Wedge demolding of cast lens mold assemblies

• Main Authors: WIDMAN, MICHAEL F, WANG, DANIEL TSU-FANG, DAGOBERT, HENRI A
• Format: Patent
• Language: English; French; German
• Published: 11.06.2003
• Edition: 7
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CONTACT LENSES; INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULARARTICLES; 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; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

Demolding apparatus for reliably and repeatedly mechanically separating contact lens mold assemblies without damaging the contact lens formed therebetween. The mold assembly includes a frontcurve mold having a central mold section with a surrounding flange, and a corresponding backcurve mold also having a central mold section with a surrounding flange, with a contact lens being molded therebetween. A support pallet is provided for supporting the mold assembly. A wedge separating fixture provides at least one separating wedge positioned between the spaced flanges of the mold assembly, and the wedge separating fixture and support pallet are translated relative to each other to progressively separate the frontcurve mold from the backcurve mold. In one embodiment the wedge separating fixture is stationarily mounted suspended above the support pallet, and a drive conveys the support pallet relative to the stationarily mounted wedge separating fixture to a position whereat the separating wedge is positioned between the spaced flanges of the mold assembly and separates or demolds the frontcurve and backcurve molds. In several preferred embodiments, the support pallet supports an n x m array mold assemblies. In alternative embodiments, the wedge separating fixture can include one separating fixture can include one separating wedge for each row for the n x m array, or two separating wedges for each row, one positioned on each side of the row. In alternative embodiments, the n x m array of mold assemblies can include a mold frame which interconnects an n x m array of frontcurve molds, an n x m array of individual unconnected frontcurve molds, with an individual backcurve mold placed over each frontcurve mold.