GB2084907A

GB2084907A - Die casting or injection moulding apparatus

Info

Publication number: GB2084907A
Application number: GB8127761A
Authority: GB
Original assignee: HERRMANN PRAZISIONSDRUCKGUSS G
Current assignee: HERRMANN PRAZISIONSDRUCKGUSS G
Priority date: 1980-09-26
Filing date: 1981-09-15
Publication date: 1982-04-21
Also published as: FR2490974B3; GB2084907B; IT8124094A0; IT1139483B; DE3036333A1; FR2490974A1; DE3036333C2

Abstract

In a paraxial arrangement of a die casting machine (1) and a stamping machine (6) for deburring the casting (14), a transfer device is provided between the machines and has a driving shaft (7) which is parallel to their axes and which is fitted with at least one transfer arm (13) displaceable thereon in the direction of the driving shaft, the casting being cast on to the end of the said arm in the casting machine and normally separated therefrom during the stamping operation. To enable the apparatus to pass through a number of working positions, e.g. a cooling tank (9) and a position for measuring or examining the casting, the or each transfer arm 13 can be extended in the direction of its longitudinal axis. For comparatively large castings, the casting machine (1) and the stamping machine (6) are combined to form one unit, in which case one single central column, replacing one column of each of the two machines, accommodates the driving shaft belonging to the transfer device (10)-(13) and consisting of a hollow shaft. <IMAGE>

Description

SPECIFICATION Apparatus for the production of workpieces by die casting or injection moulding The invention relates to an apparatus for the production of workpieces by die casting or infection moulding, consisting of a die casting or injection moulding machine, a stamping machine situated paraxially adjacent thereto and serving to deburr the casting, and a transfer device having a driving shaft which is situated between the machines and parallel to their axes and which has at least one transfer arm displaceable thereon in the direction of the driving shaft, the end of the said arm inserting itself, in one position into which it is rotated, between the mould halves of the casting machine, while in another position into which it is rotated it holds the casting between the stamping tools, the end of the transfer arm being so constructed that the casting is cast onto it on the form-closed principle and is detached from the transfer arm on the occasion of the punching.

Apparatus of this kind is already known (Fr.

Pat.883 248). The great advantage of such equipment resides in the fact that the casting is automatically transferred to the stamping machine without having to be grasped with the hand. The further advantage is that thanks to the mechanical construction and operation of the transfer device the casting is introduced into the stamping machine with complete accuracy, inaccurate insertion being practically impossible. Altogether this results in short station times and reduced wastage. The station time of the transfer device can also be adapted to high machine performances by mounting a number of pins, e.g. four, taking a radial direction, on the driving shaft.

Castings having to undergo a special cooling process after they have been cast are expelled on the casting machine and conveyed into a coolant vessel, from which they have to be transferred to and inserted into the stamping machine either by a conveyor or manually. This process, owing to the mechanical equipment and operations required and the cycle of production involved, proves expensive and is also subject to breakdowns. In such cases the transfer device described in the foregoing cannot be used. This applies in particular to the production of comparatively large castings, which naturally necessitate projecting casting machines and correspondingly larger stamping machines, in addition to which the casting has to be cooled.

The purpose of the invention is to enable an apparatus of the constructional type described above to be designed in such a manner that the casting can be mechanically transferred from the casting machine to the stamping machine and cooled at the same time, even in the case of large castings, without the need for any special conveying devices.

According to this invention, this object is achieved by making the said transfer arm extensible in the direction of its longitudinal axis, e.g. it is mounted so as to be displacable perpendicularly to its driving shaft.

The length of the stroke of the transfer arm depends on the spatial conditions prevailing.

It must be sufficient to ensure that the transfer arm can pass obstacles due to the projecting construction of the machines, e.g. their columns, and enter the retracted position, but can also insert itself between the mould halves of the casting machine or the tools of the stamping machine. This design also enables the casting, after the transfer arm has moved out, to be immersed in a cooling vat, for instance, and then withdrawn therefrom.

There are thus three positions into which the arm can be rotated, i.e. between the mould halves, the cooling vat zone, and between the tools of the stamping machine. If necessary, it may also be given a fourth "position of rotation", in order, for instance, to enable the stamped casting on the extended or retracted transfer to be examined for faulty places or measured.

Known machines of another category are provided, on the transfer arm, with pincershaped grippers for the workpiece, which grip the latter on the casting machine, convey it to the stamping machine and then release it after it has been inserted into the tool. Owing to the movements of the gripper and the necessity to remove it from the space between the tools on each working stroke, this process requires a great deal of apparatus and proves time-consuming. In particular, a method is known in which the transfer arm is caused to perform, between its two positions, a pivoting movement (Ger. Unexamd. Specn.

2523442), a linear movement (Ger. Unexamnd. Specn. 22 35 770) or a combined movement (Ger. Unexamnd. Spec.

23 06 945). It is only in the case of the two types of movement mentioned that three positions can be approached. In this process, however, the transfer device virtually constitutes an independent and expensive conveying device which, in addition, has to be erected in such a way that it is accurately adjusted to the tools. In this known apparatus (Ger. Unaxamd. Specn. 22 35 770) the transfer arm can be prolonged in the longitudinal direction, so that after being stamped, in a retracted position, the workpiece can be moved into a transfer position for further transport. Since this involves two linear movements in succession, the tolerance of the end stops for the two movements may become added together, so that the grippers are no longer guaranteed to be accurately positioned between the tools.In addition, the workpiece cannot be cooled by immersing it in the contents of a cooling vat.

All the aforementioned transfer devices suffer from the drawback of having only one single transfer arm, of which the operation determines the station time of the casting and stamping machine, while the solution provided by the invention enables a number of transfer arms to be mounted on the driving shaft, particularly a number corresponding to the number of positions required, so that the station time of the machine is at all events not determined in advance by an operating speed, which is otherwise slower, of the transfer device.

In one particularly advantageous version of the invention the driving shaft bears a cylinder and piston unit which is transverse thereto and of which the moving part bears the transfer arm. As an alternative, of course, the transfer arm can itself be of telescopic construction.

In a preferred embodiment of the invention the driving shaft bears a support on which are mounted four cylinder and piston units, 90 apart, each having a transfer arm. This construction ensures that there will be one transfer arm present at each of the working positions simulaneously: casting, cooling, stamping and also, if necessary, measuring.

The support is preferably mounted on the driving shaft in such a way as to be displaceable in the direction of this latter, so that the castings on the casting machine and on the stamping machine can be withdrawn at the same time or the transfer arm with the casting moved into position on the stamping machine and the free transfer arm moved into position at the casting point at one and the same time.

The transfer device is advantageously constructed as an accessory which can be mounted between the casting machine and the stamping machine. It can thus be built onto existing units at a later stage.

For relatively large castings multi-column die casting or injection moulding machines can be used, and multi-column stamping machines can be adopted as a matter of course.

Owing to their overhanging construction particular difficulty is naturally encountered in transferring the castings from the casting machine to the stamping machine via a cooling tank mechanically. As a solution to the problems arising in this connection it is proposed according to a further preferred characteristic of the invention that the casting machine and the stamping machine be combined to form one unit and that one column of each of them should be combined to form a single central column situated between them in which case the driving shaft belonging to the transfer device and constructed as a hollow shaft is situated on the said central column.

The invention thus provides, for multi-column machines likewise, a construction in which the guide columns do not excessively impede the operation of the transfer device, so that in general two positions of the transfer arm, with only a moderate length of stroke, prove sufficient. In addition, however, a great advance is achieved, inasmuch as the material involved in the construction of the casting and stamping machine is reduced considerably.

The said casting machine and stamping machine are integrated, as it were, in the form of one unit, so that the forces are absorbed with the minimum of expenditure and effort and the fewer guide devices are involved which require precision operations and constant verification.

In a particularly advantageous version of the invention, for instance, the stamping machine and the casting machine can each be constructed as a three-column machine, the central column being in each case formed by one of the three columns of each of the two machines and being shared by these latter.

Embodiments of apparatus in accordance with the invention will be described by way of example only, with reference to the accompanying drawings of which: Figure 1 is a schematic end view of a fourcolumn casting machine and of a three-column stamping machine with a transfer device mounted between them; Figure 2 is a plan view of the apparatus shown in Fig. 1; Figure 3 is an end view of a casting and a stamping machine combined to form one unit; and Figure 4 is a plan view of the machine of Fig. 3.

The right-hand part of Fig. 1 is a schematic diagram of the mould side of a die casting machine, only the machine housing 2 and the fixing plate 3 as well as four guide columns 4 for the movable half of the mould and one of the mould halves 5 being shown. In the lefthand part may be seen a stamping machine 6, having its axis parallel to that of the die casting machine and positioned beside it. The stamping machine has three guide columns 7 and a housing 8. A cooling tank 9 is mounted in the housing 8.

The guide column 7 belonging to the stamping machine 6 and shown on the right in Fig. 1 also serves as a driving shaft for a support 10 which is mounted thereon for movement parallel to the driving shaft and which bears four cylinder/piston units 11, angularly spaced about the axis of the driving shaft 90 apart from one another. The moving part 1 2 of each cylinder/piston unit bears a transfer arm 1 3 which can be moved in a linear direction from the retracted position into an extended position and which can be rotated by means of and about the axis of the driving shaft 7.

The transfer arm 1 3 in the position shown on the right in Fig. 1 is in the extended position so that its free end is inserted between the mould halves 5, entering as far as the "mould pocket". It is provided at the end with at least one undercut part which is surrounded by the metal poured in, so that after the mould has been opened the casting is connected on the form-closed principle with the transfer arm.

After casting, the support 10 is first of all displaced in the axial direction in order to release the casting from the mould, after which the transfer arm 1 3 is drawn back, the casting thus being extracted from the mould, The support 10 is then rotated through 90 so that that transfer arm 1 3 enters the lower position, the length of stroke being selected to ensure that the casting 1 4 can be moved past the guide column 4 belonging to the die casting machine and situated at the bottom on the left (in Fig. 1) without touching it, finally reaching the lower position. In this position that transfer arm 1 3 is once again moved out until the casting enters the coolant in the position 14'.After being once again retracted that transfer arm 1 3 is moved by means of the driving shaft 7 into the next rotation position between the tools of the stamping machine 6 and inserted in the tool by once again moving the support 10 in the axial direction. With the deburring operation which then takes place the connection between the transfer arm on the one hand and the casting or the surplus burr on the other is nullified, so that the casting can be expelled.

In the example illustrated the transfer arm becomes inoperative when it reaches the upper position.

If a further operation becomes necessary when it occupies this idle position, e.g. if the casting has to be examined for flaws or measured, then the "lug" on the transfer arm will be selected to ensure that the casting, even though it could be deburred by the stamping machine, is still secured by the transfer arm and thus taken out of the machine until it reaches the uppermost rotary position. In this position a suitable tool can be provided for the purpose of finally separating the casting from the transfer arm and expelling it.

In the example shown in Figs. 3 and 4 the casting machine and the stamping machine are combined to form one unit. Thus one common fixing plate 1 5 and one common counter-plate 1 6 are provided, these being interconnected via a total of five columns. Of these latter two columns 1 7 belong to the stamping machine and two columns 1 8 to the casting machine, while one central column 1 9 is common to both units.The movable mould half 21 belonging to the casting machine and driven by a toggle lever 20 is guided on the two columns 1 8 and the central column 19, while the drive 22 of the stamping machine is only guided by the two remaining columns 1 7. Needless to say, this drive can likewise be guided additionally on the central column 1 9.

The support 10 of the transfer device is rotatably mounted on the central column 19, while the transfer device is here again provided with four transfer arms 1 3 (not shown in Fig. 3). The rotary drive 23 for the transfer device 10 can be supported on movable mould half 21.

In the example last described, if the casting does not have to be cooled, or if the cooling is provided simply by movement in the air or by spraying instead of by immersion, the transfer device 10 only requires simple pins 1 3 as transfer arms.

If immersion cooling is required, however, then recourse will be had to extensible transfer arms 1 3 in accordance with the example shown in Figs. 1 and 2.

Claims

1. Apparatus for the production of workpieces by die casting or injection moulding, consisting of a die casting or injection moulding machine, a stamping machine situated paraxially adjacent thereto and serving to deburr the casting, and a transfer device having a driving shaft which is situated between the machines and has an axis parallel to their axes and which has at least one transfer arm rotatable about the axis of the driving shaft, the end of the or each said arm being arranged to insert itself, in one position into which it is rotated, between the mould halves of the casting machine, while in another position into which it is rotated it holds the casting between the stamping tools, the end of the or each transfer arm being so constructed that the casting is cast onto it on the form-closed principle and may be detached from the transfer arm on the occasion of the punching, and in which the or each transfer arm is extensible in the direction of its longitudinal axis.

2. Apparatus in accordance with Claim 1, in which, for each transfer arm, the driving shaft bears a cylinder/piston unit 11 extending transverse thereto and of which the moving part bears the or a transfer arm.

3. Apparatus in accordance with Claim 1 or 2, in which the driving shaft 7 bears a support 10 carrying four cylinder/piston units angularly spaced about its axis 90 apart, each carrying a transfer arm.

4. Apparatus in accordance with any of Claims 1 to 3, in which the or each transfer arm is displaceable on the driving shaft 7 in the direction of the axis of the latter.

5. Apparatus according to any of Claims 1 to 4 including a cooling tank and in which the or each transfer arm is arranged to submerse the workpiece in the tank between the casting machine and the stamping machine by a rotational movement about the driving shaft and a translational movement of the transfer arm parallel to its longitudinal axis.

6. Apparatus in accordance with any of Claims 1 to 5, in which the transfer device forms an accessory and can be mounted be tween the casting machine and the stamping machine.

7. Apparatus, in accordance with any of Claims 1 to 5, with a multi-column die casting or injection moulding machine and a multicolumn stamping machine, in which the casting machine and the stamping machine are combined to form a unit having a common central column and the driving shaft belonging to the transfer device takes the form of a hollow shaft situated on the said common central column.

8. Apparatus in accordance with Claim 7, in which the stamping machine and the casting machine are constructed as three-column machines, the common central column being formed by one of the three columns of each machine.

9. Apparatus for the production of workpieces by die casting or injection moulding substantially as described herein with reference to or as illustrated in the accompanying drawings.