[0001] The invention relates to a gravity poured foundry mold having a gating system according
to the first portion of claim 1.
Background Art
[0002] In common foundry practice, the flow of metal in a gravity poured mold is controlled
by a gating system so as to produce one or more castings. Once the mold is full, the
gating system, if properly designed, promotes good directional solidification of the
casting or castings produced with that mold. Such molds may be made, for example,
of sand, of graphite, or of a metallic-based material. They also may be based on any
other material or combination thereof, so long as the metal being poured is compatible
with the refractoriness of those materials and with the refractoriness of other materials
used in the mold.
[0003] It has been known to use a skin-strainer in the gating system of a mold. Such skin-strainers
are disclosed generically and in several specific embodiments in U.S. Patent 4,154,289.
[0004] Said US patent discloses a gravity poured foundry mold having a gating system and
at least one complete mold casting cavity, in which said gating system establishing
necessary flow paths between an open outside of the mold and said cavity and comprising
at least one conduit forming one of said flow paths, said conduit being open on opposite
ends thereof and extending directly from an outer surface of said mold to a surface
of said cavity, said conduit comprising means for receiving molten metal and guiding
said molten metal directly toward said cavity such that, during pouring, all molten
metal passing through said conduit flows directly toward said cavity, and said gating
system further comprising straining means interposed between said conduit and said
cavity.
[0005] Figure 1 shows a mold in its pouring position comprising one mold casting cavity
1, and an embodiment of a skin-strainer 2 located somewhere along the top 3 of the
mold casting cavity surface and preferably being located at those points requiring
a traditional riser or feeder. Above the skin-strainer 2 is a conduit 5 which, in
the illustrated embodiment, is a sprue-feeder extending to the top surface 4 of the
mold. The sprue-feeder 5 communicates with mold casting cavity 1 through apertures
6 in skin-strainer 2, the apertures 6 collectively comprising the total passage cross-sectional
area of the skin-strainer.
[0006] Although different molding practices may be used according to which a skin-strainer
2 may be located along the bottom or side surfaces of the mold casting cavity, the
most natural and advantageous location is the surface of the casting cavity 1 which
is on top when the mold is in pouring position. The skin-strainer 2 is firmly held
in position at the lower end of the sprue-feeder 5 using retaining means 7 embedded
in the top of part 8 of the mold. In the particular case of Figure 1, the top of part
8 of the mold is made of bonded sand, the skin-strainer 2 is ceramic and the retaining
means 7 is metallic. Other materials may be used, provided the refractoriness of those
materials is compatible with the temperature of the metal being poured.
[0007] To fill the mold casting cavity 1, melted metal is poured directly into the sprue-feeder
5, first at a rate which is sufficient to quickly fill a major portion of the sprue-feeder,
thereby choking the sprue-feeder, and then at a lower rate which is sufficient to
keep the level of metal in the sprue-feeder substantially constant while the mold
casting cavity 1 is being filled through the apertures 6. As shown, the apertures
6 may advantageously have tapered side walls.
[0008] A mold having a gating system comprising one or more skin-strainers 2 generally allows
for the production of good quality castings at a lower cost than other traditional
gating systems. However, choosing the size of the apertures 6 and the total passage
cross-sectional area of the skin-strainer presents a conflict. On the one hand, the
apertures must be sufficiently small to allow for easy choking of the sprue-feeder
during pouring and to avoid the passing of melt inclusions through the apertures 6
into the mold casting cavity. On the other hand, the passage area must be large enough
to allow not only for good filling of the cavity but also, and when necessary, for
good feeding of the casting during its solidification.
Disclosure of the Invention
[0009] Accordingly, it is an object of the current invention to eliminate the above-noted
conflict in the design of a skin-strainer while retaining the other advantages which
are involved in the use of skin-strainers and by providing additional advantages.
[0010] Consequently, the invention relates to a gravity poured foundry mold as disclosed
in the above mentioned prior art and characterized in that :
- said casting cavity is distinct from said gating system, corresponds to an entire
casting to be produced by said mold and is disposed within and forms part of said
mold ;
- said straining means are provided with aperture means forming a total passage cross-sectional
area of said straining means and extending through said means from said conduit to
said cavity and
restraining means are provided which are distinct from said mold and said straining
means, for at least partially blocking the flow of molten metal through said aperture
means during pouring, said restraining means so comprising means, firstly facilitating
the choking of said conduit during pouring and also assuring the adequate condition
for, secondly filling the cavity and thirdly, and when necessary, for also feeding
the casting formed in said cavity, through said aperture means and after said cavity
has been filled.
[0011] Additional objectives of the current invention are to provide a gating system for
a foundry mold having straining means and providing additional advantages including
the following :
1. To control to any required degree the flow of molten metal entering the mold casting
cavity of any gravity poured foundry mold, making such flow as rapid or slow as required
for good filling of the cavity.
2. To avoid the entry of detrimental melt inclusions into the mold casting cavity.
3. To assure, when necessary, the feeding of the casting in order to obtain the desired
directional solidification of the casting.
4. To provide a gating system having a minimum volume, thereby allowing the pouring
of more molds per melt batch.
5. To reduce gating system pattern work to a very minimum.
6. To minimize the fettling operations that arise from the design of the gating system,
thereby minimizing the amount of post-casting work required and providing a neater
as-cast appearance of the casting.
7. To reduce molding costs by providing a more compact gating system which allows
the use of smaller and cheaper molds and which also allows more molds in the same
molding shop area.
8. To reduce internal stresses and deformations associated with solidification and
cooling of the casting by minimizing the connections between the casting and the gating
system.
9. To permit a very quick filling of the mold casting cavity, thereby allowing pouring
to occur at a lower melt temperature, which saves heating energy, avoids dissolved
gases in the metal, decreases the importance of metal shrinkage, and provides additional
advantages.
[0012] The current application discloses three generic types of restraining means for assisting
the choking of the conduit 5 by restraining the flow of metal through the total cross-sectional
passage area at at least one point between the outside surface of the mold and the
mold casting cavity. Typically, although not always, the restaint is temporary and
promotes the choking of the conduit during pouring. In every case, some structural
means are provided for assuring proper feeding of the casting.
[0013] The restraining means may take the generic forms of a cover, a restraining floating
piece, and a non-floating restraining piece. Each of these generic types of restraining
means may be used by itself or in combination with the others, and more than one restraining
floating piece and non-floating restraining piece may be used in association with
the same skin-strainer.
[0014] The cover comprises at least a main body and a handle, the main body being insertable
into the conduit and having a bottom surface configured to close off, at least partially,
the total flow area available for the passage of molten metal from the conduit 5 into
the cavity 1. The combined effects of the diminished flow area and the volume of the
cover facilitate the choking of the conduit 5. When the conduit 5 is filled sufficiently,
the handle is used to remove the cover from the conduit 5, thereby permitting the
flow of molten metal into the mold casting cavity 1 through an increased flow area.
At such time, the conduit may be kept choked by increasing, as necessary, the flow
rate of metal being poured up to the moment that the mold casting cavity is full.
[0015] Restraining floating pieces also may be used in order to temporarily restrict the
available flow area from the conduit into the cavity. The restraining floating pieces
may be used instead of a cover or, in the alternative, may be used together with a
cover.
[0016] One or more restraining floating pieces are initially disposed in the aperture means
between the conduit and the cavity. In most embodiments, a restraining floating piece
does not completely block the flow area of any given aperture. When the mold casting
cavity is full, the restraining floating piece will float, thereby restoring the original
open area of the aperture in which the piece had been disposed, such that the entire
original area is available for proper feeding of the casting.
[0017] When one or more restraining floating pieces is used simultaneously with a cover,
the restraining floating piece may be disposed in an aperture covered by the cover
or in an aperture not covered by the cover, or a restraining floating piece may be
disposed in both such locations.
[0018] Quite often, in skin-strainer applications, the casting surface (i.e., the surface
of the mold casting cavity) may be modified without detrimental effect on the casting
but favoring the application of a skin-strainer. Similar modifications may be made
when also using the restraining means according to the current invention. Examples
of such modifications are illustrated in Figures 2 and 3.
[0019] Figure 2 shows a skin-strainer 2 located along a modified mold casting cavity surface
9, which defines a volume modification 10 of the mold casting cavity 1. In Figure
2, the volume modification extends upwardly. Figure 3 shows a similar volume modification
which extends sideways.
[0020] At least to some degree, the advantages achieved by using restraining means according
to the current invention may be realized in the absence of a skin-strainer. When a
skin-strainer is used, the use of the restraining means makes the application of a
skin-strainer and its advantages more universal within foundry molding practice.
Brief Description of the Drawings
[0021] A more complete appreciation of the invention and many of the attendant advantages
thereof will be readily obtained as the same becomes better understood by reference
to the following detailed description when considered in connection with the accompanying
drawings, wherein:
FIGURE 1 is a vertical cross-section showing a first embodiment of a skin-strainer
interposed between a mold casting cavity and a sprue-feeder;
FIGURE 2 is a vertical cross-section similar to that of FIGURE 1, the mold casting
cavity being provided with an upwardly-extending volume modification;
FIGURE 3 is a vertical cross-section similar to that of FIGURE 1, the mold casting
cavity being provided with a volume modification that extends sideways;
FIGURE 4 is a broken vertical cross-section showing a first embodiment of a cover
according to the current invention, the cover being a skin-strainer cover cooperating
with a skin-strainer and being disposed in a sprue-feeder, the sprue-feeder being
provided with a sprue-feeder enlargement;
FIGURE 5 is a vertical cross-section illustrating a fragment of FIGURE 4 and showing
a modification of the bottom of the skin-strainer cover to form a second embodiment
of a cover according to the current invention;
FIGURE 6 is a vertical cross-section of a fragment of FIGURE 4 showing a different
modification of the bottom of the skin-strainer cover to form a third embodiment of
a cover according to the current invention;
FIGURE 7 is a vertical cross-section of a fourth embodiment of a cover according to
the current invention;
FIGURE 8A is a vertical cross-section showing a first embodiment of a restraining
floating piece according to the current invention, the piece being disposed in an
aperture of a skin-strainer and being shown elevated slightly above its usual position
during pouring for purposes of illustration;
FIGURE 8B is a horizontal cross-section taken on line VIIIB-VIIIB of FIGURE 8A;
FIGURE 9A is a vertical cross-section of a second embodiment of a restraining floating
piece according to the current invention, the piece being disposed in an aperture
of a skin-strainer and being shown slightly elevated above its normal position during
pouring for purposes of illustration;
FIGURE 9B is a horizontal cross-section taken on line IXB-IXB of FIGURE 9A;
FIGURE 10A is a vertical cross-section showing a third embodiment of a restraining
floating piece according to the current invention, the piece being disposed in an
aperture of a second embodiment of a skin-strainer, the piece being shown slightly
elevated above its normal position during pouring for purposes of illustration;
FIGURE 10B is a horizontal cross-section taken on line XB-XB of FIGURE 10A;
FIGURE 11 is a vertical cross-section showing two restraining floating pieces disposed
in respective apertures of a skin-strainer, one restaining floating piece being covered
by a skin-strainer cover and the other restraining floating piece not being so covered;
FIGURE 12 is a vertical cross-section illustrating a reduction in size of a skin-strainer
cover over that in FIGURE 11 when using restraining floating pieces disposed within
apertures of the skin-strainer that are covered by the skin-strainer cover.
FIGURE 13 is a vertical cross-section illustrating a third embodiment of a skin-strainer,
the skin-strainer having only a single aperture, a fourth embodiment of a restraining
floating piece and a fifth embodiment of a cover, the cover taking the form of a skin-plug,
the piece and the cover being shown slightly elevated above their normal positions
during pouring for purposes of illustration, as is also the case in Figures 14, 15,
19 and 20;
FIGURE 14 is a vertical cross-section illustrating a fourth embodiment of a skin-strainer
and a fifth embodiment of a restaining floating piece;
FIGURE 15 is a vertical cross-section illustrating a sixth embodiment of a cover,
a sixth embodiment of restraining floating piece and further illustrating the use
of a collar of the mold instead of a skin-strainer;
FIGURE 16 is a fragmentary vertical cross-section similar to a portion of FIGURE 15
and illustrating the use of a collar edge insert in addition to a collar;
FIGURE 17 is a vertical cross-section showing a sprue-feeder intersecting a mold casting
cavity at an edge of the cavity such that a portion of the cross-section of the sprue-feeder
communicates with the cavity through an opening and the remainder of the cross-section
of the sprue-feeder is disposed in the mold beyond the cavity, the opening being closed
by a cover according to the current invention;
FIGURE 18 is a vertical cross-section similar to FIGURE 17, wherein the opening is
provided with a collar, a seventh embodiment of a restraining floating piece being
disposed in the opening and covered with a skin-plug;
FIGURE 19 is a vertical cross-section illustrating the use of two skin-strainers,
an eighth embodiment of a restraining floating piece according to the current invention
being disposed in an aperture of one of the skin-strainers and being covered by a
skin-plug;
FIGURE 20 is a vertical cross-section illustrating a ninth embodiment of a restraining
floating piece according to the current invention, the piece being a blind restraining
floating piece;
FIGURE 21 is a vertical cross-section illustrating restraining means in the form of
a foraminous sheet made of a refractory material, the sheet being held between a skin-strainer
and the top part of a mold; and
FIGURE 22 is a vertical cross-section illustrating restraining means in the form of
a foraminous sheet made of a refractory material, the sheet resting on a skin-strainer
and having horizontal dimensions no greater than those of the sprue-feeder.
Best Mode for Carrying Out the Invention
[0022] The following definitions shall apply throughout the disclosure and the claims:
A "metal" is a pure metal or an alloy.
[0023] A "melt" is a batch of molten metal.
[0024] A "casting" is a metal object cast to a desired shape by pouring or injecting, or
both, liquid metal into a mold, as distinct from a metal object shaped by a mechanical
process.
[0025] A "gravity mold" is any foundry mold designed to be filled with molten metal only
under the effect of gravity. Most usually, once the different parts of a gravity mold
are made, the position in which the mold is closed, i.e., the position in which the
different parts of the mold are assembled, is the same position in which the mold
is poured. Nevertheless, and as is well known, a gravity mold may also be closed in
one position and then rotated into a different pouring position.
[0026] An "inclusion" is a particle of impurity, usually non-metallic and not dissolved
in the molten metal. An impurity is generally lighter than the metal and is desirably
separated from the metal before the metal reaches the mold casting cavity.
[0027] A "sprue" is the first conduit, usually vertical in the case of a traditional gravity
mold, through which the metal enters the mold.
[0028] A "riser" or "feeder" is a reservoir connected to the casting so as to provide liquid
metal to the casting during solidifcation, to offset shrinkage which takes place when
the casting solidifies.
[0029] "Fettling", also called "foundry finishing operation" or just "finishing" is the
process of removing the complete gating system and flashes from the casting after
the mold is poured and shaked out, and the carrying out of any necessary operation
such that the casting is dimensioned and shaped in accordance with a casting drawing,
sample, pattern or any agreement with the customer ordering the casting.
[0030] The "mold casting cavity" is the empty part of the mold which corresponds to the
complete casting to be produced within that mold, the casting shape being defined
in accordance with a sample, a casting drawing, a pattern or any other procedure.
Sometimes a modification of the casting surface, and consequently of the casting and
of the corresponding mold casting cavity, may be introduced in the foundry for different
reasons. Such modifications may be such as either are accepted by the casting customer
or eliminated by the foundry at the fettling stage or later at the machine shop. In
any case, if a skin-strainer is located along that modified casting surface, the correspondingly
modified mold casting cavity is the one described in the disclosure and claims herein
by the phrase "mold casting cavity" or just "cavity".
[0031] A "sprue-feeder" is a conduit acting both as a sprue and as a feeder. Previously,
a sprue-feeder has been considered unsuitable for producing a good quality casting.
However, a good quality casting may be made using a sprue-feeder as disclosed herein.
[0032] The term "gating system" includes the traditional complete assembly of sprues, runners,
ingates, vents, flow-offs, feeders and the like necessary to pour and produce a good
casting.
[0033] "Restraining means" is means cooperating with an opening to restrain (i.e., to block
or restrict) flow through an opening, and comprising one or more elements distinct
from the material in which the opening is found. The degree of restraint may be total
or less than total.
[0034] A "skin-strainer" is a straining means which includes a skin-strainer as disclosed
herein and as disclosed generically and in several specific forms in U.S. Patent 4,154,289.
In that U.S. patent, the skin-strainer is identified in the several views by any of
reference numerals 20, 34 and 35.
[0035] "Feeding" is the effect produced by a feeder.
[0036] "Directional solidification" describes the solidification of molten metal in a mold
casting cavity such that feeding metal is always available for that portion of the
casting that is just solidifying.
[0037] "Refractoriness" is the ability of a material to withstand high temperatures as,
for example, contact with molten metal. In the foundry art, the refractoriness of
a material is a relative term and depends upon the metal being melted and poured to
produce castings, as different foundry metals melt at temperatures over a widely varying
range.
[0038] When a metal having a low melting point is being poured, a wide variety of materials
exhibit refractoriness, including other metals having higher melting points. As the
melting point of the metal being poured increases, the range of materials exhibiting
refractoriness is reduced and may ultimately include only some metals properly protected
with an adequate refractory wash or one of those materials usually referred to as
"refractory materials" or just ceramics, including all solid industrial materials
that are neither metallic nor organic, which are highly heat resistant and have low
thermal conductivity, whether in a granulated or powdered form. Refractory materials
may be given many different shapes by using a bond that may be mechanical, physical,
chemical, sintered, a combination of the above, or any other type of bond.
[0039] When an accessory or part is required to be mechanically strong and have a high heat
resistance, it is known in the art to associate the use of refractory material with
metal in combined form or the use of a cermet, which involves the technique of bonding
a ceramic with a metal.
[0040] Referring now to the drawings, wherein like reference numerals designate identical
or corresponding parts throughout the several views, and more particularly to Figure
4 thereof, there is shown a part of a skin-strainer 2 disposed between sprue-feeder
5 and mold casting cavity 1, the skin-strainer 2 having therein a plurality of apertures,
the horizontal cross-sections of which collectively comprise the total cross-section
passage area of the skin-strainer 2. The sprue-feeder 5 passes upwardly through the
top of part 8 of a mold to the top surface 4 of the mold.
[0041] Also shown in Figure 4 is a skin-strainer cover including a body 11, the bottom surface
of the body 11 being in contact with the top surface of skin-strainer 2 so as to block
a fraction of the total cross-sectional passage area formed by the apertures of the
skin-strainer. Apertures 12 are covered by the skin-strainer cover, while additional
apertures 6 are not covered by the skin-strainer cover.
[0042] In the embodiment shown in Figure 4, the skin-strainer cover body 11 may advantageously
be made of a refractory material. A handling means is partially embedded in the body
11 and comprises an anchoring form 13, a connecting bar 14 and a handle 15. The handling
means can be made by forging, welding or any other suitable and known procedure.
[0043] If desired, an enlargement 16 may be formed in sprue-feeder 5 to provide an additional
volume than would otherwise be provided by the lesser diameter of the lower portion
of the sprue-feeder. Also, such an enlargement 16 makes it easier to choke sprue-feeder
5.
[0044] When the mold is ready to be cast and with the skin-strainer cover held in position
as shown, as by handle 15, molten metal is poured either into the enlargement 16,
or directly into sprue-feeder 5, quickly enough to choke the sprue-feeder. The first
metal begins to pass through apertures 6 into cavity 1. When a proper level of molten
metal is achieved in sprue-feeder 5, or in enlargement 16 if present, the skin-strainer
cover is lifted and removed from the sprue-feeder. Similtaneously, pouring is increased
in order to keep the sprue-feeder 5 choked. The pouring continues until the molten
metal starts rising, thereby indicating that the mold casting cavity is full. Pouring
is then stopped. Of course, if when pouring is completed the level of the metal in
sprue-feeder 5 finishes too low and becomes insufficient for a proper feeding of the
casting, the necessary difference of metal is added.
[0045] While the mold is being poured, venting of the cavity 1 cannot be accomplished properly
through the choked sprue-feeder 5. Therefore, any known venting method should be used
such that the gases in the mold casting cavity 1 are pushed outside while the molten
metal is rising in the cavity.
[0046] Figure 5 shows a second embodiment of a skin-strainer cover which provides improved
mating between skin-strainer cover body 11 and skin-strainer 2. The bottom surface
of the skin-strainer cover body 11 is provided with a plurality of plug-like penetrations
17 which fit within those apertures 12 of the skin-strainer which are blocked by the
skin-strainer cover. The shape of the apertures of the skin-strainer 2 may be modified
to promote the mating of the surfaces, for example, by modifying the taper of the
apertures 12 or defining any other suitable shape for the apertures 12.
[0047] Figure 6 illustrates a third embodiment in which the upper surface of the skin-strainer
2 does not contact the bottom surface of the skin-strainer body 11. This embodiment
illustrates the fact that, with well-fitting penetrations 17, it no longer is necessary
to have such contact between the upper surface of the skin-strainer 2 and the lower
surface of the body 11. In this embodiment, the downward force applied on the skin-strainer
cover 11 and against the skin-strainer 2 must balance the upward force on the skin-strainer
cover resulting from the molten metal until the moment that the skin-strainer cover
is lifted.
[0048] Figure 7 illustrates a fourth embodiment of a skin-strainer cover according to the
invention in which the skin-strainer cover is formed of standardized parts. The body
of the skin-strainer cover comprises at least a bottom standard part 18 and, if required
by the length of the sprue-feeder 5, also by one or more auxiliary cover extension
parts 19. A longitudinal passage 20 is formed in the bottom standard part 18 and communicates
with a recess 21 formed at the bottom of the bottom standard part 18.
[0049] Anchoring form 13 of a standardized connecting bar 22 is disposed in recess 21. The
standard connecting bar 22 passes through the passage 20 and through corresponding
passages 23 of any auxiliary cover standard extension parts 19 that may be present.
A standardized handle 24 is connected to the standardized connecting bar 22 as, for
example, by using a threaded fastener. The threaded fastener may be formed by a thread
at the upper end of the standardized connecting bar 22, a washer 25 and a nut 26,
this threaded fastener additionally permitting the tightening of the entire skin-strainer
cover as a whole.
[0050] The anchoring form 13 may be square or hexagonal in cross-section, and recess 21
may desirably be large enough to permit the introduction into recess 21 of a tube
wrench for facilitating the tightening of the skin-strainer cover as a hole. Following
the assembly of the skin-strainer cover, and if recess 21 is larger than necessary
for accommodating the anchoring form 13, the recess 21 may be filled with a refractory
mix 27 so as to avoid contact between the molten metal and the anchoring form 13 during
the stage when the skin-strainer cover is lifted upwardly within the sprue-feeder
5.
[0051] The bottom standard part 18 and auxiliary extension standard parts 19 may be made
of any suitable refractory material, applying any known manufacturing procedure for
making parts with such materials. The metallic standard parts also may be made by
known procedures.
[0052] Advantageously, the skin-strainer cover may be held in place against the skin-strainer
2 during pouring by hand and lifted at the right moment during pouring. However, for
big castings it may be easier or even necessary to provide other means for lifting
to assure both proper initial holding in place during pouring and the subsequent lifting
operation.
[0053] The skin-strainer cover is in contact with the molten metal for a comparatively short
time, usually a matter of seconds. Accordingly, if the body of the skin-strainer cover
is made of a material with a sufficiently high degree of refractoriness, the cover
typically will be reusable for the pouring of several or even many molds.
[0054] In the embodiments of Figures 4-7, the total passage cross-sectional area of the
skin-strainer should be at least the minimum necessary both for adequate filling of
the cavity 1 during pouring and also for adequate feeding of the casting following
pouring. However, there will now be described additional embodiments according to
the current invention in which one or more restraining floating pieces, or one or
more non-floating restraining pieces, or both, are employed as restraining means.
Such restraining means partially block the apertures in which they are disposed, thereby
creating a restricted cross-sectional passage area presented by the assembly of the
skin-strainer and the restraining pieces disposed therein. Accordingly, the total
passage cross-sectional area of the skin-strainer 2 itself, considered alone, will
be greater than the minimum necessary for adequate filling of the cavity 1.
[0055] Figures 8A and 8B respectively show vertical and horizontal cross-sections of restraining
floating piece 28 according to the current invention. The restraining floating piece
28 is disposed in aperture 6 of skin-strainer 2 and has a lower surface 30, an upper
surface 31 and an external lateral surface 32. Passage 29, formed in the restraining
floating piece, communicates sprue-feeder 5 with mold casting cavity 1. Because of
the presence of passage 29, the restraining floating piece only partially blocks the
aperture 6 of skin-strainer 2.
[0056] For purposes of illustration, the restraining floating piece is shown slightly elevated
above its actual position during pouring, at which time lateral surface 32 contacts
the lateral wall of aperture 6. When the restraining floating piece of Figures 8A
and 8B is in its position for pouring, surface 30 will be lower than lower surface
33 of skin-strainer 2, and surface 31 of the restraining floating piece will be higher
than upper surface 34 of skin-strainer 2.
[0057] Recesses 35 are formed around the lower portion of the restraining floating piece
and are interrupted by tooth-like projections 37, hereinafter called teeth. The radially-outer
surfaces of the teeth 37 are coincident with the lateral surface 32 of the restraining
floating piece and therefore also contact the wall of the aperture 6. Preferably,
three such teeth 37 are provided.
[0058] The upper surfaces 36 of the recesses 35 are disposed at a level above that of lower
surface 33 of skin-strainer 2 and lower than that of upper surface 34 of skin-strainer
2 when the restraining floating piece is in its pouring position.
[0059] Although other shapes may be used, in the illustrated embodiment the aperture 6 is
shown as circular, the restraining floating piece 28 is generally annular, and the
bottom surface 33 of skin-strainer 2 is flat.
[0060] During the pouring of metal into the sprue-feeder 5, the restraining floating piece
serves to restrict the area of apertures 6, reducing the now available cross-sectional
area to that created by passage 29. When mold casting cavity 1 is full, the restraining
floating piece 28 floats, thereby increasing the effective cross-sectional area that
is now available for feeding of the casting.
[0061] The ability of restraining floating piece 28 to float depends upon a number of factors
including the weight of the restraining floating piece, the buoyant force acting on
the restraining floating piece that results from the weight of the molten metal displaced
thereby under the Pascal principle, and the fact that a portion of surface 32 is in
contact with wall 6 and therefore is not initially available for being urged upwardly
by molten metal in the cavity 1 after the cavity 1 is filled.
[0062] In order to ensure that the balance of forces acting on restraining floating piece
28 results in a net upward buoyant force, a number of factors in addition to the weight
of the piece may be considered. In particular, to increase buoyancy, the level of
surface 36 may be made as near as possible to that of surface 34, the number of teeth
37 may be made as few as possible, the slope of the wall of aperture 6 may be as nearly
vertical as possible, the level of surface 30 may be as low as necessary or as permitted
by the mold casting cavity 1, and the level of surface 31 may be as high as necessary.
Naturally, the weight of the restraining floating piece will be a function of its
composition.
[0063] Figures 9A and 9B respectively show vertical and horizontal cross-sections of a second
embodiment of a restraining floating piece according to the current invention. Instead
of a passage 29, the restraining floating piece is configured such that a number of
passages 38 are formed when the piece is inserted into the aperture 6, the passages
extending along the entire height of the external surface 32 of the restraining floating
piece, the passages communicating the sprue-feeder 5 and the cavity 1. Again, the
restraining floating piece is shown slightly elevated above its pouring position for
purposes of illustration. Bottom surface 30 of the restraining floating piece is disposed
at a level below that of bottom surface 33 of skin-strainer 2. Upper surface 31 of
the restraining floating piece is shown disposed at a level above that of top surface
34 of skin-strainer 2, but it may be desirable for surface 31 and surface 34 to be
coincident, depending upon any desired degree of blockage that may be provided by
a cover, if a cover is used to cover that particular restraining floating piece.
[0064] Figures 10A and 10B respectively show vertical and horizontal cross-sections of a
third embodiment of a restraining floating piece according to the current invention.
Also shown is a second embodiment of a skin-strainer. The restricted passage cross-sectional
area of the aperture 6 is provided by grooves 39 formed in the sidewall of the skin-strainer
aperture, passing entirely through the thickness of the skin-strainer. Accordingly,
no passages need be incorporated into the construction of the restraining floating
piece itself.
[0065] Again, the restraining floating piece is shown for purposes of illustration elevated
somewhat above its position for pouring. In the pouring position, the bottom surface
30 of the restraining floating piece is at a level below the bottom surface 33 of
skin-strainer 2, and surface 31 is disposed at a level lower than that of surface
34.
[0066] Additional embodiments may be created by combining teachings from various ones of
the illustrated embodiments.
[0067] Figure 11 illustrates the use of two restraining floating pieces in combination with
a skin-strainer cover. However, any number of restraining floating pieces may be used,
and more than one embodiment may be used at the same time. In addition, the restraining
floating pieces may be used without the assistance of a skin-strainer cover.
[0068] For purposes of illustration, there is shown a restraining floating piece 40 disposed
in an aperture 12 which is covered by the skin-strainer cover body 11 and a restraining
floating piece 28 disposed in an aperture 6 of skin-strainer 2 which is not covered
by skin-strainer cover body 11. Pieces 28 and 40 are shown as modifications of the
embodiment of Figures 8A and 8B. Piece 28 is modified by raising its lower surface
30 above the bottom surface 33 of the skin-strainer, whereas the piece 40 is modified
such that its upper surface 31 is below the level of top surface 34 of skin-strainer
2. It should be noted that passage 29 of piece 28 will be available for communicating
sprue-feeder 5 with cavity 1 immediately upon the initiation of pouring, whereas passage
29 of piece 40 will not be available for such communication until the skin-strainer
cover is lifted.
[0069] The upper surface 31 of the one or more restraining floating pieces disposed in the
apertures 12 covered by the skin-strainer may also be disposed at the level of top
surface 34 of the skin-strainer or even above the level of surface 34 of the skin-strainer
so long as the bottom of the skin-strainer cover body 11 is effective to cover the
holes 29. For example, when the bottom of the skin-strainer cover body 11 is flat,
as shown, the upper surfaces 31 of the restraining floating pieces disposed in the
apertures 12 may lie in a common plane with the bottom of the cover body 11.
[0070] Figure 12 illustrates an alternative in which the available volume in sprue-feeder
5 is increased by decreasing the size of skin-strainer cover body 11 without decreasing
the number of apertures that are covered by the body 11. In particular, restraining
floating pieces 40 are disposed with their upper surfaces 31 even with surface 34,
and the size of the body 11 is just sufficient to block the passages 29. As in Figure
11, there is shown a modification of the restraining floating pieces in which the
bottom surfaces 30 thereof are disposed at a level above that of bottom surface 33
of skin-strainer 2.
[0071] Figure 13 shows a fifth embodiment of a cover body 11, in the form of a skin-plug,
a third embodiment of a skin-strainer 2, and a fourth embodiment of a restraining
floating piece.
[0072] The skin-strainer 2 has a single aperture 12 which receives restraining floating
piece 40. As in a previous embodiment, recesses 35 are interrupted by teeth 37, but
upper surfaces 36 of the recesses are inclined for somewhat increasing the volume
of the restraining floating piece and its floatability. As before, the restraining
floating piece is illustrated somewhat elevated above its position for pouring. In
the pouring position, lateral surface 32 contacts the wall of aperture 12. Provided
at an upper portion of restraining floating piece 40 is a laterally-extending expansion
41 having a lower surface 42 disposed at a level above the upper surface 34 of skin-strainer
2. Surface 41 enhances the floatability of restraining floating piece 40 by providing
an additional surface on which may act the metalstatic pressure of molten metal in
sprue-feeder 5.
[0073] Restraining floating piece 40 is provided with a passage 29, a portion of which is
spherical and has a radius R as shown. The remainder of the passage 29 may advantageously
be conic, as shown at 44.
[0074] The skin-strainer cover comprises a skin-strainer cover body 11, bottom 45 of which
is spherical and has a radius r which is as close as practical to the radius R in
order to obtain good mating of surfaces 43 and 45. Advantageously, the center of curvature
C of the radii R and r may be disposed at a level above that of upper surface 31 of
the restraining floating piece. An advantage of the elevated center of curvature is
that the spherical matching surfaces may accommodate some tilt of the skin-strainer
cover body without adversely affecting the quality of contact between the surfaces
43 and 45 and, therefore, without adversely affecting the degree to which passage
29 is blocked.
[0075] Also shown in Figure 13, and further complementing the mold, is an optional sprue-feeder
extender 46 for increasing the height of the sprue-feeder above the top surface 4
of the mold, when desired. In addition, and further complementing the mold, Figure
13 further shows an optional sprue-feeder expander 47 for increasing the volume of
available molten metal in the sprue-feeder, when desired. Variation are possible.
For example, sprue-feeder extender 46 and sprue-feeder expander 47 may be made integrally
as one piece, or sprue-feeder expander 47 may be placed directly on the top surface
4 of the mold when the sprue-feeder extender 46 is not desired. Known foundry practice
may be used to ensure that the various contacting surfaces of the mold, extender 46
and expander 47 are properly sealed in order to avoid leakage of molten metal.
[0076] Modifications of the restraining floating piece 40 also are possible. For example,
surface 42 may be lowered and made to rest on surface 34 whenever needed to avoid
a wedge effect between the surface of aperture 12 of the skin-strainer 2 and the lateral
surface 32 of the restraining floating piece 40. This modification may be accomplished
without loosing the floatability of the restraining floating piece 40 by making appropriate
adjustments of its dimensions.
[0077] In the embodiment of Figure 13, the skin-strainer cover body 11 completely blocks
the passage 29. Accordingly, no molten metal passes into the mold casting cavity 1
before the skin-strainer cover is lifted. This embodiment makes it quite easy for
pourers of lower skill to accomplish choking of sprue-feeder 5. It also provides a
container of sufficient size that it may be filled, even before lifting of the skin-strainer
cover, with a volume of metal that is sufficient to fill the mold casting cavity 1,
the other parts of the gating system such as ventings or traditional feeders, and
the sprue-feeder 5 itself with the necessary amount of metal for filling the cavity
and feeding the corresponding casting. A mark may be placed before pouring on the
sprue-feeder expander 47 for indicating a level corresponding to that volume.
[0078] After the pouring is accomplished, the skin-strainer cover removed and the cavity
1 filled, the metalstatic pressure of the molten metal acts on surfaces 30, a portion
of surface 32, and on the walls of recesses 35 to produce a net upward balance of
forces, thereby causing the restraining float piece 40 to float. The piece 40, when
it floats, also automatically protects, to some degree, the upper surface of the molten
metal in the sprue-feeder 5. In addition, as with the previous embodiments using restraining
floating pieces, the exit of the restraining floating piece 40 from the aperture 12
restores the original total passage cross-sectional area of the skin-strainer for
proper feeding of the mold casting cavity 1 from the sprue-feeder 5.
[0079] In the embodiment of Figure 13, because the sprue-feeder 5 including the expander
16 contains the total amount of metal needed, the cavity 1 can be filled without additional
human intervention, an important advantage in assuring proper operation.
[0080] As noted above, this embodiment of a skin-strainer cover body 11 may be just called
a skin-plug, inasmuch as it comprises a plug placed near the level of the skin of
the casting.
[0081] As with the previous embodiments of the restraining floating means, the embodiment
of Figure 13 may be used without the skin-strainer cover, provided that the passage
29 and sprue-feeder 5 are such that the sprue-feeder may be choked easily. In such
a case, the spherical surface 43 of the restraining floating piece is not necessary
and may be replaced if desired by an extension of the conic surface 44. Also in such
a case, sprue-feeder expander 47 typically will be eliminated. The sprue-feeder extender
46 may be kept up if necessary for proper feeding of the mold casting cavity 1.
[0082] Figure 14 shows a fourth embodiment of a skin-strainer and a fifth embodiment of
a restraining floating piece. The embodiment is similar to that of Figure 13, except
that the lateral wall of restraining floating piece 40 comprises a spherical segment
48 and a conic section 49, and the wall of aperture 12 of the skin-strainer is correspondingly
formed with a spherical segment 50 and a conic segment 51.
[0083] It should be noted that the various embodiments disclosed herein may be made of standardized
parts which are usable in various combinations, thereby increasing the versatility
of the system. Thus, the cover of the embodiments of Figures 13 and 14 may be made
of standardized parts and constructed similarly to the cover illustrated in Figure
7, such that the skin-strainer cover body 11 becomes a skin-strainer cover standard
bottom part 18. For simplicity of illustration, there is not shown in the drawing
elements corresponding to recess 21 and elements 20, 13, 22 and 27 as shown in Figure
7. Figure 14 has been further simplified by not showing any necessary skin-strainer
retaining means 7 as shown in Figures 1-3.
[0084] The embodiment of Figure 14 provides even further versatility with standardized parts,
arising from the spherical nature of the matings both between skin-plug 18 and restraining
floating piece 40, and between restraining floating piece 40 and skin-strainer 2.
Not only may restraining floating piece 40 be used alone or in combination with a
skin-plug as shown in Figure 14, but the skin-strainer 2 may be used in combination
with the skin-plug 18 without the interposition of a restraining floating piece 40.
In such a case, a larger skin-plug 18 will be used having a greater radius of curvature
r, such that the surface 45 will mate properly with spherical surface 50 on skin-strainer
2.
[0085] Figure 15 shows a sixth embodiment of a cover, a sixth embodiment of a restraining
floating piece, a further overall embodiment according to the current invention which
is made possible when the top of part 8 of the mold is made of a material such as
a sand mold aggregate. A skin-strainer is not present, but a strainer means is provided
in the form of sprue-feeder collar 52 defining a sprue-feeder restricted passage 53,
the sprue-feeder collar 52 being formed as part of the top part 8.
[0086] Because of the materials used, the aperture formed by restricted passage 53 will
be larger than an aperture available in a skin strainer. Accordingly, the restraining
floating piece must be correspondingly larger, but is still provided with a lateral
surface having a spherical segment 48 and a conic segment 49.
[0087] The sprue-feeder collar 52 is substantially thicker than skin-strainer 2 and is provided
with a spherical surface 54 and a conic surface 55. The lateral dimension of the sprue-feeder
5 also is larger. It terminates in a sloping surface 56 which is connected to a lateral
wall of the sprue-feeder 5 at a radius 57 for avoiding a sharp corner.
[0088] Collar 52 is formed of a material much less resistant to the forces it will encounter
than prefabricated skin-strainer 2 which, depending upon its size and on the metal
poured, is typically made of ceramic, metal or a combination of the two. Accordingly,
in the embodiment of Figure 15, the collar 52 must be made sufficiently resistant
and therefore is thicker than a skin-strainer and is provided with slope 56 and radius
57. However, the thicker sprue-feeder collar 52 is less advantageous for proper feeding
of the casting once the mold is poured and the metal still liquid. To compensate,
the aperture 53 is typically larger than that found in an embodiment such as Figure
14. The size of the sprue-feeder 5 also is increased in order that the metal in aperture
53 solidifies later than that part of the casting which must be fed by sprue-feeder
5. It should be noted that the provision of a larger aperture 53 and larger sprue-feeder
5 imply that more molten metal must be used and more fettling work must be done.
[0089] In the embodiment of Figure 15, the strength of collar 52 may be increased, although
not easily, by using an adequate metallic reinforcing armature which can be made following
known practices in the foundry molding art.
[0090] As in the embodiment of Figure 14, the restraining floating piece may be used without
the skin-plug, or a larger skin plug may be used without a restraining floating piece.
[0091] Also shown in Figure 15 is the presence of one or more optional channels 45′ on the
bottom 45 of the skin-plug. This embodiment may also be used in Figure 14. When the
surface 45 comes into contact with surface 43, or surface 50 (FIGURE 14), or surface
54, the channel or channels 45′ allow for some molten metal to pass form the sprue-feeder
5 into the cavity 1 from the start of pouring but before the cover is lifted. The
channel or channels 45′ are not so large as to hinder adequate choking of the sprue-feeder.
[0092] Additional variations of the channels 45′ are possible. For example, instead of being
formed in surface 45 of the skin-plug, they may be formed in surfaces 43, 50 or 54
in Figures 14 and 15.
[0093] The restraining floating piece should be made of any material having an adequate
refractoriness and a lower density than the molten metal being poured, so that the
restrainng floating piece can withstand the impact of the molten metal, erosion, temperature,
the weight of the skin-strainer cover if used, and the like, and also such that the
piece may float once the mold casting cavity is full. Typically, a restraining floating
piece will be made of a sintered refractory material.
[0094] The sprue-feeder extender 46 and sprue-feeder expander 47 may be made of any material
whose refractoriness and resistance are compatible with such applications. Typically,
sprue-feeder extender 46 will be made of bonded molding sand, and may advantageously
be used in combination with exothermic materials for that part of the extender which
will remain in contact with the metal after the mold is poured. Sprue-feeder exapnder
47 is preferably made of sintered refractory material. Because the amount of time
it will remain in contact with the molten metal will typically be very short, the
expander may be reused many times.
[0095] It may be seen from the above that a characteristic of a restraining floating piece
is that it floats free of an aperture in which it is disposed once its restraining
function is over, thereby enlarging the effective area available for feeding the casting.
There will now be described an additional embodiment of a-restraining piece which
does not float but remains disposed in an aperture, yet nevertheless enhances feeding.
Such a piece will be called a non-floating restraining piece. If the piece 28 illustrated
in Figures 8A and 8B were made, for example, of a material sufficiently dense that
it will not float, the piece will become a non-floating restraining piece. As will
be described later, additional modification may be made to the embodiment shown in
Figures 8A and 8B to further assist in the prevention of floating.
[0096] With the non-floating restraining piece remaining in place once the mold casting
cavity 1 is full, recesses 35 will fill with molten metal and form a hot reservoir
or heat source around passage 29. The reservoir 35 is thermally-adjacent the passage
29, by which it is meant that the composition and structure of the non-floating restraining
piece is such that the hot metal in reservoir 35 is effective to keep the metal hot
in passage 29. Thus, the heat source in recess 35 achieves the desired effect that
molten metal in passage 29 remains liquid for a longer period of time and, consequently,
the ability of passage 29 to feed the casting is enhanced. With this enhancing, passage
29 tends to be equivalent to a substantially larger passage and closer to the aperture
6. Nevertheless, the passage 29 still retains its other advantages of facilitating
choking of the sprue-feeder during pouring and further provides for easier fettling
(for example, the type of metal and casting shape may allow for a sprue-feeder that
can be knocked off more easily).
[0097] Additional modificatins that may be made to the structures shown in Figures 8A and
8B to diminish the capacity for floating or otherwise improving the operation of the
non-floating restraining piece include enlarging the recesses 35 inwardly toward passage
29 (which also increases the heat source), dimensioning the overall height of the
piece 28 such that the passage 29 is shortened, adjusting the slopes of the wall of
aperture 6 and of surface 32, eliminating the teeth 37 (which also increases the heat
source), and providing a fresh refractory wash on surface 32 and on the wall of skin-strainer
aperture 6 between the surface 32 and the wall of aperture 6 in order to cause surface
32 and the wall to stick together.
[0098] It may be seen that the various embodiments according to the current invention may
be standardized, thereby greatly enhancing the ease of use, accuracy and confidence
with which they may be used. With standardization, there may be made available to
foundries variously sized, prefabricated, interchangeable and correlated skin-strainers,
restraining floating pieces, non-floating restraining pieces and covers, thereby making
available corresponding elements that adequately match with each other. The prefabrication
and standardization also may be extended to any auxiliary means or element necessary
or useful for making easier the application of those restraining means already described,
or any other.
[0099] Such standardization, for example, could mean establishing: first, a unique pattern
or perhaps several patterns of matching shapes between the restraining elements, which
patterns could be similar to those disclosed herein or any other; second, a unique
pattern or perhaps several patterns of open area shapes for the skin-strainers and
the restraining pieces; third, elements permitting adequate variation of pouring rates,
i.e., of open areas; and fourth, suitable sets of different sizes of, for example,
skin-strainers, restraining pieces and covers. Most such patterns will be adequate
for pouring any kind of metal, but some could be specialized for example for pouring
steels and irons, some others for pouring aluminum alloys in particular or non-ferrous
alloys in general.
[0100] The standardization also could include a consideration of using several different
materials in manufacturing the various elements.
[0101] As stated above, other related elements also could be standardized and prefabricated
such as sprue-feeder extenders, sprue-feeder expanders, skin-strainer cover extensions
and the like.
[0102] With standardization, to every size of skin-strainer there could be one or even a
group of corresponding restraining floating pieces that match with it and also one
or even a group of skin-strainer covers doing the same. Similarly, one or even several
covers can be associated with every restraining piece.
[0103] All of the skin-strainer covers considered in the standardization could be configured
such that any skin-strainer cover of the set may be used with a corresponding skin-strainer
or with a corresponding interposed restraining piece.
[0104] Of course, from all the numerous possible combination and variations among the elements,
the tendency will be to prefer just a few and only those that are more versatile for
standard prefabrication.
[0105] It should be pointed out that standardization permits one to establish definite preferences
of some embodiments over others. For example, the embodiment shown in Figure 14 is
preferable to the one shown in Figure 15, because the comparative thinness of a standard
well-prefabricated skin-strainer 2, when compared to sprue-feeder collar 52, provides
for better feeding, a smaller neck connection (i.e., a smaller aperture), a smaller
sprue-feeder size and better matching of restraining means.
[0106] Nevertheless, standardization can still provide for the improvement of the less-preferred
embodiment of Figure 15, as shown in Figure 16. Shown in Figure 16 is a collar edge
58 which is standardized, prefabricated and typically made of ceramic. Collar edge
58 has an aperture 53, the sidewall of which comprises spherical segment 54 and conic
segment 55 which generally follow and correspond to the same surfaces of collar 52
as shown in Figure 15. Also as shown, the collar edge 58 contains upper and lower
surfaces that match with surfaces 3 and 56, forming extensions of those surfaces.
Collar edge 58 has an outside back surface 59 adequate to firmly connect and support
the collar edge 58 to the remaining part of the collar 52. When making the top of
part 8 of the mold, the collar edge 58, for example, may be placed around the pattern
for the passage 53 and underneath the pattern for the sprue-feeder 5. Molding sand
will then be rammed against the casting pattern, against the collar edge 58 and against
the pattern for the sprue-feeder 5.
[0107] In use, because the collar edge 58 presents surfaces 54 and 55 that are harder and
smoother than the corresponding surfaces illustrated in Figure 15, it will assure
a more accurate matching with any restraining means as, for example, a skin-plug,
a restraining floating piece, a non-floating restraining piece, and the like.
[0108] The gating system described in this specification is advantageously compatible with
the performance of in-mold metallurgical treatments.
[0109] Such treatments, as also in the case of ladle treatments, involve the use of one
or several metallurgical treatment products which must be in contact with the molten
metal shortly before the molten metal reaches the mold casting cavity. It is known
in the art to place such products somewhere in the filling section of a traditional
gating system, usually formed by the assembly of sprues, channels and ingates, in
such a way that the molten metal is automatically treated as it flows toward the mold
casting cavity.
[0110] Considering by way of example the embodiment of Figure 13, such a metallurgical treatment
product or products may easily be placed on surfaces 34 or 31, or in sprue-feeder
enlargement 16 on the top surface of sprue-feeder extension 46 or in a lateral chamber
specially formed off of sprue-feeder 5 during the molding stage, either in the top
part 8 of the mold or in sprue-feeder extender 46, or in several or all of such locations,
or in any other location.
[0111] As stated above, in the type of embodiment shown in Figure 13 it is possible to pour
into sprue-feeder 5 and sprue-feeder enlargement 16 the full amount of molten metal
necessary for pouring the mold, and this amount of metal may be added before the cover
is lifted. Therefore, in such embodiments it is possible to adjust the timing of the
lifting of the skin-plug to the completion of such metallurgical treatment, an important
advantage in terms of efficiency and economy. In fact, by lifting the skin-strainer
cover just in time, it is possible to avoid fading of the treatment effect as can
occur in the case of ladle treatments and it is further possible to avoid insufficient
treatment of molten metal as can be the case in known versions of in-mold treatment.
[0112] Referring now to Figure 17, there is shown an embodiment in which sprue-feeder 5
overlaps the mold casting cavity contour surface such that the sprue-feeder intersects
the cavity 1 at an edge of the cavity and a portion of the cross-section of the sprue-feeder
5 communicates with the cavity 1 through an opening 53, the remainder of the cross-section
of the sprue-feeder 5 being disposed in the mold beyond the cavity. Numeral 60 is
that part of the sprue-feeder lateral wall which is in front of the cavity, and 61
is the rest of that lateral wall. There is thereby formed a partial bottom of the
conduit which extends from the opening to sidewall 61 of the conduit. The level of
the partial bottom immediately adjacent the opening is no lower than the level of
the top 3 of the cavity surface.
[0113] The level of bottom 64, at least where that bottom is adjacent to the opening 53,
is elevated above the level of the top 3 of the mold casting cavity by a distance
63, which nevertheless can be made as small as desired. Therefore, the distance 63
corresponds to the vertical dimension of an aperture 53 (or an aperture 12 in the
preceding embodiments), communicating sprue-feeder 5 and mold casting cavity 1 through
a single aperture. In such a case, a collar with a height equivalent to distance 63
is naturally formed. A skin-strainer also may be used having a thickness corresponding
to the distance 63 for further reducing contact of the sprue-feeder with the cavity.
[0114] In the case of Figure 17, a restraining means such as a cover 11, as shown, or a
restraining floating piece or any other restraining means may be used by resting the
restraining means at least partly on surfaces 64 and 60 and, if desired, allowing
a portion of it to protrude into mold casting cavity 1 (not shown).
[0115] The embodiment of Figure 17 allows for good feeding once the mold is full, because
the distance 63 can be made quite short or even reduced to zero, although good feeding
is somewhat impaired by the fact that the communication between the cavity 1 and the
sprue-feeder 5 is not at the center of the sprue-feeder. Accordingly, the improvement
of Figure 18 may be used according to which a depression 65 is formed in the bottom
of the sprue-feeder 5, thereby creating a wall 66, and by additionally creating a
portion of a collar 52, or both. The wall 66 and collar 52 become hotter in the case
of Figure 18 than in the case of similar mold parts of Figure 17 due to the presence
of molten metal in depression 65 and over collar 52, thereby improving the feeding
action.
[0116] Referring now to Figure 19, there is shown one example of a generic case in which
a sprue-feeder terminates at a skin-strainer 2 having one or plural apertures (or,
in the alternative, at a collar 52, or still without any straining means at all and
in which straining means 2′ are disposed at one or even several additional locations
along the length of the sprue-feeder. One such possible additional upstream location
is the top surface 4 of the mold, as shown in Figure 19. Surface 4 may be considered
in this regard as analogous to the mold casting cavity surface to which the skin-strainer
or collar concepts also can be applied, and consequently, the concept of restraining
means.
[0117] In Figure 19, the sprue-feeder is separated into two parts 5′ and 5˝ by a second
strainer 2′ located at surface 4, sprue-feeder part 5′ being located adjacent cavity
1 and sprue-feeder part 5˝ being disposed above strainer 2′. The strainer 2′ is shown
in combination with a further embodiment of a restraining floating piece 40 and a
cover 11. For clarity of illustration, restraining floating piece 40 is shown elevated
slightly above the position at which it will reside during pouring. This embodiment
of restraining floating piece 40 has some variations of shape when compared with that
of Figure 13. Before pouring, surface 42 will rest on surface 34 for supporting the
restraining floating piece 40. However, surface 32 angles inwardly so as not to be
in full contact with the lateral surface of the aperture 12, thereby avoiding the
possibility of a wedge effect between restraining floating piece 40 and strainer 2′,
which wedge effect could diminish the floatability of the restraining floating piece.
The lateral extension 41 of the restraining floating piece 40 exhibits an optional
alternative upward and inward taper toward the top of the restraining floating piece.
[0118] Variations of these embodiments also are possible. For example, a collar 52 may be
used instead of strainer 2′, or at the same location of strainer 2′ there may also
be used a combination of straining means with a cover without the interposition of
any restraining floating piece.
[0119] If skin-strainer 2 is used and in order for proper operation, the open area of skin-strainer
2 should be less than the open area of restraining floating piece 40 such that, once
cover 11 is lifted during pouring, the sprue-feeder lower part 5′ will be choked,
and so creating an advantage in terms of increased casting soundness of a second straining
effect while filling of cavity 1 is taking place. In the alternative, and when convenient,
the open area of skin-strainer 2 may be reduced by using some restraining means, for
example, a restraining floating piece, which could consequently allow for a smaller
effective open area of the restraining floating piece associated with strainer 2′.
[0120] If the skin-strainer 2 of Figure 19 comprises more than one aperture, the open area
may also be reduced by using at least one blind restraining floating piece.
[0121] In a further modification, the section 5˝ may have a somewhat greater cross-sectional
area than the section 5′, and strainer 2′ may just stand on surface 4 of top part
8 of the mold, presenting a contour size within the limit of such increased cross-section.
In such a case and by the end of the mold filling, not only will the restraining floating
piece associated with strainer 2′ float, but the strainer 2′ could float as well if
its floatability is defined in terms similar to those used for floating pieces already
defined.
[0122] Still referring to Figure 19, and still considering the case in which the cross-sectional
area of 5˝ is somewhat greater than the section of 5′, it is possible to use a restraining
floating piece 40 but without any strainer interposed between the restraining floating
piece and surface 4 as, in such a case, a restraining floating piece of greater lateral
dimension can have surface 42 standing directly on the sprue-feeder edge of surface
4.
[0123] Going further, in the day-to-day foundry shop practice, and as already mentioned,
it may be justified in some cases to avoid the straining effect at the mold casting
cavity surface, by terminating the sprue-feeder 5 full-open at cavity 1. In such a
case, the straining effect could be disposed at least at one upstream level such as
level 4 in Figure 19. Such a practice would have the effect, among others, of losing
the efficiency of the feeding capacity because sprue-feeder part 5′ would not be choked
and consequently would not be as hot as it is in normal skin-strainer practice, a
loss of efficiency which can somewhat be compensated for by increasing the cross-sections
of the portions 5′ and 5˝. Accordingly, a restraining means may be associated with
straining means within a sprue-feeder conduit at a location independent of the mold
casting cavity surface.
[0124] Today, non-metallic casting materials such as polymers have been and are being developed,
and their study is being included in programs of metallurgical engineering. Foundry
technology can be applied to those materials, and foundry vocabulary can be used by
extension or analogy when referring to them. In particular, the invention herein disclosed
also can be applied to such non-metallic casting materials, either to control only
the cavity filling or to control both the cavity filling and the corresponding casting
feeding, whether or not the material exhibits solidification shrinkage.
[0125] Figure 20 shows an additional embodiment of a restraining floating piece according
to the current invention. Restraining floating piece 67 is a blind restraining floating
piece, so-called because neither the piece nor the aperture 6 in which the piece is
disposed provides a passage communicating sprue-feeder 5 with cavity 1 while the piece
remains disposed in the aperture. This embodiment is generally useful and possible
with skin-strainers having more than one aperture, to still allow for filling. No
molten metal passes from sprue-feeder 5 to cavity 1 through the corresponding aperture
until the piece 67 floats upon the filling of cavity 1 through at least one additional
aperture. The embodiment shown in Figure 20 is like that shown in Figures 8A and 8B,
except that there is no passage 29. However, the embodiment of Figure 20 is representative
only, and a blind restraining floating piece may be created, for example, by modifying
any other embodiment of a restraining floating piece to remove the various forms of
passages from sprue-feeder 5 to cavity 1.
[0126] Considering that to date porous ceramic is available and that, when in contact with
molten metal, such porous ceramic allows for the molten metal to go through the porous
material, which material can be called metal-permeable material, it is possible to
take advantage of this property for designing and manufacturing restraining means
according to the current invention. Such restraining means will restrain the flow
of metal toward the cavity but will not block it completely. For example, if a blind
restraining floating piece like or similar to the one shown in Figure 20 is made of
a porous ceramic material, it will not be blind any more. It will, instead, allow
molten metal to pass toward the cavity and still, if conveniently shaped, it will
float once the cavity is full. Such a piece can be used in combination with straining
means presenting only one aperture. In the cases when the molten metal filling the
porous ceramic piece and the cavity being already filled, the molten metal within
the porous ceramic piece furthermore staying molten long enough to feed the casting,
of course at this stage the floatability of the piece is not mandatory anymore.
[0127] Yet another type of restraining means according to the current invention is a foraminous
sheet made of a refractory material. Such a sheet may be made of a metallic mesh,
fiberglass mesh, carbon fiber mesh, standard open materials such as perforated metal
plate, expanded metal or the like, and all refractory materials which are bought off
the shelf in sheets, rolls and the like. It is intended to include all thin flexible
sheets that are permeable to molten metal and made of a refractory material, it being
understood that refractoriness is a relative term as previously defined. Such sheets
68 can be used as shown in Figures 21 and 22.
[0128] In Figure 21, sheet 68 is placed on upper surface 34 of skin-strainer 2 in order
that the combination of skin-strainer and its associated retaining means (the retaining
means not being shown for the sake of simplicity) support the sheet 68. The sheet
68 covers the skin-strainer and extends beyond the sides of conduit 5, remaining partly
pressed against the material of mold 8. Skin-strainer 2 is shown with one aperture
6, but it may be provided with a plurality of apertures. Aperture 6 is shown with
a reversed taper when compared with the taper of aperture 6 in, for example, Figure
1, assuming that the mold casting cavity surface 3 is conventionally modified following
the skin-strainer 2 central profile.
[0129] Obviously, sheet 68 restrains the open area of skin-strainer 2, thereby easing the
choking of sprue-feeder 5, allowing filling of the cavity because of the metal permeability
of the sheet 68, and feeding, when necessary, the corresponding casting because the
thinness of the sheet 68 allows for the material of the sheet 68 to rapidly reach
the temperature of the molten metal. Accordingly, the material of the sheet 68 does
not promote early solidification and therefore does not block feeding toward the casting
cavity. Such additional restraining means may naturally be called a restraining sheet
68.
[0130] Figure 22 is identical to Figure 21 with the exception that the restraining sheet
68 rests freely on surface 34 of skin-strainer 2 and within the limit of the contour
of conduit 5.
[0131] Depending on, for example, the size of hole 6, the flexibility of restraining sheet
68, and the like, either the situation of Figure 21 or of Figure 22 will be preferred,
in order that sheet 68 substantially remains in its position throughout the pouring
operation. As the flexbility of sheet 68 tends to increase, or as the size of aperture
6 tends to increase, or both, the situation of Figure 21 will tend to be preferred
over that of Figure 22.
[0132] In the case of Figure 22, if sheet 68 is lighter than molten metal, it will float
at the most once cavity 1 is filled. If restraining sheet 68, in the case of Figure
22 does not float either because it is heavy enough or because the situation corresponds
to that of Figure 21, restraining sheet 68 will remain in the same position and once
the metal is soldified, the sheet 68 will weaken contact of the casting and sprue-feeder
and so will ease the possibility of separating the sprue-feeder 5 by knocking if off.
[0133] As the restraining sheet 68 can be more or less flexible, it can be advantageous
in some cases to consider the simultaneous use of more than one layer, for example
two superposed layers, placing a less flexible sheet directly on the skin-trainer
and another more flexible sheet having better restraining quality on the top of it.
[0134] As can be envisaged, the possibility of using restraining sheets presents a diversity
of options.
[0135] It has so been clearly established that restraining means reinforcing the effect
of straining means such as skin-strainers, collars or the like, can be embodied by
using materials permeable to molten metal, wether they are porous ceramics, thin flexible
foraminous sheets of refractory materials, or the like.
[0136] The gating system as disclosed in U.S. patent 4 154 289 which basically defines straining
means at the casting surface skin level and the gating system as disclosed in the
present specification which basically defines further means called restraining means,
primarily look, firstly, for pouring clean metal into the mold casting cavity through
an easier choking of the conduit 5 and, secondly, for a complete and good filling
of the mold casting cavity ; complementarily and when required by casting soundness
they also, thirdly, look for assuring the adequate feeding of said casting.
[0137] Generally, a feeding requirement will be present together with choking and filling
though, sometimes, it might not be mandatory. For example, and as is well known in
foundry practice, it could be so because the thinness of the casting promotes a rapid
solidification, because the feeding is assured from another part of the casting through
a traditional riser, because the feeding requirement is eliminated by the presence
of chilling procedures, and the like.
[0138] Nevertheless, it is still good to keep in mind that in foundry practice it is a common
fact that the gating points (points where metal enters the cavity) of any gating system
tend to create "hot points" in the corresponding casting which, not infrequently,
need to be specially feeded.
[0139] The fulfillment of any of those three requirements along the mold pouring and solification
times depends on the resulting open areas of the gating system at the choking, filling
or feeding stages. Depending on the characteristics of the casting (weight, size,
shape, metal, etc.) the three requirements can be fulfilled by the same open area
(this is the case as shown for example in Figures 1, 2 and 3, which are embodiments
of the above-cited U.S. Patent and is also the case when a restraining non-floating
piece is used without any cover, when the case of Figure 21 is present, etc.) or by
two different open areas as is the case for example of Figures 4-10 and also Figure
17, or still by three different open areas as is the case for example of Figures 11-15
and also Figure 18. An embodiment of the type shown in Figure 19 even provides the
possibility of using more than three successive open areas.
[0140] The case of Figure 20, which and as already explained in this specification is used
with a strainer having at least two apertures, corresponds to a system presenting
two different open areas: one for choking and filling and the other for feeding. It
could also correspond to a system presenting three different open areas by associating
a cover to the strainer open area not blocked by blind restraining floating means:
one area for choking (which eventually can be zero), a bigger one for filling and
the biggest for feeding.
[0141] In general foundry practice, it is frequent that the open area required for feeding
is greater or even in some cases much greater than the area that is required for filling
and, in turn, that the open area required for filling is greater or even much greater
than the area required for choking. The present gating system being very compact,
on one side, nevertheless still allows quite easily and efficiently, by the other,
to adapt to any required diversity of consecutive open areas.
[0142] It is possible in some cases, for example when the casting presents thin and extended
walls, that filling requires a greater or even a much greater open area than is necessary
for feeding, if feeding is required. In such a case, plainly, the system will be reduced
to a system having two open areas: one for choking (which most generally will be zero)
and the other for filling, as the feeding requirement, if present, obviously will
be automatically covered.
[0143] It will be easily realized by what has been shown and explained in the present specification
and the drawings that other different systems may be defined presenting combinations
of two and three (or even more) consecutive open areas.
[0144] Obviously, numerous modifications and variations of the present invention are possible
in light of the above teachings. It is therefore to be understood that within the
scope of the appended claims, the invention may be practiced otherwise than as specifically
described herein.
1. A gravity poured foundry mold having a gating system and at least one complete mold
casting cavity, in which :
- said gating system establishing necessary flow paths between an open outside of
the mold and said cavity (1) and comprising at least one conduit (5) forming one of
said flow paths, said conduit being open on opposite ends thereof and extending directly
from an outer surface of said mold to a surface of said cavity, said conduit comprising
means for receiving molten metal and guiding said molten metal directly toward said
cavity such that, during pouring, all molten metal passing through said conduit flows
directly toward said cavity, and
- said gating system further comprising straining means interposed between said conduit
and said cavity,
characterized in that :
- said casting cavity is distinct from said gating system, corresponds to an entire
casting to be produced by said mold and is disposed within and forms part of said
mold ;
- said straining means (2) are provided with aperture means (12) forming a total passage
cross-sectional area of said straining means and extending through said means from
said conduit to said cavity and
restraining means (11; 18; 19; 28; 40; 67; 68) are provided which are distinct
from said mold and said straining means, for at least partially blocking the flow
of molten metal through said aperture means during pouring, said restraining means
so comprising means, firstly facilitating the choking of said conduit (5) during pouring
and also assuring the adequate condition for, secondly filling the cavity and thirdly,
and when necessary, for also feeding the casting formed in said cavity, through said
aperture means and after said cavity has been filled.
2. Apparatus according to Claim 1, characterized in that said conduit comprises a sprue-feeder
(5), said mold comprises a sprue-feeder extender (46-47), said conduit passing through
said sprue-feeder extender and having therein substantially the same cross-sectional
area as the cross-sectional area of said conduit (5) at said skin-strainer (2).
3. Apparatus according to Claim 2, characterized in that said mold further comprises
a sprue-feeder expander, said conduit (5) passing through said sprue-feeder expander
and having therein a substantially greater cross-sectional area that the cross-sectional
area of said conduit at said skin-strainer (2).
4. Apparatus according to Claim 1, characterized in that said conduit comprises a sprue-feeder
(5), said mold further comprises a sprue-feeder expander (46), said conduit passing
through said sprue-feeder expander and having therein a substantially greater cross-sectional
area than the cross-sectional area of said conduit at said skin-strainer.
5. Apparatus as claimed in Claim 1, characterized in that said restraining means comprises
at least one restraining floating piece (28) of a composition and shape such that
it will float when said cavity (1) is full, said restraining floating piece being
disposed in an aperture (6) of said skin-strainer and partially but not fully blocking
said aperture, thereby forming a restricted cross-sectional passage area (29) presented
by the assembly of said restraining floating piece and said skin-strainer (2), said
restraining floating piece being so supported that it is free to float when said cavity
is full, thereby increasing the effective cross-sectional area that is available for
feeding the casting through the aperture in which said restraining floating piece
had been disposed, said restraining floating piece being able to withstand the effects
of temperature, impact, pressure and erosion resulting from the pouring of molten
metal.
6. Apparatus according to Claim 5, characterized in that said restraining means further
comprises cover means (11) disposed in said conduit for temporarily and further-blocking
at least a portion of said restricted cross-sectional passage area (29) presented
by the assembly of said skin-strainer (2) and said restraining floating piece (28).
7. Apparatus according to Claim 6, characterized in that said cover means (11) are disposed
in contact with said skin-strainer (2) and block a plurality of apertures thereof
(12).
8. Apparatus according to Claim 6, characterized in that said cover means (11) are disposed
in contact with said restraining floating piece (28).
9. Apparatus according to Claim 8, characterized in that said restraining floating piece
has a passage (29) formed therein communicating said conduit (5) and said cavity (1)
and forming at least a portion of said restricted cross-sectional passage area of
said assembly of said skin-strainer and said restraining floating piece, said cover
means (11) comprising means for at least partially blocking said passage in said restraining
floating piece.
10. Apparatus according to Claim 9, characterized in that said aperture means of said
skin-strainer (2) comprise a single aperture, said cover means being received in said
passage of said restraining floating piece.
11. Apparatus according to Claim 10, characterized in that said cover means (11) is received
in said passage of said restraining floating piece such taht at least one channel
is formed therebetween communicating said conduit and said cavity.
12. Apparatus according to Claim 1, characterized in that said restraining means comprise
at least one non-floating piece (28) having a composition and shape such that it will
not float when said cavity is full, said non-floating piece being disposed in an aperture
of said skin-strainer and partially but not fully blocking said aperture, thereby
forming a restricted cross-sectional passage area presented by the assembly of said
non-floating piece and said skin-strainer, said non-floating piece comprising a recess
(35) so disposed that it will fill with molten metal, said recess comprising means
for establishing a heat source of hot metal thermally adjacent the metal in said restricted
cross-sectional passage area (29) of said assembly for increasing the feeding capacity
of said restricted cross-sectional passage area.
13. Apparatus according to Claim 12, characterized in that restraining means further comprise
cover means (11) disposed in said conduit for temporarily and further blocking at
least a portion of said restricted cross-sectional passage area presented by the assembly
of said skin-strainer and said non-floating piece.
14. Apparatus according to Claim 13, characterized in that said cover means are disposed
in contact with said skin-strainer (2) and block plurality of apertures (12) thereof.
15. Apparatus according to Claim 13, characterized in that said cover means are disposed
in contact with said non-floating piece.
16. Apparatus according to Claim 15, characterized in that said non-floating piece has
a passage formed therein communicating said conduit (5) and said cavity (1) and forming
at least portion of said restricted cross-sectional passage area of said assembly,
said cover means (11) comprising means for at least partially blocking said passage
in said non-floating piece.
17. Apparatus according to Claim 16, characterized in that said aperture means of said
skin-strainer (2) comprise a single aperture, said cover means being received in said
passage of said non-floating piece.
18. Apparatus according to Claim 17, characterized in that said cover means is received
in said passage of said non-floating piece such that at least one channel is formed
therebetween communicating said conduit and said cavity.
19. Apparatus according to Clain 1, characterized in that said restraining means comprise
a cover means (11) disposed in contact with said skin-strainer (2) for temporarily
blocking at least a portion of said total passage cross-sectional area of said skin-strainer.
20. Apparatus according to Claim 19, characterized in that said cover means (11) comprise
at least one positioning surface cooperating with a lateral wall (32) of said aperture
means (12) of said skin-strainer to keep said cover means in place during filling.
21. Apparatus according to Claim 20, characterized in that said cover means further comprise
:
- a standard and prefabricated body (18) made of refractory material, said at least
one positioning surface being formed thereon, there being a recess on an underside
of said body and a hole extending along the length of said body and communicating
with said recess ;
- a standard as prefabricated auxiliary metallic bar (22) having a head at one end
thereof and a fillet at the other end thereof, said bar being disposed in said hole
such that said head is disposed in said recess ;
- standard and prefabricated tightening means (13) affixing said bar to said body,
wherein said bar comprises lifting means ; and
- a refractory auxiliary mix (27) filling the remaining space in said recess, covering
when necessary said head of said bar and matching the external contour of said body.
22. Apparatus according to Claim 21, characterized in that said cover means further comprise
at least one standard and prefabricated auxiliary cover extension (19), made of a
refractory material and having an extension hole extending along the length thereof,
said metallic bar extending through said extension hole.
23. Apparatus according to Claim 20, characterized in that said aperture means of said
skin-strainer comprise a single aperture (12), said positioning surface of said cover
means being disposed therein.
24. Apparatus according to Claim 23, characterized in that said positioning surface 15
mating with a wall of said aperture such that at least one channel is formed therebetween
communicating said conduit and said cavity.
25. Apparatus according to any of Claims 5, 12 or 19, characterized in that said restraining
means comprise at least one blind floating piece (67) of a composition and shape such
that it will float when said cavity is full and means supporting said blind floating
piece such that it will not move substantially upon initial pouring of molten metal
into said conduit but is free to float when said cavity is full, thereby permitting
feeding of the casting through the aperture that had been closed by said blind floating
piece, said blind floating piece being able to withstand the effects of temperature,
impact, pressure and erosion resulting from the pouring of molten metal.
26. Apparatus according to Claim 1, characterized in that it comprises a metallurgical
treatment product disposed in said conduit (5), said product comprising means for
treating molten metal in said conduit.
27. A gravity poured foundry mold according to claims 1-26 characterized in that said
gating system comprises a collar (52) integrally formed of the material of said mold
and interposed between said conduit and said cavity such that a surface of said collar
is a surface of said cavity, there being an aperture communicating said conduit and
said cavity at the location of said collar.
28. Apparatus according to Claim 27, characterized in that it comprises a collar edge
insert distinct from said mold and said restraining means, said collar (52) supporting
said collar edge insert, said aperture passing through said collar edge insert.
29. Apparatus according to Claim 27, characterized in that conduit comprises a sprue-feeder,
said mold comprising a sprue-feeder extender, said conduit passing through said sprue-feeder
extender (46) and having therein substantially the same cross-sectional area as the
cross-sectional area of said conduit at said collar.
30. Apparatus according to Claim 29, characterized in that said mold further comprises
a sprue-feeder expander (47), said conduit passing through said sprue-feeder expander
and having therein a substantially greater cross-sectional area that the cross-sectional
area of said conduit at said collar.
31. Apparatus according to Claim 27, characterized in that said conduit comprises a sprue-feeder,
said mold further comprises a sprue-feeder expander and having therein a substantially
greater cross-sectional area than the cross-sectional area of said conduit at said
collar.
32. Apparatus according to Claim 27, characterized in that it comprises a metallurgical
treatment product disposed in said conduit, said product comprising means for treating
molten metal in said conduit.
33. A gravity poured foundry mold according to claim 1-32 characterized in that one of
said straining means is interposed along the length of said conduit.
34. Apparatus according to any one of Claims 1 or 27, characterized in that said restraining
means comprise a foraminous sheet (68) made of a refractory material.
35. Apparatus according to any one of Claims 1 or 27, characterized in that said restraining
means comprise a foraminous refractory material.
36. Apparatus according to any one of Claims 1 or 27, characterized in that said restraining
means are made of a material able to withstand the effects of temperature, impact,
pressure and erosion resulting from the pouring of molten metal.
37. Apparatus according to any one of Claims 1 or 27, characterized in that said restraining
means comprise standarized prefabricated elements.
1. Moule de fonderie à coulée par gravité ayant un système d'alimentation et au moins
une cavité pour la coulée entière du moule, dans lequel :
- ledit système d'alimentation établissant nécessairement les chemins d'écoulement
entre une ouverture vers l'extérieur du moule et ladite cavité 1 et comprenant au
moins un conduit (5) formant un desdits chemins d'écoulement, ledit conduit étant
ouvert à ses extrémités opposées et s'étendant directement d'une surface extérieure
dudit moule à une surface de ladite cavité, ledit conduit comprenant des moyens pour
recevoir le métal fondu et guider ledit métal fondu directement vers ladite cavité
de telle sorte que, pendant la coulée, tout le métal passant par ledit conduit s'écoule
directement vers ladite cavité, et
- ledit système d'alimentation comprenant, en outre, des moyens de filtre interposés
entre ledit conduit et ladite cavité,
caractérisé en ce que :
- ladite cavité de coulée est distincte dudit système d'alimentation, correspond à
une coulée intégrale qui doit être produite par ledit moule et est disposée à l'intérieur
et forme une partie dudit moule ;
- lesdits moyens de filtre (2) sont prévus avec des systèmes d'ouverture (12) formant
une surface transversale totale de passage desdits moyens de filtre et s'étendant
à travers lesdits moyens à partir dudit conduit vers ladite cavité et
des moyens de retenue (11,18,19,28,40,67,68) sont prévus qui sont distincts dudit
moule et desdits moyens de filtre, pour bloquer, au moins partiellement, l'écoulement
du métal fondu à travers lesdits systèmes d'ouverture pendant la coulée, lesdits moyens
de retenue comprenant ainsi des moyens,, facilitant en premier lieu l'engorgement
dudit conduit (5) pendant la coulée et assurant également la condition adéquate pour,
en second lieu, remplir la cavité et troisièmement, et si nécessaire, pour alimenter
également la coulée formée dans ladite cavité, à travers lesdits systèmes d'ouverture
et après que ladite cavité a été remplie.
2. Dispositif selon la revendication 1, caractérisé en ce que ledit conduit comprend
une descente de coulée (5), ledit moule comprend un dispositif d'allongement de descente
de coulée (46, 47), ledit conduit passant à travers ledit dispositif d'allongement
de descente de coulée et ayant à l'intérieur sensiblement la même surface transversale
que celle dudit conduit (5) au niveau dudit filtre de peau (2).
3. Dispositif selon la revendication 2, caractérisé en ce que ledit moule comprend de
plus un dispositif d'élargissement de descente de coulée, ledit conduit (5) passant
à travers ledit dispositif d'élargissement de descente de coulée et ayant à l'intérieur
une surface transversale sensiblement plus grande que la section transversale dudit
conduit au niveau du filtre de peau (2).
4. Dispositif selon la revendication 1, caractérisé en ce que ledit conduit comprend
une descente de coulée (5), ledit moule comprend en outre un dispositif d'élargissement
de descente de coulée (46), ledit conduit passant à travers ledit dispositif d'élargissement
de descente de coulée et ayant à l'intérieur une surface transversale plus grande
que la section transversale dudit conduit au niveau dudit filtre de peau.
5. Dispositif selon la revendication 1, caractérisé en ce que lesdits moyens de retenue
comprennent au moins une pièce flottante de retenue (28) de composition et de forme
telle qu'elle flottera quand ladite cavité (1) est pleine, ladite pièce flottante
de retenue étant disposée dans une ouverture (6) dudit filtre de peau et obturant
partiellement mais pas complètement ladite ouverture, formant de ce fait une surface
de passage transversale réduite (29) présentée par l'assemblage de ladite pièce flottante
de retenue et dudit filtre de peau (2), ladite pièce flottante de retenue étant supportée
de sorte qu'elle est libre de flotter quand ladite cavité est pleine, augmentant de
ce fait la surface transversale effective qui est disponible pour alimenter la coulée
à travers l'ouverture dans laquelle ladite pièce flottante de retenue a été disposée,
ladite pièce flottante de retenue étant capable de résister aux effets de température,
de choc, de pression et d'érosion résultant de la coulée du métal fondu.
6. Dispositif selon la revendication 5, caractérisé en ce que lesdits moyens de retenue
comprennent de plus des moyens de couvercle (11) disposés dans ledit conduit pour
obturer temporairement et davantage au moins une partie de ladite surface transversale
réduite de passage (29) présentée par l'assemblage dudit filtre de peau (2) et de
ladite pièce flottante de retenue (28).
7. Dispositif selon la revendication 6, caractérisé en ce que les moyens de couvercle
(11) sont disposés en contact avec ledit filtre de peau (2) et obturent une pluralité
de ses ouvertures (12).
8. Dispositif selon la revendication 6, caractérisé en ce que lesdits moyens de couvercle
(11) sont disposés en contact avec ladite pièce flottante de retenue (28).
9. Dispositif selon la revendication 8, caractérisé en ce que ladite pièce flottante
de retenue possède un passage (29) formé à l'intérieur faisant communiquer ledit conduit
(5) et ladite cavité (1) et formant au moins une partie de ladite surface transversale
réduite de passage dudit assemblage du filtre de peau et de ladite pièce flottante
de retenue, lesdits moyens de couvercle (11) comprenant des moyens pour fermer au
moins partiellement ledit passage dans ladite pièce flottante de retenue.
10. Dispositif selon la revendication 9, caractérisé en ce que lesdits systèmes d'ouverture
du filtre de peau (2) comprennent une seule ouverture, lesdits moyens de couvercle
étant reçus dans ledit passage de ladite pièce flottante de retenue.
11. Dispositif selon la revendication 10 caractérisé en ce que lesdits moyens de couvercle
(11) sont reçus dans dans ledit passage de ladite pièce flottante de retenue de telle
sorte que au moins un canal soit formé entre eux faisant communiquer ledit conduit
et ladite cavité.
12. Dispositif selon la revendication 1, caractérisé en ce que lesdits moyens de retenue
comprennent au moins une pièce non flottante (28) possédant une composition et une
forme telle qu'elle ne flottera pas quand la cavité est pleine, ladite pièce non flottante
étant disposée dans une ouverture dudit filtre de peau et obturant partiellement mais
non complètement ladite ouverture, formant de ce fait une surface transversale réduite
de passage présentée par l'assemblage de ladite pièce non flottante et dudit filtre
de peau, ladite pièce non flottante comprenant un évidement (35) disposé de sorte
qu'il se remplira de métal fondu, ledit évidement comprenant des moyens pour établir
une source de chaleur de métal chaud adjacente thermiquement au métal de ladite surface
transversale réduite de passage (29) dudit assemblage pour augmenter la capacité d'alimentation
de ladite surface transversale réduite de passage.
13. Dispositif selon la revendication 12, caractérisé en ce que les moyens de retenue
comprennent de plus des moyens de couvercle (11) disposés dans ledit conduit pour
obturer temporairement et davantage au moins une partie de ladite section transversale
réduite de passage présentée par l'assemblage dudit filtre de peau et de ladite pièce
non-flottante.
14. Dispositif selon la revendication 13, caractérisé en ce que lesdits moyens de couvercle
sont disposés en contact avec ledit filtre de peau (2) et obturent une pluralité de
ses ouvertures (12).
15. Dispositif selon la revendication 13, caractérisé en ce que lesdits moyens de couvercle
sont disposés en contact avec ladite pièce non flottante.
16. Dispositif selon la revendication 15, caractérisé en ce que ladite pièce non flottante
possède un passage forme à l'intérieur faisant communiquer ledit conduit (5) et ladite
cavité (1) et formant au moins une partie de ladite surface transversale réduite de
passage dudit assemblage, lesdits moyens de couvercle (11) comprenant des moyens pour
obturer au moins partiellement ledit passage dans ladite pièce non flottante.
17. Dispositif selon la revendication 16, caractérisé en ce que lesdits systèmes d'ouverture
du filtre de peau (2) comprennent une seule ouverture, lesdits moyens de couvercle
étant reçus dans ledit passage de ladite pièce non flottante.
18. Dispositif selon la revendication 17, caractérisé en ce que lesdits moyens de couvercle
sont reçus dans ledit passage de ladite pièce non flottante de telle sorte qu'au moins
un canal soit formé entre eux faisant communiquer ledit conduit et ladite cavité.
19. Dispositif selon la revendication 1, caractérisé en ce que lesdits moyens de retenue
comprennent lesdits moyens de couvercle (11) disposés en contact avec ledit filtre
de peau (2) pour obturer temporairement au moins une partie de ladite surface transversale
totale de passage dudit filtre de peau.
20. Dispositif selon la revendication 19, caractérisé en ce que lesdits moyens de couvercle
(11) comprennent au moins une surface de repère coopérant avec une paroi latérale
(32) desdits systèmes d'ouverture (12) dudit filtre de peau pour garder lesdits moyens
de couvercle en place pendant le remplissage.
21. Dispositif selon la revendication 20, caractérisé en ce que lesdits moyens de couvercle
comprennent de plus :
- un corps standard et préfabriqué (18) réalisé en matériau réfractaire, au moins
une dite surface de repère étant formée dessus, il existe un évidement sur le côté
de dessous dudit corps et un trou s'étendant selon la longueur dudit corps et faisant
communiquer avec ledit évidement ;
- une barra métallique auxiliaire standard comme préfabriquée (22) comportant une
tête à une de ses extrémités et un raccord à son autre extrémité, ladite barre étant
disposée dans ledit trou de telle sorte que ladite tête est disposée dans ledit évidement
;
- des moyens de serrage standard et préfabriqués (13) fixant ladite barre audit corps,
dans lesquels ladite barre comprend des moyens de levage ; et
- un mélange auxilaire réfractaire (27) remplissant l'espace restant dans ledit évidement
recouvrant si nécessaire ladite tête de ladite barre et ajusté au contour externe
dudit corps.
22. Dispositif selon la revendication 21, caractérisé en ce que lesdits moyens de couvercle
comprennent en outre, au moins une extension de couvercle auxiliaire standard et préfabriquée
(19) réalisée en un matériau réfractaire et comportant un trou s'étendant le long
de sa longueur, ladite barre métallique s'étendant à travers ledit trou de l'extension.
23. Dispositif selon la revendication 20, caractérisé en ce que lesdits systèmes d'ouverture
de filtre de peau comprennent une seule ouverture (12), ladite surface de repère desdits
moyens de couvercle y étant disposée à l'intérieur.
24. Dispositif selon la revendication 23, caractérisé en ce que la surface repère (15)
s'adaptant à une paroi de ladite ouverture de telle sorte qu'au moins un canal soit
formé entre elles faisant communiquer ledit conduit et ladite cavité.
25. Dispositif selon les revendications 5, 12 ou 19, caractérisé en ce que lesdits moyens
de retenue comprennent au moins une pièce flottante aveugle (67) de composition et
de forme telle qu'elle flottera quand ladite cavité est pleine et des moyens supportant
ladite pièce flottante aveugle de telle sorte qu'elle ne se déplacera pas sensiblement
lors de la coulée initiale de métal fondu dans ledit conduit mais est libre de flotter
quand ladite cavité est pleine, permettant de ce fait l'alimentation de la coulée
à travers l'ouverture qui a été obturée par ladite pièce flottante aveugle, ladite
pièce flottante aveugle étant capable de résister aux effets de température, de choc,
de pression et d'érosion résultant de la coulée de métal fondu.
26. Dispositif selon la revendication 1, caractérisé en ce qu'il comprend un produit de
traitement métallurgique disposé dans ledit conduit (5), ledit produit comprenant
des moyens pour traiter le métal fondu dans ledit conduit.
27. Moule de fonderie à coulée par gravité selon les revendications 1-26, caractérisé
en ce que ledit système d'alimentation comprend un collier (52) formé intégralement
du matériau dudit moule et interposé entre ledit conduit et ladite cavité, une ouverture
existant pour faire communiquer ledit conduit et ladite cavité à la position dudit
collier.
28. Dispositif selon la revendication 27, caractérisé en ce qu'il comprend une pièce d'insertion
en bordure de collier distincte dudit moule et desdits moyens de retenue, ledit collier
(52) supportant la pièce d'insertion en bordure de collier, ladite ouverture passant
à travers ladite pièce d'insertion en bordure de collier.
29. Dispositif selon la revendication 27, caractérisé en ce que le conduit comprend une
descente de coulée, ledit moule comprenant un dispositif d'extension de descente de
coulée, ledit conduit passant à travers ledit dispositif d'extension de descente de
coulée (46) et y possédant à l'intérieur sensiblement la même surface transversale
que la surface transversale dudit conduit au niveau du collier.
30. Dispositif selon la revendication 29, caractérisé en ce que ledit moule comprend de
plus un dispositif d'élargissement de descente de coulée (47), ledit conduit passant
à travers ledit dispositif d'élargissement de descente de coulée et y comportant à
l'intérieur une surface transversale sensiblement plus grande que la surface transversale
dudit conduit au niveau dudit collier.
31. Dispositif selon la revendication 27, caractérisé en ce que ledit conduit comprend
une descente de coulée, ledit moule comprend en outre un dispositif d'élargissement
de descente de coulée et y comportant à l'intérieur une surface transversale sensiblement
plus grande que la surface transversale dudit conduit au niveau dudit collier.
32. Dispositif selon la revendication 27, caractérisé en ce qu'il comprend un produit
de traitement métallurgique disposé dans ledit conduit, ledit produit comrenant des
moyens pour traiter le métal fondu dans ledit conduit.
33. Moule de fonderie à coulée par gravité selon les revendications 1-32, caractérisé
en ce qu'un des moyens de retenue est interposé le long de la longueur dudit conduit.
34. Dispositif selon l'une quelconque des revendications 1 ou 27, caractérisé en ce que
lesdits moyens de retenue comprennent une plaque mince foraminée (68) réalisée en
matériau réfractaire.
35. Dispositif selon l'une quelconque des revendications 1 ou 27, caractérisé en ce que
lesdits moyens de retenue comprennent un matériau réfractaire foraminé.
36. Dispositif selon l'une quelconque des revendications 1 ou 27, caractérisé en ce que
lesdits moyens de retenue sont réalisés en un matériau capable de résister aux effets
de température, de choc, de pression et d'érosion résultant de la coulée du métal
fondu.
37. Dispositif selon l'une quelconque des revendications 1 ou 27, caractérisé en ce que
lesdits moyens de retenue comprennent des éléments standardisés préfabriqués.
1. Schwerkraft-Gießform mit einem Eingußsystem und wenigstens eine vollständigen Gießformhohlraum,
wobei:
- das Eingußssystem die erforderlichen Strömungswege zwischen einer offenen Außenseite
der Gießform und dem Hohlraum (1) bereitstellt und wenigstens eine Leitung (5) aufweist,
die einen der Strömungswege bildet, wobei die Leitung an gegenüberliegenden Seiten
offen ist und sich direkt von einer Außenfläche der Gießform zu einer Fläche des Hohlraums
erstreckt, wobei die Leitung Vorrichtungen aufweisen, um geschmolzenes Metall aufzunehmen
und es direkt zum Formhohlraum zu leiten, derart, daß während des Gießens das gesamte
geschmolzene Metall, daß durch die Leitung fließt, direkt auf den Hohlraum zufließt,
und
- das Eingußsystem weiterhin eine Filtriereinrichtung aufweist, die zwischen der Leitung
und dem Hohlraum angeordnet ist,
dadurch gekennzeichnet, daß
- der Gießhohlraum von dem Eingußsysstem abgesetzt ist, einem ganzen, durch die Gießform
zu erzeugenden Gußstück enstpricht und innerhalb der Gießform angeordnet und Teil
dieser Form ist;
- die Filtriereinrichtung (2) eine Öffnungseinrcihtung (12) aufweist, die die Querschnittsfläche
des gesamten Durchlasses der Filtriereinrichtung bildet und sich durch diese hindurch
von der Leitung zum Hohlraum erstreckt, und
- eine Schließeinrichtung (11; 18, 19; 28; 40; 67; 68) vorgesehen ist, die von der
Gießform und der Filtriereinrichtung abgesetzt ist, um wenigstens teilweise den Fluß
des geschmolzenen Metalls durch die Öffnungseinrichtung beim Gießen zu blockieren,
wobei die Schließeinrichtung zudem eine Einrichtung aufweist, die erstens das Vollhalten
der Leitung (5) während des Gießens erleichtert, und um außerdem die passenden Bedingungen
zu schaffen, um zweitens den Hohlraum zu füllen und drittens gegebenenfalls auch das
in dem Hohlraum geformte Formstück durch die Öffnungen und nach dem Füllen des Hohlraums
nachzufüllen.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Leitung einen Eingußspeiser (5) aufweist, wobei die Gießform eine Speiserverlängerung
(46- 48) hat und die Leitung durch die Verlängerung hindurchführt und darin im wesentlichen
dieselbe Querschnittsfläche wie die der Leitung (5) am Skin-Filter (2) aufweist.
3. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, daß die Gießform ferner eine Speiseraufweitung aufweist, wobei die Leitung durch die
Speiseraufweitung hindurchführt und dort eine erheblich größere Querschnittsfläche
als die der Leitung am Skin-Filter (2) aufweist.
4. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Leitung einen Eingußspeiser (5) aufweist, wobei die Gießform weiterhin eine Speiseraufweitung
(46) hat, die Leitung durch diese hindurchführt und dort eine wesentlich größere Querschnittsfläche
als die der Leitung am Skin-Filter aufweist.
5. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Schließeinrichtung wenigstens ein derart aufgebautes und geformtes Schließ-Schwimmteil
(28) aufweist, daß es schwimmt, wenn der Hohlraum (1) gefüllt ist, wobei das Schließ-Schwimmteil
in einer Öffnung (6) des Skin-Filters angeordnet ist und die Öffnung teilweise aber
nicht völlig blockiert und dadurch einen Durchgangsbereich mit reduzierter Querschnittsfläche
(28), gebildet durch die Einheit aus Schließ-Schwimmteil und Skin-Filter (2) bildet,
wobei das Schließ-Schwimmteil so angeordnet ist, daß es frei schwimmen kann, wenn
der Hohlraum voll ist, und so die wirksame Querschnittsfläche vergrößert, die für
das Auffüllen des Gußstücks durch die Öffnung, in dem das Schließ-Schwimmteil angeordnet
wurde, verfügbar ist, wobei das Schließ-Schwimmteil so ausgebildet ist, daß es der
durch das Gießen des geschmolzenen Metalls hervorgerufenen Wirkung von Temperatur,
Stoß, Druck und Erosion standhalten kann.
6. Vorrichtung nach Anspruch 5, dadurch gekennzeichnet, daß die Schließeinrichtung weiterhin eine Abdeckeinrichtung (11) aufweist, die in der
Leitung angeordnet ist, um zeitweise und weiterhin wenigstens einen Teil des Durchgangsberichs
mit verminderter Querschnittsfläche (29), gebildet durch die Anordnung aus Skin-Filter
(2) und Schließ-Schwimmteil (28), blockiert.
7. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß die Abdeckeinrichtung (11) in Kontakt mit dem Gußhaut-Filtrierensatz (2) angeordnet
ist und eine Anzahl von dessen Öffnungen (12) schließt.
8. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß die Abdeckeinrichtung (11) in Kontakt mit dem Schließ-Schwimmkörper (28) angeordnet
ist.
9. Vorrichtung nach Anspruch 8, dadurch gekennzeichnet, daß der Schließ-Schwimmkörper einen darin gebildeten Durchgang (29) aufweist, der die
Leitung (5) und den Formhohlraum (1) miteinander verbindet und wenigstens einen Teil
des Durchgangsbereichs mit verminderter Querschnittsfläche der Einheit aus Skin-Filter
und Schwimmkörper bildet, wobei die Abdeckeinrichtung (11) eine Einrichtung zum wenigstens
teilweisen Blockieren des Durchgangs in dem Schließ-Schwimmkörper aufweist.
10. Vorrichtung nach Anspruch 9, dadurch gekennzeichnet, daß die Abdeckeinrichtung des Skin-Filters (2) eine einzige Öffnung aufweist und in dem
Durchgang des Schwimmkörpers aufgenommen ist.
11. Vorrichtung nach Anspruch 10, dadurch gekennzeichnet, daß die Abdeckung (11) in dem Durchgang des Schwimmkörpers derart aufgenommen ist, daß
wenigstens ein Kanal zwischen dazwischen gebildet wird, der die Leitung mit dem Formhohlraum
verbindet.
12. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Filtriereinsätze wenigstens ein derart aufgebauten und geformten nicht schwimmenden
Körper (28) aufweist, der nicht schwimmt, wenn der Hohlraum voll ist, wobei der nicht
schwimmende Körper in einer Öffnung des Skin-Filters angeordnet ist und die Öffnung
teilweise aber nicht völlig blockiert und dadurch einen Durchgangsbereich mit reduzierter
Querschnittsfläche, geformt durch die Einheit aus nicht schwimmendem Körper und Skin-Filter,
bildet, wobei der nicht schwimmende Körper eine Ausnehmung (35) aufweist, die so angeordnet
ist, daß sie sich mit geschmolzenem Metall füllt, wobei die Ausnehmung eine Einrichtung
zur Bildung einer Wärmequelle von heißem Metall aufweist, das wärmemäßig in der Nähe
des Metalls in dem Durchgangsbereich mit reduzierter Querschnittsfläche (2) der Einheit
liegt, um die Auffüllkapazität des Durchgangsbereichs mit reduzierter Querschnittsfläche
zu erhöhen.
13. Vorrichtung nach Anspruch 12, dadurch gekennzeichnet, daß die Schließ-Einrichtung weiterhin eine Abdeckung (11) aufweist, die in der Leitung
angeordnet ist, um zeitweise und weiter wenigstens einen Teil des Durchgangsbereichs
mit reduzierter Querschnittsfläche, gebildet durch die Einheit aus Gußhaut-Filtrierstück
und nicht schwimmendem Körper, zu blockieren.
14. Vorrichtung nach Anspruch 13, dadurch gekennzeichnet, daß die Abdeckung in Kontakt mit dem Skin-Filter (2) angeordnet ist und eine Anzahl von
dessen Öffnungen (12) blockiert.
15. Vorrichtung nach Anspruch 13, dadurch gekennzeichnet, daß die Abdeckeinrichtung in Kontakt mit dem nicht schwimmenden Körper angeordnet ist.
16. Vorrichtung nach Anspruch 15, dadurch gekennzeichnet, daß das Nicht schwimmenden Körper einen darin ausgebildeten Durchgang hat, der die Leitung
(5) mit dem Formhohlraum (1) verbindet und wenigstens einen Teil des Druchgangsbereich
mit reduzierter Querschnittsfläche der Einheit bildet, wobei die Abdeckung (11) Vorrichtungen
zum wenigstens teilweisen Blockieren des Durchgangs in dem nicht schwimmenden Körper
aufweist.
17. Vorrichtung nach Anspruch 17, dadurch gekennzeichnet, daß die Öffnungseinrichtung des Skin-Filters (2) eine einzige Öffnung aufweist, wobei
die Abdeckung in dem Durchgang des nicht schwimmenden Körpers aufgenommen ist.
18. Vorrichtung nach Anspruch 17, dadurch gekennzeichnet, daß die Abdeckung in dem Durchgang des nicht schwimmenden Körpers derart aufgenommen
wird, daß wenigstens ein Kanal, der die Leitung mit dem Hohlraum verbindet, dazwischen
gebildet wird.
19. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Schließ-Vorrichtung eine Abdeckung (11) aufweist, die zum teilweisen Blockieren
von wenigstens einem Teil der gesamten Durchgangsquerschnittsfläche des Skin-Filters
in Kontakt mit diesem (2) angeordnet ist.
20. Vorrichtung nach Anspruch 19, dadurch gekennzeichnet, daß die Abdeckung (11) wenigstens eine Positionierfläche aufweist, die mit einer Seitenwand
(32) der Öffnungseinrichtung des Skin-Filters zusammenwirkt, um die Abdeckung während
des Füllens in Position zu halten.
21. Vorrichtung nach Anspruch 20,
dadurch gekennzeichnet, daß die Abdeckeinrichtung weiterhin aufweist:
- einen vorgefertigen Standardkörper (18) aus feuerfestem Material, auf dem die wenigstens
eine Positionierfläche gebildet ist, wobei sich an der Unterseite des Körpers eine
Ausnehmung befindet und ein durch die Länge des Körpers hindurchgehendes und mit der
Ausnehmung zusammenwirkendes Loch befinden;
- ein vorgefertigter Standard-Metallstab (22) mit einem Kopf an einem Ende und einem
Stegelement am anderen Ende, wobei der Stab in dem Loch so angeordnet ist, daß sich
der Kopf in der Ausnehmung befindet;
- ein vorgefertigtes Standard-Befestigungselement (13), das die Stange am Körper fixiert,
wobei die Stange eine Anhebvorrichtung aufweist; und
- feuerfestes Zusatzmischgut (27), das den verbleibenden Platz in der Aussparung füllt
und, wenn erforderlich, den Kopf der Stange bedeckt und der äußeren Kontur des Körpers
entspricht.
22. Vorrichtung nach Anspruch 21, dadurch gekennzeichnet, daß die Abdeckung weiterhin wenigstens eine vorgefertigte Standard-Zusatzabdeckungsverlängerung
(19) aus feuerfestem Material aufweist, die ein sich der Länge nach erstreckendes
Verlängerungsloch aufweist, wobei sich die Metallstange durch das Verlängerungsloch
hindurch erstreckt.
23. Vorrichtung nach Anspruch 20, dadurch gekennzeichnet, daß die Öffnungseinrichtung des Skin-Filters eine einzige Öffnung (12) aufweist, wobei
die Positionierfläche der Abdeckung darin angeordnet ist.
24. Vorrichtung nach Anspruch 23, dadurch gekennzeichnet, daß die Positionierfläche (15) so zu einer Wand der Öffnung paßt, daß wenigstens ein
Kanal dazwischen gebildet wird, der die Leitung und den Formhohlraum verbindet.
25. Vorrichtung nach einem der Ansprüche 5, 12 oder 19, dadurch gekennzeichnet, daß die Schließ-Vorrichtung wenigstens einen so aufgebauten und geformten Blind-Schwimmkörper
(57), daß er schwimmt, wenn der Hohlraum gefüllt ist, und Vorrichtungen zum Halten
des Blind-Schwimmkörpers aufweist, so daß er sich beim anfänglichen Gießen des geschmolzenen
Metalls in die Leitung nicht wesentlich bewegt, aber dennoch frei zum Schwimmen ist,
wenn der Formhohlraum gefüllt ist, und es so ermöglicht, daß die Gußform durch die
Öffnung, die durch den Blind-Schwimmkörper geschlossen gewesen war, aufgefüllt wird,
wobei der Blind-Schwimmkörper so ausgebildet ist, daß er der durch das Gießen des
geschmolzenen Metalls hervorgerufenen Einwirkung von Temperatur, Stoß, Druck und Erosion
standhalten kann.
26. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß sie ein in der Leitung angeordnetes metallurgisches Behandlungsprodukt aufweist,
das Mittel zum Behandeln des geschmolzenes Metalls in der Leitung umfaßt.
27. Schwerkraft-Gießform nach Anspruch 1-26, dadurch gekennzeichnet, daß das Eingußsystem einen einstückig aus dem Gußmaterial geformten Kragen (52) aufweist,
der zwischen der Leitung und dem Formhohlraum so dazwischengesetzt ist, daß eine Fläche
des Kragens eine Fläche des Hohlraums ist, wobei eine Öffnung die Verbindung zwischen
der Leitung und dem Formhohlraum an der Stelle des Kragens bildet.
28. Vorrichtung nach Anspruch 27, dadurch gekennzeichnet, daß sie einen Kragenrand aufweist, der von der Gießform und der Schließ-Vorrichtung abgesetzt
ist, wobei der Kragen den Einsatz trägt und die Öffnung durch den Einsatz hindurchgeht.
29. Vorrichtung nach Anspruch 27, dadurch gekennzeichnet, daß die Leitung einen Eingußspeiser aufweist, wobei die Gießform eine Speiserverlängerung
aufweist, die Leitung durch die Verlängerung (46) hindurchführt und darin im wesentlichen
dieselbe Querschnittsfläche wie die der Leitung am Kragen aufweist.
30. Vorrichtung nach Anspruch 29, dadurch gekennzeichnet, daß die Gießform weiterhin eine Speiseraufweitung (47) umfaßt, wobei die Leitung durch
die Aufweitung hindurchführt und darin eine wesentlich größere Querschnittsfläche
als die der Leitung am Kragen hat.
31. Vorrichtung nach Anspruch 27, dadurch gekennzeichnet, daß die Leitung einen Eingußspeiser umfaßt, wobei die Gießform weiterhin eine Speiserverlängerung
aufweist und dabei eine wesentlich größere Querschnittsfläche als die der Leitung
am Kragen hat.
32. Vorrichtung nach Anspruch 27, dadurch gekennzeichnet, daß sie ein in der Leitung angeordnetes metallurgisches Behandlungsprodukt aufweist,
wobei das Produkt Mittel zur Behandlung des geschmolzenen Metalls in der Leitung umfaßt.
33. Schwerkraft-Gießform nach Anspruch 1-32, dadurch gekennzeichnet, daß einer der Filter entlang der Länge der Leitung angeordnet ist.
34. Vorrichtung nach einem der Ansprüche 1 oder 27, dadurch gekennzeichnet, daß der Filter ein Lochblech (68) aus feuerfestem Material umfaßt.
35. Vorrichtung nach einem der Ansprüche 1 oder 27, dadurch gekennzeichnet, daß die Schließ-Vorrichtung ein mit Löchern versehenes feuerfestes Material umfaßt.
36. Vorrichtung nach einem der Ansprüche 1 oder 27, dadurch gekennzeichnet, daß die Schließ-Vorrichtung aus einem Werkstoff gefertigt sind, der den durch das Gießen
des geschmolzenen Metalls hervorgerufenen Einwirkungen von Temperatur, Stoß, Druck
und Erosion standhalten kann.
37. Vorrichtung nach einem der Ansprüche 1 oder 27, dadurch gekennzeichnet, daß die Schließ-Vorrichtung vorgefertigte Standardbauteile umfaßt.