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Патент USA US2110301

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March 8, 1938.
Filed June 6, 1936
_2 Sheets-Shéet 1'
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March 8, 1938.
Filed June a, 1936
2 Sheets-Sheet 2
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Patented Mar. 8, 1938
' 2,110,301
Emery J. La Porte, Omaha, Nebr.
Application June 6, 1936, Serial No. ‘83,881
2 Claims.
This invention relates generally to casting ap
paratus and particularly to dental casting appa
ratus for applying pressure to molten metal
being cast to force said metal into all parts of
5 the mold-cavity.
In the casting of delicate metal pieces such as
gold dental inlays, plates and the like in a mold
of refractory material the penetration of the
metal into the delicately hollowed parts of the
10 mold presents considerable di?culty on account
of the physical characteristics of the gold or
other molten metal.
The larger the casting to
be made the more difficulty is experienced.
Various means have been devised to apply pres
15 sure to the molten metal to force same into the
mold-cavity but these devices have generally
been imperfect and of little practical value to the
profession for one reason or another or they have
been too complicated and expensive and uncer
20 tain of operation for general use. For the fore
going reasons a simple, practical and efficient
machine has been needed.
It is therefore the object of my invention to
provide apparatus for instantly and accurately
25 applying pressure to molten metal to force same
into the mold-cavity of a mold, whether the
piece to be cast be large or small.
Another important object of my invention is
to provide apparatus in which such pressure
30 may be positive and in which same may be con
Another object of the invention is to provide
apparatus of this character, which, because of its
construction solves a very real problem, and
35 which because of its simplicity can be produced
Numerous other objects and advantages of the
invention will be apparent as it is better under
stood from the following description, which, taken
40 in connection with the accompanying drawings,
discloses a preferred embodiment thereof.
Referring to the drawings:
Figure 1 is an elevational View of my apparatus
completely assembled and ready for operation.
Figure 2 is a plan view of the same.
Figure 3 is a vertical section of the mold taken
on line 3—3 of Figure 1.
Figure 4 is a vertical section of the base and
forms for forming the plastic material of the
50 mold cap taken on line 3-4! of Figure 2.
Figure 5 is a partial vertical section of the
mold cap without plastic material therein.
Figure 6 is a vertical section of a mold with the
mold cap thereon in position for applying pres
55 sure to the molten metal in the mold.
(C1. ZZZ-57.1)
Referring more particularlyto the drawings,
which illustrate a preferred embodiment of. my
invention, reference numeral Ill indicates the
base of the apparatus, said base being preferably
of metal and
having todepending
support same.
legs ll A
rigid 5
upright or post l2 extends upwardly of the base
and is also formed integrally therewith, said up
right having a horizontal extension l3 terminat
ing in an enlarged vertical portion M having a 10
vertical opening therethrough in which is slid
ably received a plunger l5, normally held in its
upward position by a spring I3 abutting at its
lower end on the top of portion #4 and at its up
per end against a washer ll secured to the 15
plunger l5 by a pin Hi. The lower end of the.
plunger I5 is provided with a shoulder l9 adapted
to limit the upward movement thereof.
Means for actuating the plunger l5 comprises
an actuating or pressure arm 26) pivoted to the ~ '20
upper end of the plunger H3 at 20a interme
diately of its ends. Said arm is provided with a
handle 2| at its free end and is pivoted at its
opposite end at 20b to the swingable end of a link
22, said link 22 being also pivoted at 23 to a pivot ‘ 25
support 24 extending forwardly of the portion l4.
Below the plunger, in axial alignment there
with, a mold is removably mounted, said mold
comprising a bottom member 25 having a de
pending pin 26 removably received in an open~ 30
ing in the base i (3 provided therefor, said bottom
member 25 is also provided with an upturned
flange 2'! within which is received a cylindrical
casing 28 ?lled with a suitable investment 29 of
refractory material in which is a mold-cavity of
the exact size and shape of the desired metal
casting, shown in the drawings as ?lled with
metal 30. There is the customary depression 3|
formed in the top of the investment and a com
paratively small sprue opening, ?lled with metal
32, which leads down into the mold-cavity from
the bottom of the depression 3!. A small amount
of surplus metal 33 remains in the bottom of the
depression 3|.
Above the mold, and in axial alignment there- .
with, is a cap 34 having an upwardly extending
pin 35 ?xed removably in an opening in the
plunger rod l5 provided therefor, said cap 31%
having a downwardly extending flange 36 within
which the upper end of .the casing 28 is received. ’
‘Within the cap 34 is a plastic material 31 such
as fuller’s earth, the inner surface 38 of which
is concave and provided with an annular, mar
ginal portion 39, the inner side of which is hori
zontal, said portion 39 being of the same hori
zontal con?guration as the upper edge of the
casing 28. The con?guration of the plastic ma
terial facing the ‘mold is formed by placing a
quantity of said material in the cap 34 and then
pressing same over a suitable form, three sizes
plied by my apparatus to the molten metal, cast
ings of relatively large size, such as dental plates,
may be successfully made with a reduction of
failures to such an extent as to almost eliminate
same. No other apparatus has been placed on
of said form being shown on base I0 and num
the market that will e?ect such ?ne castings
bered respectively 40, ll, and 42.
with such a small percentage of failures as can
be secured with the present invention.
Ordinarily, with other devices, several sprue
openings mustbe provided in. making large cast 10
ings but with my apparatus such large castings
may be successfully and satisfactorily made with
. point of a pin by means of which same is sup
ported in the cylindrical casing 23 while the in-; jja'risingle sprue opening and such castings, made
In using my apparatus the customary way of
forming the mold is followed. A wax impression
or pattern of the cavity. in the tooth is ?rstlmade
and this wax pattern» is then placed upon the
, vestment material 29 is poured into positionl’in" with my apparatus, are as ?ne and free from de
15 said casing. After the investment hasihardened" ' fects "as small castings.
the pin is removed and the mold is, subjected to-. ,
a su?icient amount ofheat to completely remove
It‘gisnthought that the invention and many
of its- attendant advantages will be understood
I or burn out the wax, thereby leaving‘ the‘ mold-3 " from: the‘fo'r'egoing. description, and it will be ap
cavity and the comparatively small sprue open-e , parentv that various changes may be made in the
ing leading downwardly thereto from the de-”‘
.pression 3|; The foregoing is- the conventional
way‘ of forming a mold, althoughso far as the
present, invention is concernedthe- mold can; be
formed in any desired’ manner.
form, construction ‘and arrangement of the parts 20
without departing from the spirit ‘and- scope‘ of
theinvention or sacri?cing all- of its material ad
vantages, the form’ hereinbefore' described ‘ being
merely‘ a preferred: embodiment thereof.
Having thus described my invention‘ what I 25
* Informing a casting‘ a quantity of molten gold
vor other metal must be placed‘ inxthe depression
1. In apparatus of the class described, a‘ base,
3| and some-means utilized for causing the molten
metal to '?o-w through the sprue opening‘ and‘ a mold attached to the base, said mold having‘ a
enter the mold-cavity’ before the metal coolsand cylindrical. casing with its axis vertical, said cas
hardens. To facilitate this operation the mold ing having a substantially horizontal upper edge,
is, of course, heated so that the molten metal _a cylindrical cap closed at one end‘ and: open at
will not harden when it ?rst comes into contact the other and disposed above the mold casing,
the axis of the cap coincidinguwith that of- the
According to the instant invention pressure is casing; said cap being of larger diameter than
the casing and adaptedvto» receive said casing a:
applied to the‘ molten- metal in the mold by apply
within same, plastic material in the mold‘ cap,
ing pressure-on handle 2 I.‘ which forces the plung
the surface of said plastic material: being in
er rod l5 and cap 34 down onto the ,mold,rsu?‘i
dented and provided with an annular horizontal
cient pressure being available-because of the le
ver arrangement of the pressure applying means. portion adjacent the open rim of the cap adapt-'
The-horizontal surface of portion- 39-of'the plastic ' ed to receive the upper rim of the~casing there
material ?rst comes into contact with the upper againstto form an instant seal, and power am
plifying means for applying. pressure to the‘ cap
edge of the casingplil-v and immediately and in
stantly causes a seal therebetwee'n‘. Additional ’ to ‘axially press same ontothe mold and apply
pressure on the handle compresses the air trapped pressure to the molten metal: in the mold through
air, trapped in the indentation of the plastic
in, the‘ cavity formed between the inner sur-7
face of- theplastic material 31 and the ‘surface
2. In apparatus of the class ‘described, a base,
of the depression of. the investment material 29
and such pressure is increased by the heating and . a mold attached to the base, said ‘mold having a
expanding of said trapped air; The pressure of substantially cylindrical ‘casing. with its axis-ver- ‘
the trapped air exerts pressure on the molten
metal thereby forcing. same down- through the
sprue opening and to all parts of the mold
cavity. The space, between,v the ?ange 36 of the
cap 24 and the casing 28 is small, as shown in
55 Figures 1 and 2 and the plastic material is rela
tively sti? so that said material will not squeeze
out of the cap 34 when pressure is applied to '
the molten metal in the mold.
Because of the accurate alignment and the ar
rangement of the various parts of the apparatus
positive and instantaneous pressure maybeap
plied to the molten metal in the mold and said
pressure may be controlled so that any necessary
and desirable pressure may be applied-by the
65 pressure exerted on the handle.
It has been found that because of the positive,
instant and controlled pressure that may be ap
tica-lly disposed, said casing having a substan- I "
tially horizontal upper edge; a substantially cy'
lindrical cap closed. atone end' and open at the
other anddisposed above the mold casing, the
axis of the cap substantially coinciding with that
of the casing’, said‘ capbeing of larger diameter 1‘ ‘
thanthe casing and adapted to receive'said cas
ing within same, plastic material in- the mold
cap, the surface of said- plastic material being
indented and‘ provided with an‘ annular hori
zontal portion- adjacent the open rimof the cap
adapted to‘receive the: upper rim of the casing
thereagainst to form‘ a’ seal therebetween, and
means for applying pressurev to'the cap to axially
press same ontothe mold‘ and apply pressure to
molten metal in said mold.
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