U.S. patent application number 11/547413 was filed with the patent office on 2008-10-30 for shield feeder or plug feeder.
Invention is credited to Udo Skerdi.
Application Number | 20080265129 11/547413 |
Document ID | / |
Family ID | 35034151 |
Filed Date | 2008-10-30 |
United States Patent
Application |
20080265129 |
Kind Code |
A1 |
Skerdi; Udo |
October 30, 2008 |
Shield Feeder or Plug Feeder
Abstract
The invention relates to a feeder insert for inserting into a
casting mold used for casting metals, comprising a feeder body 1,
which extends along a longitudinal axis 13 of the feeder and has a
feeder cavity 2, comprising a bottom side that can be inserted into
the casting mold and a top side 7 that is situated opposite the
bottom side. According to the invention, an energy absorbing device
(8, 9) is provided on the top side 7 of the feeder body 1.
Inventors: |
Skerdi; Udo; (Bendorf/Rhein,
DE) |
Correspondence
Address: |
SCOTT R. COX;LYNCH, COX, GILMAN & MAHAN, P.S.C.
500 WEST JEFFERSON STREET, SUITE 2100
LOUISVILLE
KY
40202
US
|
Family ID: |
35034151 |
Appl. No.: |
11/547413 |
Filed: |
April 1, 2005 |
PCT Filed: |
April 1, 2005 |
PCT NO: |
PCT/EP05/03429 |
371 Date: |
July 19, 2008 |
Current U.S.
Class: |
249/204 |
Current CPC
Class: |
B22C 9/088 20130101 |
Class at
Publication: |
249/204 |
International
Class: |
B22D 41/16 20060101
B22D041/16 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 2, 2004 |
DE |
10 2004 017 062.2 |
Claims
1. A feeder insert for inserting into a casting mold used for
casting metals, comprising a feeder body, which extends along a
longitudinal axis of the feeder insert and comprises a feeder
cavity, a bottom side in communication with the casting mold, and a
top side that is situated opposite the bottom side, and an energy
absorbing device provided on the top side of the feeder body.
2. The feeder insert as claimed in claim 1, characterized in that
the energy absorbing device covers at least the top side of the
feeder body.
3. The feeder insert as claimed in claim 1, characterized in that
the energy absorbing device comprises a deformation element.
4. The feeder insert as claimed in claim 1, characterized in that
the energy absorbing device comprises an elastic element.
5. The feeder insert as claimed in claim 1, characterized in that
the energy absorbing device comprises a friction element.
6. The feeder insert as claimed in claim 1, characterized in that
the energy absorbing device comprises a plate-shaped element which
is arranged generally perpendicular to the longitudinal axis of the
feeder insert.
7. The feeder insert as claimed in claim 6, characterized in that
the plate-shaped element has at least one continuation element and
the feeder body has at least one depression extending inward from
the top side of the feeder body into which the continuation element
is received.
8. The feeder insert as claimed in claim 7, characterized in that
the continuation element comprises a rod-shaped plug element and
the depression comprises a sleeve.
9. The feeder insert as claimed in claim 8, wherein ridges are that
arranged along a wall of the sleeve such that their diameter within
the sleeve decreases as they extend into the feeder body from the
topside of the feeder body.
10. The feeder insert as claimed in claim 8, wherein the sleeve
further comprises a spring element which produces a counterforce
when the rod-shaped plug element is inserted into the sleeve.
11. The feeder insert as claimed in claim 1, characterized in that
the energy absorbing device further comprises a skirt (11) which
reaches around the upper circumference of the feeder body.
12. The feeder insert as claimed in claim 1, wherein the feeder
body further comprises a constriction on or near the bottom side of
the feeder body to form a breaking edge.
13. The feeder insert of claim 6 wherein the plate shaped element
extends outward at least to a maximum cross section of the feeder
body.
14. The feeder insert of claim 9 wherein a diameter of the plug
element is smaller than the diameter of the sleeve.
15. A feeder insert for inserting into a casting mold used for
casting metal comprising a feeder body which comprises a feeder
cavity, a bottom side, a top side and an energy absorbing device
introduced into one or more sleeves in the top side of the feeder
body.
16. The feeder insert as claimed in claim 15, characterized in that
the energy absorbing device comprises a deformation element.
17. The feeder insert as claimed in claim 15 characterized in that
the energy absorbing device comprises an elastic element.
18. The feeder insert as claimed in claim 15, characterized in that
the energy absorbing device comprises a friction element.
19. The feeder insert as claimed in claim 15, wherein the sleeve
further comprises a spring element which produces a counterforce
when the energy absorbing device is inserted into the sleeve.
20. The feeder insert as claimed in claim 15, wherein the feeder
body further comprises a constriction on or near the bottom side of
the feeder body which forms a breaking edge.
Description
[0001] The invention relates to a feeder insert for inserting into
a casting mold used for casting metals, comprising a feeder body,
which extends along a main axis of the feeder and has a feeder
cavity, comprising a bottom side that can be inserted into the
casting mold and a top side that is situated opposite the bottom
side.
[0002] In the production of molded parts in a foundry, liquid metal
is introduced into a casting mold. During the solidifying process,
the volume of the material introduced decreases. Therefore,
so-called feeders, i.e. open or closed spaces, are regularly
inserted in or on the casting mold in order to compensate for the
volume deficit during the solidification of the casting and to
prevent the formation of voids in the casting. For this purpose,
the feeders are connected to the casting or to the region of the
casting that is at risk and are usually arranged above or to the
side of the mold cavity.
[0003] In the production of the casting mold, firstly a pattern
plate which corresponds to the inner contour of the mold cavity is
produced. At the locations at which a feeder insert is to be
fitted, a holding device is usually provided, for example a pin for
fixing the position of the feeder insert. Once the feeders are
fitted on the pattern plate, a molding material, generally molding
sand, is applied to the pattern plate in such a way that the feeder
insert is encapsulated. In a further step, the molding material is
then compacted, so that the feeder is enclosed by the compacted
molding material. During the compaction of the molding material,
relatively high compaction pressures are used. There is therefore
the risk that the feeder insert will not withstand the compressive
forces occurring during the compaction and will break up. As a
result, it is no longer possible for controlled feeding of the
casting to take place during the casting process. It has been
attempted to counter this problem by using particularly stable and
thick-walled feeder inserts. However, this is quite expensive
because of the increased material requirement.
[0004] Another approach is to absorb the compressive forces
occurring during the compression molding by means of so-called
expansion mandrels. Expansion mandrels generally comprise a tubular
element for fastening on the pattern plate, a spring arranged in
the tubular element and a mandrel tip element, which rests on the
spring and can be displaced telescopically in the longitudinal
direction. After the expansion mandrel is fastened on the pattern
plate, a feeder insert is placed on it, the bottom surface of which
is at a certain distance from the surface of the pattern in the
initial arrangement, i.e. before the molding material is
introduced. During the subsequent introduction and compaction of
the molding material, the feeder insert is moved in the direction
of the surface of the pattern against the spring force exerted by
the expansion mandrel, without the bottom side of the feeder insert
coming into direct contact with the surface of the pattern.
[0005] Therefore, destruction of the feeder insert is prevented
even when high compaction forces are used.
[0006] A sprung mandrel for holding feeders and comprising a
holding and guiding part, a spring and an axially movable cover is
described in DE 41 19 192 A1. The cover is formed like a cup and
extends over the spring and the holding and guiding part.
[0007] An arrangement comprising a cup-shaped feeder and a mandrel
is described in DE 195 03 456 C1. The mandrel is fastened on a
casting pattern. The feeder is mounted on the mandrel in such a way
that a distance is maintained between its lower end and the surface
of the casting pattern. A first and a second rigidly preset stop
are preset on the mandrel for a first and a second
distance-maintaining position. The feeder assumes the second
distance-maintaining position, near the surface of the casting
pattern, during the compaction of the molding sand, by a
predetermined breaking point in the bottom of the feeder being made
to open by the counter pressure emanating from the mandrel,
allowing the feeder to go over into the second distance-maintaining
position.
[0008] Before the feeder inserts are inserted, the expansion
mandrels must first be fastened on the pattern plate, which is a
laborious procedure. Furthermore, with an expansion mandrel, a
precisely arranged knock-off edge can only be realized with
difficulty. This knock-off edge is provided to make it possible for
the residual feeder, i.e. the metal remaining in the feeder insert
after casting, to be separated from the casting. The cleaning
effort is therefore generally quite high. Expansion mandrels are
also quite expensive and susceptible to wear.
[0009] The invention was therefore based on the object of providing
a feeder insert which can withstand the forces occurring during the
compaction of the molding material. Furthermore, at least in a
preferred embodiment of the feeder insert, it should be possible to
provide a knock-off edge which makes it possible for the residual
feeder to be precisely separated from the casting.
[0010] This object is achieved by a feeder insert with the features
of patent claim 1. Advantageous embodiments are the subject of the
dependent claims.
[0011] The feeder insert according to the invention comprises a
feeder body, in which a feeder cavity is arranged. The feeder body
may in fact be of any desired form and is formed in the customary
way. The feeder body usually has an approximately tubular form. The
feeder thereby has a height which is greater than its diameter. The
feeder body may for example be cylindrically formed. However, it is
also possible that the feeder body tapers for example toward the
bottom side, so that a small standing surface of the feeder insert
on the pattern plate is achieved. The feeder body has on its bottom
side an opening through which the feeder cavity is in connection
with the cavity of the casting mold. The feeder body may likewise
be open on its top side. However, it may equally be closed on its
top side. The feeder body consists of the materials that are
customary for the production of feeders and may be formed in an
insulating and/or exothermic manner. Appropriate materials are
known to a person skilled in the art. According to the invention,
an energy absorbing device is provided on the top side of the
feeder body. The feeder insert is fitted directly on the surface of
the pattern plate, so that in a preferred embodiment a breaking
edge can be created at the lower termination of the feeder insert.
An energy absorbing device, which absorbs the forces or energy
acting on the feeder insert during the compaction of the molding
material, is provided on the top side of the feeder insert. This
avoids the feeder body being compressed by the forces acting during
the compaction and thereby broken up. The feeder therefore does not
require an expansion mandrel to absorb the forces acting during the
compaction of the molding material. However, it may be advisable to
provide a fixed mandrel for positioning and fixing the feeder
insert according to the invention.
[0012] The energy absorbing device preferably covers at least the
top side of the feeder body. In this way, forces which act in the
direction of the pattern plate parallel to the longitudinal axis of
the feeder body can be substantially absorbed or at least
significantly reduced. Since the energy absorbing device covers the
entire top side of the feeder body, shearing off of parts of the
feeder body during the compaction of the molding material can also
be prevented.
[0013] The energy absorbing device may be formed in various ways.
For instance, according to a first embodiment, the energy absorbing
device may comprise a deformation element. The irreversible
deforming of the deformation element has the effect that the force
which acts on the top side of the feeder body during the compaction
of the molding material is absorbed and the energy introduced is
destroyed, so that no damage to the feeder body can occur. The
deformation element may be formed in various ways. In a very simple
embodiment, the deformation element may for example be a plate
which is produced from a suitable deformable material, for example
a rigid foam. Such a rigid foam may be a polymer foam, such as for
example a polystyrene foam, or else a foam of an inorganic
material, for example a foamed glass. The deformation element may
also consist of metal and have a form which makes it possible to
absorb energy by deforming of the deformation element. For example,
the deformation element may be formed in a way similar to a can,
the side walls being folded like an accordion. The can is
compressed during the pressing of the molding material, by the
accordion structure being further pressed together. Other
structures are also possible. For example, it is conceivable that
the deformation element has a honeycomb structure which is
compressed under the action of the forces acting during the
compression molding.
[0014] According to another embodiment, the energy absorbing device
is formed as an elastic element. For this purpose, the energy
absorbing device may for example comprise a spring element which is
compressed during the pressing of the molding material, in order in
this way to absorb the forces acting on the feeder body. However,
other elastic elements may also be used. For example, it is also
possible to use a rubber ring or a rubber plate which absorbs
energy introduced into the feeder body by elastic deformation.
[0015] The energy absorbing device may also comprise a friction
element. The energy introduced into the energy absorbing device
during the compression molding is then converted into heat by the
friction between two appropriately formed surfaces and is
destroyed.
[0016] The energy absorbing device may be formed in various ways.
In a preferred embodiment, it comprises a plate-shaped element
which is arranged substantially perpendicular to the longitudinal
axis of the feeder and has an extent which corresponds at least to
the cross section of the top side of the feeder body. In the
simplest embodiment, the energy absorbing device is for example a
plate, for example a plate which can be deformed in the direction
of the longitudinal axis of the feeder and is placed on the top
side of the feeder body. The plate-shaped element may, however,
also be formed in such a way that it has the form of a cap. In this
embodiment, the plate-shaped element comprises a skirt running
along its periphery that preferably reaches over the edge running
around the circumference of the top side of the feeder body, in the
direction of the side face of the feeder body, in the case where
the plate-shaped element is resting on the top side of the feeder
body. This facilitates the fixing of the energy absorbing device on
the top side of the feeder body. The top side and bottom side of
the plate-shaped element may be formed as substantially parallel
running surfaces. However, the plate-shaped element may also have
for example a greater thickness in the middle of its surface than
at the periphery, so that the energy absorbing device is given a
roof-shaped form.
[0017] In a preferred embodiment, the plate-shaped element has at
least one continuation and the feeder body has on the top side at
least one receptacle in which the continuation is received. The
continuation may be formed, for example, as a peripheral ring on
the bottom side of the plate-shaped element, which is inserted in a
groove formed on the top side of the feeder body in the form of a
peripheral circle. This allows the plate-shaped element to be fixed
for example in a position such that it is not displaced during the
introduction of the molding material and the subsequent
compaction.
[0018] However, the continuation is formed with preference as a
rod-shaped plug element and the receptacle is formed with
preference as a sleeve. With preference, at least two rod-shaped
plug elements, but with particular preference three or four or more
plug elements, are provided on the side of the plate-shaped element
that is facing the feeder body. The length of the plug elements may
be chosen to be very short if the plugs merely serve for fixing the
position of the energy absorbing device. However, the rod-shaped
plug elements are used with preference in cooperation with the
sleeves introduced into the feeder body for absorbing and
destroying the energy which is introduced into the feeder body
during the compression molding. The sleeves may be produced as a
separate component which is produced for example from plastic or
metal and introduced into the feeder body. However, it is also
possible to form the feeder body directly in such a way that
corresponding depressions on the top side are formed directly in
the material of the feeder body.
[0019] As already explained, the rod-shaped plug elements may be
used in cooperation with the sleeves for absorbing and destroying
energy which would otherwise bring about a compression of the
feeder body, which may lead to the breaking up of the feeder
body.
[0020] In a first embodiment, arranged for this purpose along the
wall of the sleeve are projections by which the diameter of the
sleeve is reduced to the extent that it becomes slightly smaller
than the diameter of the rod-shaped plug element. The projections
may be formed for example as ridges which run in the direction of
the longitudinal axis of the feeder body along the wall of the
sleeve. If the rod-shaped plug elements of the plate-shaped element
are inserted into the sleeve, the plate-shaped element is initially
kept at a specific distance from the top side of the feeder body.
If molding material is then introduced around the feeder insert and
subsequently compacted, the plate-shaped element is moved in the
direction of the longitudinal axis of the feeder body toward the
top side of the feeder body. The rod-shaped plug elements thereby
deform the projections arranged along the wall of the sleeve, so
that energy which would otherwise lead to compression of the feeder
body is absorbed on the one hand by the deformation and on the
other hand by the friction between the sleeve and the rod-shaped
plug element.
[0021] According to another embodiment, a spring element which
produces a counterforce when the rod-shaped plug element penetrates
the sleeve may also be provided in the sleeve. Energy which could
otherwise bring about a compression of the feeder body is once
again absorbed by the pressing together of the spring element. The
spring element may also be formed in such a way that it presses
against the side faces of the rod-shaped plug element and thereby
brings about a high degree of friction between the spring element
and the rod-shaped plug element.
[0022] In a preferred embodiment, the energy absorbing device has a
skirt which reaches around the circumference of the feeder body and
has in a direction perpendicular to the bottom side of the
plate-shaped element an extent which corresponds at least to the
length of the rod-shaped plug elements. In this way, grains of
molding material are prevented from penetrating into a spacing
between the top side of the feeder body and the bottom side of the
energy absorbing device during the introduction of the molding
material and falling from there for example into the feeder
cavity.
[0023] According to a further preferred embodiment, a constriction
is provided on or near the bottom side of the feeder body to form a
breaking edge. Since the feeder insert according to the invention
can be placed directly on the pattern plate, the position of the
constriction in relation to the surface of the casting is defined,
so that a breaking edge for the knocking off of the residual feeder
can be arranged at a specific position. As a result, the effort
required for cleaning the surface of the casting after the residual
feeder has been knocked off is significantly reduced.
[0024] The invention is explained in more detail below with
reference to an accompanying drawing. The same items are provided
with the same designations. In the figures specifically:
[0025] FIG. 1 shows a cross section through a feeder insert
according to the invention before compaction;
[0026] FIG. 2 shows a cross section through the feeder insert
represented in FIG. 1 after compaction;
[0027] FIG. 3 shows a longitudinal section through a further
embodiment of the feeder insert according to the invention before
compaction;
[0028] FIG. 4 shows a longitudinal section and a cross section
through a sleeve introduced into the top side of the feeder body;
and
[0029] FIG. 5 shows a longitudinal section through a second
embodiment of a sleeve introduced into the top side of the feeder
body.
[0030] FIG. 1 shows a longitudinal section through a first
embodiment of the shield feeder or plug feeder according to the
invention along a longitudinal axis 13 of the feeder. The feeder
insert comprises a feeder body 1, which encloses a feeder cavity 2.
Provided toward the bottom side of the feeder body is an insert 3,
by which a constriction can be formed to form a breaking edge. The
insert 3 consists for example of steel sheet, wood or similar
material. The feeder cavity 2 ends in an outlet opening 4, via
which the feeder cavity 2 is in connection with the cavity of the
casting mold. For the production of the casting mold, a pattern
plate 5 takes the place of the cavity of the casting mold. Led
through the outlet opening 4 is a mandrel 6, which is fastened on
the pattern plate 5 and by which the feeder body 1 is fixed in its
position. On the top side 7 of the feeder body 1, two depressions 8
in the form of a sleeve are introduced into the feeder body 1. The
sleeve may be produced from metal, wood, plastic or similar
materials and be inserted in corresponding depressions in the
feeder body 1. However, the sleeve may also be formed directly in
the material of the feeder body. Inserted respectively in the
depressions 8 are rod-shaped plugs 9, which carry a plate-shaped
element 10. The diameter of the plugs corresponds approximately to
the diameter of the depressions 8. Devices which prevent the
rod-shaped plugs 9 from penetrating completely into the depressions
8 are provided in the depressions 8. As a result, the plate-shaped
element 10 is kept at a specific distance from the top side 7 of
the feeder body 1. Provided along the outer circumference of the
plate-shaped element 10 is a skirt 11, which is chosen to be of
such a size that no molding material can penetrate into the
intermediate space between the plate-shaped element 10 and the top
side 7 of the feeder body 1 during the introduction of molding
material. As a result, the plate-shaped element 10 comprises a
shield- or boss-like form. The plate-shaped element 10 and the
skirt 11 consist for example of steel sheet, wood, plastic or
similar materials. Since the feeder insert is fixed on the pattern
plate 5, molding material 12 is arranged around the feeder insert
and compacted. The forces acting during the compaction have the
effect that the plate-shaped element 10 is displaced in the
direction of the longitudinal axis 13 of the feeder toward the top
side 7 of the feeder body 1. As a result, the rod-shaped plugs 9
penetrate into the depressions 8. Interactions between the
rod-shaped plug 9 and the sleeve 8 have the effect that energy is
destroyed, for example by friction or deformation, and so prevent
the feeder body 1 from being compressed. In the case of the
embodiment represented in FIG. 2, after compaction the plate-shaped
element 10 rests on the top side 7 of the feeder body 1. The feeder
insert is surrounded on all sides by compacted molding material 12.
Subsequently, the mandrel 6 and the pattern plate 5 are also
removed, so that the casting mold is obtained. Arranged at the
transition between the feeder cavity 2 and the cavity of the
casting mold is a constriction 14, which after casting serves as a
breaking edge for knocking off a residual part of the feeder.
[0031] In FIG. 3, a further embodiment of the feeder insert
according to the invention is represented in longitudinal section.
In the case of this embodiment, apart from the outlet opening 4
arranged on the bottom side, the feeder body 1 has an opening 15 in
the top side of the feeder body 1. The embodiment represented in
FIG. 3 is therefore formed as an open shield feeder or plug feeder.
As in the case of the embodiment represented in FIGS. 1 and 2,
depressions 8 are introduced into the top side 7 of the feeder body
1. The rod-shaped plugs 9 of the plate-shaped element 10 are
inserted in these depressions. Molding material is then introduced
around the feeder insert, as explained with respect to FIGS. 1 and
2, and this material is subsequently compacted. In this case, the
plate-shaped element 10 is moved in the direction of the
longitudinal axis 13 of the feeder toward the top side 7 of the
feeder body 1. By interaction between the rod-shaped plug 9 and the
depression 8, the force acting on the feeder body 1 in the
direction of the longitudinal axis 13 of the feeder during the
compaction of the molding material is absorbed and the energy is
consumed, so that no compression of the feeder body 1 takes place
and significantly higher forces can be used for the compression
molding.
[0032] FIG. 4 shows a preferred embodiment of the depressions 8.
Starting from the top side 7 of the feeder body, a depression 8 is
introduced into the feeder body 1. FIG. 4b shows a longitudinal
section through the depression 8 along a longitudinal axis 16.
Arranged along the wall of the depression 8 are ridges 17, by which
the cross section of the depression 8 is constricted. The ridges 17
run parallel to the longitudinal axis 16, the thickness of the
ridges, i.e. their extent into the interior space of the depression
8, increasing as they become increasingly further away from the
surface 7. In FIG. 4a, a cross section along the line a-a, shown in
FIG. 4b, is represented.
[0033] It can be seen that a number of ridges 17 are arranged on
the outer wall of the depression 8, whereby the cross section of
the depression 8 is constricted. If a rod-shaped plug 9 (not shown)
is then inserted into the depression 8, it can initially be pushed
into the depression 8 only to a certain depth. When pushed in
further, a frictional force is produced between the ridges 17 and
the wall of the rod-shaped plug 9. In this case, the ridges 17 may
also be deformed. When this happens, energy is consumed, so that
the force exerted on the plate-shaped element by the compaction of
the molding material is absorbed and the energy introduced can be
destroyed. The embodiment of the depression 8 represented in FIG. 4
can be obtained by the appropriate structure being formed directly
in the material of the feeder body 1. However, it is also possible
to produce an appropriate sleeve, which is then inserted into a
corresponding depression in the feeder body 1.
[0034] In FIG. 5, a further embodiment of the depression 8 is
represented as a longitudinal section. Inserted in the depression 8
is a sleeve 18, the wall of which runs along the wall of the
depression 8. The sleeve 18 may also have a collar 19, which rests
on the top side 7 of the feeder body 1. Spring elements are
arranged in the sleeve 18. These may be constructed for example
from spring steel or plastic. The spring elements 20 can be moved
with their one end in the direction of the wall of the sleeve 18,
which is represented by the arrow 21. If a rod-shaped plug element
9 (not shown) is then inserted into the interior space of the
sleeve 18, it initially comes to bear against the spring elements
20. If pressure is then exerted on the rod-shaped plug elements 9
in the direction of the longitudinal axis 16, the spring elements
20 are pivoted at their lower termination in the direction of the
wall of the sleeve 18. They thereby oppose the movement of the
rod-shaped plug elements with a counterforce, whereby the force
exerted on the plate-shaped element 10 (not shown) is absorbed and
the energy introduced is destroyed. The sleeve 18 may be produced
from any suitable material. Suitable materials are, for example,
steel or plastic.
* * * * *