US2983003A - Automatic die casting machine - Google Patents

Description

May 9, 1961 Filed Oct. 27, 1958 4 Sheets-Sheet 1 IN l/[NTOR M. THEVENl/V May 9, 1961 Filed Oct. 27, 1958 M. THEVENIN AUTOMATIC DIE CASTING MACHINE 4 Sheets-Sheet 3 W Wm m May 9, 1961 M. THEVENIN AUTOMATIC DIE CASTING MACHINE 4 Sheets-Sheet 4 WWII/77R Filed 001;. 27, 1958 M, THEVENIN wy 2;: M

United States Patent This invention relates to an improved automatic die casting machine characterized by the fact that it comprises in combination with a pivotally mounted principal carriage carrying the mold and with a meltingpfurnace providedwith a tap hole, means for bringing the mold, while closed, into position under the tap hole, means for automatically opening the tap hole when the closed mold is placed thereunder, means for automatically closing the tap hole when the mold has been filled with molten metal, means for automatically pivoting the mold carry-' ing carriage to a mold opening position, means for automatically opening the mold when it is placed in that position, means for automatically removing the core or cores from the mold, mechanism carrying'ejectin'g means passing through one of the sections of the mold to automatically eject the casting from the mold, means for reclosing the mold, means for automatically repositioning'one or more cores within the mold, means for returning the ejection mechanism to its initial position with respect to 'the mold, in which position the ejecting means completes the closing of the mold, and safety means for blocking the tap hole whenever the mold is not completely closed and in a position to receivemetal poured thereinto. I

K In a preferred embodiment of the invention a rotating electric switch is used to control the pivoting of the shaft at regular intervals toward the mold filling and mold emptying positions, and also to control the opening and closing of the mold, which comprises a mold section mounted on an auxiliary carriage sliding on the prinicipal carriage. The movement of the auxiliary carriage carrying the movable mold section as it opens and closes causes the cores to be, inserted in or withdrawn from the 'mold, and the movement of the cores 'actuates the ejecting means which pass through the movable mold sections. All ;of these movements are preferably powered by pneumatic cylinders controlled by two way electromagnetic valves of a known type.

The characteristic features of the invention and the particulars of a casting machine which embodies it will more fully appear in the course of the following description of one embodiment thereof which is set forth purely by way of example, without limiting the scope of theinvention to the specific details of that embodiment. This embodiment is illustrated in the accompanying schematic drawings, on which:

Fig 1 is a planyiew of an assembly comprising the pivoting principal carriagewhich carries the mold, and theja'lixiliary carriagessliding on the principal carriage and carrying the core and the casting ejecting means respectively. l

Fig'. 2' is" a plan view on a reduced scale showing the same carriage assembly after the casting has been removed and the mold reclosed.

Fig, 3 is also a plan view showing a core in place when tnemold i reclosed;

Fig. is a similar plan View showing the withdrawal of the injectors with the mold in casting position.

Patented May 9, 1961' Fig. shows the carriage in position under the furnace for pouring of the molten meta Fig. 6 is a schematic view showing the automatic arrangement for controlling the opening of the tap hole.

Figs.' 7 to are schematic plan views respectively showing the carriage returned to the casting removing position, the opening of the mold, the withdrawal of an axial core, and the control of the carriage carrying the ejecting means which force the casting from the mold.

Fig. 11 is a schematic diagram of the electrical circuit in conjunction with the compressed air system which controls the opening and closing of the mold as well as the movement of the principal carriage toward the filling position or toward the casting removal position.

The automatic die casting machine herein described comprises a principal frame or carrier which is generally rectangular in shape and mounted to pivot around a vertical shaft 2between two extreme positions, at one of which th'e'molten' metal is delivered into vthe mold' and at the other ofwhich the casting is ejected from the mold. t I

.The mold is composed of two parts, one of which (3) is stationary and'fixed to a cross member 4 on the carriage 1, andthe other. of which (5) is movable-and fixed to a transverse member 6 mounted on a first auxiliary carriage comprising side rails 7 connected at one end by another transverse member 8 attached to the piston 9 of a pneumatic cylinder 10. The side rails 7 are slidably supported on the carriage 1 so that the auxiliary carriage can be reciprocated by the piston 9 parallel to the side rails of the principal carriage between two extreme positions, at one of which the mold is closed and at the other of which the mold is opened to eject the casting therefrom. v a

A second auxiliary carriage 11 is mounted toslide on the rails 7 and is reciprocated by the rod 12 of a piston which slides in a cylinder 13. The end of the rod 12 and'the end of the cylinder 13 are each articulated to a pair of levers 14 and 15 (Fig. 3), which are pivotally connected to each other, to the cross bar 8 of the first auxiliary carriage, and to a cross bar 16 forming part of the carriage 11. The carriage 11 carries an axial.

core '17 adapted to be positioned in the mold'before it is filled with metal.

A third auxiliary carriage 18 is slidably mounted on fixed on the carriage 11, when this projection bears in one direction or the other against the arm 23 of a switch 24 mounted on the carriage 18.

Air is supplied to the cylinder 13 when cams 25 and 26 act on a system of articulated levers which control two three- way valves 27 and 28, either directly, or by opening or closing the supply circuits for these electrO- I magnetically controlled valves. p

As seen on Fig. 2, the carriage 1, which is pivotally mounted on the shaft 2, is shown in the position in which the casting has already been ejected and 'im-j' mediately after the mold has been reclosed by sliding the carriage 678 in the direction indicated by the' arrow f with respect to the carriage 1. The pivotal movement of this carriage 1 is controlled by an air cylinder 29, the cylinder of which .is pivotally attached to a fixed shaft 30, while piston rod of this cylinder is arti culated to a shaft 31 fixed to a diagonal bar 32 mounted, on the carriage 1. The cylinder 10, which reciprocates the carriage 678, is periodically actuated by C,

The cam 25 carried by the cross bar 8 of the carriage 6 actuates the valve 27, thus withdrawing the rod of the piston 12 intothe cylinder 13, thereby straightening the lever pairs 14 and 15, displacing the carriage 11 in the direction of the arrow g (Fig. 3), and positioning the core 17 in the mold.

' As the carriage 11 moves to position the core 17 in the mold, the projection 22 comes to bear against the switch 24 which controls the valve which supplies compressed air to the cylinder 20 so that the carriage 18 which carries the ejectors withdraws in the direction of the arrow h shown in Fig. 4, so that the ejectors no longer project into the interior of the movable mold section, but only close it off. j

Starting from this position in which the mold is closed and ready to receive a charge of molten metal, the same rotary switch which periodically brings about the closing (and the opening) of the mold also periodically actuates the electromagnetically controlled valve (not shown) which controls the supply of compressed air to the cyllinder 29 so that the carriage 1 (see Fig. after havbell passes through the electromagnet 37, but is too weak to energize it and lift the plug 34.

After the metal has flowed into the mold, the'rotating switch which has already been mentioned actuates the air cylinder 29 which pivots the carriage 1, as shown in Fig. 7, in the direction of the arrow L. Then this switch acts to open the mold through displacement of the carriage 6-7-8 as shown in Fig. 8, in the' direction of the arrow F. The cam 26 carried by the cross member 8 comes to bear against the valve 28, thus driving the rod of piston 12 out of the cylinder 13, and withdrawing the core 17 from the mold section 5 as a.result of the movement of the carriage 11 in the direction of the arrow G in Fig. 9. The movement of the carriage 11 brings the projection 22 to bear on the switch 24 and thus causes the carriage 18 which carries the ejectors to advance, in the direction of the arrow H in Fig 10.

ing pivoted about its shaft 2 in the direction of the arrow 1, comes into position under a melting furnace 33, the plug 34 of which is made of steatite or corundum and is perpendicularly positioned above the hole provided in the mold to receive the molten metal.

It is, of course, desirable that it be impossible for the metal to be poured into the mold unless the mold is ready to receive it. Figure 6 shows one embodiment of a satisfactory safety device, but it will be understood that it is disclosed purely by way of example, and that other embodiments are possible. Reference numerals 35 and 36 indicate electric lines supplied from anyconventional source of electric current. The plug 34 is provided with a steatite tip which closes the tap hole by engaging a steatite seat. This plug is lifted when the current energizes an electromagnet 37. However, the supply circuit for the electromagnet 37 passes through a movable contact 38 fixed to the carriage 11, through a movable contact 39 mounted on the carriage which carries the movable mold section 5, through a switch 40 which can be closed only by means of an abutment 41 on the carriage 1 when the latter is in pouring position, through a normally closed electromagnetically actuated switch 42. The movable contact 38 engages a fixed contact 43 when the carriage 11 is in the position corresponding to pouring (with the core in place in the mold 5-3). The movable contact 39 touches a fixed contact 44 when the mold is closed. For this pouring position, shown on Fig. 6, the current energizes the electromagnet 37 and the plug 34 is lifted. However, when the flowing metal reaches a certain level, it causes an electrical contact between a conductor 45, supplied with a 24 volt current, and a conductor 46 connected to the coil of the switch 42 connected to the line 36. At this instant the switch 42 opens and breaks the circuit supplying the electromagnet 37 and the plug 34 falls back and closes the tap hole.

The arrangement of the electrical system is thus such that the plug 34 cannot be lifted and metal cannot be poured into the mold 3-5 unless the latter is closed (so that the contacts 39 and 44 touch each other), unless the core 17 is in position in the closed mold (so that contacts 38'and'43 touch each other), and unless the pivoting carriage 1, with its abutment 41 has closed the switch 40, so that the mold 3-5 is positioned exactly under the tap hole of the furnace 33.

Lamps or luminous signals 47 may be connected to light up if the contacts 38-43 do not touch each other or if these contacts do touch but the contacts 39-44 do not, by reason of an incomplete closing of the mold 3-5. A sound signal 48 connected to the contacts 38 and 44 sounds at the same time that one of the lamps lights up. The current passing through these lamps and the I Fig. 11 is a diagrammatic view showing the general arrangement of the compressed air system used to control the various air cylinders of the die casting machine described, and the electrical circuits of the electromagnetically actuated valves controlling this system. Reference numerals 49 and 50 indicate the two conductors of an electrical supply line. A motor compressor is fed by this line and supplies compressed air through a principal pipe 52. A rotatable switch 53 is driven through speed varying means by a motor 54, fed by this same line. An electromagnetically actuated valve 55 provides a periodic supply of air to the cylinder 29 which pivots the principal carriage 1. The circuit controlling this valve 55 is opened or closed by, the rotating radial arms 56-57 which act .on the levers 58-59 of a switch integral with the valve 55. At the same time an electromagneticvalve 60 which carries levers 61 and 62 actuated by the rotating arms 63 and 64 respectively provide a periodic supply of compressed air to the cylinder 10, which opens and closes the mold 5-3.

The figurej shows valves 27 and 28, which may be assumed to be electromagnetically actuated, and the circuit controlling which is opened or closed by the earns 25 and 26 as has already been set forth, to actuate the cylinder 13 which moves the carriage 11. Reference numeral 24 designates the switch integral with an electro magnetically controlled valve which controls the supply of compressed air to the cylinder 20 which moves the carriage 18 carrying the ejectors 21.

It is of course within the scope of a man skilled in the art to provide means for regulating the position of the rotating arms 56-57 and 63-64 so as to modify the intervals of time between the opening and closing of the mold and between the pivotal movements in opposite directions of the principal carriage. These arms may, moreover, be replaced by cams or themselves constitute cams acting on sliding contacts.

It is not, moreover, intended that the invention be limited to the specific machine described, since the invention lends itself to several other embodiments. Thus, while only a single axial core has been shown, the carriage 11 may carry a plurality of cores extending perpendicularly with respect to the joint between the mold sections 3 and 5. Auxiliary means may also be provided for supporting cores extending parallel to the mold joint or at a given angle thereto, and means for with! drawing these cores at a convenient time and position.

Finally, the invention is not limited to the system described -for controlling the various movements constituting a given cycle. Any system within the scope of a man skilled in the art may be used, regardless of whether itcomprises quick acting or time delay relays. However, this system will preferably be selected from among those permitting all the conditions of operation to be varied, and in any case it must comprise safety devices serving the same purpose as these which have been described.

What is claimed is:

1. In an automatic die casting machine provided with a sectional mold, a metal holding furnace provided with a tap hole and a plug for closing said tap'hole, electromagnetic means for raising said plug and thus allowing a direct gravity feeding of said mold when it is disposed below said tap hole, means for controlling the movements of said mold and comprising a principal carriage carrying a first section of said mold fixed thereto, said carriage being pivotally mounted on a vertical axle to swing between a filling position beneath said tap hole and an ejecting position horizontally removed from said tap hole, a first auxiliary carriage carrying a second section of said mold and slidable on said principal carriage between a position in which said mold is open and one in which it is closed, automatic means for periodically applying power to swing said principal carriage and reciprocate said first auxiliary carriage between their said positions, a second auxiliary carriage carrying at least one core and slidably mounted on said first auxiliary carriage to reciprocate between a position in which said core projects through a registering hole in said second section of said mold into the interior of said mold and a position in which said core extends into and blocks said mold hole but is withdrawn from the interior of said mold, power means for reciprocating said second auxiliary carriage relatively to said first auxiliary carriage, means positioned on said first auxiliary carriage to actuate the power means for reciprocating said second auxiliary carriage whenever said first auxiliary carriage passed a predetermined point in its path, a third auxiliary carriage provided with ejecting means and slidably mounted on said first auxiliary carriage to reciprocate between an ejecting position in which said ejecting means project into said mold through registering holes therein and a withdrawn position in which said ejecting means is removed from within said mold, power means for reciprocating said third auxiliary carriage relatively to said first auxiliary carriage, means positioned on said second auxiliary carriage to actuate the power means for reciprocating said third auxiliary carriage whenever said second auxiliary carriage passes a given point on its path of travel, a circuit for supplying power to said electromagnetic means and thereby opening said tap hole, a plurality of independent normally open circuit interrupting means in said power circuit, and separate means on said principal and first auxiliary carriages which independently close said interrupting means only when said principal carriage is moved to filling position and said first auxiliary carriage is moved to the position in which said mold is closed, an auxiliary normally closed electromagnetic interrupting means in said power circuit, an auxiliary power circuit for said auxiliary electromagnetic interrupting means, said auxiliary power circuit being normally interrupted, and closed by the molten metal cast in said mold only when said molten metal is at a predetermined level whereby said power circuit is interrupted and said tap hole is closed.

2. Apparatus as claimed in claim 1 in which said principal and first auxiliary carriages are independently actuated by separate power means, and said power meansare periodically actuated through a rotating timer switch.

3. Apparatus as claimed in claim 1 in which the power circuit supplying said power operated tap hole closure comprises additional circuit-interrupting means and said second auxiliary carriage carries means which closes said last mentioned circuit interrupting means only when said core projects into the interior of said mold.

4. Apparatus as claimed in claim 2 in which said principal and first auxiliary power means are fluid pressure cylinders and are operated by electromagnetic valves actuated through said rotating timer switch.

References Cited in the file of this patent UNITED STATES PATENTS

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