|Publication number||US1328865 A|
|Publication date||Jan 27, 1920|
|Filing date||Oct 18, 1915|
|Publication number||US 1328865 A, US 1328865A, US-A-1328865, US1328865 A, US1328865A|
|Inventors||Charles H. Woodward|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (6), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
C. H. WOODWARD.
TRAIN SIGNALING AND TRAIN CONTROL SYSTEM.
APPLICATION FILED OCT. 18. 1915.
Patented Jan. 27, 1920.
1 mil/L17 CHARLES WOODWARD, OF BOURNEMOUTH, ENGLAND.
TRAIN-SIGNALING- .AND TRAIN-CONTROL SYSTEM.
Specification of Letters Patent.
Patented Jan. 27, 1920.
Application filed October 18, 1315. Serial No. 56,649.
To all whom it may concern:
Be it known that I, CHARLES HnMLn'r Wooownno, a citizen of the United Kingdom, residing at 15 Richmond Park Crescent, Bournemouth, in the county of Hampshire, England, have invented a new and useful Train-Signaling and Train-Control System, of which the following is a specification.
This invention relates to a novel train signalii'lg and train control system, and according to the invention the indicating or controlling circuit on the train is energized by the instantaneous difference of potential between the points of a track rail or between two rails on which high frequency alternating current is impressed by suitable means, the said circuit being tuned in resonance with the periodicity of the alternation. If one end of the track rail is directly connected to the source of the high frequency current the other end may be grounded over a condenser of adjustable capacity. In this case the track rail forms part of a closed oscillatory circuit with practically no radiation; or where a closed oscillating circuit is used as a generator, the tuning condenser may be omitted when the rail will operate as a coupling between the generating and receiving circuits. The train carried indicating or power con trolling devices are inserted in a circuit connected to two points on the track rail or rails from which the high frequency current can be collected by conductors carried by the train running on the rail or rails. For example, the circuit can be completed through the trainwheels or other conductors running on the track, and if completed through the wheels, the circuit can be traced from one wheel through its axle box to the indieating or control devices back to the rail through another wheel and its axle box. Owing to the well known skin eflect of an iron conductor on which high frequency oscillations are impressed, caused by the high impedance. a considerable difference of potential will obtain between two points at a comparatively small distance apart, with an alternating current of high frequency, thereby causing the connected circuit to swing powerfully when tuned.
The arrangement is preferably such that safety conditions are indicated by the pres ence of current in the receiving circuit and, conversely, danger conditions by the absence of such current; such absence of current being caused by switch operation, breakage of apparatus, detuning of the resonant circuit or circuits.
When more than one independent signal is required, each track rail may be connected, as described above, but the oscillations impressed on the two rail circuits will be tuned to different frequencies to avoid resonant interference between the two circuits. Therefore, both rails or sections may be used separately or together.
A third independent set of signals may be obtained by joining the two track rails or sections through a condenser at the end of a section and tuning its train carried receiving circuit to a suitable frequency of this closed circuit to avoid resonant interference with the other circuits. Or, if the rail be used as a common coupling between the receiving circuits and a closed generating circuit, the condenser may be omitted and the rails directly connected. The receiving circuit will have a portion consisting of axle, truck, or other metallic framework common to itself and the rail circuit, and must in either case be tuned to a frequency different from that impressed on either rail separately and such as to avoid resonant interference with the other rails or sections. It is obvious that this set of signals can be received independently of those transmitted over either or both of the separate rails. Also, one or both rails may be cut at any point and signals received over that par ticular length of rail. For the purpose described or for additional signal indications or the like, one or both rails or sectionsmay by known arrangement be cut at any point and used in the aforementioned manner for the purpose of interlocking the operations of the aforementioned signal or the like indications or control and use may be made of high frequency alternating current whereby a train in a given blo k may cut off or control the power in a block in the rear and also. if desired, any other section in the rear or advance.
It is well understood that a change in the length of rail over which the current would pass would cause an increase in the frequency of the current in the track circuit, hence, inasmuch as the cab circuit is normally tuned to the frequency impressed on the track rail under clear conditions it must,
in view of what has just been said, be neces sarily tuned to the lowest frequency impressed on the track rail.
The signals received ma be used in known manner to apply the bra es, to control the motive power applied to the train, or give audible indications by means of bells or whistles, or visual indications by lamps or the like or otherwise.
The accompanying drawings represent diagrammatically examples of circuit arrangements embodying my invention.
In said drawings:
Figure 1 illustrates an arrangement in which the train carried circuit is energized by the potential difference between points on the mine track rail.
Fig. 2 illustrates an arrangement in Which the train carried circuit is energized by the potential difference between points on two track rails.
As shown in said drawings, and referring more particularly to Fig. 1, 10, 11 designate the track rails and 14, 15 designate, respectively, the front and rear axles of a portion of a train traveling on said track rails. 16, 16 designate low tension alternatin electric current leads and 17 and 18 designate, respectively, the primary and secondary windings of a ste -up transformer, in which the primary win ing is connected across the leads 16. 19 designates a spark gap in the secondary circuit of the transformer; 20 an adjustable condenser in said circuit and 21 an inductive resistance in the circuit traversed by the high frequency oscillations set up by the spark gap. These oscillations are impressed on the track rails and adjustable condensers 22 are connected to the rails at a distant point. The condensers may be connected to ground. As shown in Fig. 1, the rails 10 and 11 are respectively parts of separate circuits through which two train carried circuits may be simultaneously energized, but either of the energizing circuits may be used to the exclusion of the other.
In the arrangement shown in Fig. 2, high frequency oscillations are additionally impressed On the two track rails 25, 26, which rails may be connected at a distant point through an adjustable condenser 27. An inductive resistance 28 and a spark gap 29 is connected between the rails. In other res ts the arrangement shown in Fig. 2 is like that shown in Fig. 1, and the operation in Fig. 2 is modified with respect to Fig. 1 in the manner hereinafter described.
Referring again to Fig. 1, it will be noted that the train carried circuit or circuits is energized by the instantaneous potential difference between the points on the track rail or rails in electric connection, respectively, with the axle boxes or axles 14 and 15, through the wheels of said axles which travel on the said rails or through other conductors that travel on the track rails.
Each said train carried circuit comprises an inductance 30, an adjustable condenser 31, and a relay coil 32. Each circuit is tuned to the frequency of the oscillations impressed on its corresponding rail to avoid resonant interference. When the relay windings 32 are energized an audible or visual signal may be operated in any well known manner by completing the circuit of a battery 33, thereby operatlng a member 3-1, diagrammatically shown, whlch member may be operated to control a visual or audible signal, or may also be arranged in any well known manner to apply the brakes or control the motive power applied to the train, one of said members 34 being adapted to a signal and the other to a control device.
The train controlled circuit shown in Fig. 2 is similar to that shown in Fig. 1, with the exception that it further embraces a third circuit that is energized by the potential difference between two points respectively on the track rails 25 and 26, in electrical connection respectively with the boxes of the axle 15 or other conductors that travel in contact with the rails. The third circuit will, of course, be tuned to its actuating circuit to avoid resonant interference with the other circuits.
Instead of the track coupling shown in Figs. 1 and 2, between the spark gap circuit and the track circuit, an oscillation transformer may be introduced between the two circuits in the manner usual in transmission or reception of electro magnetic 00 waves for signaling without wires. In this event, the condenser 22 of Fig. 1 may be omitted.
It is obvious that any method of generating high frequency current may be em- 105 ployed without departing from the primerples of the invention.
I claim as my invention:
1. A system of electric signaling or power control comprising means to impress high 110 frequency oscillations on the track rail, and a train carried circuit having contacts to travel on the track rail and energized by the instantaneous potential difference between two points of the rail engaged by 115 said contacts, the train carried circuit being tuned to the frequency of the rail circuit.
2. A system of electric signaling or power control set forth in claim 1, wherein each of two track rails are traversed by current 120 of different periodicities and the rail circuits are tuned similarly to the train carried circuits to avoid resonant interference.
3. A system of electric signaling or control set forth in claim 1 wherein both track 125 rails form part of a circuit tuned to a frequency different from the circuit comprising a single rail only.
4. A system of electric train signaling or power control comprising, in combination 130 with a track rail, means to include said rail as a part of a closed oscillatory circuit and a circuit carried by the train in contact with and tuned to resonate with the closed oscillatory rail circuit.
5. In a system of electric train signaling or power control, means to include the rail of the track as part of a closed resonant oscillatory circuit, said resonant circuit becoming detuned to indicate danger conditions.
6. A system of electric train signaling or power control comprising means to impress high frequency oscillations on the two rails of the track, the frequency in the track circuit being controlled by the presence of a train in the rail block.
7. In a system of electric train signaling or power control, means to include the two rails of the track as part of a closed resonant oscillatory circuit, and a train carried circuit having contacts to travel on the track rails and energized by the instantaneous potential difference between points on the rails engaged by said contacts.
8. A system of electric cab signaling 01' power control comprising means to independently impress on the two rails of a track high frequency oscillations of different periodicity, adapted for use in connection with a plurality of circuits carried by a train or trains on the track, respectively, tuned in resonance to the high frequency oscillations of the two track circuits.
9. A system of electric cab signaling or power control comprising an adjustable condenser connected to the rail and to the ground, means to impress high frequency oscillations on the rail at a point distant from the condenser, and a circuit carried by the train and energized from the track rail the train carried circuit being tuned to the high frequency oscillations.
10. A system of electric signaling or power control set forth in claim 1, wherein the train carried circuit is tuned to the lowest frequency of the rail circuit.
C. H. WOODWARD.
lVitnesses HARVEY J. BAvERs'rooK, CHARLES BLACK.
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|U.S. Classification||246/30, 246/63.00R, 340/310.11, 340/12.32|