Metal founding – Means to shape metallic material – Including means to assemble mold parts
Reexamination Certificate
2002-11-26
2004-10-05
Stoner, Kiley (Department: 1725)
Metal founding
Means to shape metallic material
Including means to assemble mold parts
C164S342000
Reexamination Certificate
active
06799625
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to movable inserts for a die-casting mold and more particularly to such inserts which incorporate a movable core and still more particularly to sealing between the movable insert and the retractable core.
BACKGROUND OF THE INVENTION
An earlier invention, as described in U.S. Pat. No. 5,862,853 which issued on Jan. 26, 1999, comprises a movable insert for a die-casting mold having a cavity in which a core is mounted and slidable between a retracted position in the cavity and an extended position in which the core extends from the movable insert.
FIG. 1
is a sectional view through a prior art die-casting mold assembly, generally indicated by reference
10
for casting a part
12
having an opening or boss
14
extending therethrough which is non-parallel to a “machine direction” indicated by arrows
16
. The opening
14
is narrower at a point
17
part way along its length than it is toward either end.
The mold assembly
10
includes a movable insert
18
, a fixed insert
20
and a slide
22
. The mold assembly
10
is generally opened and closed in the machine direction. The slide
22
, as indicated by arrows
24
, is inserted and removed from the balance of the mold assembly
10
in a direction non-parallel to the machine direction.
The slide
22
, in combination with a retractable core
26
is used to form an interior surface which defines the opening
14
. The retractable core
26
forms the portion of the interior surface of the opening
14
between the movable insert
18
and the point
17
. The slide
22
forms the remainder of interior surface of the opening
14
.
As the part
12
is stripped in the machine direction, obviously it is necessary to separate and withdraw the retractable core
26
and the slide
22
from the opening
14
to enable the part to be separated from the movable insert. The slide
22
is withdrawn to the right as illustrated in the direction of arrows
24
. The retractable core
26
, as its name suggests, is retracted into a cavity
28
in the movable insert. Movement of the retractable core
26
is controlled by a locator
52
.
FIGS. 2 and 3
are sectional views illustrating the relationship between the movable insert
18
and the retractable core
26
in more detail. In
FIG. 2
the retractable core is illustrated in a retracted position in which it doesn't protrude from the movable insert
18
. In
FIG. 3
the retractable core is illustrated in an extended position in which it extends from the movable insert
18
. The extended position corresponds to the molding of the part
12
. The retracted position corresponds to the stripping of the part
12
.
It is of course necessary to prevent molten metal from seeping past the retractable core
26
into the cavity
28
to prevent the retractable core
26
from becoming “stoned” in metal (i.e., frozen in place). In the prior art arrangement, as best illustrated in
FIGS. 2 and 3
, sealing was accomplished by the mating of corresponding tapered surfaces
30
and
32
respectively on the retractable core
26
and the movable insert
18
. This arrangement however has some drawbacks. Very accurate machining is required to match the tapered surfaces
30
and
32
to give an effective seal relative to each other. Furthermore the tapered surfaces
30
and
32
must be accurately situated for the surfaces
30
and
32
to abut when the retractable core
26
is in its extended position. Any inaccuracies in the situation of the tapered surfaces
30
and
32
will either leave a gap therebetween or prevent the retractable core from fully extending. A relatively small degree of wear on the tapered surfaces
30
and
32
resulting from repeated retraction and extension of the retractable core
26
will eventually cause the seal between the tapered surfaces
30
and
32
to lose effectiveness. Once this occurs there is no simple way to restore the sealing surfaces as lapping or grinding will give a resultant seal which is only effective at a greater degree of extension of the retractable core
26
. Further extending the retractable core
26
is undesirable as it affects the location of the portion of the inner surface of the opening
14
which is to be formed thereby. Finally, there is no “wiping” action upon extension and retraction to prevent any solid particles from coming between and interfering with the seal between the tapered surfaces
30
and
32
.
It is therefore an object of the present invention to provide a sealing arrangement between a retractable core and a movable insert which is not position sensitive, which is tolerant of wear between the retractable core and the movable insert, which is relatively simple to refurbish and which is tolerant of the presence of dirt or other solid particles.
SUMMARY OF THE INVENTION
A movable insert for a die-casting mold, the movable insert having a cavity with substantially parallel sides extending thereabout and a core slidably mounted in the cavity. The core is slidably movable between an extended position in which it extends beyond the movable insert and a retracted position in which it does not extend from the movable insert. The core has a connector for releasable attachment to a locator which moves the core between its retracted and its extended positions. A sealing member extends about the core, between the core and the sides of the cavity wall to provide a slidable seal between the core and the sides.
The sealing member may be a resilient metal ring which may be received in a groove extending about the core. The sealing member may be annular and of cast iron or stainless steel.
REFERENCES:
patent: 617396 (1899-01-01), Hay
patent: 1730469 (1929-10-01), Millspaugh
patent: 3433292 (1969-03-01), McDonald
patent: 3442323 (1969-05-01), Lewis
patent: 3849053 (1974-11-01), Bruce et al.
patent: 4611650 (1986-09-01), Fort et al.
patent: 4919189 (1990-04-01), Sato et al.
patent: 5137076 (1992-08-01), Takahashi
patent: 5843494 (1998-12-01), Richardson
patent: 5862853 (1999-01-01), Eliat
patent: 58192652 (1983-11-01), None
Amcan Consolidated Technologies Corp.
Gowling Lafleur Henderson LLP
Kerns Kevin P.
Milne Peter
Stoner Kiley
LandOfFree
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