AN IMPROVED MODE OF AND APPARATUS FOR SUPPLYING PLASTIC COMPOUNDS OF INDIA RUBBER AND GUTTA PERCHA TO MOULDING OR SHAPING DIES."
Year: 1879

page_text: LETTERS PATENT to Matthew Gray, of Cannon Street, in the City of London,
•
Engineer, for the Invention of "AN IMPROVED MODE OF AND APPARATUS FOR
SUPPLYING PLASTIC COMPOUNDS OF INDIA RUBBER AND GUTTA PERCHA TO
MOULDING OR SHAPING DIES."
PROVISIONAL SPECIFICATION left by the said Matthew Gray at the Office
"AN
of the Commissioners of Patents on the 10th December 1879.
MATTHEW GRAY, of Cannon Street, in the City of London, Engineer.
IMPROVED MODE OF AND APPARATUS FOR SUPPLYING PLASTIC COMPOUNDS OF INDIA
RUBBER AND GUTTA PERCHA TO MOULDING OR SHAPING DIES."
The object of the present Invention is to supply india rubber, gutta percha, and
similar plastic compounds to moulding or shaping dies free of air and comparatively
free of moisture, and that at a uniform or unvarying pressure.
Hitherto the practice of insulating telegraph wires by means of india rubber or
gutta percha, or their compounds, has been to apply two or more coatings in suc-
cession to such wires, in order that the defects in the one coating caused by the
presence of air or moisture in the compound might be remedied by the succeeding
coating or coatings. This repetition of the process has rendered the manufacture
costly, and has not entirely removed the defects above indicated.
In like manner when moulding a cord or tube of rubber or gutta percha, or a
beading, the presence of minute particles of air produces indents on the surface and
cavities in the body of the goods, the presence of which detracts from their
value.
I now propose by the use of a new combination of well known mechanism, not
merely to remove these defects, but also to ensure such a pressure at the back of
the moulding die that the tubular or other forms exuding therefrom shall have a
uniform size and consistency.
To this end I use the ordinary cylinder, which carries the die box and is fitted
with a propelling screw for forcing the plastic material through the die, and upon
this cylinder I mount a pair of ordinary horizontal rollers, such as is now used for

page_text: making rubber cord and tube, and convert these rollers into a feeding machine for
supplying the cylinder containing the screw propeller with the plastic gum under
pressure. This is accomplished by connecting the guides at the lower part of the
horizontal rollers with the inside of the cylinder containing the propelling screw by
means of a conducting tube.
The plastic composition as it is fed to the rollers will be squeezed into the form
of a sheet, which will be contracted in its breadth as it descends, and it will
ultimately be delivered into the cylinder in the form of a cord.
During the passage of the plastic compound through this feeding apparatus the
air and moisture will be worked out. As the compound is supplied to the cylinder
at a rate proportioned to the speed of the propelling screw, a uniform pressure of
the compound against the die will be maintained; thus supposing a die to be fitted
to the apparatus for forming tubes or for coating wire, the diameter of the tube or
the thickness of the coating will remain uniform throughout the progress of the
operation.
I would remark that although I am enabled by the application of one coating to
obtain a good insulation of telegraph wires suitable for land use, yet in preparing
such wires for cables I propose to apply two or more coatings when such are con-
sidered desirable.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, and of
an Order of the Lord Chancellor, filed by the said Matthew Gray in the Great
Seal Patent Office on the 1st July 1880.
"AN
MATTHEW GRAY, of Cannon Street, in the City of London, Engineer.
IMPROVED MODE OF AND APPARAtus for SupplyiING PLASTIC COMPOUNDS OF INDIA
RUBBER AND GUTTA PERCHA to Moulding or SHAPING DIES."
The object of the present Invention is to supply india rubber, gutta perchn, and
similar plastic compounds to moulding or shaping dies free of air and comparatively
free of inoisture, and that a uniform or unvarying pressure.
Hitherto the practice of insulating telegraph wires by means of india rubber or
gutta percha, or their compounds, has been to apply two or more coatings in suc-
cession to auch wires, in order that the defects in the one coating caused by the
presence of air or moisture in the compound might be remedied by the succeeding
conting or contings. This repetition of the process has rendered the manufacture
costly, and has not entirely removed the defects above indicated.
In like manner when moulding a cord or tube of rubber or gutta percha, or
a beading, the presence of minute particles of air produces indents on the surface
and cavities in the body of the goods, the presence of which detracts from their
value.
I new propose by the use of a new combination of well known mechanism, not
merely to remove these defects, but also to ensure such a pressure at the back of
the moulding die that the tubular or other forins exuding therefrom shall havo a
uniform size and consistency.
To this end I use the arrangement of machinery shewn in the accompanying
Drawing for feeding the plastic compound to the die box.
Fig. 1 shews the machine in side clevation, Fig. 2 in plan view, and Fig. 3 in end
elevation.
In these Figures A is the ordinary cylinder, which carries at one end the die
box B, and is closed by a cover at its other end. In this cylinder is mounted a
propelling screw C for forcing the plastic material through the dic. Above this
cylinder I mount a pair of horizontal rollers D, D¹, such as are now used for making
rubber cord and tubing; these rollers, which are heated with steam or hot water,
I convert into a feeding machine for supplying the cylinder containing the screw
propeller with the plastic gum under pressure. This I accomplish by fitting between
the rollers end guides E, E, the lower ends of which approach each other and connect
with a tube E, which leads down to and communicates with the interior of the
cylinder A in rear of the propelling scrow.
The rollers D, D', have their bearings in the main frame F, which also carries the
cylinder A, and it is to a cross piece on this framing that the end guides E, E, aro.
attached by means of bolts and nuts, as shown in the Drawing. The plastic com-
position fed to the rollers will be squeezed into the form of a sheet, which will be
contracted in its breadth by the end guides E as it leaves the bite of the rolls, and
converted into the form of a cord, in which shape it enters the cylinder.
During the passage of the plastic compound through this feeding apparatus, the
air and moisture contained in the compound will be worked out by the heated
rollers, instead of as heretofore being imprisoned in the compound when that is
presented to the moulding die.
The motion for driving the rollers and the propelling screw is taken from the
main driving shaft G, to which is keyed a worm g and a spur wheel g'. The
worm g gears into a worm wheel g³ on the shaft of the screw propeller C, and
the spur wheel g¹ gears into a wheel g³ mounted on a stud axle projecting from the
framing F. Secured to this wheel is a spur wheel g of larger diameter, which
gears into and drives a wheel h on a horizontal shaft й. A worn h³ keyed upon

page_text: this shaft gears into and drives a worm wheel d on the axle of the roller D, and
this roller is connected with the rollers D¹ by means of a pair of pinions d².
By this arrangement of gearing any required rate of feed proportioned to the
efficient action of the propelling screw may be obtained.
As the compound is supplied to the cylinder at a rate proportioned to the
speed of the propelling screw, a uniform pressure of the compound against the
die will be maintained; thus, supposing a die to be fitted to the apparatus for
forming tubes or for coating wire, the diameter of the tube or the thickness of tho
coating will remain uniform throughout the progress of the operation.
The cylinder A I propose to surround with a hot water jacket in order to
maintain the temperature of the compound, and the cylinder I pierce near its
forward end to provide for the escape of air when starting the machine, and to form
a vent which will indicate the proper working of the apparatus.
The material will be conveniently supplied by hand to the feed rollers in the
form of cylindrical blocks, which will be thrust end wise between the rolls.
I would remark that although I am enabled by the application of one coating to.
obtain a good insulation of telegraph wires suitable for land use, yet in preparing
such wires for submarine cables I propose to apply two or more coatings when
such are considered desirable.
Having now set forth the nature of my Invention of "An Improved Mode
of and Apparatus for Supplying Plastic Compounds of India Rubber and Gutta
Percha to Moulding or Shaping Dies," and explained the manner of carrying the
samme into effect, I wish it to be understood that under the above in part recited
Letters Patent I claim, supplying moulding dies with plastic compounds of india
rubber and gutta percha from which the air and moisture have been worked out, in
the manner and for the purpose above described with reference to the accompanying
Drawing.
In witness whereof, I, the said Matthew Gray, have hereunto set my hand and
seal, the Thirtieth day of June, in the year of our Lord One thousand
eight hundred and eighty.