Metal founding – Means to shape metallic material – Including means to assemble mold parts
Patent
1981-03-05
1984-07-31
Lin, Kuang Y.
Metal founding
Means to shape metallic material
Including means to assemble mold parts
164137, 164369, B22C 910
Patent
active
044624557
DESCRIPTION:
BRIEF SUMMARY
SUMMARY OF THE INVENTION
The invention refers to a permanent mold with at least one core pulling device placed in the mold wall.
Pulling devices in permanent molds are known already and possess among others the advantage, that they are fixed exactly in the hollow space of the mold and can not be shifted. Corbelling cavities, that is cavities which increase toward the mold cavity, can, however, not be made. They are, however, very important as anchoring slots and similar in wearing parts consisting of hard casting materials, since such materials cannot be machined by normal tools. Such corbelling cavities up to now had to be made by means of sand cores, a procedure which is rather problematic. Due to the different heat conducting capabilities of the molding material and the metal, the solidification and the saturation are being disturbed. Also, an exact fixation (security against swimming-up) and positioning by means of core marks as well as the creation of gas cause difficulties.
Therefore, it is the object of the invention to propose a permanent mold, making it possible to produce corbelling cavities and threads economically by avoiding the disadvantages cited above.
This object is being realized by means of the teachings described in the first patent claim.
Advantageous embodiments of these teachings are described in the remaining claims.
The invention makes it possible to economically produce corbelling, e.g. hammer head bolt shaped (with or without interior thread) cavities in castings. The complicated, insecure and time consuming fixing is no longer necessary, so that time is being saved and the number of rejected products is being diminished and, therefore, the production economy is being improved. By means of the metal stud the form material (core sand) is being cooled. By a simple test procedure it is possible to reduce the thickness of the sand jacket to a very low value. In that way the cooling is being improved, and an increased cooling is possible by means of water supply. Thereby, a lower amount of gas is being produced, and the shrinking is not being disturbed after the core holding device in known manner (e.g. by means of toothed bar rack or hydraulic cylinders) has been retracted from the wall of the permanent mold. This is due to the fact that the resistive force acting against the shrinking, as compared to earlier procedures, has been reduced, so that the cast is allowed to decrease free from any resistive force. In any case the sand jacket can emerge in that it collapses and is being destroyed. The method can be applied to all casted materials, but particularly advantageously to iron alloys and basalt.
In the following an embodiment of the invention is being described with reference to the drawings, in which
FIG. 1 shows a partial section through a permanent mold with two core pulling devices, and
FIG. 2 shows parts of two sections of means for preventing a rotary movement of the core pulling device or sand jacket.
A permanent mold has a side wall 1, in which two sliding core pulling devices 2 and 3 are located, each comprising a core holding device, a stud 9 extending into the mold cavity 8, both of metal, advantageously of a copper-chrome-alloy (CuCr 1) and a jacket 10 of molding sand. Depending on the specific requirement the stud 9 can be screwed into the core holding device 7 by means of a screw stud 15 (core pulling device 2) or the stud 9 and the core holding device 7 can be formed in one piece (core pulling device 3). The jacket 10 is being pushed over the pushed-in stud 9 from the interior side of the mold.
Shortly after pouring of the melt, when the solidification has produced a crust on the wall 1 and around the sand jacket 10 of sufficient thickness, the core pulling devices 2 and 3 are operated in the direction of the arrow 16, so that the sand jacket remains in the cast. When the devices 2 and 3 are operated in the opposite direction it is important that the jacket 10 does not rotate. Therefore, the jacket 10 must be nonrotatable on the stud 9 and the holding device 7 must
REFERENCES:
patent: 818413 (1906-04-01), Caldwell
patent: 3098270 (1963-07-01), Bauer
patent: 3374827 (1968-03-01), Schebler
patent: 3528637 (1970-09-01), Bedford
Fischer Erwin
Henych Ivo
George Fischer Ltd.
Lin Kuang Y.
Seidel Richard K.
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