Patents by Inventor Dwarika P. Agarwal
Dwarika P. Agarwal has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8419867Abstract: Rose-color and yellow-color gold alloys are formed from a gold-base alloy containing silver and copper. Mining these elements is usually highly detrimental to the environmental. Environmentally friendly alloys are obtained through the use of recycled elements and elements recovered from mines utilizing specific guidelines. Jewelry manufactured from these environmentally friendly alloys may be more receptive to a consumer, resulting in a competitive advantage.Type: GrantFiled: August 15, 2008Date of Patent: April 16, 2013Assignee: Hallmark Sweet, Inc.Inventors: Dwarika P. Agarwal, Grigory Raykhtsaum, Richard V. Carrano
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Publication number: 20090191089Abstract: Rose-color and yellow-color gold alloys are formed from a gold-base alloy containing silver and copper. Mining these elements is usually highly detrimental to the environmental. Environmentally friendly alloys are obtained through the use of recycled elements and elements recovered from mines utilizing specific guidelines. Jewelry manufactured from these environmentally friendly alloys may be more receptive to a consumer, resulting in a competitive advantage.Type: ApplicationFiled: August 15, 2008Publication date: July 30, 2009Inventors: Dwarika P. Agarwal, Grigory Raykhtsaum, Richard V. Carrano
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Patent number: 7413705Abstract: Improved 14-karat rose-colored gold alloy compositions include: about 58.5% gold; about 9.0-12.0% silver; about 0.0-0.2% zinc; about 0.3-0.4% cobalt; about 0.0-0.02% iridium; and about 29.0-33.0% copper. Improved 18-karat rose-colored gold alloy compositions include: about 75.2% gold; about 7.0% silver; about 0.0-0.2% zinc; about 0.3-0.4% cobalt; about 0.0-0.02% iridium; and about 17.0-17.5% copper. The hardness of these compositions are capable of being selectively changed between their respective annealed-hardness and age-hardness values. The color of these compositions is between about 5-7 CieLab a* color units and between about 17-21 CieLab b* color units.Type: GrantFiled: May 9, 2005Date of Patent: August 19, 2008Assignee: Leach & Garner CompanyInventors: Dwarika P. Agarwal, Grigory Raykhtsaum
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Patent number: 7198683Abstract: A sterling silver alloy composition of exceptional and reversible hardness and enhanced tarnish resistance, consists essentially of the following parts by weight: at least about 92.5% silver; about 4.4% to about 5.25% copper; about 0% to about 1.0% zinc; about 0.85% tin; about 0.05% to about 0.3% lithium; about 0.05% to about 0.5% silicon; about 0% to about 1.2% germanium; and about 0% to about 0.02% boron.Type: GrantFiled: August 26, 2004Date of Patent: April 3, 2007Assignee: Leach & Garner CompanyInventors: Dwarika P. Agarwal, Grigory Raykhtsaum
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Patent number: 7135078Abstract: A nickel-free white gold alloy composition having selectively reversible hardness characteristics between its annealed- and aged-hardness values, consists essentially of: about 55–60% gold; about 6.0–10.0% palladium; about 5.0–12.0% copper; about 0.1–2.0% zinc; and about 20–30% silver. A 14-karat nickel-free white gold alloy composition, consists essentially of: about 58.5% gold; about 25.0–27.15% silver; about 6.0% palladium; about 5.0–12.0% copper; about 0–2.0% zinc; about 0–0.2% cobalt; about 0–0.005% iridium; and about 0–0.01% lithium.Type: GrantFiled: December 5, 2005Date of Patent: November 14, 2006Assignee: Leach & Garner CompanyInventors: Dwarika P. Agarwal, Grigory Raykhtsaum
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Patent number: 6676776Abstract: A 14-karat gold alloy composition having a desirable yellow color and with reversible hardness contains about 58.65 weight percent gold, about 11.5-25.0 weight percent silver, about 11.85-23.35 weight percent copper, and about 2-7 weight percent zinc. The color of the composition has a value of between about −3.0 to about 0.5 CieLab a* color units, and has a value of between about +20.0 to about 22.0 CieLab b* color units. The alloy has a hardness ratio between about 0.4-2.0, and color ratio of less than about 1.0.Type: GrantFiled: August 20, 2002Date of Patent: January 13, 2004Assignee: Leach & Garner CompanyInventors: Dwarika P. Agarwal, Grigory Raykhtsaum
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Patent number: 6406568Abstract: An improved 18-karat green gold alloy composition comprises about 75.0% gold; about 6.0-7.0% silver; about 9.0-11.7% copper; and about 6.5-9.0% zinc. The improved alloys are capable of being age-hardened to a hardness of about 240 VHN by being heated to about 550° F. for about one hour, and thereafter being permitted to cool in air. The hard-nesses of the alloys are reversible between their aged-hardness and annealed-hardness values. The color of said composition is between about −1.5 to about −3.0 CieLab a* color units, and between about 19 to about 26 CieLab b* color units.Type: GrantFiled: August 22, 2001Date of Patent: June 18, 2002Assignee: Leach & Garner CompanyInventors: Dwarika P. Agarwal, Grigory Raykhtsaum
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Patent number: 5919320Abstract: A hardenable white gold alloy consists essentially of about 55-60 % gold, about 12-20% silver, about 8-15% copper, about 8-18% palladium, about 0.0-1.0% tin, zinc indium or cobalt, and, optionally, about 0.005-0.02% iridium and/or ruthenium, and also about 0.01-0.03 weight percent lithium. The alloy is nickel-free, but has a pleasing white color similar to that of nickel-containing white gold alloys. The alloy has a fine grain structure, a lower hardness in its annealed condition, but is capable of being hardened to an exceptional hardness value. The hardening procedure is reversible.Type: GrantFiled: November 17, 1997Date of Patent: July 6, 1999Assignee: Leach & Garner CompanyInventors: Dwarika P. Agarwal, Grigory Raykhtsaum
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Patent number: 5598722Abstract: An improved bangle closing mechanism (26) is adapted to releasably join two tubular arcuate bangle halves (11, 12). The improved closing mechanism has a keeper bar (28) provided with a proximal portion (29) adapted to be operatively engaged with the first bangle half (11), an intermediate portion (30) extending between the bangle halves and penetrating a narrowed opening (23) in the second bangle half (12), and an enlarged ball-like head portion (31) operatively arranged within the second bangle half. The projected diameter (d.sub.1) of the head portion is greater than the projected diameter (d.sub.2) of the narrowed opening. The head portion prevents the keeper bar from being withdrawn from the second bangle half, and facilitates sliding movement within the second bangle half as to the bangle halves are moved relatively toward or away from one another.Type: GrantFiled: April 3, 1995Date of Patent: February 4, 1997Assignee: Leach & Garner CompanyInventors: Edwin F. Leach, II, Marinko Markic, Ronald E. Precourt, Jr., Michael A. Gayton, Dwarika P. Agarwal
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Patent number: 5180551Abstract: A unique hardenable gold based alloy, especially a 14 karat gold alloy containing gold, silver, copper, zinc, cobalt and an alternative alloy additionally containing iridium. The alloy has a fine grained structure, a lower hardness in the soft condition, a nice yellow color and a capability to be hardened to an exceptional hardness value. The alloy contains approximately 58.3% gold (Au), between about 10% to about 14% silver (Ag), between about 2.5% to about 3.0% zinc (Zn), between about 0.2% to about 1.0% cobalt (Co) and the balance of the alloy being copper (Cu) with the special provision that the ratio of the weight percent amounts of copper to, the sum of the silver and two (2) times the zinc amount, [Cu/(Ag+2Zn)], has a value of between about 1.3 to about 2.5. The copper to silver weight percent ratio [Cu/Ag] of between about 2.0 to about 3.8, in combination with the ratio of copper to, silver+2.times.Type: GrantFiled: October 30, 1991Date of Patent: January 19, 1993Assignee: Leach & Garner Co.Inventor: Dwarika P. Agarwal
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Patent number: 5139883Abstract: Gold, copper, silver, palladium or aluminum and their alloys, but preferably gold or gold alloy, which may be in the form of a wire, has deposited thereon or contained within the wire, a material such as metals or metal alloys which diffuse into the gold or into the other listed metals. With the passage of time and exposure to temperature the deposited metal or metal alloy continues to diffuse into the gold forming intermetallics with the gold and thereby causing the resistivity of the gold to increase and causing the gold to become progressively more brittle until such time as the gold wire ruptures at a stress point. At a given temperature, the elapsed time until rupture takes place depends upon the metal or metal alloys deposited on or contained within the gold. Lead, indium, gallium, tin, bismuth and aluminum and the alloys of these metals diffuse into and form intermetallics with the gold.Type: GrantFiled: May 9, 1989Date of Patent: August 18, 1992Inventors: Grigory Raykhtsaum, Dwarika P. Agarwal, James R. Valentine, David J. Kinneberg
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Patent number: 5130689Abstract: Gold, copper, silver, palladium or aluminum and their alloys, but preferably gold or gold alloy, which may be in the form a wire, has deposited thereon or contained within the wire, a material such as metals or metal alloys which diffuse into the gold or into the other listed metals. With the passage of time and exposure to temperature the deposited metal or metal alloy continues to diffuse into the gold forming intermetallics with the gold and thereby causing the resistivity of the gold to increase and causing the gold to become progressively more brittle until such time as the gold wire ruptures at a stress point. At a given temperature the elapsed time until rupture takes place depends upon the metal or metal alloys deposited on or contained within the gold. Lead, indium, gallium, tin, bismuth and aluminum and the alloys of these metals diffuse into and form intermetallics with the gold.Type: GrantFiled: January 16, 1991Date of Patent: July 14, 1992Assignee: Leach & Garner Co.Inventors: Grigory Raykhtsaum, Dwarika P. Agarwal
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Patent number: 5000779Abstract: The subject of this invention is the development of new alloys along with new processing approaches for the utilization of the alloys. A particular class of alloys comprises at least one noble metal selected from the group comprising gold, palladium, silver and copper and an amount of between about 0.20 weight percent and about 0.80 weight percent of at least one metalloid selected from the group of metalloids consisting of boron, phosphorous, silicon and lithium. Rapid solidification technology in powder fabrication and the addition of metalloids have been combined to produce a new class of palladium based alloys. The metalloid additions greatly increase the hardness, enhance the fine grain structure and aid sintering densification. Net-shape forming is a benefit derived from the characteristics of the new alloys.Type: GrantFiled: May 18, 1988Date of Patent: March 19, 1991Assignee: Leach & GarnerInventors: Randall M. German, Laura L. Bourguignon, Dwarika P. Agarwal, Shaji Faroog
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Patent number: 4869757Abstract: A unique hardenable silver alloy is provided which is solution annealed and preferably age-hardened to yield a silver alloy of exceptional and reversible hardness. The alloys utilize intermetallic systems comprising; silver, copper, combined with lithium alone or tin alone in varying percent amounts, or silver, copper, lithium and either tin or antimony, or silver, copper, lithium, tin and antimony, or silver, copper, lithium, tin and bismuth, or silver, copper, lithium, tin, bismuth and antimony.Type: GrantFiled: April 13, 1987Date of Patent: September 26, 1989Assignee: Leach & Garner CompanyInventors: Thomas W. Eagar, Dwarika P. Agarwal, Laura L. Bourguignon, Rosaire Marcotte
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Patent number: 4810308Abstract: A unique hardenable silver alloy is provided which is solution annealed and preferably age-hardened to yield a silver alloy of exceptional and reversible hardness. The alloys utilize intermetallic systems comprising silver, copper, combined with lithium alone or tin alone in varying percent amounts, or silver, copper, lithium and either tin or antimony, or silver, copper, lithium and either aluminum or indium or zinc, or silver, copper, antiomony and either aluminum or indium or zinc, or silver, copper, lithium, tin and antimony, or silver, copper, lithium, tin and bismuth, or silver, copper, lithium, tin, bismuth and antimony.Type: GrantFiled: January 19, 1988Date of Patent: March 7, 1989Assignee: Leach & Garner CompanyInventors: Thomas W. Eagar, Dwarika P. Agarwal, Laura L. Bourguignon, Rosaire Marcotte
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Patent number: 4399096Abstract: A brazing alloy composition for joining chromium containing base metal alloys containing, by weight, palladium about 39%-60%, nickel about 20%-47.5%, and at least one element selected from the group consisting of silver 0-35%, tin 0-32%, indium 0-32% and gallium 0-11%; and optionally containing one or more elements selected from the group consisting of gold 0-10%, germanium 0-4.4%, silicon 0-2.9% and about 0.025% of a known deoxidizer such as lithium. The alloy exhibits good wetting and flowing characteristics and has excellent strength and corrosion resistance at elevated temperatures. The brazing alloy is particularly useful for joining chromium containing baese metal alloys of the type which are used in the porcelain-fused-to-metal technic in dental prosthetics.Type: GrantFiled: June 7, 1982Date of Patent: August 16, 1983Assignee: Williams Gold Refining Company IncorporatedInventors: Dwarika P. Agarwal, Clyde E. Ingersoll
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Patent number: 4249943Abstract: An alloy composition for dental use containing, by weight, aluminum 0-3.0%, cobalt 0-20.0%, chromium 10.0-20.0%, manganese 0-1.5%, molybdenum 6.0-18.0%, nickel 58.5-77.0% and silicon 0-2.0%. The alloy retains the corrosion resistance properties found in nickel-chromium base alloys while having reduced yield strength typical of gold alloys thereby resulting in greater ease of grinding, polishing and manipulation. The alloy finds use as a porcelain substrate alloy and also as a crown and bridge or partial denture alloy.Type: GrantFiled: October 11, 1978Date of Patent: February 10, 1981Assignee: Williams Gold Refining Company IncorporatedInventors: M. Hamdi A. Mohammed, Dwarika P. Agarwal, Clyde E. Ingersoll