US1183292A - Selective signaling system. - Google Patents

Description

E. R. GILL.

SELECTIVE SIGNALING SYSTEM.

APPLICATION FILED 05c.20.19:0.

1,183,292. Patented May16, 1916.

4 SHEET$SHEET I.

F15- 2- I M 3 E. RLGILL.

.SELECTIVE SIGNAUNG SYSTEM.

APPLICATION FILED DEC. 20, 1910.

1,183,292. Patented May 16, 1916.

4 SHEETSSHEET 2- E. R. GILL. SELECTIVE SIGNALING SYSTEM.

APPLICATION FILED DEC.20, I9I0.

am 1 9 1 n0 1 y m N in u t R an TL a P 4 SHEETS-SHEET 3- m n I I II I I 2 8 2 R. H N m BY l WITNESSES:

snrrnn s'ra'rns rp GILL, OF YONKERG, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, TO HALL SWITCH & SIGNAL COMPANY, A CORPORATION OF MAINE.

EDWIN R.

SELECTIVE SIGNALING SYSTEM.

To all whom it may concern:

Be it known that I, EDWIN R. GILL, re-

' siding at Yonkers, in the county of Testsemaphore,

. bac

chester and State of New York, have invented certain new and useful Improvements in Selective Signaling Systems, of which the following is a specification.

This invention relates to improved means for controlling semaphores and similar signals from a distance.

An object of the invention is to provide aplurality of semaphores, or the like, along a railroad track,the action of any one of which may be selectively and exclusively determined by means under the control of a despatcher through'a telephone line, or the like, along the track.

Another object of the invention is to provide, in connection with a system such as that last referred to, answer back means whose operation is determined by that of the for automatically causing the the main line of answer whereby the dethe operation of im ression upon signaling impulses, spatcher 1s apprised of the particular semaphore with which said answer back'means is identified.

Another object is to provide, in a system of the kind described, means whereby the despatcher may place any one of a, number of' semaphores normally biased to one position, in such condition that it may be manipulated to assume another position, and whereby an answer back signal will be returned to the despatcher, to inform him that the semaphore is in condition for such manipulation, and that, furthermore, a lo cal signal has been given at the semaphore, to call the attention of the semaphore attendant.

I also aim to combine, in a system of the kind described, means whereby the despatcher may set any one of a number of semaphores in condition so that it may be.

brought from its normally maintained position to another position; means whereby when the semaphore has been so set by the despatcher, a signal will be given at the semaphore, to call the attention of the semaphore attendant, the operation of said signal impressing upon the line signaling impulses which will indicate to .the despatcher that Specification of Letters Patent.

-therefore, that the semaphore is ready for broad invention, and to the details of con- T.

'phores along the line; and Fig. 8 is a trans Patented" May is, rare.

the signal at the semaphore is operating, and

manipulation; means whereby, when the semaphore attendant has manipulated the semaphore to the extent allowed by the control which the despatcher has exercised, answer back signaling impulses will be impressed upon the line, codified to identify the particular semaphore, thereby to apprise the desp'atcher'that it has been ma- 1 nipulated and its position changed.

Another object is to combine in a system of I. the kind described, means as previously set forth, vincluding an electro-magnetie semaphore control, whose operation is governed by a polarized relay, automatic means for impressing codified series of impulses upon the line, and means for changing the polarity of such series of impulses.

Other objects and aims relating to the Y struction and arrangement ancillary thereto, will be in part obvious and in part pointed out in the following description; and the scope of protection contemplated will be defined in the'appended claims. In the accompanying drawings, which are to be taken as a part of this Specification, and in which ,I have illustrated a merely preferred form of embodiment; Figure 1 is I an elevation of a semaphore device including my invention; Fig. 2 is a similar view at right angles,-partly broken away; Fig. 3 is a view of the semaphore controlling mechanism proper, with the parts positioned as in one operative condition; Fig. i is a view similar to Fig. '3, of the parts as in another ,1, operative condition; Fig. 5 is a View similar to Fig. 4, partly broken away, of the parts l as in another operative condition; Fig. 6 is a view of the subject-matter of Fig. 3, taken kat right angles thereto and with the back of the casing removed; Fig. 7 is a diagrammatic' showing illustrating the operative parts at and connections between a dcspatchers oflice and a plurality of semaverse detailed sectional view, said'section being taken substantially on the plane of line 88 of Fig. 6, for illustrating the manner of preventing rotation of certain parts of the semaphore controlling mechanism.

I will first describe the semaphore controlling mechanism proper, that s to say, the parts which are connected directly to the semaphore arm, reference being had to Figs. 1 to 6 inclusive, in this connectlon. The numeral 1' accordingly indicates a pillar or support, at the upper end of which is pivoted in the ordinary way a semaphore arm 2, so balanced that it is biased to assume the horizontal position of Fig. 1, which is the danger position, and an operating rod 3 is connected to the semaphore arm to one side of its pivot in such a manner that movement of the rod swings the arm on its pivot. The rod 3 extends down into a box 4 which is carried on the support 1, where it engages a sleeve 5 that is slidable within the box and whose lower end is connected to a link 6, which causes reciprocatory motion of the sleeve 5, brought about by manipulation of the hand lever 7, which is pivoted to the support 1 as shown. The telescoping members 3 and 5 are kept in alinement by their engagement with each other, and by means of suitable guides where they enter box at at top and bottom, respectively, being held against rotation by a guide 13 fixed within the box, in a plane par allel to the longitudinal axis of the telescoping members, and adapted to be engaged by a guideway formed on the collar 8 carried by the sleeve 5. The collar 8 is preferably arranged adjacent the upper end of the sleeve 5 and carries a pivoted meme vber 9, having a tooth 10 adjacent its pivot,

and carrying at its lower end an anti-friction wheel 11. This tooth 10 is adapted to enter a slot 12 in the sleeve 5, that registers with a recess 14: in the rod 8, when the rod and sleeve are in the relative positions shown in Fig. 5. The tooth 10 passing through the slot and into the recess will obviously lock the rod and sleeve together so long as it remains in the position of Fig. 5. If there were nothing to prevent the swinging of the member 9 upon its pivot, it is obvious that the tooth 10 would not maintain the engagement between the rod and sleeve. 1 provide, however, means for preventing, at will, such pivotal movement, said means preferably taking the form of an arm 15 that is pivoted in the lower part of the box, extends upwardly in line with the member 9 throughout the phase of bodily movement of the latter, and carries at its free end an armaturettl, which constitutes the keeper for a magnet 17 mounted in the upper part of the box and adapted to be energized and denergized by means herein after to be described. The position of the arm 15 when the magnet is de'e'nergized is shown in Fig. 3, and its position when the magnet is energized is shown in Fig. 4. A leaf spring 18 engages the arm 15, and

.of the magnet 17,

meaaea urges it in the direction of the magnet 17. riupposing the magnet 17 to be deenergized, it the lever 7 is lifted up, the sleeve 5 will a move downwardly, the tooth 10 riding over the surface of the rod 3 until the slot 12 and recess 14 come into registry. Though the tooth swings into the recess, rod and sleeve are not locked together, because upward movement of the sleeve, in connection with the downward tendency of the rod, will at once throw the tooth out of the recess. If, however-,the magnet is energized, and the armature 16 attracted to it, when the tooth 10 is brought to position to enter the recess 14, thearm 15, by the force of spring 18 and. the attraction of the magnet will hold the tooth'in the recess, as shown in Fig. If now the lever 7 is pulled down, thereby sliding the sleeve 5 upwardly, the tooth 10 will be held in its engagement with the recess 14 throughout any upward movement :ot'the sleeve, because the arm 15, while the 'magnet 17 is energized, will be held nearer to the sleeve and rod than when the magnet isnot energized, and in the movement of the sleeve and rod the wheel 11 will simply ride on the surface of arm 15 without permitting any appreciable pivotal movement of arm 9. Consequently, on moving the lever 7 downwardly, the sleeve 5 will be moved upwardly, carrying the rod 3 with it, thereby moving the se'maphorearm to the position indicated in dotted lines in Fig. 1, where it may be heldby securing the lever in position by means of a pivoted lock 25. Oh- .viously, if it be desired to return the semaphore to danger, it is not necessary again to move the lever, but upondenergization the bias of the semaphore arm will tend to throw the tooth 10 out of the 'recess 14, the arm 15 yielding to the pressure of wheel 11, so that the lock between the rod and sleeve is broken and the semaphore returns to danger by its own gravity. 7

By the mechanism thus far'described it is obvious that if the magnet 17 is deenergized, any movement of the lever 7, whether up or down,. will have no effect upon the semaphore, because the rod 3 and sleeve 5 will not be locked together and consequently the movement of the sleeve due to its connection with the lever will not affect the rod 3. But, if the magnet is energized, the rod and sleeve will be locked together and upward movement of the sleeve will result in throwing the semaphore to clear. Obviously, also, if the semaphore is at clear, and held in that position by the locking of lever 7, the semaphore may be returned to danger without manipulation of handle 7, by simply deenergizing the magnet 17, whereupon the bias of the semaphore will break the lock between the rod and sleeve and slide the rod down i 35, with the winding lever of a sending key 1, 183,292 til within the sleeve. The energization of the magnet and consequent locking of the sleeve and rod, and the movement of the rod thereafter to throw the semaphore to clear are utilized to actuate an answer back signaling device, as follows: A sleeve 26 surrounds the sleeve 5 as shown in Fig. 5, for instance, and is capable of a limited relative longitudinal movement, a pin 27 being threaded through the wall of the box and entering a longitudinal slot 28 in the sleeve 26, so that the sleeve 26 may move longitudinally the length of said slot. A. spring 29 is attached to the upper end of the sleeve 26, whence it extends to the upper end of the box, where it is secured by an adjustable connection 30, said spring tending to draw-the sleeve 26 upwardly. There is a. flattened pin 31 at the lower end of rod 3, extending laterally there-- from, and slidable within a slot 32 in the sleeve 5, and an alined slot 34 is cut in the upper end of sleeve 26. The pivoted member 25 is formed at its upper end, above the U-shaped member 20 that embraces sleeve 26, with an opening 33, which when the parts are in the position of Fig.3, takes over the pin 31 under the influence of spring 24. The sleeve 26 is connected, as by means of a link 36, such as is shown for instance in my copending application Serial No. 563,395, so that upon longitudinal movement of the sleeve 26, the sender 36 will be either wound up,lor released for its sending function, according to the direction of movement of sleeve 26.

Considering now Fig. 3, the parts are all in normal position, the semaphore at danger, and the magnet 17 denergized. Any movement of the lever 7 which will bring the sleeve 5 down to the position shown in Fig. 5, will not result in looking the sleeve 5 and rod 3 together. The member 25 may be swung on its pivot 22 by wheel 11 to remove the hook 33 from engagement with the pin 31, but without result. The weight of the rod 3 on the pin 31, engaging the bottom wall of slot 34, holds the sleeve 26 down, against the tension of spring 29 and so prevents operation of the sender 36. Also, up-

ward movement of the sleeve 5 will have no effect uponthe rod 3, because the. bias of the semaphore, in the absence of energization of magnet 17 prevents locking together of the rod 3 and sleeve 5 by the tooth 10. If, however, the parts are in the position of Fig. 3, and the magnet 17 is energized, and the sleeve 5 is drawn down by manipulation of lever 7, then the wheel 11, in its downward travel, is forced against the member 20 and swings the member 25 to the position of Fig. 5, releasing the pin 31 from the hook 33, and holding the tooth l0 positively within the recess 14 of the rod 3, whereby said rod and the sleeve 5 are locked together. If 6 now, upon manipulation of lever 7, the sleeve 5 is moved upwardly, it will carry with it the rod 3, to the position shown in Fig. 4, which corresponds to the clear position of the semaphore, and in this position 7 if 28, under the influence of spring 29, and this 7 movement of sleeve 26, as before explained, sets into operation the sender 36, which, as hereinafter set forth, sends a. signal over the line apprising the despat'cher of the fact that the particular semaphore has been thrown to clear. If the semaphore attendant does not lock the lever 7, the bias of the semaphore will return the parts to the position shown in'Fig. 5, the semaphore returning to danger. Consequently the semaphore attendant can throw the apparatus to danger when it is at clear, but he cannot throw it to clear when it is at danger, without energization of magnet 17, which, as hereafter explained, is solely in the control of the despatcher. He may move it in either direction so long as the magnet 17 is energized but has no control over it when the magnet is denergized. The semaphore cannot stand at clear except while the magnet 17 is energized. The despatcher, in the embodiment shown, does not energize the mag net 17 to throw the apparatus from danger to clear, but supposingit is at danger, he

net 17, whereupon the bias of the semaphore returns it to danger, as described.

The magnet 17, in Fig. 7, is the semaphore magnet, and the make and break wheel 37 in Fig. 7 is a part of the sender 36, and I will now describe the manner in which these are afiected by certain instrumentalities shown in the said Fig. 7. I

Referring to Fig. 7, 38 and 39 indicate the sides of a line, in a bridge of which is a telephone receiver 40, said bridge inc uding a condenser 41, as usual. There is also a bridge 42 including a condenser 43. 44 indicatesa main line battery, from which,

by means of a pole changer 45 havingconto make contact with the contacts 46 and 47, respectively, of the pole changer 45. The winding of the relay 50 is included in a local circuit 51 which includes a local battery 52,

and a plurality of sender keys 53, preferably.

such as are shown and described in my copending application Serial No. 563,395..

Between the armature 48 and 49 and the line, I preferably provide resistances 54 and 55, and also a bridge including a condenser 56. The several keys 53 are arranged to produce in the circuit 51 different series of impulses, and such impulses will result in impressing upon the line from battery 44 through pole changer 45 and armatures 48 and 49, similarimpulses, though the po-- preferably such as is shown in my Patent.

No. 906,523, and comprising a toothed member adapted to be stepped up by codally arranged impulses as transmitted through the magnet 56 under the control of a key 53. As shown in the diagram, the course of a current from battery 44 would be from contact 47 to armature 49, wire 58, wire 59, resistance 55, wire 60, wire 61, wire 62, wire 63, re istance 64, wire 65, wire 66, resistance 67, wire-68, wire 69, coil 70, wire 71, magnet 56, wire 72, wire 73, resistance 74, wire 75, wire 76,resistance 77, wires 78, 79, 80, and 81, resistance 54, wire 82, wire 83, armature 48, contact 46. When, upon a proper series of impulses, taking the course described, the toothed member has been stepped up until a contact member 84 carried thereby makes a contact at 85, the circuit is as follows: contact 47, armature 49, Wire 58, Wire 59, resistance 55, wire 60, wires 61, 62, 63, resistance 64, wire 65, wire 66, resistance 67, wire 68, wire 86, through one coil 87 of a polarized relay 88, wire 89, contact member 84, contact 85, through hell 90, to the other coil 91 of relay 88, wire 92, wire 73, resistance 74, wire 75, wire 76, resistance 77, wires 78, 79, 80, 81, resistance 54, wire 82, wire 83, armature 48, contact 46 to battery 44. The passage of current through the coils of relay 88, energizes one or the other of thesemagnets, in accordance with the polarity of the current, to actuate pivoted armature'93, which, in one position, as shown in the diagram, closes the local circuit 94 which includes the semaphore magnet 17 said local circuit including alocal battery 95. Supposing the parts to be in the respective positions indicated in the diagram, which, since magnet 17 is energized, means that the rod 3 and sleeve 5 of the semaphore mechanism are locked together, if the semaphore is now actuated to throw it to clear bythe semaphore attendant, this movement will cause the rotation of the make-and-break wheel 37 which opcrates, through a movable contact 96, to open and close alocal circuit 97 including a local battery 98, said movable contact 96, and a coil 99 that is in inductive relation to coil 70. Consequently the impulses impressed upon the local circuit 97 through the wheat 37 will produce corresponding induced impulses upon a circuit of which the coil 70 is a part, and whose course may be traced as follows: coil 70, wire 71, magnet 56', wire 72, wire 73, resistance 74, wire 75, wire 76, resistance 77, wires 78, 79, to the telephone bridge, thence to wire 62, 63, resistance 64, wires 65, and 66, resistance 67 wire 68 and 69. The effect of theimpulses thus set up will be to cause an audible signal in the receiver. 40, which signal is appropriated to and identifies the particular semaphore which has been thrown to clear. The function of the bell 90 is simply to call the attention of the semaphore-attendant, and actuation of this bell, of course, takes place before the semaphore is moved to clear, and therefore prior to the actuation of wheel 37. The interruptions in the line caused by the operation of the bell willset up impulses in the telephone bridge and cause an audible signal in the receiver 40, whereby the de-' spatcher may know that he has successfully called the station to which the bell is appropriated and that the semaphore mechanism at that station is in condition where it may be thrown to clear by the attendant.

If it be desired to release the locking engagement between the rod '3 and sleeve 5 of the semaphore mechanism, and therefore to make it impossible to hold the semaphore at clear, the despatcher reverses the pole changer 45, and operates the same key 53, again thereby actuating the same selector 57 and closing circuit through the relay88, which, because of the reversed polarity of the current, will operate the armature 93 to open the local circuit 94, whereby the magnet, 17 is deenergized, and the lock between the rod 3, and sleeve 5 of the semaphore mechanism is broken, so that the semaphore cannot be thrown to clear. -Upon this operation the bell 90 again operates to inform the despatcher by the induced signal set up in the receiver 40, that he has broken the semaphore magnet circuit and that the semaphore stands at danger.

I have described the control of the apparatus at one station,

but it will be understood that there may be as many stations along the same line as desired, all of which will-be within the control of a single pole changer and double acting relay, in connection with the appropriate sender keys 53. At each station there will be a selector in bridge of the line, which is actuated to close the bridge of the relay which determines the movements of the circuit breaker for the semaphore magnet circuit; parts of said bridges being preferably coincident. Also at each station there will be the answer back mechanism and the local circuit afi'ected thereby to cause the impression of induced currents on the line.

While I have shown and described certain preferred mechanism and certain preferred electric circuits and appliances and arrangements thereof, it is to be understood that the scope of my invention is not limited by any specific description, but only by the requirements of the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is: i

1. In a system of the kind described, the combination of a plurality of signal members each adapted to be manually moved to two positions, selectively operated means for electrically controlling the movements of said members, the possibility for the movement of each member being dependent upon the operation of the corresponding selector and a signal for each member, the operation of which is determined by that of said member.

2. In a system of the kind described, the combination of a line, a signal member adapted to be manually moved to two positions, electro-mechanical means for deter mining the possibility for the movement of said member in any direction, selective means, includin a polarized relay arranged for controlling t e operation of said electromechanical means and means for impressing upon the line a complete call consisting of a succession of codal impulses of either polarity to actuate said selective means.

3. In a system of the kind described, the combination of a line, a selector on said line, a signal member adapted'to be manually moved into two positions, the possibility for movement thereof being dependent upon the operation of said selector, means for impressing impulses upon the line to control the movement of said selector, answer-back receiving means in the line and means operated by the movement of the signal mem-. ber adapted to impress answer-back impulses on said line.

4. In a system of the kind described, thecombination of a line, a selector on said line, a signal member adapted to be manually moved into two positions, the posslb hty for In asystem of the kind described, the

combination of a signal member adapted to bermoved to two positions, aline, a source of current supply for the line, means for impressing current of difl'erent polarities upon the line, electro-mechanical means for movin saidimember to one position and contro ling the possibility of its manual movement, a signal, the o eration of which is determined by that 0 said electro-mechanical means, and means controlled by the movement of said member for impressing u on the line induced currents.

6. n a system of the kind described, the combination of a member adapted to be moved to two positions, a line, a source of current supply for the line, means for impressing upon the line current of different polarities, electro-mechanical means for moving said member to one position and controlling the possibility of its manual movement, a signal, the operation of which is determined by that of said electro-mechanical means, means controlled by the movement of said member for impressing whereby the position of said members is controlled by the polarity of current in the line,

a plurality of signals corresponding respectively to, and the operation of which is determined by that of the selectors, and a plurality of signals corresponding respectively to, and the operation of which 1s determined by that of said movable members.

8. In a system of the kind described, th

combination of a line, a member adaptedto be moved to two positions, means for controlling the movement of said member, selective means connected to the line for controlling said las't-named means, a signal the operation of which depends upon the operation of the selective means, a movable element the operation of which depends nections whereby said movable element may impress induced currents upon the line. l

9.-'In a system of the kind described, the combination of a plurality of members each adapted to be moved to two positions, a line,

source of current supply for the line,

means for lmpressing upon the line current of different polarities, a plurality of electromechanical means respectively corresponding to and adapted to move said members to one'position, a signal for each member the operation of which is determined by that of the corresponding electro-mechanical means, and means controlled by the movement of each member for impressing upon the line induced currents.

10. In a system of the kind described, the combination of a plurality of members each adapted to be moved to two positions, a line, a source of' current supply for the line, means for impressing current of different polarities upon'the line, a plurality of electro mechanical means corresponding respectively to and adapted to move said members to one position, a signal for each elec tro-mechanical "means, the operation of which is determined by that of said electromechanical means, a plurality of means respectively controlled by the movement of said members for impressing upon the line induced currents, and answer-back receiving means connected to the line.

11. In a system of the kind described,th e combination'of a line, a plurality of members each adapted to be moved to two posi- ,tions,'a plurality of means respectively corresponding to and adaptedto control the movements of said members, selective means connected to the line for -controlling said last-named means, a plurality of signals corresponding to said'members the operation of which, depends upon the operation of the selective means, a'plurality of movable elements corresponding to and the operation of which depends on that-of the movable :members, and connections whereby said movable elements may impress induced currents upon the l1ne.,

12. In a system of the kind described, the v combination of a line, a selector connected to, the lineand adapted to be actuated by current impulses therein, a member adapted" to be moved to two positions, the possibility for movement of said member being determined by the operationof-the selector and by the polarity of current in the line, means for impressing upon the line currents of different polarity and a signal, the operation of which is determined by-that of the selector.

13. In a system of the kind described, the combination of a line, a selector connected to the line and adapted to be actuated by current impulses therein, a member adapted to be moved to two positions, the'movement of said member beingdependent upon the operation of the selector, means whereby themovement of the member is also dependent upon the polarity of current in the line, means for impressing upon the line currents of different polarity, a signal, the operation of which is determined by that of the selector, and a signal, the operation of which is determined by that of said movable member.

14. In a system of the kind described, the combination'of a line, a source of current supply for the line, a pole changer between said source and the line, means for impressing a plurality of impulses upon the line, a selector connected to the line, a member movable to two positions, the movement of said member being dependent upon the operation ofthe selector, and the position assumed depending upon the polarity of current in the line, a semaphore adapted to be moved to two positions, a controlling magnet and a local circuit therefor adapted to be opened or closed according to the position of said movable member, the possibility for movement of said semaphore being dependent upon the operation of said magnet and answerback means the operation of which is controlled by that of the semaphore.

15. In a system of the kind described, the combination of a line, a source of current supply for the line, a pole changer between said source and the line, means for impressing a plurality of impulses'upon the line, a selector connected to the line, a member movable to two positions, the movement of said member being dependent upon the operation of the selector, and the position assumed depending upon the polarity of current in the line, a semaphore and semaphore controlling means, said means includinga magnet and a local circuit therefor adapted to be opened or closed according to the position of said movable member, a local signal the operationfiof which is controlled by that of the selector and answer-back means the operation of which is controlled by that of the semaphore.

16. In a system of the kind described, the combination of a line, a source of current supply for the line, a pole changer between said source and the line, means for impressing aplurality of impulses upon the line, a plurality of selectors connected to the line,

a iliirality of members movable to two positions, the movement of any one of said mem- 'bers being dependent uponihe operation of the corresponding selector'jand the-position assumed by said member depending. ,on ,the. polarity of current in the line, asemapliore for each selector, and semaphore controlling I v means for each semaphor e, said means in-v eluding a magnet and a local circuit therefor adapted to be opened or closed according to the position of the corresponding movable member, a local signal for each semaphore,

. the operation of which is controlled by that of the selector belonging to said semaphore and answer-back means for each semaphore, the operation of which is controlled by that of the semaphore. v

17. In a system of the kind described, the combination of a plurality of semaphores manually movable each to two positions, a line, a plurality of means corresponding respectively to and adapted for rendering said semaphores manually operative and inoperative at will, each of said means including an electro magnet and a local circuit" for said magnet, a plurality of means corresponding to said last-named means and adapted to selectively open and close said local circuits in accordance with the character and polarit of current impulses in the line, and means or impressing upon the line currents of dilierent character and olarity.

18. In a system of the kind described, the combination of a plurality of semaphores manually movable each to two positions, a line, a plurality of means corresponding respectively to and adapted for rendering said semaphores manually operative and inoper ative at will, each of said means including an electro-magnet and a local circuit for said magnet, means corresponding to each semaphore for selectively opening and closing the corresponding local circuit in accordance with the polarity of current impulses in the line, means for impressing upon the line series of impulses, and means for changing the polarity of such impulses.

19. In a system of the kind described, the combination of a line, a plurality of selectors connected to the line adapted to be actuated by current impulses therein, a plurality of signal members adapted to be moved to two positions and corresponding respectively to the selectors, the movement of said members being dependent upon the operation of the corresponding selector, means whereby the position of said members is controlled by the polarity of current in the line, means for impressing upon the line currents of different polarity, a plurality of signals corresponding to, and the operation of which is determined by that of the selectors, the lastmentioned signals being adapted to impress answer-back impulses on said line during their operation and answer-back receiving means in said line.

20. In a system of the kind described, the combination of a line, a plurality of selectors connected to the line adapted to be actuated by current impulses therein, a plurality of signal members adapted to be moved into two positions and corresponding respectively to the selectors, the movement of said members being dependent upon the operation of the corresponding selector, means whereby the position of said members is controlled by the polarity of current in the line, a plurality of signals corresponding respectively to, and the operation of which is determined by that of the selectors, a plurality of signals corresponding respectively to, and the operation of which is determined by that of said signal members the said last two mentioned signals being adapted to impress answer-back impulses on said line during their operation and answer-back receiving means in the line.

21. In a system of the kind described, the combination of a line, a selector connected to the line adapted to be actuated by current impulses therein, a member adapted to ,be moved to two positions, the possibility :ljor movement of sald member being determined by the operation of the selector and by the polarity of current in the line, means for impressing upon the line currents of different polarity, a signal the operation of which is determined b that of the selector,

the said last mentione signal being adapted to impress answer-back impulses on said line during its operation and answer-back receiving means in the line. i

'22. In a system of the kind described, the combination of a line, a signal member adapted to be moved manually into two positions, means for controlling the movements of saidsi al member including a polarized magnet a apted to be shunted into'the line and a local signal in the shunt circuit adapted to indicate the operation of said controlling means.

23. In a system of the kind described, the combination of a line, a signal member adapted to be moved manually into two positions, means 'for controlling the movements of said signal member including a polarized magnet, a normally open shunt circuit on the line for said polarized magnet, a selector permanently connected in the line adapted to close said shunt circuit, answer-back receiving means on the line and means, the operation of which depends upon that of the selector for impressing answer-back impulses upon the line for said receiving means.

24. In a system of the kind described, the combination of a line, a signal member adapted to be moved to two positions, means for controlling the movement of said signal member including a polarized magnet adapted to be shunted into the line, answer-back receiving means on the line and means for impressing answer back impulses upon the line when said polarized magnet has been shunted onto the line.

25. In a system of the kind described, the combination of a line, a signal member adapted to be moved into two positions, means for controlling the movement of said signal member including a polarized magnet adapted to be shunted into the line, an-

swer-back receiving means on the line, and automatically operating means for impressing answer-back impulses upon the line when said polarized magnet has been shunted onto the line.

"26. In a system of the kind described, the combination of a line, a signal member adapted to be moved to two positions, means for controlling the movement of said signal member including a polarized'magnet adapted to be shunted into the line, answer-back receiving means on the line, and a local In testimony whereof I afii'x my signature in the presence of two witnesses,

EDWIN R. GILL.

Witnesses:

FRANK J. KENT, M. A. BUSGHER.

Copies ofthis patent may be obtained for five cents each, by addressing the Commissioner otl'etents.

Washington, D. 0.

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