US2313903A - Remote control system - Google Patents

Description

March 16, 1943. J. J. VAN HORN REMOTE CONTROL SYSTEM Filed Aug. 16, 1941 SQQQ INVENTOR -11 J WmHWn BY I HIS A'l TORNEY 5 EQQQ bxhw Patented Mar. 16, 1943 UN TE! S TES TE OFFICE 2,313,903 I armors CONTROL sys'rniu James J. Van Horn, Pittsburgh, Pasa ssignor to The Union Switch 85* Signal Company; Swissvale, Pat, a corporation of Pennsylvania Ani ist August s, 19 1, Serial 1516'; 407,201

1 2 Claims.

' My invention relates to remote control systems, and more particularly to centralized traffic control systems for railroads for the control of railway signals, track switches or the like from a central office, and'for the indication'of such devices at the"control'omcel' 5 I One obie'ct'of my invention is the provision of means for'at times'ccfintroliing a visual indicator at the 'oflice accordi g to" the condition of the corresponding device in' the f eld and at other times controlling such device accordingtoth'e position of a inanually'pperable lever at the ofiice over the sameime channel, by means of continuously transmitted codes of impulses 'oi a istinctive frequency. The system "of my invention is arranged to' employ existing communication circuits in order to eiiectthe transmission of such controls and indications reliably and'economically over long distances, and possesses a high degree of immunity against any interference resulting from the jointuse of the same line wires by other communication facilities or from any foreign current inte'rferencelikely to occur in long distancefline circuits. v My invention is an improvement upon that disclosed in a copending application for Letters Patent of the United $tates Serial No. 409,287, filed June 28, 194 by Gk Baughman,--ior Remote control systems, and like that of Baughman, in its specific embodiment is illustrated as arranged for thecontrol of a 'manual block signal for governing trafiic movements intoa stretch of track not equippedwith trackci-rcuits; and for continuously indicating at the control ofilce when such signalis in its stop position."

The apparatus oi my invention is adapted to use line wires which are also used withoutinten ference, by acentralized traflic control code'system of the impulse code type. A feature of my invention resides in arrangements for using such impulse codes, transmitted intermittently, for selecting the direction 'of transmission for noninteriering continuous codes of the frequency typeQoVer the same line wires. 7

I shall describe one iorm of apparatus embodynovel features thereof in claims.

Referring to theacco'mpanying drawing, the lineardiagram at the-top represents a 'stretch of railway track havin'ga portionincluding; a track switch WI. Itis to be understood that'switch WI is controlled from a tower Al by means of a centralized traiiic control system of the im pulse code type, such for example, as'that disclosed in Letters Patent of the pinited states No. 2,229,249, granted January 21, 1941;. to L. V. Lewis,

ing my invention and shall then-point out the for Remote control'syste ns. When switch'Wi is reversed, it connects this portion with astretch of single track" extending to a second tower AL constituting a manual block?" having a short detector section with a track relay ZTS directly in advanc'ebf signal R2, but otherwise not provided with track circuits, and over which train move ments aregoverned by the manual block signals R2 andL'L Sigh'aI R2 is'gover'ned by'the'appara'tusof my invention ashereinaft'er described, by remote :contror fromtow'e'r A'I, while signal L4 is'm'anually controlled by a local operator at l aw Mu, 'Ihe'reierence characters Y and Z designate two line wires extending between towers Al and A2 which provides; telephonechannel which may 'be used for the transmission"ofinformation to the operator at trSwerAZ as required 'forthe manual control ofs'ignal' lii ifandfor OSfing or reporting'the'pas'sag'eof a complete train, or'reporting the "position of signal 114 to the operator Thline wires Y and Z also provide a line circuit" for "th im'pulsecode system by Which the track switch WI andother apparatus included withintheC. T. C. territory but not'shov'vn herein,-isgoverned from tower Al."

This line circ'uit is normally closed and energized'fr'om a'cen'tral office batteryitli "and comprises a metallic circuit" including line 'wire's Y and'Z in "series; the windings 'ofc'ode responsive line relays BR, 13, etc; fofcontrolliiig the coding units oE theC. T. Cf. system; and also including contacts or transmitter relays such as OT, IT, etcll by mans ofivhich different impulse codes are delivered "to the line circuit. This IiheCirc'i'i'i't as shown differs frohfthat shown'dn the abovementioned Lewis patent, in that suitable low'*pa-ss-""filters are" interposed between 'the C'. rc' ppaiams and the linewires in the man'- ner shown in'll'ig. -1 of Letters Patent ofthe United States NO. 2,208,616," g'ral'itd July '16, 1940, to George W. Bau'ghman -forRemote control apparatu's'} For simplicity only'the C. T. C. officeu'nit'and one station unit'are shown herein, and these only in diagrammatic form, since thedetails of construction and operationof this apparatus may be ascertained from the abovementioned patents. a

ln'addition, the line wires Y and Z afford a simplex or phantom circuit-comprising the two line wiresinmultiple with earth return, which may be used either as'a control line channel over accordance with my invention, by means of noninterfering impulse codes transmitted over the same line wires through the medium of the above-mentioned C. T. C. system. The line signals transmitted over the control and indication channels are preferably of the continuous code type, and in the specific form shown, are transmitted as impulses of alternately opposite polarity derived from a direct current source and having a constant frequency of the order of 75 to 180 cycles per minte. The impulses are refrom the local direct current source to the ince'ived by the line relays FBI and PR2, and these relays govern apparatus which is selectively responsive to frequencies of this order, which apparatus is adapted to convert the impulses into pulsating direct current to govern the signal relays ZHR and ZDR and the indication relay ZNK.

Signal R2 is illustrated as the usual three-position color light signal having lamps G, Y and R for indicating clear, permission or stop, respectively. Lamp Y or G is lighted when one or both, respectively, of two signal relays 2I-IR -dication line channel, and since this channel employs a ground return, condensers are interposed so that the same battery may be used for the control of other circuits which are to be maintained free from grounds, in accordance with the usual practice in the railway signaling art.

This indication line channel may be traced from ground at condenser 16 over contact 5 of relay ISGCTI, back contacts 9 and ll! of relays ZHR and 2D R to terminal B, thence through the 7 local source of currentto its other terminal C and ZDR, and also the track relay 2TS for the 7 short detector section in advance of signal R2 are energized and lamp R is lighted when relay 2TS or 2HR is deenergized.

The signal relays 2I-IR and ZDR are governed by continuous codes of frequencies of 75 and 180 cycles per minute, respectively, transmitted over the control line channel in accordance with the position of a signal control lever 2L and. of a push button ZPB, as hereinafter pointed out.

Lever 2L has a dual function, and in addition to governing thesignal relays it also governs the transmission of QT. C. codes and in this respect functions like lever HK, shown in Fig. 5 of the above mentioned Patent No. 2,229,249. That is, with lever 2L in its right-hand or reverse position, if a starting key SK is pressed momentarily, an impulse code is transmitted by the oflice unit of the C. T. C. system during which wire N14 is energized, and this code is received selectively by the station unit at the location of'signal R2 to energize wire 85 momentarily to/pick up a signal control relay RHS. Relay RHS then remains picked up overa stick circuit including wire 86 until a different code is received in response to a subsequent operation of key SK with lever 2L in its left-hand or normal position, whereupon relay RHS releases due to the deenergization of wire 86. The reference characters for those partions of the C. T. C. system shown herein-are the same as those for corresponding parts in Patent No. 2,229,249, in which these operations are more fully explained, relay RI-IS, for example, being shown in Fig. 8 of the patent. It is to be noted, however, that the circuits for relay RHS shown herein differ from those of the patent, in that as shown herein relay RHS is not released when a train enters the associated track section and furthermore, it cannot be released by a C. T. C. code unless the signal relay ZHR is already in its release position.

The indication relay 2NK controls a lamp ZRE for indicating to the operator when the manual block signal R2 is at stop, and is governed over the indication line channel by a continuous code having a frequency of 180 cycles per minute.

With relay RHS released, as shown, a circuit is closed from one terminal B of a local source of direct current over its back contact 3 and the back contact 4 and winding of a relay contactfi of relay IBOCTI, resistor [1, back contact H of relay RHS to the mid-point connection of condensers 1, thence through condensers 7 and coils 8 to line wires Y and Z and through similar coils 3 and condensers 7 at the oflice, front contact I2 of relay ZNK, and the winding of the line relay PR! to ground. When relay 2NK is released, the indication channel may be completed over its back contact I2 provided the normal contact 13 of lever 2L is closed, as

shown.

The line relay PRI isa sensitive relay of the stick polar type and its contact is operated to the right or left according to the polarity of each impulse delivered by relay I88CTI and is held magnetically by a' definite biasing force in its relay of the usual railway signaling type, and

when the indication line channel is completed as described its contacts repeat the code operation of the contacts of relay IBBCTI, operating times per minute,

Relay CDI delivers impulses of alternately opposite polarity to a decoding transformer and thence to a resonant decoding unit IBUDUI including a tuned circuit and a rectifier by means of which the normal indication relay ZNK is selectively energized. These decoding circuits are substantially similar to those for relay K3 shown in Letters Patent of the United States No. 1,773,472, granted August 19, 1930 to Paul N. Bossart, for Railway traific controlling apparatus, and provide a high degree of selectivity for the reasons explained in the patent, so that relay 2NK responds selectively to 180 code only.

A front contact 14 of relay ZNK controls a red lamp 2RE located on the operators control panel at the oifice adjacent the signal lever 2L} Lamp ZRE therefore is normally maintained lighted only aslong as the communication line extending to the location of signal R2 is energized and intact and the back contacts of relays 2HR, ZDR and RHS remain closed;

It will now be assumed that the apparatus is in its normal condition as shown, and that the operator at tower Al, knowing that the manual block is unoccupied, reverses switch WI by me'ans of the C. T. C. system and then reverses lever Pr s s the starting key SK w t h i Y (mt-"r a 1 Q0 -left-to a t. 1 6 e e 2 o circuit-' from terminal B "arrd normal agita e gentleman-* iPBfthe hack earnest and Winding-Of reIay 'l-E C 'I] to termihaf QJ- Relay afcod trarismittefi'sim'ilartdlBflCTfin type but dilferin themes in that "when ener gizecl relay 150T ope aftes' its ontacts' re eatecl-ly .2 ont' co'ri'tacts conditions the continuous code nee re ay PRl',"bht renysrm and cnz n'pw eisrate- 75 times per minute and relay 213R, con- 6 He'd by the decodin'gunitlwDUl consequentl impulses or alternataybpposite polarity to the zissatiateal decoding transformer an these impinssare rectified bycb'ntaet" *of that relay td' energize relay 2BR. *"The circuits for relay zi-IR correspofi d to those for" relay-H in Letters and relay2HR'is responsive=toeither"'75or" 180 'codebut" noh responsiveto foreignalternating currents such a's might be supplied thereto, for example, through the d'ecbdih'gtransformer" from atf'alternating current battery charger connected a'ro'ssterminals B and C of the-local source."-" I nemy-ammo; hicks uppl'ighting lamp Y to cause" ="signa1"R2 "to 'display a permissive *indica ti'on,"ai1d "contact 26 df relay 2BR- c'onnectsterxfiihal B' t6 Wire 89 of the -stati'on coding unit of the 'C. T. 6'; system to initiatethetransmis ston of an indication code as "explained in Patent No? 2,229,249; to pickflp the in-dicaticn stick re'layi ZHK at the ofiice. thereby lighting'the'sig rial" indication 1amp-2YE.-"-

It will now be assumed that the operator presse's-thepushbu'tton' ZPBw-The closing" of crfta'ct "21 energizes "relay- C-T2,= similar to ISBGTI', in p13i0f"TCT; and'contacts '20 and 2815i "push bl'ltton 21 B interpose thepo'le changer canteens and' wofrelay' 1'80671 2 in thecontrol line channel in series with the oflice battery to both energized to light 1am SiEnaT'RZ toin'di'cate clear. Similarly; @0 61 may 213R applies energy to wire I itiate by the TLC. system Eo p'Ick up the indication stick relay IDK to hght lamfiiGE'at theofiic'e in place er lamp *Itwill be apparent from the foregoing that to jcause 's ignal R'z 't'o' indicate permissive or clear",

the 'op on"- of two independenttransmission systems is 1nvolved,that"is relay RHSisffir'st pielli i by n ilfibuI'se'bOde' and l-el ays lHRand IDR' aYE they? picked up by continuous codsl After rela -ma es once been picked up, its com tact g fib1a-re1ay l ans nicked" uplocally; so that the-eontinuity dfthe controllinechannel eanhot be interrtiptd inadvertently by my C ,t

iv' or clar sole'ly by the -continuous" codenamein 8d hver th lever entacts ls andle;

heassii iied' 'tha-t'a train governed by sigr'xa R? now enters the detector tracks'ection,

releasingthe tr I k relay 2T8; The cl'rcmpi ng' of cdfitaemz df relay ZTS causes signal'Rg to"indi'- cate stop, even through relays ZHR and {213R remaiflenerg'i zed. The dr0ppingof contacts 33 and-34 err a'yITSinitiateS an impulse" code which releases relays and EDI; ana'p cks u'fp' tfie -tra'ck indiction stick relay" ZTKQ so that lamb QTE iS lightedfand -1arhb-2GE' or is extinguished, "Idutl'am p ZRE does nct become d J i l: III I Ll," lt" w ll' b -seeiihat the track relay 2T5 is a stick relay anq wi-ll remainieleased after the 'va'cates""the detctorsectiQn unless relay LRHS i's' released to *close it's back contact 35fbiit relay RH "no-vfhl'c l energiied over contact 3! dfrelaiy 2HRQ-- To pick ub I relay 2T3, the 015'- erator must first restore lever 2L to normalto d-i tifiuthe-continuouscodeand thereby releasey ZHREandmu'St then operate'key SK momentarily-"t6 transmit an impulse codeto releaserelay RHs; Assuming "that the operator pe forms the's'-operationsfthe release of relay RHS' v'vithrelays-"231Rand ZDR de'energized'wifl re-initiate the transmission of cedeover the indication line eharinel to-bicli up rela'yiNK' and light lamp ZRE. Then when the train vacates the detectorsectiomrelay ZTS picks up over contadt 'si fif relay HHS; alfid by deeliergizing wire '91-, initiates hn {impulse code to release relay Z 'IKK thereby"extinguishing lamp ZTE and restoring th abpa'ratus'to the normal condition as Itwill be seen that relay ZTS functions as an ordinary 'n0n-stick*"1 'e1ay'when a trainmoving fromfiighfltoleft passes through the detector section; since in' this"case'lever' 2U remains in its normal position and relay 'Rrrs" 'is not picked upkrJ 51'" Q .l

i -It will also be seen that the arrangement is such as to insure-thatlever 2L"is returned to normal after each train movement from left to rightpast signal R2, and that relay 2TS cannot be bickdupafterthe train 'vacates the detector sectionas a'result of atemp orary failure of the circuit' 'fdr controlling signal R2 as long as'lever 112 s reversed:

"--*="It--is- 'to-'be*understood that my invention is notlimifidto th'us'e'hf the particular type of contint-ions codesignals described herein nor to thenseof a'simplex line circuit for the trans -C. codei and thsigriall is held at permisv mission of these signals but other well-known forms may be substituted, for example, alternating current of a commercial frequency such as 60 or 100 cycles per second which is modulated or interrupted at a low rate such as 75 to 180 times per minute, may be used, as employed for controls in the system of the above-mentioned Baughman application. Also such currents or carrier currents of higher frequencies which may also be used may be connected so as to employ the line wires Y and Z in series, like the C. T. C. line circuit, with frequency discriminating apparatus at each point of connection, in place of the parallel connection with ground return, as shown, such an arrangement being preferred under certain circumstances, as for example, when my invention is applied to a railroad employing electrical propulsion and deriving the energy for the propulsion of trains from circuits having an earth return. In any case, the same line circuit may be used for transmission of continuous codes of like character in either direction, with the same insurance against improper operation of the receiving apparatus by the transmitting apparatus at the same end of the line circuit as provided in the particular form herein shown and described. i

Thus for example, the 180- code transmitted over the indication line channel holds relay 2NK picked up, and front contact l2 of that relay maintains the continuity of the indication line channel regardless of the position of lever 2L untilthe operator disconnects the source of the indication code by picking up relay RHS. Similarly, the 75 or 180 code transmitted over the control line channel holds relay Zl-IR' picked up, and contact 3| of that relay holds relay RI-IS picked up to mantain the continuity of the control line channel until the operator disconnects the source of the control code by restoring lever 2L to normal.

Although I have herein shown and described only one ,form of remote control 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 the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a remote control system, two stations connected by line wires, a code transmitterat each station for delivering impulses to said line wires, a line relay at each station adapted to receive such impulses, a movable contact at each station which in a first position connects the associated code transmitter to said line wires and in a second position connects the associated line relay to said line wires, and means controlled by each line relay when receiving impulses from said line wires with the associatedmovable contact in its second position for maintaining said associated movable contact in its second position as long as the line relay continues to receive impulses.

2. In a remote control system, two stations connected by line wires, a code transmitter at each station for delivering impulses to said line wires,-a line relay at each station adaptedto receive such impulses, a movable contact at each station which in a first position connects the associated code transmitted to said line wires and in a second position connects the associated line relay to saidline wires, manually operable means for governing the operation of the movable contact at one station to its second position, means remotely controlled by said manue ally operable means for governing the operation of the movable contact at the other station to its second position, and means associated with each movable contact when operated to its second position for maintaining it in such position as long as the associated line relay is receiving impulses from said line circuit.

3. In a centralized trafiic control system for railroads, a stretch of railway track including a block section, a signal for governing trafiic movements into said block section, a signal relay for clearing said signal, asignal control relay at said signal location; a signal lever and an indication relay at adistant control oifice, a-first and a second line circuit connecting said signal location with said ofiice, means for transmitting impulse codes over the first line circuit to pick up said signal control relay when said lever is reversed and to release said signal control re.- lay when said lever is restored to its normal po; sition, a control channel including a reverse contact of said lever, said second line circuit and a front contact of said signal control relay for ,at times continuously energizing said signal relay, and an indication channel closed in response to the return of said lever to its normal position including said second line'circuit, a back contact of said signal control relay and a contact closed when said signal indicates astop for continuously energizing said indication relay. 7

A. In a centralized traffic control system'for railroads, an ofiice and astation connected by a line circuit, a signal-at said station, a signal relay for clearing said signal, a signal control relay at said station, a-signal lever and an indi cation relay at said ofiice, means efiective when said signal lever is reversed and said sign-a1 7 control relay is released, and said signal is at stop,

to energize said line circuit at'said station and to connect said indication relay thereto at said office, and means including a second line circuit for controlling said signal control relay in ac 'cordance with the position of said signal lever.

5. In a centralized traific control system for railroads, an ofiice and a station connected by line wires, a signal, a signal relay and a signal control relay at said station, a signal lever and an indication relay at said oflice, a control circuit for energizing said signal relay including a "source of current at said oifice, a reverse contact of said lever, said line wires, and a front contact of said signal control relay, an indication circuit for energizing said indication relay including a source of current at said station, aback contact of said signal control relay, said line wires, a normal contact of said lever, and a contact closed only when said signalindicat'es stop, means controlled by said signal relay when energized for clearing said signal, and meansin eluding a second line circuit for governing said signal control relay to prepare said control'or indication circuit according to the position of said signal lever.

6. In a centralized traffic control system-for railroads, an ofiice and a station connected by line wires, a signal, a signal relay and a signal control relay at said station, a signal lever and an indication relay at said oflice, a. control circuit including a reverse contact of said lever.

said line wires and a front contact of said signal control relay, an indication circuit including a back contact of said signal control relay, said line wires and a normal contact of said lever, means at the office for supplying current periodically varied at a low frequency rate to said control circuit to selectively energize said signal relay, means at the station effective only when said signal indicates stop to supply current periodically varied at a low frequency rate to said indication circuit to selectively energize said indication relay means controlled by said signal relay when energized for clearing said signal, and means controlled over said line wires for at times governing said signal control relay to prepare said control or indication circuit according to the position of said signal lever.

7. In combination, an c-ilice and a station connected by line Wires, a manually operable lever at said oflice, a control relay at said station governed in accordance with the position of said lever, a signal relay at said station, an indication relay at said ofiice, a control circuit for said signal relay including a reverse contact of said lever, said line wires and a front contact of said control relay, an indication circuit controlled by said signal relay, including a back contact of said control relay and said line wires, for controlling said indication relay, and means for completing said indication circuit in response to the return of said lever to its normal position comprising a normal contact of said lever.

8. In combination, an office and a station connected by line wires, a manually operable lever and an indication relay at said office, a control relay at said station governed in accordance with the position of said lever, a movable device at said station, a control circuit including a reverse contact of said lever, said line wires, and a front contact of said control relay for selectively controlling said movable device, an indication circuit including a back contact of said control relay, said line wires and said indication relay for selectively indicating the condition of said movable device, and means for completing said indication circuit in response to the return of said lever to its normal position comprising a normal contact of said lever.

9. In combination, an oilice and a station connected by line wires, a manually operable lever and an indication relay at said office, a control relay and a movable device at said station, a control circuit including a reverse contact of said lever, said line wires, and a front contact of said control relay, an indication circuit including a back contact of said control relay, said line wires and a normal contact of said lever, means at the oflice for supplying current periodically varied at a low frequency to said control circuit when said lever is reversed, means at the station for supplying current periodically' varied at the same low frequency to said indication circuit when said movable device occupies a given position, means controlled over said control line circuit including selective circuit elements tuned to electrical resonance at said low frequency for selectively controlling said movable device, means controlled over said indication line circuit including other selective circuit elements tuned to electrical resonance at said low frequency for controlling said indication relay, and means for operating said control relay in accordance with the position of said lever.

10. In combination, an office and a station connected by line wires, a manually operable lever and an indication relay at said office, a control relay and a movable device at said station, means at the office and station for delivering spaced impulses of alternately opposite polarity to said line wires, polar relays at the ofiice and station operable alternately between two positions in response to such impulses and held magnetically in their last operated positions between impulses, a control circuit for transmitting said impulses from the ofiice to the station including a reverse contact of said lever, said line wires, a front contact of said control relay and the polar relay at said station, means effective when the polar relay at said station is operated repeatedly by impulses received over said control circuit for controlling said movable device, an indication circuit for transmitting said impulses from the station to the office including a back contact of said control relay, a normal contact of said lever and the polar relay at said Ofi'lCE, means effective when the ofiice polar relay is operated repeatedly by impulses received over said indication circuit for controlling said indication relay, and means for operating said control relay in accordance with the position of said lever.

11. In combination, an office and a station connected by line wires, a detector section of railway track at said station, a manually operable lever at said oiiice. a stick track relay normally held energized over its own front contact and the track rails of said section, a signal for governing traffic movements into said section, a signal relay and a signal control relay, a circuit for clearing said signal including front contacts of said signal relay and said track relay, a line circuit for maintaining said signal relay energized including a reverse contact of said lever, said line wires and a front contact of said signal control relay, a pick-up circuit for said track relay including a back contact of said signal control relay and the track rails of said section, and line controlled means for energizing said signal control relay in response to a movement of said lever to its reverse position and for releasing said signal control relay in response to a movement of said lever to its normal position.

12. In combination, an oi'lice and a station, a detector section of railway track at said station, a manually operable lever at said ofiice, a stick track relay normally held energized over its own front contact and the track rails of said section, a signal for governing traflic movements into said section, a signal relay and a signal control relay, a circuit for clearing said signal including front contacts of said signal relay and said track relay, a direct wire lin circuit for maintaining said signal relay energized including a reverse contact of said lever and a front contact of said signal control relay, a pick-up circuit for said track relay including a back contact of said signal control relay and the track rails of said section, a second line circuit for controlling said signal control relay in accordance with the position of said lever, and means including a front contact of said signal relay for maintaining said signal control relay energized when said first line circuit is energized irrespective of the condition of said second line circuit.

JAMES J. VAN HORN.

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