Information
-
Patent Grant
-
6460605
-
Patent Number
6,460,605
-
Date Filed
Friday, April 21, 200024 years ago
-
Date Issued
Tuesday, October 8, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Elve; M. Alexandra
- Tran; Len
Agents
- Flynn, Thiel, Boutell & Tanis, P.C.
-
CPC
-
US Classifications
Field of Search
US
- 164 133
- 164 136
- 164 335
- 164 329
- 164 322
- 164 119
- 164 306
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International Classifications
-
Abstract
A casting process for casting, in particular of sand molds provided with casting boxes, which makes it possible to keep the apparatus expense low, to save cycle material and to achieve an improved quality, consists of the intake channel extending in a plane lying essentially horizontally during casting and being provided with a bearing surface defining its port, onto which bearing surface can be sealingly positioned a fill pipeline through which the mold can be filled with metal under low pressure. A casting system to carry out the method consists of a casting machine with a pressure kettle and a fill pipeline which is connected to the intake channel lying essentially in a horizontal plane, whereby the sealed coupling of fill pipeline and intake channel is obtained through specified bearing pressure.
Description
FIELD OF THE INVENTION
The invention relates to an apparatus for filling of a mold and a casting system, whereby in particular a sand mold having a casting box with an upper and a lower mold half is used, and the mold has an intake channel connected in the dividing plane of both mold halves to the mold cavity. The apparatus can be utilized for the filling of both a mold without a box and also a mold provided with a casting box, which can be chemically bound and also clay-bound.
BACKGROUND OF THE INVENTION
Clay-bound sand molds are considerable less as expensive than chemically bound molds so that preferably clay-bound sand molds are used-in foundries. These clay-bound sand molds are as a rule manufactured in a casting box, which receives each a mold half. It is here known to construct the intake channel in the upper mold half, whereby the casting of the sand mold is particularly simple in constructional respects since the liquidy metal must merely be poured from an open casting pan into the mold. The intake channel extends hereby advantageously over the height of the mold so that the mold cavity is filled in a rising casting. Such a casting of the mold, however, has the significant disadvantage that the metal is poured into the mold from a certain height causing on the one hand a bothersome splattered iron leading to considerable breakdowns in automatically operating mold and casting systems. On the other hand, the unavoidably great casting height causes in these cases high ferro-static pressures in the sand molds, which can deform the sand molds and can also damage them due to turbulences created during-the casting. These disadvantages occur also in upright positioned molds, in-which the intake channel is either arranged in the mold-dividing plane of both molds or, however, on the upper side of the upper mold half.
For this reason it is already known to fill the molds from the underside, for example, by means of a low-pressure furnace, which has an uptake connected to the port of the intake channel. By increasing the pressure in the gas chamber of the low pressure furnace, the liquidy material is pressed through the uptake upwardly into the mold. The pressure must be maintained until the liquidy or molten material in the intake channel of the mold has solidified. The pressure in the low-pressure furnace is subsequently lowered and the still liquidy excessive material flows back into the low-pressure furnace. The mold can then be lifted off and moved on. Such a method has proven to be successful, however, it requires an expensive apparatus, especially since the positioning of the mold above the uptake and the recharging of the low-pressure furnaces demand a high degree of technology. These devices are also technically complicated since the mechanical parts lying below the plane of the mold are difficult to access and are thus difficult to service.
SUMMARY OF THE INVENTION
The basic purpose of the invention is to provide an apparatus to carry out the method and a suitable mold, which make it possible to keep down the level of technology and thus the investment expenses accordingly, which demand little service while at the same time providing high process safety and a precise repetitive exactness and significantly reduce the amount of the cycle material, save energy, avoid smoke development, eliminate a penetration formation caused by the height of casting, and moreover guarantee a calm, turbulence-free mold filling. A further purpose of the invention is to provide the casting system in such a manner that also existing casting systems can be retrofitted in a simple and inexpensive manner so that the method of the invention can be carried out with these casting systems.
This purpose is attained according to the invention in such a manner that the intake channel is arranged extending in a plane lying essentially horizontally during casting, and has a bearing surface defining its port, onto which bearing surface can be sealingly placed a fill pipeline, through which the mold can be filled with liquidy metal under low pressure.
Thus a mold is used which is divided in two, whereby the intake channel extends essentially-in the dividing plane, whereby the mold is arranged in such a manner during casting that the dividing plane lies. essentially horizontally. It may be advantageous for certain mold cavity designs to slightly incline the mold with respect to the horizontal in. order to achieve a calm and even filling of the entire mold cavity. The intake channel of the mold is designed in such a manner that a bearing surface for a fill pipe is constructed around its port, which fill pipe can be sealingly fitted to this bearing surface. It has hereby been determined that also in the case of clay-bound sand molds a flat bearing surface is already sufficient when same rests under a certain pressure on the port of the fill pipe in order to guarantee a metal-tight seal. The mold cavity can then be filled with a relatively small overpressure through the fill pipeline through the horizontally lying intake channel, whereby it has here been found to be advantageous when the fill pipeline is connected to a casting machine and terminates in the lower part of a pressure chamber. A fill chute can also terminate in this lower part of the chamber, the fill funnel of which fill chute must not be closed off when same lies above the maximum fill level of the pressure kettle. Such a casting machine makes it possible, corresponding with the respective requirements, to successively increase the fill pressure in the pressure kettle by increasing the pressure so that the mold cavity can be filled without any danger of penetration and free of turbulence. Two or more fill pipelines can be connected to a casting machine so that several molds can be filled simultaneously.
It has proven to be advantageous when the mold is moved toward the opening of the fill pipeline, whereby here a specified bearing pressure is adjusted, for example, by means of a moving cylinder. The casting boxes are supplied on a conventional floor-mounted conveyer with the mold-dividing plane lying. horizontally, on which floor-mounted conveyer the casting boxes are cyclically moved. A moving device is integrated into this floor-mounted conveyer, whereby one or more casting boxes are arranged simultaneously laterally movably so that they can be moved toward the mouthpiece of the casting machine in order to fill the mold. After the mold has been filled, the casting boxes are moved back to the floor-minted conveyor by the moving device and are moved on cyclically. The force with which the moving device is moved toward the casting machine is adjustable so that the bearing pressure of the bearing surface of the mold at the port of the fill pipeline can be adapted to the respective requirements.
Immediately after the mold has been filled, the intake channel is closed off by means of moving sand or core, whereby this sand or rather core movement is caused by a ram which presses sand into the cross section of the intake channel or, however, moves a core into said channel. Thus one must not wait here until the metal solidifies in the intake channel but the separation of the mold from the fill pipeline can occur directly after the intake channel has been closed off. This results in a significant decrease in the cycle time.
A filter is installed, according to a further suggestion of the invention, into the intake channel of the mold, namely in flow direction in front of the point at which the intake channel is closed off by sand or core movement, which filter prevents sand parts, which could come loose during closing, from reaching into the fill pipeline.
The casting system consists of a transport device for supplying and removing the casting boxes, a casting machine for filling the casting boxes, and a blocking device to block the intake channel of the mold following the casting, whereby the transport device houses a moving carriage, by means of which the casting box can be moved transversely with respect to the transport direction of the transport path toward the casting machine and back to the transport path, whereby through the movement of the casting box same can be moved closely toward an opening of a fill pipeline of the casting machine, and the metal can be pressed by means of the overpressure in the casting machine into the mold cavity of the mold.
The casting machine is advantageously one which has a pressure kettle, in the lower area of which terminate both the fill pipeline and-also a fill chute, through which material follows into the casting machine. The pressure kettle is closed off and is connected to a pressure-gas system so that upon an increase of the pressure in the pressure kettle the material in the fill pipeline and also in the fill chute increases. Since the fill-chute has a fill funnel, which lies above the maximum level of the fill level of the pressure kettle and also above the port of the fill pipeline, it is possible to recharge the casting machine at any time.
The intake channel lies in the mold in the mold-dividing plane of the upper and lower box, whereby here a recess exists in the casting box so that a bearing surface is here opened up directly in the mold. The recess is advantageously conical so that the guiding of the port of the head channel of the fill pipeline is made easier.
Because of the very sensitive dosable fill speed of the mold cavity, same can be designed without any kind of a vent bore so that the necessary finish work on the cast pieces and the cycle material are further reduced.
Based on the method of the invention a casting system is provided which requires only a low level of technology and thus also little investment expenses. Such a casting'system demands less service also because expensive dosing mechanisms are not needed. This means that an improvement of the availability of the system exists. Since we are here dealing with a closed fill system, also the heat loss is very low, thus resulting in a significant energy savings and moreover also a smoke development is avoided so that all in all better environmental conditions at the work station exist. Moreover, because of the closed system splattered iron also does not accumulate. Since dosing based on the low need for pressure for filling of the mold can be reached very exactly and reproducibly by simple means, a high process safety and a precise repetitive exactness is obtained. Moreover, the system makes it possible to store data so that the fill curves for each mold filling can be documented. Moreover, the system of the invention reduces the required cycle material, and penetration formations in the mold do not exist since here an energy entry caused by the casting height is avoided. Moreover, a very calm and turbulence-free mold filling is obtained. It is also advantageous that existing casting systems can be retrofitted for the new method with relatively-little expense.
BRIEF DESCRIPTION OF THE DRAWINGS
One exemplary embodiment of the invention will be described in greater detail hereinafter in connection with the drawings, in which:
FIG. 1
is a side view of a casting system of the invention, partially in cross section,
FIG. 2
is a top view of the casting system according to
FIG. 1
,
FIG. 3
illustrates the casting system illustrated in
FIG. 1
during the mold filling,
FIG. 4
is a top view of the casting system according to
FIG. 3
,
FIGS. 5 and 6
illustrate the casting system according to the invention corresponding to
FIGS. 3 and 4
, however, with the mold being inclined with respect to the horizontal during casting.
DETAILED DESCRIPTION
Reference numeral
1
in the drawings identifies a floor-mounted .conveyor on which the casting boxes
2
are transported by means of a transport carriage
3
′. The transport carriage
3
moves with its wheels
3
on rails
4
, a section of the rails
4
is arranged on a moving carriage.
5
, which in turn has wheels
6
which run on rails
7
extending transversely with respect to the rails
4
of the floor-mounted conveyor
1
. The moving carriage
5
is driven by a double-acting piston-cylinder unit
8
.
The casting box
2
consists of an upper box
9
and a lower box
10
, which together receive the mold
11
. The mold-dividing plane
12
is aligned horizontally in the exemplary embodiment according to FIG.
1
. The illustrated mold
11
is a clay-bound sand mold having a mold cavity
13
, connected to an intake channel
14
, which ends in the mold-dividing plane
12
. The upper and lower boxes
9
,
10
have for this purpose a recess
15
which is designed conically and defines a bearing surface
16
surrounding the opening
17
of the intake channel
14
.
A filter
18
is inserted into the intake channel
14
just before its end, which filter prevent's sand particles of the mold from exiting through the opening
17
of the intake channel
14
.
A channel
19
is formed into the upper half of the mold
11
, which channel ends a short distance from the intake channel
14
. A ram
20
of a blocking cylinder
21
can be introduced into this channel, which ram moves the sand between the end of the channel
19
and the intake channel
14
in such a manner that said sand closes off the intake channel
14
.
Reference numeral
22
identifies a casting machine which has a pressure kettle
23
closed off with a lid
24
. The lid has a pressure-gas connection
25
, through which pressurized gas can be introduced into the space above the bath level
26
of the molten metal
27
.
The pressure kettle is connected at, one side of the lower area to a fill pipeline
28
and at the other side to a fill chute
29
. The fill chute
29
terminates in a fill funnel
30
, the opening of which ends both above the pressure kettle
23
and also above the port
31
of the fill pipeline
28
. The fill pipeline
28
is essentially horizontally designed in its upper part and ends here in a head channel
32
which is closed off on all sides. The head channel can have a closable opening in order to be able to clean same better when needed.
The casting machine
22
has an induction heating system
33
, with which the melt
27
is maintained at the casting temperature. The casting machine
22
has wheels
34
which run on rails
35
so that the casting machine can, if necessary, also be moved to a refill oven. On the other hand, it is also possible to fill the casting machine on site with the help of a pan.
The casting system of the invention operates as follows:
The molds are supplied together with their casting boxes on the floor-mounted conveyor in direction of the arrow
37
(
FIG. 2
) and move in cycles with their transport carriage
3
onto the moving carriage
5
. The moving carriage
5
. is then moved by means of the piston-cylinder unit
8
in direction of the arrow
39
until the port
31
of the fill pipeline
28
rests on the bearing surface
16
of the mold
11
. The piston-cylinder unit
8
is thereby loaded with such a pressure that a specified bearing pressure between the port
31
and the bearing surface
16
occurs. Pressurized gas is thereafter blown through the pressure-gas connection
25
into the pressure kettle
23
until the level of the molten metal in the fill pipeline
28
runs through the port
31
into the intake channel
14
of the mold
11
. The pressure is hereafter still further increased until the specified fill pressure for the mold
11
is obtained. This pressure is maintained over the entire fill-time of the mold cavity
13
of the mold
11
, whereby it is also possible to provide a specific pressure profile in dependency of the mold cavity
13
.
In the here illustrated embodiment of the mold
11
, same has a vent channel
40
, through which the gas contained in the mold cavity can escape. However, this vent channel is not absolutely necessary and it can be deleted when the mold as such is sufficiently gaspermeable for the filling process. This has the advantage that on the one hand subsequent work to remove the metal accumulating in the vent channel is not needed and on the other hand also the material cycle is further reduced.
After the mold has been filled, the ram
20
is moved into the channel
19
by means of the blocking cylinder
21
, whereby the sand is hereby shifted in such a manner that sand closes off the intake channel
14
. After the ram
20
has been moved out of the channel
19
, the casting box with the mold
11
can be moved back directly into its initial position so that via a cyclical operation a further casting box with a new mold
11
can be positioned on the moving carriage
5
. The described casting operation is then repeated.
FIG. 3
illustrates the aforedescribed filling process and the casting box with the mold
11
moved into the filling position.
FIG. 3
shows how the increased pressure acts in the pressure kettle
23
, whereby said pressure can be increased to the level permitted by the fill funnel
30
of the fill-chute
29
. The exemplary embodiment illustrated in
FIGS. 5 and 6
differs from the one in the preceding figure merely in the mold
11
including the casting box
2
, the transport carriage
3
and the moving carriage
5
having been tilted at an angle α with respect to the horizontal. This also assumes that the head channel
32
of the fill pipeline
28
is designed correspondingly inclined so that the port
31
of the fill pipeline
28
securely abuts the bearing surface
16
of the intake channel
14
. This inclined arrangement of the casting box
2
and of the mold
11
can be advantageous for filling of molds with complicated mold cavities
13
.
FIG. 6
illustrates the casting box
2
with the mold
11
, which casting box is in comparison to
FIG. 5
moved toward the casting machine
22
, and the bath level within the casting machine
22
having been lowered by the amount required to fill the mold.
Claims
- 1. A casting system comprising at least one mold consisting of lower and upper parts each having an internal mold cavity separated by a generally horizontally oriented mold-dividing plane and an intake channel extending in and along the mold-dividing plane to provide a generally horizontally facing inlet port to the mold cavity, wherein the casting system additionally includes a casting machine having a generally horizontally facing outlet port through which molten metal flows for facilitating a filling of the mold cavity and a transport device for supplying and removing the molds and the inlet thereof in a transport direction to and from a position adjacent the casting machine and the outlet thereof, and a blocking device for blocking the intake channels to the mold cavities after the filling of molten metal has occurred, wherein the transport device includes a movable carriage and a guide track therefor, by means of which the mold and the inlet port thereof are moved transversely with respect to the transport direction toward and away from a coupled relation to the outlet port of the casting machine, whereby the inlet port to mold is moved into a coupled relation with the outlet-port of the casting machine, and wherein the casting machine includes a pressure port for facilitating a pressurization of an interior thereof for pressing by means of overpressure in the casting machine molten metal through the outlet port into the inlet port and thence into the mold cavity of the mold.
- 2. The casting system according to claim 1, wherein the casting machine has a pressure kettle receiving the metal to be cast, into the lower area of which pressure kettle terminates lower ends of a fill chute and a fill pipeline coupled at an upper end thereof to the horizontally facing outlet port, and wherein the fill chute has a fill funnel which projects above the fill level of the pressure kettle and the outlet port.
- 3. The casting system according to claim 2, wherein the pressure port is provided on the pressure kettle and includes a pressurized gas connection.
- 4. The casting system according to claim 1, wherein the casting machine has several fill pipelines.
- 5. The casting system according to claim 1, wherein the casting machine is movable arranged.
- 6. The casting system according to claim 1, wherein the casting machine has a heating system.
- 7. The casting system according to claim 1, wherein the inlet port includes a conically-shaped recess.
- 8. The casting system according to claim 1, wherein the mold consists of mold sand and wherein in the mold sand of the mold there is provided a channel extending from an outer surface of the mold sand to a location adjacent the intake channel, the blocking device including a blocking cylinder and an extendible and retractable ram, the ram being coaxially aligned with the channel as well as receivable therein to effect a movement of mold sand into the intake channel to close off the connection between the intake channel and the outlet port following a filling of molten metal into the mold cavity.
- 9. The casting system according to claim 8, wherein the mold sand has such a gas permeability that the mold cavity, with the exception of the intake channel, is designed closed.
- 10. The casting system according to claim 1, wherein a filter is built into the intake channel.
Priority Claims (1)
Number |
Date |
Country |
Kind |
199 20 267 |
May 1999 |
DE |
|
US Referenced Citations (10)
Foreign Referenced Citations (7)
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Country |
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Jun 1932 |
DE |
1 758 634 |
Sep 1970 |
DE |
26 52 657 |
Jun 1977 |
DE |
42 04 262 |
Aug 1993 |
DE |
198 34 553 |
Feb 2000 |
DE |
0 894 557 |
Feb 1999 |
EP |
2268959 |
Feb 1990 |
JP |