US1218991A - Compound apparatus for casting metals in vacuum. - Google Patents

Description

E. FERRARI.

COMPOUND APPARATUS FOR CASTING METALS IN VACUUM.

APPLIcATIoN FILED APII.18. 1913.

1,218,991. Patented Mar. 13,1917.

E FEKRARI.

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PATENT OFFICE.

ERMINIO FERRARI, OF VENICE, ITALY.

COMPOUND APPARATUS FOR CASTING METALS IN VACUUM.

Specification of Letters Patent. Patented )Ian 13, 1917.

v Application led April 18, 1913. Serial No. 761,999.

To all whom z't may conc-em.'

Be it known that I. ERMINIO FERRARI, a subject of the King of Italy, residing at No. 3816 Campo S. Angelo, Venice. Italy, have invented certain new and useful Improvements in Compound Apparatus for Casting Metals in Vacuum, of which the following is a specification.

The invention relates to an apparatus for casting metals in a vacuum and more particularly relates to that class of apparatus wherein vacuum generating means are embodied with a flask device.

According to the present improvements means are provided to eect the suction with a relatively small force. which means permit of any dimension being given to the vacuum cylinder as well as to arrest the stroke at any point of its length.

A further object of the invention is to provide means for maintaining an etiicient vacuum. independently of the dilation of the parts of the flask device. Y

A suitable construction of compound apparatus for casting metals by the lost wax process by means of a vacuum. according to the present invention which is specially adapted for casting articles for dental purposes (such as dental plates) sculptured articles and jewelry, etc., is illustrated by way of example in the accompanying drawings,

in which Figure 1 is a diagrammatic central section of a complete apparatus:

Fig. 2 is a separate view of the upper part of the apparatus illustrating the connection of the device containing the clay or plaster mold with the upper part of the machine for producing a vacuum;

Fig. 3 isk a section on the line wof Fig. 1.

As shown, 1 is the vacuum chamber in which a vacuum is produced by means of a piston 2, working hermetically and mounted on the end of a screw threaded shaft 3 in the lower part of the screw thread of which there is provided a groove 4 (Fig. 3) so arranged that by means of a stop pin 5 entering said slot the piston shaft which is driven by means of a screw hand wheel 6 shall be able to move only in the direction of its length instead of revolving on its own axis as would be the case in the absence of the stop pin 5.

The vacuum chamber 1,-is connected to any suitable device 7 for indicating the degree of vacuum produced. From the chamber 1, a pipe 8 communicates with the casting apparatusV 9 for the purpose of producing a vacuum in the latter.

In the passage 8 there is fitted a cock 8 capable of closing air tight for the purpose of preventing the formation of a vacuum in the apparatus 9 before the desired moment. Y f' The apparatus 9, (Figs. l and 2) consists of a conical cylinder 10 which is connected by means of a union nut 11 to a support 12 through which the tubular passage 8 passes centrally.

. The cylinder 10 is closed at its lower end by a plate 13 provided on its'underside with a circular flange 14 arranged to engage in a circular recess 15 formed in the enlarged upper part of the support 12, in which recess, there is arranged a strong coiled spring 16. This spring has the function of pushing the plate 13 upward and thus closing the conical part l0 air tight containing the mold 20. The mold 20 is provided at its upper part which alone is exposed, with a central cav-ity in which is placed the metal 19 which on melt-ing is intended to take the place of the wax that has composed the pattern 17.

Instead of a single circular recess Jfor the spring 15, a second recess concentric to the first mentioned recess may be provided for use in those cases where it is required to employ a smaller plate 13. I 1 The operation of the apparatus is as foloWs:-

A vacuum is formed in the chamber 1 by means of the piston 2, and at the same time the wax pattern 17 situated in the center of the mold is melted by heating the mold 2O to incandescence. After cooling, the mold is placed in the conical casing 10 and the whole is mounted on the top of the support 12, and the parts are connected firmly together by tightening up the union nut 11.

When this is done, the metal 19 is melted by means of a blow pipe. Then the cock 8 is opened so that the vacuum acting upon the apparatus 9 will cause, by reason of the great atmospheric pressure acting from the outside. the molten metal to pass downwardly by means of small passages left in the material of the mold 20 until it fills the cavity left by the melting of the wax. The casting thus made is not removed until it has become quite cool.

Having now described my invention what I claim as new and desire to secure by Letters Patent iszl. A flask device for vacuum casting apparatus comprising a lconical flask, a movable bottom to the flask, a support for the flask and movable bottom, vacuum generating means, a duct in said support for connecting the flask to the vacuum generating means, a circular groove on the support, a spring in the groove acting against the bottom and means for mounting said flask on the support and for setting the spring in tension against the bottom.

Q. A flask device foi` vacuum casting apparatus comprising a conical flask having a flanged base, a movable bott-om to the flask, a

tubular projection romthe bottoln, a support for the flanged ask and movable bottom, the support having a duct to the vacuum generating means, a circular groove on said support to receive the tubular projection, a spring in the groove, a screw thread around said support, a union nut for securing the flask on the support and to draw the movable bottom against the said spring.

In testimony whereof I affix my signature in presence of two Witnesses.

G. GIACOMO GUARNIER, P. J. KELLAR.

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