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US 4,381,932 AGranted
Laminated gob for pressing glass articles
AssigneeCorning Glass Works
InventorsJohn H. Olson, Robert J. Schlaufman
Life of this patent
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AssigneeCorning Glass Works
InventorsJohn H. Olson, Robert J. Schlaufman
Estimating the term…
Method and apparatus is set forth for forming a laminated gob or charge of molten glass having a core glass which is not only completely surrounded by a skin glass but also has a reentrant portion of skin glass which projects inwardly within the core glass from the periphery of the molten charge intermediate its upper and lower extent. The reentrant portion of skin glass is formed within the charge during the gobbing cycle by momentarily retarding or retracting the outward flow of the core glass while simultaneously positively pulsing the flow of the skin glass. Thus, a laminated gob or charge of molten glass is formed which not only has a skin glass completely surrounding and encompassing a core glass but also has a reentrant portion of the skin glass which is continuous with the remainder of the skin glass surrounding the core glass. The reentrant skin glass portion of the gob projects within the inner more fluid core glass, such that when the charge is pressed into a glass article, the reentrant skin glass is forced outwardly with the flow of the hotter central core glass so as to form a continuous uniform skin about the extremeties of the pressed article.
A method of forming a laminated charge of molten glass having a core of one glass and a skin of a second glass which not only completely surrounds said core glass but has a reentrant portion extending inwardly within the core glass from a circumferential peripheral portion of such charge which comprises, providing a supply of molten core glass to a central portion of a discharge orifice, providing a separate supply of molten skin glass to said discharge orifice so as to surround the flow of core glass from a central portion of said orifice with said skin glass, applying a force to the core glass being supplied to the discharge orifice and thereby urging an increased flow of core glass from a central portion of said discharge orifice over that which would flow by gravity under a steady state condition while simultaneously permitting the skin glass supplied to said orifice to flow by gravity at a steady state rate about the flow of core glass, momentarily interrupting and reversing the force applied to said core glass and thus retarding the flow of core glass from the central portion of said discharge orifice while substantially simultaneously providing a pulsed force to the skin glass being supplied to said discharge orifice and thus urging the skin glass into a void created by the retarded core glass flow, resuming the force applied to the core glass supplied to the discharge orifice and substantially simultaneously terminating the pulsed force applied to the skin glass supplied to the discharge orifice, and severing the resultant laminated gob from the flow emanating from the discharge orifice in such a manner to form the laminated charge.
A method of forming a laminated gob of molten glass having a core of one glass completely surrounded by a skin of a second glass and having a reentrant portion of said skin glass projecting radially inwardly within said first core glass from a circumferential peripheral portion of said gob intermediate the upper and lower extent of the gob which comprises, simultaneously delivering a first flow of core glass and a second flow of skin glass which surrounds said core glass from a discharge orifice;
Dependencies are inferred from the claim text.