Note: Descriptions are shown in the official language in which they were submitted.
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B~CKGROU~D OF THE INVENTION
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1. Field of the Invention
The invention relates to ~oundry practice, and more
particularly to vacuum metal die-casting apparatus intended
preferably for producing precision castings from refractory and
highly reactive metals and alloys, such as those based on
titanium or zirconium.
2. Description of the Prior Art
British Patent Specification No. 914,508 discloses a
me~al die-casting apparatus which comprises a frame-mounted
air-tight housing common to both a melting and a casting
chamber. Enclosed in said common housing are two stationary
vertical plates interconnected by guide columns. Mounted in
the guide columns is a mobile plate provided with a reciprocat-
ing drive means. Arranged inside said air-tight housing is an
electrode holder mounted over a crucible for rotation about a
horizontal axis and provided with a drive means for actuating
said rotation.
Underneath the crucible is a funnel placed in the
pouring orifice of a pressure chamber housing.
The pressure chamber housing is built into a stationary
plate which carries one half of a die, the second half thereof
being secured to a mobile plate. The pressure chamber incor-
porates a means for forced supply of metal into the die, said
means being basically a piston secured to a piston rod of a
hydraulic cylinder.
It is a makker of practical knowledge that when metal
is forced into the die, there is no sufficient rigidity of
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connection between the two hal~-dies so that ~lash is ~ormed
at the parting planes of the die, the casting then losing in
accuracy of shape.
Further development of machine-building industry
breeds higher demands for a lar~e amount of metal die-cast
blanks. Particularly severe problems are encountered in known
apparatus for die casting precision blanks from titanium- or
zirconium-based alloys. A solution to these problems is a
currently central necessity.
SUMM~RY OF THE INVE~TIO~
It is, there~ore, an object of the invention to pro-
vide a vacuum metal die casting apparatus which will improve
the quality of castings.
Another no less important object o~ the invention is
to enhance the operating reliability of such apparatus.
These and other objects are attained by the provision
o~ a vacuum metal die casting apparatus comprising a frame
whereon are mounted two stationary vertical plates interconnec-
ted by horizontal guide columns wherein is accommodated a
mobile plate carrying one half of a die, the second half o~ said
die being rigidly connected to a stationary plate wherein are
built a pressure chamber housing and a die gate both communicat-
ing with the die cavity, and having a means for a forced supply
of metal through the pressure chamber into the die, according to
the invention, one o~ the hal~-dies being held in position by a
die holder telescopically connected to a casting chamber housing
rigidly attached to the stationary plate and provided with air-
tight seals and with a viewing port.
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As the casting chamber housing is built of telescopi-
cally connected parts rigidly attached to vertical plates, it
accurately positions th~ mobile plate when the liquid metal is
forced into the die. Air-tight seals make it possible to remove
castings from the cavity of the die without depressurizing the
apparatus, to reduce the overall dimensions of the vacuum cham-
ber and to locate externally with respect to the latter both a
drive means for actuating the mobile plate and a thrusting
hinged mechanism. The viewing port in the housing facilitates
the operation of the die and makes it possible to check visually
the casting of metal blanks and their quality.
It is advantageous to attach a means for cleaning the
die cavity to the vacuum casting chamber housing with the aid
of a spherical pivot and to form said means with a rod carrying
a detachable actuating tool. This makes possible to clean the
castin~ die without depressurizing the casting chamber and thus
improves the quality of castings, i.e., makes them as close as
is practically possible to the ideal shape.
BRIEF DESCRIPTIO~ OF TME DRAWI~GS
~hese and other objects and features of the invention
become readily apparent from one embodiment thereof which will
now be described by way of example with reference to the
accompanying drawings, in which:
FIG. 1 is a side elevational view of the apparatus
with exploded views and a partial longitudinal cross-section
along a vertical plane;
FIG. 2 is the same part of the apparatus, top plan
view with a partial longitudinal cross-section along a horizontal
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plane.
DESCRIPTIO~ OF TEE PREFERRED EMBODIME~T
A metal die casting apparatus has a frame 1 (FIG. 1)
whereon are rigidly attached two vertical plates 2 and 3 inter-
connected by horizontal guide columns ~ (FIG. 2) wherein is
mounted for reciprocation under the action of a drive means 6
a third mobile plate S.
Rigidly mounted on the stationary plate 3 (FIG. 1) is
an air-tight housing 7 of a vacuum casting chamber 8. Said
plate 3 separates the vacuum casting chamber 8 of the apparatus
from a vacuum melting chamber 9. A housing 10 of a pressure
chamber 11 is built into the vertical stationary plate 3 and
connected to a gate 12 communicating with the pressure chamber
11 and a cavity 13 of the die 14.
The pressure chamber 11 is fitted with a means 15 for
forced supply of metal into the die 14. Said means 15 incox-
porates a hydraulic cylinder 17 with a rod 18 entering the
pressure chamber 11, said hydraulic cylinder being supported
by a leg 16~
One half-die 19 is rigidly fastened to the stationary
vextical plate 3, whereas the second hal-die 20, to a die
holder 21 rigidly mounted on the mobile plate 5.
The improvement in the vacuum die casting apparatus,
according to the invention, consists in that the vacuum casting
chamber 8 has its own air-tight housiny 7 attached, on the one
hand, to the stationary plate 3 and telescopically connected, on
the other hand, to the die holder 21 set rigidly on the mobile
plate 5. Air-tight seals 22 are provided at the joints of the
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housing 7~
The housing 7 of the vacuum casting chamber 8 is
fitted with viewing ports 23 ~FIG. 2) and with ports 25 incor-
porating covers 24 for servicing the die 14. A hopper 26 is
provided or storing finished metal castings (FIG. 1).
A hydraulic cylinder ~7 with a rod 28 cooperati.ng
with a pusher 29 entering the cavity 13 of the die 14 and
facilitating the removal of a finished metal casting (not shown
on the drawings) is attached, externally with respect to the
vacuum casting chamber 8, to the vertical mobile plate 5.
For cleaning the cavity 13 of the die 14, the appara-
tus is provided with a means having a rod 31 with a detachahle
actuating tool 32, e.g., a scraper, said means being attached to
the housing 7 of the vacuum casting chamber 8 with the aid of a
spherical pivot 30.
The vacuum metal die casting apparatus according to
the invention operates as follows.
Vacuum is built up in the vacuum melting 9 (FIG. 1)
and the casting 8 chambers by means of a vacuum plant (not shown
on the drawing). The drive me~ns 6 is energized to actuate the
plate 5 and ensure an air-tight closing of the halves of the
die 14.
The apparatus is supplied with electric current to
melt an amount of metal sufficient to cast a specified number of
castings, the liquid metal then being transferred to the pressure
chamber 11, whereupon a hydraulic cylinder 17 is energized, its
rod 18 forcing a portion of metal into the cavity 13 of the die
14. This portion of metal is held for a predetermined time in
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the die until the cas ting solidi~ies.
A ~inished casting is removed from the cavity 13 of
the die 14 by energizing the drive means 6 to move the plate 5
in the reverse direction and so open the half-dies of the die
14, the die holder 21 re~aining within the enclosure of the
vacuum seals 22 of the casting chamber 8. When the mobile
plate 5 is backed away from the stationary plate 3, the
hydraulic cylinder 17 is energized, its rod 18 pushes out of
the gate 12 the solidified excess portion of the metal, and the
casting, from the half-die 19 o~ the die 14 built into the
stationary plate 3. Should the casting fail to ~all out of the
die 14, it is pushed out by the pusher 29 which is actuated by
the rod 28 of the hydraulic cylinder 27, the casting then slid-
ing into the hopper 26 of the vacuum casting chamber 8.
~ ext, the cavity 13 of the die 14 is cleaned of
splashes of metal by a scraper 32 fastened to the rod 31 of the
aforesaid cleaning means and reaching any area of said cavity.
Once the half-dies of the die 14 are cleaned, the
latter is closed by the action of the drive means 6 which moves
the mobile plate 5 toward the stationary plate 3~
This terminates the operating cycle of the apparatus.
To repeat the operating cycle of the apparatus, it is not
necessary to depressurize the latter, since, as has been experi-
mentally found, the apparatus, according to the invention, can
operate faultlessly for a Long period of time and ensure a high
quality of castings.
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