US2243835A - Die casting machine - Google Patents

Description

June 3, 1 41. J. BRUNNER ETAL 2,243,835

DIE .IOASTING MACHINE Filed June 10, 1939 IIVVfA/TORS Ad. BRuM/ER dMAr/msss argj fflg of a die casting machine tion, the pneumatic and electricaloperating sys- Patented June 3, 1941 UNITED STATES PATENT OFFICE 2,243,335 ma CASTINGMACHINE Anton J. Brunner, Congress Park, and Bruno M, A.

Trebes,Berwyn, 111., mi trio Company, Incorpor gnors to Western Elecated, New York, N. Y., a 1 corporation of New York Application June 10, 1939, Serial No. 278,386

(cleans) 5 Claims.

'. This invention relates to die casting machines,

and more particularly to die casting machines of the type in which the diecavity is evacuated prior to each casting operation.

Objects of the invention are to provide a simple,

inexpensive and eflicient die casting "machine by 7 means of which substantially non-porous castings having smooth surface finishes may be produced economically and with a minimum amount of manualefiort. 1' l In accordance with the above objects, one embodiment oi the invention contemplates the provision of a die casting machine having means for quickly evacuating the die cavity prior to each preventing the flow of molten metalinto the die cavity during the evacuation of the air therefrom and means for preventing the passage of molten metal into the evacuating systemdurlngthe injection of the metal into the die cavity.

Other features and advantages of the invention will become apparent from the following detailed description when read in conjunction with the accompanying drawing, in which I Fig.1 is a fragmentary vertical sectional view embodying the inventems being illustrated schematically, and v Fig. 2 is a detail sectional view taken on line 22 oi' Fis. 1. I

Referring now to the drawing, the invention is illustrated therein as embodied in a die casting machine comprising a stationary die supporting plate l0 and a movable die supporting member H to which areattached complementary sta tionary and movable-die sections l3 and I4, re-

casting operation, simple and reliable means for l i seen that the piston rod 32 extends through the cam shaft .42.

insure that the molten metal is' maintained at the proper temperature as it passes therethrough.

The charging cylinder 22 is provided near its.

upper end with an inlet port 21 which leads from the melting pot into the interior of the cylinder.

A vertically reciprocable piston or plunger 28 is arranged to operate within the cylinder for forcing the molten metal into the die cavity under the required pressure. The plunger is operatively connected to a vertically reciprbcable piston 30 of an air cylinder 3| mounted above the charging cylinder. From its uppermost position, the piston 30 is adapted tobe moved downwardly a predetermined distance by a vertically reciprocable rod 32 attached to a piston 33 of 'an air cylinder 34 mounted above air cylinder 3|. It will be top of cylinder 3| and is adapted to engage the topof piston 30. An exhaust port 38 is provided in the lower end of cylinder-34 below the piston 33 and the upper end of the cylinderis connected by a pipe 31 to a valve 38, throughwhich high pressure air from a supply line 40 may be delivered to the upper end of the cylinder. The valve 38 is operated by a cam 4lmounted on a cam shaft42. M v

The upper end of' air cylinder 3i is connected by a pipe 43 to a double poppet valve 44, through which the high pressure air may be delivered to the upper end of cylinder 3|. The valve 44 is operated by a pair of cams 45 and 46 mounted on The lower end of cylinder 3| is connected by a pipe to a double poppet valve 49, through which, relatively 1 low pressure air from a supply line may bei'delivered to the lower end of the cylinder. The valve 49 is opspectively. The adjoining faces of the diesec tions'areformed to provide a die cavity I5 oi'the required shape; and the stationary die section I3 is provided with a sprue opening it leading into the die cavity. l

A suitably heated receptacle or melting pot 20 I is provided for containing a supply. of. molten metal to be cast, and a die charging pump H is mountedwithin the pot. The charging Dump comprises a vertically disposed charging cylinder 22 having a goose-neck nozzle portion 23 formed with a discharge passage 24 leading from the bottom of the cylinder. .A connecting nozzle 26 connects the disoharge passage 24 with the sprue opening l5, and it will be understood that this connecting nozzle, as well as the exposed upper end portionof the goose-neck nozzle, may be heated by any suitable means (none shown). to

erated by a pair of cam shaft 42. I i

For sealing the die cavity against ingressof air, an air excluding manifold 5515 provided which comprises complementary sections 56 and earns. 5i and 52 mounted on 5| adaptedto completely: surroundthe die sections I3 and M, respectively. The manifold sections are removably attached to the respective die sections by means of clamping screws 58, 58, and rubber gaskets 59, 59 are interposed between the manifold sections and the die sections to provide air tight seals. The adjacent faces of the manifold sections are provided with cooperating means an air tight seal; therebetween when the die is closed. This means, in the illustrated embodiment of the invention, comprises a rubber gasket 60 in the iaceoi manifold section 51, which is adapted to be engagedby a bead 6| in l the adjacent face of manifold section 56.

When the die is closed, the manifold sections form a chamber 83 surrounding the die cavity and this chamber is adapted to conmiunicate with the die cavity through a narrow connecting passage 65 in the die section 14. A reciprocable shutter 68 is provided for closing the passage 85 to prevent escape of metal therethrough during casting operations.v The shutter is operated by an air cylinder 88 through suitable toggle levers 68. This air cylinder is connected by flexible pipes 1t and 12 to an air valve 13, through which the high pressure air from supply line 48 may be dlelivered to either end of the cylinder. The valve 13 is operated by a cam 14 mounted on cam shaft 42. a

The manifold chamber 83 has an outlet passage 15 connected by a pipe 18 to a valve 11, through which the manifold chamber may be connected to a vacuum pump 18 driven by an electric motor 18. A suitable filter 88 is provided in the pipe line 18 for collecting any metal that may escape accidentally from the die cavity, thus preventing obstruction of the vacuum system.

The valve 11 is operated by a reciprocatory piston 82 mounted above the valve in a cylinder 83 which may be integral with the valve casing. A solenoid operated valve 85 is provided through which low pressure air from supply line 58 may be'delivered to cylinder 83 for operating piston 82 and .thereby the valve 11-. The valve 85 is operated by a solenoid 81 whose energizing winding is connected 'to electric supply lines 88 through two normally open switches 88 and 88 connected in series. Switch 88 is adapted to be closed upon closing of the die by a bracket 81 on the movable die supporting member H. Switch 88 is adapted to be closed by an arm 83 on a rod 84 projecting upwardly from the piston 33 of plunger operating cylinder 34. The switch operating arm 83 is adjustable on rod 84 to effect the closing of switch 89 only upon downward movement of plunger 28 a distance suflicient to close inlet port21. This insures that port 21 is closed before the solenoid operates to connect the die cavity with thevacuum system, thuspreventing the flow of molten metal into the die cavity during the evacuation of the air therefrom.

It will be apparent to those skilled in the art that the cam shaft 42 may be oscillated or rotated in any suitable manner either by power means under the control of a suitable timer or by manual operated means, it being essential only. that the several control valves be operated in the proper sequence and time relation. In the illustrated embodiment of the invention, a hand operated lever 88 is operatively connected to cam shaft 42 through suitable gearing 81 adapted to efiect approximately one-half revolution of the cam shaft upon movement of the hand lever from its neutral or starting position to its final operative position. The valve operating cams, of course, are designed to operate the valves open. The plunger 28 isin its uppermost position, the shutter 86 is in its open position and the valve 11 is positioned so that the die cavity is open to the atmosphere and closed to the vacuum pump. Also, valve 38 is positioned so that the upper end of cylinder 84 is open to the atmosphere and valves 44 and 48 are positioned so that the upper end of cylinder 3| is open to the atmosphere while the lower end of this cylinder is connected to the low pressure air line 58. At this time, the valve 13 is positioned so that it connects the upper end of cylinder 68 with the high pressure air line 48 and opens the lower end of this cylinder to the atmosphere. To operate the apparatus, the die is closed by suitable means (not shown) and the hand lever 88 is moved to the intermediate position shown in dotted outline in Fig. 1. Upon closing of the die, the switch 88 is closed by the switch actuating bracket 8|, thus conditioning the energizing circuit for the solenoid 81. Movement of the hand lever to the intermediate position causes rotation of cam shaft 42 to a position in which cam 4| operates valve 38 to deliver high pressure air from supply line-48 to the upper end of cylinder 34, whereupon its piston 33 is moved downwardly.- The piston 38 of cylinder 3| is thereby, also moved downwardly, thus moving the plunger 28 to the intermediate position indicated by the broken line 88. In moving to this intermediate position, the plunger closes the molten metal inlet port 21 of charging cylinder 22 and elevates the molten metal in the goose-neck discharge rpassage 24 approximately up to the sprue opening 16 of the die, as indicated by the broken memo, thus expelling air from the goose-neck and connecting nozzles. This reduces the time required for evacuating the die cavity, since it reduces the amount of air that must be exhausted. It will be obvious that the movement of the hand lever to the intermediate position also causes cams SI and 52 to operate double poppet valve 48 so as to open the lower end of cylinder 3| to the atmosphere. Upon movement of the plunger 28 to the intermediate position, the switch actuating arm 83 closes the switch 98, thus completing the previously conditioned energizing circuit for solenoid 81, whereupon the solenoid operates valve to connect the upper end of cylinder 83 to low pressure air line 50. The piston 82 in cylinder 83 is thus moved downwardly, whereby the valve 11 is operated to connect the die cavity It with the vacuum pump 18.

It has been found that in some instances satisfactory castings may be produced when the air is expelled from the goose-neck and connecting nozzles by the preliminary movement of the pump plunger, evn though the die cavity is not evacuated. but generally more satisfactory results are obtained when the die cavity is evacuated.

After a. brief interval of time sufiicient for the evacuation of the die cavity, the hand lever is moved to its final operative position and upon movement of the hand lever to this position the valves 13 and 44 areoperated. The valve 13 is operated slightly in advance of valve 44 so as to deliver high pressure air to the cylinder 68 for closing the shutter '66 prior to the injection of the molten metal into the die cavity. Following the closing of shutter 66, the valve 44 is operated to deliver high pressure air to the upper end of cylinder 3|, thus causing further downward movement of piston 38 and thereby the plunger 28,-whereby the molten metal is forced into the evacuated die. The hand lever is then returned to its original or starting position, whereupon all of the parts are returned to their original or "at rest" positions and the casting is removed, thus completing one cycle of operation of the apparatus.

It will be obvious from the above description that a simple and inexpensive arrangement is provided for quickly evacuating the die cavity prior to each casting operation and that simple and reliable means are provided for preventing the flow of molten metal into the die cavity during the evacuation thereof and for preventing the escape of molten metal from the die cavity during the casting operation. It should be understood, of course, that the invention is not limited to the particular embodiments thereof herein illustrated and described, except insofar as is defined by the appended claims.

What is claimed is:

1. In a die casting machine including a die having a casting cavity, a die charging means comprising a charging cylinder having an inlet port for material to be cast and a discharging passage communicating with said die cavity, a reciprocable plunger in said cylinder, means for imparting an intial movement to said plunger to close said inlet port and advance the castingmaterial into said discharging passage and-thereby expel the air therefrom, means actuated by said plunger moving means upon the completion of said initial movement for evacuating said die cavity, and means for thereafter imparting further movement to said plunger to forcibly inject the casting material into the evacuated die cavity.

2. In a die casting machine including separable die members, oneof which is movable for opening and closing the die, a die charging means comprising a receptacle for material to be cast, a charging cylinder in said receptacle having an inlet port below the surface of said material, said cylinder having a discharging passage communieating with said die, a reciprocable plunger in said cylinder, means for imparting an initial movement to said plungerto close said inlet port, means rendered effective automatically by said movable die member and said plunger moving means upon movement of said movable die member to closing position and movement of said plunger to port closing position for evacuating the die, and means for thereafter imparting further movement to said plunger to forcibly inject the casting material into the die.

3. In a die casting machine including a die having a casting cavity provided with an air outlet passage and an inlet opening for material to be cast, a die charging means comprising a charging cylinder in constant communication with said die cavity through said inlet opening, said charging cylinder having an inlet port for material to be cast, a reciprocable plunger in said cylinder, means for imparting an initial movement to said plungerto close said inlet port, means rendered effective automatically by said plunger moving means upon the completion of said initial movement for evacuating the die cavity, and means for thereafter imparting further movement to said plunger to forcibly inject casting material from said cylinder into the evacuated die cavity.

4. In a die casting machine, complementary die members cooperating to provide a die cavity, one of said die members being movable to open and close said cavity, a charging cylinder having a discharge passage communicating with said die cavity, a reciprocable plunger in said cylinder, reciprocatory means movable in one direction for imparting a relatively slow initial move ment to said plunger to advance the casting material through said discharging passage to expel the air therefrom, and die cavity evacuating means rendered eiiective automatically by said movable die member and said reciprocatory means upon movement of the movable die member to the closed position and movement of said reciprocatory means a predetermined distance in said direction.

5. In a die casting'machine, complementary die members cooperating to provide a die cavity, one of said die members being movable for opening and closing said cavity, a charging cylinder having a discharging passage communicating with said die cavity, a reciprocable plunger in said cylinder, reciprocatory means movable in one direction for imparting a relatively slow initial movement to said plunger to advance the casting material through said discharging passage to expel the air therefrom, means for evacuating the die cavity, electromagnetic means for controlling said evacuating means, an electrical energizing circuit for said electromagnetic means, two normally open control switches connected in series in said energizing circuit, means for closing one of said switches upon movement of said movable die member to the closed position, and means for closing the other of said switches upon movement of said reciprocatory means in said direction.

ANTON J. BRUNNER. BRUNO M. A. TREBES.

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