress of its spring 0 and bring the armature into contact with the attracted armature r of the auxiliary magnet. The spring 0 should be of suiticient strength, and should be so adjusted as to hold the armature a upon its stop or against the attraction of the relay-magnet, due to the ground or leakage current in the line after the shunt g has been opened, as described, and this adjusting of the spring 0 should be suchthat but a slight increase in the strength of the relay will suflice to attract its armature a, as described, for the reason that all the resistance of the auxiliary armature r and its spring t has been already removed from the path of the relay-armature by the previous attraction of the former against the stop to. As soon, however, as the relay-armature is fully attracted by the relay-magnet and brought close to the poles thereof and in contact with the armature r, the

local circuit becomes again closed at the contacts s, and the armature ot' the local sounder is thence depressed, thereby breakingthe auxiliary circuit and demagnetizing the auxiliary magnet h, which thus releases its hold on the auxiliary armature 1'. The relay (t will, however, now continue to hold the two armatures against the stop to, or almost in a balanced condition on the stop, as bel'ore described, for the reason that the springs are adjusted so that they nearly balance the normal attraction of the relay, and because the attraction of the relay as the poles are approached increases, according to a well known principle, in a ratio more rapid than the resistance of the spring tincreases as it is extended, so that when the relay-armature hasbeen once brought up close to the poles it will resist the retracting-pressure ot' the spring t until the attraction of the relay has again weakened suftlcently by the opening of the distant key, when the same chain ot'operations will be repeated.

Hence by this invention it will be seen that when the relay weakens and it armature retreats the resistance to the subsequent attraction of the armature is automatically removed, and, per contra, when the magnet strengthens and attracts its armature this resistance is automatically restored to imparta retracting tendency to the armature, so that a slight weakeningot' the relay will be sufficient to cause the armature to retract forcibly. This action is therefore equivalent to greatly weakening the relay when the distant key is opened, and greatly strengthening it when the distant key is closed. Hence by this system the relay becomes firmly responsive to slight changes in the strength of line-current and of relay attraction, due to opening and closing of the distant key where serious leaks exist between the stations, and at the same time agood contact is maintained at the relay-armature, so that the operation of the local sounder is certain and energetic, thereby effecting a most important improvement in telegraphy. The sensitiveness of this instrument to small changes in the current is such that in an ex perimental circuit in which the key was placed in a shunt or branch I have obtained strong signals when the strengths of current, when the key was closed and when open, were respectively and -5; of an ampere. The difference between these two strengths, or the working-current, was therefore of an ampere.

The apparatus can be made more or less sensitive or responsive to greater or less changes in the line-current according to the adjustment of the springs t 0, as will be understood, and, with a very line adjustment, the instrument will record messages with but an infinitesimal increase and decrease of line-current.

In Fig. 1 it will be noted that the auxiliary circuit 17 and local circuit 9 are distinct, but both supplied by the same local battery, f. A separate battery may, however, be employed for the auxiliary circuit, it" required; but it is not, of course, desirable. are supplied bythe same battery, asillustrated, I prefer to make the coil of the auxiliary magnet h of much higher resistance than the coil of the sounder E, so that as soon as the local circuit is closed at the contacts 8 the current will be at once diverted into the local circuit, causing the sounder to at once attract its armature and break the auxiliary circuit, where as if the resistance of the circuits were reversed or were equal the battery)" would not be oi sufficient force to divide its current between the two circuits and energize the sounder magnet suiiiciently so as to cause it to act the instant that the contacts 8 were closed, which objection is obviated by having the magnet h of much higher resistance than the soundermagnet.

In Fig.2is shownamoditicationof Fig. 1, the corresponding parts being lettered similarly. In this case the auxiliary magnet h is arranged directly in the local circuit; but it acts on the auxiliary armature 1' reversely to that shown in Fig. 1-that is, the auxiliary magnet acts to pull the two armatures out against the shunt eontact a, while the spring t tends to \Vhere both circuitspull the auxiliary armature in the opposite way. The operation and result, however, will be substantially the same as in Fig. l, but not so advantageous, as the adjustments cannot be made so nicely as in the case of Fig. 1.

In Fig. 3 is shown another mode of carrying out the principle of my invention. In this instance the local sounder E serves directly as the auxiliary magnet and acts to strengthen and weaken the retracting-spring 0 of the relay-armature nthat is, the relay-spring 0 is strengthened when the relay-armature is attracted, and is weakened when the relay-armature is retracted. It will be noted that the relay-magnet a and the magnet of the sounder E are so arranged that they attract their armatures a e in opposite directions, and that the retracting-spring 0 of the relay-armature connects directly to the armature of the son nder. By this arrangement it will be seen that when the key of the line (1 is open the armature n will be retracted, the contacts 8 will be separated, and hence the local circuitg will be broken and the sounder E demagnetized, with its armature e retracted, as indicated by dotted lines, thereby relaxing the retracting-spring 0. The spring being thus automatically weakened, a slight increase in the attraction of the relay a will therefore suffice to attract the armature n, which, being then brought up close .to the poles of the relay, will be held there firmly, and thus close the local circuit at the contacts 8, thereby causing the sounder to again attract its armature, and thereby distend or strengthen the spring 0, thus imparting an increased retracting tendency to the relay-armature, which tendency will become efit'ective to retract the armature as soon as the attraction of the relay weakens appreciably, thus rendering the relay much more sensitive to the opening and closing of the distant key.

This arrangement has, however, the objection of weakening the pressure at the contacts .9; but where a very fine adjustment is not required this instrument will be quite effective and a material improvement over the ordinary relay.

In Fig. 4 another modification is represent ed, in which the local sounder also serves as the auxiliary magnet and acts reversely to that in Fig. 3-that is, instead of acting to strengthen and weaken the retracting-spring of the relayarmature, itacts to strengthen and weaken the attractive force of the relay-magnet, but with thesameefiectasintheformercases. Inthisinstance the coil of the relay is wound in a series of sections or loops, which connect with a corresponding series of pins or seats, 8, on which a switch, 7, turns. The switch is connected by a shunt-branch, y, through the armature and arch of the sounder, with the main battery I), as shown, so as to form a shunt in the line around a portion of the relay-coils. By turning the switch onto one or other of the pins 8 more or less of the relay-coils will-be thrown into connection with the shunt g. It

will hence follow from this arrangement that when the-key of the line at is closed the armature a will be attracted, the local circuit g closed, the armature of the sounder E attracted, and the shunt y closed, thus causing the line-current to flow through only a portion of the coils of the relay, and hence rendering the attraction of the relay on its armature comparatively weak. As the armature, however, is now attracted close to the poles, the weakened attraction of the relay will still somewhat overbalance the springo when properly adjusted; but a slight additional weakening of the magnet by the opening of the distant key will cause the spring 0 to preponderate, and thus retract the armature, which will thereby break the local circuit. The armature of the sounder E will then retreat and break the shunt y, thus throwing all the coils of the relay into direct circuit with the line, so that when the distant key is again closed the increased line-current will flow through all the coils of the relay, and thus increase its attraction and cause it to greatly overbalance the spring 0. The relay-armature will thence be strongly attracted, and will therefore again close the local circuit g, thereby causing the local sounder to again close the shunt y, and thus again reduce the strength of the relay, so as to leave the armature of the relay on the hovering point, ready to retract at a slight reduction in the line-current, as before described. This modification is, however, liable to the same objection as in Fig. 3that of weakening the local circuit by relaxation of pressure at the contacts 8.

In Fig. at an insulator, m, is introduced in the tip of the sounding-armature c to render the contact with the retracting stop-screw 7c non-conducting, so as to prevent the shunt 11 from being closed at that point, as will be understood. I The arrangement shown in Fig. 4 may be modified as follows: Instead of using the sectionally-wound relay and the adjustable switch 7, the switch may be dispensed with and an ordinary wound relay substituted, and the shunt 3 may be connected with the line (I, as indicated by dotted lines, through an adjustable resistance equal, say, to half that of the relay, or any other proportion desired. Hence when the shunt y is closed at the sounder, as before described, the line-current will be (livided between the relay and the adjustable resistance, thus weakening the relay after its armature has been attracted, as before described. On the other hand, when the shunt is opened by the retraction at thesouuder the line-current will pass entirely through the relay, thus proportionately strengthening it atter its armature has been retracted, thus giving the same effect as the first-described arrangeinent.

In Fig. 2 is shown an additional feature not heretofore described, and which may be also applied to the instrument shown in Fig. 1-that IIO is. the armature of the relay may be provided with a small electro-magnet, a, with its poles opposing the. poles of the relay a. The coil of this armature-magnet will be in circuit with the shunty,which is normally open at the point a, and hence while so open the relay-magnet will attract the core of the electro-magnet in the same manner and with the same ettect as the ordinary simple armature. As soon, however, as the two armatnres r a retract sufficiently to bring the armature 1' against the stop o,the shunt y will be closed and the electro-magnet a will be energized, and will thus repel the armature-lever a from the poles of the relay in aquick and energetic manner, thus suddenly and greatly increasing the retractile power of the armature at the instant that the line-current on the relay begins to appreciably weaken by the opening of the dis taut key. Instead of using an electro-magnet, a, to obtain the repelling effect, a permanent magnet may be substituted with a small battery, y, in the shunty, arranged to send a reverse current through the relaycoils rid the loop (I 3 17 r.

Fig. l embodies the most perfect and advantageous form of myinvention, and this may be used either with or without the electromagnet armature 02, (shown in Fig. 2,) as will be understood. The arrangement shown in Figs. 1 and 2 may also be used without the cut-out shunt 9 but this feature is quite desirable, as it renders the retraction of the armature much quicker and more energetic.

It will be readily seen that the several moditications of my invention shown in Figs. 2, 3, and 4 all involve the same principle of employing an electric circuit with an electro-motive device controlled by the movements or contacts of the relay-armature to assist the action of the relay, so as to automatically strengthen the retractile tendency of the armature after the armature is attractethand to automatically Weaken the retractile tendency when the armature is retracted. I do not therefore confine myself to any of the specific forms of apparatus herein illustrated, and any other specific form of apparatus involving the same principle may be employed without departing from the essence of my invention.

It will he observed that the great and characteristic advantage of my invention is the practicability of working telegraph-lines with minute differences of strength in astrong current, and not only will the relays thus work over great leaks and the sounders respond energetically, but the receiving instrument will respond much more quickly to the sendingkeys than with the present system, for after closing and opening the key it alwaysrequires, of course, some appreciable tim e for the current to rise in the distant relay to the point at which it attracts its armature, or to fall to the point at which the armature retracts; and as my improvement requires a much smaller change of current to operate the armature, it follows that the action of the relay will be much quicker.

It will be also noted that by my system an energetic retracting impulse is imparted to the relay-armature at the instant that its attraction weakens perceptibly, so that hence the lagging efieet of residual magnetism will by this means be efi'ectually overcome, and the armature thrown out forcibly at each retraction. This will enable the armature to be worked in very close proximity to the poles without sticking by residual magnetism; and hence a weaker battery will have the same effect as a stronger one would have on the ordinary relay. This advantage will be of importance where the invention is used on lines arranged on the opcncircuit system, for while the apparatus is more especially designed for the closed-circuit system, it willalso be applicable to the open-circuit system, as will be understood.

It will be readily understood that while an electro-magnet, h, is the most desirable form of electro-motive device to employ in the auxiliary circuit for the purpose described, yet any other equivalent electro-motive device which will serve the same purpose may be adopted; but it is not thought that any other form of electro-motive device other than an electro-magnet will be found suitable.

It will also be understood that any equiva lent for the retracting-springs if 0 may be substituted.

\Vhat I claim is 1. The combination, with a receiving telegraphic magnet or relay, of an auxiliary electric circuit controlled by the contacts or move ments of the armature of said magnet, with an electro-motive device in said circuit arranged to assist the action of the relay, substantially as herein set forth, whereby the tendency of the armature to retract is increased after it has been attracted, and is decreased after it has been retracted, substantially as herein specified.

2. The combination, with a relay-magnet and its armature, of an assisting-magnet and its armature, arranged to assist the movements of the relay-armature, substantially as herein specified, said armatures beingarranged to contact with each other, and witha local or sounder circuit passing through said contacts, arranged and operatingsubstantially as herein shown and described.

3. The combination, with a telegraphic magnet or relay and its armature, ot'an assisting or auxiliary magnet and its armature arranged to contact with the relay-armature, and with retractingsprings opposing the respective magnets, with a local or sounder circuit passing through the contact of said armatures, and an auxiliary circuit in which said auxiliary magnet is located, arranged to pass through contacts operated by the sounder, the whole being so arranged that the retraction of the relay-armature will break contact with the auxiliary armature, and thereby break the local circuit, which in turn will cause the armature of the local sounder to retract and close the auxiliary circuit and cause the auxiliary magnet to attract its armature, Whereas the attraction of the relay-armature will close contact with the auxiliary armature and produce the reverse action of the aforesaid parts, substantially as and for the purpose set forth.

a. In a telegraph system, the combination, with a relay-magnet and its armature, and with means, substantially such as set forth, to assist the action of the armature, of a cutout shunt, y, in the telegraph-line around the relay,which is closed when the relay-armature is partly retracted, and opened When the armature is fully retracted, substantially as and ;for the purpose set forth.

5. In a telegraph system, the combination, with the auxiliary magnet h and its armature 1', of the relay-magnet a and its armature n, and the retracting-springs t o, with the local circuit g, the retracting-stops o w, and an auxiliary circuit in which the auxiliary magnet is located, with the local magnet or sound er E, controlling said circuit, arranged and operating substantially as and for the purpose herein shown and described.

JOSEPH 1. SMITH ERS Witnesses CHAS. M. HIGGINS, J NO. I GAVIN.

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