|Publication number||US2377850 A|
|Publication date||Jun 12, 1945|
|Filing date||Mar 4, 1944|
|Priority date||Mar 4, 1944|
|Publication number||US 2377850 A, US 2377850A, US-A-2377850, US2377850 A, US2377850A|
|Inventors||Raymond C Blakeslee|
|Original Assignee||Union Switch & Signal Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (2), Classifications (7)|
|External Links: USPTO, USPTO Assignment, Espacenet|
June 12, 1945. R. c. BLAKEsLl-:E
REMOTE CONTROL SYSTEM Filed March 4, 1944 S www INVENToR lfaymand'laefle@ [1I/5: ATTORNEY ffm? Patented June 12, 1945 REMOTE CONTROL sYsTEM Raymond C. Blakeslee, West Allis, Wis., assignor to The Union Switch and Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application March 4, 1944, Serial No. 524,983
My invention relates to remote control systems, and more particularly to centralized trafic control systems for railroads and to the line circuits' for such systems.
Centralized traffic control systems are now arranged to use the line wires` of existing telephone circuits, a suitable system of this type being shown, for example, in Letters Patent of the United States No. 2,303,875, issued December 1, 1942, to George W. Baughman and Norman F. Agnew, for Remote `control systems. In some cases the centralized traffic control system is superimposed upon a train dispatchers telephone line equipped with selective calling apparatus for calling the operators at Ivarious telephone way stations, the` selector system beingusually of the type disclosed in Letters Patent of the United States No. 1,343,256, issued June l5, 1920, to J. C. Field.
The centralized traffic control system and the selector system are non-interfering by reason of the use of dilerent codes, that is, the selecting apparatus of each system is non-responsive to the codes transmitted by the other, but since both systems employ codes of low frequency impulses transmitted over the same line-channel through low pass filters, it is necessary toallot the use of the line to only oneV system at a time.
The selector system usually employs manually releasable code Wheels which are adapted to transmit their codes immediately when released, or not at all, while the centralized trafic control system, 'on the other hand, may be arrangedto store an interrupted code for retransmission in its entirety, as soon as the line is free.
One object of my invention is .to provide improved means for interlocking two dissimilar code systems, such as those mentioned, in such a manner that the operator of one system, namely, the call selector system, may gain access to the lineto transmit a code at any time irrespective of whether or not it is in use atfthe time by the other system, the operation of acode wheel being effective to temporarily suspend Vthe operation of the centralized traffic control system and to disconnect it from the line circuit for the duration of the selector code.
A further object of my invention is to provide improved arrangements of this character suitable for use when the control oiilce of the centralized traic control system is at an intermediate point on the dispatchers line, that is to say, at a point remote from the location of the selector transmitter.
Itis also the practice to superimpose an additional communication channel upon the dispatchers line, employing the two line Wires in parallel as one side of a simplex telegraph or phantom telephone circuit, or both. As illustrated, for example, in Fig. 1 of the above-mentioned Patent No. 2,303,875, it has been the practice heretofore to employ the bridged type of simplex circuit'in which the telegraph leg is connected to the line wires by a mid point connection to two relatively high resistances connected across the' line wires in series. This added resistance is somewhat detrimental tothe operation of the telegraph circuit, particularly -when four such connections are required, asis the case when the control olceof the centralized traffic control system is at an intermediate point on the line. This difficulty is avoided by a novel arrangement of the apparatus as disclosed herein, which provides `a low resistance path for the telegraph channel through the line connections of the centralized traiiiic control and selector systems.
One form of apparatus employing myl invention will now be described, and the novel features thereof willthen be pointed out in claims.
Referring to theaccompanying drawing, the reference characters YI, ZI and Y2, Z2 designate a pair of line Wires which extend from the dispatchers ofce shown at the left, through the territory controlled by the centralized control system. lThe physical line circuit is sectionalized atan intermediate point, at which the C. T. C. ofce is located, by interposing a telephone transformer or band pass filter 3 arrangedto pass currents in the voicefrequency range only.
The line wires provide a voice frequency communication ,channelV extending from a telephone set 5 at the dispatchersoffice over the line Wires YI and ZI to a plurality of jacks l1, such as the one at the selector station shown at the left of ranged to be energized during the rotation of any -code wheel, and a pole changer relay JPC controlled by the code Wheels.4 The periodic operation of relay JPC by any of the code Wheels J supplies impulses of alternately opposite polarity from battery 2 with interposed pauses through a low pass filter 4 and an impulse transformer 6 to the line Wires. The selector impulses normally have a frequency of 3.5 cycles per 5 second, and they serve to operate polarized selectors 'I2 so as to ring a call bell I6 at the selected station..
The territrybontrolledby the C. T. iC. system.- is to be understood to be that adjacent line Wires 10 Y2 and Z2 only. These line Wires are supplied n with current from a line battery 80 to proyidea .1. normally closed line circuit connecting the'C. T.
C. oice and a plurality of C. T. IG. .staQQIlssuch.. I as the one shown on the drawing'.,.the .C.. .1:5 system corresponding to that l.shownann `..the.. Baughman and Agnew Patent No.. 2,303.31@ here,7 inbefore referred to, except foc'etain" minor" modifications as described herein.
Fo""an understanding of my invention it is 30 deemed`siif'cieht to pli'ritmouttlit the j' codiiifg untsfredure the line'cicuit tolbews'teadily energized in"rde' r"'toplfe them m'c'n'di'tion Ato initiatie "the'transr'issiondf 'a c tdfe, or to'seleci. tively re eivea code'adtliat the 'stationtrans: A3:5 mitter are"rr'ia'intair'ied' ir'fop'eation bythe` rel sponce oftheasso "ated lin'relay's'to'the code 7 elements," becoming disabled if the 'line remain-s1` operrf'r period rnfal'ferially l'r'iger `'than any elel f ment' 'f` aA code. "The TL," 'office-coding 'nit'is'j' r40 adapted te tiansniit'eentro 'eiiesin vviiiei,trie-,-l line "ci'rciiitnis'periodically 'interrupted by the V'r'ef peated energizatioh of la transmitteday CTZ-'tol Operate the 'staiieniine relays R; which are'ef4 high"resistancebiase'd polar'type. The Cf T.' '4i eedesconsist ef cbnii'natibnsjefin'g and short cede 'elements' having` abaefrequeneytf endet "L 6 Cycles pqnd...
In drdetdmnimize code distortion wherr the iine wires'are j in "a tatie; a' rsi'stbell u" iseonnectecl arss trie line `ivir'es Y2 ndZ'Zvtprovide f '5 a discharge' patri wneni'remyo'r iiicksp t disconnectbaltteryfroin'the lirici; M
Each C. T."C.tstatiri1 'adateuto transmit in-- y dication codes"by'erierg1aing'-a'-inst relay' M `55 and 'the'nzi periodically connetingfth linev'vi'resf together..-by^"thezrepeated -pe'atieii of 'contact zi' of a transmittenrelay the' .esultinglyariation's' in the "linec'urrent causing transformer RT -to Y supply impulses of "alternatelyf'opp'osite .polarity 60 te theP eineeiinexreiay OP., which isfof 'the sti'e'kc 1' polar type,`so` that relay' OR repeats the code operation ofrelay T atthetransrnitting statidni'f "ine,5ni'st..inipu1se of ari' indicatio'rl `'cone op- .I erates the pole chanerrelay'PC attheofce-by 65 means not shown, and relay PC reverses the'polarity o'f 4the'currentsuipliedto Vthe line by'bat tery' 80, While frelay M reverses. the l'connections efor relay R' at .the transmitting station 'torendei' Y' it responsive to 'the currentof. reverse polarity. 7l0- This reversal of .the line 4polarity releases lthe'line i relays R atthe other` C. Cistatibns, .a't which. the relays Mare deenergizedso thattliesef'stations are held` in an" inactive cnditionur'it'il 'the and the line circuit is again energized by current of normal polarity.
The telephone transformer 3, which is provided to .isolate the C. T. C. line circuit from the remainder of the dispatchers line, is also arranged to block the transmission of selector codes from one section of that line to the other, and accordinglyfa selector; code `repeater provided to repeat-.,the.selectori-.codes 'delivered to dine., -wires YI and ZI into the circuit comprising the line WiresYZ and Z2, in order to operate the selectors 'I2 at ;stationsto'the right of the C. T. C. oice. The selector code repeater furthermore comp-ensatesilior theimpairment of the selector line circuitldueto the, ,connection of the line relays R in parallel withithe selectors 12 across the line weer; eeaz2..-.
The simplex telegraph channel extends from wire ,XI ethrough transformer 6 to the line Wires YI anqnZvI lin paralleLand thence to thev simplex @Oil ii.;f.r0'i1.ik1ent.er.terminal of which it eX-. tendshover oneb or another of a'plurality of loweresis'tance circuit portions provided injaccordance with a feature of my invention, to line; wires Y2 andv Z2, thereby by-passing transformer-- 3, and i over thezlinewwireslvY2and Z2 in parallelJ to the simplex coil IQ. and thence to Wire X 2.In order "i to provide ra'ci/rcjuit patlrpf uniformly low re-g sistance "for the telegraphcircigitwunderfall 'con-- ditionsof operation of theC. T. C. and selectorn systems,"V the Vvarious relaycontacts in the -Ci- T. 1f C. line circuit have beenl made of theconti-nuity` transfer type, as shovvn, Vand.' the'centero--terminalof coil v'isI connected -resp'ectivelyftothe-center 'M terminals of resistorL I Il, 'of batteryy, and of transformer; I6, the'lastnamedconnection includingv a resistor II-. i The-values pf; resistors l; I0 and II are made'relativelylow;fandchosenso., as to present substantially thesame resistanceto 1 the telegraph currents iiowing-from coilV 8 totheline Wires Y2 and-Z2, irrespective ofthe-positions of relaysOT-and JBA'P'. jIt vs /ill"be readily apparent that -theLtelegraph-channelfis' notdis' turbed by the operation lof the pole'changer relay f PC, -s ince-th`ismerely-interchanges wires-[Y2 and-- Z2 ini the `circu it,norWhew-wires jY? and'Z2 arel connected togetherduring-ethe'eperation'of a' transmitter at aC. T-. C. station-,-andefurthen thatethe vresistanc-:e of the bypass circuit-'may be made materially lowerethan' that-of the usual simplex connection comprising resistors i bridged r f across the linewires?thereby'permitting are-- duction inthe voltage-irnpressed -uponthe 'tele-f' graph circuit-andcorrespondingly-decreasing'the fdetrimental effectseof flinefleakagef Consideringnovv the Imode of operation-:ofthe I selectorsystemvandnassuming for thee-present thatlthea T. s'ystemiremains-in: its normal'vvat rest' condition; whenacode Wheel Jeis released. :A1-'1 by the operator-.at the dispatcheris oicefits initial f movement .completes a' circuit' from-one .-t-erminalf B oasuitableilocal source ofcurrentover con-1 tact 96! to :wheel-J endet-hence through .relayexIB to the othenterminalCiof'the sourceythisircuit remaining` closed. until-the Wheel: Jccompletes itsi rotationv and .lagainoccupies ,f its. normal positioneas shown. Relay JB therefore-'picksfurn and :its:y contaotsa and b-.bycconnecting-.battery :to transformer .E `.cause the delivery.of-ia-prelinfiinary=im transmission of thndicationlcodeis` completedla PR throughiaezloyv 'passslienllftoctlansiormern.
from terminal B at the back contact c of relay MP,-through relay JBAP to terminal C so that relayv JBAP picks up to connect transformer I6 to the linewires Y2 and Z2. This preliminary impulse is not repeated into the line Y2-Z2 because it is delivered to ,transformer I6 before relay J BAP picks up.
The code wheels J are arranged so that a period of at least one second elapses after the contact spring 96 makes contact with the code wheel, before it engages the first tooth to complete a circuit over contact spring 9J' to pick up relay JPC. Relay JBA is made sufliciently slow release by the connection of a condenser CI Vof large capacity across its winding to bridge this interval as well as the intervals between the successive impulses of the code. Relays NR and PR respond to the code impulses deliveredto the line wires YI and ZI by` relay JPC, relay NR maintaining `relays JBA and JBAP picked up until the code wheel completes its rotation, and relay PR repeating the operation of relay JPC to deliver the code to the line `wires Y2 and Z2.
During the transmission of the selector code the C. T. C. line battery 8U is disconnected by the `opening of back contacts b and d of relay JBAP, and the telegraph channel by-pass from coil 8 to the line wires Y2 and Z2 through battery 80 is replaced by the equivalent one from coil8 through transformer I6 without interrupting its continuity. Since the C. T."'C. coding units provides a circuit extending over its front con- OT without interrupting the continuity of the telegraph channel, and it follows that the telegraphic transmission over this channel is not in`- terfered with by the C. T. C. transmission.
Relay MP is provided in accordance with a,
modification of the C. T. C. system disclosed in a pending application for Letters' Patent of the United States, Serial No. 496,907, flied July .31, 1943, by Arthur P. Jackel for Remote control systems. In this modification the control elements of the code are each registered during the reception of the next succeeding element without storing them until the line is closed at the end of the code, as heretofore. Relay MP is energized for the duration of the control code and tact c to terminal B at the reversecontact a of relay OR over which relay JBAP is energized in response to the energization of relay JBA as in the preceding examples, provided relay JBA picks up during the transmission of a line open code element, that is to say, while relay OR is rerequire the line circuit to be steadily `energized to condition them to transmit and to receive codes,\the C. T. C. system becomesdisabled during the interval between the preliminary impulse and the first impulse of the selector code,` remaining in that condition until after relay JBAP releases at the end of the selector code. The station line relaysvR being of the biased polar type, pick up momentarily in response to alternate impulses of the selector code, but since they were all released for a relatively long period when relay JBAP picked up, vand since they do not become steadily energized as required to condition the station coding units to receive code, until yrelay JBAP releases, the C. T.V C. station units are nonresponsive to the selector codes, regardless of their code character;
Thefoperation of` contacts c and e of relay JBAP disconnects the ollce line relay OR from the impulse transformer RT and holds it reversed for the duration of the selector code, thereby holding the C. T. C. ofllce receiver inactive.
Assuming next thata selector code is initiated while a. C. T. C. indication is being transmitted,
-it will be clear `that the energization of relay JBAP, by holding the C. T. C. line open, will disable the C. T. C. transmitter, interrupting its code before the selector code begins. It will be understood that the C. T. C. station units include stor..
age means such that an interrupted code is retransmitted in its entirety as soon as the line becomes free so that in this case' the -selector code and the C. T. C. code will be transmitted successively. l
Considering next the transmission of a control code by the C. T. C. office coding unit which code, as already mentioned, is generated by opening and closing the line circuit including battery 80 by the periodic operation of the office transmitter relay OT. Each time relay OT` picks up, the simplex channel by-pass through battery 80 is replaced by one from coil 8 through resistor I0 by the operation of contacts b and d of relay versed. On the other hand,if relay JBA picks up during the transmission of a long line closed element, the C. T. C. system retains control of the linelong enough to complete the transmission of that element, relay JBAP becoming energized in response to the reversal of relay OR when the element is terminated. In this manner the conversion of a long element into a short one by the action of relay JBAP is prevented, thereby avoiding the improper response to that element as received at the field station.l In either case, relay JBAP becomes energized to free the line prior to the transmission of the first impulse It will be evident that in general the operator of the selector system will have no knowledgeof whether or not the line circuit is in use by the C. T. C. system. Such knowledge is unnecessary as he is free to gain access to the line at any time to interpose selector codes without causing any of the C. T. C. codes to fail to be transmitted,l and Without causing interference between these codes and the selector codes, the onlyeifect being to suspend the operation of the C. T. C. system as long as he continues to use the line. Furthermore, this result is attained without the provision of any additionalcircuits between the dispatchers oiilce and the C. T. C. ofiice, and without impairing the full efficiency of utilization of the line wires thereby enabling the C. T. C. system to be superimposed upon a portion of a simplexed dispatchers telephone line without in any manner impairiig its normal mode of operation.
In the foregoing I have assumed that the dis- 6 will replace transformer I6 in the circuits associated with the C. T. C. office coding unit, the
arrangements for providing a low resistance telegraph channel being equally advantageous under this condition.
Although I have herein shown and described but one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US2420871 *||Feb 1, 1945||May 20, 1947||Westinghouse Electric Corp||Control system and telemetering circuit|
|US4113986 *||Oct 21, 1977||Sep 12, 1978||Bell Telephone Laboratories, Incorporated||Telephone controlled lock release arrangement|
|U.S. Classification||379/102.1, 246/3, 379/108.2, 340/12.31|