Mold separation method and apparatus
AssigneeJohnson & Johnson Vision Products, Inc.
InventorsTure Kindt-Larsen, Stephen Robert Beaton, Wallace Anthony Martin, Stephen Craig Pegram, Craig William Walker
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Abstract
An apparatus for separating individual contact lens mold assemblies, the assemblies each being a front curve mold half and a back curve mold half, each mold half having annular circumferential flanges, is included. The apparatus includes a device for applying steam to the back curve mold half to form a temperature gradient from the front mold half to the back mold half. The apparatus also includes a second device to pry the mold halves apart.
Claims51
An apparatus for separating individual contact lens mold assemblies, each of said assemblies having a contact lens mold between a front curve half and a back curve mold half, each of said mold halves having circular circumferential flanges, said apparatus comprising:
- (a) first means for applying steam at a first temperature to said back curve mold half to form a temperature gradient between said back mold half relative to said front curve mold half, wherein said temperature gradient ranges from about 2.5.degree. C. to 6.0.degree. C.;
- and,
- (b) second means for demolding, said means including a prying means inserted between said circular circumferential flanges of each said front mold and back mold halves of said contact lens mold assembly, said prying means including a second set of pry fingers for retaining said front curve mold half and a first set of pry fingers for biasing said back curve mold half upwardly at a predetermined force with respect to said front curve mold half to effectively remove said back mold half therefrom;
- and
- (c) third means for controlling the temperature of a convex surface of said front mold half.
An apparatus for separating a back mold half from a front mold half of a contact lens mold assembly useful in the production of a contact lens, each said front and back mold halves having a central curved section defining a concave surface, a convex surface, and a circular circumferential flange, at least part of at least one of said concave surface and said convex surface having the dimensions of the front or back curve, respectively, of a contact lens to be produced in said mold assembly, said apparatus comprising:
- (a) means for applying steam to said concave surface of said back mold half while maintaining said convex surface of said front mold half at a first temperature to form a temperature gradient between said convex surface of said back mold half and said concave surface of said front mold half, and, resultingly, a temperature gradient across said contact lens, wherein said temperature gradient ranges from about 2.5.degree. C. to 6.0.degree. C.;
- and,
- (b) prying means for insertion between said circular circumferential flanges of each said front mold and back mold halves of said contact lens mold assembly, said prying means including a first and second sets of pry fingers for biasing said back mold half upwardly at a predetermined force with respect to said front mold half to effectively remove said back mold half therefrom.
A method of separating a back mold half from a front mold half of a contact lens mold assembly useful in the production of a contact lens, each said front and back mold halves having a central curved section defining a concave surface, a convex surface, and a circular circumferential flange, at least part of at least one of said concave surface and said convex surface having the dimensions of the front or back curve, respectively, of a contact lens to be produced in said mold assembly, said method comprising the steps of:
- (a) inserting a first set of pry fingers between said circular circumferential flanges of each said front mold and back mold halves of said contact lens mold assembly;
- (b) applying a predetermined amount of steam to said back curve lens mold surface to form a temperature gradient between said back mold half relative to said front mold half, wherein said temperature gradient ranges from about 2.5.degree. C. to 6.degree. C.;
- and
- (c) biasing said first set of pry fingers in a substantially vertical direction so as to simultaneously remove said back curve lens mold half from its associated front curve lens mold half.
An apparatus for demolding a contact lens molded between a concave front curve mold half and a convex back curve mold half, each of said halves having an outwardly extending flange member, which flange members are spaced from and substantially parallel to each other, said apparatus comprising:
- (a) at least one pair of lower pry fingers, said pair joined together at a bight to form lower U-shaped pry tool;
- (b) at least one pair of upper pry fingers, said pair joined together at a bight to form an upper U-shaped pry tool;
- (c) first means for reciprocating said upper and lower pry tools along an insertion axis from a first conveying position to a second insertion position;
- (d) second means for reciprocating said upper and lower pry tools along a first pry axis from a first insertion position to a second demolded position;
- (e) control means for sequentially actuating said first means to insert said pry tools between the flange members of said mold, and then actuating said second means to lift said back curve mold half upwardly to thereby separate said back curve mold half from said front curve mold half;
- and
- (f) a steam heating means to heat said back curve mold half before said second means is actuated, the heating means being sufficient to heat the back curve mold half to a temperature of from about 2.5.degree. C. to about 6.0.degree. C. above the front curve mold half.
Dependencies are inferred from the claim text.