DE2822594C2 - Ball feeder model with a core and a jacket - Google Patents

Description

The invention relates to a ball feeder model with a Core and a sheath according to patent 28 03 247.

According to the main application, ^ as has a ball feeder model a core made of gasifiable foam and a gas-permeable jacket, the au. "a heat-insulating, an exothermic reacting or an initially exothermic reacting and after reaction thermally insulating material is an essential feature of such a ball feeder model is that it only has the advantage of a large volume with a comparatively small surface is demoldable in a split mold. With such a ball feeder model, there is always a requirement Before absorbing the melt, remove the core from the jacket, just around the actual feeder to create, in which melt can enter during pouring, in order to move in when the melt cools down from the feeder the casting mold to flow again and thus avoid disadvantages such as the formation of cavities.

Cases are now conceivable in which the spherical or an essentially spherical shape of the ball feeder is indeed conceivable thanks to a spherical feeder model or at least one with an approximately spherical core because of Their advantages are to be used, but in which a gasification of the material of the core is undesirable or not possible because of low or insufficient gas permeability of the jacket or else is disabled

The invention is therefore based on the object of providing alternative solutions for removing the core from the To create a ball feeder model or from its jacket,

This task is in the case of a ball feeder model with a core and a jacket according to patent 28 03 247 according to the invention solved in that the core - in modification - in one, as a result of the properties of the Material of the body in its shape is reversible or changeable body. By this measure is it is possible to remove the core therefrom without affecting the jacket.

It is already known. Casting molds for precision parts by molding wax models. However, these are very fine parts and that Process takes place because of its considerable difficulties and its great effort only with the Manufacture of precision parts, e.g. B. in the sewing machine industry, Use. The so-called Not to convey lost wax casting.

ίο Thus, according to one embodiment of the invention Method of the body representing the core of the ball feeder model can be melted out, whereby because of Due to the large scope for the melting point, a large number of materials can be used. In In this case, only the already hollow ball feeder model, i.e. its Coat for use.

According to an alternative according to the invention, the body is shrinkable. The shrinkage can be caused by heat, but also by chemical reactions. The body is thereby shrunk down to dimensions that make it possible to remove the body representing the core through the opening of the ball feeder model from this or its jacket. Such a body could for example be made of thermoplastic foam, wherein the shrinkage could be brought about by both heat and solvents.
According to a further alternative embodiment according to the invention, the body consists of a gasifiable material, such as a homogeneous gasifiable material, ie non-foamed gasifiable material.
With all these measures according to the invention, the range of application of the ball feeder model is expanded to such an extent that all conceivable needs can be optimally covered with regard to favorable coordination of the materials of the core and the jacket.

A further improvement of the ball feeder model, for which a zirconium coating on the side of the shell facing the model plate or the model had already been proposed, in order to avoid effects in the event of an exothermic reaction of the shell on the melt, consists in the fact that this layer is comparatively thicker Made of zircon sand or the like and at the same time designed as a knock-off core
The invention is shown schematically and by way of example in the drawing

F i g. 1 a ball feeder model, in section, and
F i g. 2 a different ball feeder model, in section.
According to the drawing, the spherical caster model according to FIG. 1 and the spherical feeder model according to FIG. 1 correspond. 2 in its essential features, the latter representing one of the possible modifications of a spherical biscuit model. Such a modification can result, for example, if a comparatively higher degree of exothermic heat is desired in certain zones of the feeder.

Both ball feeder models have a core 1.1 ', its body can be canceled or changed in its shape due to the properties of the material of this body is like melting out, shrinking, gasifying. The core 1, 1 'is formed from a jacket 2, 2' Surrounded gas-permeable material with heat-insulating and / or exothermic reacting property. An air pressure core 21.21 'is integrated into the jacket 2.2'

I. ³

; - ■; kig molded. A model or a model

| i is the side 22, 22 'of the shell 2, 2 ^{1 to be assigned to the plate}

| i to avoid adverse effects on the melt,

s as an insulating or boundary layer, with zirconium or the like. In the

I. Prepared in a way that a relative to a her-

ys conventional finishing layer zirconium thick layer 3, 3 '

y made of zircon sand or dgL is applied, which is also used as

Κ Tee 4.4 'serves

Ii 1 sheet of drawings

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Claims (5)

Patent claims: 1. Ball feeder model with a core and a jacket according to Patent 2803 247, characterized in that that the core (1) - in modification - in one, as a result of the properties of the Material of the body in its shape is reversible or changeable body 2. Ball feeder model according to claim 1, characterized in that the body can be melted out 3. Ball feeder model according to claim 1, characterized in that the body is shrinkable 4. ball feeder model according to claim 1, characterized in that the body consists of a gasifiable Material, such as a homogeneous gasifiable material, exists 5. Ball feeder model according to claim 1, wherein the jacket on its the model or the model plate facing side with a layer of zirconium or the like. Is coated, characterized in that this layer (3) with a comparatively greater thickness of zircon sand or the like is formed and at the same time as a knock-off core (4) is formed