Patent ID: 6276920
Filing Date: 2001-08-21
Classification: B29D,B29L,Y10S

Abstract:
A mold assembly having a mold cavity to be filled with a liquid monomer composition which is polymerized to form a lens blank for use in manufacturing a desired ophthalmic lens, comprising:an upper mold including a substantially cylindrical body portion, an outward flange portion extending radially outwardly from one of axially opposite ends of said body portion, and an annular engaging portion which extends from said outward flange portion in an axial direction thereof from said one of said axially opposite ends of said body portion toward the other of said axially opposite ends, said annular engaging portion having an outer surface;a lower mold having a tapered outer surface; andan intermediate sleeve for removably connecting said upper and lower molds, said intermediate sleeve including a lower portion, an upper portion and an intermediate portion located between said lower and upper portions, said lower portion having a lower tapered inner surface for press-fitting engagement with said tapered outer surface of said lower mold, to effect fluid-tight connection of said lower mold and said intermediate sleeve,said upper portion of said intermediate sleeve having an upper tapered inner surface whose diameter is larger than an inside diameter of an inner surface of said intermediate portion, said intermediate sleeve further including a shoulder between said upper tapered inner surface of said upper portion and said inner surface of said intermediate portion,said outer surface of said annular engaging portion of said upper mold being provided for press-fitting engagement with said tipper tapered inner surface of said intermediate sleeve, to effect fluid-tight connection of said upper mold and said intermediate sleeve, with said body portion of said upper mold being held in abutting contact with said shoulder in an axial direction of said intermediate sleeve, such that said upper mold and said intermediate sleeve cooperate with said lower mold to define said mold cavity, with said tapered outer surface of said lower mold being held in press-fitting engagement with said lower tapered inner surface of said intermediate sleeve,said press-fitting engagement of said outer surface of said annular engaging portion of said tipper mold with said upper tapered inner surface of said intermediate sleeve cooperating with said abutting contact of said body portion with said shoulder, to define a liquid reservoir for storing an excess amount of said liquid monomer composition which has been discharged from said mold cavity when said mold cavity is defined by fluid-tight connection of said upper and lower molds to said intermediate sleeve,said annular engaging portion having an inside diameter larger than an outside diameter of said cylindrical portion, for thereby cooperating with said cylindrical portion to define an annular reservoir which has a predetermined radial dimension and which provides at least a part of said liquid reservoir,said intermediate sleeve and said lower mold cooperating to provide a stopper for determining a relative axial position therebetween.