US 3561521 A
Description (OCR text may contain errors)
0 United States Patent 1 3,56 1,52 1
 lnvemor George e 3,041,689 7/1962 Peras 164/35 Hiahah, 3,396,934 8/1968 Ferris 164/35 [21 Appl. No. 803,009 3,402,754 9/1968 Christian 164/35 22 Filed 27 9 9 3,402,755 9/1968 Christian 164/35 45 p d F b 9, 1971 3,418,407 12/1968 Eilers 264/221X [7 ign Micro'Thermal Applications, Inc. Re26,785 2/1970 Kaplan 164/34 Hialeah F" Primary Examiner-Robert F. White a corporanon of Delaware Assistant Examiner-Allen M. Sokal Att0rney-Ryder, McAulay & Hefter  METHOD FOR CHANGING THE SIZE OF WAX RING PATTERNS 4 Claims, 7 Drawing Figs.  U.S.Cl 164/45, ABSTRACT; A method f accurateuy changing the inside 1 4/ 2 /1 2640261264259 diameter of wax patterns for finger rings. A portion of the t of the wax attern on each ide of the p ue iece i  Field of Search 264/226, removed and a bar f the desired Size is inserted in the ring 225,221,259,219, 152, 138; 164/45, 17, 34,3 The ring and bar are affixed to mold and wax is injected through a bore hole in the mold and into the open portion of  Reerences Cited the band of the ring for completing the same. The mold has UNITED STATES PATENTS means for gripping the bar and comprises a cavity with a 2,790,220 4/1957 Fox 164/35 design therein.
METHOD FOR CHANGING THE SIZE OF WAX RING PATTERNS BACKGROUND The lost wax process involves making a wax pattern for every casting to be produced. These patterns are made by the injection molding of wax into precision metal dies. The wax patterns, with sprues attached, are affixed to a plate or base and the assembly is placed in a metal flask which is then filled with a refractory investment mixture. After the investment material has hardened, it is inverted in an oven at an elevated temperature and the wax pattern is melted out of the investment. Molten metal is then poured into the investment to form the final product such as a ring. After the metal solidifies, the investment is broken away and the casting is removed and finished by polishing.
The metal dies used in the above process are difficult and costly to make. In making rings, one or two dies of a standard size are used for all wax patterns. The wax patterns are therefore made in standard sizes, such as size for men and size 7 for women. In order to make a different size ring, a wax pattern is first made in the standard size. The sprue portion of the ring is then cut out and the ring is placed on a a tapered mandrel which is scored with the various ring size markings. A hot iron is dipped into a reservoir of wax and the ring opening is then welded to close the band of the ring.
The disadvantages of this method are threefold. The welding obliterates any decorative detail in the area of the weld. In addition, the welded portion is tapered in accordance with the shape of the tapered mandrel. After the weld is completed, the sprue must be replaced carefully onto the ring for proper formation of the investment.
The present method overcomes the above objections and disadvantages in the prior art by the provision of a method described and shown in the following specification and drawings.
THE INVENTION A wax pattern is formed by any conventional technique. In the improved method and means of this invention, the wax pattern is cut on each side of the sprue and a bar, such as a cylindrical bar. having the desired diameter is then placed within the ring. The portions of the band adjacent the cut portion are then positioned against a half mold which has the desired detail for the band portion of the ring. The mold also has a bore hole or gateway which is then placed against a wax injector. The wax is injected into the half mold and seals the band of the ring. At the same time, the desired detail on the band of the ring and an appropriately positioned sprue are formed on the ring. The half mold includes means for gripping the cylindrical metal member and pressing it against the half mold.
The invention is set forth in greater detail in conjunction with the attached drawings in which:
FIG. 1 is a perspective view of a standard size wax pattern for a finger ring.
FIG. 2 is a perspective view of the pattern shown in FIG. 1 with the sprue and a portion of the band cut away.
FIG. 3 is a front elevation of the ring shown in FIG. 2 illustrating the reduction of the internal diameter.
FIG. 4 is a top view of the half mold for remaking the band portion of the wax pattern.
FIG. 5 is a sectional view of the mold of FIG. 4 through 5-5, with a ring positioned thereon.
FIG. 6 is a sectional view of the mold of FIG. 4 through 6-6 and of a ring thereon.
FIG. 7 is a perspective view of the pattern shown in FIG. I having a reduced inside diameter.
- Referring to FIG. I, a wax ring pattern 11 of a standard size is shown with an inside diameter D. An integral cylindrical sprue 12 extends normal to the lower or narrow side of the band and is normally used for the handling thereof and to form a gateway for the latter pouring of metal into an investment.
Dual ridges I3 are shown which are representative of the designs which may appear on the band portion of the ring.
FIG. 2 shows the first step in the preparation of a ring of a changed size. The sprue l2 and an adjacent portion I4 of the band of the pattern have been removed. This is accomplished by merely cutting through the band portion of the ring with a knife or other sharp or heated instrument.
FIG. 3 illustrates the reduced inside diameter d of the pattern ll desired. Alternatively, the inside diameter d may be slightly larger than the original diameter D. The new inside diameter of the ring is determined bythe diameter of member IS. The term cylindrical as used for member is is intended to encompass the oblong shape which is used for many rings wherein the diameter d, as shown in FIG. 3. is not as great as the diameter in a direction perpendicular thereto.
FIG. 4 is a top view of a half mold 16 for use in the present invention. A gateway l7 communicates with one side of the half mold and mold cavity 18. The mold cavity includes grooves I9 representative of a design which is desired for the band portion of the ring. The cavity 18 is. shaped to form a segment of the band portion. The half moldl includes holes 20 for the purpose set forth in greater detail below.
A cross section of the half mold I6 through lines 5-5 is shown in FIG. 5. A ring lll having a cylinder 15 therein, corresponding to the arrangement shown in FIG. 3, is secured to the half mold by means of a bar 21 through the center of the cylinder. The bar 21 is attached to the half mold by securing means 22 in holes 20. This arrangement is formed by positioning a cylinder 15 within the ring Ill and compressing the ring tightly around the cylinder. The ring is then placed into the cavity 18 of the half mold 16 while maintaining a compressive force on the ring. Simultaneously, the securing means 22 are tightened to maintain a tight fit between the half mold, the ring, and the cylinder. One of means 22 may be shorter than the other to assist in holding the wax pattern securely against the half mold and in the cavity.
A cross-sectional view through lines 6-6 of FIG. 4 is shown in FIG. 6 to illustrate the manner in which the opening in the band of the ring is aligned with the gateway 17 in the half mold 16.
The change in ring size is completed by placing the enlarged portion 23 of the gateway I7 against the nozzle of a molten wax injector. The injector is of conventional construction and is not shown herein. It comprises a reservoir of wax which is maintained in a molten condition. Upon pressing the gateway opening 23 against the injector nozzle, an air cylinder is actuated to force the liquid wax into the half mold. The flowing wax closes the opening in the band and reforms the sprue and desired design characteristics.
The completed wax pattern is shown in FIG. 7. The above process and device provides a new band portion 24 within dotted lines 25. The design 26 corresponds with the grooved portions of the half mold l9 and the sprue 27 is properly positioned on the band. Note that the sprue 27 and reformed por' tion 24 would normally be, opposite the stone portion 28 of the ring. The removal and reforming of this. portion preserves the symmetry of the ring and is usually at the narrowest portion of the ring.
This invention has been described in terms of specific embodiments set forth in detail. Alternative embodiments will be apparent to those skilled in the art in view of this disclosure, and accordingly such modifications are to be contemplated within the spirit of the invention as disclosed and claimed herein.
I. The method of changing the size of a wax pattern for a ring having a first predetermined diameter which comprises removing a portion of the band of said ring, inserting a bar having a second predetermined diameter into the band of said ring, compressing said ring around said bar to maintain contact between said band and said bar, positioning said band including the space leftby said removed portion in a mold having a cavity which corresponds to the desired shape of said 3. The process of claim 1 wherein said cavity has a shape which produces a desired design on said band upon injecting of said wax.
4. The process of claim 2 wherein said positioning of said band and said bar into said mold comprises attaching said bar to said mold.