1. Field of the Invention
The present invention relates to structure for inlaying precious metal in an outer peripheral surface of a ring and method for manufacturing a ring inlaid with precious metal in an outer peripheral surface.
2. Description of the Prior Art
As generally known in the art, conventional rings are classified into rings containing precious metals, such as gold or silver of soft materials, and rings having expensive jewels inlaid in an outer peripheral surface thereof.
Such conventional rings are made of soft materials, so that surfaces of the rings may be easily scratched. In addition, such conventional rings are so expensive that they cannot be extensively used as accessories.
In this regard, low-price rings capable of preventing surfaces thereof from being scratched have been developed.
Such low-price rings can be obtained through performing a series of processes of providing a powdered mixture containing at least 50 weight percent of tungsten carbide which is a rigid material used for a watchband or a bearing, compressing the powdered mixture through powder metallurgy, sintering the metallic material, and grinding/polishing the metallic material in the form of the ring.
Since the rings are made from the rigid material, the rings have rigid surfaces, so that the surfaces of the rings can be prevented from being scratched. In addition, since the rings are highly polished through the grinding/polishing process, the rings have superior luster characteristics, so that the rings are favorably commented in Western countries.
However, the conventional rings made of rigid materials, other than precious metals such as gold or silver, have not yet been extensively used in Oriental countries. This is because Oriental countries customarily prefer rings containing precious metals.
For instance, U.S. Pat. No. 6,928,734 discloses a ring, in which an annular groove is formed at an outer peripheral surface of the ring, which is made of a rigid material through powder metallurgy, and precious metal is inlaid in the annular groove.
However, in the ring disclosed in the above patent, a gap is formed between the annular groove provided in the outer peripheral surface of the ring through powder metallurgy and the precious metal (gold or silver) inlaid in the annular groove, so foreign materials may penetrate into the gap, thereby deteriorating an external appearance of the ring as well as enabling the soft precious metal inlaid in the annular groove to easily moving in the annular groove. In addition, the soft precious metal inlaid in the annular groove may be easily separated from the annular groove if a person takes off the precious metal by inserting a sharp tool, such as an awl, into the gap.