IMPROVEMENTS IN THE MANU- FACTURE OF INSULATED TELEGRAPHIC CONDUCTORS AND OF INSULATING MATERIALS TO BE EMPLOYED THEREIN, WHICH MATERIALS ARE ALSO APPLICABLE TO OTHER PURPOSES
Year: 1878

page_text: "
LETTERS PATENT to Edwin Thomas Truman, of Old Burlington Street, in
the County of Middlesex, for the Invention of IMPROVEMENTS IN THE MANU-
FACTURE OF INSULATED TELEGRAPHIC CONDUCTORS AND OF INSULATING
MATERIALS TO BE EMPLOYED THEREIN, WHICH MATERIALS ARE ALSO
APPLICABLE TO OTHER PURPOSES."
Sealed the 22nd March 1878, and dated the 29th January 1878.
PROVISIONAL SPECIFICATION left by the said Edward Thomas Truman at
the Office of the Commissioners of Patents on the 29th January 1878.
EDWIN THOMAS TRUMAN, of Old Burlington Street,.in the County of Middlesex.
"IMPROVEMENTS IN THE MANUFACTURE OF INSULATED TELEGRAPHIC CONDUCTORS,
AND OF INSULATING MATERIALS TO BE EMPLOYED THEREIN, WHICH MATERIALS ARE
ALSO APPLICABLE TO OTHER PURPOSES."
India-rubber both in the masticated and vulcanized forms, and both alone and
mixed with other materials, gutta percha, or sulphur, for example, is well known
as an insulating material; but when exposed to water it is more or less porous in
all its states and mixtures, with the exception of the state known as vulcanite,
ebonite, or hard rubber. In this state it is capable of resisting the action of
water, but owing to its brittle nature it has not hitherto been successfully applied as
an insulating covering to telegraph wire, which requires to be bent and coiled
during the laying and fixing.
Now according to my Invention I cover the wire with vulcanite, and in order to
give the covered wire the necessary power of bending without the vulcanite cracking
or becoming ruptured I cover the vulcanite with lead.
I find that vulcanite covered wire possessing flexibility can be produced by first
covering the tinned wire with a suitable thickness of the necessary materials and
then inserting the covered wire into a lead tube and baking or curing it at the
proper temperature for a sufficient length of time to convert the materials into
vulcanite, as is well understood.

page_text: I also find that solvents such as paraffin and ozokerit and other like waxes may
be used with advantage in the manufacture of vulcanite or insulating material for
covering telegraph wires, that is to say, I mix the paraffin or other wax with the
india-rubber and sulphur (or its compounds) with or without gutta or other
materials before the baking or curing process.
I am aware that in the Specification of Letters Patent granted to Frederick
Field and Richard Talling, dated 27 May, 1875, No. 1938, it was proposed to make
an insulating compound from india-rubber and ozokerit. But this compound was
obtained by amalgamating the ingredients by means of solvents and mixing them
together, or by simply masticating the ingredients together; and it was proposed in
some cases to vulcanize or semi-cure the compound in the same manner as india-
rubber is usually treated for that purpose. In no case, however, was fusion or
high temperature employed in making the compound, nor was sulphur or any com-
pound of sulphur one of the ingredients used, nor was the material produced of the
nature of vulcanite. But in manufacturing my improved insulating material I mix
and incorporate india-rubber, ozokerit (or other wax), and sulphur (or its compounds)
together, with or without gutta percha or other materials, and then submit the
mixture, as will be well understood, to the requisite heat, and for the requisite
length of time, under pressure or confinement, to convert it into a species of
vulcanite or hard insulating material. Or instead of employing india-rubber I use
gutta percha, balata, or other such like material, together with ozokerit (or other
wax) and sulphur (or its compounds) with or without pigments or other
materials.
My improved insulating material, although specially intended for telegraph wires
and to be covered with lead, as herein-before described, may be used as an'insulating
material without a lead covering, or the material may be applied to other uses such
as those for which ordinary vulcanite is now employed, dental purposes for
example.
Another objection hitherto to the use of vulcanite as a covering to telegraph
wire has been the impossibility of producing chemical union of the vulcanite at the
joints, which have to be made in long lengths of wire. I find that if lead be used
as a covering to the vulcanite the defective joint of the vulcanite is remedied by
producing a perfect soldered joint in the lead covering, the vulcanite bearing the
requisite heat.
Now that I have pointed out how the objections to the use of vulcanite as a
covering to telegraph wires can be overcome, it is easy to vary the mode of meeting
the difficulty. For example, instead of lead other soft metals may be used; or even
substances not metallic, provided they will allow of the vulcanite being cured
under pressure or confinement; or the vulcanite can be put on the wire by lapping
or through dies, or it may be partially or entirely cured and be then placed in the
metal tube and the tube be drawn over the vulcanite. Or other materials, hemp
or gutta percha, for instance, may be placed over the vulcanite and be thien covered
with lead or other metallic covering, but the covering must in all cases be such as
will prevent the cracking of the vulcanite when coiled or bent.
Proper proportions of materials for making the vulcanite and, the time required
for curing are well known; experience inust shew what proportions and what time
are best when the vulcanite has to be employed for insulating telegraph wire, .as
herein-before described.
Although I have referred to vulcanite as the insulating material, to which I give
the requisite flexibility by covering it with lead, the lead or analogous material
may also be applied to other insulating coverings of.a. hard or brittle nature, such
for example as parkesine.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
"
the said Edwin Thomas Truman in the Great Seal Patent Office on the
29th July 1878.
EDWIN THOMAS TRUMAN, of Old Burlington Street, in the County of Middlesex.
IMPROVEMENTS IN THE MANUFACTURE OF INSULATED TELEGRAPHIC CONDUCTORS,
AND OF INSULATING MATERIALS TO BE EMPLOYED THEREIN, WHICH MATERIALS ARE
ALSO APPLICABLE TO OTHER PURPOSES."
India-rubber, both in the masticated and vulcanized forms, and both alone and
mixed with other materials, gutta percha or sulphur, for example, is well known as
an insulating material, but when exposed to water it is more or less porous in all
its states and mixtures, with the exception of the state known as vulcanite, ebonite,
or hard rubber. In this state it is capable of resisting the action of water, but
owing to its brittle nature it has not hitherto been successfully applied as an insu-
lating covering to telegraph wire, which requires to be bent and coiled during the
laying and fixing.
Now according to my Invention I cover the wire with vulcanite, and in order to
give the covered wire the necessary power of bending without the vulcanite
cracking or becoming ruptured I cover the vulcanite with lead.
I find that vulcanite covered wire possessing flexibility can be produced by first
covering the tinned wire with a suitable thickness of the necessary materials, and
then inserting the covered wire into a lead tube and baking or curing it at the
proper temperature for a sufficient length of time to convert the materials into
vulcanite, as is well understood.
I also find that solvents such as paraffin and ozokerit and other like waxes, may
be used with advantage in the manufacture of vulcanite or insulating material for
covering telegraph wires, that is to say, I mix the paraffin or other wax with the
india-rubber and sulphur (or its compounds) with or without gutta percha or other
materials before the baking or curing process.
I am aware that in the Specification of Letters Patent granted to Frederick Field
and Richard Talling, dated 27th May 1875, No. 1938, it was proposed to make an
insulating compound from india-rubber and ozokerit. But this compound was
obtained by amalgamating the ingredients by means of solvents and mixing them
together, or by simply masticating the ingredients together, and it was proposed in
some cases to vulcanize or semi-cure the compound in the same manner as india-
rubber is usually treated for that purpose. In no case, however, was fusion or high
temperature employed in making the compound, nor was sulphur or any other
compound of sulphur one of the ingredients used, nor was the material produced of
the nature of vulcanite. But in manufacturing my improved insulating material I
mix and incorporate india-rubber, ozokerit (or other wax) and sulphur (or its com-
pounds) together, with or without gutta percha or other materials, and then submit
the mixture, as will be well understood, to the requisite heat and for the requisite
length of time under pressure or confinement to convert it into a species of vulcanite
or hard insulating material. Or instead of employing india-rubber I use gutta
percha, balata, or other such like material, together with ozokerit (or other wax) and
sulphur (or its compounds) with or without pigments or other materials.
My improved insulating material, although specially intended for telegraph wires,
and to be covered with lead, as herein-before described, may be used as an insulating
material without a lead covering, or the material may be applied to other uses
such as those for which ordinary vulcanite is now employed, dental purposes for
example.
Another objection hitherto to the use of vulcanite as a covering to telegraph
wire has been the impossibility of producing chemical union of the vulcanite at the
joints, which have to be made in long lengths of wire. Now I use lead as a
covering to the vulcanite at the joint, the defective joint is remedied by producing a

page_text: perfect soldered joint in the lead covering, the vulcanite bearing the requisite
-heat.
In carrying out this part of my Invention I bare the wire as usual and unite the
ends; I then place a tube or ferrule of lead over the lead covering of the vulcanite
covered wire, and united to the lead covering by soldering. The interior of the lead
tube or ferrule may be filled with any suitable material, such, for instance, as
melted ozokerit, as will be well understood.
Now that I have pointed out how the objections to the use of vulcanite as a
covering to telegraph wires can be overcome, it is easy to vary the mode of meeting
the difficulty. For example, instead of lead other soft metal may be used, or even
substances not metallic, provided they will allow of the vulcanite being cured under
pressure or confinement; or the vulcanite can be put on the wire by lapping or
through dies, or it may be partially or entirely cured and be then placed in the
metal tube and the tube be drawn over the vulcanite. Or other materials, hemp
or gutta percha, for instance, may be placed over the vulcanite and be then covered
with lead or other metallic covering, but the covering must in all cases be such as
will prevent the cracking of the vulcanite when coiled or bent.
Proper proportions of materials for making the vulcanite and the time required
for curing are well known.
Although I have referred to vulcanite as the insulating material to which I give
the requisite flexibility by covering it with lead, the lead or analogous material
may also be applied to other insulating coverings of a hard or brittle nature, such,
for example, as parkesine.
In witness whereof, I, the said Edwin Thomas Truman, have hereunto set my
hand and seal, this Twenty-seventh day of July, One thousand eight
hundred and seventy-eight.
EDWIN THO³. TRUMAN. (L.S.)