GB2056341A - Casting apparatus - Google Patents

Abstract

Casting apparatus for manufacturing castings from light- metal alloy by means of moulds in an endless circulating system is disclosed, wherein each mould has mould parts (3, 4) separable from one another mounted on endless travelling conveying device (7); wherein hydraulic actuating members (59, 60, 75) for moving the mould parts for opening and closing the mould and for ejecting a casting from the bottom portion of the mould are disposed at respective working stations (I-VI) and form stationary component parts of an underframe or frame (8) of the conveying device; and wherein there is associated with a section of the conveying device which is free from the working stations a hood-like cover (28) which is closed on at least three sides and which serves as a heating or exhausting device for the closed moulds. <IMAGE>

Description

SPECIFICATION Casting apparatus This invention relates to casting apparatus for manufacturing castings from light-metal alloy by means of permanent moulds (chill moulds) in an endless circulating system. It is particularly concerned with the manufacture of cylinder heads for internal combustion engines in divided moulds, the parts of which are opened and closed by appropriate mechanisms.

Different forms of apparatus for chill casting workpieces consisting of light metal are known. In the manufacture of light-metal 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, there are required power-operated, generally hydraulically operated, actuating members, to which the parts of the mould are connected. In addition, where the apparatus is stationarily mounted, supply ducts (for example for heating-up the mould) and actuating members for ejecting the casings are connected to the mould in order to provide a unit which is as compact as possible, while avoiding sources of error as far as possible.In the case of moulding internal combustion engine cylinder heads, there are also provided for forming admission and exhaust passages in the cylinder head, steel quills which are also hydraulically actuated and form a component part of the displaceable mould parts.

In the case of the stationary arrangement of the apparatus, ejection of the castings per unit time is, of course, relatively low.

The procedure has therefore already been adopted of manfacturing light-metal cylinder heads by a casting apparatus incorporating an endless circulating system, wherein there is employed a turnstile on which the moulds are moved in a circle. In this case, the parts of each divided mould are also directly connected to the hydraulic actuating members for displacing them, and likewise the parts for operating a device for ejecting the casting are connected to the circulating mould. The same applies to ducts for supplying to the mould liquid for heating or cooling the mould parts, and to actuating members for introducing and withdrawing the steel quills for the formation of the admission and exhaust passages in the cylinder head. The ducts lead 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 at the same time for displaceability of the mould parts in each case.

The provision of such individual equipment on each chill mould with all the necessary actuating members and so on not only considerably increases the cost of manufacture of the moulds, but also involves the danger of creating a large number of sources of error in the operation of the casting apparatus. Moreover, the turnstile arrangement limits the possibility of structural expansion and enlargement, because the installation is then subject to considerable operational limitations and becomes structurally uneconomic. The size of the installation is limited to about six to eight moulds.In order to be able to operate rationally in such cases, it is necessary to sacrifice the possibility of avoiding forced cooling of each mould to enable each mould to-be made available in good time for the next casting operation in the rotary system, and this further increases the cost of manufacture of the moulds.

It is further known for producing castings of grey cast iron to run moulds reciprocally along an extended path between working stations, which are provided at various points along the path of reciprocation, 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. Such a procedure and such a form of construction of the casting 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 moulds in an endless circulating system, wherein each mould has mould parts separable from one another mounted on an endless travelling conveying device; wherein hydraulic actuating members for moving the mould parts for opening and closing the mould and for ejecting a casting from the bottom portion of the mould are disposed at respective working stations and form stationary component parts of an underframe or frame of the conveying device; and wherein there is associated with a section of the conveying device which is free from the working stations a hood-like cover which is closed on at least three sides and which serves as a heating or exhausting device for the closed moulds.This apparatus enables light-metal castings to be manufactured by means of permanent moulds in an endless circulating system, which renders possible a substantial reduction in the cost of the installation and savings in component elements and tools, a reliable operation of the circulating system and a considerable increase in output.

The present formation of the circulating system of the apparatus for casting iight-metal castings, more especially for casting cylinder heads of internal combustion engines, affords a substantial reduction in the number of equipment parts and tools for the rotary system. With substantially any number of moulds, these parts, and more particularly the displaceable mould parts, are completely free from the hydraulic mechanism for their actuation. In addition, the hydraulic actuating mechanism is required only at two points, that is to say, at the mould parts separating station and at the mould parts closing station. This represents a considerable reduction in the number of tools and devices for the mechanism for the actuation of the mould parts. The same applies also to the device for ejecting the casting from the open mould.

The hydraulic installations are available at any time during the operation of the circulating system and can readily be monitored. Any disturbances can thus be readily rectified without the operation having to be interrupted. The moulds themselves are of simplified construction, which results in a considerable reduction in the cost of production and operation. The sources of disturbance are greatly diminished. The simplification in the construction of the apparatus facilitates the provision of the hood-like cover, closed on at least three sides, in the path of travel of the closed mould towards the casting station until it reaches the station at which the mould parts are separated. Such a cover is useful for a number of purposes.The cover may be readily used as a heating device for heating all the moulds during the operation of the circulating system, by providing the cover with heating devices situated at intervals over its entire length, which serve for preheating the moulds. This renders unnecessary the use of heating devices which are situated directly at the mould parts and which would have to be provided with co-rotating supply connections.

This further results in a substantial reduction in cost of the whole apparatus. During continuous operation of the apparatus, the cover may serve as an air extraction device for the moulds containing the light-metal castings. For this purpose, appropriate air extraction devices, for example fans or the like, are provided at intervals along the length of the cover for continuously extracting the gases formed. At the same time, this exhausting affords a natural ventilation of the moulds with the castings, so that they do not have to be individually cooled. In this case, the timing of the operation of the circulating system may be made such that the necessary time during which each casting must remain in its mould is reached at the extraction station.The features mentioned in the foregoing combine to give increased economy of the whole casting operation with s substantial reduction in the cost of the apparatus and a saving of high tool costs, as well as a reliably operating circulating system with a substantial increase in the rate of product production.

For a better understanding of the invention, and to show how the same 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 casting apparatus for the manfacture of cylinder head castings from light metal by means of permanent moulds which move in a vertical plane, Figure 2 is a diagrammatic cross-section along the line Il-Il of Figure 1, of a lifting device for the moulds, Figure 3 is a diagrammatic cross-section along the line Ill-Ill of Figure 1, of a station at which mould parts are separated, Figure 4 is a diagrammatic cross-sectional view, drawn to a larger scale, of a mould with underframe, and a conveying device with the mould mounted thereon, shown in a closed condition of the mould parts.

Figure 5 is a diagrammatic cross-sectional view of a base plate, the mould and cores as shown in Figure 4, drawn to a larger scale, Figure 6 is a diagrammatic longitudinal section through the mould with the base plate, Figure 7 illustrates diagrammatically in plan view a further form of casting apparatus for the manufacture of cylinder head castings from light metal by means of permanent moulds which move in a horizontal plane, and Figure 8 is a diagrammatic fragmentary plane view of an apron conveyor device for transporting the moulds of the apparatus of Figure 7.

In the casting apparatus 1, shown in Figures 1 to 6, which is for the manufacture of light-metal castings by means of permanent moulds (chill moulds) in a circulating system, more particularly for casting cylinder heads of internal combustion engines, there are provided permanent moulds 2 each divided in its longitudinal centre plane into chill mould parts 3 and 4 displaceably mounted on a base plate 5 (Figure 5). The moulds 2 with their base plates 5 and underframes 6 are moved along an endless conveyor 7 running in a vertical plane, the movement taking place either in a predetermined rhythm of continuously.For this purpose, there is employed a frame 8 in which there are provided lower longitudinally extending girders 9 with cross-pieces 10, upper longitudinally extending girders 11 with crosspieces 12, vertical posts 13 at one end and vertically posts 14 at the other end, the whole forming a quadrilateral frame. At the head end of the direction of travel of the moulds, there is situated a lifting device 1 5, while at the other end of the frame there is provided a lowering device 16. The lifting and lowering devices 1 5 and 16 are of like construction, each including guide columns 17 and 18 on one or both sides of the frame 8, on which there is provided a suitable vertical mobile cradle. In the illustrated example, the cradle consists of bent-over support arms 19 on to which the mould with the whole underframe can be pushed.The support arms 1 9 are secured to slides 20 which, in each of the devices, can be moved upwards and downwards along the columns, for example by means of chains and a wind-on device, the latter being driven by a motor.

In the lower part of the frame 8 are situated working stations I to VI. At the station I the mould parts 3 and 4 are separated from one another and the casting is extracted by means of an appropriately constructed tongs device. At the same time, cleaning of the open mould can also be effected. At the stations Il and Ill, the various cores are inserted in position, for example (Figure 5) a base core 26 on the bottom part of the mould, and sand cores for the formation of the admission and exhaust passages. Thereafter, station IV serves as an idle station at which no operation is intended to take place but at which the travel cycle of the moulds can be evened-out in the event of disturbances.At the station V, the mould parts 3, 4 can be reclosed by means of hydraulic actuating members fixedly located laterally beside the track, it also being possible for the top core to be inserted into the closed mould in this station. The station VI is the terminal station of the lower part of the endless track. This station VI constitutes at the same time the casting station, it being possible for casting to be effected by means of a controlled-feed furnace 27. The casting device is situated at the head end of the lower part of the endless track. The casting station VI is at the same time the bottom station of the lifting device 1 5 by which the closed mould together with the base plate and the underframe is brought to the upper part of the endless frame.

Provided above the stations I to V is the upper part of the endless track for return of the closed moulds. There is disposed on this section between the lifting device 1 5 and the lowering device 1 6 a cover which is at least in the form of a hood, i.e.

closed on three sides, but is preferably a closed tunnel 28 through which the moulds pass on their way to the lowering device. The hood-like cover or tunnel 28 serves for various purposes. For example, during operation in which the moulds are at their operating temperature owing to continuous filling with molten light metal, gases escaping from the filled moulds are caught and discharged. For this purpose, extraction fans may be provided at suitable points above extraction cowls 29 and 30 adjoined by corresponding discharge ducts. The moulds are appropriately ventilated by the suction set up by the extraction fans, whereby the cooling process is accelerated.

At the same time, the circulation path is shortened. The ventilation must be so adjusted that the mould, and hence also the light-metal casting, can be lowered at the end of the tunnel 28 to the separating and extracting station.

Additionally, when the whole system is started, the hood-like covering or tunnel 28 advantageously acts as a means of preheating the moulds to a desired temperature, which may be about 450--5000C. For this purpose, the tunnel 28 or the like may be provided with heating devices 31 situated laterally of the moulds or above them. The length of the tunnel 28 corresponds to the total length of the working station I to V. Any suitable heating device may be used, for example electrical or gas radiation heaters. In this way, heating at the moulds themselves is rendered unnecessary, whereby the construction of the moulds is simplified. The same applies to ventilation of the moulds passing through the tunnel or the like. Cooling means for the mould parts can be omitted, and hence also connections for the coolant.As soon as the moulds have reached the desired operating temperature, the heating is shut off at the covering or tunnel 28. Thereafter, the operation of the installation can be completed, the covering or tunnel being used for the extraction of the gases and for the ventilation of the moulds. The covering or tunnel renders completely unnecessary supply ducts which must otherwise be used for the moulds and, in the apparatus as so far described the space required for the whole installation is reduced to a minimum and a relatively small number of moulds is required in the continuous circulating system. The gases formed in casting and also thereafter are dissipated after casting in a plane which is higher than the working stations, which corresponds substantially to the natural course of events. The working stations remain free from such troublesome impairments.The whole apparatus is thus extremely compact and short, and it is possible to work without hindrance on either side of the working stations. Monitoring of the operation is substantially facilated.

At least one idle station is advantageously provided between the working stations along the lower part of the endless track. In this way, any involuntarv disturbances can readily be rectified in the normal cycle of operations. For example, it is possible to effect at this idle station, if necessary, an exchange of a mould without the time cycle being impaired. In addition, if the casting station is also the bottom station of the lifting device, and the casting device is provided at the head end of the lower part of the circular track, this on the one hand contributes to a ready perceptibility of the performance of the working operations and more particularly of the removal of gas from the moulds with low cost of construction. After completion of casting, the closed mould moves together with the casting to the level of the cover with the exhausting device.On the other hand, the sides of the working stations, up to an including the casting station, remain free from the casting installation. This begins in the axial prolongation of the lower part of the endless track.

In the embodiment illustrated in Figure 1 there is provided for running the moulds together with their underframes 6 a roller track 33, the rollers of which can be driven section-wise in accordance with the lengths of the stations, this being done by means of the time cycle set in each instance.

Alternatively the rollers of the roller track 33 can be driven continuously, and the forward movement of the frames 6 with the moulds stopped at set intervals of time by means of movable stop devices 34. As a further alternative, non-driven rollers can be used in conjunction with so-called timing rods (not shown) which engage at set intervals of time behind the underframe 6 and shift it forwards by one station length, whereafter the timing rods are retracted. In all these cases, as the closed moulds, each together with its mobile frame or underframe, are transported over the endless track extending in the vertical plane, this means that each closed mould with the frame receiving it is continuously moved along the endless track and advantageously the underframes 6 are provided at both ends with projecting buffers 36 and 37 with which the underframes 6 lie contiguously in the forward shifting direction. Such a roller path section 38 is also provided at a cross member 39 which is constructed as a vertically mobile cradle for the mould with the underframe.

There may also be provided as the lifting device a piston-cylinder unit 40, 41 which is hydraulically operated. Displacement of the moulds with the underframe on the upper section of the circulating installation may also be effected by a piston and cylinder unit 42, 43.

In the circulating installation in a vertical plane, about 10 moulds are sufficient. The cycle time for the circulation may be kept relatively short. For example, a periods of 1 5 seconds is sufficient for one time interval, so that the installation has very high performance.

The construction of the conveying device, the moulds and the actuating devices for the displaceable parts of the mould and also for the ejecting device will next be explained, primarily with reference to Figures 4, 5 and 6. As compared with the form of construction of Figure 1, the nature of the mounting of the underframe 6 is illustrated in these Figures as a further variant, namely with running wheels and in this connection the girders 9 of the frame 8 have longitudinally extending rails 45, along which a carriage 46 is moved, in the circulating system, running on these running wheels 47. Mounted on the carriage 46 is the base plate 5 to which the bottom portion 48 of the mould is fixedly connected.The carriage 46 has at its ends the buffers 36, 37. The base plate 5 is provided with centering supports 49 which engage over projecting pin-iike portions 50 which are connected to the carriage 46. In this way, the base plate 5 is readily exchangeable with the mould on the carriage 46. A base plate provided with another type of mould can readily be mounted after removal of the first base plate with exact centering in relation to the carriage 46 and hence to the conveyor track. The possibility of replacement can be utilised not only in the event of damage to a mould but also to enable moulds of different sizes and types to be conveyed at random on the same conveyor. The carriage 46 can take forms other than that illustrated.

The mould comprises mould portions 3 and 4 separated in the longitudinal centre plane, which are opened for the extraction of the case article by displacement in the transverse direction and must be closed against for the casting operation. The displaceable mould parts 3 and 4 are slidably mounted in guides 44 on the common base plate 5. For this purpose, the mould parts lie on slide rails 51 and are guided on a central centering ridge 53, there being provided on the base plate 5 at each end of the transverse sides of the moulds parts 3, 4 a ledge 54 which overlaps a projecting extension 55 of the mould part.In this way, an accurate and reliable displacement of the two parts from and towards one another is ensured without any danger of tilting, with a simple and exchangeable connection between the mould, the base plate and the conveying device which makes it possible to use different types of moulds in the same circulating system, the exchange taking place in a simple and rapid manner, together with the base plate. By utilising, for guiding the displaceable mould parts on the base plate, a slide rail on which the parts bear guided by a central centering bar and an overlapping bar at the end parts of the base plate, it is ensured that the mould parts reach the closing position in accurate mutual alignment, so that manufacture of completely satisfactory castings is ensured.

The actuating members, which are for example, hydraulically driven, for displacing the mould parts 2 and 3 for opening and closing the mould are fixedly mounted on both sides of the conveyor at the stations I and V. For this purpose, the frame 8 has at these stations fixedly located supports 57, 58 on which piston-cylinder units 59, 60 are mounted. The piston rods 61, 62 of these units have at their free ends hooked portions 63, 64, in the recesses 63a, 64a of which there engage extensions 65, 66 which are fixedly connected to the mould parts 3 and 4. In addition, there are provided on the mould parts 3 and 4 stop portions 67, 68, against which the end faces 63a, 64a of the hooked portions 64 and 64 bear for pushing together the mould parts 3 and 4.The recesses 63a, 64a are so provided on the hooked portions 63, 64 that the hooked portions and the extensions 65, 66 mutually afford one another free passage in the direction of movement of the mould, i.e. in the conveying direction. When the mould is run into the stations I and V, the extensions 65,66 of the mould parts automatically enter recesses 63a, 64a of the hooked portions 63, 64. Thereafter, the mould parts 3 and 4 can be opened and closed by means of a pulling dr pushing movement of the lifting cylinders 59, 60. The mould parts remain free from the hydraulic actuating mechanism, so that they can be made with extremely simple design in respect of the performance of the displacing movements.The hooked interengagement of the parts may also be effected by means of a hooked portion on the mould parts. The mould parts are kept closed during the casting operation without any special additional means being required for interlocking or clamping, the mould parts remaining tightly together under gravitational force and friction, even during the casting operation. The stop portions 67, 68 may also serve to bear against correspondingly arranged slide bars in the path of the travel of the mould to the station V and also at the casting station, which slide bars are so arranged and guided that the mould parts are held pressed together between the slide bars.In this way, additional security in the holding-together of the mould parts during casting is achieved, the slide rails acting as closing bars constituting component parts of the track installation, and the moulds themselves do not require for this purpose any additional and costincreasing development, and they remain simple in construction.

A correspoding arrangement in regard to the stationary mounting of the hydraulic actuating members is provided also for the ejecting device 70. This device may comprise a lifting beam 71 which is slidably mounted on rods 72 secured to the base plate 5. Fixedly connected to the lifting beam 71 is a shaft 73 which extends through the bottom portion 48 of the mould and terminates at the upper edge thereof. The shaft 73 is provided with a flange portion 73a which, when the base plate 5 of the mould is mounted on the carriage 46, freely projects through an aperture 74.

Secured to the frame 7 is a hydraulic lifting cylinder 75, of which the piston rod 76 has at its free end a double-hook portion 77, of which the hook ends overlap the projecting flange 73a of the suspended shaft 73. The hook portion 77 can be additionally guided by means of a shoulder 78 on a pin 79. In the extraction station I, the shaft 73 with the flange 73a runs into the aperture 77a of the hook portion 77 on appropriate movement of the underframe 6 with the base plate 5 and the carriage 46. As soon as the mould parts 3 and 4 are pulled apart by means of the fixed cylinders 59, 60 and the casting is thereby freed, the fixed ejection cylinder 75 becomes operative. The base of the hook portion 77 encounters the suspended shaft 73 and drives it and hence push members 73b (Figure 5) upwards, whereby the casting is lifted from the bottom portion 48 of the mould.In the lifted condition, the casting can be taken out of the opened mould by means of an appropriate tongs device. Thereafter, the lifting cylinder 75 is set in operation against and, by means of the hook portion 77 and the shaft 73 engaging with the flange 73a of the shaft 73, it retracts the shaft 73 so that the end faces of the push members 73b are aligned with the surface of the bottom portion 48 of the mould.

For arresting the underframe 6 supporting the mould, with the base plate 5 and the carriage 46 there is employed a device 81 acting as a retaining device. This device comprises a piston and cylinder unit 82 which is hingeably mounted at 83 on a fixedly located pedestal 84 (Figure 4).

The piston 85 has a strap 86 which pivotally engages a double-armed lever 87 at 88, the lever 87 being pivotally mounted on the pin 89. The lever 87 acts on extensions 90 of the base plate 5.

In the respective stopping positions at the stations, the underframe is thus arrested by pressing on the rails 45 or the roller track 33.

For forming the admission and exhaust passages 92 and 93 (Figure 5) in the cylinder head of an internal combustion engine, steel quills are usually employed in light-metal chill casting, these quills requiring a separate hydraulic actuating mechanism in each case. The hydraulic actuating mechanism is then also mounted on the displaceable mould parts, whereby the dead mass of the displaceable mould parts is increased. In addition supply and discharge ducts for the hydraulic system must be provided, which are moved in the circulating system. In order to obviate all these difficulties, in the present apparatus sand cores are used in the moulds for the formation of the exhaust and admission passages in the light-metal chill casting.These sand cores are constructed with the use of core bars 94 and 95 of sand, on which there are provided a number of quill-like extensions 96 and 97 corresponding to the number of passages to be formed. These quill-like sand extensions may each have any desired curvature, so that the passages to be formed extend in accordance with the necessary flow conditions. In order that the core bars 94, 95 carrying the quill-like extensions may be firmly seated in the mould, the core bars 94, 95 extend downwards as far as the bottom part 48 of the mould. This has the result that the outer flange faces at the outlet ends of the passages 92, 93 all brought down to the lower edge 98 of the casting.

Smooth flange faces 99 are then obtained on the longitudinal sides of the casting. This does not cause any difficulty in the provision of elbow connectors, but a substantial simplification of the construction of the mould is achieved. At the same time, the number of components in the devices and tools is considerably reduced. The top core is denoted by 100.

By employing sand cores having arcuate quill extensions for the formation of the admission and exhaust passages in the cylinder head, not only does this lead to a substantial simplification of the construction of the mould parts, but a device for actuating of the steel quills hitherto employed is thus not required, and the additional devices and tools for introducing and withdrawing the steel quills forming the respective passages also become unnecessary, whereby the cost of the whole equipment is additionally reduced. Also, when sand cores are employed with arcuate quill extensions, the possibility of a qualitative improvement of the formation of the admission and exhaust passages of the cylinder head is obtained, and there is no longer any limitation in regard to the arcuate form or the curvature of the passages.As the sand cores for the formation of the admission and exhaust passages are with advantage so formed that the core bars are located between the mould bottom and the displaceable mould parts, the core bars thus simultaneously form the flange faces for the outlet ends of the passages, which are at the same time drawn down as far as the lower edge of the casting. The flange faces thus enlarged secure the position of the core bare with the quill extensions.

It is also possible to use steel quills displaceable along a straight axis for the formation of the admission and exhaust passages in the cylinder head. Such steel quills may be provided outside the mould parts with a ledge with which the fixedly located, hydraulically operated actuating members provided on the track installation can engage, in a similar way to the manner in which the mould parts are displaced.

The bottom portion 48 of the mould is provided with a gate member 102 (Figure 6) in which there is disposed a filling hopper 103 having one or more runners 104 and air extraction passages 105.

The apparatus 107 of Figures 7 and 8 has an endless circulating track in a horizontal plane. The moulds 2 are situated on an endless peripheral conveyor 108, which is preferably constructed as a slat belt 109, which can run either continuously or at predetermined timed intervals. The working stations are denoted by I to VIII. At the station 1, the mould parts are separated from one another, which takes place by means of the actuating members 59 and 60, whereafter the casting can be lifted out and carried away. At the station II, a blowing-out of the open mould parts may take place. At the stations Ill, IV and V, there takes place positioning of the various cores, for example of a bottom core 26 on the bottom portion 48 of the permanent mould, and of sand cores 94 and 95 for forming admission and exhaust passages.

At the station VI, the mould parts are then reclosed by the actuating members 59, 60. At the next station Viol, the top core 100 can be positioned in the closed mould, and after this casting can be effected in the succeeding station VIII by means of the controlled-feed furnace 27. On that section of the circulating track of the conveyor which is free from the working stations I to VIII, there is provided a hood-like covering 110, which is preferably open at the bottom and through which the moulds travel together with the slates on their way to the extraction station. The hook-like covering 110 may commence shortly after the casting station VIII and desirably terminates at a relatively great distance before the extraction station I, in order not to impede the device that extracts the casting, and handling of parts of the equipment. At suitable points, there may be provided extractor fans 111 and 112 adjoined by appropriate discharge ducts.

The covering 110 may further be provided with heating devices 113 and 114 on both sides.

Claims (14)

1. Casting apparatus for manufacturing castings from light-metal alloy by means of moulds in an endless circulating system, wherein each mould has mould parts separable from one another mounted on an endless travelling conveying device; wherein hydraulic actuating members for moving the mould parts for opening and closing the mould and for ejecting a casting from the bottom portion of the mould are disposed at respective working stations and form stationary component parts of an underframe orframe of the conveying device; and wherein there is associated with a section of the conveying device which is free from the working stations a hood-like cover which is closed on at least three sides and which serves as a heating or exhausting device for the closed moulds.

2. Apparatus as claimed in claim 1, wherein an endless track of the conveying device extends in the vertical plane; wherein a lower horizontal portion of this endless track having working stations continuously succeeding one another extends from a separating station by way of further working stations as far as and including a casting station; wherein above these stations an upper portion of the endless track serves for returning the closed moulds; wherein the hooklike cover is associated with this upper return portion of the endless track; and wherein there is provided at the ends of the upper and lower portions of the endless track lifting and lowering devices for lifting and lowering the moulds in closed condition.

3. Apparatus as claimed in claim 1, wherein an idle station is provided between the working stations of the lower portion of the endless track.

4. Apparatus as claimed in claim 2 or 3, wherein each closed mould is transported over the endless track extending in the vertical plane together with a mobile underframe.

5. Apparatus as claimed in any one of claims 2 to 4, wherein the casting station is also the bottom station of the lifting device.

6. Apparatus as claimed in any one of claims 2 to 5, wherein a casting device is disposed at the head end of the lower portion of the endless track.

7. Apparatus as claimed in claim 4 or either of claims 5 or 6 as appendant to claim 4, wherein there are provided on at least one side of the frame at the lifting and lowering stations guide columns on which bent-over support arms are guided for engaging under the mobile underframe.

8. Apparatus as claimed in claim 4, or any one of claims 5 to 7 as appendant to claim 4, wherein the mobile underframe is provided at both ends with projecting buffers.

9. Apparatus as claimed in claim 4, or any one of claims 5 to 8 as appendant to claim 4, wherein a roller track having driven rollers is provided for moving the mobile underframe, these rollers being driven and stopped sectionwise.

10. Apparatus as claimed in claim 4, or any one of claims 5 to 8 as appendant to claim 4, wherein the mobile underframe has running wheels guided on rails of the endless track.

11. Apparatus as claimed in any one of claims 1 to 10, wherein the mould parts of each mould are interengageable with actuating members for opening and closing the mould parts and for raising and lowering a casting ejecting device by means of hooked parts which mutually permit one another free passage in the direction of movement of the moulds.

12. Apparatus as claimed in any one of claims 1 to 11, wherein the mould parts of each mould are so mounted on a common base plate as to be displaceable in guides transversely in relation to the longitudinal axis, and wherein the base plate is mounted by means of centering supports on a mobile plate of the conveying device.

13. Apparatus as claimed in claim 12, wherein the mould parts of each mould lie on slide rails and are guided by a central centering ridge and an overlapping ledge on the base plate.

14. Apparatus as claimed in claim 2, or any one of claims 3 to 13 as appendant directly or indirectly to claim 2, wherein there are provided in the region of the casting station, on both sides of the mould parts of each mould, fixedly located slide bars which interengage with stop members secured to the mould parts and between which the mould parts are held pressed together.

1 5. Apparatus as claimed in any one of claims 1 to 14, wherein for forming admission and exhaust passages in a cylinder head, there are provided sand cores with arcuate quill extensions, and wherein core bars which carry these quill extensions have flange faces extending as far as the lower edge of the casting.

1 6. Apparatus as claimed in any one of claims 1 to 15, wherein the hood-like cover is provided with heating devices and air extraction devices situated at intervals along its length.

1 7. Apparatus as claimed in claim 1, wherein the moulds are disposed on an endless travelling conveying device in a horizontal plane, and wherein the hood-like cover is provided on a section of the conveying device which is free from working stations.

1 8. Apparatus as claimed in claim 17, wherein the conveying device is a slat belt.

1 9. Casting apparatus for manufacturing castings from light-metal alloy, substantially as hereinbefore described with reference to Figures 1 to 6 or Figures 7 and 8 of the accompanying drawings.