Year: 1896

page_text: Date claimed for Patent under Sect. 103 of Act,
being date of first Foreign Application (in 27th Mar., 1896
United States of America),
Date of Application (in United Kingdom), 27th Oct., 1896
Coniplete Specification. Left, 27th Oct., 1896-Accepted, 20th Mar., 1897
COMPLETE SPECIFICATION.
I, THOMAS BULLITT DIXON of Henderson in the County of Henderson and
State of Kentucky, United States of America, Gentleman, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be.
particularly described and ascertained in and by the following statement :-
My invention relates generally to polar instruments, such as polar relays,
employed in systems of signaling, such as telegraphy, and operated by reversals of
current or polarity in the circuits to which they are connected; and my invention
relates particularly to means for preventing such polar instruments from being
influenced by false currents in the line.
In systems of signaling which operate by the reversal or change of polarity of
the circuit there sometimes occur times when the current in the circuit is weak or
ceases entirely, and it is well known that at such times of no current the polar
instruments are liable to be falsely operated by false currents, such as may be
induced by currents in neighboring lines, thus giving rise to false operations of the
polar instruments.
My present invention is particularly applicable to the system of multiple
telegraphy described in an Application for a Patent filed by me on January 28,
1896, No. 2043. In this system there are employed one or more current-varying
transmitting instruments arranged to vary the current strength in the line or to
stop the flow of current through the line altogether and a current-reversing
or pole-changing transmitter arranged to reverse the current in the line,
together with suitable receiving instruments which are operated by the variations
in current strength or direction produced by said transmitting instruments. In
this system means are provided, when the pole-changing transmitter is operated
at a time when no current is flowing through the line, for producing a brief
pulsation of current at the instant when the polarity of the line is reversed, so
that by this means the receiving instrument corresponding to the pole-changing
transmitter may be operated; but in this system there is some liability that
during the period of no current in the line false induced currents set up in the
line by induction from neighboring lines may cause false operation or mutilation of
the signals of the polar receiving instrument.
My invention consists in the means whereby false operation of polar instruments
by false or induced currents, weaker or of shorter duration than the current by
which the polar instruments are normally operated, may be prevented.
The objects of my present invention are to provide means for so controlling.

page_text: polar instruments that they may not be operated or in any manner affected by false
currents in the lines, and to make the means for preventing such false operation as
simple as possible. These objects are attained in the invention herein described
and illustrated in the drawings which accompany and form a part of this
application, in which the same reference letters and numerals indicate the same or
corresponding parts, and in which :-
Figure is a diagram illustrating the application of the polar instrument
operating in accordance with my invention to a multiple-telegraph system, the
particular system illustrated being that described in my above mentioned patent.
The figure shows, diagrammatically, telegraphic circuits for transmitting two
messages simultaneously in one direction, one by variation of current strength in
the line and the other by reversal of polarity in the line. Figs. 2 and 3 are
similar diagrams of the polar instruments and connections, showing different
circuits for controlling the instrument.
In the drawings, A is the transmitting station of the telegraph line, and B the
receiving station, the two stations being connected by a line wire L.
T is the pole-changing transmitter, and T' the current-varying transmitter, both
of which are electrically operated and are controlled by finger-keys K and K',
respectively, in the ordinary manuer.
6 is the line-battery, which transmitter T¹ is arranged to throw into and out of
the line-circuit, and R is the usual resistance for maintaining the resistance of the
line constant when battery b is cut out of the line-circuit. Transmitter T is
arranged when operated to reverse the polarity of the line.
At station B, 1 is the polar relay responding to transmitter T. 2 is the line
neutral relay responding to transmitter T. 3 is a local polar relay controlling
and controlled by the line polar relay 1 in the manner to be hereinafter
described.
4 is a dead-beat relay, controlled by line neutral relay 2, in the manner described
in my said Application for a Patent, No. 2043 of 1896.
S is the sounder or receiving instrument operated by polar relay 1, and S' a
sounder operated by neutral relay 2. Polar relay 1 is wound with three
independent series of coils cl cc 11, termed "main," "secondary," and "tertiary".
coils, respectively.
5 and 6 are local batteries, each connected to one contact-point of polar relay 1,
the negative pole of battery 5 being connected to one contact-point of relay 1 and
the positive pole of battery 6 being connected to the opposite contact-point of
relay 1 through the sounder S.
.7 and 8 are rheostats in the circuits of batteries 5 and 6. Their function is to
equalize and regulate the currents of the two batteries.
9 and 10 are local batteries connected to opposite contact-points of local polar
relay 3, the negative pole of battery 9 and the positive pole of battery 10 being
connected each to one of these contact-points.
In the drawings the instruments and circuits are shown in normal positions.
The normal direction of current is from E', where the line is grounded at station B,
through main coils c¹ of relay 1, relay 2, and the line conductor L, through
lever 12 and contact-point 13 of transmitter, T, conductor 14, contact-tongue 15 of
transmitter T', contact-levers 16 and 17, conductor 18, battery b, conductor 19,
contact-points 20 and 21 of transmitter T, and conductor 22 to earth at E. The
normal direction of current in the line is indicated by an arrow a at station B.
The effect of the operation of the current-varying transmitter T', due to the
depression of key K, is to throw battery bout of circuit, so as to stop the
flow of current in the line, the line-circuit, however, remaining complete through
resistance R. The effect of the operation of pole-changing transmitter T is to
reverse the line polarity, and if this takes place at a time when battery b is out of
the line the operation of transmitter T, due to the depression of key K, breaks the
circuit of magnet 23 of transmitter T', causing lever 16 to fall and make contact
with tongue 15, thus throwing. battery 6 into circuit, and an instant thereafter

page_text: causing the contact-lever 17 to break contact with lever 16, thus again throwing
battery bout of circuit, the effect of the fall of lever 16 being to produce in the
line conductor La brief pulsation of current, which passes through the line an
instant after the contact-points of transmitter T reverse the polarity of the line.
This operation of the transmitting instrument is more fully described in my said
Application for a Patent, No. 2043 of 1896.
The effect of the reversal of polarity in the line, as above described, is to move
the armature of relay 1 from the left-hand contact-point, as shown in the drawings,
to the right-hand contact-point. When key K is released, a corresponding reversal
of line polarity takes place, together with a second production of a pulsatory
current in the line, if transmitter key K' is still depressed, and the armature of
relay 1 is again deflected, this time against its left-hand contact-point.
The current of battery 5, when the armature of relay 1 is in normal position,
passes through rheostat 7, conductor 24, secondary coils a", conductor 25, the coils
of local polar relay 3, conductor 26, and the armature of relay I, to the left-hand
contact-point of the polar relay, and back to battery 5. When the armature of
relay 1 is deflected to the right, the cirenit of battery 5 is broken, and the circuit
of battery 6 is completed as follows: from the positive pole of battery 6 through
conductor 27, sounder S, conductor 28, to the right contact-point of relay 1, through
the armature of relay 1, conductor 26, coils of relay 3, conductor 25, coils ell of
relay 1, conductor 24, rheostat 8, and so back to battery. This current, as will be
noted, passes through the coils of relays 1 and 3 in the reverse direction to the
current of battery 5. The current of battery 5 passes through the coils et in the
same direction that the line-current passes through the coils c when the direction
of current in the line is normal-that is, the direction indicated by the arrow a-
and the current of battery 6 passes through the cails el only when the line-current
has been reversed. Therefore the direction of the current in secondary coils cll is
always the same as that of the current in the main coils c', or of the last current
which flowed through coils el in ease the main current is interrupted. Therefore
the secondary coils e tend to hold the armature in the position in which it is
placed by the main coils e. The effect of the substitation of battery 6 for
battery 5 upon the local circuits of the polar receiving instruments therefore is
but to reverse the direction of the current in the circuit of the secondary
coils but this reversal moves the armature of relay 3 from its left-hand
contact-point to its right-hand contact-point. In the normal position of the
armature of relay 3 a current passes from the positive pole of battery 9 through
conductor 29, tertiary coils e, conductor 30, and the armature, and the left-hand
contact-point of relay 3 back to battery. The direction of current of battery 9
through the coils el i is the reverse therefore of that of battery 5 through coils a",
and the influence of coils cupon the armature of relay 1 is opposed to that of
coils ; but battery 9 is weaker than battery 5. Therefore the magnetizing
influence of coils upon the armature is not entirely neutralized by that of
coils When the armature of relay 3 is deflected to the right, the current
of battery 10 passes through the coils in the reverse direction to that of
the current of battery 9; but the armature of relay 3 is only deflected to the
right when the armature of relay 1 is also deflected to the right. Therefore when
the armatures of these relays are to the right the influence of coils upon
the armature of relay 1 is still opposed to that of coils e", but does not completely
neutralize the same, since battery 10 is weaker than battery 6.
The effect of the substitution of battery 10 for battery 9, as with the sub-
stitution of battery 6 for battery 5, is merely to reverse the direction of the
current in the circuit.
To simplify the explanation of the operation of this invention, definite values
of current strength will be as follows: batteries b, 5, and 6, one hundre! units
each, and batteries 9 and 10 fifty units each, it being assumed that the coils e, e",
and are so constructed and so placed that if their currents were of equal
strength they would affect the armatare equally. It is obvious that the same

page_text: effect on the armature may be obtained by using batteries of equal strength and
by employing coils c', c", and "of different length or resistance, or by placing
the coils at different distances from the armature, so as to affect it unequally.
With the values of current strength assumed there exists normally in the coils
of the relay 1 a total influence upon the armature of relay 1 equal to that of
the current of battery b, one hundred units, plus that of battery 5, one hundred
units, minus that of battery 9, fifty units-in all, one hundred and fifty units. If
now key K is depressed, thus reversing the polarity of the line and causing the
line-current to flow through the coils c¹ of relay 1 in the opposite direction to
that indicated by the arrow a, then the influence upon the armature of the main
coils c¹, one hundred units strength, is added to that of the tertiary coils c",
fifty units strength, thus overbalancing the influence of secondary coils c", one
hundred units, by a margin of fifty units, causing the armature of relay 1 to be
deflected to the right. The instant the armature leaves its left-hand contact-point
the circuit of secondary coils el is broken, so that the full current strength of
coils and tends to move the armature of relay 1 to the right, and even if
battery should be thrown out of circuit at the instant when the armature of
relay 1 is moving to the right, as by the breaking of contact between tongue 15
and lever 16 of transmitter T¹, or between levers 16 and 17, there would still
remain the influence of coils c¹ 11 to move the armature of relay 1 to the right.
The instant the armature of relay 1 reaches its right-hand contact the circuit of
coils is completed, the current being from battery 6 and in the opposite
direction to the former current and in a direction parallel to the new direction
of current of battery b through coils c', while the armature of relay 3 is deflected
to the right, throwing battery 9 out of the circuit of tertiary coils 1" and
throwing battery 10 into the circuit of coils el ", thus reversing the direction of
the current in the tertiary coils. When key K is released, transmitter T restores the
line to its normal polarity and a similar but reverse operation takes place,
the armature of relay 1 being moved to the left by the combined influence of
coils and c", opposed to the influence of coils c, the influence of coils c
ceasing, however, the instant the armature of relay 1 leaves its right-hand contact-
point.
The operation of the receiving instruments is the same as above described when
key K is depressed or released while key K¹ is depressed, battery b, although
out of circuit at the time when key K begins to be depressed or released, being
thrown into the line-circuit momentarily by the operation of the contact-points
of transmitter T at the instant of or immediately after the reversal of line
polarity by transmitter T and being kept in the line long enough to at least
start the armature of relay 1 to moving. It will be seen, therefore, that for
the operation of the polar receiving instruments it is only necessary that the
current of battery b shall continue for a period long enough to permit the armature
of relay 1 to break contact with the stop against which it is resting when the
reversal of line polarity takes place. The instant the armature has left this stop
the circuit of the secondary coils c" is broken, and after that the armature is or
may be moved by the tertiary coils c¹ alone. This is important, as it is this
feature which makes it possible to operate the receiving instruments by a pulsatory
current over a long line. If transmitter key K' is already depressed at the time
when key K is depressed, so that battery is out of the line, then battery bis
thrown into the line for a.brief instant by the operation of levers 16 and 17 and
magnet 23 at the instant when the reversal of line polarity takes place, and the
current flowing through the line in the brief instant of reversal of line polarity
has but to be continued for a sufficient period of time to permit the armature of
relay to break contact with the contact-point against which it is resting at the
instant of reversal of line polarity, after which the movement of the armature
continues, owing to the influence of the tertiary coils e". It is therefore possible
to operate relay I by a very brief pulsatory current, such as will be obtained even
on very long lines.

page_text: It will be observed that at no time when there is no current flowing through the
main coils is the armature of relay 1 free to move. The secondary coils ell, the
influence of which is only partly counteracted by the tertiary coils c, always
act to hold the armature in that extreme position in which it was placed by the
coils when those coils were last energized. False currents induced in the line
conductor by currents in neighboring lines can never have sufficient strength to
overcome the influence of the secondary coils c" on the armature. The influence
of the coils can only be overcome by the coils sufficiently to permit the
armature to move.
The transmitters T and T (shown in the drawings) are arranged to keep the
line-circuit normally closed; but the polar relay 1 and the circuits by which it is
controlled operate equally well in normally open circuits, the relay being as free
from disturbance while the line-batteries are cut out for considerable intervals of
time as when cut out only momentarily.
All of the three sets of magnet-coils of relay 1 need not be wound upon the
same cores. Instead, one or all sets may be wound upon separate cores, all acting
upon the same armature-lever. This is illustrated in Fig. 2, in which the tertiary
coils are wound upon separate cores.
As already pointed out, the batteries 5 and 6 of the secondary coils and the
batteries 9 and 10 of the tertiary coils serve merely as convenient means for
reversing the direction of the current in these coils when the armature of relays 1
and 3 are moved. Instead of using two batteries to effect the reversal of the
current in each of said circuits, other well known circuit-reversing devices may be
used, or the secondary and the tertiary coils, one or both, may be divided and
placed upon opposite sides of the armature, the current being passed through the
coils on one side of the armature when the armature is to be attracted toward that
side, and vice versa. This is illustrated in Figs. 2 and 3, in which the tertiary coils
are so divided. Thus when the armature of relay 3 is against its left-hand contact-
point the current of battery 9 passes through the coils on the right-hand side
of relay 1, and when the armature of relay 3 is against its right-hand contact-point
the current from battery 9 passes through the coils on the left-hand side of
relay 1.
Instead of dividing up the secondary or tertiary coils in the manner shown
in Fig. 2, these coils may be divided in the manner shown in Fig. 3, in which the
magnets of the polar relay 1 are provided with two independent sets of secondary
coils c each similar to the coils c" of Fig. 1. The contact-points of relay 1 are
arranged to send the current of battery 5 through the coils c, when the armature
is against the left-hand contact-point and to send the current of battery 5 through
the coils e, in the opposite direction when the armature is against the right-hand
contact-point. This it will be seen is merely another method of reversing the
polarity of the secondary coils equivalent to the reversal of current accomplished
by the circuits of Fig. 1.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In a polar instrument, the combination, with a polarized armature movably
mounted, and main, secondary, and tertiary magnet-coils each arranged when
energized to tend to deflect the armature in one direction or the other according to
the polarity of said coils, of circuit-controlling devices operated by the movement
of said armature and controlling the circuit of said secondary coils, arranged when
the armature is in either extreme position to cause said circuit to energize said
secondary coils so as to tend to hold the armature in that position, and electrically-
controlled circuit-controlling devices controlled by the circuit of said tertiary
coils and arranged when the armature is in either extreme position to cause said
circuit to energize said tertiary coils to tend to move the armature to the opposite
position, substantially as described.

page_text: 2. In a polar instrument, the combination, with a polarized armature movably
mounted, and main, secondary, and tertiary magnet-coils each arranged when
energized to tend to deflect the armature in one direction or the other according
to the polarity of said coils, the influence of the tertiary coils on said armature
being weaker than that of the main or secondary. coils and the influence of the
secondary coils on said armature being weaker than that of the combined influence
of the main and tertiary coils, of circuit-controlling devices operated by the
movement of said armature and controlling the circuit of said secondary coils.
arranged when the armature is in either extreme position to cause said circuit to
energize said secondary coils to tend to hold the armature in that position, and
electrically-controlled circuit-controlling devices controlled by the circuit of said
secondary coils and controlling the circuit of said tertiary coils and arranged when
the armature is in either extreme position to cause said circuit to energize said
tertiary coils to tend to move the armature to the opposite position, substantially
as described.
3. In a polar instrument, the combination, with a polarized armature movably
mounted, and main, secondary, and tertiary magnet-coils each arranged when
energized to tend to deflect the amature in one direction or the other according to
the polarity of said coils, of circuit-controlling devices operated by the movement
of said armature and controlling the circuit of said secondary coils, arranged when
the armature is in either extreme position to cause said circuit to energize said
secondary coils to tend to hold the armature in that position, electrically-controlled
-circuit-controlling devices controlled by the circuit of said secondary coils and
controlling the circuit of said tertiary coils, and arranged when the armature is
. in either extreme position to cause said circuit to energize said tertiary coils to tend
to move the armature to the opposite position, and means for supplying current to
- said secondary and tertiary coils, arranged to make the strength of the tertiary
.coils less than that of the main or secondary coils and to make the strength of the
secondary coils less than the combined strength of the main and tertiary coils,
substantially as described.
4. In a polar instrument, the combination, with a polarized armature movably
mounted, and main, secondary, and tertiary magnet-coils each arranged when
energized to tend to deflect the armature in one direction or the other according to
the polarity of said coils, of circuit-controlling devices arranged to reverse the
currents in said secondary and tertiary coils successively when the direction of the
current in the main coils is reversed, and to give the secondary coils the same
polarity as the main coils and the tertiary coils the opposite polarity, substantially
..as described.
5. In a polar instrument, the combination, with a polarized armature movably
mounted, and main, secondary, and tertiary magnet-coils each arranged when
energized to tend to deflect the armature in one direction or the other according
to the polarity of said coils, of circuit-controlling devices arranged to reverse the
current in said secondary coils when the direction of the current in the main coils
is reversed and to give said coils the same polarity as the main coils, and a polar
relay, operated by the circuit of said secondary coils and controlling the circuit of
said tertiary coils and arranged to reverse the current in said tertiary coils when
the direction of current in the secondary coils is reversed, and to give the tertiary
coils the opposite polarity to the main coils, substantially as described.
6. In a polar instrument, the combination, with a polarized armature movably
mounted, and main, secondary, and tertiary magnet-coils each arranged to deflect
the armature in one direction or the other according to the polarity of said coils,
of circuit-controlling devices, operated by the said armature and controlling the
circuit of said secondary coils, and arranged to give said secondary coils the same
polarity as the main coils, to deenergize the secondary coils when the said
armature moves, and to reverse the polarity of said secondary coils when the
polarity of the main coils is reversed, and circuit-controlling devices operated by
the circuit of the secondary coils and controlling the circuit of the tertiary coils,

page_text: and arranged to reverse the polarity of the tertiary coils when the polarity of the
secondary coils is reversed, and to give the tertiary coils the opposite polarity to.
the main coils, substantially as described.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.