US1890419A - Automatic train control - Google Patents

Description

Dec. 6,-1932. D. H. SCHWEYER 1,890,419

I AUTOMATIC TRAIN CONTROL Filed Nov. 10, 1931 Patented Dec, 6, 1932 v My invention relates to improvements in mmssmT-ES ANI L' ERBER soHwEYEn, 'or 'nns'ron, EmI's VANIA AUTOMATIC TRAIN ooivrnon Application file d liovember '10; 1931. Serial N0.1574,188.1

automatic train control and has to do, more particularly, withtrain-carried receivers and the trackway means by which conditions are transmittedtheretog, v f r Several serious problems have been found toexist in connection with inductive receivers in present use. Because rails are made of steel, trackway armatures must be spaced from the rails a considerable distance,-and in order that a minimum amount of interfer ference be had from crossovers and switches, it has been found preferable to dispose the trackway armature outside of, and parallel to the track; ;The mostcommon systems of inductive train, control now in use operate either upon the principle of inducing current in relay energizing coils gcarried by the train, or upon the principle of choking the'winding 0 upon an open core on the train byibridging the core gap with'a trackway armature having an 'open-circuited winding.v In, order that such systems operate properly, extremely accurate adjustments, and highly sensitive electro-responsive control and indicating devices must be employed. In such systems theindicative current variations generated, or

suppressed are often extremely smalland, vary greatly in accordance with the speedof vthe train at the time of passage over the trackway element so that, adjustments, at

best, can be made only with "average train speed as theirbasis. A train, thusequipped,

movingover a tralckway armature at extreme.- ly low speed, sayiive mles per hour, might pass into a danger block vwithout IGCBIYIIIg any indication whatever-of such condition.

And an automatic safety device which isnot 100% operativeunder every possible ,conditionis not only ineiiicient,fbut, because of ithe reliance naturally placed thereon, is a'menace. worse than no safety device at,

to safety and all. I i

With these and other factors injmind, my

invention has for its purpose the accomplishment of several well defined obj ects. 1 p

The primary object ofmy invention is to provide-a traincontrol system which is more sensitive than. systems heretofore in use,

. Another object of my. invention is to pro,- v

9 I A'furtherobject-ofImyinventionisito proof a preferred form of my invention as em ing three poles adapted. Iran coaction "with vide a traincontrol system which will operate'uniformly and accurately regardless of whether the train be travelingat high, mod-- erate, or extremely lowspeed. v a i vide a'train-carrijed receiver which is simple inconstruction,positive inaction, unlikely require frequent adjustment','inexpensive to manufacture, andi lowi 1n current-consump Further eration will definitely appear fromi the "def tailed description to follow,- In onefinstanc'e I accomplish the objects-of my'linvention byi .the devicesand means set fprthvin'thejfollgwg ing specification. 1 'My invention is clearly gdefined] and pointed out in the appended claims; Structures constituting preferred embodiments of 'my'invention ar i1 1 tmt 7o i in the accomp nying drawing forming apart of this specification, inwhich: i

Figure l -is a diagrammatic representation bodiedin apparatus including a three-pole 11 train-carriedreceiver core and atwo-poleflux-shunting trackway armature; Fig.2 'sa diagrammatic representation of analternate form of trackway armature havthe three pole pieces.*0ftrain carried equipment such as shown in Fig; ,1; i r V Fig.3 is a'diagrammaticrepresentation of a modified form ofmy invention as embodied in afour-pole H type :receiver' core; a; a

,FigAisa diagrammat-ic'representationsof i a modifiedform of my-inventionas adapted for operation with aTsingle A. 'C. source, and 7 showing a modified form trackway means; and I 90' Fig; 5'is a diagrammatic representation of I still" another modification of my invention in Wl'llChf-h receiver core is normally magnet ized byvDQC. and the control or indicating;

latediby the trackway armature. I In the drawing the same reference numerals refer to the'same or similar parts throughout the several'viewsn' r P v v; objects and objects relatingto details and'economiesj of construction and op-f 1 of flux shunting device is energized only upon the occurrence of -.a changed trackway conditlonas trans i V Referring now to the numbered parts ofmy drawing,'and more particularly to Fig. 1 thereof, there is diagrammatically illustrated a train-carried receivercompris'ng a threeleggedsyoke or core 10, onthe outer legs 11, and 13 of which are disposed coils l4 and 15' vwhichare so wound and connected to the A.

-C. 'source16'as to 'j'ointiyset u'p" flux in the core 10. The middle leg 12" is at the flux centerof the: core and therefore is'substantially free froin fiux setup by coils 14 and 15. I An impulse coil 17 is 'dsposed: around; leg'12 and a low power D. C. source 18' and 1 a holding relay 19 are connected in. series with coil 17. Associated with relay 19 and held'closed so long as the relay circuitfre mains uninterrupted, is an indicator orcon trol c1rcu1tjco'mpr1singa relay controlled;

switch arm 20, a source of cur'rent'21, "and a signal device or electro-energized'.brake control 22. A trackway-mount-ed' element for influencing. the train-carried receiver in accordancewithtrackway conditions comd prises a core 23 having'upstanding' arms its ends, a choke winding 24 intermediate its ends, andia relay'ors-witch 25 for opening 3 r or closing vthe' choke winding infaccordance with trackway conditions; The circuits for operating relay25 may be conventional and I "are therefore not illustrated.

'. The operation a of the"apparatus shown in Fig. '1 is as follows, Alternat ng current generated by theA. C; source, 16 energizes coils 14 and 15, j'settingu'p a flux in core :10 as though it were of simple U'f rmQ-that' is, middle leg 12 issubStantiaIlyfreeifrom A. C. flux. Impulse winding-1'1 on leg 12 therefore normally has no [current induced [therein and under such circumstances serves merely to complete the'circu t connecting the .weak D. C. source 18' to the relay 19 which an open circuitedwinding 2'4, the-tra'n-car-c Fried receiver will beunafi'ectedp However,

when the train-carriedfreceiver' passesove'r a trackway core 23 having a winding 24 which isn'otclosed bythe switch 25, that is .to say, overa trackway armatureactuated toiind catea caution or danger condition,

fstrong A, C. flux isishunted through the trackway core 23 and the middleleg'12superposing and neutralizingthe weak fiux set up in the leg. 12 bythe weak D. C; source 18,

I and by. transformer action tendingto setup l (it) most, acoinplete cycle of alternating current an alternating current in impulse winding 17. v.HoWever, superposition of" one-half, oi at in w nding 17 will prov'i'dea momentary ces sationof current flow throughthe winding of relay 19 and allow relay'arm 19a and sw tch arm to drop, properly cutting on,

source of current 21 from-the indicator or" indication or the application of brakes.

control device 22-and providing a w r i '3 i V In Fig. 2 there is shown a three-armed trackway element having two choke wind-j I lngs which may be used in'place oi. the twoarmed trackway element shown in Fig. 1. In 7 this embodiment there is a three-armed core I26v having outer arms 27 and 29 and a middle arm 28. A pair of choke windings 30, 31, on the body of the core 26, are controllable singly, or in multiple, by the relay32 which is, in turn, controlled by a conventional track-,

way block indicating circuit.

'In Fig.3 there is showna somewhat modified form of train-carried receiver embodying my invention whichcomprises a core 33.

of;H 'form, upon the central bar 34 of which i's wound-a coil 35 which is' energized by a comparatively strong D.]G. source 36; no

Pair of Opposed rms 37, 38, extend downwardly from thecentra bar 34 of'theio fe" and terminate'in feet 37a and 38a,which are, 7

rather widely spaced from each other pro- H I viding an air gap A and thus constituting; with central bar 34, "a flux circuit of rather:

high reluctance. A- second pair'of arms39,

40,,branch from the'end's ofthe middle bar 34 and terminate-opposing" each' other across'an -air gap B of less width than gap A and'constitute,with central bar 34, a flux circuit of lower reluctance than the aforementioned flux circuit including airl gap I Impulse coils 41,42 are connected in series in a relay circuitwhich includes a holding relay 43-and J a" comparatively wea,k=D.; C. source 44.

. D. C. source 44-is so connected in the-relay circuit that the flow of current, which would bemoinentarily in'ducedin' coils 41, 42'upon connection of D. Gtsource 36 to coil 35, would i augment said D. C. source44. Thus, and in versely, disconnection :of the strong" D; C.

source 36 from-coil35 would result in a current kick momentarily overcoming the weak current made to flow'in the relay circuit by I 3 Weak DLIG. source44.

The operation of th'e apparatus shown in" Fig. 3 is as follows- So longras the train and i its receiver does not pass over the- 'trackway element havlng an open w1nd1ng,D'. G.source '36 will energize coil .35, setting upfiux in the flux circuit comprising central bar 34,- arms 39yand4O and air gap B. Little or no flux will be set, up in the circuit including arms-37,

"38'and air-gap A, because of its'greater reluctance; Once the D; C. source 36 has been connected tocoil 35, no current will "be ,in-

duced in coils 41, 42, and the weak D. C.

source '44will" maintain relay (43 stuck and theindicator orcontrolcircuit energized so long as clear trackw'ay cond tions continue to BX7S11. However, upon the passage-of the feetq37a,38a of-thereceivercore 33 over a trackway core 23, having a choke winding 24 open-c'ircuite'd by a relay 25, core fluxsetup by coil is immediately shunted through the clrcuitwhich includes legs 37, 38 and gap A bridged by core 23. The flux circuit including legs 39, 40, is thus instantly robbed and a current kick is set up in coils 41,42, which is stronger than, opposed to, and overcomes the normal currentflow effected by D. C. source 44. Relay 43 allows the arms43a and 20 to fall, thereby appropriately. indicating" the danger condition or setting the train- .brakes.

. In Fig. '4 there is shown a similar type of receiver'adapted for energization and operation with a'single A." (l-source, As in the form shown in Fig. 3, there is an H type receiver core 33, having twopairs of opposed " arms 37,38 and 39, 40, the air gap 39 and and are connected in series to enera gifze A. C. holding relay 53 with current induced in'coils 51, 52.- A somewhat modi fied trackway armatureisshown in Fig.4, which armature comprises astralght bar'or core 123 having no'legs and wound for sub- Q stantially'its entireextent with a choke winding or coil 124. The conventional relay 25 controls the opening and closing of the choke winding as in the other trackway elements shown. One advantage of the form of track'- way armature shown'in Fig. 4 is that there is a minimum offlux leakage around the winding 124. f

The operation of the apparatus illustrated in'Fig. 4 is as follows. A.C. source.56 constantly energizes coil 55, setting up flux in the central bar 34 of the core which flux normally passes through the flux-circuit including arms 39, 40, and air gap B. Alternating current i's thus induced in coils 51, 52 on I arms 39,40 and such current maintainsholding relay53 energized :to hold relay arms 53a and 20closed and thus properly control indi eating orbrake' setting device 22. However,

under danger conditions, relay 25iopensthe choke winding 124 of the-trackway armature causingcore 123 to constitute a flux bridge for the air gap A. The flux circuit includ:

ing arms 37, 38 and air gap Atherebv becomes of lower reluctance than the c1rcu1t including arms 39,40 and air gap 13. Flux is thus shunted from the coils 51, 52, and little or no current is induced therein with the result that relay arms 53a'and20 fall and the danger indication is given, or the brakes are set, or both, depending upon the nature and construction of'the element 22, which may take many forms. j i i f In 5 there ,1s "shown a somewhat modified form of receiver embodying mv-invention and adapted for operation with a single D. C. source. Q As in the form show-n in Figs. 3 and4, there is an Htype-receiver core 33 having two pairs o f op'posed arms 37, a l

38 and 39,40, the air gap Act which is wider than the air gap B. Afcoili disposed upon the central bar34 of the core'and is energized by all C. source-64, magnetizing eludes arms 40 and airgap B. Impulse coils-61, 62 disposed onarms'39 and 4Qpare connected in series tothe magnetic relay 63 having a normally closed relay c1rcu1t arm the core circuit of lower reluctance which in- 1 63a and a' control or' indicator circuit arm 120 which is'closed in the absence of current flowin the relay circuit and maintains "the indicator or co'ntr'ol'currentsource 21100111,

Fig. @5'LlS as follo'ws. So long as the train does not'pass over atrackway armature core= nected to the'indicator or control device 22.] Theoperation of the receiver shown in 23'having a choke winding 24 whichisopen' circuited, as by the relay 25, the arms 39, 4'0 y will remain magnetized by D. C. flux set up by coil Should, however, the train pass 0 over an open circuit'ed windingfl24 andits core 23,-the arms 39, 40 rwillbe totally, or at least largely demagnetiz'edby reason of 1' shuntingofthe flux into'thefci'rcu-it including a-rmsj37,38 and core 23. ,A current kick" V will thus be'generated'in coils 61,62 and the electromagnet of the relay 63 willmomenw tarily lift the arm'120,'*breaking oil the current source 21 fromthe indicator or control device 22.

In equipment of'jthe character above described, where the current which efiects change in theelectroresponsive indicating or control. device 1s provided byinduction in a secondary coil through which" flux passes. only wh'enfthe receiver core is'bridged by the trackwayelement, it is vital that such.

bridging exist for a space of time sufi'icient to cause a substantial current to be I In the form of track'way' elementshown inFigZ" 4, adequate bridging Ia's'sured; even induced in ,the secondary coil.

at ..exceptionally high speeds vand coil'55. due tothe elongateform ofthe'core 123. The same istrue of the formcftrack way element shown inFig. 2. By way of .with allowfrequency current source for the illustration, should thereceiver shown in Fig. 1 be used with a very low frequency current form there shown, and should thertrain be .16 and a very small trackway element of the traveling at a very high speed it might happen that the legs 11-, 12 of the core 10 would completely-pass over the core-23 -during-the' moment when the. sine wave ofthe alternat-. ing current flowing incoils 14 and :15 was at its crest. In that eventthe currentinduced' incoil 17 would be negligible and ins'ufiicient to effect dee'nergiza'tion *or 1 the electro-responsiive devicel9. Usingthe form of track- 7 wayelement shown in Fig; -2, -=it wouidbe sud re cl impossible for the receiver coreQlOlto clear thei'core 26dur1ngjthe moment thecurrent. wave Wasat 'lllS crest.

q 1 'lVhile Ihave disclosed what, I regard tobe preferred embodiments of my invention, such are illustrated primarily forthe purpose ofexplaining the inventiomand are by no means to lie-regarded as the only forms in which it is capable of embodiment. Numerous variations will appeal to those skilled inthe.

who become familiarwiththe concepts ot thepresent invention. For example, while 1 have disclosed choke-wound trackway element which effects br dging or shunting of a flux path of high reluctance by reason of open circuiting its winding, it is obviousthat such br dging -might be accomplishedbyan unwoundbar of magnetic material and might be controlled by posit-ioning'the barwith respect to the line of the receiver core. While I have shown electromagnetic relay elements '25, 32 for operating thechoke circuitrswitches, it is to be undei'stood that other equ'ivar 'lent means,'manual, or mechanical night be used. While Ihave'found it preferable, in

order to avoid interference by cross-oversand I switches to so mount the tra'ckway receiver core uponthe train thatiit hangssome ten or twelve inches outside of the rail and cooperates with a tr'ackwayi-elen'ient disposed] approximately two andone-lialfinches above the rail, under certain conditionsfltmight be desirable to dispose the receiver core and trackway armatures transversely of the traokway. Similarly, while I have varied the reluctance of the several flux circuits of the core by making air gaps therein of different widths, other methods such as-usingdifiier- ,"ent corematerials, difi erent core cross, sec

tion or auxiliary'choking means might be substituted' Further, while Ihave referred to the control current as alternating in character it is to be understood thatthisterm is intended to include any suitable-fluctuating current. andis not restricted to" any specific, frequency,

since theiapparatus will operate on frequen- I cies lower than ;cycles per second or higher eventhan- 360 cycles per second. Likewise, while I b ave shown in Fig. 1, a pair of coi s connected in parallel to theA. C;- sourc'e,.it is obvious that suchcoils, wound to diifer'entially polarize the core, may be connected in series if desired. If-desired, additional coils may be placed upon the legs 11 and 23 of the I device'shown in Fig. 1, so as to operate as a "two-phase or three-phase system. -,Mo reove r,

7 -;.for the purpose of positively opening the re- I lay in the secondary circuit of the form of apparatus shown in Fig. lyFigQ 3 or Fig." 4,

should the primary; current source fail, a

v safety relay maybe incorporated consisting of an electro-m'agnetic element in :the pri- 5 'Inary circuit and a switch arm actuated thereby which controls continuity of the secondary v those skilled in the art;

circuit. Numerous other variations within.

the scope .of this invention will appeal to 'It-isto be understoodtthat while the present invention is disclosed as embodied in a simple train control system indicatingonly clear or danger conditions, iits concept is readily capable of embodiment in'counting "pr translating train control systeins and even in apparatus; for performing other. functlons,

for example, exploring systems for indicating the presence of hidden magnetic bodies. I 1 Lthereforeyclaim my invention broadly as indicatedby th'e appended claims.

WhatI'claimiszi' ,2 1. In a train control'system, atrain-carried' receiver including 'a magnetic core, a

constant. current source, winding on said core' I energized by said constant currentfsourceand settlng up normal flux'd1'str1but1on-1nsa1d core, an electric-responsive control, orindieating device, a second winding. on said core,v

saidsecond windingbeingso arranged with 1 respect to the normal distribution of flux in said core and so electrically associatedwith said electrosresponsive jdevicethat saidi des vice remains undisturbed during andonly dur ng the existencejof. sald normal flux} distribution in" said vcore and altrackwaywith respect to said receivercbut'rendered effective in accordance with-adversetrack:-'

way conditions-to. shunt away ala-rge portion of the. flux normally existent in one coil on eachof the-outerlegs of said yoke.

energized bysaid A. C. source,'said coils beingso wound with respect to each other thatthe middle leg of the yoke isnormally neutral or free from-fluxrs'et up by. said coils, I

an impulse coil onfsaid [middle leg, an electro responsive control or indicating device,

and a source of current weaklyfenergizing said device and lmpulse c011,.sa1dv last mentioned current source being out offphase' with.

said'first mentioned A; C. source and a track,-

way-mounted armature ofmagnetic material normallynon-influentialwith respect to said rece ver. but rendered effective 1n accordance with adverse trackway condltlonsj to mag.-

. netically bridge the space between the middle g leg and an outer leg ofthe yoke thereby di-fvertingyoke flux generated byjthe' coilojn',

that outer leg through said middle leg causing current to' be induced in said impulse coil which is out. of phase with andiovercomes the current normally energizing. said electro-responsive control or -indicating de vice.

mounted. armature normally-non-influential 9" 3. In a train control system,.,a train-carried receiver comprising a three-legged yoke of magnetic material, a source of A. (l,- a coil on each of the outer legs of said yoke energized by said A. C. source, said coils being so wound with respect to each other that the middle legof the yoke is normally neutral or free from flux set up by said coils, animpulse coil on said middle leg, an electroresponsive control or indicating device and a source: of D, C. weakly energizingsaid' device and impulse coil; and a'trackway-- mounted armature of magnetic material nor;

mally non-influential with respect to said receiver but rendered efiective in accordance with adverse trackway conditions to mag-j netically bridge thespace between the middle. leg and an outer leg of the yoke thereby di verting yoke flux generated by the COiI on that outer leg, through said middle leg in ducing A. C. in said impulse coil which overcomes the D. 0.. normally energizing said eleetro-responsive control or indicating device. 4. In a train control system, a train-carried receiver comprising a three-legged yoke of magnetic material, a source of A. G., a,

coil on each of-the outer legs ofsaid yoke] and connected in parallel to said A. C. source,

said coils being so wound with respect to each other that the middle leg of the yoke is normally neutral or free from flux set up by said coils, an impulse coil on said middle leg, anv

electro-responsive control orindicating device, and a source of current weakly energizing said device and impulse coil, said last mentioned current source being out of phase .with said first mentioned A. C. source; and

a trackway-mounted armature of magnetic material normally non-influential with respect to said receiver but rendered effective.

in accordance with adverse trackway conditions to n'agn'etically bridge the space between the middle leg and an outer leg of the yoke thereby diverting yoke flux gener-, ated by the coil on that outer leg through said middle leg causing current to be induced in: said impulse coil which is outof phase with and overcomes the current normally energizing said electro-responsive control or indicating device. v I i I 5. Ina train control system, a train-carried receiver comprising a three-legged yoke of magnetic material, a source 0 connected in parallel to' saidA. C. source,

said coils being so wound with respectto each other that the middle leg of the yoke is nor; mally neutral or free from flux set up by said coils, an impulse coil on said middle leg,'ai1

electro-responsive control or indicating device, and a source of D, C. weakly energizing said device and impulse coil, said impulse 00.1 F device, and D. C. source being connected in. "series; and a trackway-rnountedarmature of 0., a coil on each oi theouter legs of said yoke and,

magnetic material normallynon-influential. with respe'ctto said receiverbutrendered efor v I .fective in'accordance with adverse trackw ay conditions to magnetically bridgethe space between the middle-leg and an outer leg of the 'yokethereby diverting yoke flux-generated by the coil on that outer leg. through said middle leg, inducing A. G. in said impulse i J coil which overcomes the. D. C. normally energizing said electro-responsive. control or indicatingdev ce i 6. In a traincontrol system, atrain-carried connected inparallel to "said .A,

each otherthan the middle ,leg'of the yoke is normallyneutral or free, from; flux set up by said coils, ani npulse coil on said middle leg, an jelectro-responsive control or, indicating device, and a source of D. C. 'weaklye iergizing said device and impulseicoik-said impulse coil, device, and D. C. source being. con--.

nected in series; and attrackway condition transmitting element comprising a core of magnetic material of such length and so disposed with respect to the plane of the receiver yoke as to constitute a flux bridge diverting yoke flux generated byanouter leg coilthrough the middleleg of the yoke in d'ucing A. C. in said impulse coil powerful, enough :to overcome the D, C. normally energizing said electro-responsive control or in- Cl1Cit1I1gd8V1CQ,aI1d a choke winding on the core of said trackway element which when receiver comprising 'a three-legged yoke of 'magnetic material, a sourceof A; 0. a coil. on each of the outer legs of said joke and V source, said coils being so wound with respect to; 7

closed renders said core inoperative asa flux bridge forsaid yoke. i

7. In a train control system, a train-carried receiver comprising a constant currentsource,

a coil connected-to said current source, a core of magnetic material having a trunk portion disposed through said coil and energized therebyandbranches at the ends of said trunk j portion ,which branches define two distinct circuitsfor the flux set up in saidcore, one. of said circuits having less reluctance than the other circuit andnormally' constituting thepreferred an m P for the flux? an electro-responsive control or indicating device, and an impulse coil wound around the normally preferred flux circuit, said last mentioned coil being so electrically associated with said electroresponsivedevice that said device remainsundisturbed during and only during the presenceof'iiormal flux in said preferred circuit; and a. trackway-Y mountedv armature normally non-influential 8011 which was appidpi iia actuation; f the "elec'tro responsive "control or indicating device.

8. Ina train control system, a train-carried receiver comprising a magnetic 1" core of Hforin, one pair of opposed arms ofwhi ch; 1 are more widely spaced than the other pair,

a" coil on the middle bar'vof said core, a constant current source energizing said -j coil, an 'electro-responsivecontrol or indicating device, and coils' on the pair of opposed core arms which are less widely spaced, said 1 arm a-trackway-mounted armature normally noninfiuential with respect to said-receiver but "rendered effective in accordance with adverse'tr'ackway con'ditions'to constitute a flux bridge across the more widely spaced pair of opposedcore arms, th'us robbing thGCOllS [on the other pairof opposed arms of the flux normally existent therein.

, 7 9; In atrain control system, a

train carried receiver comprising a inagnetic core of H 'form, one pair of opposed armsflof which-are more widely spaced than the other {pa1r, a

' coil on the middle bar of said core, a constant currentsource connected to and energizing said coil, an electro-responsiv'econtrol "or 1111 dioating device, coils onthe pair 'of core arms which arefless widelyfspaced, and; a source ofDQ, C. .weakly energizing'said' coils and electro responsive device; and a" trackway mounted armature normally non-influential with respect 1 to said receiver but ren'dered' 7 effective inaccordance with adverse trackway conditions to constitute a fluxibridge across theimore widely spaced pair of opposed core arms, thusrobbing the coils" onthe less widely spaced pair of'opposed armsof the flux normally existent therein and causing a: current kick in said coils which opposes the D. C. energizing the electro-responsive device: V i

10. In a train control system, a traincarried receiver comprising a magnetic' core control or indicating; device, a second, and

i of H-form, onepair ofopposedarms of which 7 are morei-widely spaced than the other pair,

a coil on the middle bar of said core, a main source of D; connected to saidco l and polarizing said core, an electro-resp'onslve comparatively weak source of D.CQ, and coils on'said less widely spaced pair of. opposed,

V tinct circuits forthe flux setup in said'core,

7 "core arms which areso connectedin' .a series 'circuitw th said dev ceand said weak D; C.

source that the flux setiup. in said less; widely spaced arms by said main D; C; source is augmented bythe flux therein setup by said .weak'D. C. source; and a trackway-mounted' armature-F normally non-influentialwith rea H spect tosaid receiver but rendered effective in accordance with adverse trackway'condi tions to" constitute a flux I bridge across the more widely spaced pair ofiopposed core" arms, thereby robbing the less widely spacedv arms of flux and generating in the coils dis-, 76 7 posed thereon a current kick which opposes and overcomes the D. G. provided bysaid' weak D. C. sourceofenergizing said electro responsive control or indicatingdevice. v '11. Ina train control system,fa 13111111 carried receiver comprising a magnetic'core of H-form,=one pair of arms of which are" more widely spaced than the other pair, a coil 1 on the middle bar of said core, a 'sourceof V A. C. connected to'and energizing sa1d'-co1l,-

"an A.'C. li'oldingrelay governing a control of indicating circuit, relayener'gizingcoils on arms in which'clirrent is normally generated by-A. .C. fluxfin said lesswidely spaced arms set. upby, the coil on said middle bar; and a said lesswid'ely spaced pair of opposed core" trackway moun'ted armaturefnormally non influential with respect to said receiver but.

renderedeflectivec-inaccordance with adverse o traekway conditions to constitute a flux bridge across the more widely'spacedpair of opposed core arms; thus shunting andare more widely spa ced than thefl'otherpaina coil on the middlebar of said core, asource of D. G. connected'to-and' strongly magnetiz posed core-arms, a circuit opening relay, impulse coils on said less: widely;spaced-core arms and connected to sa1d'r'elay; and*a robbing the lesswidely spaced-pair ofcore" 7 arms of the flux by whichic'urrent isnor for energizing said A. hold 96 kl2 ln a' train, 'control' system, a train," 3

.ing said bar andflthe less widely 'sp'acedop-f t'rackway-mounted armature normally non influential with respect to saidreceiver but rendered effective in accordance with adverse tra-ckway conditions to constitutea *flux' bridge across the more widely" spaced-j pair of core arms, thus shunting the fluxfthrough" the more widely spacedcorearms and induc-f ing a current kick in said impulse;- coils by reason of thedrop in fluxtherethrOugh.

a corev of magnetic material having a trunk? portiondisp'osedthrough said coil and energized thereby and branches atthe endsof said; trunk portion which branches define two dis-'- one of said circuits having less reluctance;

than the other circuit andnormally consti-Y 5 V "flux, an "electro-responsive control "or .indi-i tuting' the preferred and main path forthe cating device, and an-impulse coil 'woundf f' around the normally preferred flux circuit, 5

said last mentioned coil being so electrically 1' associated with said electro r'esponsive device that said device remains undisturbed during and only during the presence of normal flux in said preferred circuit; and'a trackwayinounted armature normally non-influential coil which causes appropriate actuation of core arms which are less widely spaced and the electro-responsive control or indicating device, said trackway armature comprising a magnetic core and a choke winding on said core which when closed renders saic core ineffective as a flux shunt.

14. In a train control system, a train-carried receiver comprising a magnetic core of H-form, one pair of opposed arms of which are more widely spaced than the other pair,

a coil on the middle bar of said core, a constant current source energizing said coil, an electro-responsive control or indicating device, and coils on the pair of opposed core arms which are less widely spaced, said. arm coils being so electrically associated with said electro-responsive device that said device remains undisturbed while and only while the main stream of the core flux passesthrough a trackwa-y-mounted armature normally noninfluential with respect to said receiver but rendered efiectifze in accordance with adverse trackway conditions to constitute a flux bridge across the more widely spaced pair of opposed core arms,thus robbing the coils on the other pair of opposed arms of the flux normally existent therein, said trackway armature comprising a magnetic "core and a choke winding on said core. which when closed renders said core ineffective as a flux bridge. V

15. In a train control system, a train-carried receiver comprising a magnetic core ot' H-form, one pair of opposedarms of which are more widely spaced than the other pair, a coil on the middle bar of said core, a constant current source connected to and energizing said coil, an electro-responsive control or indicating device, coils on the pair of core arms which ar less. widely spaced, and a source of D, C. weakly energizing said coils and electro-responsive device; and a trackway-mounted armature normally non-influential with respect to said receiver but rendered effective in accordance with adverse trackway conditions to constitute a flux bridge across the more widely spaced pair opposed core arms, thus robbing the coils on the less widely spaced pair of opposed arms of the flux normally existent therein and cans ing a current kick in said coils which opposes the D. C. energizing the electro-responsive device, said trackway armature comprising a magnetic core and a choke windingon' said core which when closed rendersisaid core ineliectiveas a flux bridge. r

16. In atram control system, a-train-carried receiver comprising a magneticcore of H-form, onepair of opposed arms of which are more widely spaced than'the other pair, a coil on the middle bar of said core, a main source of D. G. connected to said coil and polarizing said core, an electro-responsive con.- trol or indicating device, a second, and comparatively weak source of D. C., and coils on said less widely spaced pair of opposed core arms which are so connected in aseries-cir cuit with said device and saiclweakDl C. source thatthe flux set up in said less widely spaced arms by said'mainD. C. source is augmented by the flux therein set up byisaid weakD. C. source; and a trackway-mounted armature normally non-influential withrespect to said receiver but rendered effective in'accordance with adverse trackway conditions to constitute a flux bridge across the more widely spaced pair of opposedcore arms, thereby robbing the less widely spaced arms of flux and generating in the coilsdisposed thereon a current kick which opposes and overcomes the D. C. provided by said weak D. C. source of energizing said electroresponsive control or indicating device,said trackway armature comprising a magnetic core anda choke winding on sald core which when closed renders saidcore ineffective asa flux bridge.

17. In a train control system, a train-carried receiver comprising a magnetic core of H-form, one pair of arms of which. are more widely spaced than the'other pair, a coil on the middle bar of said core, a source of A. 0. connected to andenergizing said coil, an A. C. holding relay governing a control of indicatice ing c1rcuit,'relay energizing coils on said less 7 I v widely spaced pairof opposedcore arms in which current is normally generatedby A. C.

' flux in said less widely spaced arms set up by the coil on said middle bar; and a 'trackwaymounted armature normally non-influential with respect to said receiver but rendered effective in accordance with adverse trackwayf conditions to constitute a flux bridge across' the morewidely spaced pair of opposed core arms, thus shunting and robbing the less widely spaced pair of core arms of the flux by which current is normally induced for energizing said A. C. holding relay, said trackway armature comprising a magnetic core and a choke winding on said core which when closed renders said core ineffective as a fiuxbridge.

18. In a train control system, a train-carried receiver comprising a magnetic core of 'H-iiorm, one pair of opposed arms of which are more widely spaced than the other pair, a coil on the middle bar of said core, a source of D. C. connected to and strongly magnetizsaid bar and the less Widely spaced op} posed corelarms, a circuit opening relay, 11npulse coils onsaid less Widely spaoedicore v arms and connected to said relay; and a track Way-mounted armature normally JlOlI-lnfllb enti-al With respect to said receiverubut rendered effectlve 1n accordance W th adverse trackway conditions to constitute a flux bridge across the more Widely spaced pair ofcore arms, thus shunting the flux through the more Widely spaced-core arms andindu'cing a cur rent kick'in said impulse coils by reason of the :drop influx therethrough, said trackway armature comprisinga magnetic core and a choke Winding on saidcore which When closed renders saidcore ineffective as a flux bridge. DANIEL HERBERT SCHWEYEB;

as. F

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