Process and apparatus for the production of spectacle frame parts of synthetic material
AssigneeEssilor International Cie Generale d'Optique
InventorsMichel Coulon, Gerard Laprade
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Abstract
The invention relates to the production of spectacle frame parts of synthetic material and in particular to the moulding of spectacle frame faces of synthetic material, for example, of polyurethane. The faces are moulded between two casting half-moulds each comprising a plate having an impression on one surface thereof. Each plate has a substantially equal thickness at every point and is made of a polyolefine. Use of such half-moulds enables the faces of spectacle frames to be directly moulded into their final shape.
Claims15
A process for producing casting half-moulds for fabricating spectacle frame parts of synthetic material having complex, curved three-dimensional configuration with undercut portions, said process comprising the steps of providing injection half-moulds having impressions which are respectively negative and positive replicas of the shape of the ultimate spectacle frame part of curved complex three-dimensional configuration, and injecting homopolymers and copolymers of polyolefins into the cavity defined by the injection half-moulds, and removing the resulting injection moulded casting half-mould of substantially uniform thickness throughout from the cavity.
A process of producing spectacle frame parts of complex, curved three-dimensional configuration with undercut portions, said process comprising the steps of providing two complementary half-moulds, defining in one face of each half-mould an impression which is the negative replica of the complex, curved three-dimensional configuration of the spectacle frame part to be cast and in the opposite face a positive replica of the part to be cast, the thickness of each of the half-moulds being substantially uniform throughout, positioning the half-moulds in casting relationship so as to define a casting cavity which is a negative replica of the part to be cast, casting material in the cavity so defined and removing the casting from the cavity in its ultimate complex, curved three-dimensional configuration with undercut portions.
A casting half-mould for casting plastic spectacle parts, in particular spectacle fronts, in their final complex, curved three-dimensional configuration with undercut portions, said half-mould comprising a plate made of homopolymers and copolymers of polyolefin and having one face including an impression defining the negative replica of the complex, curved three-dimensional spectacle part configuration with undercut portions, the opposite face defining the positive replica of said configuration, and the thickness of said plate being substantially uniform throughout.
Dependencies are inferred from the claim text.