US1639253A - Centrifugal casting appliance - Google Patents

Description

L. W. AYERS CENTRIFUGAL CASTING APPLIANCE Aug. 16, 1927.

Filed Jah 1x Patented Aug. 16, 1927.

UNITED STATES PATENT OFFICE.

CENTRIFUGAL CASTING` APPLIANC.

Application led January 29, 1924. Serial No. 689,270.

This invention relates to `appliances for producing metal casts in which great accuracy as to structural conformation is required; and an object of the invention is to 6 provide a means for producing delicate casts that are Substantially true to the conformation -of the mold.` j v To'that end I provide an appliance' with a speed control that will discharge the Ametal from its crucible into the mold by a centrifugal force the intensity of which is predeter mined; and which force is maintained at a uniform intensity until the metal cast has hardened and cooled; thereby preventing the cast from shrinking away from the mold Wall as`it is cooled. In other words, I rotate the appliance at a predetermined and uniform speed so that the metal from the crucible will be driven into the mold and .held there by centrifugal force until it is thoroughly cooled; and the uniform centrifugal force applied tothe metal will tend to hold it in contact with the mold Wall While cooling so that shrinkage away from the wall is 25 minimized. n

` Heretofore centrifugal 'appliances of this class have been devised that at the first moment of casting have been actuated at a high speed that quickl loses its momentum and decreases in spee to a stop; and usually the stop occurs just at the critical time when the metal is starting to cool and ofttimes in a position in which the cast will shrink away suiiiciently from the wall to make it undesirable and-ill shaped; and an object of my invention is to provide a means for maintaining centrifugal force on the cast until it yhas thoroughly hardened and cooled.

An object of the invention is to provide a centrifugal appliance that can be detachably connected to the shaft of a speed controlled motor such as are commonly used by dentists7 jewelers and tine metal workers; so that by regulating the motor speed the casting appliance can be operated at a known and uniform speed. 1 i

Another object is to 'provide an appliance that is easily adj listed to a position for melting and discharging the limpression forming pigment such as wax from the mold; and also adjusting it to a position for chargingv and heating the metal 1n the crucible,'which adjustments to the two positions are accomplished by quarter rotations of the motor shaft. c

Another object of the invention is to provide a centrifugal casting appliance with an electrical heater connected thereto that is adapted to melt the impression formingpigment such as wax from the mold; and to 6o dry the mold and harden the composition of which the mold is formed, and also to heat the mold so that the casting metal will more readily enter therein and contact with the wall thereof. Another object of the invention is to provide an appliance that is easy to construct, assemble and operate; and which is also strong and durable in construction, and which can be made and sold cheaply.

Features of the invention are shown in the construction, combination and arrangement of the parts whereby an appliance that is easily adjusted, operated and of great utility is provided. 75

Other objects, advantages :ind features of invention may appear from the accompanying drawing` the snbjoined detail description and the appended clai1n The accompanying drawing illustrates the 8o invention.

Figure 1 is a side View of a motor with a centrifugal casting appliance that is constructed in accordance with this'invention attached to the motor shaft, and showing the 85 appliance in a position to heat and dry the mold; and also showing a side plate removed from the motor casing to disclose one mem. ber of the motor speed control,l

Fig. 2 is a `right end vieivof the motor 90 shown in Fig. l, showing the appliance turned on the shaft to a position to receive the molding metal.

Fig. 3 is an enlarged fragmental section on line, Fi 1, showing the appliance' -turned on the s aft to the position shown in on line Fig. 3, with the a pliance turned on the shaft to the position s Aown in Fig. 1. Fig. is a central section through the mold casing showing a fusible inla embedded in the'mold forming materialI with a bore formin pin attached thereto.

Fig. 6 is a vlew analogous to Fig. 5, with the bore forming pin detached; and showing the fusible inlay melted out of the mold.

Fig. 7 is a cross section o n line w", Fig. 4. Fig. 8 is a cross section on line w8, Fig. 4. Figi 9 is a broken detached side View of the centrifugal arm.

Fig. 10 is a perspective view of the housing and associated parts detached from the centrifugal bar.

The centrifu al casting a pliance 1 com` rises a bar 2 t at is provi ed with anlorice 3 that is adapted to be fitted over and secured by a-screw 4 to a shank 5 on a chuck 6, that is adapted to be connected to a shaft 7 on -the motor 8. v f

The motor 8 is ofwell known construction preferably having a speed range'of about 1000 to 3600 revolutions per minute with a control switch 9 of usual construction for regulating the speed.

The speed control and operation of the motor are 'well known and are therefore not shown and described in detail, except to state thatthe speed of the motor can be con-` f and the other end threaded for the nut 15,

by which means the housing 14 is adjustably secured'to the end 10 of the bar 2. The housing 14 is provided with an integral annular s acing ring 16 that extends inwardly towar .the axis of the housing 14; and th1s ring1 forms a seat for an insuinto Ithe housing 14 and secured therein by an inner cylindrical housing 18 that at one end is: threaded to t the threaded end of the housin 14, and which has its other end ittin ilus within'the inner surfaces of the ann ar ring 16. A

The heating coil 17 is adapted to be placed in circuit with a source of electricity, not shown, b means of the lead wires 17 and detachab e 19 adapted tok be fitted to a lu socket in. the oss 20 extending from the housing 14. A crucible casing 20 is shrunk in the inner housing 18; and this casing is provided with :xv-cylindrical metal lining shell 21 which at tted the eating; coil 17 that is fitted o ne end is provided with an inner annular ring 22 that forms a retainer for the noncombustible' material 23 of which the crucil' 1, 2 and 4, and engages the mold cylin er i A mold 28 is formed by embedding a'fbody 29 that fuses at a low temperature in investment 30 that is poured into the cylinder 26 around the body that is supported on a pin 31 that when withdrawn from the investment 30 forms a small lead hole to the mold 28.

Preferably the body 29 is formed of wax and the pin 31 is set therein as shown in the drawing so that when the Casin 26 is seated. and secured in the shell 21 and t e appliance turned to the positions shown in Figs. 1, 4 the heating coll 17 can be ener 'zed to melt the wax in the mold 28 so t at both theV wax and pin 31 will fall by gravity to empty the mold and clear the lead hole thereto; and

the heater 17 can be continued in operation until the mold 28 and cement are dried and v hardened.

speed to drive the molten metal 32 by cen-` trifugal force into the mold 28;. and the predetermined speed of the motorcan be uniforml maintained until the metal has coole in the mold.

A ball' 33 is threaded'so it is adjusted on the threaded end 34 of the bar 2 so that a balance can be established ,between the ball and the casting appliance at the other end of said bar.

In practice, the applianceis operated as stated to' heat the mold so that the metal will more readily enter therein and contact to the mold wall,and byv centrifugal means the metal isforced and held against the mold wall until both the metal and mold have cooled, thereby forming a cast of su erior conformation.

claim: g

A centrifugal casting'appliance set forth comprising a bar having one of its end portions flattened and the other end rounded and threaded, a balance ball threaded on said threaded end, said attened 'end having a slot formed therein, a. housing ad'ustably mounted in said slot; an inner ousin Within said housing and spaced therefrom;

Y electrical coils between said inner and outer housings, a detachable electricalv connection to said coils, 9, Crucible said inner housing, al crucible in one end ofsaid Crucible casing, a; mold cylinder removably mounted in said crucible casing, and means 10 to rotate said bar around an axis,

In testimony whereof, I -have hereunto set myhand at Los` Angeles, California, fhis'l23rd day of January, 1924.'

LOREN WILLIAM AYRS.

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