DE1060106B - Sand blowing machine for the production of cores, molded masks and the like Like. For foundry purposes - Google Patents

Description

GERMAN

The invention relates to a sandblowing machine which is used for the production of cores, molded masks and the like for To serve foundry purposes. Devices are already known with which the molding compound for cores, Form masks and forms under compressed air in the core box or forms is blown or inflated. Such blow molding machines have been developed especially for the production of cores, with relatively high pressures have already been used, so that one can avoid shooting in the Molding compound speaks into the core box. In principle, these facilities consist of: one Container or boiler in which the sand and a synthetic binder, for example synthetic resin, mixed mass is located. A pipe protruding into the mass leads to the blow point on which the Core box is sealingly placed, and another tube protrudes into the container so that it ends above the mass poured into the container. This line becomes the container put under pressure, the mass is conveyed through the other pipe to the blowing point.

Devices have also become known in which the sand filling is in a container, which is arranged above the core to be produced is located. Thereby the sand filling separated from the opening of the air inlet pipe by a sieve plate or a porous cylinder. When the compressed air is introduced, it flows through the sieve plate or the porous cylinder and drives the sand out of the container.

Another proposal for the production of cores is a certain amount of sand from a punch out larger sand supply and as a whole by means of a hollow punch through an opening in the container wall to push through into the molding box. Finally there was a core and blow molding machine known, in which the blown air is used at the same time to loosen the sand and the lower part of the Sand container is supplied.

All of these arrangements have certain disadvantages. First there is the risk that the compressed air flow, which is introduced into the container, whirls up the mass, so that unintentionally a kind of wind sifting occurs, wherein in particular the synthetic resin is whirled up from the mass. As a result, you can produce slightly uneven products if care is not taken to keep the mass constant stirred and mixed again in this way. The required amount of compressed air can do not dose exactly, it must therefore be worked with an excess of compressed air, which is purely in terms of energy seen means a loss. In addition, the blowing process takes a long time, even if

for the production of cores,

Molded masks and the like for foundry purposes

Applicant:

German stainless steel works

Corporation,
Krefeld, Oberschlesienstr. 16

Dipl.-Ing. Dr. Franz Pölzguter, Bochum,

Walter Pöhlandt, Mannheim-Rheinau,

and Kurt Linneweh, Mannheim-Neckarau,

have been named as inventors

moderate high pressures are used for a considerable time.

These disadvantages are to be eliminated according to the invention. In particular, a device be created that a sudden promotion of the mass, the sand or the like. From the. pressure vessel zur BlasstJle without the risk of segregation. Furthermore, the device should additionally also be constructed so that a dosage of the amount of compressed air using the simplest control means is possible.

To solve this problem, according to the invention, a machine for shooting cores, molded masks and the like for foundry purposes is proposed, which consists of a container for receiving the material for the production of the cores or molds, in which a compressed air supply pipe is installed. Further, a projecting into said mass second tube is provided, which is guided outwardly to the filling station _R to which the core or mold box is sealingly mounted in such a way that the mass is shot from its container upon actuation of a valve in the compressed air supply line. The device is characterized in that in the container the compressed air flowing upwards from the Druclduftzuleitangsrohr is directed to a concave baffle plate arranged above the mass, which is designed at the same time with its rear concave surface as a closure for the filling. This ensures that the pressure of the compressed air flowing out of the compressed air supply line creates a directed jet in the

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Container generated, whereby the vortex otherwise possible in this container is suppressed. Of the Pressure therefore acts on its surface without whirling up the mass and thus drives the mass out of it Blowpipe off. This facility already ensures a flawless shot-like conveyance of the goods Guaranteed from the shot pot to the blow point. The shot or sudden effect is intensified, in that this "shot chamber" is preceded by a permanently pressurized shot cylinder with "piston" is, from which compressed air is suddenly supplied to the shot tank by the sudden release of the supply lines will. The piston, which is provided with a relief valve, can be used to dose the amount to be ejected The amount of compressed air can be adjusted to different starting positions. The adjustable Stops for limiting the piston stroke are expediently resilient, preferably off Rubber, trained. A tensioning device can also be provided for tensioning the core box, in the clamping plates of which ventilation nozzles are attached. So it is not only achieved that the compressed air fed to the shot chamber under high pressure and while maintaining the selected pressure level constant but also in a precisely dosed amount. This saves compressed air and reduces the blowing time to an absolutely necessary minimum.

Since the control device for such a task is relatively simple despite the good effect and is small, there is the possibility of having the entire system in a closed machine table to unite on the. only the blow point with the clamping devices is at the top.

In the drawings is a preferred embodiment of the inventive concept in a schematic section (Fig. 1), in a section through the hemispherical plate (Fig. 2) and shown in an overall side view (Fig. 3). On the basis of this Drawings the invention is explained in more detail below, and there are further features of the invention, shown.

In the schematic Fig. 1 is above the table top edge 1 of the self-contained table 100 the blowing point 2, which is designed as a core blowing point in the example chosen. Below the top of the table and thus within the closed table are the container 3 and the shot cylinder 4th

In the container 3, the mass of sand or a sand synthetic resin mixture is indicated at 3a. Of the Container leads a pipe 5 protruding into the mass 3 a to the blowing point 2. A compressed air supply line 6 is introduced from below into the container 3 and is on a hemispherical baffle plate 7, which is on the lid of the container 3 is arranged, directed.

This hemispherical baffle plate 7 on which the pipe 6 is directed, has the purpose of the entering Divert compressed air flow so that it is like a hood or a bell on the surface of the filled mass 3 ο presses and drives it through the tube 5 in a shot. As a result of this diversion of the sudden incoming compressed air is any whirling up of the mass 3 ο prevented, regardless of whether it is in dry, free-flowing or even in a moist state, and it also becomes a completely even pressure effect achieved. A segregation of even completely dry Alassen, which also are also mixed together from substances that have different specific gravity is on prevented this way. 'Conveniently, the hemispherical Impact plate 7 perform a double function, namely by opening and closing at the same time the filling opening 8 is used. A funnel 9, which is attached to the upper edge of the table 1, leads to the filling opening 8 a sieve 10 is covered. The required amount of mass 3 α is passed through this sieve into the container 3 Poured in, and in addition, the excess mass when blowing is through the sieve · 10 into the container 3 poured back. The hemispherical baffle 7 and its additional facilities are can be seen more clearly from Fig. 2. At the filling opening 8, a seal 11 is provided against which the baffle plate 7 rests in a sealing manner in the closed position. Through the guide 12, which is under spring pressure stands, the plate 7 is pressed down, so that the opening 8 for filling. Mass is free. A spring 13 supported on the baffle plate 7 presses the closure 14 for the tube 6 down. on This way it is prevented that when filling the mass or with constant back pouring after each Blowing process parts of the mass get into the tube 6. If the tube 6 is pressurized, it lifts the closure 14 presses on the spring 13, the hemispherical baffle plate 7 against the seal 11, and the immediately following flow of compressed air increases the seal pressure.

Although the device already described in connection with the container 3 and the baffle plate 7 is fully effective when the container 3 is acted upon directly from the compressed air network, it is according to of the invention particularly advantageous with abrupt To work the supply of dosed amounts of compressed air, for this purpose the shot cylinder 4 is arranged upstream of the container, from which the line 6 leads to the container 3.

The shot cylinder 4 is closed on all sides. In the interior there is a. Piston 15, which is double-acting and has two Dichtungsoianschetten. To the space above the piston ¹ performs the line 16, which are connected to the Preßluftnetz 19 via a three-way valve 18 to the space below the line 17th

The piston is equipped with rubber buffers 20, which interact with rubber stops 21 and 22, which limit the end movement of the piston. The lower stop 22 is a certain amount height adjustable. The piston itself cannot go through in detail with regard to its starting position Means shown are set so that there is a certain volume of air below the piston is included. This volume of air has the pressure of the compressed air network. The pressure can form because there is a three-way valve 23 in the line 6, which connects the line to the container 3 concludes.

A relief valve is also located in the piston 15 24.

The mode of operation of the upstream shot cylinder 4 with its facilities is the following:

The three-way valve 23 and the three-way valve 18 are coupled to one another in such a way that when the valve is closed Three-way valve 23 through the three-way valve 18, the supply line 17 to the space below the piston 15 is released The pressure lifts the piston. 15 to in the set starting position, and there is now a very specific amount of air required for blowing included below the piston. If it is now to be blown, the three-way valve 23 is opened and at the same time the Draiwegehahn 18 changed over in such a way that that the line 17 completed "and the

Claims (4)

Line 16 is released. As a result, the amount of air located below the piston is suddenly relieved to the container 3 and drives the mass to the blow point, in that the piston 15, which is under the pressure of the compressed air network, expresses the volume of air in the direction of the container 3. Depending on the circumstances, pressures of up to 6 atmospheres can be used in this way, preferably 3 atmospheres are used. The high pressure, combined with the sudden pressure effect, allows the production of particularly dense cores, molded masks and the like the piston 15 automatically rises to its starting position. The pressure relief required for this from the top of the piston to the bottom of the piston takes place via the relief valve 24. Since the "device according to the invention works with high suddenly acting pressures, particular care must be taken to ensure that the air trapped in the model or in the core box at the blow or shot point 2 In the exemplary embodiment (Fig. 1) a clamping point 2 for core boxes is shown. The core boxes or core boxes are clamped between the fixed clamping plate 25, in which the feed 5 ends, and the movable clamping plate 26. The clamping plate 26 can be fitted with compressed air operated clamping cylinder 27. Up to now it has generally been customary to provide a core box with air nozzles in order to allow the trapped air to escape when the mass is pushed in. The core boxes are at a relatively high temperature so that those made of sand and synthetic resin or the like existing mass with melting of the synthetic resin to the Baked walls to achieve the core shape. However, the air nozzles on such a core box clog, especially when working with high and sudden pressures, because the mass in them also settles and cakes. To avoid this, the core boxes according to the invention are not provided with air nozzles, they will. 4-5 rather in the cold ones. Laying chipboards. It is particularly expedient to provide the fixed clamping plate 25, which at the same time carries the feed 5, with vent nozzles 29, 30 so that the enclosed air is expelled backwards by the injecting mass. The blowing process takes only a fraction of a second and, thanks to the adjustability of the required air volume, takes place without any loss of compressed air. The excess of non-caking mass is also kept within narrow limits. The worker takes the blown core box out of the clamping device and pours the small amount of excess mass through the sieve 10 into the funnel 9, from where it returns to the container 3. A vibrator 28 can be provided on the funnel 9 in order to ensure that the mass flows off in a controlled manner through the funnel. Patent claims: 1. Machine for shooting cores., Form masks and the like. For foundry purposes with a Container to hold the mass for the production of the cores or forms, in the one Compressed air supply pipe is installed, with a second pipe protruding into the mass after is led outside to the filling point on which the core or molding box is sealingly attached, such that when a valve is operated in the compressed air supply line, the mass from its container is shot, characterized in that in the container (3) the upward from the compressed air supply pipe (16) escaping compressed air onto a concave baffle plate arranged above the mass (7) is directed at the same time with its rear concave surface as a closure for the product filling opening is formed 2. Machine according to claim 1, characterized in that the material container (3) a constantly pressurized shot cylinder (4) with piston (15) is arranged upstream from which by sudden Release of the supply lines compressed air can be suddenly fed to the material container. 3. Machine according to claim 1, characterized in that the one with a relief valve (24) provided piston (15) for metering the amount of compressed air to be ejected to different levels Starting positions is adjustable, the adjustable stops (21, 22) to limit the Piston stroke are resilient, preferably made of rubber. 4. Machine according to claim 1, characterized in that for tensioning the core box a Clamping device (25, 26, 27) is provided, in the clamping plates of which ventilation nozzles (29, 30) are attached are. Considered publications:
German patent application K 12520VIa / 31b (published on 25.9.1952); German Patent Nos. 839 247, 524373;
British Patent Nos. 672 487, 601 714. 1 sheet of drawings © 909 558/106 6.