US2220776A

US2220776A - Pressure casting apparatus

Info

Publication number: US2220776A
Application number: US283586A
Authority: US
Inventors: James N Smith
Original assignee: Aluminum Company of America
Current assignee: Howmet Aerospace Inc
Priority date: 1939-07-10
Filing date: 1939-07-10
Publication date: 1940-11-05
Anticipated expiration: 1957-11-05

Description

Nov. 5 1940.

J. N. SMITH PRESSURE. CASTING APPARATUS Filed July 10, 1959 2 Sheets-Sheet '1 INVENTQR. James A! 5/27/71? Patented Nov. 5, 41940 UNITED STATES 2,220,776 PRESSURE CASTING APPARATUS- James N. Smith, Westfield, N.

J assignor to' Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application July 10, 1930, Serial No. 283,586

2 Claims.

This invention relates to pressure casting machines, and more particularly to pressure casting apparatus designed to inject molten metal into a mold cavity formed by separating dies.

5 In pressure casting apparatus the mold cavity is ordinarily formed by. a fixed die and a movable die mounted on a fixed platen and a movable platen respectively, the movable die being adapted to cooperate with the fixed die to form the mold cavity when moved into contact with the fixed die. After a casting is made in the mold cavity, the movable die is withdrawn from the fixed die, and the casting is removed. In order that castings produced in the apparatus may have the desired form, and also in order that the dies may Open and close properly, it is essential that the dies be maintained in. proper alignment while they are in a closedposition, and also during the opening and closing movements of the movable die.

Because of the pressures required to close and open the dies, and the pressure within the mold cavity due to theinjection of molten metal, forces of considerable magnitude are set up which may upset the alignment of the. dies if those forces are permitted to be transferred to the means provided for aligning the dies, and this is particularly true when those forces are relatively high, as in machines applying pres- 80 suresof between 1500 pounds per square inch to 10,000 pounds per square inch on the molten metal in forcing it into the mold. Any deformation-in the means for supporting and aligning the dies as a result of such forces tends to inter- 85 fer e with the alignment of the dies, and consequently is to be avoided. It is an object of this invention to provide pressure casting apparatus in which the dies are maintained in proper alignment at'all-times. re-

,40 gardless of the magnitude of the forces created by opening and closingthem or by the injection of molten metal into the die cavities. It is a further object of this invention to provide pressure casting apparatus in which forces created by the process of filling the mold cavities, are absorbed independently of the means for aligning frame I andpositloned thereon by the guides I0 the dies. 7

It is a further object of this invention to prov vide pressure casting apparatus in which the dies and the means for actuating'the movable die are mounted on a machine frame, and the alignment of the dies is unafi'ected by the forces created by opening and closing the dies or those resulting from the process of filling the mold cavities.

It is a further object of this invention to provide pressure casting apparatus in which the means for actuating the movable die to move it to and from a locking position with the fixed die are slidably mounted on the means for aligning 5 the dies, and are connected to the fixed platen,- which supports the fixed die, by tension members adapted to absorb independently of the diealigni'ng means substantially all of the stresses created by closing and opening the dies and those 10 resulting from the process of filling the mold cavities. I I

Other objects of the invention will be apparent from the following specification and claims, and from the accompanying drawings, in which: 115

Fig. 1- is a side elevation of a pressure casting machine constructed-in accordance with my invention;

Fig.2 is a plan view of the pressure casting machine shown in Fig. 1; and

Fig. 3 is a vertical section takenon the line III-III oi Fig. 1;

Referring to the drawings, the machine frame I, consisting of a pair of parallel channel. members, supports the fixed platen 2, which is bolted 25 or otherwise fixedly attached 'to the machine frame I and carries the fixed die 3. The movable die 4 is carried by the movable platen 5, which is movable on the machine frame I toward and from the fixed die 3, the machine 30 framel serving to align the dies.

- Means for moving the movable die 4 to and from a locking position with the fixed die 3 are provided in the form of a hydraulic cylinder 6, carried by a support I, which cylinder is adapted 35 to reciprocate a rodB having one end attached in a boss 9 at the rear of the movable platen 5. It is to be; understoodv that other conventional means for reciprocating the movable platen may be substituted for the hydraulic cylinder 6 and o r therod 8. Likewise, a suitable-toggle mechanism maybe carried by the support 1 and connected to the movable platen 5 for moving the movable die 4 against the fixed die 3, in which case the rod 8 operates the toggle mechanism, rather than 5 being attached directly to the platen 5. .The support I, is mounted on the machine longitudinally thereof.

legs of the support I. The above-mentioned apertures in the tension members are preferably just large enough to accommodate the pins I2 and [2' without permitting play between the pins and the tension members. The tension members :3 should be strong enough to absorb the stresses created by operation of the movable die 3 and by the injection of metalinto the dies, and may be adjustably mounted in order to control the amount of fiexure desired: The locking plates M, which are remov'ably attached to the sides of the tension members It, cooperate with a groove it in each of the pins l2 and i2 to hold the tension members it in place on the pins. .With the C-shaped tension members'described, the dies 3 and i are intermediate the points at which the tension members it are attached, yet the tension members do not cross the space occupied by the dies, and consequently do not interfere with the dies or obstruct access to them. A receptacle it, having an aperture ll therein to permit molten metal to be poured into the re,- ceptacle, is carried by the fixed platen 2 and communicates, by means of a sprue in the fixed die 3, with the mold cavity formed by the dies. A plunger I8, actuated by the hydraulic cylinder I9 is adapted toreciprocate in the receptacle It to force molten metal from the receptacle l6 and into the mold cavity.

The hydraulic cylinder 5 and the rod 8 are arranged with respect to' the support i and the i movable platen to exert on the su port 7 substantially only forces paralleling the upper surface of the machine frame I longitudinally there-- of during the opening and closing of the dies and during the period of injecting the molten metal. 45 The support I being slidably mounted on the machine frame I, as described above, all longitudinal stresses imparted to the support l are absorbed by the tension members I3; and since substantially no stresses other than longitudinal 5Q stresses are created by the closing and opening of the dies and the procedure of injecting the molten metal, substantially no stresses are imparted to the machine frame I by the operation of the machine which would tend to deform the 55 machine frame and throw the

dies

3 and 4 out of alignment. The tension members l3 may spring or distort without in any way deforming the machine frame or otherwise affecting the alignment of the dies.

The above-described apparatus operates as follows;

Beginning with the

dies

3 and 4 separated, the movable die dis moved toward the fixed die 3 by the rod 8 until' the dies are pressed tightly 65 together, as shown in the drawings. Molten metal is then poured into the receptacle l6 andinjectedinto the mold cavity by means of pressure exerted on the metal by the plunger l8. When the metal in the mold cavity has solidified,

the movable die 6 is retracted to its original position, and the casting is removed from thedies. The forces created by the opening and closing of the dies, and those created by injecting the metal into the dies, are absorbed by the tension members I3, and as a result of the support I being slidably mounted on the machine frame I, are not transmitted to the machine frame, but only to the tension members.

Although the invention has been described with reference to a machine in which the receptacle from which the molten metal is forced into the mold cavity is horizontally disposed, it may also be embodied in machines of the type employing a vertical receptacle and a vertically reciprocating plunger. Likewise, it may be embodied in machines employing pneumatic pressure to inject the metal into the mold. Also, the support for the die actuating apparatus may be held in alignment with the machine frame by means other than guides of the type illustrated on the bottom of the support.

The references herein to the metal to be cast as molten metal will be understood to include metal in what is sometimes referred to as a pasty condition, 1. e. the condition obtaining when the metal is very close to its melting point.

I claim: 1. In pressure casting apparatus including a fixed platen, a fixed die carried by said platen,

a movable platen, a movable die carried by said movable platen, means for-aligningsaid dies, said fixed platen and said. movable platen being mounted on said aligning means; die-actuating meansfor moving said movable die to and from a locking position with said fixed die, said die-actuating means being slidably mounted on said aligning means, and means connecting said fixed platen and said die-actuating means, and separate from said aligning means, for absorbing forces created by opening and closing 'said dies and'by injecting molten metal into the dies, said connecting means comprising at least one C- .fixecl platen and said movable platen being mounted on said aligning means; die actuating means for moving said movable die to and from a locking position with said fixed die, said die actuating means being slidably mounted on said aligning means, and means connecting said fixed platen and said die actuating means, and separate from said alignment means, for absorbing forces created by opening and closing said dies and by injecting molten metal into said dies, said connecting means comprising at least one C shaped member, and said dies being disposed intermediate the arms of said member, the portion of said c-shaped member intermediate the arms thereof being below substantially the lowermost surface of said dies, and the arms of said 0-