GB2067940A - Permanent mould casting apparatus - Google Patents

Abstract

Casting apparatus of manufacturing castings from light- metal alloy comprises two movable divided chill moulds (2, 2a) and three stations (A,B,C) of which the two outer stations (A,C) are casting stations and one central station (B) is a working station at which the chill mould parts of each chill mould in turn can be divided, castings can be removed, cores can be inserted, and the chill mould parts can be closed again. Frame members (13-15) at the working station (B) incorporate hydraulic piston-cylinder units carrying actuating members operable to open and close the moulds. Similarly, at the working station (B) a mechanism mounted below the level of a carriage (6) on which a respective mould is mounted, becomes automatically coupled and decoupled with a casting ejector as the carriage arrives at and departs from, respectively, the working station (B). <IMAGE>

Description

SPECIFICATION Casting apparatus The invention relates to casting apparatus for manufacturing castings from light-metal alloy by means of permanent moulds (chill moulds). It is particularly concerned with the manufacture of cylinder heads for internal combustion engines, using divided chill moulds, movement of the chill mould parts and of a device for ejecting the casting being effected by mechanisms operated by a pressure medium; and supply devices, for example for heating, cooling and the like, being provided for the mould.

Chill mould casting for manufacturing workpieces of light metal is carried out in various ways. In the manufacture of light-metai cylinder heads there are used chill moulds which are divided in their longitudinal plane and the parts of which are so mounted as to be displaceable for the purpose of closing and opening the mould. For this purpose, hydraulically operated actuating members are frequently used which are connected to the chill mould parts. In addition, actuating members for ejecting the castings are connected to the mould and where a stationary arrangement of the chill mould casting apparatus is used, ejection of the products per unit of time is relatively low.

It is known for the manufacture of light-metal cylinder heads to take place in a circulating system, wherein there is employed a turnstile on which the moulds move in a circle. In this case, the chill mould parts of each divided mould are also directly connected to the hydraulic actuating members for displacing these parts, and also the parts for operating a device for ejecting the castings are connected to the circulating mould.

The same applies to ducts for supplying to the mould liquid for heating ar cooling the chill mould parts, there ducts leading to a column centrally mounted within the turnstile with corresponding rotatable connections. In such a circulating system for chill casting, as in the case of a stationary installation, each mould is provided with varied actuating members with associated connecting parts and with the parts of the liquid supply arrangement, provision having to be made for the displaceability of the chill mould parts in each case. The provision of all the necessary actuating members and so on for each individual chill mould increases not only the size, the volume and the space requirement of the moulds considerably, but also the cost of manufacturing the moulds, the cost of installation and also the cost of operation, as considerable masses have to be moved.In order to operate rationally, by necessity forced cooling of each mould so as to prepare it in good time for the next casting in the circulating system cannot be dispensed with, which complicates the manufacture and the operation of the moulds and also increases costs.

It is further known when manufacturing castings from grey cast iron to run moulds through a plurality of working stations and thereafter to bring the finished casting of grey cast iron, by means of a crane-like device, to another plane on which the casting can slowly cool down by itself.

Such a method of operation and such a form of construction of the apparatus is unsuitable for the manufacture of light-metal castings.

According to the present invention there is provided casting apparatus for manufacturing castings from light-metal alloy by means of divided chill moulds, the apparatus comprising two movable divided chill moulds and three stations of which two stations are casting stations and one station is a working station at which the chill mould parts of each chill mould in turn can be divided, casting can be removed, cores can be inserted, and the chill mould parts can be closed again; this working station being the central station of the three stations and the casting stations being the two outer stations.This apparatus enables castings to be cast from a light-metal alloy by means of permanent moulds in a manner which brings about a simplification of the installation by way of economizing on functional elements; brings about operationally reliable implementation of the processes For preparing the moulds for casting; and also brings about a considerable increase in production. Such a construction of the apparatus for manufacturing castings from light metal in a chill mould casting technique affords substantial advantages in respect od installation, size and costs, operating reliability and production.

Continuous operation can be carried out with the smallest possible number of chill moulds, one casting process being associated with each cycle; long displacement paths from the station for preparing the chill mould for casting to the one or other casting station are not necessary. The chill mould with the chill mould parts pulled apart can be employed from two sides. there being free access on both sides of the apparatus. The time required by the chill mould from filling until the casting is removed is sufficient for removing the casting and for preparing the chill mould for the next casting operation, with the result that one working station suffices to perform these operations. If necessary, the central station can be provided with two working stations arranged in series, without influencing appreciably the course of operation in respect of cycle time.The entire apparatus is made simple and easily understandable by the fact that the danger of any sources of distrubance and error arising when the casting installation is in operation is substantially reduced. For the casting apparatus as a whole, there is a high level of production in relation to the size of the total installation and in relation to the space requirement. Production can be multiplied using simple means. Due to the smail space requirement, several devices can be arranged in series. In this case, there is extraordinarily advantageous utilization of space and volume.

Advantageously, each chill mould of an installation has a casting-on part with a filling hopper at its front face remote from the working station. a casting metering furnace preferably being arranged in an extension of the direction of movement of the chill moulds. The working station thereby comes to iie at a relatively long distance away from the casting iocations of the casting stations, which means that, from a safety point of view, operations at the working station can be carried out virtually undisturbed by the casting operations at the casting stations. When several apparatus are arranged in series, a casting metering furnace can be provided so as to be movable at right angles to the direction of movement of the chill moulds, so that one casting metering furnace can be used for several casting stations of difsrent apparatus.

Dispacement of the two chill moulds of an apparatus preferably takes place along rails which run from casting station to casting station and, in this case, the two chill moulds can be kept interconnected by a spacing member.

According to a further feature of the invention hydraulic actuating members for opening and closing the chill mould parts and also for ejecting the casting from the bottom portion of the chill mould from stationary component parts of the working station. As a result, the design of the chill moulds is simple and this represents a considerable saving in costs and operation. There are substantial savings in apparatus parts and tools. The displaceable chill mould parts are completely free from the hydraulic mechanism for operation. The stationary hydraulic installations, likewise for the ejecting device for ejecting the casting from the opened chill mould, are at all times accessible because of their stationary arrangement and can be easily checked. Certain disturbances can be eliminated immediately without hating to interrupt operation.The chill moulds can be relatively light in weight. A relatively low level of kinetic energy is required by the displacement of the chill mould parts. The occurrence of sources of disturbance is greatly reduced.

The invention further provides for the chill mould parts of a longitudinally divided chill mould to be arranged on a common base plate so as to be transversely dispiaceable in guideways, and for the base plate to be mounted on a movable plate by means of centering supports. Such a design allows above all the chill mould to be readily exchanged from the movable carriage, so that in the event of any disturbances, any chill mould in use can be replaced by a fresh one.

Advantageously, the chill mould parts interengage with stationary actuating members for opening and closing the mould and for raising and lowering the ejecting device by means of, for example, hook-shaped portions which afford one another free passage in the direction of movement of the permanent mould. This thereby ensures that the chill mould parts interengage with the stationary actuating members in a simple and operationally reliable manner.

For a better understanding of the invention and to show how the sam may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a diagrammatic side view of apparatus for casting internal combustion engine cylinder heads from light metal by means of permanent moulds, Figure 2 is a diagrammatic cross section, on a larger scale, of a working station of-the apparatus of Figure 1, taken on line Il-Il in Figure 1, and Figure 3 is a schematic representation on a still larger scale of a cross section of the apparatus.

The apparatus 1 shown in the Figures includes permanent moulds (chill moulds) 2, 2a each divided in its longitudinal centre plane into chill mould parts mounted on a base plate 5 so as to be displaceable in a transverse direction. The base plate 5 is supported by an underframe G;Nhich 6 which can be moved on rails 7. The apparatus further includes three stations A, B and C, the outer stations A and C being casting stations, and the central station B being a working station at which the chill mould parts are separated, castings are removed, cores are inserted, and the chill mould parts ere closed again. In the particular apparatus illustrated there are associated with these three stations A, B and C two movable chill moulds 2 and 2a.

A substructure 8 of the rails 7 bears on longitudinally extending carriers 9 supported by transversely running base supports 10. Buffer posts 11 and 12 are provided at the ends of the tracks.

The working station B has fixed perpsndicular supports 13, 14 connected by horizontal carriers 1 5.

Each chill mould 2, 2a has on its face remote from the working station B, that is, on the faces of the two moulds which are remote from one another, a casting-on portion 16, 1 6a that includes a filling hopper. In this way at the casting stations A and C the respective casting locations are disposed as far as possible from the working station B. Advantageously, casting metering furnaces 17, 1 7a with which the filling hoppers co-operate are disposed in an extension of the direction of movement of the chill moulds.

In operation, while, for example, the chill mould 2a is disposed in the casting station A, the other chill mould 2 is disposed in the working station B in which the casting is removed after the chill mould parts 3 and 4 have been opened. There then follows insertion of the different cores on a fixed bottom portion of the mould. The chill mould parts are then closed, after which a top core is inserted in the mould. The chill mould 2 thereby prepared at the working station B is then conveyed into the casting station C, whereupon the filled chill mould 2a is moved from the casting station A into the working station B. The chill mould 2 is now filled with light metal at the casting station C from the casting metering furnace 1 7. During the filling process, and also during a predetermined period thereafter, the chill mould 2 remains at the casting station C. During this time the chill mould 2a at the working station B is freed from its casting and is prepared to perform a further casting operation. As soon as the operations at the working station B are completed, the chill mould 2a is conveyed back to the casting station A. At the same time the chill mould 2 located in the casting station C can be conveyed back to the working station B. Casting now takes place at the casting station A whilst, at the working station B, after the casting is removed, the chill mould 2 is prepared for a fresh casting operation. These operating phases with the two chill moulds 2 and 2a and the three casting stations A, B and C can then be repeated in a continuous shuttle.

In order that the underframes 6 of the two chill moulds 2 and 2a remain at a specific distance from one another, the underframes are fixedly interconnected by a spacing member 6a.

Displacement of the chill moulds with the undercarriages can be carried out by hand pressure exerted on a crosspiece of the underframe carriage. However, it is also possible to provide the underframe with a drive motor which is switched on and off in the corresponding cycle, and displaces the underframe in the appropriate direction.

In place of the rails 7, 8 a roller conveyor can be used in which the rollers are driven in one or the other direction of rotation. In this case the underframe 6 can bear directly on the roller conveyor.

The permanent mould with base plate and underframe actuating device for the displaceable chill mould parts and the ejecting device will now be described with reference to Figures 2 and 3.

The underframe 6 is displaceable by means of travelling wheels 20 along the rails 7. The base plate 5 is provided with centering supports 21 which engage over projecting bolt-like portions 22 which are connected to the underframe 6. The base plate 5 is thereby exchangeable, along with the permanent mould 2, on the underframe 6 and thereby a base plate provided with a different type of chill mould can be readily mounted with accurate centering in respect of the underframe 6 and hence the rail track 7, 8 once a first base plate has been removed. This possibility of exchange is of use not only in a case where a permanent mould is damaged, but also so that permanent moulds of different sizes and types can be used on the same conveying devices.

As has been stated, the permanent moulds 2, 2a include chill mould parts 3, 4 divided in the longitudinal center plane, which are opened to remove the casting by displacement in a transverse direction and which must be closed again for the casting process. The displaceable chill mould parts 3, 4 are slidably mounted on the common base plate 5 in guideways 23. For this purpose, the chill mould parts bear on slide rails 24 (Figure 1) and are guided on a central centering ridge 26 by means of projections 25 mounted on the chill mould parts. Further ridges 27 are provided on the base plate 5 at the ends of the transverse sides of the chill mould parts 3, 4.

In this way, safe, accurate and reliable displacement movement of the two chill mould parts from and towards one another is ensured without any danger of tilting.

For displacing the chill mould parts 3 and 4 for the purpose of opening and closing the permanent mould, actuating members, for example hydraulically driven, are fixedly arranged on both sides of the working station B. These members include piston cylinder units 30, 31 disposed on the supports 13, 14 respectively, thereby being provided on their piston rods 32, 33 at their free ends hook-shaped portions 34, 35, in the recesses 34a, 35a of which there engage projections 36, 37 which are fixedly connected to the chill mould parts 3, 4. In addition, there are provided on the chill mould parts 3, 4 stop portions 37, 39 against which there come to bear the front faces of the hook-shaped portions 34, 35 for pushing together the chill mould parts 3, 4.The recesses 34a, 35a are so provided on the hook-shaped portions 34, 34 that the hook-shaped portions 34, 35 and the projections 36, 37 afford one another free passage in the direction of movement of the permanent mould. When the permanent mould is run into the working station B, the projections 36, 37 of the chill mould parts automatically enter the recesses 34a, 35a of the hook-shaped portions 34, 35. Thereafter, the chill mould parts 3 and 4 can be opened and closed by means of a pulling or pushing movement of the lifting piston/cylinder units 30, 31. The chill mould parts remain free from the hydraulic actuating mechanism; so that they can be of extremely simple design in respect of the execution of the displacement movements.

The hooked interengagement of the parts can also be effected in such a way that the chill mould parts can be provided each with a hooked portion.

The stop portions 38, 39 can serve at the same time to come to bear against correspondingly arranged slide bars in the path of the permanent mould to the castingstations A and C and also at the casting station B, which slide bars are so arranged and guided that the chill mould parts are held pressed together between the slide bars.

A corresponding arrangement in respect of the fixed mounting of the hydraulic actuating members is also provided for the ejecting device 41. This device includes a lifting beam 42 which is slidably mounted on rods 43 secured to the base plate 5. Fixedly connected to the lifting beam 42 is a shaft 44 which is provided (below and remote from the beam 42) with a flange portion 44a and which freely projects through an aperture 45 in the underframe 6. A fixedly arranged hydraulic lifting cylinder 46 has a piston rod 47 to which there is fixedly connected a double-hook portion 48, the hook ends of which engage over the flange portion 44a of the suspended shaft 44. The hook portion 48 is additionally guided by means of a shoulder 49 on a pin 50.As soon as the chill mould parts 3 and 4 are pulled apart by means of the fixed piston/cylinder units 30, 31 and the casting is thereby freed, the fixed ejection cylinder 46 becomes operative. The base of the hook portion 48 encounters the suspended shaft 44 and drives the latter, and hence the push rods 51 mounted on the beam 42, upwards, whereby the casting is lifted from the bottom portion 52 of the permanent mould. In the lifted state the casting can be removed from the opened permanent mould by means of, for example a tong device.

Thereafter the lifting cylinder 46 is set in operation again. By means of the hook portion 48 engaging with the flange portion 44a of the shaft 44, the front faces of the push rods 51 are aligned with the surface of the bottom portion 52 of the chill mould.

For arresting the underframe 6 receiving the permanent mould with the base plate 5 there is employed a device 54 as retaining device. This device includes a piston/cylinder unit 55 at each side pivotally mounted at 56 on a stationary block 57. The piston 58 has a fish plate 59 which hingedly engages a double-armed lever 60 by way of a pin 61, the lever 60 pivoting about an axis 62.

The levers 60 act on extensions 63 of the base plate 5. In the stopping position of the chill moulds with the underframe 6 in the station B, the underframe is thus arrested by being pressed down onto the rails 7 or onto the roller conveyor.

Claims (9)

1. Casting apparatus for manufacturing castings from light-metal alloy by means of divided chill moulds, the apparatus comprising two movable divided chill moulds and three stations of which two stations are casting stations and one station is a working station at which the chill mould parts of each chill mould in turn can be divided, castings can be removed, cores can be inserted, and the chill mould parts can be closed again; this working station being the central station of the three stations and the casting stations being the two outer stations.

2. Apparatus as claimed in claim 1, wherein each chill mould has casting-on portions, including filling hoppers, on a face remote from the central working station, that is, on the faces of the two chill moulds which are remote from one another; and wherein casting metering furnaces with which the filling hoppers co-operate are arranged in an extension of the direction of movement of the chill moulds.

3. Apparatus as claimed in claim 1 or 2, wherein the two chill moulds and an underframe for each are interconnected by a spacing member, and wherein both chill moulds are movable together along the rails which extend from casting station to casting station.

4. Apparatus as claimed in claim 1, 2 or 3, wherein the central station is divided into two working stations.

5. Apparatus as claimed in any one of the preceding claims, wherein hydraulic actuating members for opening and closing the chill mould parts and for ejecting castings from the bottom portion of the chill mould form stationary component parts of the working station.

6. Apparatus as claimed in any one of the preceding claims, wherein the chill mould parts of each longitudinally divided chill mould are arranged so as to be transversely displaceable on a common base plate in guideways; and wherein this base plate is mounted by means of centering supports on an underframe in such a way that it can be removed.

7. Apparatus as claimed in any one of the preceding claims wherein the chill mould parts interengage with stationary actuating members fo opening and closing the mould and for raising and lowering an ejecting device by means of hookshaped portions which afford one another free passage in the direction of travel of the mould.

8. A plurality of apparatus as claimed in any one of the preceding claims, arranged in series and associated with casting metering furnaces that are movable at right angles to the direction of movement of the chill moulds of each apparatus.

9. Casting apparatus for manufacturing castings from light-alloy by means of divided chill moulds, substantially as hereinbefore described with reference to the accompanying drawings.