US1751846A - Casting machine - Google Patents

Description

A. L. WILKES CASTING MAQHINE March 25, 1930.

Filed April 50, 1928 Patented Mar. 25, 1930 UNITED STATES ALFRED L. WILKES, F LOS ANGELES, CALIFORNIA c'AsgING MACHINE Application led April 30,

x Ihis invention has to dowith a casting machine, andit is a general object of the invent1on to provide an improved, effective and practical machine operable to cast material at spredetermined temperatures.

The machine provided by this invention is particularly suited for casting metals or al- -loys in cases where definite casting temperatures are important. For example, the machine is especially suited to casting gold 0r gold alloys such as are used in dentistry.

For the purpose of facilitating an understanding ofa simple form and application of the invention, I will refer to it as it is related-to the casting of gold and gold alloys for dental purposes,'it being understood that such reference is not to be construed as limiting the broader principles of the invention.

In the making of gold or gold alloy parts for dental purposes it is customaryto prepare a mold or impression of the part to be formed and then cast the metal into the mold. Various types of apparatus have Vbeen devised for use in makingv such castings, it having been found that the centrifugal type of casting machine is well suited to this class of work.y The molds are usually made of plaster, the impression beingl formed by embedding a wax, or similar image of the object, 1n the plaster to be burned out after the plaster has set. Several grades of gold and different gold alloys have have been developed for dental use, it having been found that different grades of gold or various gold alloys of gold have various characteristicsand that some are better suited for certain purposes than others. It is also true that a given gold or gold alloy cast at different temperatures will have different characteristics, there being an ideal casting point for each particular alloy or grade of gold.

It is an object of my present invention to provide a casting machine by which castings can be made at known temperatures, thus making it possible to obtain uniform and correct castings.

It is another object of this invention to provide a casting machine of the character mentioned which is suitable for practical or 50 general use and is simple to operate.

-be obtained.

1928. Serial No. 273,980.

A further object of the invention is to provide a casting machine of the character mentioned, arranged and constructed so "that the exact temperature of the'molten metal can The various objects and features of my invention will be best and more fully understood from the following detailed description of a typical form and application of the invention, throughout which description I refer to the accompanying drawings, in which:

Fig. 1 is a side elevation of a casting mav chine of the centrifugal type embodying the present invention. Fig. 2 is a plan view of the machine being a view taken as indicated by line `.2--2 on Fig. 1. Fig. 3 is a detailed sectional View taken as indicated by line 3-3 on Fig. 1 showing a detailed construction that may be used in carrying out the invention. Fig. 4 is an enlarged detailed sectional 70 view taken as indicated by line 4 4 on Fig. n. Fig. 5 is a diagrammatic vievT illustrating the electrical circuits included in the device.

yMy present invention provides, generally, a casting machine in which there is a cupola 10, a mold 11 in communication with the cupola to receive molten metal therefrom, a thermo couple 12 located at or in the .cupola to be subject to the same -heat condltlons as the metal in the cupola, and an indicating instrument 13 electrically connected with the thermo couple 12.

In the present disclosure I have chosen to set forth a centrifugal casting machine and therefore the cupola 10 is shown mounted on an arm 14 projecting radially from a spindle or rotor 15 driven by a spring motor' 16, or the like.- The arm 14 and the cupola 10 with its connected parts are counter balanced by 9o an arm 17 and a weight 18 which also serves as a handle by which the rotor lcan be conveniently turned to wind the motor 16. 'Iohe motorl is provided with a suitablehouslng which also forms a base for the entire mao5 chine.

In the arrangement illustrated, the roter is'controlled by a lever 19 pivotally mounted on the exterior of the motor housing. The control lever 19 is designed to cooperate with 100 a notch 20 in the periphery of a iiange 21 projecting from the rotor. When the motor is wound the control lever is engaged in the notch 2O where it will remain until operated in the direction indicated by the arrow in Fig. 2. When the control lever is operated so that it is released from the notch the rotor is released and is driven by the motor.

The cupola 10 may be of any suitable formation. For instance, it may be the ordinary open type of cupola used in casting machines of this character. In the drawings I have shown the cupola as comprising a metal case 21a provided with a lining 22 of fire clay, or the like, shaped to form a cup-like depression A for carrying the metal to be cast. The depression A of the cupola is in communication with an opening 23 in the case of the cupola, the opening 23 being provided to pass the molten metal when the machine is operated.

The mold 11 illustrated in the drawings is of a type commonly used in making castings for dental purposes and comprises a `metal case 24 carrying a body 25 of plaster, or'the like, in which there is a cavity or opening B for forming the metal. Thecavity B in the mold is Vin open communication with the opening 23 in the casing of the cupola so that the molten metal passes directly from the cupola into the mold when the machine is operated.l In practice the mold is formed separate from the cupola and is releasably clamped in operating position through a suitable clamping device 26.

The thermo couple 12 provided by my invention is located in or at the cupola so that it is subject to the same heat conditions as the metal in the depression Aof the cupola. In the preferred form of the invention, the thermo couple 12 is located Vin the bottom of thedepression A of the cupola and is, in fact, mounted to project into the depression A. `I have coated or protected the thermo couple with a body 30 of alundum so that it is not oxidized or amalgamated with the metal in the cupola. Wires 3,1 and 32 extend from the thermo couple 12 through the lining 22' of the cupola. One of these wires is grounded, for instance is connected to the rotor 15, or a suitable part of the machine, so that it is grounded with the machine, while the other is maintained out of electrical connection `with the other parts of the machine.

The instrument 13 provided by my invention operates to indicate the electrical condition of the circuit in'which the thermo couple is connected. The indicating instrument 13 ispreferably located at a point remote from the machine. With this arrangement one of the wires from 'the thermo couple, for instance the wire 31fwhich is grounded to the machine, is connected with the instrument by a wire 318L which is connected to the machine and extends to the instrument. The

other, or insulated wire 32 from the thermocouple, is connected to an insulated contact ring 35 mounted on the'flange 21 of the rotor. A brush 36 is mounted stationary on the motor case through suitable insulation and engages the ring to establish an electrical connection therewith. A wire 32a connects the brush 36 with the other terminal of the instrument 13.

The instrument 13 may be of any suitable constructionk operable to indicate the electrical condition of the circuit in which the thermo couple is connected. The instrument preferably includes an indicating hand 40 and a dial or scale 41 with 4which the hand cooperates to give a reading of the electrical condition of the circuit, it being preferred that the hand and scale cooperate to give such reading directly in degrees of temperature.

My present invention further provides an automatic control for the motor adapted to be set to release the motor when the metal in the cupola has reached a predetermined temperature. In `the drawings I have illustrated an arrangement wherein there is an electromagnet 50 mounted on the motor case and connected with the control lever 19. The winding of the electromagnet is connected in a circuit carried by wires 51 and 52 and energized' by suitable source of power, such as a battery 53. y A contact device is connected inthe wire 51 at the instrument 13 to be operated by the instrument. The contact device illustrated includes a body or carrier of insulating material havin two spaced cup depressions 71 carrying bo les or globules 72 of mercury. The carrier 70 is mounted at the scale 41 of the' instrument so that the globules of mercury 72 are in the path of the indicating hand 40. The globules of mercury are connected in the line'51 so that the circuit is closed or completed through the indicating hand 40 when the hand is in contact with both globules of mercury. The carrier 70 is adjustably mounted so that the-circuit may be closed at the desired predetermined point of operation of the instrument. y

In the drawings I have shown the carrier mounted in a guideway 74 extending parallel In the preferred construction, a guide or rest is provided on the motor case, to clear or be out of the path of the revolving parts 'of the machine.v The rest may be used to support or guide a torch, or the like, that may be used in melting' the metal in the cupola.

' Without the guide 80 an operator might have the torch in position to be struck by the moving parts of the machine when the machine automaticallyoperates. It is to be understood, of course, that the machine can be operated by the automatic control above described or can be manually ope 'ated by the simple operation of the lever 19. f

Having described only a typical preferred,

form of my invention, I do not Wish to limit myseltl to the specific details set forth, but wish to reserve to myself any changes or variations that may appear to those skilled in the art or fall within the scope of the followinlr claims.

Iaving described my invention, I claim:

l. In a'casting machine a receptacle for the material to he cast, a mold to receive the material, operating means for causing the material to discharge from the receptacle'to the mold, and a control for the operating means whereby it operates upon the material reaching a predetermined temperature, the control including a thermo-couple at the receptacle,

an ,electro-magnetic unit in connection with' the operating means and a contact device electrically connected to the thermo-couple and operable to cause encrgization of the unit. Y

2. In a casting machine a receptacle for the material to be cast, a mold to receive the material, operating means for causing the material to discharge from the receptacle to the mold including a motor for rotating the receptacle, and a control for the lnotor Whereby it operates upon the material reaching a predetermined temperature, the control including, a thermo-couple at the receptacle, an electro-magnetic unit to release the motor for operation, and a contact device electrically connected with the unit upon the material reaching a predetermined temperature.

3. In a casting machine a receptacle for the material to be cast, a mold to receive the ma.- lerial, operating means for causing the material to discharge from `the receptacle to the mold, including,vv a motor for rotating the receptacle, and a control for the motor Whereby it operates upon the material reaching a predetermined temperature, the cont-rol including a thermo-couple, an indicating in- /strument electricallyT connected with the thermo-couple, an electro-magnetic unit to release the motor, and a contact device operated by the instrument to engage the unit.

4. In a casting machine a receptacle for the material to be cast, a mold to receive the material, operating means for causing the material to discharge from the lreceptacle to the mold, including, amotor, and acontrol for the operating means whereby it operates upon the material reaching a predetermined te1n.

pera-ture, the c ontrol including a thermo couple, an mdicatlng instrument electrically connectedA with' the thermo-couple, an electromagnetic unit to release the motor for operation, and an adjustable contact device operated by the instrument to energize the umt.

'5.' In a casting machine a receptacle for the material to be-cast, a mold to receive the material, operating means for causing the material to discharge from the receptacle to the mold, and a control for the operating means whereby it operates upon the material reaching a predetermined temperature, the control including an electro-magnetic unit in connection with the operating means, a thermo-couple at the recept-acle, an indicating instrument in circuit with the thermo-couple, anda contact devicev controlling the unit and operated by the instrument.

6. In a casting machine a receptacle for the material to be cast, a mold to receive the material, operating means for causing the material to discharge from the receptacle to the mold by centrifugal action, and a control for the operating means -whereby it operates upon the material reachinga predetermined telnperatule, including, a. thermo-couple at the receptacle and an electro-magnetic unit electrically connected with the thermo-couple operable to release the operating means.

7. In a casting machine a receptacle for the material to be cast, a mold to receive the material, operating means for causing the material to discharge Jfrom thereceptacle to the mold, including a spring motor operable to rotate the receptacle, and a control for the operating means whereby it operates upon the l material reaching a predetermined temperature, including, a thermo-couple at the receptacle, an indicating instrument electrically connected with the thermo-couple, an electromagnetic unit operable to release the motor, and a contact device controlling the unit and operated by the instrument.

In Witness that I claim the foregoing I have hereunto subscribed my name this 24th day of April, 1928.

' ALFREDL. WILKES.

Aso

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