Improvements in Tools, Instruments, or Apparatus to be used in Dentistry.
Year: 1893

page_text: Date of Application, 30th Jan., 1893-Accepted, 18th Mar., 1893
COMPLETE SPECIFICATION.
Improvements in Tools, Instruments, or Apparatus to be used in
Dentistry.
JOHN EDWIN HIBBERT of 44 Broad Street, Pendleton Salford, Manchester
in the County of Lancaster Surgeon Dentist do hereby declare the nature of
this invention and in what manner the same is to bo performed, to be particularly
described and ascertained in and by the following statement :—
In dentistry an impression of the mouth is first made in suitable material, from
which a mould is made in plaster of paris.
The wax plato is then fitted to this plaster mould and the teeth are secured to
the wax for which purpose an instrument for softening and shaping the wax is used
and it is to this tool or instrument that the first part of my invention applies.
Hitherto an instrument for this purpose of suitable shape has been used formed
of metal, which has been heated by being held in a gas flame or has been otherwise
heated, at intervals; according to my invention I form this tool or instrument by
a tube somewhat similar to a "blow pipo," to ono end of which an clastic or flexible
indiarubber tube is attached which at its other end is connected with a gas supply
pipe, the gas from which is regulated by a tap. The other end of the tube (which
has a small outlet) is bent on one side to some extent so that when the gas issuing
from it is lighted the flame will play upon a thin triangular plate of metal in an
inclined position in relation to the axis of the tube, in which triangular plate there
is a hole to admit air to pass and meet and mix with the gas, thus forming a
"Bunsen" heating flame.
The triangular plate is or may be attached to or formed upon a metal shank that
is made to clip the end of the tube. Thus arranged, the operating part of the
instrument is always kept heated and ready for use when the gas is turned on and
lighted.
When the mould is prepared (in which the instrument last described is or may
be used), it is put into one part of a "flask," and is secured therein by means of
plaster of paris, and then the other part of the flask is put on, and the empty space
left within the flask is filled with plaster of paris and the lid is then put on and
screwed up, after time has been allowed for the plaster to set, the flask is separated
at the proper division, and the wax is melted out, and is replaced by soft vulcanite
or celluloid or other suitable material and then the flask is warmed up and screwed
tight again and is ready for the vulcanizing process.
"
The second part of my invention relates to an improved construction and combi-
nation of the flask above referred to. In ordinary flasks as hitherto used, the
pressure is put on them in such way that the lid may be bent or bulged to some
extent one way or the other according to the means employed, thus throwing the
mould out of shape, but by my invention the flasks are made strong and are s0
arranged and combined that when the pressure is put on, no strain tending to bend
the lid or distort the moulds comes upon the flask, and the parts forming it are
guided and made to fit one into the other with great accuracy and firmness; by
means of tubular projecting guides more or less conical on their exterior (or their
equivalents) through which tubular guides the screws pass that clamp and hold the
parts of the flask together.
Fig. 1, is an-edge view and Fig. 2, a front view of the tool according to the first
part of my invention. a is the metal tube like a blow pipe with its end a' turned a
little to one side; b is the flat triangular plate formed on a shank b', having clamps b*
to grasp the tube; 6 is the hole for air to pass towards the gas jet issuing from
the nozzle a', and playing upon the flat triangular plate. To the larger end of the
tube a one end of an indiarubbor or flexible tube o is attached, the other end of

page_text: which is connected with any suitable gas supply pipe having a regulating tap,
which supply pipe is preferably about vertically ovor the place where the tool is to
be used.
Figs. 3 to 7, inclusive, illustrate the improvements in finsks according to the
second part of my invention.
Fig. 3, is a section through the flask when screwed together.
Fig. 5, is an edge view, and Fig. 7, is a plan or top view of the flask scrowed
together.
Fig. 4, shows an edge viow of the three parts forming the flask when separated
• from each other, and
Fig. 6, is a view looking inside of the bottom or lower part of the flask.
d, is the bottom, d' the middle and d, the lid of tho flask.
The flask is screwed together by three set screws or bolts e, each passing through
a hole in the lid ď, one in the middlo part d', and into the bottom part d, into which
the screws are screw tapped.
To insure accurate junctions between the parts, there are three tubular guides, dª³,
formed upon the bottom part d of the flasks, round the screw or bolt holes, and the
exteriors of these tubular guides are cylindrical for a short length and then
conical, as shown best in Fig. 4.
5
10
1
These guiding projections fit into the holes in the middle part , of the 2
flask.
There are also similar tubular but shorter guides d', round the holes for the
screws or bolts in the lid d', to also fit the holes in the middle part d' of the flask.
Fig. 8, is a sectional view showing how each set screw passes through hole for it
in the lid, middle part d³, and screws into the bottom of tho flask d.
Fig. 9, shows another mode of screwing the parts of the flask together, and
Fig. 10, illustrates another mode, the bolts e, in this case, having a sorow tapped
hole in its end to screw upon a sorowe, screwing through a threaded hole in the
bottom part d of the flask.
When required, the screws or screws with cone points may be made to sorew from 3
the underside of the flask, the points upward to act as guides when all the parts of
the flask do not require to be screwed together, and it is used in a press.
I do not confine myself to three bolts, two may be used, or more than three each
hole for the bolts having the guiding projections d³ and dª.
Having now particularly described and ascertained the nature of my said inven- 8
tion and in what manner the same is to be performed, I declare that what I
olaim is :
1. The tool or instrument heated by a gas flame substantially as and for the
purpose herein before described and illustrated by Figs. 1 and 2, of the drawings.
2. The combination of flasks having tubular guides with set scrows, or bolts, 4
substantially as and for the purpose hereinbefore described and illustrated by
Figs. 3 to 8 inclusive of the drawings.
3. The combination of flask substantially as and for the purpose herein before
described and illustrated by Figs. 3 to 7 inclusive of the drawings when modified as
herein before described and illustrated by Figs. 9 or 10 of the drawings.
Dated the 28th day of January 1893.
4
PETER J. LIVSEY,
Agent.