Back to results
US 4,538,590 AGranted
Cookware having integrally formed natural stone bottoms and method of manufacturing the same
AssigneeJ & L Importers, Inc.
InventorChang H. Oh
Life of this patent
Estimating the term…
Abstract
Improved cookware is disclosed having non-ferrous metal sidewalls and a natural stone bottom central portion. The non-ferrous metal sidewalls preferably are formed of an aluminum alloy having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of the natural stone bottom. The natural stone bottom preferably comprises an iron-rich amphibole rock, and in the particularly preferred embodiment comprises hornblende.
Claims5
A method of forming a cooking utensil comprising the steps of:
- (a) providing a substantially flat bottom portion of natural stone;
- (b) machining said natural stone bottom portion to form an outwardly extending peripheral lip about the perimeter thereof;
- (c) heating said bottom portion to a temperature of from about 200.degree. C. to about 300.degree. C. for stress relief;
- (d) thereafter heating said stress relieved bottom portion to a temperature of about 200.degree. C. for a period exceeding four minutes;
- (e) placing said bottom portion in a mold;
- and
- (f) casting an aluminum alloy about said bottom portion to form a metal sidewall of said utensil, said bottom portion having a coefficient of thermal expansion substantially equal to the coefficient of thermal expansion of said metal sidewall.
4 more elements
Dependencies are inferred from the claim text.