US3563302A

US3563302A - Automatic casting having sprue-removing means

Info

Publication number: US3563302A
Application number: US792986*A
Authority: US
Inventors: Marcel Thevenin
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-01-25
Filing date: 1969-01-22
Publication date: 1971-02-16
Anticipated expiration: 1988-02-16
Also published as: FR1559114A

Abstract

An automatic casting machine is equipped with a transfer rod having a tip adapted to be inserted in the sprue of a casting while the sprue is still molten. The mold is then opened, the casting lifted out of the mold by the transfer rod, the tip of which is now fast to the sprue, and transferred to a work table at which the transfer rod, sprue and casting separated from each other.

Description

United States Patent Marcel Thevenin Rue de lAvenir, Champagnole Juea, France Appl. No; 792,986

Filed Jan. 22, 1969 Inventor Patented Feb. 16, 1971 Priority Jan. 25, 1968 France 137,449

AUTOMATIC CASTING HAVING SPRUE- REMOVING MEANS 4 Claims, 4 Drawing Figs.

Int. C1 822d 29/00 Field of Search 164/404, 344, 269, 345, 344,131, 132, 69, 70,334; 249/66,68, 63

[56] References Cited UNITED STATES PATENTS 1,088,233 2/1914 Loesser 249/68 1,387,290 8/1921 Morse r 164/132 1,458,343 6/1923 Kelm 249/63 2,000,449 5/1935 Kistinger 249/63X 2,043,252 6/1936 Kronbach.. 249/63X 2,917,798 12/1959 Ross 22/200 1,128,251 2/1915 Holton 164/69 Pri r 1 t 1[y Eramingr- Charles W. Lanham Assistant Examiner-V. K Rising Attorney-Holcombe, Wetheri11& Brisebois ABSTRACT: An automatic casting machine is equipped with a transfer rod having a tip adapted to be inserted in the sprue of a casting while the sprue is still molten. The mold is then opened, the casting lifted out of the moid by the transfer rod, the tip of which is now fast to the sprue, and transferred to a work table at which the transfer rod, sprue and casting separated from each other.

PATENTEU FEB 1 6 I97! SHEET 1 OF 2 AUTOMATIC CASTING HAVING SPRUE-REMOVING MEANS SUMMARY OF THE INVENTION This invention relates to a foundry for casting metal, especially light alloys. Its object is to provide not only means for automatically carrying out the operations of closing the mold, pouring in the metaL stopping the pouring, and ejecting the castings, but also for carrying out all the subsequent operations of transferring the casting, and removal of the sprue from the casting, which steps are ordinarily carried out by hand by the workmen.

It is an object of the present invention to provide, as a new article of manufacture, a metal-casting machine essentially characterized by the fact that it comprises in combination a crucible provided with heating means for keeping the metal therein molten and a lower outlet from which the metal may be poured, said outlet being controlled by electrical means, a metallic mold equipped with conventional opening, closing, locking and ejecting means, mounted on a carriage, said mold being equipped with electrodes connected in the electric circuit which controls the outlet, a table on which the carriage is driven under appropriate control between a first position in which the tap hole of the mold is located beneath the outlet of the crucible, and a second position in which said tap hole is accessible from the top, and a long transfer rod vertically positi gabove the tap hole in its second position. Thelower end .1; i

transfer rod ends in a cylindrical or slightly conical finger, while its upper end is supported by a hydraulic cylinder capable of moving the transfer rod axially to introduce the finger into the sprue of the casting before that sprue solidifies. This hydraulic cylinder is mounted to be swung about a horizontal axis by a transverse hydraulic cylinder adapted to bring the finger and the sprue of the casting, after retraction and extension of the rod, to a station at which the sprue is separated, and at which a hydraulic cylinder holds the sprue while another hydraulic cylinder assists the longitudinal hydraulic cylinder in the extraction of the finger from the sprue, and at which suitable means separates the sprue from the casting by breaking, cutting or sawing it. The hydraulic cylinder holding the sprue then releases its grip and the sprue falls into a container designed to receive it.

In order that the object of the invention may be better understood,one representative embodiment thereof will now be described, purely by way of illustration and example, with reference to the accompanying drawings, in which:

FIG. I is a schematic elevational view, partially in section, showing the equipment according to the invention;

FIG. 2 is a sectional view, taken along the line II-II of FIG.

FIG. 3 is a sectional view on a larger scale taken through the mold in its closed position; and

FIG. 4 is a view similar to FIG. 3, but showing the mold open.

The installation comprises a crucible 1 inside a furnace 2 and containing the molten metal 3, usually a light alloy. The lower part of the crucible is provided with an outlet 4, normally closed by the pointed lower end of a rod 5, the upper end ofwhich is controlled by an electromagnet 6.

Under the furnace 2 is a casting table 7 on which a carriage 9 travels. This carriage is actuated by a hydraulic cylinder 8 and carries the fixed part 10 of the mold, which is equipped with ejectors II controlled by a hydraulic cylinder 12, and the movable part I3 of the mold, which is controlled by the hydraulic cylinder 14.

In the course of its movements the carriage may take either of two extreme positions defined by the stops I5 and 16 or by contacts at the ends of the path of travel. The first of these positions, shown in broken lines on FIG. 1, is so determined that the top gate 17 of the mold is directly under the crucible outlet 4. In the upper part of the top gate 17 are two electrodes 18 which are insulated from the metallic body of the mold and connected to an electrical circuit which determines the exact moment at which the molten metal reaches the level of the electrodes. A manual or automatic control energizes the electromagnet 6 which causes the molten metal to flow out of the mold, and, when the desired level is attained, closes the circuit between the electrodes 18 which opens the circuit of the electromagnet 6 to discontinue pouring, by means of a cutoff relay connected to said electrodes The hydraulic jack 8 then moves thecarriage into its second position, shown in broken lines on FIG. 1. In this position, and

before the heart of the liquid metal in the top gate which is to become the sprue 19 has had time to solidify, a finger 20 at the end of a vertical transfer rod 21 is introduced into the tap hole. The metal then completes its cooling, thus fastening the sprue to the finger 20.

The transfer rod 21 is moved longitudinally by a longitudinal jack 22 connected to the upper part of this rod and preferably consisting of a compressed air cylinder which is hydraulically cushioned at the end of its stroke to prevent the finger from being too abruptly introduced. This transfer rod 21 preferably comprises a cooling jacket supplied with water through flexible tubes 23.

It is also adapted to move angularly about its upper end, as shown in broken lines on FIG. I. For this purpose the base of the jack 22 is pivotally attached to a stationary member at 24 and to a lateral jack which is adapted to swing the jack 22 about the pivot point 24. In order to avoid bending of the rod '21 in the case of inopportune jamming, the jack 25 preferably acts on the jack 22 through a fork 26 in the direction indicated by the arrow 27, whereas the jack 22 is biassed in the opposite direction by a return spring 28, when the fork is withdrawn. The rod 21 is. guided during these movements by two flat plates 29, and is exactly centered at each of its extreme positions in V-shaped stops 30, as shown in FIG. 2.

After the part 13 of the mold is opened by the jack 14, as shown in FIG. 4, and after the extractors 11 have been actuated by the jack 12, as shown in broken lines on the same figure, the above-described arrangement makes it possible for the transfer rod to be retracted by the jack 22 in the direction indicated by the. arrow 31 in FIG. 4. This longitudinal displacement of the rod 2] draws with it the finger, the sprue I9, and the casting 32 which follows it. The actuation of the jack 25 then moves the assembly to the right of FIG. 1, and, after the rod 21 is again moved in the direction of the arrow 33 by the jack 22, the assembly comprising the casting 32 and sprue 19 comes to rest on a finishing table 34 which is inclined to allow for the swinging motion ofthe rod 21.

Above this table is a jack 35 which actuates a jaw 36 which clamps the sprue 19 against the table 34. A supplemental device then separates the casting 32 from the sprue. This device may comprise a second jack 37 which exerts pressure on the casting and simply breaks the sprue off at the narrow neck by which the sprue is connected to the casting. It is also possible to use a trimming press, or cutting means utilizing a saw, a milling tool, or a grinding wheel. In any case the sprue, and thus the casting, is brought into a precise position in which it is held stationary, and in which it may be recentered in an appropriate mold. It is thus easy to control the abovedescribed devices to carry out the cutting operation with precision.

At the same time that the sprue is removed from the casting, a second device extracts the finger 20 from the sprue. In effect, the force necessary to longitudinally extract this linger is generally greater than the jack 22 is capable of exerting. It is thus necessary, for a short time at the beginning ofthe retracting movement, to exert a greater force on the transfer rod 21. This may be done by utilizing an additional jack 38 which acts on a lever 39 pivotally mounted at 40 on a stationary member and ending in a fork 41 which acts on two projections 42 on opposite sides of the rod 21. After this extraction, the rod 21, still in retracted position, returns to the position shown in solid lines on FIG. 1, ready to pick up the next casting. The jack 35 then releases the sprue 19 which falls into a container 43,

while another container receives the casting, as hereinbefore described.

It will thus be seen that it is possible to produce a large quantity of castings without requiring any manual stop other than the charging of the furnace and the emptying of the

containers

43 and 44. All the operations, which consist in energizing the electromagnet 6 and the various jacks may easily be controlled in an automatic or semiautomatic cycle, although in the former case stop means at the ends of the paths of travel should be provided as a safety precaution.

The finger 20, as has been seen, is a piece of steel which is slightly conical in shape so as to permit the sprue to be firmly attached thereto, while avoiding subsequent difficulty in its extraction. Depending on the castings, the sizes of the sprues and the alloys used, the optimum angle may vary and the finger may even become cylindrical, and possibly comprise several sections of different diameters, but it is clear that one finger may serve for many very different types of castings so that the equipment may quickly be adapted to manufacture any number ofdifferent types of castings by simple adjustment after, of course, changing the mold. For heavy castings it is possible to use several fingers by providing several inlets in the mold for the formation of sprues, in each ofwhich a finger may be seated.

In addition to the advantages of being completely automatic and easy to adapt, the machine according to the invention has the advantage that the introduction of the finger 20 into the sprue just before it hardens improves the quality ofthe casting by accelerating the cooling of the sprue and placing the metal under a little pressure, which avoids the flaws which are often produced in the neck between the sprue and the casting. It is also obvious that the same furnace 2 may receive two crucibles 3 which are symmetrically positioned and which use the same table, equipped with duplicate gripping and cutting devices.

It will of course be appreciated that the above embodiment has been described purely by way of illustration and example and may be modified as to detail without thereby departing from the basic principles of the invention.

In particular, the casting may be air or water cooled to facilitate removal of the sprue. On the other hand, the containers for receiving the castings may be replaced by conveyors which carry the castings to finishing stations.

I claim:

1. In a casting'machine comprising a crucible, a mold having a top gate, and a work station, the improved handling means which comprises a transfer rod having a lower end dimensioned to lie within said top gate while leaving sufficient room therein to permit the formation ofa sprue therearound, means for vertically translating said transfer rod to lift a casting attached to said sprue from said mold, means for swinging said transfer rod from a position above said mold to one in which said casting is supported at said work station, and means for separating said transfer rod, sprue, and casting from each other.

2. A casting machine as claimed in claim 1, in which said handling means comprises fluid pressure actuated means for gripping said separating at said work station so that said transfer rod may be separated therefrom.

3. A casting machine as claimed in claim 1, in which said separating means comprises means for striking said casting while said sprue is held by said gripping means, so as to break said casting away from said sprue.

4. A casting machine as claimed in claim 1, in which said mold is mounted to slide between a first position in which its top gate is beneath the pouring hole of said crucible and a second position beneath the lower end of said transfer rod.

Claims

1. In a casting machine comprising a crucible, a mold having a top gate, and a work station, the improved Handling means which comprises a transfer rod having a lower end dimensioned to lie within said top gate while leaving sufficient room therein to permit the formation of a sprue therearound, means for vertically translating said transfer rod to lift a casting attached to said sprue from said mold, means for swinging said transfer rod from a position above said mold to one in which said casting is supported at said work station, and means for separating said transfer rod, sprue, and casting from each other.