DEVICE FOR LOW-PRESSURE CASTING OF WORKPIECES WITH A SWIVEL COUPLING

Description

[0001] The present invention relates to a device for low-pressure casting of workpieces. The device allows a molten metal to be conveyed into a mold cavity of a mounted casting mold via a riser pipe.

[0002] In low-pressure casting, the (gas) pressure in a melting pot is increased by introducing a gas. This forces the molten metal vertically upward through a riser tube into the mold cavity, against the force of gravity. While the molten metal is being poured into the mold cavity, the mold cannot be moved on the fixture. This can lead to uneven filling of the mold cavity or defects such as blowholes and gas pores in the finished workpieces.

[0003] US 3 054 155 A, US 3 329 201 A, US 2 852 822 A, and GB 855 673 A disclose devices for casting workpieces in which a casting mold is attached at an angle to a melting crucible. Furthermore, EP 0 714 718 A1 discloses a device for casting workpieces in which a casting mold is arranged on a frame on a melting crucible. DE 199 63 216 A1 discloses a casting device with a melting crucible and a riser pipe. For cleaning the melt or changing the melting crucible, a furnace plate can be pivoted together with a casting mold.

[0004] The object of the invention is therefore to at least partially solve the problems described with reference to the prior art and, in particular, to provide a device for low-pressure casting of workpieces with which defective workpieces can be avoided.

[0005] This object is achieved with a device according to the features of the independent patent claim. Further advantageous embodiments of the invention are specified in the dependent patent claims. It should be noted that the features listed individually in the dependent patent claims can be combined with one another in any technologically expedient manner and define further embodiments of the invention. Furthermore, the features listed in the patent claims are further specified and explained in the description, with further preferred embodiments of the invention being presented.

[0006] A device for low-pressure casting of workpieces contributes to this, which has at least the following components: a) a melting crucible for holding a molten metal, b) a riser pipe by means of which the molten metal can be fed from the melting crucible to a casting mould, and c) a coupling by means of which the casting mould can be pivotally connected to the device so that the molten metal can be fed to the casting mould while the casting mould is pivoting.

[0007] The device is used for the low-pressure casting of workpieces, which can be, for example, fitting bodies or fitting housings for sanitary fittings. Sanitary fittings are used in particular for the demand-based provision of liquids, such as water, to sinks, wash basins, showers and / or bathtubs. For this purpose, the sanitary fitting can be supplied with cold water at a cold water temperature and hot water at a hot water temperature. The cold water and hot water can be mixed by the sanitary fitting, in particular by means of a mixing valve or a (thermostat) mixing cartridge, for example, to form mixed water with a desired mixed water temperature. The cold water temperature is in particular a maximum of 25 °C (Celsius), preferably 1 °C to 25 °C, particularly preferably 5 °C to 20 °C and / or the hot water temperature is in particular a maximum of 90 °C, preferably 25 °C to 90 °C, particularly preferably 55 °C to 65 °C.The mixing valve or (thermostatic) mixing cartridge can be located in the body or housing of the sanitary fitting. The body or housing can be attached to a support, such as a countertop, sink, washbasin, bathtub, or shower.

[0008] The device comprises a melting crucible for holding a molten metal. The holding space of the melting crucible for the molten metal can, for example, have a holding volume of 0.001 m³ (cubic meter) to 1 m³. The device can comprise a melting furnace and / or holding furnace by means of which a metal or a metal alloy can be melted in the melting crucible and / or kept hot above a melting temperature. The metal can, for example, be copper, brass, aluminum, magnesium, iron and / or steel. For this purpose, the melting crucible can be made at least partially of a refractory material that can withstand temperatures of the molten metal of, for example, up to 1,500°C.

[0009] The device has a riser pipe, the lower longitudinal end of which projects below a liquid level of the molten metal into the receiving space of the melting crucible during operation of the device. The riser pipe is made at least partially of a material that can withstand temperatures of the molten metal, for example up to 1,500 °C. During low-pressure casting, the molten metal is pressed from below through the riser pipe into a mold cavity of a mounted casting mold. The upward movement of the molten metal is achieved according to the gas pressure principle, i.e. an excess pressure acts on the bath surface of the molten metal, which forces the molten metal against gravity through the riser pipe into the mold cavity of the casting mold. This can occur by pressurizing the molten metal in the crucible or by negative pressure in the mold cavity of the casting mold.The overpressure in the receiving space of the crucible can be, for example, 0.5 bar to 3 bar and / or can be generated by introducing a gas, such as (ambient) air, into the receiving space of the crucible. The crucible can be arranged in a (gas-tight) container into which the gas can be introduced. The container can be closed (gas-tight) by a lid. The casting mold is, in particular, a permanent mold, for example in the manner of a permanent mold. The casting mold is, in particular, made at least partially of metal. In low-pressure casting, the casting mold is placed on the device or the lid of the device so that the melt can flow from the crucible via the riser pipe into the mold cavity of the casting mold. In low-pressure casting, the device and the casting mold thus form a unit that is connected by the riser pipe.

[0010] The device also has a coupling via which the casting mold can be pivotally connected to the device. For this purpose, the casting mold can be placed on the coupling. The coupling can be pivoted or moved by the casting mold. Furthermore, the coupling enables the casting mold to be pivoted or moved relative to the device while maintaining the connection between the riser pipe and the casting mold. The coupling can be cardanically mounted on the device or the cover of the device. The coupling allows the molten metal to be fed into the casting mold even when the casting mold is pivoted. This can prevent defects such as blowholes and / or gas pores in the finished workpieces.

[0011] The casting mold can be pivotally connected to the device via the coupling about at least two axes. These two axes can be, for example, an x-axis and a y-axis, which can run orthogonally to each other and horizontally. Additionally, the casting mold can be pivotally connected to the device via the coupling about a further or third axis. The third axis can be a z-axis, which runs vertically and / or orthogonally to the x-axis and y-axis. This allows the casting mold to be pivoted or rotated in all directions relative to the device during low-pressure casting.

[0012] The coupling is arranged at a longitudinal end of the riser pipe. In particular, the coupling is arranged at the longitudinal end of the riser pipe opposite the longitudinal end of the riser pipe with which the riser pipe extends into the molten metal.

[0013] The molten metal can be guided through the coupling. This means that the molten metal flows through the coupling during low-pressure casting.

[0014] The coupling can be designed at least partially in the form of a spherical segment. In the area of ​​the spherical segment, the coupling particularly has at least partially a spherical, dome-shaped, or spherical surface.

[0015] The coupling is pivotally mounted in a bearing cup. The bearing cup serves to accommodate the coupling. Furthermore, the bearing cup can be designed, in particular, at least partially, in the manner of a ball and socket. In particular, a spherical segment-shaped region of the coupling is pivotally movable (in all directions) in the bearing cup. The coupling contacts the bearing cup, in particular with its spherical, dome-shaped, or spherical surface. The bearing cup is formed, in particular, on the device, on a cover of the device, or on a cover of a container of the melting pot. When the casting mold is pivoted, the coupling slides in the bearing cup.

[0016] The coupling can be pivoted relative to the riser pipe. This can mean that the riser pipe is not attached to the coupling. In this case, the riser pipe can be attached, in particular, to the device, a lid of the device, or a lid of a container for the melting pot. Thus, the riser pipe is not movable relative to the device. The coupling can be firmly connected to the riser pipe, so that the riser pipe can be moved with the coupling. When the coupling is pivoted, the riser pipe is thus moved along in the melting pot. It must be ensured that the lower, longitudinal end of the pipe is always below the liquid level of the molten metal.

[0017] The riser pipe has a first melt channel that opens into a second melt channel of the coupling. The first melt channel extends in particular from the first longitudinal end to the second longitudinal end of the riser pipe. The second melt channel extends in particular through a center of the coupling.

[0018] The first melt channel can have a first diameter that is larger than a second diameter of the second melt channel. This ensures that the cross-section of the second melt channel is not reduced when the coupling is pivoted.

[0019] With the solution outlined here, significant quality improvements can be observed with regard to process control and the casting result, such as improved material flow in the mold, the reduction / avoidance of air inclusions or cavities in the material, and particularly low porosity of the material.

[0020] Furthermore, it is possible to divert any gas surge that may occur as a result of an (undesired) quartz jump.

[0021] The feeder system is designed to be significantly simplified because the clever filling allows for a precise final feeding point, whereby closed feeders may even be dispensed with.

[0022] In addition, the invention allows the mold to be guided by or with a robot.

[0023] The invention and the technical environment are explained in more detail below with reference to the figures. It should be noted that the figures show particularly preferred embodiments of the invention, but the invention is not limited thereto. Identical components in the figures are provided with the same reference numerals. They show, by way of example and schematically: Fig. 1: a first embodiment of a device for low-pressure casting of workpieces; and Fig. 2: a second embodiment of the device for low-pressure casting of workpieces.

[0024] The Fig. 1It shows a first embodiment of a device 1 for low-pressure casting of workpieces. The device 1 comprises a melting pot 2 for a molten metal 3. The melting pot 2 can be heated by a melting furnace or holding furnace (not shown here) in order to melt metals in the melting pot 2 into the molten metal 3 or to keep the molten metal 3 warm. Furthermore, the melting pot 2 is located in a container 17, which is hermetically sealed by a lid 18. At the beginning of a casting process, a gas 19 is fed into the container 17, whereby the pressure in the container 17 increases. As a result, the molten metal 3 flows through a riser pipe 4 and a melt inlet 21 of a casting mold 5 into a mold cavity 20 of the casting mold 5. The casting mold 5 is designed in the manner of a chill mold and can have outlets (not shown here) through which air can escape from the mold cavity 20 as the molten metal 3 flows in.Furthermore, the casting mold 5 is placed on a coupling 6 of the device 1, so that the melt inlet 21 is tightly connected to the riser pipe 4. The coupling 6 is designed in the manner of a spherical segment 11 and mounted in a bearing socket 12 of the lid 18. As a result, the coupling 6 can be pivoted or rotated with the casting mold 5 about an x-axis 7 (perpendicular to the plane of the drawing), a y-axis 8, and a z-axis 9. In the first embodiment of the device 1 shown here, the coupling 6 is firmly connected to the riser pipe 4 at a longitudinal end 10 of the riser pipe 4. When the casting mold 5 or the coupling 6 is pivoted, the riser pipe 4 is therefore also pivoted. In addition, a spring 22 is arranged between the container 17 and the lid 18, which spring presses the lid 18 with the coupling 6 against the casting mold 5. This ensures that the riser pipe 4 is tightly connected to the melt inlet 21 of the casting mold 5.

[0025] The Fig. 2shows a second embodiment of the device 1. The second embodiment of the device 1 differs from that shown in the Fig. 1 shown first embodiment of the device 1 only in that the riser pipe 4 is not firmly connected to the coupling 6, but rather to the cover 18. The coupling 6 and the casting mold 5 can therefore be pivoted about the x-axis 7, y-axis 8 and the z-axis 9 in the bearing pan 12 of the cover 18 without the riser pipe 4. The riser pipe 4 here has a first melt channel 13 with a first diameter 15 and the coupling 6 has a second melt channel 14 with a second diameter 16. The first diameter 15 is larger than the second diameter 16, so that the second melt channel 14 is completely open when the coupling 6 is pivoted.

[0026] The present invention enables workpieces to be produced by low-pressure casting without defects such as cavities or gas pores. List of reference symbols

[0027] 1Device 2Melting crucible 3Molten metal 4Riser tube 5Mould 6Coupling 7x-axis 8y-axis 9z-axis 10Longitudinal end 11Spherical segment 12Bearing pan 13First melt channel 14Second melt channel 15First diameter 16Second diameter 17Vessel 18Lid 19Gas 20Mould cavity 21Melt inlet 22Spring

Claims

1. A device (1) for low pressure casting of workpieces, comprising: a) a melting crucible (2) for receiving a molten metal (3), b) a riser pipe (4) with which the molten metal (3) can be fed from the melting crucible (2) to a casting mold (5), and c) a coupling (6) via which the casting mold (5) can be pivotably connected to the device (1) so that the molten metal (3) can be fed to the casting mold (5) during the pivoting of the casting mold (5), wherein the coupling (6) is connected to a longitudinal end (10) of the riser pipe (4), wherein the molten metal (3) can be guided through the coupling (6), wherein the riser pipe (4) has a first melt channel (13) which opens into a second melt channel (14) of the coupling (6), characterized in that the coupling (6) is pivotably mounted in a bearing cup (12).

2. The device (1) according to claim 1, wherein the casting mold (5) can be connected to the device (1) via the coupling (6) to be pivotable about at least two axes (7, 8, 9).

3. The device (1) according to any one of the preceding claims, wherein the coupling (6) is at least partially designed in the form of a spherical segment (11).

4. The device (1) according to any one of the preceding claims, wherein the coupling (6) is pivotable with respect to the riser pipe (4).

5. The device (1) according to any one of claims 1 to 3, wherein the coupling (6) is firmly connected to the riser pipe (4), so that the riser pipe (4) can be moved with the coupling (6).

6. The device (1) according to any one of the preceding claims, wherein the first melt channel (13) has a first diameter (15) which is larger than a second diameter (16) of the second melt channel (14).