EP0394121A1 - Container for casting using an expendable pattern - Google Patents

Abstract

The container comprises a peripheral and ribbed annular chamber (2), permitting suction of the gases upon casting, and a working bottom (4) consisting of a knocking-out gate valve and a casting device (8). <IMAGE>

Description

The present invention relates to the field of casting parts with a lost model, in particular according to the process known as "lost foam". It relates more particularly to an improved tray for casting parts which overcomes the drawbacks of tanks commonly used in foundries. These are generally metal trays with single walls which are stiffened by means of thick, very heavy sheets. With these bins, the parts are poured by gravity and the release most often by inverting the bin. In addition, the suction of the pouring gases is carried out by the bottom of the tank and the vibration by a vibrating table supporting the tank.

The invention proposes an improved tank which comprises, according to an essential characteristic, an annular, peripheral and ribbed chamber allowing in particular an effective aspiration of the pouring gases, and a working bottom consisting of a valve with a release valve and a casting device.

This structural arrangement ensures efficient suction of the gases on casting, around the periphery of the tank. On the other hand, it makes it possible to stiffen the box container even more for appropriate simple ribbing, while lightening it optimally.

The bottom of the tank, thus freed from the suction function, can fulfill functions such as release and low pressure casting.

• - la figure 1 représente une vue en coupe verticale d'un bac conforme à l' invention ;
• - et le figure 2 représente une vue partielle de dessus en coupe suivant le plan 2-2 de la figure 1.

Other particularities and advantages of the invention will emerge more clearly from the following description of a preferred embodiment, given by way of nonlimiting example, with reference to the appended drawings in which:

• - Figure 1 shows a vertical sectional view of a container according to the invention;
• - And Figure 2 shows a partial top view in section along plane 2-2 of Figure 1.

As illustrated in these two figures, a rectangular cross section present on the periphery of its four faces, an annular chamber 2. This is used for the suction of gases for casting by allowing better evacuation of the casting gases released in particular by models. This aspiration is effected all around the models with a large effective gripping surface.

The search for significant rigidity combined with great lightness for this bin is facilitated by ribbing without difficulties. This provides better transmission of vibrations for better clamping of the sand. Load weights can also be omitted for important parts such as crankcases.

This tank is provided with a working bottom which includes a slide valve 6 for release, and a pouring device 8.

This arrangement provides two significant advantages. It allows a release without turning the tank, which eliminates heavy handling systems and facilitates the control of the emission of fines and fumes in the workshop.

It simplifies the casting system, in particular by reducing the quantity of useful polystyrene and consequently of gas to be evacuated.

In Figures 1 and 2 also appear:
- four grids 10 provided for suction, - and ribs 12 distributed all around the tank.

Claims (2)

1. Bin for casting a lost model, of the suction or vacuum type, characterized in that it comprises, in combination: a) a peripheral and ribbed annular chamber (2) allowing in particular an efficient suction of the gases during casting, b) and a working bottom (4) consisting of a slide gate valve (6) and a pouring device (8). 2. Tray according to claim 1, characterized in that the casting device (8) is suitable for casting of the low pressure type.

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