US1055343A - Apparatus for casting. - Google Patents

Description

Patented Mar. 11, 1913.

UNITED STATES PATENT oEEIoE.

FRED LLOYD MARK, CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

THE RANSOM & RANDOLPH COMPANY. OF TOLEDO, OHIO, A CORPORATION OF OHIO.

APPARATUS FOR CASTING.

Specification of Letters Patent.

Patented Mar. 11, 1913.

Application filed December 23, 1907. Serial No. 407,726.

. metals is greatly facilitated.

A further object is the production of an apparatus by means of which metal castings, such, for instance, as those intended for fillings for dental cavities, may be quickly formed in proper condition for immediate insertion within the cavity.

A further object is the production of an apparatus by the utilization of which the castings formed will have a greater density than those heretofore formed by the ordinary process, and at the same time will more accurately follow the intricate configurations of the mold.

A further object isthe utilization of a vacuum in the production of metallic cast- 1n i further object is the production of a device that can be cheaply constructed, easily operated and one that is not liable .to disarrangement of parts.

These and such other objects as may here inafter appear are attained by my devic embodiments of which are illustrated in the accompanying drawings, in which the figure represents a side elevation of my device, which includes a sectional view through the center of the flask.

Like numerals of reference indicate like parts in the figure of the drawing.

Referring now to the drawing, 3 represents a vessel air tight, with the exception of an opening 4 in which is fitted a connection 1n the form of a cross 5. A valve 6 terminating in a nozzle 7 communicates with one side of the cross, and a similar valve 8 isconnected with the o posite side of the cross from which exten s a tube 9 havin an upwardly turned elbow 10. Seats upon the top of the connection or elbow 10, and in open communication therewith, is a circular flask support 11 the sides of which taper upwardly, as clearly shown in section. Seated within this flask sup port is a frusto-oonical flask 12, adapted to fit closely against the inner periphery of the support 11. Extending upwardly from the top of the cross 5 is a tube 13 communicating with a vacuum gage 14; while connected to the nozzle 7 of the valve 6 is a tube 15 communicating with an ordinary air pump not shown. It will thus be seen by closing the valve 8 and opening the valvefi the operation of the air pump, not shown, will create a partial vacuum within the chamber of the receptacle 3; When this pressure has reached the desired degree, as indicated by the gage 14, the valve 'is closed. When it is desired to utilize this device in the making of small castings or inlays such as are used by dentists for filling dental cavities, the flask 12 is filled with investment material 16, and a pattern formed from wax or some similar material of the exact configuration of the desired casting. This pattern may be held in lace by a sprue former of similar material: or an ordinary sprue former may be employed and removed before subjecting the flask and contents to the action of heat. The top of the investment material is hollowed out, forming a cup, which, after the removal of the sprue former, or after the absor tion of the pattern and sprue former, by eat in the. body of the investment material, is in open communication with the mold cavlty 18. The flask is then in condition to be placed within the flask holder 11, and the material from which the inlay or casting is to be formed, and which is shown as 19, may be placed in the cup. This may be poured therein in a molten condition, or may be placed within the cup and melted therein by the'use of a blow pipe, or any other similar contrivance.

As soon as the material from which the casting is to be formed is in a suitable molten condition, the valve 8 is opened, and the vacuum chamber 3 put in direct communication with the interior of the flask. This-forces the molten material through the sprue channel 20 and into the mold cavity 18. It may he often necessary when the flask is large, or conditions so demand, to place in the upper portion of the investment material a layer 21 of denser material. Of course, it is understood that the sprue channel passes through this material, and in this construction there is very little opportunity for air to be forced through the denser portion, consequently when the valve 8 is opened and the atmospheric pressure forces the gold or material from which the casting is to be made through the "sprue channel, very little, if any, air will be forced through the impervious layer, but the pressure will follow the material down the sprue channel and'force it into all the interstices w of the mold, thus forming a dense and homogeneous casting.

It will be noted that the flask and flask holder are frusto-conical, or'slightly tapering' upwardly. I find, this quite an important feature, for by means of it the flask'is more closely fitted within" the holder and at the same time the investment material is less liable to crack away from the inner surface ofthe flask after being subjected to the intense heat necessary to melt .out the pattern, and in melting the material from which the casting is to be formed. In this con-v nection there is considerable advantage in the factthat the flask holder and flask while rigidlysupported from thevacuum tank or reservolr are offset so as to leave a considerable clear space around and beneath the flask and flask holder.for the accommoda 'tion of the burner which is used to heat the flask prior to the operation of casting.

I find in practice in the manufacture of small inlays or castings that, it isunnecessary to use any layer of denser material, the investment material itself forming suflicient resistance to the introduction of the air, so that the greater force is applied on the metal through the spine channel.

As noted above, my device is peculiarly adapted for the manufacture of inlays for dental use, and the complete operation is as follows: The dental cavity is first put in condition for filling in the ordinary manner,' care being taken that'there are no reentrant cavities or recesses formed, as it is necessary to insert the filling from without. The Wax or absorbent material from which the pattern is formed is then forced into the cavity. The result of the pattern will, of course, conform exactly to t-heshape of the 59 cavity, and can then be lifted or drawn'out.

After the inlay has been cast, the interior of the dental cavity is coated with a cement and the inlay pressed in place.

It has been found that fillings so constructed and so put in place are much more durable than those filled by the old process.

Under the old system of forcing amalgam into a cavity, or of hammering gold therein, air spaces are often left between the maea terial and the inner walls of the cavity, with a consequent liability to a further decay of the teeth. By the use of my device, however, the filling exactly conforms to the cavity filling and no interstices are left. So, also in the operation of filling the teeth,.

as. the casting of small articles from precious metal, and even the castingof large articles from steel, brass, aluminum, or other materials. Of. course, various modifications and changes. in the apparatus and use will occur to the individual operator,-but they will all come within the limits of my invention, which is the utilization of vacuum with the consequent atmospheric pressure in the casting of metal.

I claim:

1. In combination, a vacuum reservoir tank,and flask supporting means carried directly upon said tank and by the tank alone, said flask supporting means being connected with the interior thereof by means of a ,valve controlled passageway.

2. In combination, a flask, vacuum producing means connected with said flask, a mass of porous material having a cavity therein disposed in said flask, and a layer of material of greater density associated with said porous mass in position to separate the vacuum producing means from the atmosphere, there being a sprue through said porous mass and said denser layer to said cavity.

3. In combination, a mass of porous material having a cavity therein, one side of said mass being exposed, a vacuum chamber connected with theother side ofsaid mass,

and a layerof material-of greater density associated with said firstnamed side of said mass to separate it from the atmosphere, there being'a sprue through said mass and said denser layer to said cavity.

4.- In combination, a vacuum reservoir tank, and a section of rigid pipe rigidly secured upon said reservoirt-ank and having an offset portion spaced from the tank, said ofi'set portion being adapted for the reception of a mold flask.

5. In combination, a vacuum reservoir, a section of rigid pipe rigidly secured upon said reservoir tank and extending outwardly from the body of the tank to clear the body so as to leave a considerable clear space be-. low the end of the pipe, flask holding means at the end of the pipe, said pipe being adapted to pneumatically connect the interior of said tank with said flask holding means and the interior of a flask carried thereby, and I a manually operated valve in said pipe.

6. In combination, a vacuum tank, a flask 130 containing a mass of porous material having a mold cavity therein, the upper surface of the porous material in the flask being formed into a crucible in whichmetal may be melted, there being a direct permanently open restricted assageway between the bottom of said cruci 1e and said mold cavity, a pipe pneumatically connecting said mass of porous material with said tank and a valve in said passageway, the said "alve acting when closed to retain air in the space between the valve and the bottom of the crucible whereby the flow of metal through the said restricted passageway is prevented until the said valve is opened.

7. In combination, a vacuum reservoir tank, a section of rigid pipe rigidly secured upon said reservoir tank and extending outwardly thereform to clear the body of said tank so as to leave aconsiderable clear space below the end of the pipe, a mold flask carried upon the end of the pipe, and a crucible in direct communication with the mold also carried by the flask.

8. In dental inlay casting apparatus, the combination of a vacuum tank, a flask su porting shelf, a narrow outer sectionvof t e shelf being finished to be engaged with air tight fit by the finished end of a flask supported by the shelf, the inner section of the shelf being recessed to form a spacebelow the interior of a flask supported on the finished'outer section of the shelf, and means for connecting said space with said tank.

9. In dental inlay casting apparatus, the

a combination of a'vacuum tank, a flask supporting member, said member being finished to be engaged with air tight fit bya correspondingly finished flask supported by said member, said member being recessed to form a space below the interior of the supported flask, and means for connecting said space with said tank.

10. In a casting a paratus, the combination of a vacuum tan a flask in which metal is cast, and a flask supporting member, said flask and flask supporting member having parts finished to'form the male and female of a frusto-conical air tight fit, said flask supporting member having a cavity below the interior of the flask supported thereby, and means for connecting said cavity with said tank.

11. In a dental inlay casting apparatus, the combination of a vacuum tank, a flask supporting member, a section of said member being finished to a conical engaging surface to e engaged with air tight fit by a correspondingly finished sect-ion of a flask supported by said member, the member being recessed to form a space below the interior of a flask su ported on the finished section of said mem er, and means for connecting 7 wardly therefrom to clear the body 0 said J tank so as to leave a considerable clear space below the end of the standard, and mold flask holding means on the end of said standard, said flask holding means being pneumatically connected wlthsaid tank.

13. In combination, a vacuum tank, a flask containing a mass of porous material having a mold cavity therein, a crucible in which metal ismelted on top of said material, there being a direct permanently open restricted passageway between the bottom of said crucible and said cavity, a pipe pneumatically connecting said mass wlth said tank, a valve in said passageway, and a vacuum gage in open communication with said tank.

Signed by me at Chicago, Illinois, this 14th day of December, 1907. v

a F. LLOYD MARK. WVitnesses ALBERT J 01 m SAUsnR, SARAH LEWIS.

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