ES2316040T3 - PRESSURE FOUNDING MACHINE OF COLD CHAMBER WITH DEVICE FOR THE ANCHORAGE OF THE MATRIX CAP. - Google Patents

Abstract

A cold chamber die-casting machine for light alloys includes a sleeve (1) that fits into the base of a mold (2) and into the fixed platen (3) of a press, the position of the sleeve (1) being defined by a peripheral centering collar (4) that fits into a corresponding seat formed in the fixed platen (3) and/or in the base of the mold (2), as well as locking means suitable to make the sleeve (1) integral with the fixed platen (3) of the press, such as a ring (9) secured on the sleeve (1) by means of a thread, key or the like and arranged so as to abut against the external side (5) of the fixed platen (3). In this way, the injection and maintenance force is directly transmitted to the fixed platen (3) of the press and not to the mold (2), so as to prevent the risk of fall of the mold (2), to prevent the rotation of the sleeve (1) and to have the possibility of using the force of the press itself in case of difficult removal of the sleeve (1) from the mold (2).

Description

Cold Chamber Die Casting Machine with device for anchoring the die bushing.

The present invention relates to machines of cold chamber die casting for light alloys and in particular to a device for anchoring the bushing of the matrix on the fixed press plate.

It is known that a cap for a machine die casting consists of a hollow cylinder open in the ends and provided with a peripheral collar, to center the fixed press plate cap or mold base as well as a side hole at the rear end to pour into the inside the molten metal to be injected into the mold by means of an injection piston that moves alternately in the inside of the cap. The cap is simply inserted into the inside your seat and then lock inside by the mold itself that is anchored in the fixed plate of the press.

The caps that are currently used they can be essentially of two types: a compound cap that It consists of two or more pieces with a coupling male / female, a first piece being coupled with the mold and a second piece with the press, or an integral cap that is constituted by a single piece simultaneously coupled with the mold and with the press.

With these two known caps the force exerted by the piston to inject the metal and maintain the pressure during the cooling phase it is transmitted to the mold and so both its devices for anchoring on the fixed plate of the press, through the centering collar mentioned above or to through possible reduction rings. This force is transmitted to the mold through the cap, at least in part, mainly for two reasons: a) when the mold is opened, in each machine cycle, during hydrostatic feed load accompanying the stage due to friction between the load feed hydrostatic and bushing, and b) in the case of seizure of the injection piston inside the cap

In the first case, being a cyclic tension and periodically, can cause loosening of the anchoring system mechanical that possibly results in the fall of the mold, or so less requires a periodic interruption of the cycle of operation only to verify the condition of the anchoring system. In the case of a magnetic anchor, since the center of gravity of the anchoring force generally does not match the point of application of the injection force, a moment is generated of torsion of extraction with the possible fall of the mold.

In the second case the injection force complete is transferred to the mold and from there to the anchoring system of it, but the latter is generally not sized to withstand all the force generated by the steering system, also because it is typically an impulsive type of force. This results in the breakage of the anchoring devices with the fall of the mold and deformation or breakage of parts of the fixed plate of the press (for example, T-shaped grooves, threads).

It should be considered that the cap has to be replaced periodically due to wear but the seizures between the mold and the bushing caused by the deformation or expansion of the latter may arise in this functioning. This implies the need to extract the whole mold and the press cap, in order to remove the cap of the mold by other procedures and with other devices.

The aforementioned forces also they can cause a cap rotation with respect to the mold or the press and this causes a loss of reference for the device metal load As a consequence, said device can pour inside the bush a lower amount of molten metal to the designed quantity, since the orifice of metal inlet

The rotation of the bushing is a problem that feels particularly in the case of caps in which the metal discharge inside the mold occurs through a radial hole in addition to one axial hole. In fact, the possible misalignment between the socket outlet and the mold inlet it can cause turbulence in the molten metal and therefore a poorer quality of the foundry.

Therefore the object of the present invention It is to provide a cold chamber die casting machine which overcomes these disadvantages. This object is achieved through of a machine provided with means for locking the bushing for anchor it on the fixed press plate even in the absence of the mold. Other advantageous features of the present invention are set forth in the dependent claims.

The main advantage of this machine is that the injection and maintenance force is transmitted directly to the Fixed press plate and not to mold. In this way, the risk of mold fall and deformations are minimized of the fixed press plate.

A second significant advantage of the machine according to the present invention results from the fact that the means of blocking also prevents the rotation of the bushing, thereby ensuring loading the correct amount of molten metal and the absence of turbulence in the mold inlet which results in a quality Improved foundry.

An additional advantage of said machine is the possibility of using the strength of the press itself in the case of a difficult removal of the mold cap. In other words, since the locking means anchor the bushing to the plate fixed press even in the absence of the mold, it is possible decouple the mold from said fixed plate while maintaining anchored only on the mobile plate and then open the press so that the cap of the mold is always easily removed.

Still another advantage of the present machine is its reliability and structural simplicity, given that the means of lock can preferably be integrated inside the cap in a simple and economical way without requiring substantial modifications of the press.

These and other advantages and characteristics of the cold chamber die casting machine according to the present invention will become more clearly apparent to those skilled in the art from the following description detailed of two embodiments thereof with reference to the attached drawings, in which:

Figure 1 our a sectional view Schematic longitudinal of the two types of bushings of the prior art;

Figure 2 shows a sectional view schematic longitudinal of a first embodiment that includes an integral cap; Y

Figure 3 shows a sectional view schematic longitudinal of a second embodiment that Includes a compound cap.

With reference to figure 1 it is observed that a Conventional bushing 1 for pressure injection machines can be of the integral or compound type, that is to say constituted by a first piece 1 ', which fits at the base of mold 2, and a second 1 '' piece that fits on the fixed plate 3 of the press. In both cases a peripheral centering collar 4 that fits inside is provided of a suitable seat formed on the inner side of the fixed plate 3 or at the base of mold 2 and is covered by the latter. Further, a hole is formed near the outer side 5 of the plate 3 side 6 for pouring molten metal, which is injected into  the mold by an injection piston 7 that moves alternatively inside the bushing. Molten metal flows out at the opposite end through a hole 8 that it can be axial, as in figure 1, or radial or both.

This figure clearly shows what has been explained in the introduction of the present report, that is the mode in which the thrust of the piston 7 or the pull exerted by the hydrostatic feed load, when the last one is taken to through hole 8 at the time of mold opening, it is transmitted to mold 2 and therefore to its anchoring system, to through centering collar 4.

With reference now to figures 2 and 3, note that the novelty of the casting machine at pressure according to the present invention is the provision of means of locking of the bushing 1 to anchor it on the fixed plate 3 of the press even in the absence of mold 2. More specifically, in the first embodiment illustrated in figure 2, said locking means consist of a ring 9 that rests on the outer side 5 of the fixed plate 3 and is fixedly attached to the cap 1 through any known suitable means, such as for example a thread, a key or the like.

In the second embodiment illustrated in Figure 3 the locking means are integrated into the own cap, since it is divided into two pieces with one back piece 10, in which the hole 6 is formed for the molten metal, provided with an increased diameter and length enough to rest on the outer side 5 in the same way as the ring 9 mentioned above.

Therefore it is clear that any force that act on the bushing 1 in the direction of the mold 2 will not be transmitted to the latter through centering collar 4 but by the opposite will be to the fixed plate 3 through ring 9 or the back piece 10.

It should be noted that many can be contemplated other more complicated systems to provide the means of lock anchoring bushing 1 on fixed plate 3. For example, magnetic or hydraulic devices similar to those used for anchoring the mold 2, or mechanical devices different from those illustrated earlier in this document, such as a bayonet coupling or an outer conical profile of the back piece of a composite bushing that is inserted from the outer side 5.

However, the two embodiments illustrated have the advantage that they do not require any modification  of the die casting machine beyond bushing 1, by which are particularly preferable as improvements for existing facilities

It is therefore clear that the forms of embodiment described above and illustrated in that document of the die casting machine according to the invention are only susceptible examples of various modifications. In particular, the exact shape and arrangement of the locking means can be change freely according to the specific needs of manufacturing, for example, getting retention between the bushing 1 and fixed plate 3 more downstream of hole 6 for molten metal or even upstream of it.

Claims (4)

1. Cold chamber die casting machine for light alloys including a bushing (1; 1 ';1'') that fits inside the base of a mold (2) and inside the fixed plate (3) of a press , the position of said bushing (1; 1 ';1'') being defined by a peripheral centering collar (4) that adjusts within a corresponding seat formed on the inner side of the fixed plate (3) or on the base of the mold (2), characterized in that it additionally includes suitable locking means for anchoring the bushing (1; 1 ';1'') in said fixed plate (3) of the press even in the absence of the mold (2). 2. Die casting machine according to claim 1 characterized in that said locking means consist of mechanical devices fixedly attached to the bushing (1; 1 ';1'') and sized and arranged so that they rest against the outer side (5) of the fixed plate (3). 3. Die casting machine according to claim 2, characterized in that said locking means consist of a ring (9) fixed in the bushing (1; 1 ';1'') by means of a thread, a key or the like. 4. Pressure casting machine according to claim 2 characterized in that said locking means consist of a rear part (10) of the bushing (1; 1 ';1''), part in which a hole (6) is formed for molten metal