and Apparatus for Electrical Signalling by Means of Split or Divided Currents, more particularly applicable to Cable Trans- mission.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Method and Apparatus for Electrical Signalling by Means of Split or
Divided Currents, more particularly applicable to Cable Trans-
mission.
I, CHARLES DENTON ABEL, of 28, Southampton Buildings, Chancery Lane, in
the County of London, Chartered Patent Agent, do hereby declare the nature of
this invention (as communicated to me from abroad by La Societe Industrielle
des Telephones (Constructions Electriques, Caoutchoucs Cables) of 25, Rue du
Quatre Septembre, Paris, France, Manufacturers) to be as follows:-
The main feature of the method of electrical transmission which forms the
subject of this invention, consists in the division or splitting up of each signal-
ling current into two waves having contrary direction.
Each signal thus carries in itself the two elements which are indispensable
for charging a cable and for effectually discharging it. This result is obtained
by the combination of an automatic transmitter with a local relay, a trans-
former and a local battery. The transmitter is preferably of the well known
Wheatstone type, already in use on telegraphic lines for transmitting the Morse
code. The transformer is constructed on the principle of the induction coil
arranged with parasite circuits with a view to avoiding extun current and
moderating the pressure of the currents.
The arrangement of the transmitter, relay and transformer may either be such
that at each signal two successive contacts are made, the one conveying a posi-
tive and the other a negative current into the line, or there may be transmitted
at each signal first two consecutive positive currents and then two consecutive
negative currents.
The transformer is constructed with two inducing circuits which are either
connected in series or in parallel, or are separate, according as one or two line
batteries are used, and two induced circuits which may also either be in series
or in parallel, and are connected with the line or.cable. Between these several
circuits there are arranged closed circuits, which may either each consist of a
single wire coil, or a metal sheathing, interposed between the primary and
secondary coils and between the two secondary coils, and also covering the outer
surface of the latter. These closed circuits take a large proportion of the self
induction, and may be termed parasite circuits; they enable the pressure of
the secondary current to be limited, and they entirely absorb the extra current.
Instead of such closed parasite circuits might also be employed a resistance of
any kind, such as a coil, or two electrodes immersed in water, or a condenser, con-
nected in shunt on the secondary circuit.

page_text: There may either be a single such transformer, or there may be two of them,
one connected to each contact or contacts of the relays.
In arranging the apparatus for transmitting a single positive and negative
current for each signal, there are two relays excited by a local battery, each
relay being according to one arrangement connected to one of the primary circuits
including a battery, and having its contact arranged to signal either by opening
or closing the circuit.
When the apparatus is arranged for transmitting two positive and two nega-
tive currents, the armature key of each relay, on being attracted is made to both
break a battery circuit having say a positive current and to close a battery circuit
having a negative current, the connections of the batteries with the primary
circuits of the transformers being such that by this means two consecutive cur-
rents of the same sign are thus produced in the secondary circuit by the one
motion of the armature key, while by the reverse motion two similar consecutive
currents of the opposite sign are produced.
The above described arrangement of transformers with two sets of primary
and secondary circuits may also be employed for producing a positive and nega-
tive current for each signal without the use of relays, by using any known form
of automatic transmitter that will send a direct signalling current.
ABEL & IMRAY,
Agents for the Applicant.
Method and Apparatus for Electrical Signalling by Means of Split or
Divided Currents, more particularly applicable to Cable Trans-
mission.
I, CHARLES DENTON ABEL, of Birkbeck Bank Chambers, Southampton Build-
ings, but formerly of 28, Southampton Buildings, Chancery Lane, in the County
of London, Chartered Patent Agent, do hereby declare the nature of this inven-
tion (as communicated to me from abroad by La Societe Industrielle des Tele-
phones (Constructions Electriques, Caoutchoucs Cables) of 25, Rue du Quatre
Septembre, Paris, France, Manufacturers) and in what manner the same. is to
be performed to be particularly described and ascertained in and by the follow-
ing statement:
-
The main feature of the method of electrical transmission which forms the
subject of this invention, consists in the division or splitting up of each signal-
ling current into two waves having contrary direction.
Each signal thus carries in itself the two elements which are indispensable
for charging a cable and for effectually discharging it. This result is obtained
by the combination of an automatic transmitter with local relay, a transformer
and two local batteries. The transmitter is preferably of the well known
Wheatstone type employed in telegraph lines; and the transformer is on the
principle of the induction coil with parasite circuits to moderate the tension of
the current.
.
The construction and operation of apparatus according to this invention will
be described with reference to the drawings.
Figure 1 is a front view of the transmitter. A communicates with the copper
of the local battery. B communicates with the dot relay and C with the dash
relay. The other ends of the relay coils are connected to the zinc of the local

page_text: "
battery. As relays have long been used for telegraph lines, no claim is made
here except to improvements of these according to this invention. Figures 2, 3,
and 4 shew a relay in detail. It comprises an electro-magnet with flat cone and
coils very close together. The pallet P being thin and of the shape of the end
of the magnet, can vibrate rapidly when successively attracted. It is suspended
from a horizontal axis a a¹ and the currents are carried by the coils bb. The
two contacts D, E are regulated by screws R R¹ and are connected to two bat-
teries so that two successive currents can be sent in the same direction the pur-
pose of which will hereafter be explained. There may be two transformers or
only one, and in respect of these no claim is here made except to the arrangements
by which they are suited for Morse signalling, employing positive currents for
the dots and negative currents for the dashes.
At present in cable telegraphy a double key is used, which receives and sends
the current directly from a battery to a condenser and thence to the cable, this
key after each signal putting the cable to earth which however does not suffice
to discharge the cable. According to the present invention the cable is dis-
charged at each signal by a reverse current of the same strength as the first,
these two currents being, according to this invention, very simply obtained
with a transformer instead of complex manipulating mechanism.
The transformer have the general formi shewn in Figures 5 to 9 inclusive. The
core consists of iron wires as indicated in Figure 6, or of thin strips of very soft
iron as indicated in Figure 7. There are two inducing circuits I I¹ coiled either
side by side or the one over the other. There are two induced circuits S S¹ which
can be connected in series or parallel or left separate as may be required. There
are also three circuits zzz always closed, each having only one layer of wire.
The circuit z is placed between the inducing and the induced circuits, the cir-
cuit in the middle of the induced circuits, and the circuit z11 outside the in-
duced circuit. These closed circuits take a large part of the self induction. For
each of them might be substituted a sheath or metal tube passed over each wind-
ing. This insulated independent self induction circuit which may be termed
parasite" is very useful whatever be its form, of which there may be many.
It limits the secondary current which might injure the cable and completely
annuls extra currents, whatever combination be adopted for the communications.
If Figure 10 be taken as the arrangement with double key with the inducing
circuits II in series, at each touch the primary local circuit would be closed
and opened, but on its opening all the extra current would pass to the cable
but for the closed independent circuit shewn dotted, where it is quite absorbed.
Figure 11 shews an arrangement having the inducing circuits parallel.
Instead of a closed parasite circuit indicated by dotted lines a resistance might
be employed such as a bobbin F Figure 12, water V Figure 13 or a condenser G
Figure 14 in shunt with the ends S S¹ of the induced circuit leading the one to
earth the other to line.
The arrangements of the circuits I I¹, S S¹, Z Z Z may be applied to simple.
induction coils with straight core as in Figure 9 and generally to any kind of
coil as the invention does not apply to the form of the coil, but to the combina-
tion of the circuits of its windings.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1
1. The herein described method of telegraph transmission especially submarine,
by splitting each signal into two secondary currents one for charge and one for
discharge, obtained by working a single contact transmitter with a transformer,
the discharge current serving to restore the line to neutral condition after each
signal.
2. The combination of an automatic transmitter of Wheatstone kind with one
or two transformers like induction coils, and with a single or double relay if
required for the transmitter.

page_text: 3. In combination with the transformer one or more parasite coils for the pur-
pose set forth.
4. In the transformer the use of two distinct inducing coils side by side,
capable of being employed as one.
Dated this fith day of Anvil
1900
ABEL & IMRAY,
Agents for the Applicant.