US2124629A - Railway track circuit apparatus - Google Patents

Description

July 26, 1938. B. E. O'HAGAN 2,124,529

- RAILWAY TRACK CIRCUIT'APPARATUS Filed oct. 30. 1957 Fig? 1.

Signal 28 Control 2 INVENTOR v j Benxardz O'Iizgan I HIS ATTORNEY Patented July 26, 1938 UNITED STATES PATENT owner.

The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application October 30,

' 15 Claims.

form of the apparatus of Fig. 1, also embodying my invention. A

Similar reference characters refer to similar parts in each of the two views.

Referring to Fig. 1 of the drawing, the reference characters I and 2 designate the track rails of a section of railway track defined by insulated'rail joints 3 at each end of the section. Connected across the rails at one end of the track section is asource of current 4, here shown as abattery, which supplies current to the track circuit over a current limiting resistor 5.

The reference character'R. designates a track relay comprising three parallel cores 6, I, and 8,.

two of which, 6 and 8, are connected at their upper ends by abackstrap 9." The remaining core 1 is spacedfrom the backstrap by an air gap Ill. The cores 6- and 8 are provided with operating windings I I and I2, respectively, which receive energy from the rails of the section over circuits which will be traced in detail herein-- after. Accordingly, two magneticcircuits are provided,-one of which includes core 6 and the other of which includes core 8, with the core 1 common to both magneticcircuits. The windings II and I2 are so disposed that the fluxes due to these windings aid one another in the common core I. Core 6 is equipped with a shortcircuited retarding winding I3, and core 8 is equipped with a similar winding l4, but the latter winding is normally an open circuit and becomes short-circuited only when the secondary relay S is released.

A tractive armature I5 is pivotally supported at bearing I6 for swinging movement toward and away from the cores 1 and 8, and a similar tractive armature I1 is similarly supported for movement with respect to cores 6 and I. The armatures I5 and H are biased by gravity to an open position away from the respective cores and carry contactfingers l8 and I9 which, in the closed armature position shown in the draw- 1937, Serial No. 171,928

ing, engage fixed contacts 20 and 2|, respectively.

The secondary relay S receives operating energy from a suitable source of current having the terminals BC, over the front contact I9- 2! of relay R. Relay S controls, over its back contact 2223, the short-circuiting of winding M, and over its back contacts 24-25 and 26-21, the closing of the pick-up circuit for relay R. Relay S is preferably designed to have a slightly 1 retarded pick-up so that a momentary closure of contact l9 2l will not cau'se relay S to pick up, thus avoiding undesired signal flashes due to opening of' contact 28-29 and closing of co'ntact 28-40,- which might otherwise result duri-ng a momentary loss of shunt.

Having described the various elements of Fig. 1 comprising the apparatus embodying my 'invention, I shall now describe the operation of this apparatus- When the track section is unoccupied, the apparatus will be in the condition in which it is illustrated in Fig. 1 of the drawing. That is, relay R will be maintained energized over a holding circuit which may be tracedfrom thelefthand terminal of battery 4', limiting resistor 5, rail 2, winding II, wire-3|, resistor 32, upper portion'of winding I2, wire 33, front contact I'8-20, wires 34' and 35, and rail I, to the righthand terminal of the battery. The secondary relay S 'will be maintained energized over front contact I92l of relay R, and so the appropriate signal circuit will be closed at front c'orltact 28 .38 of this relay. The pick-up circuit for relay R and the circuit for the retarding 35 winding I4 will both be open. The. purpose served by resistor 32 included in the holding circuit is to compensate either wholly or partly, as desired, for the resistance of those turns of Wind'- i-ng I2 which are excluded when the holding .circuit is effective.

, When a train enters the section, the shunt formed by the wheels and axles of the train will considerably reduce the current which traverses winding II and the upper portion of winding I2iin the holding circuit. Accordingly, the flux in cores 6 and 8 will rapidly decrease, but due to the presence of the short-circuited winding l3, the decrease of flux in the magnetic circuit of cores 6 and I will be less rapid than in the 50 corresponding magnetic circuit of cores 8 and I. There will, therefore, be present a magnetomotive force due to the magnetic circuit of cores 6 and I whichwill oppose the flux in the magnetic circuit of cores 8 and I, which magnetomotive V net to a lower value than would occur merely combination.

by virtue of the decrease in current of winding l2. magnet will release at a higher value of train shunt resistance than it would without the opposing effect of theflux in the right-hand magnet, and will thus provide a higher degree of shunting sensitivityv than is provided in the usual and well-known primary-secondary relay It will be apparent that Winding l3 has a discriminating effect between a slow decrease in energization'of relay R such as occurs when the ballast resistance decreases, and a relatively rapid decrease, in energization such as occurs when a train enters the section. Accordingly, winding I3 is effective in improving the shunting sensitivity of relay R:by raising the release value of armature I5 and inaccelerating the release of this armature only under the train shunt condition, this winding being normally inactive'during changes'in ballast resistance.

As soon as armature l5 releases, front contact l8-2l) will open and will interrupt the circuit for both windings II and I2, whereupon armature ll of the right-hand magnet will quickly release. The release of armature I! will open the circuit a for relay S at contact the retarding winding 14 aswell as the pick-up circuitfor relay R. The'pick-up circuit may be traced from rail 2, winding ii, wire 35, back contact 26-21 of relay S, wire 31, full winding l2,

wires 33 and 38, back contact 2 4251of relay 8;. and Wire 35, to rail l.

Preferably, the windings ii and I2 will each have the ,same number of turns so that the right-hand and left-hand magnets may be similarly or interchangeably designed. If desired, the windings 7H" and I2 may be replaced by a single winding positionedon the common core 7 and supplying the necessary fiuX to the two magnetic circuits. By suitably tapping the single winding, aholding circuit of a decreased number of turns, similar to'that for the pair of windings II and I2 may be obtained. w e

The reason for equipping core 8 with a retarding winding [4 which is similar to winding IS on core 6 is to provide similar conditions during pickup for both magnets so that at this time both cores 6 and 8 will havethe same number of short-circuited turns as well as the same number of operating turns. Accordingly, when a train leaves the section, both armatures i5 and I1 will become attracted at about the same time, although this'condition is not essential from the standpoint of operativeness. That is, winding I 4. may be dispensed with, if desired, provided the apparatus is so proportioned that a prior pickup of one armature IE or I! will not prevent the other armature from picking up.

Under certain conditions; as Will'be explained more fully in connection withFig. 2, it may be advantageous to eliminate winding [4 in order that armature l5 will be first to pick up, thus delaying the'pickup ofarmature I1 and introducing a corresponding delay in the pickup of relay S.

When the section becomes unoccupied, relay R will pick up and the closing of contact I820 will reestablish the holding circuit previously cause relay S to pick upwhich will, in turn, open the pick-up circuit for relay. R and the circuit for winding I4, thereby restoring the sensitive As a result, armature [5 of the left-hand 3960 alone. l92l, releasing this relay and closing 'vantage of this arrangement is that a quicker release of relay S will be obtained by virtue of w the fact that armature I5 is first to .releas'e,-so that the signals will respond more quickly to V the entry'of a train into the section.

In thisfigure, the circuit for relay S mayor may not be carried over the contact I9-2I of the'right-hand magnet, as desired. If relay S is a standard relay which does not have slow pickup characteristics and if the retarding coil 14 is not used, then it may be desirable to include both contacts 39-4!!! and l92l in the circuit. for relay S, so as to time-delay the pickup of the relay. In this manner, an operation equivalent to that of Fig. 1 with an inherently slow. pick-up relay S may be obtained. By usinga 1 a slow pick-up relay, however, the contact 9-2l may be completely eliminated, the pick-upcircuit for relay S being A further difference between Figs. 1 and 2 is that in the latter figure the wiring for the pickup and holding circuits is slightly rearranged so as to eliminate the extracontact 2425 of relay S. In all other respects, however, the pickup and holding circuits for relay R are the same as in Fig. 1, and will be obvious from the drawing without further explanation.

It will be apparent that" the improvement in shunting sensitivity of relay R which I obtain then carried over contact is .due to two factors, namely,'a higher release.

of armature l5 by virtue of the opposing magnetomotive force resulting from the unbalance between the right-hand and left-hand magnets at the time the track is shunted, and a higher release of this armature due to the decreased ampere-turn magnetization of the relay when the holding circuit is effective. However, in-

order to realize the advantages of myinvention it is not essential that the normal energizing circuit for relay R include a resistor and exclude a portion of the operating winding, or thatthe holding ampere-turns be decreased, so that the secondary relay S may be dispensed with entirely, if desired. That is, the full turns of both windings I l and I2 may be used not only at pickup, but also during the normal holding operation of the relay. One manner in which the effect of fewer holding ampere-turnsmay be obtained hand magnets will also be unequal, the flux in the right-hand magnet being the greater of the two, so that armature I5 will have its release point substantially raised. By properly adjusting this flux diiference, armature l5 may be brought as close to the release point whena given shunt is applied to the track, as though a holding circuit of decreased ampere-turns were used.

Although I have herein shown and described only two forms-of railwaytrack circuit apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from thespiri't and scope of my invention. 1 I

Having thus described my invention, what I claim is:

1. In combination with a section of railway track and a source of current connected across the'rails of said section, a primary relay having a first and a second magnetic circuit each including a common magnetic path, means associated with said first magnetic circuit for retarding the flux decay therein when said track section becomes shunted to thereby accelerate the flux decay in said second magnetic circuit, a secondary relay, an energizing circuit for said secondary relay including a contact of said primary relay, a

pick-up circuit for said primary relay connected. across the rails of said section and including a contact of said secondary relay as well as the full operating winding of said primary relay, and a holding circuit for said primary relay controlled by a contact governed by said second magnetic circuit and including only a portion of the operating winding of said'primary relay.

2. In combination with a section of railway track and a source of current connected across the rails of said section, a primary relay having a first and a second magnetic circuit each including a common magnetic path, means associated with said first magnetic circuit for retarding the flux decay therein when said track section becomes shunted to thereby accelerate the flux decay in said second magnetic circuit, a secondary relay, an energizing circuit for said secondary relay including a contact of said primary relay, a pick-up circuit for said primary relay connected across the rails of said section and including a contact of said secondary relay as well as the full operating winding of said primary relay, a resistor, and a holding circuit for said primary relay controlled by a contact governed by said second magnetic ,3 circuit and'including only a portion of the operating winding of said primary relay and said resistor.

3. A track relay for improving the shunting sensitivity of a track circuit comprising, in combination, two magnetic circuits for said track relay each including a common magnetic path and each adapted to be energized from the track, a control armature for said track relay associated with one of said magnetic circuits, and means associated with the other of said magnetic circuits and discriminating between a relatively slow decrease in energization of the track relay such as occurs due to a decrease in ballast resistance and a relatively rapid decrease in energization of the track relay such as occurs due to a train shunt for accelerating the release of said armature when said track relay becomes shunted.

4. A track relay for improving the shunting sensitivity of a track circuit comprising, in combination, two magnetic circuits for said track relay each including a common magnetic path and each adapted to be energized from the track, a control armature for said track relay associated with one of said magnetic circuits, and means associated with the other of said magnetic circuits for retarding the fiux decay therein when the track becomes shunted to thereby accelerate the flux decay in said one magnetic circuit and so to accelerate the release of said armature.

5. A track relay for improving the shunting sensitivity of a track circuit comprising, in com bination, two magnetic circuits for said track relay each including a common magnetic path and each adapted to be energized from the track, a control armature for said track relay associated with one of said magnetic. circuits, a shortcircuited winding associated with the other of said magnetic circuits for retarding the flux'decay therein when the track becomes shunted to thereby accelerate the fiux decay in said one magnetic circuit and so to accelerate the release of said armature.

6. A track relay for improving the shunting sensitivity of a track circuit comprising in combination, a first and a secondmagnetic circuit for said track relay each including a common magnetic path and each adapted to be energized from the track, a first and second armature associated respectively with said first and second magnetic when the track becomes shunted'to accelerate the flux decayin said second magnetic circuit and so to release said secondarmature before said first armaturereleases, and signaling apparatus controlled by a said two armatures.

'7. In combination with a section of railway track and a source of current connected across ciated with the other of said magnetic circuits. v

. 8. In combination with a section of railway track and asource of current connected across the rails of said section, a track relay having two' magnetic circuits each including a common magnetic path, a circuit including the rails of said section for energizing said two magntic circuits, an armature associated with one of said magnetic circuits, and means associated with the other of said magnetic circuits effective when said track section becomes shunted by a train for accelerating the release of said armature.

9. In combination with a section of railway track and a source of current connected across the rails of said section, a track relay having two magnetic circuits each including a common magnetic path, a circuit including the rails of said section for energizing said two magnetic circuits, an armature associated with one of said magnetic circuits, and a short-circuited winding associated with the other of said magnetic circuits effective when said track section becomes shunted by a train for retarding the flux decay in said other magnetic circuit so as to accelerate the flux decay in said one magnetic circuit and expedite netic path, a circuit including the rails of said trolled by said armature for improving the. shunting sensitivity of said track relay.

11. In combination with a section of railway track and a source of current connected across therails of said section, a track relay havingtwo magnetic circuits each including a common magsection forenergizing said two magnetic circuits, an armature associated with each of said magnetic circuits, means associated with one of said magnetic circuits effectivewhen the track section becomes shunted by a train for acceleratingthe release of the armature associated ,Withthe other of said magnetic circuits, and means controlled by both said armatures for improving the shunting sensitivity of said track relay.

12. In combination with a section of'railway track and a source of current connected across the rails of said section, a track relay having a first and a second magnetic circuit each including a common magnetic. path, a circuit including the ;rails of said section for energizing said first and said second magnetic'icircuits, afirst and a second armature associated respectively with said first and said second magnetic circuits, means associated with said'second magnetic circuit for accelerating the release of said firstarmature upon shunting of said track section, an auxiliary relay 7 controlled by said first armature, and means controlled by said auxiliary relay and effective when the shunt is removed from said track section for equalizing the pick-up time for said first and second armatures. v I g 13. In ccmbinationwith a section of railway track and a source of current connected across the rails of said section, a track relay having two magnetic circuits each including a common mag- I relay.

netic path, means receiving energy from the rails r of said section-for setting up, aiding fluxes in said two magnetic-circuits, an armature associated Withone of said magnetic circuits, and

means associated with the other of said magnetic.

circuits effective upon a rapid decrease of the energy received from said rails when, a trainenters said section for aiding the release oflsaid armature. t i

14. A track relay for railway signaling track circuits comprising, in combination, twomagnetic circuits for'said trackrelay eachincluding a common magnetic path, means for setting up aiding fluxes in said two magnetic circuits,'and means associated with one of said magneticfcircuits effective upon a relatively rapid decrease of two magnetic circuits, an armature associated with one of' said vmagnetic circuits, and means associated 'withthe other of 'said magnetic cir-. cuits and discriminating between a rapid decrease in the energy received from said rails such as occurs when a trainenters the section and a slow decrease in saidenergy due to a decrease in bal last resistance for modifying the release value of said armature.

BERNARD E. OHAGAN.

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