WO1997024200A1

WO1997024200A1 - Method and equipment for controlling the movements of a casting ladle with a short pouring height in a foundry

Info

Publication number: WO1997024200A1
Application number: PCT/CH1996/000455
Authority: WO
Inventors: Fritz Lauper
Original assignee: Fritz Lauper
Priority date: 1995-12-29
Filing date: 1996-12-20
Publication date: 1997-07-10

Abstract

In the equipment proposed, the ladle-tipping device (1) is designed so that, using two cams (9 and 10), the theoretical point of rotation (S1) at the lip of the ladle can be lowered towards the mould (25) and displaced to a point (S2) nearer the centre of the mould. This gives a pouring height lower than that previously obtainable in an automatic casting process.

Description

Method and device for controlling the movement of a ladle with low

Pouring height in a casting plant

The present invention relates to a method for controlling the movement of a ladle according to the preamble of patent claim 1 and a device for carrying out the method according to the preamble of patent claim 3.

Existing automatic pouring systems for repeated, controlled filling of liquid metals from a tiltable pan into molds which are fed in succession function as follows: the melt runs out of the pan during casting via a snout stone with the radius R, the tilting axis of the pan being at least approximately through the The center of this radius runs in such a way that, regardless of the tilting angle of the pan, approximately the same geometric and thus fluidic conditions are achieved. Tilting takes place via a regulated drive, which engages the pan via mechanical connecting links.

With such systems, the casting process runs smoothly during casting, during casting and when it is finished. On the other hand, such systems have the disadvantage that, in order to cast with a relatively low pouring height, the pouring funnel must lie near the edge of the molding box. In the case of pouring funnels lying further inwards and if a certain safety distance of the ladle body from the mold box is maintained, the pouring height increases due to the segment shape of the pouring ladle.

Since pouring funnels located far inside the molding box cannot be reached sufficiently, the funnel must be pulled to the edge, which leads to expensive changes in existing models. In the case of molded boxes with weighting irons, the weighting irons often have to be modified, which in turn causes additional costs. However, because changes cannot always be made to the models or weighting iron, due to the high pouring height, it is only possible to pour with an extended pouring spout. Such a casting However, schnauze is not suitable for automatic casting and is difficult to handle with manual casting.

A casting method has become known from EP-PS 592 365, in which the casting ladle can be displaced further towards the center of the casting mold after the first casting operation while maintaining a certain safety distance between the pan body and the molding box with the aid of a fixed tilting axis. In this method, the fixed tilting axis with the lifting drive is attached to the front of the pouring spout, and since the tilting bearing required on the tilting axis must also be at a safety distance above the molding box or the weighting iron, this also leads to a high pouring height in terms of design. However, a high pouring height entails significant disadvantages: since more kinetic energy has to be destroyed, a deeper pouring funnel is necessary so that the top box is not optimally used. Furthermore, more circulation material is required, there are more injection irons, a less smooth pouring with more turbulence in the funnel, more sand flushing and more sand and gas inclusions in the casting are to be expected. With molded boxes with weighting iron, the pouring height is increased because the tilting bearing must lie above the weighting iron.

The object of the invention is now to avoid all the disadvantages mentioned and to provide a method for controlling the movement of a pouring ladle, in which pouring can always be carried out at a low pouring height, even with pouring hoppers lying far inside the molding box. This object is now achieved by the method according to the invention, which has the method features listed in the characterizing part of patent claim 1. Advantageous further developments of the subject matter of the invention are listed in claims 2 to 9.

An exemplary embodiment of the invention is explained in more detail below with the aid of the purely schematic drawing. Show it:

1 shows the tilting device in a view of a casting mold path, partly in section, FIG. 2 shows the tilting device from FIG. 1 with a filled ladle in a side view, partly in section, Fig. 3 shows the tilting device of Fig. 2 immediately before the start of casting and

4 shows the tilting device from FIG. 2 after the end of the casting in the uppermost tilting position.

The tipping device 1 can be moved parallel to a casting mold web 6 on wheels 2 of a longitudinal carriage 3 and on rudder 4 of a transverse carriage 5. On each side of the pouring ladle 7 to be tilted, two superstructures 8 are attached to the transverse carriage 5, each of which has a control curve 9 and 10. The ladle 7 is supported by a holding frame 11 which has a support tube 12 which is guided with a main roller 13 in each cam 9. To hold the ladle 7, two support arms 14 and 15 are attached to the support tube 12. In addition, the support tube 12 is guided in each control cam 10 by a swivel roller 17 fastened to a swivel arm 16. A lifting drive 18 drives a sprocket 20 via a drive shaft 19. A pull chain 22 is fastened to each of an extension 21 of the support tube 12 and is guided to the chain wheel 20 via a deflection roller 23 attached to the end of the structure 8. With one revolution of the sprocket 20, the ladle 7 is raised from the lowest to the highest position, the main roles 13 and. the castors 17 in the control curve 9, respectively. 10 are performed.

Before casting, the casting ladle 7 filled with melt 24 is taken over by a rotating device (not shown) and moved with the transverse carriage 5 against the casting mold web 6 and opposite a casting mold 25 transported with the casting mold web 6 with a casting funnel 26 which is loaded with a weighting iron 27 is stopped. Because the tilting device 1 can also be displaced parallel to the mold path, it is therefore not absolutely necessary to cast in time with the feed speed of the mold path. The lower section with the theoretical ladle insertion radius R2 of the control curve 10 is used for transferring and taking over the casting ladle from the turning device and for the horizontal movement. The middle section 28 between the lower section with the radius R2 and the upper section with the radius R3 of the control curve 10 is designed in such a way that the support tube 12 with the support arms 14 and 15 is pivoted about a certain angle, indicated by a double arrow 29, around the center point M, such that the theoretical snout pivot point S1 with the casting ladle inserted becomes the theoretical snout pivot point S2 during casting changes (Fig. 3), whereby a very low pouring height 30 is obtained and the pouring funnel 26th can also be arranged in the mold center. From now on, during casting, the theoretical turning radius R1 of the pan, the theoretical pan insertion radius R2, the inner radius R3 of the control cams 9 and 10 and the snout radius R4 rotate around the theoretical snout pivot point S2. While the swivel roller 17 passes through the upper section of the control curve 10 with the inner radius R3, which coincides with the inner radius R3 of the control curve 9, the situation mentioned remains intact during the entire tilting process until the ladle is empty (FIG. 4 ), the surface of the melt also remaining constant due to the turning radius' R1 of the ladle. The control curves 9 and 10 could even be arranged such that the theoretical snout pivot point S2 would lie within the weighting iron or even within the casting mold during lowering and displacement.

The muzzle of the ladle is equipped with an interchangeable snout stone 31. In this way, the stone can be kept smaller and cheaper, it can be replaced quickly and easily when changing pans, and refractory material is saved. The exact insertion of the snout stone is brought about by a holder mounted in the snout, so that the radius R4 of the snout stone moves exactly around the theoretical snout pivot point S2 during casting, thus avoiding a pouring jet migration during the entire tipping process.

To hold back the slag, to break the waves and to destroy the kinetic energy generated in the pan by tilting, a specially shaped slag stone 32 is used in the vicinity of the snout stone 31.

The tilting device can also be equipped with weighing cells 33, as a result of which the casting process can be switched off automatically by means of a weighing system depending on the melt weight.

Claims

claims

1. Method for controlling the movement of a ladle with a lifting device, which ladle is tilted by means of a control curve around a theoretical turning point, characterized in that, for casting with a low pouring height, the theoretical turning point is lowered against the mold box before the start of pouring and is shifted towards its center.

2. The method according to claim 1, characterized in that the control curve controlling the tilting movement is superimposed on a further control curve controlling the lowering and shifting of the theoretical snout pivot point.

3. Device for carrying out the method according to claim 1 or 2, with a Haltge¬ stell (11) for the casting ladle (7), a lifting device (18) for tilting the pan and each with a control curve (9) for controlling the tilting movement, characterized in that a further control curve (10) is arranged on each control curve (9).

4. The device according to claim 3, characterized in that the holding frame (11) comprises a support tube (12) with two support arms (14 and 15) for the ladle (7), and that at each end of the support tube (12) a main roller (13) in the cam (9) and a swivel arm (16) a swivel roller (17) is guided in the other cam (10).

5. The device according to claim 3 or 4, characterized in that the further control curve (10) comprises a lower section with the radius R2 and an upper section with the radius R3, while the central section (28) is designed such that the theoretical snout pivot point S1 is shifted to S2 by the control.

6. Device according to one of claims 3 to 5, characterized in that the lifting device (18) comprises two pull chains (22) fastened to extensions (21) of the support tube (12), which via deflection rollers (23) and chain wheels (20 ) are performed.

7. Device according to one of claims 3 to 6, characterized in that the pouring pan (7) is equipped with an interchangeable snout stone (31).

8. Device according to one of claims 3 to 7, characterized in that the pouring pan (7) in the vicinity of the muzzle stone (31) is provided with a slag stone (32).

9. Device according to one of claims 3 to 8, characterized in that weighing cells (33) are arranged for determining the weight of the melt.