EP0662027A1

EP0662027A1 - Casting installation and process for pressure-casting ceramic items

Info

Publication number: EP0662027A1
Application number: EP94923733A
Authority: EP
Inventors: Günther Söthje
Original assignee: Erich Netzsch GmbH and Co Holding KG
Current assignee: THURINGIA NETZSCH FEINKERAMIK GMBH & CO. KG
Priority date: 1993-07-22
Filing date: 1994-07-13
Publication date: 1995-07-12
Anticipated expiration: 2014-07-13
Also published as: EP0662027B1; DE59405386D1; WO1995003160A1; DE4324684C1; CN1112780A

Abstract

A plurality of first moulding holders (16), each for a first moulding (22), is arranged in peripherally staggered array to pivot about a tangential axis (B) on a turntable (10) which can be stepwise rotated about a central pivot (A). A corresponding number of second moulding holders (18) for a second moulding (24) each, which can be moved towards and away from an appropriate first moulding holder (16) in order to bring together or separate the appropriate mouldings (22, 24), is arranged on the turntable (10). Beside the turntable (10) there is an unmoulding station (30) with a pivoting drive (90) to pivot a pair of moulding holders (16, 18) to and fro between a casting and an unmoulding position. Tensioners (42, 44) are arranged to pivot about the axis (B) on the moulding holders (16, 18) with the latter and can be locked and unlocked together in pairs by remote actuation. Drives (60, 70, 80) for actuating the tensioners (42, 44) and to move a pair away and towards each other into the unmoulding position of pivoted moulding holders (16, 18) are arranged solely in the unmoulding station (30).

Description

Casting plant and method for die casting ceramic castings

The invention relates to a casting system according to the preamble of claim 1. Such casting systems are primarily provided for casting sanitary ceramic castings such as wash basins, toilet bowls or the like using plastic molds.

From DE 24 58 778 AI a casting plant of this type is known, in which each pair of associated molded part holders is arranged in a frame which has a rocker pivotally mounted on the turntable by means of two pivot pins as the lower frame part, two of which are parallel to each other Has pivot pin made of upwardly extending guide rods as side frame parts and a yoke connecting the two guide rods at the top as the upper frame part. The pivot pins are each mounted on an arm projecting radially from the turntable, and the yoke is attached to the upper end of a stand which is attached to the edge of the turntable and projects vertically upwards in such a way that the guide rods lie in a plane inclined upwards. In this way, a plurality of frames are attached to the turntable at uniform circumferential intervals, each enclosing a pair of mold holders together with the mold parts held by them. On the guide rods of each frame there is a crossbeam to clamp and pull apart the molded part holders enclosed by the frame attached to the associated yoke hydraulic cylinder displaceable. Cast mold parts belonging together lie in a mold parting plane normal to the associated tie rods, which plane is inclined slightly radially inwards against the rotary table. In the course of each working cycle of the casting installation, one of the frames, together with the molded part holders and molded parts enclosed by it, reaches the demolding station. There the traverse of the frame together with the upper molded part holder and the attached upper molded part is pulled up by means of the hydraulic cylinder, and one of the pivot pins of the lower molded part holder is coupled with a pivoting device. As soon as the lower mold part, including the casting therein, is free of the upper mold part, the lower mold part holder, including the lower mold part, is pivoted by a little more than 180 ° by means of the pivoting device, the casting being placed on a trolley which on a lifting table arranged in the demolding station. The lifting table together with the carriage and the casting lying thereon is then lowered, and then the lower molded part holder together with the lower molded part fastened thereon is pivoted up again by means of the pivoting device, and finally the cross member is velvety by means of the hydraulic cylinder attached to the yoke of the frame the upper mold part holder and the upper mold part attached to it are lowered again along the guide rods so that the mold is closed again and ready for refilling with casting slip.

This known casting installation, with its number of frames, traverses and associated hydraulic cylinders corresponding to the number of casting molds, requires a considerable amount of space and has a large inert mass which must be accelerated and stopped again with each of the rotary movements of the rotary table taking place gradually. The pressure medium supply to the numerous hydraulic cylinders attached to the rotary table also requires considerable effort. The invention is therefore based on the object of providing a casting installation which is particularly suitable for die casting sanitary ceramic castings and which is at least as powerful in comparison with the known casting installation described above, but requires less production effort and takes up less space.

The object is achieved according to the invention with the features of patent claim 1.

With the invention it is achieved that the rotary table only has to transport the molded part holders, casting mold parts and associated clamping bodies. All drives for unlocking and locking the clamping bodies and for moving the mold parts apart and together are arranged, like the swivel drive, in the demolding station and are available there for all molded part holders and associated molds rotating with the rotary table, regardless of their number.

Advantageous further developments of the casting installation according to the invention result from the subclaims.

The invention further relates to a method for casting ceramic castings according to claim 10. The elastic deformation of the mold parts according to the invention before the mold is opened has the effect that the cast part formed therein is compressed and consequently obtains a better surface quality and is more easily detached from the mold parts , if these are separated from each other immediately after their elastic deformation. This method can in principle also be carried out on the known casting installation described at the outset, provided that the frame and associated hydraulic cylinders are dimensioned sufficiently strong to elastically deform the casting mold parts in the required manner. Such a dimensioning of the frame and hydraulic cylinder would increase the manufacturing costs and space requirements of the known casting installation even further. On the other hand, the casting The system for carrying out the method according to claim 10 is particularly suitable because a single drive arranged in the demolding station, in particular the one that is already present for moving the molded part holders apart and together, is sufficient to deform the molded parts. Since this drive is arranged in a stationary manner and only needs to be present once, it can be dimensioned sufficiently strong without requiring any special effort.

An exemplary embodiment of the invention is explained in more detail below with the aid of schematic drawings:

Fig. 1 is a plan view of a casting machine according to the invention, Fig. 2 is a side view of the casting machine in the direction of

Arrow II in FIG. 1, FIG. 3 shows an enlarged section from FIG. 2, FIG. 4 shows an enlarged section from FIG. 1, and FIG. 5 shows an enlarged section from FIG. 4.

The casting installation shown has a turntable 10 which is mounted on a base frame 12 so as to be rotatable about a central vertical axis A. Arranged within the base frame 12 is a drive (not shown) of the type customary in rotary tables, with which the rotary table 10 can be rotated step by step by 45 °. At the radially outer edge of the turntable 10, eight pivot bearings 14 are arranged at regular circumferential intervals, each defining a horizontal axis B which is tangential with respect to the turntable. A first molded part holder 16 is mounted on each of the swivel bearings 14 in such a way that it can be swiveled outwards from a casting position in which it rests on the rotary table by at least 90 ° into a demolding position. Each first molded part holder 16 is assigned a second molded part holder 18. In the casting position, the molded part holders 16 and 18 are locked together in pairs, as shown in FIG. 1 for seven of a total of eight pairs of molded part holders 16, 18. The eighth pair of molded part holders 16, 18 is shown in FIGS. 1 and 2 in the demolding position and in an exploded state.

In the middle of the turntable 10 there is a container 20 which contains casting slip and can be pressurized. A first mold part 22 is fastened to each of the first mold part holders 16, while a second mold part 24 is fastened to each of the second mold part holders 18. Each pair of casting mold parts 22 and 24 forms a casting mold which, in the example shown, is designed for casting wash basins, as indicated by dashed lines in FIG. 3. For the casting of more complex castings, for example toilet bowls, 22 and 24 casting cores can be arranged between associated casting mold parts. The mold parts 22 and 24 are connected to the container 20 by a hose 26 and 28, respectively.

In addition to the turntable 10, a demolding station 30 is arranged at a point which is reached once by each of the casting molds 22, -24, and has a frame 32 with a shelf 34 in the form of a roller conveyor arranged at the height of the turntable 10. Lateral stands 36 and 38 protrude from the frame 32.

In the casting position and during their pivoting from the casting position into the demolding position, the pair of molded part holders 16 and 18 are locked together in such a way that they keep the associated mold parts 22 and 24 tightly clamped together. For this purpose, four sleeves 40 are fastened to each of the first molded part holders 16, each extending along an axis C parallel to the associated pivot axis B and each guiding a bolt-like first clamping body 42 axially displaceably. The first clamping bodies 42 are aligned with a second clamping body 44, which is also axially displaceably guided in the associated second molded part holder 18. The first clamping body 42 have in the example shown, one threaded bore 46 each, into which a threaded pin 48 formed on the associated second clamping body 44 fits.

The first clamping bodies 42 are prevented from rotating, in the illustrated example by a radial pin 50 which engages in an elongated hole 52 of the associated sleeve 40. Each of the first clamping bodies 42 is prestressed in the direction away from the associated second clamping body 44. For this purpose, a spring 54 is clamped between a spring plate 56 fastened to the relevant first clamping body 42 and the associated first molded part holder 16; in the example shown, the spring 54 is a helical compression spring. The axial freedom of movement of each of the first clamping bodies 42 is limited, on the one hand, by the associated spring plate 56 and, on the other hand, by a locking ring 58, which cooperate with one end face of the associated sleeve 40. The first clamping body 42 can be moved against the resistance of the associated spring 54 in the direction of the associated second clamping body 44. For this purpose, a drive 60 in the form of a pneumatic cylinder, which acts with a piston rod 62 on the spring plate 56 of the associated first clamping body 42, is supported in the demolding station 30 on the first lateral stand 36 for each first clamping body 42.

Each of the second clamping bodies 44 is prestressed in the direction of the associated first clamping body 42. For this purpose, each of the second clamping bodies 44 is assigned a spring 64, in the example shown again a helical compression spring, which is clamped between a support ring 66 fastened to the relevant second clamping body 44 and the associated second molded part holder 18. Each of the second clamping bodies 44 has a hexagon head 68, which normally rests against the back of the second molded part holder 18 under the pretension of the spring 64. In the demolding station 30, four drives 70, for example electric or compressed air motors, are attached to the second lateral stand 38, each one of the are assigned to second clamping bodies 44 and each with a socket wrench 72 matching its hexagon head 68. are equipped.

The first molded part holder 16 is prevented from moving in the direction of the axis B by the swivel bearing 14 of the pair of molded part holders 16 and 18 which are in the demolding station 30 and are pivoted into the demolding position. To move the second molded part holder 18, an essentially plate-shaped support body 74 is provided in the demolding station, which is guided by means of a pair of guide rods 76 which are fastened to it and parallel to the pivot axis B in guides 78 which are fastened to the second lateral stand 38 . A drive 80 in the form of a hydraulic cylinder, the piston rod 82 of which is connected to the support body 74, is also fastened to the second side stand 38. On its side facing the second molded part holder 18, the latter has fastening means 84, for example magnets, which automatically connect it to the second molded holder 18 located in the demolding station 30.

On the frame 32 of the demolding station 30, a lever 86 is pivotally mounted below the shelf 34 about an axis D, which extends parallel to the pivot axis B of the pair of molded part holders 16, 18 in the demolding station 30, and thus also parallel to the axes C. The lever 86, on the free end of which a roller 88 is mounted, can be moved by means of a swivel drive 90, for example in the form of an electric motor, via a self-locking worm gear 92 from the position indicated by broken lines in FIG. 3 to the position shown in full lines and vice versa.

A guide 94 is rigidly connected to each of the first molded part holders 16 and extends approximately radially away from the associated pivot bearing 14, downward when the associated pair of molded part holders 16, 18 are in their casting position occupies, and horizontally, radially to the axis of rotation A when the pair of molded part holders 16, 18 in question takes its demolding position. Each of the guides 94 is fork-shaped, so that when the lever 86 is pivoted in the direction of the axis of rotation A, the roller 88 engages in the guide 94 of the pair of molded part holders 16, 18 which is just in front of the demolding station 30 and still has its pouring position takes. Upon further upward pivoting of the lever 86, a positive connection is created between the roller 88 and the guide 94; this ensures that the pair of molded part holders 16, 18 together with the molded parts 22, 24 attached to them are placed gently on the shelf 34.

When said pair of molded part holders 16, 18 has reached its demolding position in this way, its clamping bodies 42 and 44 are still screwed together, so that the associated mold parts 22 and 24 are still clamped together in the manner required for casting. Now, by extending the drive 80, the support body 44 is placed on the second molded part holder 18. The force exerted by the drive 80 is dimensioned such that the mold parts 22 and 24 are elastically deformed, with the result that the casting formed between them is post-compressed. The elastic deformation of the mold parts 22 and 24 is made possible by the resilience of the springs 64 without the risk that the threads of the threaded bores 46 and threaded pins 48 are damaged.

During the elastic deformation of the mold parts 22 and 24 caused by the drive 80 and lasting only a few seconds or even only a fraction of a second, the second clamping bodies 44 are rotated by means of the drives 70 in such a way that they separate from the first clamping bodies 72. Then the drives 60 are relieved of pressure and the drive 80 is reversed so that the piston rod 82 is retracted. The support body 74 takes the second molded part holder 18 via the magnets 84, so that the molded part 24 from Mold part 22 is moved away. The casting produced between these mold parts 22 and 24 is placed, for example, on a pallet, which is then moved radially away from the turntable on the shelf 34 designed as a roller conveyor.

The molded part holders 16 and 18 are then pushed together again by extending the piston rod 82 of the hydraulic drive 80 and the pneumatic drives 60 are pressurized again so that their piston rods 62 extend and move the first clamping bodies 42 in the direction of the second clamping bodies 44. These are then rotated by their drives 70 in the screwing direction, so that the threaded pins 48 penetrate into the threaded holes 46. The axial forces that occur are limited by the springs 64 in such a way that the screw threads are hardly loaded during screwing in. When the threaded pins 48 have completely penetrated the threaded bores 46, the pneumatic drives 60 are depressurized so that their piston rods 62 retract under the action of built-in return springs, and the hydraulic drive 80 is reversed so that its piston rod 82 has the adhesive force the magnet 84 overcomes and pulls the support body 74 together with the drives 70 attached to it away from the second molded part holder 18. The socket wrench detaches from the hexagon heads 68 of the second clamping bodies 44.

The molded part brackets 16, 18 braced in this way and now exposed together with the mold parts 22 and 24 clamped between them are now pivoted back into the casting position, saving space between adjacent pairs of molded part holders 16, 18 together with the associated mold parts 22, 24 come to stand on the turntable 10. The rotary table is then rotated one step further, and the described demolding cycle is repeated with the next pair of molded part holders 16, 18, while the previously emptied mold 22, 24 is filled with slip via the hoses 26, 28 and this is pressurized.

Claims

claims

1. Casting plant, in particular for die casting ceramic castings, with

a turntable (10) which can be driven in rotation about a central axis of rotation (A),

a plurality of first molded part holders (16) for a first molded part (22) each, which are offset against one another in the circumferential direction on the rotary table (10) and are each pivotable about a tangential pivot axis (B),

- A plurality of second molded part holders (18) for a second mold part (24) each, which can be moved in the direction of an associated first molded part holder (16) and away from it in order to clamp the associated mold parts (22, 24) together or separate from each other, and

- A demolding station (30) with a swivel drive (90) for swiveling back and forth - in each case a first molded part holder (16) between a casting position and a demolding position, thereby ensuring that

molded part holders (16, 18) belonging together in pairs can be pivoted back and forth about their pivot axis (B) between their casting position and their demolding position,

- On the molded part holders (16, 18) together with them about the pivot axis (B) pivotable clamping bodies (42, 44) are arranged, which can be locked and unlocked in pairs by external actuation, and

- In the demolding station (30) drives (60, 70, 80) for actuating the clamping body (42, 44) and for moving apart and together a pair in the demolding position pivoted molded part holders (16, 18) are arranged.

2. Casting plant according to claim 1, characterized in that the paired molded part holders (16, 18) in the demolding position can be moved apart and moved together parallel to their pivot axis (B).

3. Casting plant according to claim 2, characterized in that the clamping bodies (42, 44) are aligned in pairs along an axis (C) parallel to the pivot axis (B).

4. Casting plant according to claim 3, characterized in that the clamping bodies (42, 44) are screw bodies.

5. Casting plant according to claim 3 or 4, characterized in that a first (42) of two associated clamping bodies (42, 44) limited axially displaceable on the associated Formteil¬ holder (16) and in the direction of the second clamping body (44) is biased away.

6. Casting plant according to claim 5, characterized in that the second (44) of two associated clamping bodies (42, 44) is also axially displaceable to a limited extent on the associated molded part holder (18), but towards the first clamping body (42) is biased.

7. Casting plant according to claim 5 or 6, characterized in that in the demolding station (30) for each first clamping body (42) of each clamping body pair (42, 44), a drive (60) for axially displacing the first clamping body (42) in the direction of associated second clamping body (44) is arranged.

8. Casting plant according to one of claims 1 to 7, characterized g e k e n n z e i c h n e t that

- The first (16) of two associated molded part holders (16, 18) is firmly connected to a guide (94) which extends at least approximately radially away from the associated pivot axis (B), and

- The swivel drive (90) in the demolding station (30) drives a lever (86) which is pivotable about a pivot axis (B) of the pair of molded part holders (16, 18) parallel axis (D) such that it can be pivoted into the Guide (90) of the first molded part holder (16) engages and the pair of molded part holders (16, 18) pivots from the casting position into the demolding position.

9. Casting plant according to one of claims 1 to 8, characterized in that in the demolding station (30) a support body (74) parallel to the pivot axis (B) of the first molded part holder (16) there arranged to move back and forth and for engaging is formed on the associated second molded part holder (18).

10. A method for casting ceramic castings from slip, in particular on a casting installation according to one of claims 1 to 9, characterized in that associated mold parts (22, 24) each towards the end of a casting cycle after they have been emptied of excess slip, with additional external forces are elastically deformed towards one another and immediately separated from one another.