IMPROVEMENTS IN PRE- PARING GUTTA-PERCHA AND OTHER LIKE SUBSTANCES SUITABLE FOR INSU- LATING TELEGRAPHIC CONDUCTORS AND FOR OTHER PURPOSES, AND IN MACHINERY EMPLOYED IN THE PROCESS, AND ALSO IMPROVEMENTS IN MAKING UNIONS BETWEEN VARIOUS LENGTHS OF INSULATED CONDUCTORS
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 PRE-
PARING GUTTA-PERCHA AND OTHER LIKE SUBSTANCES SUITABLE FOR INSU-
LATING TELEGRAPHIC CONDUCTORS AND FOR OTHER PURPOSES, AND IN
MACHINERY EMPLOYED IN THE PROCESS, AND ALSO IMPROVEMENTS IN MAKING
UNIONS BETWEEN VARIOUS LENGTHS OF INSULATED CONDUCTORS."
sex.
PROVISIONAL SPECIFICATION left by the said Edwin Thomas Truman
at the Office of the Commissioners of Patents on the 2nd November 1878.
EDWIN THOMAS TRUMAN, of Old Burlington Street, in the County of Middle-
"IMPROVEMENTS IN PREPARING GUTTA-PERCHA AND OTHER LIKE SUBSTANCES
SUITABLE FOR INSULATING TELEGRAPHIC CONDUCTORS AND FOR OTHER PURPOSES,
AND IN THE MACHINERY EMPLOYED IN THE PROCESS, AND ALSO IMPROVEMENTS
IN MAKING UNIONS BETWEEN VARIOUS LENGTHS OF INSULATED CONDUCTORS."
In preparing gutta-percha or other like substances for covering telegraphic con-
ductors it is usual first to wash and cleanse the material and then to masticate or
kuead it into a more or less homogeneous mass, and in so doing to more or less
remove the water and air left in the material by the process of cleansing. This
masticating operation as hitherto practised I have found to be injurious, as it
impairs the quality of the prepared material. This defect it is the object of my
improved process of preparation hereinafter described to obviate.
In the Specification of former Letters Patent granted to me, and dated 25th
March 1870, No. 878, for "Improvements in Treating and Preparing Gutta-percha
and other like Substances, and in Machinery Used in the Preparing Process," I
proposed to pass the material taken from the washing machine with the water and
air in it into and through a tube leading from the end of a screw into a hopper,
Panice 11

page_text: UHIC II
the material was consequently converted into steam, and the action was kept up or
repeated until all the moisture and air were removed.
In all these methods of preparing the material the water is either removed by
long mastication in a kneading machine, as in the node heretofore generally
-followed, or it is removed by means of its conversion into steam in a heated tube,
as described in my Specification above referred to.
-As-above-mentioned,-I-find-from-practice-and-experiment that masticating or
kneading when carried on in the ordinary way is very injurious to gutta-percha,
-and-that if the water used in cleansing be removed (which can be done without
inastication by simply wedging open tlie mass and allowing-the-steam-to-pass-off-),
the consolidation or condensation of the spongy mass will be effected by allowing
the escape of air and by laying what may be termed the fibres of the material in
close and regular order during its operation. Machines of various constructions may
be employed for carrying out my improved treatment, but masticators as hitherto
..employed are not required.
In my improved process of preparing gutta-percha, in which I reduce it in the
cleansing operation to a spongy porous mass, I submit the material afterwards to a
twisting action produced by a machine of a character hereinafter described, which
operation I term spinning. Its effect upon the material is very beneficial, as it
causes the air to be expelled from the cells or pores of the spongy cleansed material
without injuriously breaking up or kneading the particles or injuriously disturbing
the relative position in which they are placed as the sap originally exudes while
forming a gum such as gutta-percha.
It is well known that kneading india-rubber will entirely alter its physical state,
rendering it more easily soluble and non elastic, and if carried to extreme reduces
it to a soft putty like mass. I find that gutta-percha is likewise quite altered by
mastication; its physical character is not so apparently modified, but its durability
and textile strength are considerably lessened, and can be entirely destroyed if the
process of mastication be carried to excess.
The difference between mastication as now used and the spinning or twisting
process which I propose for consolidation lies in the fact that mastication forces the
particles of the material closer together, by kneading the mass into itself under
great pressure, whilst I, using little or no pressure, force out the air from the pores
or cells in which it is confined by twisting the spongy mass little by little around
itself, thereby elongating and gradually opening the air cells and expelling
the air.
For the reasons above indicated I dispense with the operation of masticating the
material by treating it in a masticator in the ordinary manner; again, I do not
treat the material in the manner described in the Specification of my said Patent
-of-March 25th, 1870, but as above stated, I first cleanse the raw material and reduce
it to a porous spongy mass filled with water and air; I then remove the water and
afterwards remove the air by my improved method of preparing and treating the
material which gives it an improved character and qualities superior to those here
tofore possessed by like gums when prepared in the ordinary way. The improved
material is more suitable for being used for telegraphic wire and other purposes
than any like material which has been prepared in the ordinary way.
In carrying out my improved process of preparation I proceed as follows:-I first
cleanse the material by treating it in hot water in a washing or cleansing machine,
which may be constructed in the ordinary way. These washing machines are now
well understood, and are various in their construction, but to perform my new
process properly care must be taken to use a washing machine that does not knead
the material into a homogeneous state during the operation, but leaves the gutta-
percha open and spongy. I find that the washing operation may be effected advan-
tageously in the manner described in the Specification of Letters Patent granted to
me, dated 5th January 1870, No. 41, or in some other manner that will effect the
same object. When the material has been sufficiently cleaused in water, I then

page_text: remove the heated water from the machine used for cleansing and continue the
action of the machine until the moisture, but not the air, is removed, I then intro-
duce the material thus treated while it is in a porous state and having cells filled
with air into a machine so constructed as to effect the removal of the air still con-
tained in the spongy mass without disturbing to too great extent the relative
position of the particles in the mass. This operation is effected by treating the
partially prepared material in a machine in which one or more spindles, by preference
square, or fitted with blades and conical, or a bundle of rods, or discs, or a screw or
screws are made to work on an axis or other arrangements so as to cause a twisting
or spinning action by rotation in a chamber with free access of air, near to but not
touching the side or wall of the chamber. The spindle should be caused to rotate
at a moderate velocity, so that the rotation causes the material to be thrown on to
a plane in front of the rotating spindle, and so form a mass of material, which
rotates on and into itself, while the outer surface is constantly changing and
spinning round. By this means from the nature of the material every part of the
mass will be brought to the surface, and the vesicles or cells containing air being
elongated will burst, and thus set free the air, and the walls of the vesicle or tube
by collapsing will adhere solidly together and combine in a consolidated form with
the mass of material operated on. This action must only be continued long enough
to ensure the requisite amount of solidification. When the action is complete the
material may be carried forward or discharged by a screw working under the mass.
The rate of passage must be regulated by a properly constructed exit, by means of
which the velocity may be altered or the passage be arrested for a time.
The
material may be made to pass into a second chamber, and be forced into moulds or
be formed into rods or sheets by the form of openings out of this second chamber,
arranged as required, or it may be applied directly as an insulating covering for
telegraph wire. In some cases I place the spongy material directly in a covering
machine of proper construction, where it is treated in the manner above described
so as to be free from air and consolidated during the process of covering. I find
that gutta percba may by this method be efficiently and economically employed as
an insulating material, and the gutta percha so prepared is rendered clean, dry, and
solid, and will be found in its insulating character much superior to gutta percha
treated as heretofore in the ordinary way.
Another part of my Invention relates to an improved method of making
joints.
In the Specification of my Letters Patent of 9th January 1874, No. 124, I
described that I made a union of the gutta percha covering in various lengths of tele-
graphic conductors by means of a mould having an opening communicating with a
filling machine. I have since found in practice that there is a difficulty in pre-
venting the pressure of the filling machine on the stream of gutta percha from
forcing the wire in the direction of such pressure, and thereby taking it out of the
central position it ought to occupy. In order to obviate this difficulty I cause the
filling machine to fill a chamber in which is a mould, which I find may be advan-
tageously made of perforated metal, so as to have numerous holes through which
the gutta percha may enter on all sides in small threads and all air may escape
readily. By this means sufficient pressure is given to the gutta percha particles so
as to ensure their union and the escape of air without diverting the wire. In some
cases the gutta percha may be laid on in layers, the apparatus being modified
accordingly. In some cases the mould may be permanently attached to the
joint.
I also find that the gutta percha may be either prepared free from air before it is
used, or a filling machine may be constructed of a single screw working in a small
tube with an opening for the supply thereto. Or a piston in a cylinder may be
employed to force the prepared material into the chamber, and thence into the
mould. I prefer a screw as above described.

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
2nd May 1879.
EDWIN THOMAS TRUMAN, of Old Burlington Street, in the County of Middlesex.
"IMPROVEMENTS IN PREPARING GUTTA PERCHA AND OTHER LIKE SUBSTANCES
SUITABLE FOR INSULATING TELEGRAPHIC CONDUCTORS AND FOR OTHER PURPOSES,
-AND-IN-MACHINERY EMPLOYED IN THE PROCESS, AND ALSO IMPROVEMENTS IN
MAKING UNIONS BETWEEN VARIOUS LENGTHS OF INSULATED CONDUCTORS."
In preparing gutta percha or other like substances for covering telegraphic
conductors, it is usual first to wash and cleanse the material, and then to masticate
or knead it into a more or less homogeneous mass, and in so doing to more or less
remove the water and air left in the material by the process of cleansing. This
masticating operation as hitherto practised I have found to be injurious, as it
injures the quality of the prepared material. This defect it is one of the objects of
my improved process of preparation hereinafter described to obviate.
In the Specification of former Letters Patent granted to me and dated 25th March
1870, No. 878, for "Improvements in Treating and Preparing Gutta Percha and
other like Substances, and in Machinery Used in the Preparing Process," I proposed
to pass the material taken from the washing machine with the water and air in it
into and through a tube leading from the end of a screw into a hopper, the material
being forced by the screw and the tube being heated. The water in the material
was consequently converted into steam, and the action was kept up or repeated
until all the moisture and air were removed.
In all these methods of preparing the material, the water is either removed by
long mastication in a kneading machine as in the mode heretofore generally
followed, or it is removed by means of its conversion into steam in a heated tube,
as described in my Specification above referred to.
As above mentioned I find from practice and experiment that masticating or
kneading when carried on in the ordinary way is very injurious to gutta percha,
and that if the water used in cleansing be removed (which can be done without
mastication by simply wedging open the mass and allowing the steam to pass off),
the consolidation or condensation of the spongy mass will be effected by allowing
the escape of air, and by laying what may be termed the fibres of the material in
close and regular order during its operation. Machines of various constructions
may be employed for carrying out my improved treatment, but masticators as
hitherto employed are not required.
In my improved process of preparing gutta percha I reduce it in the cleansing
operation into the state of a spongy porous mass, and I submit the material
afterwards to a twisting action produced by a machine of the character hereinafter
described, which operation I term "spinning." Its effect upon the material is very
beneficial, as it causes the air to be expelled from the cells or pores of the spongy
cleansed material without injuriously breaking up or kneading the particles, or
injuriously disturbing the relative position in which they are placed as the sap
originally exudes while forming a gum, such as gutta percha.
It is well known that kneading india rubber will entirely alter its physical state,
rendering it more easily soluble and non-elastic, and if carried to extreme reduces
it to a soft putty like mass; I find that gutta percha is likewise quite altered by
mastication, its physical character is not so apparently modified, but its durability
and textile strength are considerably lessened, and can be entirely destroyed if the
process of mastication be carried to excess.
The difference between mastication as now used, and the spinning or twisting
process which I propose for effecting without injury, the required consolidation of
the material lies in the fact that mastication forces the particles of the material
closer together by kneading the mass into itself under great pressure, whilst I,

page_text: using little or no pressure force out the air from the pores or cells in which it is
confined, by twisting the spongy mass little by little around itself, thereby
elongating and gradually opening the air cells and expelling the air.
For the reasons above indicated I dispense with the operation of masticating the
material by treating it in a masticator in the ordinary manner; again I do not
treat the material in the manner described in the Specification of my said Patent of
March 25th 1870, but as above stated I first cleanse the raw material, and reduce
it to a porous spongy mass filled with water and air; I then remove the water and
afterwards remove the air by my improved method of preparing and treating the
material, which gives it an improved character and qualities superior to those here-
tofore possessed by like gums when prepared in the ordinary way. The improved
material is more suitable for being used for telegraphic wire and other
than any like material which has been prepared in the ordinary way.
purposes,
In carrying out my improved process of preparation I proceed as follows:-I first
cleanse the material by treating it in hot water in a washing or cleansing machine
which may be constructed in the ordinary way. These washing machines as
applied to gutta percha or other like gums are now well understood and are various
in their construction; but to perform my new process properly care must be taken
to use a washing machine, so constructed that it does not knead the material into a
homogeneous state during the operation, but leaves the gutta percha open and
spongy; I find that the washing operation may be effected advantageously in the
manner described in the Specification of Letters Patent granted to me dated 5th
January 1870, No. 41, or in some other manner that will effect the same object.
When the material has been sufficiently cleansed in water, I then remove the
heated water from the machine used for cleansing, and continue the action of the
machine until the moisture but not the air is removed; I then introduce the
material thus treated while it is in a porous state, and having cells filled with air
into a machine so constructed as to effect the removal of the air still contained in
the spongy mass, without disturbing to too great an extent the relative position of
the particles in the mass. This operation is effected by treating the partially
prepared material in a machine constructed as follows:-
One or more spindles, by preference square or fitted with blades, or a bundle of rods
or discs, or a screw or screws, are made to work in a chamber upon an axis, or other
like mechanical arrangements may be employed so as to cause a twisting or spinning
action by rotation in the chamber, provision being made for the free access of air,
as may be done with advantage by making the top of the chamber open, and the
spindle or its equivalent being set, not centrally with reference to the chamber, but
nearer to one of its sides or walls than to the others, so that the material is forced
by the rotation of the spindle into the narrowest part of the chamber. The spindle
should be caused to rotate at a moderate velocity, so that the rotation causes the
material to accumulate in the narrow part of the chamber in front of and above the
rotating spindle, and so form a mass of material which rotates on and into itself,
while the outer surface is constantly changing and spinning round. In the ordinary
process of mastication the mass of gutta percha is carried round the interior of the
cylinder or between the spindles, and does not at the temperature ordinarily
employed adhere to the metal of the machine, but in the arrangement of mechanism
used by me in my improved process, the spindle or screw that turns over and
twists the material works near to one side of (but not touching) the chamber, and
so prevents the whole mass of the material from passing on its way as in a
masticator, by reason of the small space left in front between the spindle and the
side of the chamber, and the material partially adheres to the metal both of the
spindle and the chamber and is thereby caused to be turned and twisted, and so to
speak circulate within itself. By this means from the nature of the material every
part of the mass will be brought to the surface, and the vescicles or cells containing
air being elongated will burst and thus set free the air, and the walls of the vesciclo
or cell by collapsing will adhere solidly together and combine in a consolidated form
with the mass of material operated on. This action must only be continued long

page_text: enough to ensure the requisite amount of solidification. When the action is
complete the material may be carried forward or discharged by a screw working
under the mass against the end of the cylinder as described in the Specification of
my said Patent of 25th March 1870. The rate of passage must be regulated-by-a-
properly constructed exit (fitted with a tap or other suitable device by means of
which the velocity of discharge may be altered or the passage be arrested for a time.
The material may be made to pass into-a-second chamber and be forced into moulds
or be formed into rods or sheets by the form of openings out of this second chamber
arranged as required, or it may be applied directly as an insulating covering for
telegraph wire.
It should be noted that the material while being treated in the manner above
described must be maintained at a suitable temperature to permit of the spinning
or twisting action being performed, as will be well understood. This may be readily
provided for by enclosing the walls of the chamber in a hot water jacket or by
otherwise applying such heat as may be necessary.
In some cases the insulating material, when it has been treated in the manner
above described so as to be freed from air, and is then consolidated by what I have
termed the twisting or spinning operation, is then delivered into a covering machine
and applied to cover wire. The quantity of material delivered to the covering
machine from the spinning machine is regulated by causing it to pass through an
opening or channel, the outlet of which is controlled so that it may be made larger
or smaller, or closed altogether. I find that gutta percha may by this method be
efficiently and economically employed as an insulating material, and the gutta
percha so prepared is rendered clean,, dry, and solid, and will be found in its
insulating character much superior to gutta percha treated as heretofore in the
ordinary way.
Another part of my Invention relates to an improved method of making joints, and
has reference to the mode of making joints or unions in the gutta percha covering
of telegraphic conductors by means of a mould, in which mould the portions of
the conductor to be united are placed, and into which mould the gutta percha in
a heated state is forced by a suitable filling machine. This mode of making unions
(which is described in the Specification of my Letters Patent of 9th January 1874,
No. 124) has hitherto been attended with a serious defect, namely, that the pressure
of the filling machine on the stream of gutta percha which flows therefrom into the
mould acts in the mould upon the wire and forces the wire in the direction of such
pressure, thereby taking it out of the central position which it ought to occupy.
Now the object of this present Invention is to overcome this defect, and in other
ways to improve the method of jointing telegraph conductors. For this purpose I
employ a mould of metal or other suitable material (and by preference thin sheet
zinc) having holes formed at various parts of its circumference so that the gutta
percha from the filling machine which fills a chamber in which the mould is situated
may enter the mould from all sides through the said holes; thus all tendency of
the wire to be deflected out of its central position by the pressure of the gutta
percha is prevented while all air readily escapes.
Having stated the nature of my Invention I proceed to describe the manner in
which I prefer to carry it into effect in a single wire conductor for instance. Each
of the two conductors to be united having had its wire made bare at the end for a
distance of, say, half an inch, I scarf the wire ends, place the scarfed parts together,
and twist them with the aid of a pair of pliers, I then unite them by solder, or any
other method of uniting the copper may be used.
The conductor with the wires united as just explained is then placed in my
perforated mould, which must be sufficiently long to cover not only the bared
portion of the wire but also a part of the conductor at each side of the bared
portion to prevent the action of the hot gutta percha interfering beyond the
distance wished. The perforated mould is by preference cylindrical, and of a
diameter only slightly larger than that of the covered conductor; or it may be
nade bulging or larger at that part which comes over the jointed portion of the

page_text: wire. In order to enable it to be readily placed on the conductor I generally make.
it of two half cylinders, which are flanged longitudinally, so that by the flanges
bearing against each other the half cylinders may be retained in position. I prefer
that the holes in the mould should be fine and numerous and extend all over its
surface, but a good union will be made so long as the holes are sufficiently dis-
tributed over the mould to prevent unequal pressure upon the wire. The portion
of the joined conductor intended to be covered with gutta percha having been
placed in the mould the mould is now placed in a chamber, which may with advan-
tage be cylindrical. The chamber is made in halves or parts opening on a hinge or
otherwise, so as to allow the perforated mould with the conductor to be placed
therein (after which the chamber is closed); and it has an aperture at each end
rather larger than the diameter of the mould, the ends of which project through these
apertures. One part of the chamber is in communication with a filling machine,
which I prefer should be composed of a screw working in a tube, to which the
gutta percha is supplied through an opening at the top. By rotating this screw
when the gutta percha is heated so as to be of the consistence of thick paste it
forces the gutta percha in a continuous stream or streams through one or more
As soon
apertures in the end of the tube into the chamber containing the mould.
as the chamber becomes filled the gutta percha passes in fine streams or threads
through the perforations in the mould into the interior thereof, covers the bared
portion of the conductor, and at the same time makes a perfect union with the
previous gutta percha covering at each side of the bared portion. In practice I
find it of advantage to shift the mould together with the conductor during the
process of making the joint; that is to say, I first have in the chamber the middle
portion of the mould which surrounds the bared portion of the wire, then when I
find the gutta percha exudes through the perforations in that portion of the mould
which is outside the chamber I shift the mould with the conductor so as to bring
within the chamber the portion at one side of what was originally the bared portion
of the wire, and after this portion has been acted upon I bring the portion at the
other side of the originally bare portion under operation. In this way I find that
I obtain a perfect union or "marrying "between the old gutta percha covering and
the new, as the old portion becomes soft owing to the heat of the new portion from
the filling machine. Or instead of, as described, first acting upon the bared portion,
and then successively upon the covered portions adjoining the bared portion, I may
act upon one or both of such covered portions before acting upon the bared
portion.
I now open the chamber and remove the mould and conductor therefrom, and
when the gutta percha has had time to set or harden I take off the mould, and this
may be readily done when made of thin metal by stripping it off with the aid of
pliers; or the same mould may be used over and over again if properly constructed
for that purpose, as will be well understood. The joint in the insulated conductor
may be then reduced to the diameter of the rest of the conductor, and smoothed by
means of sandpaper or otherwise. Or if preferred the mould may be left attached
to the joint.
Although I prefer to employ a filling machine composed of a screw working in a
tube, as before described, other arrangements wherein pressure is made to act upon
the gutta percha when contained in a confined chamber may be employed for
filling the chamber and mould; for example, a piston working in a cylinder may
be used, the piston in its reciprocating motion forcing the gutta percha through an
aperture or apertures in the end of the cylinder into the chamber.
The gutta percha may either be softened by heat to the necessary degree before
being put into the filling machine, or this machine may be heated by a spirit lamp
or otherwise, but the gutta percha must be of the right temperature and be kept at
that temperature during the operation, as will be well understood.
Although I have hereinbefore spoken only of gutta percha as the insulating
material the Invention also applies to forming joints in conductors covered with
other plastic insulating material or materials, such for example as india rubber or

page_text: a mixture of gutta percha and india rubber, which become soft under the influence
of heat and again harden when cold.
The same apparatus and method of covering the wire which I employ to cover a
joined part of the wire may whenever it is necessary be employed in covering-any
wire or part of a wire that needs to be carefully covered. In cases where a fault
occurs in covering a wire originally, or where it occurs in an injured part of a
--covered-wire, the part where the fault occurs is covered and efficiently joined up by
applying a coating in that part which effects or restores the complete union or con-
tinuity-of-the-insulator.
I claim under the first part of my Invention my improved process or mode of
treating gutta percha or other like gums by first cleansing the material and driving
off water, and then expelling the air from the cells containing it in such a manner
that I am enabled to dispense with the operation of mastication, substantially in
the manner above described.
I also claim the improved process of consolidating the prepared or partially
prepared material by turning it over and twisting it by the action which I have
called spinning, so as to bring the material into a fit state for being applied as an
insulator for telegraph wires, substantially as herein described.
I also claim the manufacture of covered or insulated telegraph wire by applying
to such wire by means of any ordinary covering apparatus insulating material,
prepared and consolidated substantially in the manner hereinbefore described.
Also I claim under the second part of my Invention,―
1. Making joints or unions between lengths of insulated telegraphic conductors
by placing the joined conducting wire in a perforated mould, through the orifices
of which the insulating material is pressed from a heated closed chamber by pressing
apparatus in such a manner as to insure that the material is distributed around and
along the joined parts of the wire, substantially in the manner herein before
described.
2. My improved apparatus for applying insulating material to covering parts of
telegraphic wires, wherein a perforated mould is employed for enclosing the part of
the conductor intended to be covered in combination with a surrounding chamber,
which is heated and filled to excess with the insulating material in a plastic state,
pressure being applied to the material by any suitable means in such a manner as
to force it through the orifices in the perforated mould and distribute it around and
along the wire, substantially as described.
In witness whereof, I, the said Edwin Thomas Truman, have hereunto set
my hand and seal, the Second day of May, One thousand eight hundred and
seventy nine.
EDWIN THOS. TRUMAN. (L.S.)