Патент USA US2396134

2,396,134
Patented Mar. 5, 1946' ’
UNI TED STATES ' ~ PATENT; QFFmE
2,396,134<
REMOTE“ ("JGNTRGE SYSTEM"
The Union Switch & Signal Gunman-y,v
Swiss- >
vale,-Pa.,, a corporation‘ of, Bennsxlvania.
ApplicationDecem-ber 17, 119453;, Serial; No: 514,641‘ V
18v Glaimsc (c1. mgr-ass):
My- invention- relates to ‘remote control ‘sys
toms,- and more particularly to centralized ‘traffic
control systems for railroads for'the control of
railway signals or other tra?ic controlling‘devices
from a central point of control: such as a train
dispatcher’s o?ice; and‘ for'the, indication of such
devices or of train movements ‘at the control
o?ice.
The transmitting’ portion of the system ‘of ‘my
invention is claimed in my‘divisionalapplication,
Serial No. 561,563; ?ledv November’2, ’1944,_ for
Transmitting apparatus for remote control sys
tems.
‘
One’ object of‘ my invention isthe, provision of
a system» suitable for the direct control of‘ un
attended manual block signals employing" cur
rentsof such-a ‘character that they'maybe trans
bytrain'iorders, supplemented by ‘manual
control‘ 'o'f-ithe: signals.
of’ my inventiondprovides facilities by which ‘the
signals“ at ‘each of ten stations-“may- be selectively
controlled‘ to give-proceed; permissive 'or- stop in
di'cationsiiby the lighting of the lamps-G, Y‘ or
respectively of the signals
and; RH, in re
sponse tothe operation of suitable push "buttons
PS‘ and" PF‘at the control 'o?‘rce, and. also pro
vides‘meansrfor lighting selected indication lamps
Eat the o?ice to’ indicate whengthe corresponding
signals are at stop; each‘ lamp; being lighted
automatically-when atra-in enters. the correspond
ingudetectorsection.
their‘ use for other communication purposes;
cation'transmitting-relay Ll‘; At?ve 'of‘t'he sta
20 ti'ons, adjustable connections are made to contacts
a1 and‘ e-‘of‘relay‘Rl' to render relay>R3i responsive
to line ‘signals ‘when relay RI is energized. ~At
theremaining- ?ve stations; the connections are
shifted‘to contactsw and‘ c ‘of relay R2 to render
relay R3; responsive to line“ signals when relay
R2‘ is energized. Each selector relay R3 is‘ ar
ranged‘. to’ he energized‘ through "a recti?er unit
I'll, when‘ the unit is supplied with ‘alternating
in which the codes-comprise- di?erent sequences
of impulses of alternating "currentsof 'diiferent
frequencies‘ within a hand of frequencies prefer
ably in the voice frequency range or at least in'a
range- which is‘ suitable for transmission over
7'
'
proceeds;
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_
control relays 1LHS,_RHS and 'DS, and an indi
of a system for communicating by code between
a- controlo?'ice and, a plurality of’remotestations;
Other objects, features and purposes of‘my
invention will ‘he pointed out as the description
,
three»selector-‘relays-Rl, R2 and R3,_ three signal
Another’ object of my-invention is the provision
existing telephone‘ circuits.
_.
‘ The apparatus provided at each-1 station includes
mitted at times over existing railroad" com-mum'
cation circuits without interferingmateriallywith
‘
"In-its'speci?c embodiment; asshown, the system '
current from“ a! tuned’ circuit comprising a coil
-" ; l2 and a condenser Ch. ’ ‘Each-such tunedj circuit
is adapted to- pass su?i'cient current to energize
the» associated relay only‘ when supplied ‘with
current of‘ a particular ‘frequency received over
'
I shall describe one form of apparatus ‘em-‘
the‘ line-wires
andYZ. In the system as shown,
bodying my invention, and shall ‘then. point ‘out ‘-‘ the control of ten- stations 'is-contemplatedg, and a
the novel features thereof'in' claims.
band of3 ten- frequencies ,?- to fill1 is used, ?ve
Referring to the accompanying drawing, the
of'whi’ch; namely, the frequencies ft to‘ ii, ‘are
reference" characters Y and‘ Z‘ designate a pair. of
line wires which ‘it is to be understood. provide
a telephone circuit extending, from ,a control
o?ice at which the apparatus atthe left of the
employed to select the-stations;
1 etc: indicating the frequency to- which each tuned
drawing is located, through aplurality of stations
situated‘ at spaced points alonga stretchffof. raiL'
way at each of which stations a,’ pair'of manual
block signals LH and RH islocatedl as indicated
by the trackv diagram, eachstation beingv provided
with apparatus similar to that. shown at the
right of‘ the drawing, having aiconnection to the
line wires Y and Z asshown. It may be- assumed
that, the stretch is not, provided; with. track , ‘
circuits except for a short detector section ‘B at
each station having a track .itelayy
for: the
.
In; the-drawing,‘ the reference» characters’ fl, f2‘,
circuit isresponsive; are;
adjacent the cir
cuit: ‘the circuit for relayiR3‘, for example; at, the
station shown; being selectively responsive to' the
freuuency?i.v
'
‘
‘
a
'
p'
The ‘relays-'R‘Iiand Rzare direct current relays
ofthe biased polartype which" respond selectively
to the steady‘ component of the current supplied
to the line wires 'Y_ and Z, a reactor 13 being in
terposed! in’ the line connections, relay- RI’ re
spending only when linewire Y positive'and
relay' 1R2" only’ when line wire- Y is‘ negative; with
respect t'o-l'ine wirejZ. At. each of; five stations;
relay‘ vR31 is arranged to respond to a diiierent
control of-the-signalsand for'indicating theimove
one volF-the frequencies flf to 15'» provided relay R1
ments ofv trains past the stationsyand that train
movements through the stretch are'governedl prii» 55‘ is: picked up; the line connection» for the timed
2,396,184
circuits including contact a of relay RI as shown.
At each of the remaining ?ve stations, relay R3
RHS are both in their released positions, an im~
pulse of current of a selected frequency in the
is responsive to a di?erent one of the frequencies
band fI—fI0 will be supplied to the line wires
fl to f5 provided relay R2 is picked up, its tuned
over back contacts e of relays LHS and RHS,
circuit being adjustably connected to contact a 5 front contacts b and c of relay LI, back contacts
of relay R2, and it follows therefore that the re
b of relays RI and R2, coil I5 and condenser C4,
lay R3 at any one of the ten stations may be se
the impulse terminating with the release of relay
lectively energized by a single impulse of pulsat
LI, which relay is slow acting. Relay LHS or
ing current having one of two polarities and one
RHS’ is released automatically following the re
of ?ve frequencies.
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‘
‘
'
10 lease of relay TR by a train, and since relays LHS
Each relay R3 is provided with a stick circuit
and RHS are slow to release, as shown, relay LI
extending from the positive terminal B of a local
becomes energized over a circuit closed momen
source of direct currentat the station over con
tarily which extends from terminal B at back
tact c of the relay RI or R2 which controls its
contact a of relay TR, over front contact d of re
pick-up circuit, as indicated diagrammatically on
lay LHS or RHS through relay LI to terminal C
the drawing, over the front contact a andlower
and the indication impulse will be transmitted
winding of relay R3 to the negative terminal C
during the release period of relay LI following
of the local source. It follows that relay R3 at a
the release of relay LHS or RHS.
selected station may be held picked up, along
It will ‘be seen that since back contacts 11 of
with relay RI or R2, after the alternating current 20 both
line relays RI and R2 are included in the
impulse is terminated, provided direct current
continues to be supplied to the line. Under these
circumstances the tuned circuits for relays DS,
LHS and RHS, which are responsive to alternat
ing currents of frequencies f6, fl and f8, respec
tively, in the same manner as relay R3, are con
nected to the line over contact a of relay RI or
R2 and contact b of relay R3, and if a second
impulse of frequency f6, fl or 18 is supplied to
the line, relay DS, LHS or RHS may be ener
gized, while if a second impulse of frequency fl
or f8 followed by a third impulse of frequency 16
is supplied to the line, relay LHS or RHS may be
energized and relay DS in addition Each of the
relays LHS and RHS is provided with a stick
circuit including its own front contact a, a back
circuit for transmitting the indication impulse,
its transmission cannot occur when the line is in
use for transmitting control impulses to any of
the ten stations.
At the control office, the indication receiving
apparatus includes a set of ten indication relays
KI ‘to KID, of which but three are shown, each
' controlled over a tuned circuit similar to that
provided for the station relays but tuned to a
30 different one of the ten‘frequencies II to II II. Re
lay KI, having its circuit tuned to the frequency
it, responds vto the indication impulse received
from the station shown and is then held energized
overa stick circuit until manually released, light
ing a lamp E I to indicate that the signals LH and
RH at the corresponding station stand at stop.
The office transmitting apparatus includes ten
the track relay TR of the detector track section
sets of manually operable selecting contacts, con
T, consequently if either relay RHS or LHS is
trolled by a series of push buttons PS, for select
energized it may be released manually by opera 40 ing the stations, of which for simplicity but three
tion of relay R3, or automatically by a train en
are shown, namely PSI, PS2 and PSII]; ?ve sets
tering section T. Relay DS has a stick circuit
of manually operable control contacts, controlled
including its own front contact a and front con?
by another series of push buttons PFI to PF5,
tact c of relay LHS or RHS and consequently will
inclusive, for governing the signal control relays
be released along with relay LHS or RHS, if en 45 at the selected_station; a set of ?ve relays PC,
ergized. Relays LHS and DS jointly control the
DR, OR, L andLP for governing the transmis
lamps R, Y and G for signal LH, and relays RHS
sion .of the impulses, and an oscillator including
and DS similarly control those for signal RI-l in
the electron tube VT for generating the alternat
a well-known manner which may be readily as
ing current of the desired frequencies.
certained from the drawing.
50
The operation of contact a of any of the push
contact 0 of relay R3 and a front contact a of
The station apparatus also includes a source of
buttons PS opens the stick circuit for the asso
alternating current of a particular frequency in
ciated indication relay K, and closes a circuit for
the band of frequencies f I to 1‘ I0, which source as
' energizing relay PC, which relay is of the polar
shown may be understood to be an electron tube
stick type and serves as a pole changer to govern
oscillator OSC similar to the one including the 55 the polarity of the direct current supplied to the
tube VT at the office as hereinafter described.
line from a local source having the terminals B
The output circuit of oscillator OSC is adapted to
and C, as shown. It is to be understood that the
be connected to the line wires Y and Z, at times,
operation of any one of the buttons PI to P5 ener
in response to the operation of relay LI, to indi
gizes the upper winding of relay PC to cause it
cate that relays LHS and RHS are released and 60 to operate its contacts a and b to the left as
that the signals are consequently at stop. When
shown to render'the relays RI responsive, while
relays RI or R2, R3 and D3 are operated, relay
the operation of any one of the buttons P6‘ to
LHS or RHS will be released by relay R3, if ener
PI Il energizes the lower winding of relay PC to
gized, and relay LI picks up over the circuit ex
cause it to operate its contacts to the right, to
tending from terminal B at contact 0 of relay
gender the relays R2 responsive to the steady
uI or R2, front contact a of relay R3, front con
component of the line current. The opening of
tact d of relay DS, back contacts (1 of relays LHS
contact
21 of any of the buttons PS disconnects
and RHS through relay LI to terminal C, and is
the
circuits
controlling the indication relays KI
held energized over the stick circuit including
to KID from the line, rendering these relays non
its own front contact a, and extending to termi~ 70 responsive to the control impulses. The closing
nal B at contact 0 of relay RI or R2. When re
of the contact 0 of any ‘of the buttons PS com
lay LI is picked up by a control impulse in this
pletes a connection from the line wires Y and
manner, its energizing circuit is opened as soon
Z to the output coil I6 for the oscillator VT,
as the line becomes free, as indicated by the re
through
a recti?er I8 and a condenser C5, while
lease of relay RI or R2 and if relays LHS and
the‘closingv of contact d of the operated‘button
r‘
3
aaearac
PS; completes a; tunedi circuit: including? coil: l1
and: condenser (it for: controlling the frequency
generated by the; electron tube VT; and delivered
tow the line by. coil: to.‘ Contacts: dot: buttons.
s-ivezindicatlnn, whileBEt andlmcon~
troli relaysv LHSI
respectivelytand: relax
DS in addition, to- cause the selected‘signal:t'lrv
mdi‘cate proceed.
' 'I j
PSt- toPSliI are each connected to a. different. tap (‘In relay
Assuming:
OR willthat
be shunted
button. PF-t
by the
is new
closinguo?the‘
on coil [1: to cause the: generation. oi'ja, different
one of theirequenciesifl to f5-,._ respectively, but
tons PS6: to PSI 0: being similarly‘ connected to
cause. thee generation , of the same frequencies;
Hayingzthusdescribed the various components
or the: system of: my invention, I shall. now ex
plain: its mode ofv operation, assuming ?rst that"
with the. apparatus as shown, the operator de-i
push button contact.’ 0 and; will; release; opening
its
trolled
contact
by. bthe":
in buttons
the circuit
PS6!
fortocondenser
PSlill‘; andi'com
GI
pleting attuned ‘circuit- atrits baclc contacttcxfronr
the upper terminaliof-coil' t1’, condensencii front
contact 11' of; relay: L.’ and: contact; a: ofi button:
PF I! , to: the terminal‘ of coil li‘li marked ‘IF, cans»
sires‘ to obtain a recall indication from the sta—
i'ng‘ tube _V~T to- deliver current: of frequencwf?td
tion shown to verify: therfactthat thesignals are
at2stop; Hewill ?rst operate buttonv PSI, releas
erg-izeslrelay‘ Ll-i at the‘ selected station. I Thezrez- ‘
the 1 line to energize relay DSI, which:
turne en;
ing relayKl: and thereby cancelling the existing
indication displayed by lamp Eli, and operating
lease of? relay ORi- deenergizes relay
which; re~
leases after a brief? period-to terminatestheime
pick up thedetector relay DR, provided the os
pulse ofv frequency fl to energize“ relay'reKlli and‘
pulse, releasing relay» DSL, Relay- ]; deenergiizea
relay PC‘rto normal, as shown. The oscillator
tube VT will'be set.‘ into operation to supply cur- 20 relay LP which- releasesafterasecondi briefiperll
rent‘- to: the line wires of frequency fl over the
steady-"line
od, in’ turn current
releasing:thereby
relay DRY
‘ releasing»
tointerruptl
relay‘v Rf,
connection to coil I8 including contact cv of but
The
release»
of‘
relay
LP’
extinguishes
lamp-GEE’
ton- PSI and recti?er I81. Contacts» d of relays
indicating the return o?the con-trot» apparatusito
RI and- R2 at each station are now‘v open and‘ the ,
alternating current delivered to- the line is prin 25 normal, whereupon button PF? may‘ be‘ released,
while' the release of relay Rt deenergizesj relays
cipally dueto thecapacity between linewires Y
R3
and Li and‘initiates the-retu-m indication inr
and
This, however, is' of a value su?icient to
cillatordelivers theproper- voltage and its con
light the lampEl.
nections to? the line wires are intact so as-to in
clude the» line capacity in its output circuit.
When relayDRIpicks up, unidirectional current is
suppliedv to’ the‘ line- circuit including the relays
El- and R2‘, over-the‘ connection from terminalsv
ton
Assuming
P-S-l assabove
next‘ that
described
the operator'presses
and then after‘ree
leasingibutton PSI presses button-PFZ'or P‘Fil; are
impulse" of" frequency IT or I81 will be delivered‘
to the line for’ the duration of= the release period‘
relays illustrated by the relays L and LP which
duration of the release-period of relay'L‘, to op»
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‘
‘
‘
B: andC-at contacts a and b of relay PC, contacts I : of relay'L to operate relayLHS or'RHS; which‘re
lay will then'be‘ held energized over itsstick' circuit‘
b» and c' of‘ relay DR through the direct current
includingL front contact a of'relayTR', butrelayi
relay OR and coil [9 to the line wires Y and Z,
Ll will not be operated and no’ indication imé
thereby picking up relay'OR and also'the relays
pulse will be transmitted, consequentlylamp-Ell‘
Rt‘ at all" stations to‘ open their contacts ‘him the
will remain dark;
,
indication circuits, and to close- their contacts a, so
If- button" PF4 or PF51 is operated'in; place of='
that relay R3-- at the selected station also picks
button PFZ or PF3, an impulse of’frequency?‘ or‘
up; The closing of contact a of relay OR ‘com
~J‘8 will likewise bedeli-veredto the'line- fen-the
plet'es a- circuit for energizing’a chain of' timing
erate relay LHS or-RHS, but in this~instance=a=
pick up successively, the closing" of contact a of
tuned circuit will be completed upon the-release
of relay L' including coil: I1, condenser 02} back‘
contacts 0 and; b of relays 0R1 and'~L; frontfcons»
tact cv of relay LP‘ and contact‘Z'rof-‘the-operatedZ
relay LP lighting a' control lampCE and corn- ‘
pl‘eting' a- local stick circuit for relay DR; It'will
becnote‘d that the tuned circuit including coil l1
and‘ condenser C‘! which was completedv initially
over back'contact b of relay-1GP» is now“ completed
over front-contact‘ b of‘ relay OR, and that con-_
tact‘ e of relay DR provides a connection from
coil" l‘B-tov the line in parallel with contacts 0 of
button, so that‘ an" impulse of frequencyft‘
be delivered to the-line for the duration otitllev
release period of- relay LP to operate relay DS;
which relay will then be held energized ovenits
buttons PS‘. i. It will be also notedv that if two of
the buttons PS‘ which control di?erent frequen- -
cies'are inadvertently operated at the same time,
a portion of; the coil [1 will be short circuited by
their" contacts at to’ prevent the generation of \
alternating’ current by the tube VT, the selection
of more than one relay R3? at a time being thereby 60
prevented;
,
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When‘ lamp CE‘ becomes" lighted", the operated"
button P'Sl may be released. The opening of
its‘contact‘ d terminates the delivery of the alter
nating‘current‘ component‘ of the" impulse, relays '
OR, L; LP, DR at‘t'he oflice, and relays RI and‘
R3" at the selected" station remaining energized‘
due? to" the flow of unidirectional current in the"
line circuit.
The operatorwi'll now pressv one of the buttons
PF! to 2E5‘. Button PF! controls relayDS only;
for the purpose of‘ initiating a‘ return indication
when the signals. are" at stop. Buttons PFZ and
PF3‘ control’v relays‘ IJHS‘ andv RL'HS, respectively,‘
to, cause- the‘selccted 'si‘gna'rto display itsrpermis is
stick circuit including- ,contact' c‘ of‘ relay- 133$
or RHS. In this‘ case relay Lt isnoti operatedS
because its circuit is opened‘ at back’contact-d‘
of; relay LHS orR-I-IS.prior to the'closing'of front‘
contact 12‘ of relay’DS, and therefore no‘imzli'cati‘onv
impulse is transmittedand lamp‘ E‘I remained‘arl'r;
It will be seen that relay Ll is“ operated by‘relay“
DS to? initiate a return indication impulseonlys
when the operation of" relay DS‘ i‘s-jd'ue‘to” the‘
operation of button PM, as herei-nbefore dew
scribed.
‘
'
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’
'
It will also be seen that after the signal'IlH? or
RH‘ has been cleared, it may'be'put' manuallytoi
stop and the return‘ indication initiated’ to/li’ght‘
lamp El by pressing buttons PSI and‘PFl, or‘ it
will‘ be put automatically to- stop thev lamp El‘
lighted, due to the release of the trackrelayTR
when a train governed‘ by the signal enters‘ sec
tion T, in which case the signal‘ will remain- at
stop, due to the release of-thecstick‘ rel‘ayLHSbr
RHSiaftersection T is vacated;
, v
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,
-
Although I have herein shown‘ and‘d‘escrlbli'i'lx
4
‘2,396,134
only one form of remote control system embody‘
wires, corresponding circuit elements at di?erent
ing my invention, it is understood that various I
stations being tuned to different frequencies‘, a
changes and modi?cations may be made therein
within the scope of the appended claims without
departing from the spirit and scope of my in
holding circuit for each second line relay includ
vention.
,
r
'
Having thus described my invention, what I
claim is:
1. In a remote control system, an omce and a
plurality of stations connected by line wires, two
ing a front contact of the associated ?rst line
relay, a plurality of control relays at each sta
tion having holding circuits controlled locally
and having energizing circuits including front
contacts of both line relays at that station and
also including tuned circuit elements rendering
each control relay at a station selectively respon
line relays at each station, one of which is re
sive to alternating current in the line wires of
sponsive to direct current in said line wires and
a frequency different from that to which the
the other to alternating current of a distinctive
other relays at such station are responsive, and
frequency, said alternating current line relay be
control means at the omce for supplying current
ing connected to the line wires over a front con 15 of said distinctive character to the line wires for
' tact of the direct current line relay through tuned
a brief period to energize the ?rst line relay at
circuit elements responsive to a frequency to
each station and for supplying a series of im
which the corresponding circuit elements at other
pulses of alternating current, each of a different
stations are non-responsiva'a holding circuit for
frequency, to the line wires to selectively and
each alternating current line relay including front 20 successively energize the second line relay and
contacts of both line relays at that station, a plu
one or more of the control relays at a selected
rality of control relays at each station having
station during such period.
holding circuits controlled locally and having en
4. In a remote control system, an ethos and a
ergizing circuits includingfront contacts of both
station connected by line wires, a line relay at
line, relays at that static-n and also including 25 the station, a selective communication channel
tuned circuit elements rendering said control re
for controlling the line relay including a source
lays selectively responsive to alternating currents
of alternating current of controllable frequency
of different frequencies in said line circuit, and
at the o?ice, said line wires, and tuned circuit
control means at the of?ce for supplying direct
elements resonant to a particular frequency,
current to the line wires for a brief period and for
manually operable selecting means at the office
supplying two impulses of alternating current of
including a relay for establishing said channel
selected frequencies to the line wires successively
and means for supplying alternating current
during such period to selectively energize a par
thereto of said frequency to energize the line
ticular control relay at a selected station.
relay, circuit means for maintaining both the
2,. In a remote control system, an of?ce and a
oflice relay and the station line relay energized
plurality of stations connected by line wires, said
after the manually operable means is released
stations being arranged in two groups, a polarized
and the delivery of alternating current to said
relay at each station responsive to steady current
channel is thereby interrupted, a plurality of
in said- line wires, the polarized relays at the sta
controlrelays at said station, control channels
tions of one group being responsive to line cur 4 o for selectively energizing said control relays by
rent of normal polarity and those at the stations
alternating current from said source, following
of the other group to line current of reverse po
the release of said manually operable selecting
larity, another line relay at each static-n respon
means, each such channel including a front con
sive to alternating current of a distinctive fre
tact of said line relay and tuned circuit elements
quency and connected to the line wires over a “3d rendering each control relay responsive to cur
front contact of the associated polarized relay
rent of a frequency different from those to which
through tuned circuit elements responsive to a
the line relay or the other control relays are re
frequency to which the corresponding circuit ele
sponsive, manually operable control means at the
ments at other stations of the same group are not
office effective when operated to release said o?ice
responsive, a holding circuit for each such alter 50 relay, and timing means responsive to the release
nating current line relay including a front con
of said onice relay effective to supply an impulse
tact of the associated polarized line relay, a plu
of alternating current of a particular frequency
rality of control relays at each station having
selected by said control means to said control
holding circuits controlled locally and having en
channels to selectively energize a particular con—
ergizing circuits including front contacts of both‘ : trol relay, and to then release said line relay.
line relays at that station and also including
5. In a remote control system, an o?ice and a
tuned circuit elements rendering each control re
station connected by line wires, a line relay at
lay at a station selectively responsive to alternat
the station, a selective communication channel
ing current in the line wires of a frequency dif
for controlling the line relay including a source
ferent from that to which the other relays at such‘ I of alternating current of controllable frequency
station are responsive, and control means at the
at the office, said line wires, and tuned circuit ele
office for supplying steady current of a selected
ments resonant to a particular frequency, manu
polarity to the line wires for a brief period and
ally operable selecting means at the o?ice includ
for supplying two impulses of alternating current
ing a relay for establishing said channel and
of selected frequencies to the line wires during
means for supplying alternating current thereto
such period to selectively energize a particular
of said frequency to energize the line relay, cir
control relay at a selected station.
cuit means for maintaining both the office relay
3. In a remote control system, an office and
and the station line relay locally energized after
a plurality of stations connected by line wires,
the manually operable means is released and the
a ?rst line relay at each station selectively re 70 delivery of alternating current to said channel is
sponsive to current of a distinctive character, a
thereby interrupted, a plurality of control relays
second line relay at each station connected to the
at said station, control channels for selectively
line wires over tuned circuit elements to render
energizing said control relays by alternating cur
such relay selectively responsive to alternating
rent from said source, following the release of said
current of a ‘particular frequency in said line 75 manually operable selecting means, each such‘
, 5
2,896,134
to a different frequency of ‘current from said
source, means responsive to the operation of each
channel including a ‘front contact of said line
relay and tuned circuit elements rendering each
set of selecting contacts for preparing said chan
nels for communication between the office and
control relay responsive to current of a frequency ,
different from those to which the line relay or
the corresponding station, and for closing a cir
cuit for said timing relay, a plurality of sets of
the other control relays are responsive, manually
operable control means at the o?ice effective
manually operable control contacts at the office,
when operated to release said oiiice relay, and
including one set for each control relay at a sta
tion, for controlling the frequency of the current
supplied by said‘ source, and means responsive to
the operation of each set of control contacts for
timing means responsive to the release of said
o?ice relay effective to supply successive impulses
of alternating current of different frequencies
selected by said control means to said control
opening the circuit for said timing relay and for
rendering said source effective during the release
period thereof to supply current from said source
to the prepared channels of a frequency to which
channels to energize a selected plurality of said .
control relays, and to then release said line relay.
6. In a remote control system, an o?ice and a
- station ‘connected by line wires, a line relay and a
the corresponding control relay is responsive.
control relay at the station, selective communi
cation channels for controlling said relays each
8. In a remote control system, an office and a
plurality of stations connected by line wires, a
including a source of alternating current of con
trollable frequency at the office, said line wires,
and tuned circuit elements resonant to different
frequencies, the channel for-the control relay
plurality of communication channels including
20 said line wires and a source of alternating current
of controllable frequency, a plurality of sets of
manually operable selecting contacts at the ofllce,
including
one set for each station, a‘chain of
local holding circuit for thelcontrol relay includ
timing relays at the office, a plurality of control
ing a back contact of the line relay, manually
operable means at the o?ice for establishing said ' . relays at each station, each responsive selectively
to a different frequency of current from said
channels one at a time for brief periods and for
source, means responsive to the operation of each
supplying alternating current thereto to which
set'of selecting contacts for preparing said chan
said relays are responsive, means responsive to
nels for communication between the o?ice and the
one operation of said'manually operable means
corresponding station and for energizing the re
for supplying to said channels alternating cur’.
lays of said chain, a plurality of sets of manually
rents of-both frequenciesto energize the line re
operable control contacts at the oilice, including
lay and the control relay, and means responsive
one set for each control relay at a station,rfc-r
to another operation of said manually operable
controlling the frequency of the current supplied
means for supplying to said channels alternat
ing currents of only one frequency to energize the , ,= by said source, and means responsive to the op
eration of each set of control contacts for re
line relay only and thereby release said control
leasing said timing relays one at a time in order,
and means effective during the release period of
7. In a remote control system, an office and a
said timing relays for supplying current from
plurality of stations connected by line wires, a
plurality of communication channels including 40 said source to di?erent ones of said prepared
channels one at a time to successively energize
said line wires and a source. of alternating current
a plurality of said control relays by currents of
of controllable frequency, a plurality of sets of
including a front contact of the line relay; a ,
relay.
‘
.
manually operable selecting contacts at the o?ice,
including one set for each station, a slow release
timing relay at the office, a plurality of control 45
relays at each station each responsive selectively
different frequencies, dependent upon which set
of control contacts has been operated.
ANDREW J. SORENSEN.
'