US946677A - Means for casting dental fillings. - Google Patents

Description

APPLIUATIOH FILED OCT. 7, 1907.

Patented Jan. 18,1910.

UNITED STATES; ra'rnntr OFFICE. 4

JOHN P. ,LEDERLE AND FRANCIS A. LEDERLEQOE CHICAGO, ILLINOIS means ron oasrme DENTAL Funn es.

' To all whom. it may concern:

Cll

. clea r, and exact description.

Our invention relates to certain, new and useful improvements in molds used by dentists for casting the fillings of teeth.

Heretofore in the prosecution of the art of casting dental fillings the means employed were designed with a view to the casting of but one filling at a time, and were so constructed that this casting had-t0 be made in the center of the mold and did not allow for irregularities in the shape of the castingswhich would make it more convenient to place the sprue nearer one side of the flask than the other.

An object of our invention is to enable two or more castings to be made in a mold of V the size which heretofore was devoted to the making of one casting.

Another object is to enable a casting to be made nearer one side of the flask than the other, and to locate the sprue at whatsoever point the irregular shape of the casting to he made would make it most convenient. A further object of our invention is to provide an improved sprue former which can be conveniently inserted into the pattern of the cavity of the tooth of the patient when it is desired to remove the same, and is weighted so as'to hold the said pattern up out of contact from the surface 11 on which the sprue former rests when it is aid down, and will form a countersink or'crucible for the metal around the mouth of the sprue regardless of whether it is located in the center of the mold or not, substantially as hereinafter fully described and as particularly pointed out in the claims.

In the drawingsz-Figure 1 is a transverse vertical section of a flask showing our improved sprue former in connection with the same. Fig. 2 is a similar view with the sprue former removed. Fig. 3 is a plan view of the same. Fig. 4 isa plan view of the invention.

In the drawings, A represents a flask Specification of Letters latent.

Patented Jan. 18, 1910.

' Application filed 0mm 7; 1907. Serial No. 396,295.

. which :is; preferably. cylindrical in shape and 15 represents asprue-former consisting of a wire or rod, sa-y an inch in length having its upper end bent into acircle or other snitably shaped loop I), and having mediate said loop and its lower end. a metal boss 0, preferably, of a diameter slightly less than mehalf that of the inner circiunferelicc of the flask. The weight of the looped end of the sprue-former is so much greater than its opposite end that when said sprue-former is laid down. the boss serves as a fulcrum and the straight end of the former which is adapted to be stuck into the plastic pattern will always be raised from the surface u on which said former rests. This boss is 0 an inverted,coneshape'with the conical sides thereof farthest from the loop, although it may be made almost hemispherical, substautially as shown by the boss (I of the sprue D shown in Fig. 5 of the drawings. TheIloop b affords the operator a suitable finger grasp with which to grasp the sprue when it is desired to insert the same into thepattern or 1 plastic material formedi-n the cavity of the tooth of the patient when it is desired to withdraw the same; and provides the means for suspending the plastic pattern on its lower end within the flask at any suitable .5

point. The plaster of paris or other suitable molding material, while in a very soft condition, is poured into the flask until the latter is filled to about the level of its upper edge. The pattern is then inserted into the soft moldin material by means of the sprueformer unti the boss thereof is embedded up to its upper side, thus completely enveloping the pattern. When the molding material'is-se't the sprue-former is pulled upward with sufiicient force to extract the lower end of the same from the pattern, and withdraw it from the flask. \Vhen thus withdrawn the sprue-former leaves a sprue a: and a countersink or crucible e in the upper surface of the mold. The mold is then heated to solidify the-molding material and melt the material of the pattern until it, the latter, volatilizes, or until it is so lique- 2 j i j 946,677-

by any suitable means, in any position desired within themold so that the sprueholder can be made to lead from the highest part of an irregular pattern, no matter where said highest point may be located, and thus avoid any overhang in the molding chamber and avoid forming an air space in the same above the end of the sprue-h'ole.

\Ye do not desire to be confined to the exact' length of the sprueformer as shown, nor to the shape of the boss of the same, for it is obvious that they may be changed, and the loop omitted without departing from the spirit of our invention.

\Vhat we claim as new is 1'; A device of the character described comprising a crucibleformer having tapered sides, and a fixed rod extending therethrough that is so constructed that the portion therei of opposite the tapered sides overbalanees the latter. 1

2. A device of the character described comprising a crucible former having tapered sides, and a gate pattern consisting of a rod the upper end of which projects above the top of said crucible former and is provided with a finger-grasp that overbalancesthe opposite end of said device.

EEQA device of the character described comprising a crucible former having tapered sides, and a gate pattern consisting of a rod extending through and projecting beyond said former the end thereof above the top of said former shaped into a loop that overbalances the opposite endofsaid rod.-

v In testimony whereot we have hereunto set our hands and seals this 4th day of October, A. D. 1907. Q

JOHN P. LEDERLE. IjL. 8.] FRANCIS A. LEDERLE.

lVitnesses FRANK D. THOMASON, E. K. Lonny.

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