US3512576A - Diecasting machines - Google Patents

Description

May 19, 1970 A. w. PLUME ETAL 3,512,576

DIECASTING MACHINES Filed Nov. 13, 1967 ALAN QALTER PLUME ETAL United States Patent O 3,512,576 DIECASTING MACHINES Alan Walter Plume and Kenneth Francis Faulkner, Ruislip, England, assignors to Heatlock Limited, Ruislip, England, a British company Filed Nov. 13, 1967, Ser. No. 682,180 Int. Cl. B22d 17/12 US. Cl. 164323 Claims ABSTRACT OF THE DISCLOSURE A die-casting machine in which overhead carriages are used to transport upper platens with lower platens clamped thereto between a furnace and a support table, with the platens having therebetween a mold into which molten metal may be introduced when the plates are positioned at the furnace, and the plates are separable when the lower platen rests on its support table to permit setting up of a further mold while another mold associated with another carriage is being used for casting at the furnace.

BACKGROUND OF THE INVENTION This invention relates to die-casting machines of the type in which a die cavity defined by two mold halves is brought to a furnace containing molten metal, with a quantity of molten metal then being transferred into the cavity under the influence of relatively low pressure or vacuum.

It will be appreciated that a considerable amount of time may be spent in transferring the mold from the furnace and in setting up the mold halves and removing the die-cast product therefrom, and it is an object of the present invention to provide an improved die-casting machine in which the above-mentioned disadvantages may be effectively eliminated.

SUMMARY OF THE INVENTION The present invention consists in a die-casting machine which includes a structural framework, a furnace and at least two support tables mounted Within said framework, at least two carriages each mounted upon said framework for movement between a position above the furnace and a position above a corresponding one of said support tables, an upper platen mounted upon each of said carriages and provided with means for raising and lowering said upper platen, a lower platen associated with each of said upper platens, means for securing complementary mold halves to an associated pair of said upper and lower platens, co-operating means on said furnace and said lower platen whereby molten metal may be introduced into the mold through the lower platen and clamping means for linking together an associated pair of said upper and lower platens whereby the lower platen may be transported between the furnace and its support table.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a general diagrammatic view of a die-casting machine according to the present invention, and

FIG. 2 shows a detail of the apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION In carrying the invention into effect according to one convenient mode by way of example, a die-casting machine includes a framework 1 in which are located support tables 2 and 3, defining left-hand and right-hand stations, and a low-pressure furnace 4 at a central station between the tables 2 and 3.

A fresh supply of molten metal is added to the furnace 4, as and when required, from a tiltable container 5 mounted upon a trolley 6 running on a track 7, with a side loading charging aperture with a closure 8 being provided on the furnace for this purpose.

The top of the framework 1 is provided with a track 9 upon which run a first carriage 10 and a second carriage 11. The first carriage 10 is provided with a motor 12 driving a gearbox and magnetic clutch unit 13 for moving the carriage 10 between a position above the left-hand station and one above the center station, and similarly a motor 14 and gearbox and magnetic clutch unit 15 are provided for moving the second carriage 11 between a position above the center station and one above the righthand station. Handwheels 28 are provided for a manual fine adjustment of the position of the carriages 10 and 11.

Each of the carriages 10 and 11 is provided with a hydraulic cylinder 16 operatively connected to an upper platen 17 for raising and lowering such platen, with the platen being guided by four guide bars 18 and having upon its underneath surface T-shaped grooves 17a in which fit clamps 17b for clamping an upper mold half 19.

Each of the two upper platens 17 is associated with a lower platen 20, also provided with T-shaped grooves 20a, upon which rests a lower mold half 21 divided into two portions which may be moved together and apart under the influence of two piston and cylinder units 22 for use in association with a core operated by a piston and cylinder unit 23'.

Each lower platen 20 is provided with four clamps 24 which can be lowered for the purpose of co-operating with brackets 27 mounted on the framework for accurately locating the position of the lower platen and thus of the lower mold half 21 with respect to the up tube (delivery tube) of the furnace 4.

The clamp 24 can also be raised for the purpose of linking the lower platen 20 to the upper platen 17, with the clamps 24 engaging brackets 29 fixed to the upper platen 17.

A typical sequence of operations starting with the position shown in FIG. 1 may be as follows.

The two portions of the lower mold half together with one or more cores are set up on the lower platen 20 resting upon the left hand support table 2. A suitable program is set up in a left hand control unit 25.

The left hand platen is then lowered from the left hand carriage and the two platens are linked together by means of the clamps 24.

When the casting operations on the right hand mold have been finished, the right hand upper and lower platens are linked together by means of the clamps 24 and under the control of a right hand control unit 26 the two platens are raised by the cylinder 16 and then transported by carriage 11 under the influence of motor 14 to a position above right-hand support table 3, with the platens then being lowered onto the table 3- and the clamps 24 being released to permit the platens and thus the mold halves to be parted. A fresh mold may then be assembled upon the upper and lower platens.

Simultaneously under the control of the left hand control unit 25 the upper and lower left hand platens are raised and conveyed by carriage 10 to a central position above the furnace 4.

The platens are then lowered until the lower platen rests upon the furnace, and the clamps 24 then are released and used to position the lower platen accurately relative to the furnace and its up tube.

The upper platen is then closed towards the lower platen with the two mold halves thus being brought together and accurately located with respect to each other by means of tapered dowels. The upper platen exerts pressure to maintain the mold halves together during casting. The furnace is then pressurized under the control of the left 3 hand control unit and molten metal is introduced into the mold.

The pressure is held for a pre-set period and then released, the core withdrawn and the mold halves parted using the upper platen, and the casting extracted, with these operations taking place under the control of the left hand control unit.

This casting cycle is then repeated until such time as the required number of articles have been cast, whereupon the left hand mold is removed to the support table using the carriage 10 While a further mold is presented to the furnace by means of carriage 11.

It will be appreciated that with the above machine, delays in setting up a fresh mold for a different product are eliminated. Moreover, due to the arrangement of the upper and lower platents, when the platents are parted completely, unobstructed access to the die halves is provided without any guide rods or other members extruding between the two plates.

The framework 1 may be hollow and used as an air reservoir, with air being fed thereto under pressure, say 80 psi. and taken therefrom at a lower pressure, for cooling the working area and operators and for providing a supply say at 10 p.s.i. which is further reduced to 3 to 5 psi. for pressurizing the furnace during casting.

The introduction into the furnace of the air under pressure to cause injection of molten metal into the mold cavity and the subsequent venting of the air space to atmospheric pressure after cooling but before the mold is opened may be under the control of two separate rotary valves actuated by piston and cylinder units and provided with limit switches linked to the appropriate control unit 25 or 26 so that a further step in a casting sequence is prevented if a valve is not in its correct position.

Various modifications may be made without departing from the spirit and scope of the present invention.

We claim:

1. A die-casting machine including a structural framework, a furnace and at least two support tables mounted within said framework, at least two carriages each mounted upon said framework for movement between a position above the furnace and a position above a corresponding one of said support tables, an upper platen mounted upon each of said carriages and provided with means for raising and lowering said upper platen, a lower platen associated with each of said upper platens, complemental means for each mold half and each upper and lower platen for securing the mold halves to said upper and lower platens, co-operating means on said furnace and said lower platen for introducing molten metal into the mold through the lower platen and clamping means for linking together an associated pair of said upper and lower platens whereby the lower platen may be transported between the furnace and its support table.

2. Die-casting machine according to claim 1, wherein said means for clamping the platens are arranged to cooperate alternatively with means adjacent the furnace for positioning the lower platen relative to the furnace.

3. Die-casting machine according to claim 1, wherein each of the upper and lower platens is provided with T-shaped grooves and clamping means for sealing mold halves to the platens.

4. Die-casting machine according to claim 1, wherein a control unit is provided for each carriage and its associated platens for controlling an automatic sequence of operations of this carriage.

5. Die-casting machine according to claim 1, wherein at least one platen carries means for operating separate portions of a mold half and at least one core.

References Cited UNITED STATES PATENTS 1,801,922 4/1931 Junghans 164-323 3,049,767 8/1962 Guyot 164-306 3,188,703 6/1965 Le Jeune 164-309 I. SPENCER OVERHOLSER, Primary Examiner R. ANNEAR, Assistant Examiner US. Cl. X.R. 164-306, 339

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