IMPROVE- MENTS IN THE MANUFACTURE OF ELECTRICAL CONDUCTORS FOR TELEPHONIC OR OTHER PURPOSES to be as follows
Year: 1884

page_text: I EDWIN THOMAS TRUMAN of 23 Old Burlington Street in the County of
Middlesex Surgeon do hereby declare the nature of my invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF ELECTRICAL CONDUCTORS FOR TELEPHONIC OR
OTHER PURPOSES to be as follows:-
"
1.
i
My invention consists in forming electrical conductors for Telephonic or other
purposes of 2 or more wires or conductors wound spirally round a hard core or
round an insulated wire, the wires so placed being insulated from each other and
from the surrounding matter.
In the Specification of former Letters Patent granted to me and dated
14th August 1880 N° 3310 I described the manufacture of electrical conductors
composed of 2 or more spirally wound wires by embedding the conducting wires
in a solid piece of gutta percha or other insulating material. The manufacture as
then described is quite practicable but I find that the same object can be more
readily effected by twisting the wires round a hard core such as string or india
rubber or other non-plastic or hard matter, because the manufacture can then be
effected in the ordinary covering machines by first laying the 2 or more wires on
to the centre core spirally as is well understood and then passing the whole
through a die with gutta percha or other insulating material prepared for the
purpose, care being taken to ensure the absolute insulation of one wire from
another.
If the core I employ be of a fibrous material or of such a nature as would
interfere with the insulation of the wires I first prepare it by saturating it either
with Paraffin or some other suitable insulator, one that will penetrate being
preferred, or, I by other means render it fit for my purpose. Upon the core
I place my wires spirally with as much space between them as will insure that
they shall not touch each other-and I then either tape on the core to enclose the
wires with a properly prepared tape or covering or I run the wires and core
through an ordinary gutta percha covering machiue and so place a coating of gutta
percha over the wires and enclose them from external influence.
The core may be an insulated wire or it may be of india rubber or of fibrous or
other material covered with india rubber or with solution of caoutchouc or with
the composition known as Chatterton's compound; and the tape may also be

page_text: saturated with Chatterton's compound, or it may be an india rubber tape as now
sometimes used to cover wire; or any other insulating material may be employed
that will ensure the object of my invention which is to have two or more con-
ducting wires spirally arranged round a centre core insulated from each other, and
again insulated from surrounding matter.
Wires or conductors so made may be cured or vulcanized by using sulphur
compounds as is well understood.
In completing this or other forms of insulated conductor I prefer to run it from
the covering machine either into a trough of cold water, as is now practised, or
into a bath of warm water and I then coat the conductor with dry plumbago or
black lead very finely powered and this may conveniently be done by passing the
conductor as it cools on its way to the receiving drum as is well understood through
a trough to which the plumbago is supplied. Or, the soft gutta percha or other
like insulating substance may be kept dry and be run directly through a receptacle
containing plumbago.
By this means the surface will take up and become largely impregnated with the
plumbago which will form with the insulating material a durable covering to the
insulating material under this plumbago surface, and will protect it from oxidation.
Bands or strands may of course be used instead of simple wires.
According to another mode of manufacturing electrical conductors for telephonic
or other purposes with several wires or couductors wound spirally round a central
hard core I take a number of strands of hemp or other suitable material properly
prepared and of wires or other conductors placed alternately and I lay them
spirally round the central core so as to form a rope each wire or conductor being
insulated from the other wires or conductors by the interposed strands of hemp or
other material. I then cover the whole externally with an insulator either in the
form of tape or otherwise and in order to ensure its durability I coat this insulator
with plumbago applied either in the manner above described or otherwise.
Dated this 27th day of February 1884

page_text: ;
I EDWIN THOMAS TRUMAN, of 23 Old Burlington Street, in the County of
Middlesex, Surgeon do hereby declare the nature of my invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF ELECTRICAL CONDUCTORS FOR TELEPHONIC OR
"
OTHER PURPOSES and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
My invention consists in forming electrical conductors for telephonic or other
purposes of two or more wires or conductors wound spirally round a hard core or
round an insulated wire, the wires so placed being insulated from each, other and
from the surrounding matter.
In the Specification of former Letters Patent, granted to me and dated
14th August 1880, No 3310, I described the manufacture of electrical conductors
composed of two or more spirally wound wires by embedding the conducting wires
in a solid piece of gutta percha or other insulating material. The manufacture, as
then described, is quite practicable but I find that the same object can be more
readily effected by twisting the wires round a hard core, such as string or india
rubber or other non-plastic or hard matter, because the manufacture can then be
effected in the ordinary covering machines by first laying the two or more wires
on to the centre core spirally as is well understood and then passing the whole
through a die with gutta percha or other insulating material prepared for the
purpose, care being taken to ensure the insulation of one wire from another; the
result is a cable or rope in which the wires placed round the hard core are
embedded in one mass of insulating material so that there can be no surface
leakage between wire and wire.
I am aware that it is not new to twist two or more wires round a hard core as
this has been proposed for the purpose of preventing the breakage of the wires
during laying or stretching but in the case referred to no care was specially taken
to prevent surface leakage between wire and wire which for my purpose is most
essential.
If the core I employ be of a fibrous material or of such a nature as would
interfere with the insulation of the wires I first prepare it by saturating it either
with paraffin or some other suitable insulator, one that will penetrate being
preferred, or, I by other means render it fit for my purpose. Upon the core I place
my wires spirally with as much space between them as will insure that they shall
not touch each other, and I then either tape on the core to enclose the wires with
a properly prepared tape or covering, or I run the wires and core through an
ordinary gutta-percha covering machine and so place a coating of gutta-percha
over the wires and enclose them from external influence, or I cover the core with
tape and place the wires over the tape, and then coat with gutta percha.
The core may be an insulated wire or it may be of india-rubber or of fibrous or
other material covered with india rubber in the form of tape or otherwise, or with
solution of caoutchouc or with the composition known as Chatterton's compound;
and the tape may also be saturated with Chatterton's compound, or it may be an
india rubber tape as now sometimes used to cover wire; or any other insulating
material may be employed that will ensure the object of my invention which is to
have two or more conducting wires spirally arranged round a centre core insulated
from each other, and again insulated from surrounding matter.
Wires or conductors so made may be cured or vulcanized by using sulphur
compounds as is well understood,

page_text: When the hard core is an insulated wire it may be used as the return wire for
any of the wires which are wound spirally round it, these wires being insulated
from each other and from the surrounding matter as already stated. A telephone
wire and its return wire should not only be insulated from each other but be ast
nearly as possible equi-distant. from each other and from surrounding objects; this
is attained in the case of each of the telephone wires wound spirally round the
central insulated wire which may thus serve as the return wire for any of them.
In completing this or other forms of insulated conductor I prefer to run it from
the covering machine into a trough of cold water, with which plumbago or black-
lead, very finely powdered, is mixed.
...n
By this means the surface of the cable will take up and become largely impreg-
nated with the plumbago which will form, with the insulating material, a durable
covering to the insulating material under this plumbago surface, and will protect it
from oxidation.
Bands or strands may of course be used instead of simple wires.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In the manufacture of electrical conductors, placing two or more conductors
round a hard core, each conductor being insulated from the other conductors, and
from all surrounding matter, as described.
'
2. In the manufacture of electrical conductors, placing two or more conductors
round an insulated wire, each conductor being insulated from the other conductors,
and from all surrounding matter, as described.
3. In the manufacture of electrical conductors, placing two or more conductors
round a hard core, composed of india rubber or of fibrous material covered with
india-rubber or with solution of caoutchouc or with other suitable material, and
then covering the cable or compound conductor thus formed with gutta-percha, or
other insulating material, so that the conductors are insulated from each other, and
from all surrounding matter, as described.
4. A compound electrical conductor, composed of two or more conductors, placed
round a hard core, each conductor being insulated from the other conductors and
from all surrounding matter and the insulating material being coated with
plumbago, as described.
L
1