US2362136A - Casting - Google Patents

Description

Nov. 7, 1944. T. s. JUNGERSEN Y 2,362,136

CASTING Original Filed Jan. 11, 1940 s Sheets-Sheet 1 Nov. 7, 1944. 1-, e. JUNG-ERSEN 2,362,136 I CASTING Original Filed Jan. 11, 1940 3 Sheets-Sheet 2 gfmywm,

Nov. 7, 1944. T, G. JUNGERSEN 2,362,136

CASTING Original Filed Jan. 11, 1940 Q3 Sheets-Sheet 5 v 7%0ya9 Wi wam Patented Nov. 7, 1944 ThogerG. Jungersen, Summit, N. J.

Original application January 11, 1940, Serial No.

Divided and this application December 18, 1943, Serial N0. 514,838

(01. 22-200) The present invention relates to the art of 8 Claims.

making jewelry and other small metal articles of intricate design and fine detail, and among other objects, aims to provide an improved process or method of casting such articles.

A further object of the invention is to enable the. formation of intricate castings which will so closely resemble the original and finished product that the slow and tedious work of patterning and detail cutting required in connection with present casting methods is eliminated.

It is still a further object of the instant invention to provide a process of casting low temperature fusing metal and other materials directly into 'a plural part moldwhich may be of rubber to form objects of intricate design suitable for commercial or other use including relatively inexpensive jewelry.

Other objects and features of the invention will be evident, including the various steps of the improved process and attendant advantages over anything heretofore known, as set out in the foregoing description of a method and apparatus suitable for reproducing inexpensive low temperature fusing metals and other materials, articles, and jewelry especially of intricate design, such as articles containing hollows, undercut portions, and perforations, and of certain apparatus and material preferred for use in practicing the invention.

This application is a division of my copending application Serial No; 313,458, filed January 11,

Fig. 1 is an elevational view 'of a centrifugal casting machine;

Fig. 2 is an elevational view of the casting made in the mold parts illustrated in Figure 5.

Fig. 3 is a view in perspective of a model resting on a partially prepared rubber mold part; Fig. 4 is a longitudinal sectional view of the model resting on the partially prepared rubber mold part, and another mold part resting on said model, the assembly being arranged in a press;

Fig. 5 is a view similar to Figure 4 with the press in closed position;

Fig. 6 is a fragmentary sectional view of a mold part burned by a hot pointed instrument in order to facilitate removal of the setting portion of the ring mold; and

' Fig. 7 is a view in perspective of the completed mold taken from the press shownin Figs. 4 and 5.

A method of making a mold suitable for the casting therein of intricate designs, such as jewelry, including ladies rings, comprises the utilization of plastic mold parts, such as rubber mold parts, as will be described in connection with the drawings. The pattern 200 including a sprue former -20I is rested upon an unvulcanized rubber block 202, see Fig. 3. which may have a cutout portion or aligning deformation 203a about the margin of its upper face- 204 and inspaced relation tothe model 200. The said upper face is then coated with a suitabl parting material 205, such as an oil or talcum powder, or other powder that will not injure the rubber. A second block of unvulcanized rubber 203, see Fig.4, is then arranged over the model to sandwich the model between the blocks 202 and 203. The sandwiched assembly is then placed in a press and vulcanizing machine 206. After heat and pressure are applied to the blocks 202 and 203, see Fig. 5, they will take the form illustrated and effect a plural part mold such as illustrated in Fig. 7 after a gate 201 is cut into the now vulcanized block 203 in-communicating relation with the sprue former by the sprue former 20l. Due to the application of heat and pressure, the interlocking projection 203a will be formed to correspond to the aligning depression 203. The finished mold shown in Fig. 7 may then be utilized to cast objects of intricate design.

It may be desirable to cut the two rubber mold sections at various selected points, so that they may be easily removed from the casting formed therein. If the casting is quite plain in design, cutting may not be necessary as the flexibility of the mold section may be sufficient to permit their manual separation from the casting. If the casting is intricate such cutting becomes necessary. The location and direction of the cuts, and their number, will be indicated by the particular design, the object being to insure separation of the rubber mold from the casting, which may be of low temperature fusing metal, without any distortion or other injury whatever to the latter. and without detrimentally affecting the accuracy or details of the mold. As an example, there is shown in Fig. 6, a rubber mold portion 22, with a deeply undercut or hollowed model P, the actual volume of which may be reduced by the insertion of a heated pointed instrument I to form a cavity 8 therewithin. Moreover, a plurality of slits 9 are cut into the opposite sides to extend part way across the mold body, so that the respective portions will be free to flex easily in being withdrawn through the opening I0 of the model P.

The two registering rubber mold sections thus formed about the model are depicted in Fig.7 of the drawings. According to the preferred embodiment of the invention, these two sections are produce a casting of intricate design.

Prior to the casting of the low temperature I fusing metal or other material the registering surface of the two mold sections may be covered with a fluid or other suitable substance or lubricant for facilitating their separation. Such a substance is preferably an oil, which will not injure the mold, such as for example, castor oil. If the casting is to beformcd from a readily fusible metal, such as "Woods metal, the separating material may assume the form of a dry powder, The mold sections are brought together and sufiiciently tightly clamped to prevent their distortion, yet flrmly enough to assure a faithful reproduction of the original model and the flexible mold is now ready for the casting therein of the low temperature fusing metal or other material.

The flexible mold is now preferably put in a centrifugal casting machine. These machines are already available machines of commerce, and an illustration of such a typical machine M is found in Fig. 1, diagrammatically showing a mold in position therein. Instead of employing such a machine, the article to be formed may be cast by centrifugal force exerted manually, as by whir1 ing the mold on the end of a string or cord. It is to be understood that other force suflicient to effect the entrance of the material within the intricacies of the mold may be utilized without departing from the spirit of the invention.

It is preferred to employ centrifugal force when casting readily fusible metal or other material in a rubber mold, for the reason that centrifugal force acts in a peculiar way to cause the molten material to completely fill the mold space and yet permit escape of all the air through the center of the mold cavity while the molten material is still liquid with the result that the casting is a perfect reproduction of the cavity in the mold. Thus any air which may be trapped in a recess of the mold will be crowded back into the fluid body under the pressure applied thereto and the fluid material will progress into the recess of the mold as it crowds the air therefrom and will progressively congeal against the wall of the recess until the extreme limits are reached so that the finest of cavities will be completely filled. Either centrifugal force or an applied pressure is very essential in the production of perfect castings in read ily fusible material, especially where the castings are of small dimensions and/or of intricate design.

The resultant casting C, whether of readily fusible metal or other material requires nothing but extremely simple finishing operations to be ready for the market. The only part of the casting requiring any rough finishing work at all is the part H, see Fig. 2, where the sprue joins the casting, which may be smoothed by filing, grinding, cutting or otherwise. The final bufling and polishing operation may thus be performed directly on the article as removed from the mold. Thus the process effects very large savings especially in the manufacture of jewelry of intricate I design.

With known processes of casting small articles of intricate design such as the cuttlefish process, for example, it may take an expert workman several hours to finish the article to a commercial standard, while with the present process only a few minutes are required to finish the article to the same standard.

It is to be understood that it is within the scope of the invention to utilize the casting C as a model to make further castings, if desired.

It is contemplated that synthetic rubber such as polymerized chloro 2 butadiene 1,3 be utilized in place of natural rubber as the mold material.

It will be obvious to those skilled in the art that various changes may be made in this device without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

I claim:

1. In a process for casting pieces of Jewelry or other articles of intricate design from the low temperature fusing metals, the steps comprising making a plural part mold by arranging one or more models of the articles to be cast between a plurality of slabs of flexible mold forming material, making registry formations between contacting surfaces of said slabs, applying a separating medium to the contacting surfaces of said slabs, setting the slabs within a confined space under the influence of heat and pressure to make a relatively rigid but permanently flexible mold capable of withstanding successive casting therewithin of articles of the low temperature fusing metals by centrifugal force, successively casting articles of low temperature fusing metals within saidmold by centrifugal force.

2. The process recited in claim 1, said mold forming material which under the influence of heat and pressure forms a permanently flexible mold being rubber.

3. The process recited in claim 1, the articles .corresponding to said mold being cast in that metal group consisting of tin and tin alloys.

4. The process recited in claim 1, said articles corresponding to said mold being cast in that metal group consisting of lead and lead alloys.

5. A process of casting articles intricate to the extent of having one or more small projections or depressions comprising: making a plural part mold by arranging one or more models of the articles to be cast between a plurality of slabs of flexible mold forming material, making registering formations between contacting surfaces of said slabs, applying a separating medium to contacting surfaces of said slabs, molding the slabs about the model or models under the influence of heat and pressure to form a relatively rigid though permanently flexible mold capable of withstanding successively casting therewithin articles by an applied force suflicient to fill the mold cavity in all its intricate details, successively casting articles within said mold within an applied force sufficient to fill the mold cavity in all of its intricate detail.

6. The process recited in claim 5, said mold forming material which under the influence of heat and pressure forms a permanently flexible mold being rubber.

'l. The process recited in claim 5, the articles corresponding to said mold being cast in. that metal group consisting of tin and tin alloys.

8. The process recited in claim 5, said articles corresponding to said mold being cast in that metal group consisting of lead and lead alloys.

THOGER G. JUNGERSEN.

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