CS200057B1 - Mould for centrifugal casting - Google Patents

Description

The invention aa relates to a mold for the centrifugal casting of objects of slightly conical or pyramid-shaped pillar shape from hardened casting materials, for example electric conductive poles of reinforced concrete.

The presently known centrifugal casting objects of a slightly conical compression shape are mainly limited to casting in closed molds. These usually consist of a conical sheet of sheet steel welded along a surface line with radially welded tires of the same outer diameter.

The inner surfaces of such molds must be smoothly worked after welding and, in addition, must be provided with a perfectly continuous and relatively thick separating layer before each / filled concrete, preventing both the bonding and the hardening of the concrete. steel sheet of the mold and, on the other hand, facilitating the ejection of the finished product from the mold. Mineral fats, waxes or other materials are usually used for this purpose. The disadvantage of manufacturing masts using such molds is the laborious preparation of molds for casting the product. The preparation of the molds requires cleaning of the inner surface after each casting, followed by laborious application of the separating agent. A further disadvantage is the relatively high consumption of the separating agent and the rough, non-aesthetic, yet unacceptable, for a relatively long time, the slippery surface of the products produced in this way.

With the other types of closed molds, the tapered molds were finely machined from the outside, but in particular from the inside, to which spinning rims of the same diameter were fixed, but at unspecified axial distances. A fitting together with a paper or plastic insert or an oel thin-walled foil is pressed into the inner cone of the mold ea and is pushed into the inner surface of the undivided mold by the centrifugal pressure of the concrete mixture. They are extruding the cured workpiece a and extruding them together with the inserts which are then removed from the workpiece surface.

The disadvantage of such molds consisted mainly in the fact that in the very high flexibility of the inserts of all the materials mentioned, the workpiece adhered to the inner shell of the cone was such that even the slightest deformation of the closed shell practically prevented the cured product from being pressed out of the mold.

In addition, the machining of the inner surface of the molds was very costly and encountered considerable technological problems, since the machining of the welds had to be carried out only after welding the cone and the technology of manual grinding, respectively. polishing is the most costly form of metalworking in aúčasnoati.

Another type of mold is a non-closed mold, consisting of a cone-shaped casing nicely rounded to a closed state and not welded to a long time. Such shells enclose the molds aa in a vigorous manner. This may be by sliding the hoops of the same outer but different inner diameter in the direction from the thinner end of the casing, progressively from the hoops and the largest opening to the smallest. An improved alternative of molds and split casing is such that the casing is wrapped in any basket, welded from the inner tire with various outer and inner hoops! diameters with longitudinal angles, which thus form conical bushes. The outer rims of the same outer diameter, welded on the positioning machine and the spinning of the basket in the blasting machine are welded to this brush. A disadvantage of the split-shell molds with this way of closing the tire is that the conical tire can easily be deformed, which in turn makes it difficult to insert and slide the tires out of the tire, respectively. it makes it difficult to insert and remove the housing into the conical ribbing of the basket housing. The main negative feature of these solutions, however, is the impossibility of perfect thinning of the lateral slot of the mantle and the loss of the thin concrete mixture through this slot during the blasting process. Spraying cement milk softens the product material and valuable binder, thereby depreciating the product while contaminating the spinning device and the workplace. Masts made in this way have a lower lifetime.

Said type of split shell molds has been further refined by a mold comprising a basket similar to baskets wrapped in the preceding text in which the conical shell clamps are provided by hollow rubber bodies which inflate when the shell is closed and the air is discharged therefrom. The advantage of this solution is the fact that it also allows the production of cylindrical or prismatic products, but does not prevent the possibility of loss of the binder from the concrete mixture and, moreover, causes a considerable imbalance of the mold due to gravity of the casing. spinning machine. The elastic closures of the casing cause the casing to oscillate in the contact surfaces, which causes the concrete mixture to leak when centrifuged.

The above drawbacks are overcome by the invention for the centrifugal casting of conical or pyramid-shaped casting products, in particular reinforced concrete masts, which consists of a closed untreated outer casing provided with constant collars at constant axial distances and a split inner casing, non-deformable and non-deformable casting material also unworked.

The advantage of this solution is the high rigidity of the construction, the possibility of a permanent state of absolute balance of the mold and thus a long service life. The double wall of the casing has practically twice the deformation resistance of the unclosed casing, prevents the loss of concrete mixture and thus reduces the percentage of reject, increases the product value, does not contaminate the centrifuge and the workplace. The advantage is also the simplified, simplified and hence less costly production of molds, which are practically made up of only two components, properly treated.

They are a sheath and a collar, since the collars differ only in the bore diameter of the opening and the shells differ in that one of them is longitudinally welded, ie closed, and the other, after sliding, is twisted at both the narrower and wider ends.

A saler advantage of the new solution is that the more sealed closed jacket of the weld only from the outside without boiling the weld root, so that the weld does not flow into the weld inside the mold, thereby eliminating the necessity of any internal treatment of the outer jacket.

This reduces production and labor productivity. The considerable state of balance of the mold, which is of a permanent impact, increases the service life of the molds but also of the centrifuge and guarantees good product quality.

In the accompanying drawing, FIG. 1 is a longitudinal cross-sectional view of the dual-skin mold of the present invention. Fig. 2 is a cross-sectional view of the mold plane perpendicular to the longitudinal axis of the mold in a state where the non-closed casing is fully inserted into the mold, i.e. when the mold is closed. Fig. 3 is a cross-section of an open mold, i. the inner sheath is pulled out of the outer sheath.

The conical outer shell 12 is at certain distances dependent on the positions of the respective guide rollers of the downstream devices, e.g. In the outer casing 13, the inner casing 11 is inserted so deep that its separating surface slot 14 is completely closed.

In the manufacture of poles, the outer surface of the inner casing 11 is provided with a lubricant to facilitate the displacement of the inner casing 11 in the outer casing 12. At the bottom is the lubricant provided with the inner casing 11 around the edges of the slot 14. prevents the casting material from entering the micro-gap between the outer sheath 12 and the inner sheath 11.

The inner surface of the inner casing 11 is provided with a thin layer of separating agent preventing the cast article from joining the inner casing 11. After the product has cured in the mold, the product together with the inner casing 11 from the outer casing 12 extends, the inner casing opens itself and the quality product can Remove the mold without the inner sheath 11. Then check the mold, remove any residual dirt, lubricate and separating layers, adjust the inner sheath 11 into the outer sheath 12 as far as it will go and cast another product. The object of the invention can be used, in particular, in building organizations and panels in the manufacture of articles of concrete or other casting materials.

Claims (3)

OBJECT OF THE INVENTION A mold for centrifugal casting of conical products, in particular electro-conductive masts made of reinforced concrete, characterized in that it consists of a closed, uncoated outer casing (12), provided at constant axial spacings with flanges (13) and uncoated casing resistant to the inner casing (11). by the casting mass. 2. Centrifugal casting mold according to claim 1, characterized in that the unclosed inner casing (11) is made of a two-layer steel-plastic material, the surface provided with a plastic layer forming the outer surface of the unclosed inner casing (11). 3. Centrifugal casting mold according to claim 1, characterized in that the non-closed inner casing (11) is made of fiberglass.