Improvements in the Manufacture of Rubber Composition Strips Used in the Manufacture of Insulated Wires and Cables.
Year: 1887

page_text: Date of Application, 18th Aug., 1887
Complete Left, 11th May, 1888
Complete Accepted, 22nd June, 1888
Improvements in the Manufacture of Rubber Composition Strips
Used in the Manufacture of Insulated Wires and Cables.
I, ROBERT HANNAN of 162 Buchanan Street, Glasgow, in the County of Lanark
Merchant, do hereby declare the nature of this invention, a communication to me from
abroad by J. J. C. Smith of the City of Passaic, County of Passaic, State of New
Jersey in the United States of America, to be as follows:
The object of this invention is the production of long narrow strips of vulcanized
india-rubber compound which are to be used for winding around wires and cables to
effect insulation.
In order to show the novelty and utility of the present invention it will be necessary
to give a short description of the manner which is in use at present for the production
of rubber strips used for winding around wires and cables for insulation purposes.
The strips are cut from blocks of pure, fine, Para rubber; the manner in which
they are cut is too well known, by those in the business, to require description, as are
also the reasons why they are cut from pure Para rubber.
It is likewise known that pure Para is very expensive material and that the
preparing of fine Para into blocks and the cutting of the same into strips involves a
great deal of labor.
Many attempts have been made to form strips from vulcanized rubber sheets of a
cheaper compound. However when such sheets are vulcanized in the manner as at.
present in use, that is to say, vulcanized between cloth, it has been found that the
rubber sheets are not perfectly waterproof, and they are consequently unfit for good
insulation. Furthermore the production of vulcanized rubber sheets in great lengths,
say of 1500 or 2000 feet is almost impossible. To resort to short lengths presents the

page_text: difficulty of perfect splicing of vulcanized strips and for these reasons resort is had to
the Para strips although they are most expensive.
By use of the present invention these difficulties are fully overcome and great
savings in cost of material and labor are effected, likewise a more effective and durable
insulation can be produced.
When rubber compound sheets are vulcanized between cloth, in open steam as it
is usually done it will be found on careful examination and testing, that such rubber
sheets are not what may be termed waterproof for electrical insulation. This is
produced by the moisture of the steam coming into contact with the compound during
the vulcanization process.
I overcome this bad effect entirely and can produce an absolutely waterproof sheet
of vulcanized rubber_compound of great strength and durability, by vulcanizing my
rubber sheets between flexible soft metal sheets or tinfoil.
The manner in which this is effected and strips of any desirable width produced is
as follows: A tin block of 14 to 18 inches wide, 18 inches long and about 1 inch
thick is rolled out into a sheet of about No. 30, B.W.G. which makes a sheet of about
200 feet in length. A tin block of other suitable dimensions may however be
employed.
This sheet of tin foil receives on one side a thin coating of rubber cement.
When so prepared the tin sheet goes to the rubber calender and a sheet of rubber
compound is calendered on the prepared side.
The rubber so laid on the tin is calendered in the desired thickness. After this is
done, the tin sheet with the raw rubber compound on one side, is put on a suitable
cutting machine and is cut into strips of about 1 to inches wide.
On account of the unelastic tin sheet being in combination with the soft elastic
rubber the cutting is easily effected.
After this, those strips (being 200 feet long each, or of other convenient length) are
joined together by soldering the ends of the tin butt to butt with soft solder that will
melt at a lower temperature than the tin. When the tin foil strip is thus joined the
rubber strip is joined carefully at the same place. This operation is continued joining
strip to strip until a continued length of about 2,000 feet is obtained.
This long strip is then carefully and solidly rolled on a light metal rim of about
18 inches diameter, the rim being of same width as the strip. After being rolled up
in this manner a number of such rolls are packed in a pan with soapstone powder and
placed in a suitable vulcanizing vessel, to be cured according to the nature of the
rubber compound used. When these strips are cured they may be cut into narrower
strips with great facility and of uniform width, on account of the tin strip being still
united with the rubber. After this cutting the tin foil is removed from the rubber
strip (which operation is easy) and a very strong elastic rubber strip of great length
is produced.
This vulcanized rubber strip is placed on a proper reel for the taping machine by
means of which it is wound around the wire for insulation in the same manner as the
pure rubber strips are now applied.
The great advantages obtained by the present invention are these :-
First. It is known that good vulcanized rubber compound strips are more durable
against the changes of air, temperature and action of atmosphere and gases than fine
Para strips.
Second. Very good rubber compound strips can be made for half the price of Para
strips.
Third. The most important point of the present invention is, that by vulcanizing
the rubber compound strip united with a tin foil strip and closely rolled up as
described, the moisture of steam or air is fully prevented from coming into contact
with the rubber compound during the process of its vulcanization, the result of which
will be the production of a much stronger strip which will be perfectly moisture
proof and waterproof for electric insulating purposes.
Fourth. By the combination of a soft metallic sheet with the elastic rubber the work

page_text: of cutting the strips of a uniform width is facilitated as is also that of the production
of a very long strip.
Wires or cables wound over with strips made in the manner above described
may receive another jacket covering of rubber compound which may be laid over the
wound covering.
The laying of a jacket or outside covering over the wound insulation may be effected
by means of a so called rubber tubing machine or by means of the covering machine
described in the Specification of Letters Patent granted to J. J. C. Smith No. 4768
dated October 7th 1882 or by other suitable means.

page_text: Used in the Manufacture of Insulated Wires and Cables.
I, ROBERT HANNAN of 162 Buchanan Street, Glasgow, in the County of Lanark,
Merchant do hereby declare the nature of this invention, a communication to me
from abroad by James Joseph Charles Smith of the City of Passaic, County of
Passaic, State of New Jersey, in the United States of America, and in what manner
the same is to be performed, to be particularly described and ascertained in and by the
following statement :―
The object of this invention is the production of long narrow strips of vulcanized
india rubber compound, which are to be used for winding around wires and cables
to effect insulation.
In order to show the novelty and utility of the present invention, it will be
necessary to give a short description of the manner which is in use at present for
the production of rubber strips used for winding around wires and cables for
insulation purposes.
The strips are cut from blocks of pure fine Para rubber. The manner in which
they are cut is too well known by those in the business to require description, as
are also the reasons why they are cut from pure Para rubber.
It is likewise known that pure Para is very expensive material, and that the
preparing of fine Para into blocks, and the cutting of the same into strips involves
a great deal of labour.
Many attempts have been made to form strips from vulcanized rubber sheets of
a cheaper compound.
However, when such sheets are vulcanized in the manner as at present in use,
that is to say, vulcanized between cloth, it has been found that the rubber sheets
are not perfectly waterproof, and they are consequently unfit for good insulation.
Furthermore, the production of vulcanized rubber sheets in great lengths, say
of 1500 or 2000 feet, is almost impossible. To resort to short lengths presents the
difficulty of perfect splicing of vulcanized strips, and for these reasons resort is had
to the Para strips although they are most expensive.
By use of the present invention, these difficulties are fully overcome, and great
savings in cost of material and labour are effected, likewise a more effective and
durable insulation can be produced.
When rubber compound sheets are vulcanized between cloth in open steam, as it is
usually done, it will be found, on careful examination and testing, that such rubber
sheets are not, what may be termed, waterproof, for electrical insulation. This is
produced by the moisture of the steam coming into contact with the compound during
the vulcanization process.

page_text: I overcome this bad effect entirely, and can produce an absolutely waterproof sheet
of vulcanized rubber compound of great strength and durability, by vulcanizing my
rubber sheets between flexible soft metal sheets or tinfoil.
The manner in which this is effected, and strips of any desirable width produced
is as follows—
A tin block of any suitable dimensions, say, for example, from 14 to 18 inches
wide, 18 inches long, and about 1 inch thick, is rolled out into a sheet of about
No. 30, B.W.G, which makes a sheet of about 200 feet in length.
This sheet of tin foil is prepared on one side with a thin coating of rubber cement.
When so prepared the tin sheet goes to the rubber calender, and a sheet of rubber
compound is calendered on the prepared side of the tin sheet.
The rubber so layed on the tin is calendered in the desired thickness. After this is
done, the tin sheet with the raw rubber compound on one side, is put on a suitable
cutting machine and is cut into strips of about 1 to 2 inches wide, or of other
suitable width.
On account of the inelastic tin sheet being in combination with the soft elastic
rubber, the cutting is easily effected.
After this, those strips (boing 200 feet long each, or of other convenient length)
are joined together by soldering the ends of the tin, butt to butt with soft solder
that will melt at a lower temperature than the tin. When the tin foil strip is thus
joined, the rubber strip is joined carefully at the same place by means of a solvent
or india rubber solution, as is well known. This operation is continued joining strip
to strip until a continued length of about 200 feet is obtained.
This long strip is then carefully and solidly rolled on a light metal ring or wheel of
about 18 inches diameter, the ring or wheel being of same width as the strip. After
being rolled up in this manner, a number of such rolls are packed in a pan with soap
stone powder and placed in a suitable vulcanizing vessel, to be cured according to the
nature of the rubber compound used.
When these strips are cured, they may be cut into narrower strips with great
facility and of uniform width, on account of the tin strip being still united with the
rubber. After this cutting, the tinfoil is removed from the rubber strip (which
operation is easy) and a very strong elastic rubber strip of great length is produced.
This vulcanized rubber strip is placed on a proper reel for the taping machine, by
means of which it is wound around the wire for insulation in the some manner as the
pure rubber strips are now applied.
The great advantages obtained by the present invention are these:-
First: It is known that good vulcanized rubber compound strips are more durable
against the changes of air, temperature, and action of atmosphere and gases than fine
Para strips.
Second-Very good rubber compound strips can be made for half the price of
Para strips.
Third The most important point of the present invention is, that, by vulcanizing
the rubber compound strip united with a tin foil strip and closely rolled up as
described, the moisture of steam or air is fully prevented from coming into contact
with the rubber compound during the process of its vulcanization, the result of which
will be the production of a much stronger strip which will be perfectly moisture proof
and water proof for electric insulating purposes.
Fourth -By the combination of a soft metallic sheet with the elastic rubber, the
work of cutting the strips of a uniform width is facilitated, as is also that of the
production of a very long strip.
Wires or cables wound over with strips made in the manner above described may
receive another jacket covering of rubber compound which may be laid over the
wound covering.
The laying of a jacket or outside covering over the wound insulation may be
effected by means of a, so called, rubber tubing machine, or by means of the covering
machine described in the specification of Letters Patent granted to J. J. C. Smith
No. 4768 dated October 7, 1882, or by other suitable means.

page_text: 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. Vulcanizing elastic rubber compound sheets, which are to be used for insulation
of electric conductors, between sheets of tinfoil, for the purpose, and in the manner,
described.
2. The combination of tinfoil with rubber sheets during the process of manufacture
for the purposes and in the manner specified.