GB1562532A - Counterpessure and low-pressure die casting arrangement - Google Patents

Description

(54) COUNTERPRESSURE AND LOW-PRESSURE DIE CASTING ARRANGEMENT (71) We, NAUCHO-ISSLEDOVATELSKY INSTITUT SPETSIALNYKH SPOSOBOV LITIA, of ulitsa Khimicheskaya 2, Odessa, and NAUcHNo4SSLEDovATELSKY I KONS TRUKTORSKO -TEKHNOLOGICHESKY INSTITUT TEPLOENERGETICHESKOGO PRIBOROSTROENIA "NIrrEKHNoPRiBoR" of ulitsa Oktyabrskoi Revoljutsii 9, Smolensk, both Union of Soviet Socialist Republics, both Corporations organised and existing under the laws of the Union of Soviet Socialist Republics, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described, in and by the following statement: The present invention relates to counterpressure and low-pressure die casting arrangements.

Such arrangements may prove to be most advantageous for producing castings which have to meet exacting requirements as to their physicomechanical properties and fluidtightness, such as high pressure pump bodies or internalcombustion engine cylinder heads.

At present the low-pressure die casting technique has found wide application, this technique consisting essentially in that a casting die under atmospheric pressure is filled with liquid metal fed into the die under a higher gas-pressure; thus, for casting aluminium alloys this pressure amounts to about 0.2-0.8 kgflcm2, the casting being fed additionally during its solidification.

As compared with casting methods based on filling dies under the effect of gravitational pressure of a melt column, the low-pressure die casting technique makes it possible to actually obviate both casting risers and feeders, a feature increasing the utilization of the melt up to 93-98% and providing a 10-20% improvement of the physicomechanical properties of the casting.

Low-pressure die-casting arrangements are made as a sealed furnace with a crucible for the melt and a pipe immersed in said melt, both of them being contained in the furnace body, the upper end of said pipe being fixed in a furnace cover. Said furnace cover mounts a casting die so that its runner, arranged in the bottom portion of the die, is in register with the pipe submerged in the melt. A device for assembly and disassembly of the split casting die and a device for removing the casting from the die are also set up on the furnace cover. On assembly of the die an excess air pressure of about 0.2-0.8 kgf/cm2 is built-up in the furnace; under the effect of said pressure the melt fills the die and upon solidifying of the casting the excess pressure in the furnace is reduced to atmospheric one, whereby the surplus liquid metal flows from the pipe back into the crucible.

Next the die is dismantled, the casting is removed there-from, whereupon the die is re-assembled and the casting cycle is repeated.

During the low-pressure die-casting process the die, both when its cavity is being filled with the melt and during solidification of the casting, is under atmospheric pressure.

However, on some occasions the low-pressure die-casting technique fails to produce the castings featuring the required strength and tightness, insofar as it is impossible to avoid porosity and coarserystaffite structure stemming mainly from the castings solidifying under atmospheric pressure.

The above undesirable phenomena can be eliminated by resorting to the counterpressure casting technique wich essentially consists in that when filling the die with liquid metal and during solidification of the casting both the melt and the die are exposed to the effect to an all-round excess gas pressure which, e.g., for aluminium alloys amounts to about 6-10 kgf/cm2, and the supply of the liquid metal into the die, as well as the feeding of the casting with said liquid metal during its solidifying are effected by providing a difference in the gas pressure within the die and in the pouring vessel. In this case said pressure difference is of the same order as that obtainable during low-pressure die casting.

Counterpressure casting arrangements comprise a pouring device with a partition plate subdividing it into two chambers, the bottom chamber accommodating a vessel for the melt and a pipe interconnecting said vessel and a split casting die disposed in the top sealed chamber, said pipe being mounted movably together with the partition plate with respect to the bottom chamber, said arrangement including a device for assembly and disassembly of the die and a device for removing the castings from said die, the last two devices being located on the body of the top sealed chamber and made movable together with said body but only in a vertical direction. The casting die has one main horizontal parting line and is built-up of two parts, of which the bottom one is fixed stationary on the partition plate, while the top one can move jointly with the body of the top sealed chamber.

When casting under counterpressure on said arrangements the structure of the castings is substantially improved, porosity is practically avoided, the casting solidifying time is cut down, its surface finish is improved and burningon of the sand members of the die to the casting is decreased, insofar as the melt, when filling the die and during the solidification of the casting, is subjected to an excess gas pressure.

Owing to the above-specified peculiarities of moulding the casting material during the counterpressure casting process said process provides a 20-35% enhancement of physicomechanical properties of the castings, as compared with the low pressure die casting technique, along with a several-fold increase in tightness of cast parts. Moreover, said method allows the production of castings from materials which tend to dissociate and decompose on being melted under atmospheric pressure, and the production of castings saturated intentionally with certain gas constituents, this being not feasible in low-pressure die casting.

However, when casting under counterpressure on prior-art arrangements only one die is employed for casting purposes, this diminishing the efficiency of said arrangements.

Moreover, as the devices for assembly, disassembly and removal of the castings from the die are disposed on the body of the sealed chamber, the die can be disassembled only by carrying its top portion vertically, this necessitating the use of dies with one main horizontal parting line, which in turn results in that the prior-art arrangements are applicable only for producing castings of a simple geometry. As is known, intricate castings can be produced only in dies built-up of more than two parts with joints running in various planes.

The application of such dies in the priorart arrangement is impossible, since these arrangements do not comprise devices for splitting the die members in several planes.

The production of large-size castings on the known arrangements also presents a problem, since it necessitates the use of cumbersome gear for disassembly, assembly, and removal of the castings, this gear being disposed on the body of the top sealed chamber. This in turn requires a body of greater dimensions and a considerably more sophisticated locking device ensuring its tightness.

The present invention provides a counterpressure or low-pressure die casting arrangement comprising a pouring device with a partition plate subdividing it into two pressuretight chambers, the bottom chamber accommodating a vessel for the melt, the top chamber being dimensioned to contain a split casting die, the top chamber and the partition plate being movable with respect to the bottom chamber, a pipe for interconnecting the vessel and the die, a die handling machine located outside the top chamber and acting as a device for assembly and disassembly of a split casting die and for removing castings from the die, and means for reiterated introduction and withdrawal of the die to and from the pouring device, arranged on a transporting device which is arranged to carry a die from the die handling machine to the partition plate of the pouring device and back to the machine, the top chamber being tiltable, for access.

This arrangement offers a high production rate, as in service two casting dies can be employed concurrently during one cycle ensuring the forming of a casting in one of the dies while at the same time the other die has its casting removed and is serviced. Moreover, the arrangement allows casting dies adapted for producing castings differing in their geometry, size, and weight to be used one after another.

As the devices for assembly and disassembly of the dies and for the removal of the castings are located outside the body of the top chamber, the design of the pouring device is greatly simplified; it also provides better conditions for low-pressure die casting therein, cuts down metal requirements and overall dimensions of said device and enhances its functional reliability.

Since the devices for assembly and disassembly of the dies and for the removal of the castings are provided by the die handling machine, casting into multiple-part dies composed of more than two parts and having a plurality of combination joints is possible.

Therefore the proposed arrangement can be utilized for producing castings with sophisticated geometry, larger both in size and weight and unobtainable heretofore on prior-art counterpressure casting arrangements, i.e. the casting and technological potentialities of the counterpressure casting arrangements are thus broadened considerably.

A possibility of mounting and removing a casting die from the die handling machine during each casting cycle is provided by supplementing the machine with the device for reiterated introduction into and withdrawal of the dies from the machine, while the presence of the transporting device makes it possible to transfer the casting dies from the pouring device to the die handling machine and back during the casting process, both dies being transferred simultaneously and independently from each other.

The tiltable top chamber of the pouring device provides free access for the transporting device carrying a die to the partition plate; it also improves the servicing of the bottom body of the pouring device and of the pipe, simplifying substantially the filling of the vessel with the melt.

The nature of the invention will be clear from the following detailed description of a particular embodiment thereof, in conjunction with the accompanying drawings, in which: Figure 1 is a general front view of a counterpressure and low-pressure die casting arrangement; Figure 2 is a top view of the arrangement; Figure 3 is a plan view of a die handling machine forming part of the arrangement; Figures 4 and 5 show a die locating device in two extreme positions; Figures 6 and 7 represent a longitudinal cross-sectional view of means for holding the die on a base plate of the die handling machine, the means being shown in two extreme positions; Figures 8 and 9 show means for the ejection of castings from the bottom die part in two extreme positions; Figure 10 depicts movable rods of the die handling machine and means for fastening the die parts; Figure 11, 12 and 13 show a preferred embodiment of the device for reiterated introduction and withdrawal of the dies, and a drive of a transporting device mounting the first device; Figure 14 is a diagrammatic longitudinal sectional view of a preferred embodiment of a pouring device; Figure 15 shows means for locking the die parts on a partition plate of the preferred embodiment of the pouring device.

The die casting arrangement illustrated comprises a pouring device, 1 a die handling machine 2, a transporting device 3 and two dies 4 and 5. The pouring device 1 comprises a body 6 defining a top pressure-tight chamber, a body 7 defining a bottom pressure-tight chamber, a horizontal partition plate 8, a piston-andcylinder device 9 for swinging open the body 6 of the top chamber, and a device 10 for locking the pouring device 1. A preferred embodiment of the pouring device is described below with reference to Figures 14 and 15.

Fastened to the partition plate 8 is a pipe 11 interconnecting a vessel 12 for containing a melt 13, the vessel being arranged in the bottom body 7, and the die 4 (or 5) mounted on the plate 8 under the body 6 of the top chamber.

The arrangement is connected to a compressor plant which supplies gas mlder pressure through a pneumatic system and valves 14, 15 and 16 into each of the chambers of the pouring device 1 and is adapted to bleed the gas from each of the chambers through valves 17 and 18.

Two devices 19 and 19a for the reiterated introduction and withdrawal of the die are disposed on appropriate brackets 20 and 21 of the transporting device 3, said brackets 20 and 21 being fitted with individual drives 22 and 23 and the transporting device being adapted for carrying a die from the pouring device 1 to the die handling machine 2 and back to the device 1. A preferred embodiment of the transporting device is described below with reference to Figures 11 to 13.

The machine 2 (Figure 3) has side plates 24 and 25 with drives 26 and 27 and end face plates 28 and 29 with drives 30,31, for assembling and disassembling of the dies.

Moreover, the machine 2 comprises a base plate 32 which acts as a device for removing the castings from a bottom die part (described below); provision is also made for a device 33 (Figure 1) for taking off the castings removed from the bottom die part.

The plates 24,25, 28,29 have stops 35 disposed in grooves 34 (Figures 4 and 5) of the plates 24,25,28 and 29. The die parts have projections 36 longitudinally entering the grooves 34. End faces of the stops 35 interact with springs 37 whose loading is adjusted by screws 38. The stops 35 act on the projections 36 so as to reduce friction between the die parts and the plates when the die is moved longitudinally of the grooves 34 (i.e.

vertically).

When a die is to be assembled or disassembled or to be stripped of its casting, a bottom die part 39 (Figures 6 and 7), comprising a pusher plate 40 and a guide plate 41, is disposed on the base plate 32 of the machine, being centered on a projection 42. The base plate 32 has openings in which enter fmger-members 43 to eject the castings. Said finger-members 43 are fixed on a movable crossbar 44 travelling along guide rods 45 interconnecting the machine base plate 32 and a plate 46 on which is fixed a hydraulic ram 47 carrying the crossbar 44.

Fixed on the crossbar 44 are brackets 48 with rollers 49 interacting with tracers of die gripping levers 50 articulated on the machine base plate 32. To enable sequential release of the die gripping levers and ejection of the castings by means of the same drive, the hydraulic ram 47 includes a floating piston 51 with a fixed stroke whose detent 52 interacts with a piston 53 connected by a rod 54 to the movable crossbar 44.

A device for ejecting castings 55 from the bottom die part 39 (Figures 8 and 9) comprises hollow pushers 56 arranged in sleeves 57 of the bottom die part and interacting through the plate 40 with the casting. The pushers 56 are fitted with through holes which accommodate balls 58 and which are tapered to prevent the balls 58 dropping out of the holes. Set up on the crossbar 44 on disc springs 59 are the ejectors constituted by the fingermembers 43 passing through the openings in the base plate 32. Each member 43 comprises a base 60 and a bush 61. Contained inside the sleeve 57 of each pusher 56 is a pin 62 with an end face collar 63 and a lead-in chamfer. The pin 62 is urged in the bush 61 by a coil spring 66 acting on a nut 64 whose spherical surface interacts with a tapered washer 65.

The ejector bases 60 are fixed on the crossbar 44 through the disc springs 59 by means of nuts 67.

The machine 2 is equipped with means for fastening all die parts upon their assembly by means of the plates 24, 25, 28, 29. Each die consists of side parts 68 (Figure 10), end face parts 69, a top part 70 and the bottom die part 39. The means for fastening the die parts together include locating pins 71 and 72 with bevelled ends extending from one die part (e.g. 68) into another (e.g. 69), said locating pins 71 and 72 being spring-biased by springs 73 held in their seats by nuts 74.

Grooves 75 of the locating pins 71 and 72 receive the ends of double-arm levers 76 articulated on spindles 77. The other ends of said levers 76 extend beyond the die periphery and interact with axially movable rods 78 of the machine 2.

Figure 11 diagrammatically shows the brackets 20 and 21 of a preferred transporting device 3 arranged on a common column 79 by means of appropriate bearings 80 and 81.

Their drives 22 and 23 each comprise a toothed rack 82 (Figure 13) fixed on the corresponding bracket 20 or 21 and interacting with a pinion 83 fixed rigidly on the column 79. The rack 82 reciprocates under the effect of pistons 84 of hydraulic rams 85. Said motion of the rack 82 is required to turn the brackets in opposite directions.

In the preferred embodiment illustrated in Figures 11 to 13, each of the devices 19 and 19a has vertically movable power cylinders 89 with fixed guiding pistons 87 (Figure 11) whose rods 86 are each secured by way of a tubular member 88 to the corresponding bracket 20 or 21. The cylinders 89 carry a common transverse member or power plate 90 adapted to hold a die 4 or 5. Said plate mounts a means for removing the castings from the top die part, the said means comprising a pusher crossbar 91 urged by a hydraulic ram 92a (Figure 12) on the plate 90 to move along the cylinders 89 functioning as guides of the crossbar 91. The removal of the casting from the top part of the die 4 or 5 (shown only schematically) is effected with the aid of the crossbar 91 acting upon a pusher plate 92 of the top die part.

When introducing the die into and withdrawing it from the machine the liners 89 move in guides 93 fixed on the brackets 20 and 21.

Set up on the power plate 90 is a device for gripping and keeping the die 4 or 5 on the transporting device 3. The gripping device comprises four double-arm levers, of which two levers 94 are articulated on a spindle 95, while two other levers 96 are articulated on a spindle 97, the spindles 95 and 97 being mounted on the power plate 90.

One arm of each lever 94 and 96 interacts with the die 4 or 5, while the other arm is associated with the rod of a respective hydraulic ram 98.

In this case the power plate 90 carries lock rods 99 fixed thereon and rigidly engaging the gripped die when the castings are removed from the top die part. All the hydraulic rams of the brackets 20, 21 are fed from a hydraulic system through the column 79, hydraulic manifolds 100 and corresponding hydraulic control members 101 and 102 with slide valves 103.

In a preferred embodiment of the pouring device (Figures 14 and 15) a device for locking the die in the pouring device (Figure 14) comprises a bellows 104 with a rod 105 provided with a collar 106 and connected to the end of the bellows, an end 107 of the rod 105 carrying a shaped washer 108 that is brought into engagement with levers 109.

Said levers are articulated with the help of brackets 110 and shafts 111 on the body 6 of the op sealed chamber. The opposite ends of the levers 109 interact with the top part 70 of the die and the rod 105 is arranged in a stationary sleeve 112 against which strikes the collar 106. The internal space of the bellows 104 communicates with the cavity of the body 6 through holes 113.

To protect the bellow 104 against mechanical damage in the course of operation, provision is made for a protective hood 114.

The partition plate 8 (Figure 15) is made swingable about a spindle 115; to this end the pouring device is fitted with a hydraulic ram 116 fixed on the body 7 and a leverage 117 associated with the body 6. A flange 118 of the body 7 has an annular projection with an internal water-cooled cavity 123. The partition plate 8 is also provided with an annular projection with a water-cooled cavity 123; it has also a packing ring set up in a groove. A flange 119 of the body 6 is also fitted with a packing ring and a water-cooled cavity 123 as well.

The body 6 is sealed with the aid of hydraulic rams 120, set up on the body 7, and a leverage 121.The partition plate 8 is protected against heat radiation from the body 7 with the help of a shield 122. To enable the partition plate to swing jointly with the body 6, it mounts latches 124 which, rotating about their pivots and entering the corresponding slots in the flanges of the body 6 or 7, connect alternatively and rigidly the partition plate to each of said bodies in turn. The body 7 accommodates an electric furnace 125.

The proposed arrangement, in its preferred embodiment, operates in the following manner.

In the initial disposition the major working members of the arrangement occupy the positions represented in Figures 1 and 2, the bracket 20 of the transporting device 3 being arranged above the machine 2. The power plate 90 of the device 19a for reiterated introduction and withdrawal of the die 4 is in its top position, while its levers 94 and 96 keep the die, with the solidified casting, above the machine 2. The parts of the machine 2 occupy the positions shown in Figure 3, the plates 24, 25,28,29 are brought together, the levers 50 for holding the die on the base plate 32 are separated, as shown in Figure 7, and the device 33 for taking off the castings is set to a position, given in Figure 1, the means for ejecting the castings from the bottom die part 39 being set to the position shown in Figure 8.

The bracket 21 is in its intermediate position between the machine 2 and the pouring devices, the power plate 90 of said bracket being set to its top position and the levers 94 and 96 being brought apart. The die 5 has been set up on the partition plate 8 so that its runner communicates through the pipe 11 with the vessel 12 filled with the melt 13, and the body 6 of the top chamber of the pouring device 1 is open. Next, under the effect of the leverage 117 (Figure 15), the hydraulic ram 116 swings the body 6 through 90 to closure, whereupon said body 6 is locked by the hydraulic rams 120 and the other leverage 121. By virtue of the packing rings of the flange 119 and the projection on the partition plate 8 the body 6 is sealed, and by virtue of the packing ring of the plate 8 and the projection on the flange 118 of said body 7, the latter is sealed as well.

The compressor plant or the shop network supplies compressed gas through the pneumatic system comprising the valves 14, 15 and 16, and as a result the same pressure is built-up in the bottom and top chambers, said pressure varying, e.g. when casting aluminium alloys, from 6 to 10 kgf/cm2. By bleeding the gas from- the top chamber through the valve 17 or by building-up the pressure in the bottom chamber, a pressure difference is created that is equal, e.g. when casting aluminium alloys, to about 0.2-1.0 kgf/cm2, said pressure difference being developed according to a given program, according to which the die 5 is filled with liquid alloy at a preset variable speed.

When building-up a gas pressure the body 6 the compressed gas passes through the holes 113 (Figure 14) into the internal space of the bellows 104, which under the effect of said gas pressure expands and moves the rod 105 upwards. In this case the end 107 of said rod 105 carries the shaped washer 108 upwards, the washer 108 turning the levers 109 about the shafts 111 of the brackets 110. The bottom ends of the levers 109 acting on the top part 70 of the die 5 urge said die part to the bottom part 39 locking thus said parts, as shown in Figure 14. If the die is composed of more than two parts (side, end, etc) the body 6 should mount several locking devices, similar in design and operating in a similar manner to the aboveoutlined locking device.

After a holding period that is required for the casting to solidify, the cas pressures in the cavities of the bottom and top chambers become equal, whereupon they are simultaneously decreased by opening the valves 17 and 18. At a drop in pressure of the compressed gas in the body 6 said gas escapes from the interior of the bellows 104, relieving thereby the extension forces of said bellows 104, and under the effect of resilient forces of the bellows material the rod 105 drops down and the washer 108 turns the levers 109 about the shafts 111 of the brackets 110 to their initial position, releasing therefore the top die part 70 and, hence, unlocking the casting die 5.

To preclude excessive extension of the bellows 104 during idle trials of the pouring device without a die the rod 105 is fitted with a collar 106 which strikes against the sleeve 112 limiting the stroke of the rod 105 and, hence, protecting the bellows 104 against excessive extension which may cause its damage. Upon cancelling the gas pressure the body 6 is unlocked and opens with the help of the leverages 117 and 121 lifting it through 90 . In thie case the partition plate 8 is held on the flange 118 of the body 7 of the bottom chamber by means of the latches 124. The die 5 with the solidified casting is removed from the partition plate and carried to the machine 2.

If at any time it is necessary to examine the vessel 12 or to add the melt therein, or to inspect and repair the pipe 11, the casting die is removed from the partition plate and the body 6 is closed, whereupon the partition plate 8 is fastened to the flange 119 of the body 6 by the latches 124. Next by using the leverage 117 the hydraulic ram 116 lifts the body 6 together with the partition plate 8 fixed thereon through 90 . In this case the pipe 11 swinging together with the partition plate 8 comes out of the vessel 12 to a horizontal position which is convenient for both examination and repair of said pipe. The melt is added, if required, into the vessel 12 of the open bottom chamber and the latter is examined and cleaned. Following that, the body 6, together with the plate 8 and pipe 11, is swinging down by the hydraulic ram 116 and the leverage 117, the plate 8 being set up on the flange 118 of the body 7, whereupon the body 7 is fastened by means of the latches 124 to the partition plate 8 and the body 6 is open again. The pouring device 1 returns to its initial disposition.

On completion of the above operations of the pouring device, after the casting 55 has solidified in the die 5, the drive 23 swings the bracket 21 round through 900, the bracket being thus arranged above the pouring device.

Next the cylinders 89 lower the power plate 90 and the lock rods 99 come in contact with the top part 70 of the die 5. Following that, the levers 94 and 96 grip the die 5 by means of the hydraulic rams 98. Next the cylinders 89 raise the plate 90 and lift the die 5 with the casting 55 from the plate 8 of the pouring device. On completion of the die lifting operation the drive 23 turns the bracket 21 to its intermediate position.

While the body 6 was being closed for pouring the die 5, the bracket 20 of the device 19a for the reiterated introduction and withdrawal of the die 4 under the effect of the cylinders 89 lowered the power plate 90 with the die 4. As a result, the projections 36 of its side parts 68 and end face parts 69 are free to enter the grooves 34 of the side plates 24 and 25 and the end face plates 28 and 29 longitudinally, coming in contact with the rounded off ends of the spring-biased stops 35 (which urge the parts 68, 69 away from the plates in order to reduce friction), the guide plate 41 of the bottom part of the die 4 being centered on the projection 42 of the machine base plate 32 so that the holes in the die pushers 56 are axially aligned with the pins 62. In this case the movable base plate crossbar 44 of the diecasting machine is in its bottom position (Figure 7), the pins 62 with the collars 63 being lowered below the top plane of the base plate 32, as shown in Figure 8.

Upon mounting the die 4 on the machine base plate 32 in compliance with the operating program of the proposed arrangement a command is sent to lift the piston 51. Under the effect of the working fluid fed beneath the piston 51 (th rod and interpiston spaces being in this case in communication with a drain), the latter moves by a definite value and acting on the piston 53 with the help of the detent 52 raises the crossbar 44 which in turn acts with the help of the rollers 49 fixed in the brackets 48 on the levers 50 and swings them sufficiently to grip the bottom part 39 of the die 4, which is then disassembled.

The disassembly of the die 4 is initiated by moving the end face plates 28 and 29 of the machine. In this case during the forward stroke at the beginning of the stripping operation the rods 78 (Fig. 10) on the end face plates 28 and 29 act on the ends of the levers shown in Figure 8. To provide synchronous motion of all the finger-members 43 fixed on the crossbar 44 and a possibility of adjusting the initial position of the end faces of said bushes 61, the bases 60 of the finger-members 43 are secured in the crossbar 44 on the disc springs 59 compressed by the adjusting nuts 67.

The piston 53 moves to the initial bottom position under the pressure of the working fluid being built-up in the rod space of the hydraulic ram 47 with the other spaces of said ram being connected to a drain. In this case the crossbar 44, on being carried to its bottom position, acts with the rollers 49 set up in the brackets 48 on the tracers of the levers 50 and at the end of the stroke the rollers 49 swing said levers releasing the bottom die part 39 and carrying the base plate 32 of the machine 2 to its initial position, as shown in Figure 7.

After the removal of the casting from the bottom die part, and after cleaning, blowing and whitening of the working die surfaces, the die is re-assembled.

The side parts 68 of the die are assembled on its bottom part 39 held on the projection 42.

The side die plates 24 and 25 are carried with the side parts 68 of the die by the drives 26 and 27 (Figure 3). To preclude the transmission of tilting forces to the bottom die part 39 the side plates 24 and 25 are fitted with devices limiting their plate motion during assembly, while the side parts of the die are provided with guide pins. Next the top die part 70 is lowered with the help of the device for introduction and withdrawal of the die, the end face plates 28 and 29 of the machine 2 closing, with the end face die parts 69 mounted thereon.

In this case the end face die parts acting on the chamfers of the locating pins 71 and 72 move them, compressing the springs 73. At the end of said motion of the end face die parts 69 the pins 71, 72 enter under the effect of the springs 73 the registering seats in the end face die parts 69 and fasten the side and end face die parts together. During that operation the rods 78 are withdrawn and do not act on the levers 76. The lower and top die parts are fastened to its side parts in a similar manner.

As a result of the above operations, the die parts are assembled and fixed into a single die.

On completion of the assembly and fastening of the die parts the stops 35 under the effect of the springs 37 overcome the friction force and urge the die plates 24,25, 28 and 29 to move away from the corresponding die parts, providing all-round clearance between the grooves 34 of the die plates and projections 36 of the die parts (Figure 5). The assembled die 4 released from the said plates and from the base plate of the machine 2 is lifted with the aid of the device 19a and is swung on the bracket 20 in a horizontal plane by the transporting device 3 through 1800, being thus arranged on the other side of the bracket 21. As a result, the die 4 is disposed above the pouring device 1. Next the die is lowered on to the partition plate 8 of the pouring device so that the runner opening is in register with that of the pipe 11. The levers 94, 96 are brought out of engagement with the die and the power plate 90 rises. Simultaneously with the swinging of the bracket 20 with the assembled die 4 the bracket 21 with the die 5 accommodating the solidified casting swings from its intermediate position through 90 and stops above the machine 2.

The first half of the arrangement operating cycle is completed. The second half-cycle is effected in a similar manner, the only difference residing in that the device 19a for the introduction and withdrawal of the die operates with the die 4 mounted on the pouring device 1 while the similar device 19 operates with the die 5 set up on the machine 2. On completion of the entire cycle the arrangement returns to the initial disposition.

The above-described operating cycle of the proposed arrangement is reiterated.

If during the cycle of disassembling the die on the machine 2 the casting remains in the top die part 70, the latter together with the casting is lifted upon stripping the end face and side die parts, said operation being effected by the devices 19 and l9a. Upon setting the bracket of the transporting device 3 to its intermediate position the casting is removed from the top die part to a receiving pan. To this end the pusher crossbar 91 is lowered by means of the hydraulic ram 92a fixed on the power plate 90, said crossbar 91 acting upon the pusher plate 92 of the top die part 70 and pushing-out the casting. During the transfer of the pusher crossbar 91 the cylinders 89 function as guides and the levers 94 and 96 acting through the top die part 70 on the lock rods 99 hold the top die part 70 and limit the casting removing force to the power plate 90, relieving the brackets of the transporting device and the column 79 from said forces. Upon removing the casting from the top die part 70 the power plate 90 is raised, the swinging means turning again the bracket of the transporting device and setting it to a position above the die-casting machine. Next the power plate 90 descends and the machine 2 assembles the die parts. As to the operation of the other devices of the proposed arrangement in the course of the cycle, it is effected similarly to the above outlined.

The herein-proposed arrangement enables the production of both simple and intricate sound castings by using casting dies with various parting lines, such as: - dies with a single horizontal parting line; - those with a single vertical parting line; - those with two parting lines: a horizontal and a top vertical one; - dies with two parting lines: a horizontal and a bottom vertical one; - dies with three parting lines: a vertical one, a top and a bottom horizontal one.

Use can be made of dies provided with additional parting lines.

The arrangement is adaptable for producing castings in dies whose bottom half is fixed on the partition plate 8. In this case the casting is removed from the top half of the die either upon raising the power plate 90 with the top half of the die from the pouring position or upon turning the bracket to its intermediate position.

The transporting devices may be arranged to operate simultaneously with more than two dies.

When the proposed arrangement is used for low-pressure die casting, its operation differs only in that, for pouring the die, an excess gas pressure is created through the open valves 14 and 15, in the cavity of the bottom chamber of the pouring device, the body 6 being at this time open and the die being under atmospheric pressure.

WHAT WE CLAIM IS: 1.A counterpressure or low-pressure die casting arrangement comprising a pouring device with a partition plate subdividing it into two pressure-tight chambers, the bottom chamber accommodating a vessel for the melt, the top chamber being dimensioned to contain a split casting die, the top chamber and the partition plate being movable with respect to the bottom chamber, a pipe for inter < onnect- ing the vessel and the die, a die handling machine located outside the top chamber and acting as a device for assembly and disassembly of a split casting die and for removing castings from the die, and means for reiterated introduction and withdrawal of the die to and from the pouring device, arranged on a transporting device which is arranged to carry a die from the die handling machine to the partition plate of the pouring device and back to the machine, the top chamber being tiltable for access.

2. An arrangement as claimed in claim 1, in which the die handling machine is provided with spring-biased stops arranged in grooves of die-engaging plates of the machine, the stops being adapted to bear against flanges on given die parts in order to urge the die parts away from the plates, and with means for holding the die on a base plate of the die casting machine, the base plate having a movable crossbar, the said holding means comprising driven articulated levers with tracer grooves accommodating rollers mounted in brackets of the said crossbar, the levers being adapted to grip a bottom die part.

3.An arrangement as claimed in claim 2, in which the base plate of the die handling machine is provided with means for removing castings from the bottom die part, the said means comprising bushes arranged on the movable crossbar, the bush- bases accommodating collar-ended pins mounted on resilient members, the bushes and pins being so arranged that when removing the castings the bushes can interact with bottom die part pushers, the pushers being hollow and the pins being free to enter the pushers, and as the pushers of the bottom die part return to their position the collars on the pin end faces are able to interact with balls mounted in the pushers and running therein.

4. An arrangement as claimed in claim 3, in which the means for holding the die on the base plate of the die-casting machine and the means for removing the casting from the bottom die part have a common drive comprising a power cylinder which is set up on the base plate and which comprises a piston secured to the crossbar and a floating piston which interacts with the first piston in the course of the die being gripped on the base plate.

5. An arrangement as claimed in any of claims 2 to 4, in which the die plates of the die casting machine are provided with rods movable axially, capable of interacting with the die parts and fitted with means for fastening the said parts into a single die, the fastening means comprising grooved pins, spring-biased and movable axially, and double-arm articulated levers with one arm of each lever being accommodated in the groove of the corresponding pin and being able to interact with the said pin, while the other arm can interact with the rods.

6. An arrangement as claimed in any of claims 1 to 5, in which the transporting device comprises a bracket mounted turnably on a column, the bracket having a rotary drive arranged on the top of the bracket, the means for reiterated introduction and withdrawal of the die of the die casting machine being mounted on the bracket.

7. An arrangement as claimed in claim 6, in which the rotary drive of the bracket comprises a toothed rack fixed on the bracket and interacting with a gear disposed on the column, the racks being arranged to reciprocate to turn the bracket in opposite directions.

8. An arrangement as claimed in claims 1 to 7, in which the means for reiterated introduction and withdrawal of the die comprise vertically acting jacks which carry a common transverse member and which carry means for ejecting the casting from the top die part, the transverse member being fitted with means for gripping and keeping the die on the transporting device.

9. An arrangement as claimed in claim 8, in which the means for gripping and keeping the die on the transporting device comprises driven double-arm levers, with one arm of each lever being able to interact with the die, the transverse member carrying lock rods fixed thereon and rigidly engaging the gripped die as the casting is being removed from the top die part.

10. An arrangement as claimed in any of claims 1 to 9, in which the top chamber of the pouring device is provided with means for locking the die parts on the partition plate,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   and a bottom vertical one; - dies with three parting lines: a vertical one, a top and a bottom horizontal one.

   Use can be made of dies provided with additional parting lines.

   The arrangement is adaptable for producing castings in dies whose bottom half is fixed on the partition plate 8. In this case the casting is removed from the top half of the die either upon raising the power plate 90 with the top half of the die from the pouring position or upon turning the bracket to its intermediate position.

   The transporting devices may be arranged to operate simultaneously with more than two dies.

   When the proposed arrangement is used for low-pressure die casting, its operation differs only in that, for pouring the die, an excess gas pressure is created through the open valves 14 and 15, in the cavity of the bottom chamber of the pouring device, the body 6 being at this time open and the die being under atmospheric pressure.

   WHAT WE CLAIM IS: 1.A counterpressure or low-pressure die casting arrangement comprising a pouring device with a partition plate subdividing it into two pressure-tight chambers, the bottom chamber accommodating a vessel for the melt, the top chamber being dimensioned to contain a split casting die, the top chamber and the partition plate being movable with respect to the bottom chamber, a pipe for inter < onnect- ing the vessel and the die, a die handling machine located outside the top chamber and acting as a device for assembly and disassembly of a split casting die and for removing castings from the die, and means for reiterated introduction and withdrawal of the die to and from the pouring device, arranged on a transporting device which is arranged to carry a die from the die handling machine to the partition plate of the pouring device and back to the machine, the top chamber being tiltable for access.
2. 2. An arrangement as claimed in claim 1, in which the die handling machine is provided with spring-biased stops arranged in grooves of die-engaging plates of the machine, the stops being adapted to bear against flanges on given die parts in order to urge the die parts away from the plates, and with means for holding the die on a base plate of the die casting machine, the base plate having a movable crossbar, the said holding means comprising driven articulated levers with tracer grooves accommodating rollers mounted in brackets of the said crossbar, the levers being adapted to grip a bottom die part.
3. 3.An arrangement as claimed in claim 2, in which the base plate of the die handling machine is provided with means for removing castings from the bottom die part, the said means comprising bushes arranged on the movable crossbar, the bush- bases accommodating collar-ended pins mounted on resilient members, the bushes and pins being so arranged that when removing the castings the bushes can interact with bottom die part pushers, the pushers being hollow and the pins being free to enter the pushers, and as the pushers of the bottom die part return to their position the collars on the pin end faces are able to interact with balls mounted in the pushers and running therein.
4. 4. An arrangement as claimed in claim 3, in which the means for holding the die on the base plate of the die-casting machine and the means for removing the casting from the bottom die part have a common drive comprising a power cylinder which is set up on the base plate and which comprises a piston secured to the crossbar and a floating piston which interacts with the first piston in the course of the die being gripped on the base plate.
5. 5. An arrangement as claimed in any of claims 2 to 4, in which the die plates of the die casting machine are provided with rods movable axially, capable of interacting with the die parts and fitted with means for fastening the said parts into a single die, the fastening means comprising grooved pins, spring-biased and movable axially, and double-arm articulated levers with one arm of each lever being accommodated in the groove of the corresponding pin and being able to interact with the said pin, while the other arm can interact with the rods.
6. 6. An arrangement as claimed in any of claims 1 to 5, in which the transporting device comprises a bracket mounted turnably on a column, the bracket having a rotary drive arranged on the top of the bracket, the means for reiterated introduction and withdrawal of the die of the die casting machine being mounted on the bracket.
7. 7. An arrangement as claimed in claim 6, in which the rotary drive of the bracket comprises a toothed rack fixed on the bracket and interacting with a gear disposed on the column, the racks being arranged to reciprocate to turn the bracket in opposite directions.
8. 8. An arrangement as claimed in claims 1 to 7, in which the means for reiterated introduction and withdrawal of the die comprise vertically acting jacks which carry a common transverse member and which carry means for ejecting the casting from the top die part, the transverse member being fitted with means for gripping and keeping the die on the transporting device.
9. 9. An arrangement as claimed in claim 8, in which the means for gripping and keeping the die on the transporting device comprises driven double-arm levers, with one arm of each lever being able to interact with the die, the transverse member carrying lock rods fixed thereon and rigidly engaging the gripped die as the casting is being removed from the top die part.
10. 10. An arrangement as claimed in any of claims 1 to 9, in which the top chamber of the pouring device is provided with means for locking the die parts on the partition plate,

    the locking means comprising double-arm driven levers, one of the arms of each lever interacting with the die, the lever being driven by a bellows via a rod, the bellows space communicating with the top chamber and the bellows rod being provided with a limiting collar and interacting with the other arm of each of the said levers.
11. l l. An arrangement as claimed in any of claims 1 to 10, in which the partition plate is tiltable relative to the top chamber about the same axis, the plate being provided with means for connecting it alternatively to the top or bottom chamber.
12. 12. A counterpressure casting arrangement substantially as described herein with reference to, and as shown in, the accompanying drawings.