Year: 1887

page_text: Date of Application, 26th Apr., 1887
Complete Left, 23rd Jan., 1888
Complete Accepted, 26th Apr., 1888
I, GEORGE HENRY SALT, of 46, Cromwell Terrace, Newport Road, Middlesbrough,
in the North Riding of York, Dental Surgeon, do hereby declare the nature of this.
invention to be as follows:-
My apparatus consists of two outer and one middle or intermediate parts, arranged
with grooves or slots, and projections or pieces, so that it may be used for one set
of teeth, with the two outer parts, as in an ordinary flask, or by the insertion of the
middle or intermediate part between the two outer parts, it may be used for two sets
of teeth, at will.
Dated this 25th day of April 1887,

page_text: I, GEORGE HENRY SALT, of 46, Cromwell Terrace, Newport Road, Middlesbrough,
in the North Riding of York, Dental Surgeon, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
Up to the present, it has been usual to vulcanise one set or case of teeth in one
flask, consisting of two parts.
The object of this invention is to vulcanise two sets of cases of teeth in one flask,
or in other words, to make one flask serve the purpose of two, thus effecting a
considerable saving in first cost, time, material and space.
In the ordinary flask, there are two parts, forming the top and bottom. In my
invention, there are three parts, consisting of two outer, and one middle or intermediate
parts, arranged with grooves or slots, and projections, pieces or tongues, so that it
may be used for one set or case of teeth, with the two outer parts, as in an ordinary
flask, or for two sets or cases of teeth by the insertion of the middle or intermediate
part between the aforesaid two outer parts, at will.
In order to render my invention more clearly understood, I annex a drawing No. 1
& final, which I now proceed to describe.
Fig. 1. shews a plan view of the outside, Fig. 2. shews an elevation, and Fig. 3.
shews a plan view of the inside of one part, marked A, which for convenience, we
will call the upper part, although, either outer part may be used as the upper or
lower part.
Fig. 4. shews a plan of the inside, Fig. 5. an elevation, and Fig. 6. a plan of the
outside of the other or lower part, marked B.
Fig. 7. shews a plan of the upper side, Fig.18. an elevation, and Fig. 9. a plan of
the under side of the middle or intermediate part marked C.
Fig. 10. shews an elevation of my flask composed of the outer or upper part A, and
the outer or lower part B, as necessary for vulcanising one set of teeth.
Fig. 11. shews an elevation of my Hask composed of the upper part A, the middle
or intermediate part C, and the lower part B, as necessary for vulcanising two sets or
cases of teeth.
On the lower edge of the upper part A are shown_projections, pieces or tongues
marked a. On the upper edge of the lower part B are shown grooves or slots
marked b, identical with the projections, pieces or tongues marked a upon the upper
part A. On the upper edge of C are shown grooves or slots marked c, identical with
the projections, pieces or tongues marked a upon the upper part A, and on the lower
edge are shown projections, pieces or tongues, marked "d, identical with the grooves
or slots marked b on the lower part B.
Inside of the middle or intermediate part C is shown a web or diaphram marked e,
for the purpose of more effectually forcing the plaster, so as to make it fill every
cavity or interstice.
Figs. 10. and 11. after what has been stated above, explain themselves.

page_text: The action of my invention, for two sets of teeth, is as follows:-
Having filled the lower part B with plaster, I press therein a set of teeth, and allow
the plaster to set hard, as is usual.
I also fill the upper part A with plaster and press into it a set or case of teeth,
afterwards allowing the plaster to set hard.
I then fit the middle or intermediate part C by means of its projections, pieces or
tongues d to or into the grooves or slots b of the lower part B, and fill it with plaster,
after which, I immediately fit the upper part A into the middle or intermediate part C,
by means of its projections, pieces or tongues a and the grooves or slots c of C,, while
the plaster is plastic, thus causing the plaster in C to take the exact form of the upper
surface of the set or case of teeth in the lower part B and the set or case in the
upper part A.
The flask after attaching the screw cramp is then ready for the furnace.
For one set of teeth, the operations are the same, only that the middle or inter-
mediate part C is omitted.
Having described the nature of my invention and explained the manner of per-
forming it, I hereby declare, that what I consider to be novel and original, and there-
fore claim as the invention secured to me by the herein-before in part recited letters
patent is,―
The middle or intermediate part (, with its grooves or slots c, and projections,
pieces or tongues d, whereby it can be used in conjunction with the upper part A and
lower part B to do the work of two flasks and by its withdrawal, tho two outer parts A
and B may be used as an ordinary flask for one set of teeth, at will.