Method and apparatus for centrifugal casting of contact lenses in open molds

According to the method of the invention, molds charged with a monomer mixture are arranged into columns with precisely coaxial casting surfaces inside these columns, namely, in tubes of cylindric shape with openings only 0.01 to 0.03 mm larger the diameter of the outer cylindric surface of the mold...

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Bibliographische Detailangaben
Hauptverfasser:	WICHTERLE, OTTO
Format:	Patent
Sprache:	eng
Schlagworte:	AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING CONTACT LENSES GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS OPTICS PERFORMING OPERATIONS PHYSICS PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCESIN A PLASTIC STATE SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR SHAPING OR JOINING OF PLASTICS SPECTACLES SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURESAS SPECTACLES TECHNICAL SUBJECTS COVERED BY FORMER USPC TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS TRANSPORTING WORKING OF PLASTICS WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL
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Beschreibung
Zusammenfassung:	According to the method of the invention, molds charged with a monomer mixture are arranged into columns with precisely coaxial casting surfaces inside these columns, namely, in tubes of cylindric shape with openings only 0.01 to 0.03 mm larger the diameter of the outer cylindric surface of the mold or the diameter of a hypothetical cylindrical surface circumscribed to any other, preferably a parallel outer surface of the casting mold. The tube with the inserted column of molds is provided with airtight seals at both ends whereas at least one seal is provided with a valve for alternating evacuation and refilling with an inert gas. The invention also provides apparatus by which a complete sequence of required operations including column tilting and rotation is carried out with the tubes charged in this way until the polymerization is completed without transferring the molds from sealed tubes from one apparatus to another or into intermediate magazines.