US1083306A - Electric signaling system. - Google Patents

Description

J. D. TAYLOR.

ELEGTRIO SIGNALING SYSTEM.

APPLICATION FILED APR. 18, 1908.

Patented J an. 6, 1914.

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ELEGTRIO SIGNALING SYSTEM.

APPLIUATION FILED APR.18. 190B.

1 83,306. Patented Jan. 6, 1914.

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COLUMBIA PUNOGRAPH COUWASHINGTONI D C- UNITED STATES PATN T FIQE.

JOHN D. TAYLOR, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SVVISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

ELECTRIC SIGNALING SYSTEM.

To all whom it may concern:

Be it known that I, JOHN D. TAYLOR, of Edgewood Park, Allegheny county, Pennsylvania, have invented a new and useful Electric Signaling System, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is a view showing diagrammatically one embodiment of my invention; Fig. 2 is a similar diagram showing the presence of a train in one of the blocks; Fig. 3 is a side View showing the manner of increasing the impedance of portions of the track rails; Fig. 4: is a section on the line IVIV of Fig. 3; and Fig. 5 is a detail view of one of the plates or laminae.

This invention has relation to block sig naling systems, more particularly designed for use on railroads employing electric propulsion, and to that class of such systems in which the track rails instead of being separated into insulated blocks or sections are electrically continuous for both signaling and propulsion currents. The term block and sections as used herein and in the claims, are therefore not intended to designate actually separated blocks or sections of the track, but are used for convenience to designate the portions of the tracks which are between adjacent signals.

The present invention is an improvement upon the apparatus described and claimed in my Patent No. 882,27 6, and is designed to provide means of improved character for increasing the impedance of the rails to the flow of alternating current therein.

When an alternating current flows through a conductor, it meets with impedance which is a compound of the ohmic resistance of the conductor and a reactance due to the magnetic field surrounding the conductor. If the medium surrounding the conductor is composed of iron, the reactance and therefore the impedance is very much greater than it would be if the space were occupied only by air or other non-magnetic substance. vVhen an alternating current flows in a track rail, the current of the central portion meets with a very large impedance due to the fact that it is surrounded by iron, while the current in the surface portion of the rail is impeded to a very Specification of Letters Patent. Application filed April 18, 1908.

Patented Jan. 6, 1914. Serial No. 427,833;

much less extent because it is not surrounded by iron.

My present invention is designed to provide means of simple and efficient character, whereby as much as possible of the track rails may be surrounded at certain points with iron for the purpose of increasing the impedance of those portions of the rails. This iron is preferably laminated to prevent loss from eddy currents and to prevent the current which should be confined to the rail from leaving it and flowing through the surrounding envelop. In a rail equipped in this manner, the only part of it in which the current can flow unimpeded is the surface portion along the top and one side of the head of the rail with which the wheels of the train come in contact. This part is, however, only a small fraction of the entire perimeter of the rail section, and consequently the resistance and impedance of the rail is very greatly increased, thereby making the block limits of the system more determinate, as described in my said patent.

The precise nature of my invention will be best understood by reference to the accompanying drawing diagrams, in which I have shown one embodiment thereof, it being premised, however, that various changes may be made therein by those skilled in the art without departing from the spirit and scope of my invention as defined in the appended claims.

In these drawings, the letter A indicates a generator for supplying the propulsion current, and which may be either a direct current generator or an alternator. One terminal of this generator is connected to the usual third rail or trolley wire it, and the other terminal is preferably connected to a conductor m which connects the two rails of the track.

B is an alternating current generator for supplying the signaling circuit. This generator should be adapted to give a current of considerably higher frequency than the generator which supplies the propulsion current where that generator is an alternator. The current from the generator 13 is led to the various signaling instruments by means ofthe line wires or conductors j, is. C and C designate transformers whose primaries p, p are connected across the conductors j, is, and whose secondaries s, s are connected across the track rails r, r, at as nearly as maybe the middle point of the blocks which they respectively supply. The rails 0 r are electrically continuous for all currents. Those portions of these rails at and adjacent to each end of each block are provided with means for increasing their impedance, as indicated at g, g. This may be conveniently eifected by adding iron to each side of the rails between their heads and flanges, this added iron being preferably in the form of relatively thin plates or laminae 9 having portions which fit between the base and head flanges of the rail, and which also extend around the base flanges and underneath the base of the rail. At the opposite side of the rail are a series of plates or laminae g, which are secured to the plates or laminae g by the bolts 9"; The plates or laminae g and the plates or laminae g are secured together by means of through-bolts g". The laminae g are preferably at the outside of the rail, and are made to extend upwardly to within a short distance of the top of the rail head so as to surround as much of the rail as possible with the iron. This added iron acts to increase the impedance of the rails by forming a complete magnetic circuit around the current carried by the rails, and in efiect multiplies their impedance many times. These reinforced sections of the rails are located, as stated, at the ends of the blocks opposite the signals S, S. The relays which control these signals are connected across the rails at the extreme ends of the reinforced sections. These relays are designated by the letters R, R, R, R, etc. They are of a type having two elements, one energized from the track circuit, and the other from the line wires j, 70. In the arrangement shown the armature elements of the relays are connected across the track rails, and their field elements are connected across the line conductors y', 70. The transformers are connected to the rails oppositely, that is to say, the positive terminal of the transformer C is connected to the same track rail as the negative terminal of the transformer C. The relays between each two transformers are connected to the line and across the track rails in such sense that the current from any transformer except the one intended to operate the relay, will be in the wrong direction to close its contacts, and will, therefore, tend to open its contacts. The arrows in the diagrams indicate the direction of the flow of current at any instant, and the figures preceded by the plus or minus signs indicate the potentials at the various points corresponding to the currents indicated by the arrows. These figures are, however, merely hypothetical, being used for the purpose of illustration only, and may have any values within reasonable limits. The secondary s of the transformer G will,

at a given instant, produce a potential plus 5, in the illustration given, at its connection with the rail r, tending to cause a current to flow in the direction indicated by the arrow; and it may be assumed that the impedance of the rail 1* is such that the fall of potential will be four volts between the point plus 5 and the point plus 1 at the extremity of the reinforced rail section 9. From the point plus 1 to the other extremity of the reinforced section g the potential falls two more volts to minus 1; thence through therail 1' there is a further drop of four volts to the terminal of the secondary s of the transformer C. In the other rail 1", the fall of potential is of equal amount, but in the reverse direction. This supposed case gives a difference of two volts of potential, tending to force current through each of the armatures a, a of the relays R, R. The fields f, f of the same relays are energized from the line conductors j, is, and in such direction that the currents therein coacting With the currents in the armatures derived from the track rails will cause the armatures to move and close the contacts 6, e. The end of each of the blocks is similarly equipped, and each signal is controlled by two relays, one at each end of the block, and supplied by current from a transformer between them and the two relays of each block having the contacts controlled thereby in series in the local or signal cont-rolling circuits.

WVhen a train stands on any part of the track section between a relay and the transformer supplying that relay, current is out off from the relay, and the signal circuit is opened, causing the signal to go to danger. The shunting of each relay will, of course, occur a short time before the train reaches that relay, even when it is not between the relay and its transformer; but by reason of the added impedance due to the iron placed alongside the rails, this distance can be very greatly tween a transformer and the relay, this relay will receive current from the next transformer beyond, but, as can easily be traced from the diagram, this current is in the wrong direction to cause a closing of the relay contacts, and will have a tendency to open the contacts. It will also be readily seen that the middle points of the reinforced rail sections will be at the potential zero. Two opposite zero points may, therefore, be joined by a solid conductor if desired without affecting the signaling current. It is desirable to join these points in this manner for the purpose of preventing as much as possible the unbalancing of the propulsion current. These connections are indicatedat m, m, m", in Fig. 2.

It will be seen that a of any block will always cause the short-circuiting of one of the two relays of this shortened. When a train stands betrain in any portion block, and that since these two relays have their contacts in series in the signal-controlling circuit, that circuit will be held open and the signal guarding the entrance to that block will remain at danger so long as the blockis occupied. In leaving any block, a train before losing control of the last relay of that block gains control of the first relay of the succeeding block, and thereby holds the signal behind the train at danger until such time as it is protected by the signal at the entrance to the next block. The manner in which relays are affected by the presence of a train will be clearly seen from Fig. 2. By reason of the increased impedance of the end portions of the track rails at the block limits, as herein described, the distances at which adjacent relays of two adjacent blocks will be shortcircuited by the train can be very closely determined, so that there will be but a comparatively small overlapping of the blocks. It will further appear that by the arrangement described it is impossible for any relay to be operated except by current from the transformer which is intended to operate it. The arrangement of the circuit is made very simple, but few line conductors being required since the invention permits the use of single-phase currents for the signaling circuits.

It will be obvious that many changes may be made in my invention. Thus, changes may be made'in the form of the plates or laminae, and in the manner of securing them in place; relays of any suitable type may be used for controlling the local signal circuits, and the manner of applying the signal currents to the track rails may be changed.

I claim 1. In a continuous rail block-signaling system, track rails having portions of increased impedance consisting of transverse plates or laminae of magnetic material at the sides of and underneath the rails; substantially as described.

2. In a continuous rail block-signaling system, a track rail having a laminated body of iron extending at the sides of and underneath the same at a portion substantially as described.

3. In a continuous rail block-signaling system, means for increasing the impedance of the track rails, consisting of laminae fitted between the head and base flanges of the rails, and also extending underneath the base flanges; substantially as described.

4. In a continuous rail block signaling system, means for increasing the impedance of the track rails, consisting of laminated iron plates fitted between the head and base flanges of the rails at one side thereof, and extending underneath the rail bases, and other plates or laminae at the opposite sides of the rails and secured to the plates or laminae which extend underneath the rail bases; substantially as described.

5. In a continuous rail block-signaling system, means for increasing the impedance of portions of the track rails, consisting of laminated iron plates placed at the sides of the rail and underneath the same, the plates at the outer sides of the rails being extended upwardly at the sides of the rail heads; substantially as described.

6. In a continuous rail block-signaling system, means for increasing the impedance of portions of the track rails, consisting of a body of laminated iron inclosing the web and base of the rail; substantially as described.

7. In a continuous rail block-signaling system, means for increasing the impedance of portions of the track rails, consisting of a body of laminated iron inclosing the web and base of the rail, and extending upwardly at one side of the head; substantially as described.

8. A signal system comprising a conductive track rail, and bodies of laminated magnetic material surrounding said rail with the exception of its head.

In testimony whereof, I have hereunto set my hand.

of its length;

JOHN D. TAYLOR.

Witnesses:

H. M. CoRwIN, GEO. H. PARMELEE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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