EP0121128A2 - Press for making dishes or the like - Google Patents

Abstract

Described is a press for the manufacture of plates or the like. With a press ram that can be brought up for pressing against a counter mold, which is shaped in accordance with the inner shape of the plate to be pressed or the like Dimensions of the edge of the finished plate adapted edge clamped, elastic membrane, which is provided with an annular groove corresponding to the foot of the plate and on the powdered porcelain mass with a press ram moved at a distance within the limits given by the clamping, which of the Membrane covered cavity can be filled with a pressure medium which can be pressurized after moving the ram to the powdered porcelain mass distributed on the membrane. The press ram has a coating which is provided on the edge with an annular bulge that bulges toward the membrane. Compared to this annular bead, a self-contained annular groove can be provided in the edge of the membrane.

Description

The invention relates to a press for the production of plates or the like. With a press ram that can be moved up to press against a counter mold, which is shaped according to the inner shape of the plate to be pressed or the like, and with a cavity closing in the counter mold on it the dimensions of the edge of the finished plate, clamped edge, elastic membrane, which is provided with an annular groove corresponding to the foot of the plate and on the powdered porcelain mass with a ram driven at a distance from it the limits given by the clamping can be distributed, the cavity covered by the membrane being able to be filled with a pressure medium which can be pressurized after the press ram has been moved up to the powdered porcelain material distributed on the membrane.

Such a press is generally known from DE-PS 26 27 160.

The plates produced on a press according to DE-PS 26 27 160 have at the edge a pressure wedge-shaped tapered edge which must be removed in a further operation using several cleaning tools so that the desired rounding of the plate edge or rim is created. Such post-processing is necessary for plates with a fixed edge, i.e. practically impossible with a curved edge.

The reason why the edge of the plate runs out in a wedge-shaped manner is that the pressed plates open up slightly after the pressing process, i.e. that its outer diameter becomes larger, so that when the rim of the plate is held by the membrane or other parts of the press, the lifting of the plates is considerably more difficult and the plates may be damaged when lifting off. If, however, the edge of the plate runs out in a wedge shape, the clamping forces are correspondingly lower. However, such tapered edges on the finished plates are undesirable and must be rounded again with considerable material removal. If the edge is fixed, removal of material is practically impossible, especially in the recesses.

The object of the invention is to make the arrangement in the edge area so that a plate edge is formed which only needs to be reworked on the underside of the plate, but otherwise rests freely on the membrane after the pressing die has been moved off and can therefore be removed without difficulty.

This object is achieved in that the press ram has a coating which has an annular bulge bulging in the directions on the membrane at the edge. This annular bead is preferably a hollow bead.

This ring bead sits on the membrane when the ram is placed. Since the membrane is acted upon by pressure medium on the underside, the annular bead is displaced upwards, whereby it only moves in the direction of the filling material, i.e. the ceramic material on the membrane can dodge inside. Thus, when it is pressed flat against the press ram, it shifts the edge of the pressed material somewhat inwards. If the pressure forces of the pressure medium are released, the ring bulge can reform because the membrane also deforms again. The plate can relax freely and the risk of damage to the plate when relaxing is eliminated.

Attempts have already been made to solve the problem addressed by the present invention according to DE-OS 29 33 226.1 by forming a self-contained annular groove in the edge of the membrane on the surface facing the press ram, the membrane below this annular groove primarily with Pressure medium is applied.

However, it has been shown that this solution could not yet be the final solution because, according to this teaching, the edge or rim of the plate is placed in the membrane, which, according to current experience, cannot be achieved for Feston relief plates. It turns out that the pressed plates rise by about 0.8 to 1.8%, so that their outside diameter becomes correspondingly larger and the rim of the plate is thus held in place by the membrane.

However, the teaching according to DE-OS 29 33 226.1 can advantageously be combined with the teaching according to the invention according to claim 1 and / or 2, since then the ring bead on the press ram when it is placed on the membrane in the ring groove arranged opposite it. Since the part of the membrane lying under the annular groove can primarily be acted upon by pressure medium, the annular bead is specifically shifted upwards and can practically only in the direction of the filling material, i.e. the ceramic material, dodge inside. The effect that can be achieved by the basic idea of the invention is thus perfected and strengthened.

In the course of the further development of the press according to the invention it has been found that the effective surface of the ram after filling the membrane and placing the ram before the start of the pressing process can be reduced in diameter by applying pressure to the membrane, so that after the pressing process when relaxing, the coating on the outer circumference is enlarged if the press ram has a coating on the circumference, which is provided on the edge with a bulging ring in the direction of the membrane.

The fixation of the coating on the inner stamp part can take place and / or be supported in that the coating of the press ram in the area of the inclined surface has a projection that lies over this inclined surface, which is hooked at its end via a bead in a groove of the inner stamp part .

From DE-OS 31 45 199 it is already known to divide the press ram into an edge part and into an inner part and to provide the edge part with an inner and outer oblique inner boundary surface while the inner stamp part is under spring action. The reduction in the diameter of the effective surface of the press ram is only slight in this arrangement. However, this solution is not fully satisfactory in continuous operation.

• Fig. 1 einen Teilausschnitt aus einer Vertikalpresse im Längsschnitt, wobei auf die über der Gegenform sitzende Membran keramische pulverförmige Masse aufgefüllt ist und der Preßstempel sich im Abstand von der Gegenform befindet;
• Fig. 2 die Presse im geschlossenen und mit Druckmittel beaufschlagten Zustand im Ausschnitt;
• Fig. 3 die noch geschlossene Presse, wobei jedoch das Druckmittel abgelassen ist;
• Fig. 4 einen Teilausschnitt aus einer weiteren Ausführungsform einer Vertikal presse in einem Zustand ähnlich dem nach Fiq. 1;
• Fig. 5 die Presse nach Fig. 4 im geschlossenen und mit Druckmittel beaufschlagten Zustand im Ausschnitt; und in
• Fig. 6 die noch geschlossene Presse, wobei jedoch das Druckmittel abgelassen ist.

The drawing shows in

• Figure 1 shows a partial section of a vertical press in longitudinal section, ceramic powdery mass is filled on the membrane sitting above the counter mold and the press ram is spaced from the counter mold.
• Figure 2 shows the press in the closed and pressurized state in the cutout.
• 3 shows the press which is still closed, but the pressure medium has been released;
• Fig. 4 shows a partial section from a further embodiment of a vertical press in a state similar to that according to Fiq. 1;
• FIG. 5 shows the press according to FIG. 4 in the cutout, in the closed and pressurized state; and in
• Fig. 6, the still closed press, however, the pressure medium is released.

1 with the counter-shape is designated on which a retaining ring 2 is placed, which holds the membrane 3 via an attachment 4. The membrane 3 is also held in place by a ring 5 in the insert 6.

The insert 6 has openings so that the pressure medium can be brought into effect directly below the membrane. The membrane is provided on the side opposite the press ram with a circumferential annular groove 7.

The press ram 10 has a coating 8 with an annular bead 9 which is arranged exactly opposite the annular groove 7. In the exemplary embodiment shown, this annular bead 9 is a hollow bead.

If the press ram 10 sits on the membrane 3 together with the ring 11, the membrane 3 is fixed at the edge area, so that when the underside of the membrane is acted upon with the aid of a pressure medium, the plate schematically indicated at 12 from the powdery one indicated at 13 in FIG. 1 Porcelain mass is created.

When the isostatic pressure is applied, pressure medium passes under the annular groove 7 and bulges the membrane 3 upwards in this area. At the same time, the annular bead 9, such as results from Fig. 2, pressed flat and deformed inward so that the plate edge 14 is shifted inward. In the stage shown in Fig. 2, the finished pressed plate is produced. In the next stage, the pressure medium is released, so that the annular bead 9 in the press ram coating 8 and the annular groove 7 of the membrane deform back into the starting position, as can be clearly seen from FIG. 3. The annular bead material, as can clearly be seen in FIG. 3, is removed somewhat from the edge of the pressed plate 12.

The plate rim 14 is thus released and the plate can be removed without difficulty after opening the press.

In Fig. 4, 21 is the counter-shape, on which a retaining ring 22 is placed, which holds the membrane 23 via an extension 24. In addition, the membrane 23 is held in place by a ring 25 in the insert 26.

The insert 26 has openings so that the pressure medium can be brought into direct contact with the membrane 23. The membrane is provided with a circumferential annular groove 27 at the edge.

In this exemplary embodiment, the press ram consists of an inner ram part 30 and a wedge ring 31 surrounding this inner ram part 30, which protrudes in the direction of the counter mold 21 and has an inner boundary surface 32 which runs from the inside to the outside. The apex 33 is flattened. The wedge ring 31 is fastened by means of screws 34 to the base body 35 of the press ram. Inside the wedge ring is the inner stamp part 30, which is also on the base body 35 by means of screws 36, but with play and against Effect of compression springs 37 is attached. A coating 38 extends over the inner punch part 30 and the wedge ring 31 and has an annular bead 39 above the apex 33 of the wedge ring 31. The base body 35 is surrounded by a spring-mounted ring 41. When the press is open, the porcelain mass indicated at 43 is placed on the membrane.

The coating 38 has, at the transition from the inner press part 30 to the wedge ring 31, an extension 40 pointing into the inside of the press die, which is fixed to the inner die part 30 with a bead 42 at the end of the inclined surface which is essentially parallel to the boundary surface 32.

During pressing, the ring 41 first sits on the edge of the counter-shape 21 and the outermost edge of the membrane 23, as a result of which the membrane 23 is fixed in the edge region. When the press ram is lowered further, the coating 38 strikes the filled porcelain mass over the inner ram part 30 and is raised relative to the wedge ring 31 against the action of the springs 37, as a result of which the coating 38 is displaced inward in this area. After the press has been closed, pressure medium is applied under the membrane 23 and the finished plate 42 is produced from the porcelain mass 43 (cf. FIG. 5).

When the isostatic pressure is applied, pressure medium also passes under the membrane 23 in the region of the annular groove 27, so that the membrane 23 bulges. At the same time, the annular bead 39 is pressed flat. Enclose all corresponding shaping parts of the press thus the porcelain mass, so that the plate is also fully formed on all sides (cf. in particular Fig. 5).

If the pressure of the pressure medium below the membrane 23 is released, the springs 37 press the inner stamp part 30 and the coating 38 with the annular bead 39 back into the starting position and the plate rim 44 is released, as can be seen in FIG. 6.

Of course, the press according to the invention is not only suitable for producing plates with a festonized edge, but can also be used advantageously for plates with a smooth edge, because the problem of demolding also plays a role here. The invention is also not limited to vertical presses. The problem described at the outset also occurs with horizontal press training and can be solved according to the invention.

Claims (5)

1. Press for the manufacture of plates or the like. With a press ram which can be moved up against a counter mold and which is shaped corresponding to the inner shape of the plate to be pressed or the like, and with a cavity which closes a cavity in the dimensions of the edge of the finished plate, clamped edge, elastic membrane, which is provided with an annular groove corresponding to the base of the plate and on the powdered porcelain mass with a ram driven at a distance from it within the limits given by the clamping, which of the membrane Covered cavity can be filled with a pressure medium, which can be put under pressure after moving the press ram onto the powdered porcelain mass distributed on the membrane, in that the press ram (10) has a coating (8) on the edge with a in the direction of the Membrane (3) bulged ring bead (9) is provided. 2. Press according to claim 1, characterized in that the annular bead (9) is a hollow bead. 3. Press according to claim 1 and / or 2, characterized in that the edge of the membrane (3) on the surface facing the press ram (10) is provided with a self-contained annular groove (7) which with the annular bead (9) cooperates. 4. Press according to one or more of the preceding claims, characterized in that the pressing die on the circumference has a wedge ring (31) which is fixed with it and projects in the direction of the counter-shape (21) and which has an inner boundary surface (32) which extends obliquely from the inside to the outside. has, over the flattened vertex of the annular bead (39) of the coating (38), that within the wedge ring (31) an inner stamp part (30) resiliently mounted in the direction of movement of the press ram with one of the oblique boundary surface (32) of the wedge ring (31) Corresponding, outwardly inclined surface is arranged, and that the coating (38) is fixed to the inner stamp part (30). 5. Press according to claim 4, characterized in that the coating (38) of the press ram in the region of the inclined surface has an overlying this inclined surface approach (40) which at its end via a bead (42) in a groove of the inner stamp part (30) is hooked.

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