US2110166A - Signaling system for railway and like installations - Google Patents

Description

arch 8, 1938. I NlCOLAs 2,110,166

- SIGNALING SYSTEM FOR RAILWAY AND LIKE INSTALLATIONS Filed Dec. 4, 1935 2 sheets-sheet 1 INVENTOR= PAUL NICOLAS ATToRN 5Y5 March s, 1938. P LAS 2,110,166

SIGNALING SYSTEM FOR RAILWAY AND LIKE INSTALLATIONS Filed Dec. 4, 1935 2 She'hs-Sheet 2 INV-ENTOR= 7 PAUL NICOLA6 A'ILTORNENS Patented Mar. 8, 1938 UNITED STATES PATENT, OFFICE SIGNALING SYSTEM FOR RAILWAY AND LIKE INSTALLATIONS Paul Nicolas, Paris, France, assignor to Societe Francaise Radio Electrique, a corporation of France Application December 4, 1935, Serial No. 52,838

g In France December 6, 1934 g 11 Claims. (Cl. 246+63) The present invention relates to Signaling systravelling vehicle itself of signal indications tems' for railway and like installations and is which are normally given by indicators arranged particularly applicable to the repetition of sigat intervals along the side of the track. nals in the cabs of locomotives, motor trains and To this end, there corresponds to each signal other vehicles travelling on railway tracks of all indicator located at the side of the track, a parkinds, whether electrified or not, or insulated or ticular electrical combination which is transnot, and provided with either Wooden or metal lated on board the vehicle by an ordinary signal sleepers. (coloured lamp, bell, horn, or the like) according One object of the invention is to provide a sigto a pre-arranged code. This signal is normally 0 naling system for railway and like installations produced at the moment when the vehicle passes of the kind wherein the signals are given under the corresponding indicator position along the the control of an electrical system which protrack. It may, furthermore, be so arranged that vides for the co-operation between elements stathe signal given on the vehicle persists after the tionary along the side of the track and elements indicator position has been passed and has to carried by the travelling vehicle, but which is of undergo a resetting operation carried out by the 15 improved construction and operation over the driver of the vehicle. The production of the systems hitherto proposed. signal and this resetting operation may be regis- Another object of the invention is to provide tered on a band of paper by any known process, an improved electrically operated signaling sysfor example, mechanical, in order to show that tem for railway and like installations involving the signal has been properly produced and has 20 the co-operation of stationary electrical elebeen properly noted. ments provided along the side of the track with The electrical system operates by induction electrical elements carried by the travelling vewithout mechanical contact between the movable hicle whereby the operation of the system is obelements of the apparatus and the stationary ele- 5 tained by means of electric currents of audioments. The stationary apparatus located along frequency and Without depending upon sharp the side'of the track adjacent to the indicators resonance for the successful co-operation of the are composed entirely of inert elements, all the electrical elements. I necessary sources of current being carried on the Another and more specific object of the invehicle. In addition to these advantages which vention is to provide an improved signaling sysare common to other known arrangements, the 30 term for railway and like installations whereby a system according to the invention has also the plurality of different signals may be selectively advantage that the determination of the differgiven on the travelling vehicle by means of an ent signals is not dependent upon sharp resoelectrical system operating by electro-magnetic nances necessitating on the part of the source induction and which provides for the co operaor sources of-alternating current used, great station between elements stationary along the side bility of frequency. Finally, the system may be of the track and elements carried by the travelso arranged that if the mechanism of the signal ling Vehicle but Without depending po Sharp indicator ceases to function the indication given resonance for the successful operation of the 00- on the vehicle is necessarily that of a blocked 40 operating electrical elements. track. a 4

A still further object of the invention is to The number of the separate signals which it is provide an improved signaling system for rail generally desired to repeat on the vehicle is three. way and like installations which is adapted to However, with the arrangement according to the give signal indications on the travelling vehicle invention hereinafter to be described there may by means of an electrical system which provides easily be obtained four distinct indications. It 5 for the co-operation between stationary elements will also be appreciated that there is nothing to provided along the side of the track and further prevent a generalization of the system so that elements carried by the moving vehicle, in comit gives a larger number of indications. bination with means for controlling the said sig- The above and further objects, advantages and nals in accordance with the condition of a track features of the invention will be more clearly 50 section ahead of the track section on which the understood from the description of a preferred travelling vehicle is moving. embodiment thereof, which is given hereinafter,

In carrying the invention into practice, the imbyway of example, with reference to the accompro-ved signaling system according to the invenpanying drawings, in which:

tion provides preferably for the indication on the Figure l is a. general diagram of an installa- 5 tion on the moving vehicle and a circuit arranged at the side of the track,

Figure 2 is a modification of the circuit arranged at the side of the track according to Figure 1,

Figure 3 represents diagrams explaining the operationof the receiver on the vehicle, Figure 4 shows in detail the diagram of the receiver on the vehicle, v

Figure 5 shows a further modification of the circuit arranged at the side of the track; and

Figure 6 shows the signal indicating circuits controlled by the receiver.

With reference to Figure 1,.the signal indicating system comprises:

1. On the vehicle a. A generator of alternating current G usually of single phase supplying a coil S termed the emitter coil. In series with G and S are arranged various electrical elements such as a condenser C, a rheostat Rh, an ammeter D, etc. in order to regulate and control the intensity of the current supplied by G and also to improve the power factor of the circuit.

A receiver R, which will be more fully described hereinafter, is supplied with current derived from G by means of an impedance I connected in series with G and S.

The frequency of the currentgiven by G will preferably be chosen of an average audiofrequency, for example, from 400 to 2,000 periods per second. y

b. A coil F termed the receiving coil.

Under certain conditions, as will hereinafter be described, the receiving coil F is influenced bythe coil S and becomes the seat of an electromotive force. The arrangement is normally such that when S and F are not coupled with other circuits, the electromotive force induced by S in F is small or nil.

The receiving coil F is connected to the receiver R as shown.

c. The receiver R which permits or roughly measuring in value and signthe angle of phase between the electromotive force E induced in F and the primary current Ip supplied by the generator G. The said receiver in turn operates relays which produce on the vehicle desired optical or audible signals.

I 2. On the ground along the track U Two fixed coils A and'B which, when the vehicle passes close to them, are coupled simultaneously with S and F. It is furthermore possible in many cases to replace the two coils A and B by a single coil provided that this is of suflicient geometrical dimensions to be simultaneously .coupled with S and F. Finally, an impedance Z which is of different value according to the signal which it is desired to produce, is connected in parallel with A and B by the mechanism of the track signal indicator.

The difierent coils S, F, A, B, may be provided or not with iron cores.

The operation of the system will readily be understood with reference to Figure 1.

When the unit carried by the vehicle and formed bythe emitter S and the receiver coil F passes in the vicinity of A and B, an induced current is developed in the circuit AB. Owing to the coupling existing between B and F, this induced current influences in its turn the coil F and the receiver R. V

' This being the case, it will beunderstood that the phase angle between the current flowing in the coil B and consequently between the electromotive force induced in the coil F and the current flowing in S, the phase of which is taken as a basis, will depend substantially upon the nature and the value of the impedance Z.

In a general manner, the coils A and B will be so constructed as to present a considerable excess potential that is to say that the ratio of their selfinduction to their resistance will be such that at the frequency of the current supplied by the generator G, the counter electromotive force due to the self-induction of the coil is in absolute value several times greater than that due to the ohmic resistance.

Under these conditions, if no impedance Z is interposed, the current in the coil B will be approximately in phase, for a suitable choice of the directions of winding of the coils, with the primary current flowing in S.

If, on the contrary, there is interposed at Z a capacitative reactance of small value compared with the inductive reactanceof the coils A and B, the current flowing in B will be approximately in phase opposition with the current in the emitter core S.

If there is interposed, on the other hand, at Z a resistance without appreciable self-induction or capacity and of small value as compared with the reactance of the coils A and B, the current in B will be approximately lagging by a quarter of a 7 period behind the primary current in the emitter coil S.

Finally, in order to cause the current in B to lead by a quarter of a period on the current in S, a slightly more complicated arrangement will be employed which comprises the use of a third coil A1. The operation of this arrangement will readily be understood with reference to Figure 2. When it is desired to produce this combination, it will be arranged that the mechanism of the track signal indicator connects a small resistance Z1 in parallel with A and places in circuit instead thereof a third coil A1 of mechanical and electrical dimensions similar to those of A and located in its immediate vicinity without being strongly coupled therewith. A1 is Wound oppositely to A. In a modification of the same method, a similar operation could be carried out by inserting in the circuit a coil Wound in an opposite direction in the place of coil B influencing F. As the circuit would otherwise be identical with that of Fig. 2, except for the opposite winding on the mentioned coil replacing coil B, it is thought superfluous to illustrate such an obvious and slight variation. In either case, it is clear that if Z1 is a resistance having the same value as in the third case, the desired result will be attained.

The problem of the repetition of the signals on the vehicle then resolves into the construction of a device adapted to measure the phase angle existing between the primary current Ip of the emitter S and the electromotive force collected in the coil F. Figure 3 shows the value of this phase angle in the different cases. In this figure, the electromotive force E collected in F is represented by a vector (0E1, 0E2, 0E3, 0E4, according to whether the first, second, third or fourth case is being dealt with). This electromotive force is, of course, in advance by a quarter of a period on I the current in the coil B.

This being the case, let there be drawn on Figure 3 two straight lines X1OX,Y1OY at an angle of 45with respect to 0E1, OEaOEs and DB4, and let it be imagined that a suitable electrical arrarigement actuated both by the primary current Ip and the electromotive force OE, effects the excitation of a relay R1 when OE is in the half plane below the straight line X1OX, but this relay is not excited when the vector OE is above this line. Let it be supposed also that a second relay R2 is excited when the vector OH. is below the line YOY1 but that it is not excited when the vector OE is above this line.

It will easily be seen that such relays can be connected to close contacts controlling coloured lamps, bells, etc.

Given the above arrangement, it will now be seen that in the first case above mentioned, this will result in both R1 and R2 being de-energized. In the second case, R1 will be de-energized and. R2 will be energized. In the third case, both R1 and R2 will be energized, and in the fourth case R1 will be energized and R2 will be de-energized.

Three of the above four cases may be made to correspond in any suitable manner to the three signals which it is desired to reproduce. Preferably, the first mentioned case will be chosen to represent the signal line blocked so that an accidental failure of current in the relays or a bad contact on the impedance Z will not give any other indication.

' In Figure 41, there is illustrated by way of example, one manner of constructing the phase selecting device which permits of controlling the relays R1 and R2.

In the embodiment illustrated in Figure 4, the receiving coil F is shunted by a condenser C and a resistance 7*, this arrangement having for effect to select by the known method of resonance or tuning in the circuit of F, the electromotive force E due to the coupling between S and AB with respect to other accidental electromotive forces which may be induced, and also to strengthen the current in the circuit of F. The resistance 1' will nevertheless be given a value sufficiently small to avoid the resonance being too sharp and the possible Variations of frequency of the generator G having an influence on the operation of the arrangement. There is also connected to the terminals of the receiving coil F the primary windings of a transformer T provided with two identical secondary windings. On the other hand, the primary current Ip of the emitter passes through the impedance I which is formed by a self-induction coil L, two resistances TI and T2 and a condenser C1 all connected in series. The values of L, r1, T2, and C1, may be so chosen that the sums of the potentials at the terminals of L and T1 on the one hand and of T2 and C1 on the other hand, are approximately equal and displaced in phase by -4=5 degrees with respect to the primary current and therefore by 90 degrees between themselves. 1

These potentials supply respectively the primary windings of two transformers T1 and T2, the secondaries of which are formed by two equal half windings which produce potentials of equal value but of opposite phase.

It will be seen from the connections of Figure 4 that each of the units formed by the secondary of one of the transformers T1 or T2 and one of the secondaries of the transformer T supplies a system of two rectifying devices V (thermionic valve or metallic rectifier). Each of these systems supplies a rectified current to the resistances W shunted by the condensers K. If the different elements of the same name (W or K) are truly equal to one another, it will easily be seen that no rectified continuous potential will appear between the points M1 and N1 for the electromotive force of which the coil F is the seat will have its phase shifted by +45 or -135 with respect to the primary current Ip, because at this moment the tensions introduced into the secondaries of the transformer T1 by the secondary of the transformer T exactly compensate for the tensions induced in the two halves of the secondary T1 by the primary of this transformer. In the same way, as regards the difference of potentials between the points M2 and N2, it will be zero when the phase between the electromotive force at F and the current I is -45 or +135", because an exact compensation takes place at this moment in the half-secondaries of the transformer T2. With suitably selected directions of winding primaries and secondaries of the transformers T, T1, T2, it can be arranged that there is obtained, for example, at M1 and N1 a positive potential when in Figure 3 the vector OE is situated in the half plane below the straight line XIOX (phase angle less than +45 or 135, and negative in the contrary case. Corresponding conditions can also be obtained for M2N2 and Y1OY (the tension being positive for example for a phase angle less than 45 or +135).

If the relays R1 and R2 were sufficiently sensitive, these could be connected respectively between M1 and N1 and M2 and N2. In practice, however, it is found preferable to effect this connection through a triode amplifying valve or a gaseous discharge tube called an ionized-gas grid-controlled relay and which is represented at Th on the drawings. For example, the point M1 will be connected to the grid of the Thyratron valve and N1 to its cathode. When an ionized-gas grid-controlled relay is employed, it is preferable to connect the point M1 to the grid through a fairly high resistance 13, the resistance of the grid-filament space of an ionized-gas grid-controlled relay being adapted to be small when a considerable current flows between the anode and cathode.

It will furthermore be noted that by giving sufficiently high values to the capacities K, it is possible to obtain an operation of the arrangement such that these capacities are charged in a short time under the action of the transformers T, T1, and T2 and rectifying elements V, while their discharge through the resistances W only takes place slowly if the resistances W are of high value. This feature is of importance because when the vehicle is travelling at a high speed, the duration of the action between the coils A, B and S, F is small.

The arrangement is completed by the two relays R1 and R2 being excited by the anode current of the ionized-gas grid-controlled relay valve Th, the plate circuit of which is supplied, for example, by the secondary of a transformer T3, the primary winding of which is supplied by the generator G. The relays will then operate on failure of current when OE is in the half plane located above X1OX or YOY1.

Figure 6 represents the circuits controlled by the relays R1 and R2. As shown, the relay R1 is provided with three armatures l, 2, 3. The role of the armatures I and 2 will be explained more fully hereinafter while the armature 3 which oscillates between two pairs of contacts serves to control the signaling circuits. The relay R2 is provided with five armatures 4, 5, 5, I, 8. The armature 4 is utilized in combination with the armature 2 and itsoperation will be explained more fully hereinafter. The armatures 5, 6, 1, 8

togetherwith the armature 3 control the signaling circuits, each armature closing a contact in the position of rest or of working. The signal indicating devices (lamps, horns or the like) are shown at 9, l0, H, and I2 and are supplied from a suitable source I3. It will be seen from the connections of the contacts of the two relays that when R1 and R2 are de-energized, the armatures 3 and 6 close the circuit of the indicating device i I which then operates. The simultaneous energization of R1 and R2 effects the closing through the armatures 3 and of the circuit of the indicating device l2. If the relay R1 is energized alone and R2 is de-energized, the armatures 3 and 8 close the circuit of the indicating device 9. Finally, if R2 is energized and R1 is de-energized, the armatures 3 and I close the circuit of the indicating device In. Thus, a different indicating device is operated for each combination.

Naturally, in place of the arrangement described, any other means may be employed for detecting the phase of the electromotive force in the coil F with respect to the current Ip. For example, a device similar to a watt meter or the like may be used.

An important application of the signaling arrangement, the principle of which has been explained above, consists in combining the same with the signaling arrangement forming the object of my oo-pending application No. 15,962 of 12th April 1935, which device hasfor its object to reveal the presence in front of the vehicle equipped therewith, of another vehicle the axles of which close the track circuit which is the seat of the currents induced by the emitter of the first vehicle.

The arrangement in said application consists in inducing the current in the rails through a coil similar to S, collecting this current by means of a coil similar to F and measuring by means of a receiver similar to R the phase displacement between the current supplied by a generator similar to G and the current received, this phase displacement being variable with the distance from the short-circuit of the track.

The coils S and F must then be located on the vehicle in such manner as to be'coupled with the track circuit as strongly as possible. This modification can naturally only be employed if the track has insulating sleepers and if the joints of the rails are sufficiently electrically conductive.

In this case there will be used three ofthe four proposed positions of the vector OE for the repetition of the three signals line clear, "warning, line blocked, the fourth position corresponding to the operation of the arrangement forming the object of my co-pending application aforesaid. An interesting advantage of the above described arrangement is that it is then possible to produce the signal line block by using the mechanism of the track signal indicator to short circuit the track, which has the advantage that the signal line blocked is produced not only on passing the said signal indicator but also at a certain distance before reaching the same.

Nevertheless, when it is desired to carry the said combination into practice, it will be preferable to slightly modify the constitution of the circuit of the coils A and B since otherwise a certain confusion might result between the signal line blocked and the signal given by the presence of another vehicle on the track, due to the impedance of the track circuit then being of a nature similar to that of the simple circuit formed by the coils A and B in series.

To this end, there may then be used, for example, the arrangement according to Figure 5. The coils S and F are coupled, on passing a track signal indicator, with the coils A and B as in Figures 1 and 2. In addition however, they are also strongly coupled with the track indicated at V, which may be short circuited in front of the vehicle by another vehicle or at M by a mechanism controlled by another signal indicator or from a signal box. There is connected in series with each of the coils A and B a resistance W1 and a capacity K1 of suitable values. The capacity will be chosen in such manner that the unit formed by the self-induction of the coil and the capacity K1 in series therewith is approximately tuned to the frequency of the current supplied by the generator G. The resistance W1 serves effectively to damp the system so as to avoid the possible influence of variations of frequency of G. It will readily be understood that in this case, when no impedance Z is connected in the circuit, the electromotive force induced by B in the coil F is in quadrature with that produced by the track current and the two signals closed line and train ahead cannot therefore be confused. This arrangement will be chosen for the repetition of the signal line blocked.

By giving a suitable value to Z (capacitative or self-inductance reactance according to the relative sense of the couplings of S and F with the track circuit and with the coils A and B) there may be produced a signal opposite in phase to that which is given by the current in the track circuit. Finally, by using in a similar manner to that of Figure 2, a second coil A1 of opposite winding to A, there may be obtained a signal in phase opposition to that which corresponds to the blocked track (Figure 5). A1, like A, will be connected in series with a capacity K1 and a resistance W1, and the impedance Z1 introduced by the contact controlled by the track signal indicator will be a resistance of small value.

As it is desirable, at least for the most important indications such as line closed and warning, that. the signal indication on the vehicle should not disappear as soon as the corresponding track signal indicator has been passed, it will be of advantage to use for one at least of the relays R1 and R2 a relay of the type known as guarded. This term is given to a relay which after having been deenergized cannot become energized again by itself. To efiect this, it is sufficient, for example, for the de-energization to close a contact short-circuiting the coil of the relay.

Let it be supposed, for example, that the following code has been adopted:

1.-Line blocked: R1 and. R2 de-energized.

2,"Warning: R1 de-energized, R2 energized.

3.Line clear: R1 and R2 energized.

4.--Track current (vehicle in front) R1 energized, R2 de-energized.

It will then be of advantage to adopt the arrangement that R1 is a guarded relay and is provided furthermore with a system of contacts such that when R1 and R2 are simultaneously de-energized, R2 also cannot energize itself again. When R1 is energized, R2 will not be guarded. The fourth indication given by the track current is in fact of a continuous character and is not transitory like that which is produced on passing a track signal indicator.

With reference once more, to Figure 6, it will be understood that this figure shows an arrangement according to the above explanation. The armature l of the relay R1 short-circuits the coil of this latter when it is de-energized. The armature 2 is in series with the armature 4 of the relay R2. These two armatures close a circuit short circuiting the coil of R2 when the two relays are de-energized. The arrangement can only be set in operation again when the cause of the deenergization of the relays disappears and the contacts I, 2, and 4 are opened, for example by hand by means of a push button, not shown.

The principle of the system of the repetition of signals which has just been described may of course be extended to a number of signals greater than four. The vector OE: could, for example, be given six positions separated by sixty degrees,

by utilizing three relays or any other similar arrangement. It will therefore be understood that the invention is in no way limited to the particular arrangements above described but comprises all modifications thereof within the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States is:-

1. A signaling system for railway and like installations in which a vehicle travels along a predetermined track, comprising a first electrical system carried by said vehicle including an alternating current generator, an emitter coil in the circuit of said generator, a receiver coil located so as to avoid inductive coupling with said emitter coil and a receiver connected to be supplied differentially by said generator and by said receiver coil and comprising means for measuring the difference of phase between the electromotive force in said receiver coil and said generator current, and a stationary electrical system located alongside said track and comprising two inductances forming a closed circuit and means for controllably connecting a common impedance in shunt across each of said inductances, said inductances of said stationary system becoming coupled respectively with said emitter and receiver coils of said system carried by said vehicle when said vehicle passes along said track so that an electromotive force is induced in said inductances by said emitter coil, which electromotive force in turn induces an electromotive force in said receiver coil of said first mentioned system which is supplied to said receiver.

2. A signaling system for railway and like installations in which a vehicle travels along a predetermined track, comprising a first electrical system carried by said vehicle including a generator of alternating current of audio frequency,

an emitter coil in the circuit of said generator,

a receiver coil located so as to avoid inductive coupling Withsaid emitter coil, and a receiver connected to be supplied difierentially by said generator and by said receiver coil and comprising means for measuring the difi'erence of phase between the electromotive force in said receiver coil and said generator current and means responsive to an audio frequency current for giving an indication in accordance with said phasedifference, and a stationary electrical system located alongside said track and comprising two inductances forming a closed circuit and means for controllably connecting a common impedance in shunt across each of said inductances, said inductances of said stationary system becoming coupled respectively with said emitter and receiver coils of said system carried by said vehicle when said vehicle passes along said track, so that an electromotive force is induced in said inductances by said emitter coil, which electromotive force in turn induces an electromotive force in said receiver coil of said first mentioned system which is supplied to said receiver.

3. In a signaling system for railway and like installations in which a vehicle travels along a predetermined track and a signal indication is given by induction between an electrical system carried on said travelling vehicle and a stationary electrical system located alongside said track, said stationary electrical system located alongside said track comprising two inductances forming a closed circuit and means for controllably short circuiting each of said inductances by an impedance.

4. In a signaling system for railway and like installations in which a vehicle travels along a predetermined track and a signal indication is given by induction between an electrical system carried on said travelling vehicle and a stationary electrical system located alongside said track, said stationary electrical system located alongside said track comprising two inductances in series, means for short circuiting each of said inductances by a common impedance and means for additionally inserting in the circuit instead of one of said inductances a further inductance wound oppositely to the said last inductance.

5. In a signaling system for railway and like installations in which a vehicle travels along a predetermined track and a signal indication is given by induction between an electrical system carried on said travelling vehicle and a stationary electrical system located alongside said track, said stationary electrical system located alongside said track comprising at least two inductances in series, means for short circuiting each of said inductances by a common impedance, and a resistance and a capacity connected in series with each of said inductances.

6. A signaling system for railway and like installations in which a vehicle travels along a predetermined track provided with a track signal indicator, comprising a first electrical system carried by said vehicle including an alternating current generator, an emitter coil in the circuit of said generator, a receiver coil located so as to avoid inductive coupling with said emitter coil, and a receiver connected to be supplied differentially by said generator and by said receiver coil and comprising means for measuring the difierence of phase between the electromotive force in said receiver coil and said generator current, and a stationary electrical system located alongside said track and comprising at least two inductances in series and means controlled by said track signal indicator for short circuiting each of said inductances by a common impedance and for additionally inserting in the circuit instead of one of said inductances a further inductance wound oppositely to the said last inductance, said inductances of said stationary system becoming coupled respectively with said emitter and receiver coils of said system carried by said vehicle when said vehicle passes along said track, so that an electromotive force is induced in said inductances by said emitter coil, which electromotive force in turn induces an electromotive force in said receiver coil of said first mentioned system which is supplied to said receiver.

installations in which a vehicle travels along a' predetermined track provided with electrically insulating sleepers, comprising a first electrical system carried by said vehicle including an alternating current generator, an emitter coil in the circuit of said generator, a receiver coil located so as to avoid inductive coupling with said emitter coil and a receiver connected to be supplied differentially by said generator and by said receiver coil and comprising means for measuring and indicating the difierence of phase between the electromotive force in said receiver coil and said generator current, and a stationary electrical system located alongside said track and comprising two inductances and means for controllably connecting an impedance in circuit with said inductances, said inductances of said stationary system becoming coupled respectively with said emitter and receiver coils of said system carried by said vehicle when said vehicle passes along said track, so that an electromotive force is induced in said inductances by said emitter coil which electromotive force in turn induces an electromotive force in said receiver coil of said first mentioned system which is supplied to said receiver, and means for additionally controlling the indications given by said receiver in accordance with the condition of a track section ahead of the track section on which said vehicle cooperates with said stationary system alongside said track.

3. A signaling system for railway and like installations in which a vehicle travels along a predetermined track provided with electrically insulating sleepers comprising a first electrical system carried by said vehicle including an alternating current generator, an emitter coil in the circuit of said generator, a receiver coil located so as to avoid inductive coupling with said emitter coil and a receiver connected to be supplied differentially by said generator and by said receiver coil and comprising means for measuring and indicating the difference of phasebetween the electromotive force in said receiver coil and said generator current'and means for coupling said coils with said rails so that said receiver also indicates a short circuit of the track section in front'of the track section occupied by said vehicle, and a stationary electrical system located alongside said track and comprising at least two inductances in series, a resistance and a capacity in series with each of said inductances, and means for controllably short circuiting each of said inductances by a common impedance, said inductances of said stationary system becoming coupled respectively with said emitter and receiver coils of said system carried by said vehicle when said vehicle passes along said track, so that an electromotive force is induced in said inductances by said emitter coil, which electromotive force in turn induces an electromotive force in said receiver coil of said first mentioned system whioh is supplied to said receiver.

9. In a signaling system for railway and like installations in which a vehicle travels along a predetermined track and a signal indication isgiven by induction between an electrical system carried by said travelling vehicle and a stationary electrical system located alongside said track, an apparatus on said vehicle comprising an alternating current generator, an emitter coil in the circuit of said generator, a receiver coil located so as -to avoid inductive coupling with said emitter coil, an impedance energized by said generator and comprising a series of partial im pedances, the voltages at each of said partial impedances presenting between themselves and with respect to said generator current predetermined phase displacements, a transformer supplied by each of said voltages and having a corresponding number of secondary windings, the extremities of each of said windings of said transformer being connected to a circuit composed of two series connected units each comprising a resistance shunted by a capacity, a connection from the mid point of each of said secondary windings to the junction of the corresponding resistance capacity units, means for introducing into each of said connections a voltage furnished by said receiver coil, and signal indicating means connected to said resistance capacity-unit circuits.

10. In a signaling system for railway and like installations in whicha vehicle travels along a predetermined track and a signal indication is given by induction between an electrical system carried by Said travelling vehicle and a stationary electrical system located alongside said track, an apparatus on said vehicle comprising an alternating current generator, an emitter coil in the circuit of said generator, a receiver coil located so as to avoid inductive coupling with said emitter coil, an impedance energized by said generator and comprising a series of partial impedances, the voltages at each of said partial impedances presenting between themselves and with respect to said generator current predetermined phase displacements, a transformer supplied by each of said voltages and having a corresponding number of secondary windings, the extremities of each of said secondary windings of said transformer being connected to a circuit composed of two series connected units each comprising a resistance shunted by a capacity, a connection from the mid point of each of said secondary windings to the junction of the corresponding resistance capacity units, means for introducing into each of said connections a voltage iurnished by said receiver coil, means for collecting at the output of said receiver a number of voltages representing a predetermined signal, electromagnetic relays controlled in accordance with said voltages, and a circuit comprising a plurality of signal indicators and the contacts on said electromagnetic relays so connected as to render each of said signal indicators operative for a different predetermined combination of energization of said electromagnetic relays. 1

11. A signaling system for railway and like installations in which a vehicle travels along a predetermined track provided with a track signal indicator, comprising a first electrical system 'located alongside said track and comprising two inductances and means controlled by said track signal indicator for connecting an impedance in circuit with said inductance, and a second electrical system carried by said vehicle including a generator of alternating current of audio frequency, an emitter coil in the circuit of said generator and a receiver coil located so as to avoid inductive coupling with said emitter coil, so that said inductance of said stationary system alongside said track becomes coupled respectively with said emitter and receiver coils of said system carried by said vehicle when said'vehicle passes along said track, whereby an electromotive force is induced in said inductances by said emitter coil, which electromotive force in turn induces an electromotive force in said receiver coil of said first mentioned system which is supplied to said receiver, a receiver supplied difierentially by said generator and by said receiver coil and comprising means for measuring the diiTerence of phase between the electromotive force in said receiver coil and said generator current and means responsive to an audio frequency current for giving an indication in accordance with said phase difference, said two last mentioned means comprising an impedance energized by said generator and comprising a series of partial impedances, the voltages at each of said partial impedances presenting between themselves and with respect to said generator current predetermined phase displacements, a transformer supplied by each of said voltages and having a corresponding number of secondary windings, the extremities of each of said secondary windings of said transformer being connected to a circuit composed of two series connected units each comprising a resistance shunted by a capacity, a connection from the mid point of each of said secondary windings to the junction of the corresponding resistance capacity units, means for introducing into each of said connections a potential drop furnished by said receiver coil, means for collecting at the output of said receiver a number of voltages representing a predetermined signal, grid controlled valve relays supplied respectively by said voltages, electromagnetic relays controlled by said ionized gas valve relays and a circuit comprising a plurality of signal indicators and the contacts of said electromagnetic relays so connected as to render each of said signal inv dicators operative for a difierent predetermined combination of energization of said electromagnetic relays.

PAUL NICOLAS.

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