SU1726120A1 - Casting knock-out method and knock-out device - Google Patents

Abstract

The invention relates to foundry and can be used for knocking out casting molds. The method includes the combined discharge of compressed air from the supravalvular and central cavities 13 /

Description

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working cavity with a pulse effect on the molding mixture, in relation to which the impulse of compressed air from the extreme working cavities is delayed by 0.1-0.2 s. The device comprises a housing 1 with a central 2 and an extreme 3 working cavities, in which respectively a central 4 and an extreme 5 valves are installed, blocking the central 6 and the extreme exhaust ports. 8 extreme pistons

The invention relates to foundry and relates to a technology and equipment for the ejection of an air pressure pulse by casting molds.

There is a known method of knocking out castings from a mold, which includes a pulse of air pressure on the surface of the mold and the subsequent side blowing of the molding sand with compressed air.

To implement this method, a device is known comprising a housing with a valve and a working cavity, in the lower part of which a fixed perforated plate with blower valves is fixed.

A disadvantage of the proposed method and device is the impossibility of their use for knocking out a ring-shaped profile from a casting mold, since the cooling valves are installed in a fixed perforated plate without the possibility of adjustment and are always directed to the center of the casting.

No less significant disadvantage of the known method and device is the waste of compressed air. On the one hand, they are caused by a decrease in the pressure of compressed air in the gap that exists between the lower end of the fixed perforated plate and the surface of the mold. On the other hand, they are a consequence of the supply of compressed air through the blower valves.

Closest to the present invention is a method of knocking out castings from a mold, including an impulse of air pressure on the surface of the mold.

To implement this method, a device is known comprising a housing with a flange and a working chamber with a central valve installed in it, which is permanently attached to the beam.

The use of this method and device is also associated with unproductive losses of compressed air, since

the valves 5 are installed in the housing 1, the piston 9 of the central valve A is installed in the flange 10 located with gaps 11 relative to the extreme valves 5. The height of the gaps 11 is commensurate with the height of the above-cavity cavities 12 extreme valves 5, which communicate with each other and with the working cavity 2 central valve 4. The central valve 4 is pressed against the spring 13, abutting against the cover 14. 2 sp. f-ly, 3 ill.

There is a zone in the central valve that does not absorb the direct impulse air pressure flows. Because of such losses, it is necessary to increase in the working chamber

compressed air charge.

The second drawback is related to the fact that when knocking out castings from large casting molds, it is necessary to accumulate a significant charge in the working chamber.

air, with the release of which creates an air pressure pulse, brief in time, but creating a very large impact force, which is unconditionally transmitted by the snap-in snap and leads to the intersection of the cross or the formation of cracks in the structural elements of the flask.

The purpose of the invention is to reduce the unproductive losses of compressed air and increase the service life of the rivet equipment.

This goal is achieved by the fact that in the method of knocking out castings from a mold, mainly ring-shaped, including the supply of an air pressure pulse

on the surface of the mold, an impulse of air pressure is carried out successively in the center and periphery, and a pressure impulse in the center is combined with the discharge of compressed air from the above-valve cavities. Wherein

the pressure pulse in the periphery is delayed by 0.1-0.2 s relative to the pressure pulse in the center.

This goal is also achieved by the fact that in a device for knocking out castings from a mold, mainly ring-shaped, containing a housing with a flange and a working chamber with a central valve installed in it, central and peripheral cavities with valves and valve flaps of peripheral valves are made in the working chamber and the central cavity communicates with each other, and the piston of the central valve is located in the flange,

located with a gap relative to the peripheral valves.

Due to the discharge of compressed air from the supravalve cavities in the combined flow with the impulse of compressed air from the central cavity and the constructive embodiment of which. that the over-valve cavities of the peripheral valves communicate with each other and with the working central cavity, a reduction in the unproductive losses of compressed air is achieved, since there are no zones underneath the central or the peripheral valves that do not perceive direct air flow pulses. There are only direct streams that are completely directed to the performance of a useful rig.

Due to the fact that the impulse of air pressure from the peripheral cavities is delayed with respect to the compressed air impulse from the central cavity by 0.1-0.2 s, and the piston of the central valve is installed in the flange located with a gap relative to the peripheral valves, an extended The impulse of compressed air, the first part of which is aimed at the destruction of the molding mixture inside the casting, and the second along its perimeter. This reduces the impact of the casting on the tooling and increases its service life.

A time delay of less than 0.1 s is not recommended, since in this case both parts of the pulse are merged into one, creating such a large force that can lead to premature release of the snap-on tool.

A time delay of more than 0.2 s suppresses performance and is impractical due to a decrease in pressure in the tooling after the first part of the pulse. A significant decrease in pressure leads to the fact that the second part of the pulsed charge follows the path made by charging the compressed air pulse from the central working cavity with minimal useful work.

1 shows a device for knocking out castings from a mold in the initial position, a general view; Figure 2 is the same after the central valve is triggered; fig. 3 - the same, after the operation of the central and peripheral valves.

The device comprises a housing 1 with a working chamber, in which central 2 and peripheral 3 cavities are made, and central 4 and peripheral 5 valves are installed in them, overlapping the central 6 and peripheral 7 exhaust ports. The pistons 8 of the peripheral valves 5 are installed in the housing 1, and the piston 9 of the central valve 4 is installed in a flange 10 located with a gap 11 relative to the peripheral valves 5. The height of the gap 11 is practically commensurate with the height of the valve valve 12, the peripheral valves 5, which

5 communicated with each other and with the central cavity 2 ..

The central valve 4 is pressed against the central exhaust opening 6 by a spring 13, abutting against the cover 14, which is formed with the opening 15.

A radial orifice 17 is made in the control cavity 16 in the flange 10 to supply compressed air.

To supply compressed air to the central cavity 2 and the valve chamber 12, an opening 18 is made in the housing 1.

To supply compressed air into the peripheral cavities 3 in the housing, holes 19 are made.

0 Foundry form contains the top 20

and bottom 21 flasks, the last of which

performed with a crosspiece 22. Flasks 20 and 21

filled with molding mixture 23. in which the casting 24 of ring-shaped is placed

5 profiles

The proposed method of knocking out castings from a casting mold is carried out with the following sequence of operations. Through the holes 17, compressed air is fed into the control cavity 16, under pressure of which the central valve 4 moves to its highest position, compressing the spring 13.

Compressed air in the central cavity 2

5 is combined with compressed air in the supravalvular cavity 12 and impulse rushes through the central exhaust hole 6 towards the knockout of the central part of the mold, i.e. molding parts

0 a mixture 23 filling the central part of the casting 24 of the annular profile. The molding mixture 23 flies out of the mold, and the casting 24, partially freed from the molding mixture, passes to the crosspiece 22 of the flask 21 (Fig. 2).

In connection with the discharge of compressed air from the supravalvular cavities 12, the peripheral valves 5 are 0.1-0.2 s after the compressed air pulse from the central cavity 2

0 moves to the extreme position. An impulse occurs that knocks out mold sand 23 from the casting mold (FIG. 3).

Example. Through the hole 18, the central cavity 2 and the supravalvular cavity

12 are filled with compressed air, under pressure of which the peripheral valves 5 are pressed against the peripheral exhaust ports 7.

Through the opening 19, the peripheral cavities 3 are filled with compressed air. Upon reaching a predetermined pressure of compressed air, the device is considered to be prepared for knockout.

In order to knock out the casting 24 from the mold, the supply of compressed air through the openings 18 and 19 is stopped and fed through the opening 17 into the control cavity 16, under pressure of which the central valve 4 moves to the extreme upper position, compressing the springs 13. Compressed air From the central cavity 2 and the compressed air from the supravalvular cavities 12, the combined pulsed flow rushes through the central exhaust hole 6 and knocks the molding sand 23 of the central part of the mold through the central part of the casting 24 ring braznogo profile. The molding mixture 23 is knocked out of the mold, and the casting 24, partially freed from the molding mixture, is lowered onto the cross-box 22 of the flask 21 (Fig. 2).

In connection with the discharge of compressed air from the above-valve cavities 12, the peripheral valves 5 move 0.1-0.2 s after the compressed air pulse from the central cavity 2 to the extreme upper position. An impulse occurs, which knocks out the mold from the mold sand residue (Fig. 3). There is no impact on the tooling, since the casting 24 after the first part of the pulse is located on the crosspiece 22. The central valve 4 is under the influence of the spring 13

occupies the original position. Instead of the embossed casting mold under the body 1 serves the next, unbroken. Then the cycle repeats.

Compared to the prototype, the technical and economic advantages of the proposed method and device are reducing the overhead loss of compressed air by an average of 12% and increasing the service life of the snap-in tool by at least 3 times.

Claims (2)

1. A method for knocking out castings from casting molds, mainly ring-shaped, which includes discharging compressed air and supplying a pressure pulse to the surface of the mold, characterized in that, in order to reduce unproductive compressed air losses and increase the service life of the snap-on tool to the periphery, and the pressure pulse in the center is combined with the discharge of compressed air from the supravalvular cavities, while the pressure pulse in the periphery is delayed by 0.1-0.2 s relative to the pressure pulse n center. 2. A device for knocking out castings from casting molds, predominantly ring-shaped, containing a housing with a flange, a working chamber and valves with pistons, in which, in order to reduce unproductive losses of compressed air and increase the service life of the taper equipment, in the working chamber central and peripheral cavities with valves are made, valve-valve cavities of peripheral valves and central cavity are interconnected, and the valve piston of the central cavity is located in the housing flange.