Metal founding – Process – Shaping a forming surface
Reexamination Certificate
2000-10-23
2002-10-22
Elve, M. Alexandra (Department: 1725)
Metal founding
Process
Shaping a forming surface
C164S045000, C164S137000, C249S057000
Reexamination Certificate
active
06467526
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of producing a jewelry ring or a portion of a jewelry ring. More particularly, the present invention relates to a method of molding a jewelry ring or a portion of a jewelry ring with a hollow portion and a beveled or rounded inner diameter on the shank of the ring.
BACKGROUND INFORMATION
In the art of jewelry making, various manufacturing processes are utilized to produce mass quantities of metallic jewelry articles in intricate detail: electroforming, die striking, and casting, for example. These processes facilitate high volume production at relatively low production cost. However, jewelry makers continue to seek innovative methods that reduce production costs even further while maintaining the ability to produce high quality articles with sufficient detail and comfort for the wearer.
Because jewelry making is an industry that relies heavily on precious metals, raw materials constitute a significant portion of the production costs. Methods that maximize the efficiency of materials usage in production are highly valued. It is well known in the art that producing jewelry articles of hollow or partially hollow construction may minimize such costs. In addition, processes that reduce the need to grind away material, such as seam lines that result from molding, minimize excess use of materials and time.
In addition to being mindful of the high production costs in jewelry making, jewelry ring makers recognize the importance of comfort in their designs. To achieve a more comfortable design, the prior art teaches methods by which jewelry rings can be manufactured with a shank that is beveled or rounded on the inside diameter of the shank i.e., that portion of the shank that contacts the finger. The shank of a ring is defined as the portion of the ring that encircles the finger. A beveled or rounded inside diameter provides improved comfort in the wearing, placement, and removal of the ring. In the art of jewelry ring making, prior to the present invention, there had been distinct lack of knowledge as to how to manufacture jewelry rings with a hollow portion and a beveled or rounded inside diameter on the shank in a vertical mold.
As shown in U.S. Pat. No. 3,838,728, “Method for Molding Finger Rings,” issued to Voegele on Oct. 1, 1974, and U.S. Pat. No. 3,511,466, “Mold for Wax Patterns for Casting Finger Rings,” issued on May 12, 1970 to Kaplan, conventional vertical molds used to mold ring replicas utilize upper and lower mold halves and a one-piece cylindrical plug to form a mold cavity in the shape of a ring. The upper and lower mold halves form the upper and lower halves of the circumference of the ring, respectively and hold the cylindrical plug in place to form a mold cavity. Once formed in the mold cavity, the ring replica and cylindrical plug are removed from the mold halves. The ring replica, having an inner diameter of the shank that is “flat,” is subsequently slidably removed from the cylindrical plug. Such vertical molds with the cylindrical plug are not capable of forming a ring with a beveled or rounded inner diameter on the shank.
One method of producing jewelry rings with an inner round radius design on the shank is disclosed in U.S. Pat. No. 6,032,719, “Method for Producing Hollow Jewelry Ring,” issued to Baum on Mar. 7, 2000; U.S. Pat. No. 5,916,271, “Hollow Jewelry Ring Having Inner Round Design,” issued to Baum on Jun. 29, 1999; U.S. Pat. No. 5,718,278, “Method for Producing Hollow Ring Having Inner Round Radius Design,” issued to Baum on Feb. 17, 1998; and U.S. Pat. No. 5,979,537, “Wax Replica and Soluble Core Insert Used for Producing Hollow Jewelry Ring,” issued to Baum on Nov. 9, 1999. These four patents disclose a horizontal two-part mold used to form a plastiwax replica of a ring. A horizontal two-part mold is oriented with the lower die and the upper die arranged to define a cavity having the circular shape of the ring; each die is formed with a cavity defining substantially one-half the ring shape in an axial direction. Investment casting is subsequently used to convert the plastiwax replica into a metal ring. A horizontally oriented mold configuration is utilized in this method because, according to the four Baum patents, “using the conventional techniques and the vertically oriented mold configuration, it is impossible to produce a ring having an inner round radius design.” See, e.g., U.S. Pat. No. 5,916,271 Col. 5, Lines 5-10.
The use of a horizontal mold has drawbacks. Due to the imperfect mating characteristics and shrinkage of the hardened material, a mold seam is inevitable in molds using two or more parts for defining an inner cavity. In utilizing a horizontal mold to achieve a beveled or rounded inside diameter on the shank, a seam will be produced along the entire inner and outer circumference of the ring. Removal of such a lengthy seam involves excess time and loss of excess material. Furthermore, horizontal molds cannot be used to produce rings with certain design features. In contrast, the present invention provides for a shorter seam line at only two places around the circumference of the ring.
It is known in the art to use a vertical mold with a multi-piece plug to form a ring of solid construction, i.e., no hollow portion, with a rounded or beveled inside diameter.
It is also known in the art to manufacture a hollow jewelry ring using a lost-wax casting process. The hollow wax replica ring used for the lost-wax casting is formed by molding plastiwax around a water soluble wax core insert in a vertical metal mold. The vertical mold is closed around a cylindrical core or mandrel. The wax core insert is generally arcuate in shape and has a respective spacer pin extending radially inwardly from each end of the arcuate core insert. The arcuate extent of the arcuate core insert is substantially 130°. A sprue terminating with an alignment peg extended radially inwardly from a central part of the arcuate core insert. The cylindrical mandrel is formed of two pieces which are locked together to form the mandrel while defining a receptacle to accommodate the alignment peg of the wax core. After the wax replica is formed around the core insert, the core insert is dissolved to yield a hollow space within the replica. The hollow wax replica is then used for a conventional lost-wax (investment) casting step. The prior art ring has an inner (finger-facing) surface that was cylindrical. That is, the prior art ring has a ‘flat’ inner radius design.
However, previously there has been no method of producing a ring with a hollow portion made using a soluble insert and a rounded or beveled inside diameter on the shank made using a multi-piece plug in a vertical mold.
SUMMARY OF THE INVENTION
The invention provides a method of producing a jewelry ring with a hollow portion comprising the steps of providing a vertical mold comprising an upper mold half and lower mold half; providing a multi-piece plug comprising at least a first piece and a second piece; providing a soluble insert; positioning said soluble insert and said multi-piece plug within said vertical mold so as to form a mold cavity; introducing molten material into said mold cavity; cooling said molten material to form a ring replica; separating the upper mold half and lower mold half; removing the multi-piece plug with said ring replica formed around it from within the upper mold half or lower mold half; separating said first piece of said multi-piece plug from said second piece and thereby releasing said ring replica from said multi-piece plug; dissolving the insert from said ring replica; casting a jewelry ring using said ring replica in an investment casting process.
The invention further provides a method of producing a ring replica comprising the steps of providing a vertical mold comprising an upper mold half and a lower mold half; providing a multi-piece plug comprising at least a first piece and a second piece; providing a soluble insert; positioning said soluble insert and said multi-piece plug within said vertical mold so as to
Elve M. Alexandra
Frost Brown Todd LLC
I.B. Goodman Manufacturing Co., Inc.
Kerns Kevin P.
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