IMPROVEMENTS IN MOULDING OR APPLYING INDIA-RUBBER AS THE BASIS OF ARTIFICIAL TEETH. AND IN APPARATUS FOR THE SAME
Year: 1860

page_text: LETTERS PATENT to Henry Andrew Dewar, of Union Street, Aberdeen,
North Britain, M.D., for the Invention of "IMPROVEMENTS IN MOULDING
OR APPLYING INDIA-RUBBER AS THE BASIS OF ARTIFICIAL TEETH. AND IN
APPARATUS FOR THE SAME."
Sealed the 29th June 1860, and dated the 2nd January 1860.
PROVISIONAL SPECIFICATION left by the said Henry Andrew Dewar
at the Office of the Commissioners of Patents, with his Petition, on the
2nd January 1860.
I, HENRY ANDREW DEWAR, of Union Street, Aberdeen, North Britain, M.D.,
do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN
MOULDING OR APPLYING INDIA-RUBBER AS THE BASIS OF ARTIFICIAL TEETH, AND IN
APPARATUS FOR THE SAME," to be as follows:-
I employ the ordinary apparatus used in the application of india-rubber as
the basis of artificial teeth with some slight modifications, and apply thereto
apparatus according to and necessary for carrying out my Invention. 1 place
the cast of the jaw requiring teeth in the lower part of the apparatus or
moulding flask, and on this I set the artificial teeth as usual, but instead of
adjusting them with gutta percha and wax, I do so with wax alone; this done
I now place the middle part of the flask in position, and run it full of plaster,
but before doing so I place a stick of wax in connection with the wax of the
Price 8d.]

page_text: set contained in the flask. This stick of wax stands up and projects through
a hole which I form in the top of the flask. Two small holes are also formed
in the intermediate piece of the flask, and I place therein two or more pieces
of wire, the ends of which in one direction touch the wax of the set. while the
ends in the opposite direction project through the flask. The cover being
placed on the flask. & the whole secured together. I turn it upside down on a
plate or receiver, & place it in an oven at a sufficient temperature to melt the
wax setting. which runs out by the hole formed by the wax stick before
mentioned. I now remove the small wires. and place the flask while still hot
in connection with my apparatus, with which I fill in and pack the india-
rubber in the mould so obtained.
This apparatus consists of a cylinder fitted with a piston, worked by a screw
lever. or other suitable power; the cylinder is furnished with a jacket. in which
I admit steam or other heating medium. I place the prepared india-rubber
(the same as usually employed for the purpose) in the cylinder, and allow it
sufficient time to be reduced to the softened or plastic state necessary. This
apparatus being suitably fixed to the flask, and having the opening in the
bottom of the cylinder in coincidence with the hole in the top of the flask.
I then force down the piston of the cylinder. thus forcing the india-rubber to
enter the mould. and so assume the form of the set required and as vacated by
the wax when the india-rubber is forced out at the small holes or gates before
mentioned the packing is complete. I then remove the packing apparatus.
and apply the ordinary incans of holding the flask together. at same time apply-
ing a plug pad to the hole in the top to stop it, and against which the binding
screw of the stirrip or fixing strap abuts. The moulded set or base is then
ready to be vulcanized, as well understood.
Instead of melting the wax out of the mould in an oven, it may be effected
by currents of hot air. or steam, or by a hot alkaline solution being forced
through.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of January, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Henry Andrew Dewar, Her special licence that I, the said Henry
Andrew Dewar, my executors, administrators, and assigns, or such others
as I, the said Henry Andrew Dewar, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time and
at all times thereafter during the term therein expressed, should and lawfully
might make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for IMPROVEMENTS IN MOULDING OR APPLYING INDIA-RUBBER AS THE BASIS OF
ARTIFICIAL TEETH AND IN APPARATUS FOR THE SAME," upon the condition
(amongst others) that I, the said Henry Andrew Dewar, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters. Patent.
NOW KNOW YE, that I, the said Henry Andrew Dewar, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained; in and by the follow-
ing statement, reference being had to the Sheet of Drawings, hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
I employ ordinary apparatus used in the application of india-rubber as the
bases of artificial teeth with some slight modifications, and apply thereto
apparatus according to and necessary for carrying out my Invention. I place
the cast of the jaw requiring teeth in the lower part of the apparatus or
moulding flask; and on this I place the artificial teeth as usual, but instead of
adjusting them with gutta percha and wax 1 do so with wax alone; this done
1. now place the middle part of the flask in position, and run it full of plaster,
but before doing so I place a stick of wax in connection with the wax of the
set contained in the flask. The stick of wax stands up and projects through
a hole which I form in the top of the flask. Two small holes are also formed
in the intermediate piece of the flask, and I place therein two or more pieces
of wire, the ends of which towards the centre touch the wax of the set, while
the other ends project through the flask. The cover being placed on the flask,
and the whole secured together, I turn the whole upside down on a plate or

page_text: receiver and place it in an oven at a sufficient temperature to melt the wax of
the setting, which runs out by the hole formed by the wax stick before
mentioned. I now remove the small wires and place the flask while still hot
in connection with my apparatus, with which I fill in and pack the india-
rubber in the mould so obtained.
This apparatus consists of a cylinder fitted with a piston worked by a screw,
lever, or other suitable power; the cylinder is furnished with a jacket, in which
I admit steam or other heating medium. I place the prepared india-rubber
(the same as usually employed for the purpose) in the cylinder, and allow it
suflicient time to be reduced to the softened or plastic state necessary. This
apparatus having been suitably fixed to the flask with the ejection aperture in
the bottom of the cylinder in coincidence with the opening in the top of the
flask, then force down the piston of the cylinder, thereby forcing the india-
rubber to enter the mould, and to assume the form of the setting required and
as vacated by the wax; when the india-rubber is forced out at the small holes
or vents before mentioned, the packing is complete. I now remove the pack-
ing apparatus, and apply the ordinary means of holding the flask together, at
same time applying a plug or pad to the hole in the top to stop it, and against
which the binding screw of the stirrup or fixing strap abuts. The moulded
set or base is then ready to be vulcanized, as well understood.
Instead of melting the wax out of the mould in an oven, as before described
it may be effected by currents of hot air or steam, or by means of a hot
alkaline solution forced through the flask.
DESCRIPTION OF DRAWINGS.
The annexed Drawing represents apparatus complete for the application of
india-rubber as the basis of artificial teeth according to my Invention.
Fig. 1 represents the whole of the apparatus in position, mounted on a
suitable bench or table A, A. B. B, is the wrought-iron frame, fixed in a
vice C, or it may be otherwise secured; this frame B has a boss at each end
fitted with screws a, b; on the screw a a plate or disc d is fitted; this may be
moved towards or from its supporting boss by turning the screw therein, and
as may be required; D is the flask containing the set of teeth to which the
base is to be applied; it is of the ordinary form. and is clamped between
plates &f, seen separately at Figs. 2 & 3; E is the cylinder containing the
rubber to be introduced, the rod g of whose piston is connected with or has
formed on it a screw b, fitted to the other boss of frame B; this screw is
furnished with a suitable winch handle or lever, whereby to communicate

page_text: rotatory motion to the screw, & cause the piston to traverse in its cylinder.
As before mentioned, the cylinder E has a jacket casing, in which steam is
introduced to dissolve or render plastic the india-rubber. In order to supply
the steam, F is a small boiler, which I place on a Bunsen's burner and stand G,
having a suitable supply of gas by pipe h. The steam generated in F passes
by pipe t, and circulates in the jacket of the cylinder; see section, Fig. 11.
H is a small portable 'oven, with a double bottom, which I also mount when
required on the burner and stand G. This completes the whole apparatus
necessary.
i
In proceeding to form the vulcanite base for a set of teeth, I take the cast
of the jaw to be fitted in the wax in the ordinary way; I then take a model in
plaster from such wax mould, and set it in plaster contained in the lower
part of the flask, all as in ordinary. I now mount on the plaster cast a
model of the vulcanite base to be produced. This model I form of wax alone,
or analogous material suited for the purpose. After fitting the teeth thereto,
and also fitting it accurately to the mouth from which the cast was taken, I
place it in position on the plaster cast in the part 1 of the flask, and then place
part 2 of the flask in position, and place two or more wires i, k, (see Fig. 4,
which is a section of the flask across the jaw of the wax model,) in contact
with the wax at the one end, while the other end projects through holes in the
flask. I also erect a stick of wax, or it may be a thick wire
the model, as seen also in Fig. 4; this being done I run
from the wax of
the flask full of
plaster, and then place on it the top or cover 3. The wax model, together
with the set of teeth, will now be embedded in the plaster contained in
the flask; when the plaster is sufficiently set and dry, I withdraw the wires
i, k, & l, and invert the flask in a suitable, receiver, and place it in oven H, in
which it is heated till all the wax runs out by the gates or holes produced by
withdrawing the wires; any wax not finding its way freely out by the gates
will be absorbed by the plaster: the gates should however be in such position
and of sufficient number as to insure the necessary egress for the wax. The
wax being so removed, the teeth will be left in the plaster, while the space or
spaces left by the wax will be void, to fill which with india-rubber is now the
object to be effected. To effect this I place the flask between the plates e & f,
binding them together by means of screw dogs m, m, m. In the meantime
the cylinder E is filled with india-rubber or combinations thereof with other
material. For this purpose the piston and its rod are withdrawn, and the
cylinder slewed round on the bolt a. on which it is mounted. Having so
charged the cylinder with india-rubber, and heated it by the steam from

page_text: boiler F, I return the piston to position and fix the cylinder in position in line
with the frame B. 1 now bring up the flask D by means of screw a, until the
flask presses hard against the nozzle p of the cylinder: the nozzle is of the same
diameter, and opposite to the hole in the cover (see Fig. 5). I now, by
means of a winch handle and screw on rod g, cause the piston to force the
plastic rubber into the hole vacated by the stick of way or large wire I, from
whence it distributes itself throughout the whole area originally occupied by
the wax model and also permeating the interstices or holes formed, in the
teeth, in order to secure them; by this means the rubber will first take the
exact form of the wax model, and this being complete it will escape at
wires i, k, this escape indicating
The flask is now removed from
the gates formed by the withdrawal of the
that the operation of packing is complete.
the cylinder, a plug r placed in hole q. and the whole bound, together by the
stirrup 8, as seen at Fig. 6. The flask is then placed, in, the oven, and kept at
a sufficient temperature to render the rubber hard, as well understood, as
applied to like purposes.
Figs. 7, 8, 9, & 10 represent another arrangement of the flask. Fig. 7
represents it complete. in which it will be seen the hole, q is at the side instead
of in the cover of the flask, while the dogs m are two in number, and jointed
to the bottom or part 1 of the flask seen in plan, Fig. 8, instead of being
separate, as before. Fig. 9 is the part 2, while Fig. 10 represents the top or
cover. The operation is the same with this flask, excepting that the hole or
gate whereat the plastic india-rubber is introduced is in the plane of the jaw
instead of perpendicular thereto, as before described. Small gates are also
formed by the introduction of two or more wires i, k, at, suitable, points to
insure the object desired.
Instead of a piston being used to force the india-rubber into the mould,
a screw or other means of expressing the plastic material may be adopted.
Figs. 12 & 13 represent end and side views of a small gas soldering or
fusing iron which I make use of in moulding and forming the wax and rubber
material. It consists of a 'small hollow copper bit v, supported on an
adjustable stem w, whereby it can be brought nearer to or further from the
small gas jet x, issuing from pipe y. traversing the handle z. This pipe is
furnished with a stop-cock to regulate the emission of gas which is supplied
through flexible pipe y', which affords all necessary freedom for handling the
instrument. The small gas jet from y playing into the hole of the hollow
bit raises and keeps it at the temperature required.
Fig. 14 is another form of hollow bit, to be substituted for for v, w; this is

page_text: simply a small hollow copper cone. into the base of which the gas jet is
directed.
Having described the nature of my Invention, and the manner of performing
the same, declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent, is, preparing the mould for the
reception of the india-rubber base of the teeth with gates or inlet and outlet
apertures, as herein-before described, and the forcing and moulding therein the
india-rubber material in a plastic state by pressure & apparatns, as herein-
before described.
In witness whereof, I, the said Henry Andrew Dewar, have hereunto set
my hand and scal, this Twenty-ninth day of June, in the year of
our Lord One thousand eight hundred & sixty.
HENRY ANDREW DEWAR. (L.S.)