Apparatus and method for releasing a lens molded in a cavity between posterior and anterior mold sections
View Patent ↗An apparatus and method for releasing a lens molded in a cavity between posterior and anterior mold sections and adhered thereto. A post is configured to support a flange of the posterior section while the anterior section remains spaced from the post. Posterior section is compressed between a pin applied to an outer concave surface of the posterior section and the post, thereby initially releasing peripheral regions of the posterior section and subsequently the remaining portions thereof. Upon separation, the anterior section together with the lens drops onto the post so that its outer convex surface rests on the post. A collar unit with gas channels presses against a flange of the anterior section while blowing jets of gas towards an interface between a “monomer” ring formed around the lens. In this manner, initially the “monomer” ring and then peripheral regions of the lens are separated from the anterior section.
1. A device for separating a posterior mold section from an anterior mold section wherein a cured lens is adhered to corresponding molding surfaces of the mold sections, the device comprising:
a support post having a longitudinal axis;
a first support element positioned on the post radially outwardly spaced from the longitudinal axis, the first support element comprising a first face adapted to provide support for at least a peripheral portion of a flange projecting from a skirt portion of the posterior mold section;
a pressing means for applying a longitudinally directed force to a central area of an outer concave surface of the posterior mold section, when the flange of posterior mold section rests on the first face;
the longitudinally directed force being sufficient to compress and deform the posterior mold section between the pressing means and the first face thereby breaking an adhesive bond between the lens and the posterior mold section, starting around peripheral regions of the lens and continuing towards the center of the lens, thereby separating the posterior mold section from the anterior mold section, wherein the pressing means comprises a pin having a free end, wherein the pin is movable and the support post remains stationary, wherein the first support element comprises a radially inwardly directed face and wherein the device further comprises:
a second support element positioned substantially centrally on the post, the second support element comprising a second face for supporting the anterior mold section, and a radially outwardly directed face;
a as defined between the radially inwardly facing face of the first support element and the radially outwardly directed face of the second support element, the gap being configured to receive a skirt portion depending from the anterior mold section; and
wherein the first and second support elements are configured with respect to the mold so that when the posterior mold section rests on the first face, the anterior mold section is longitudinally spaced apart from the second support element, wherein the first and second faces are spaced from each other along the longitudinal axis so that when the posterior mold section rests on the first face, the second face is spaced apart to the anterior mold section, wherein the first and second support elements are immovable with respect to each other.
2. A device as claimed in claim 1 , wherein the gap is configured so as to accommodate a flange projecting from the skirt portion of the anterior mold section.
3. A device as claimed in claim 2 , wherein the second support element is configured with respect to the skirt portion of the anterior mold section so as to be received within the skirt portion.
4. A device as claimed in claim 3 , wherein the second support element is configured with respect to the skirt portion of the anterior mold section so that when the second support element is received within the skirt, sufficient spacing is provided between inner surfaces of the skirt and outer surfaces of the second support element to provide clearance for deformation of the skirt in the radial direction.
5. A device as claimed in claim 4 , wherein the second face is configured to abut an outer convex surface of the anterior mold section.
6. A device as claimed in claim 5 , wherein the second face is in a form of an annular surface surrounding an aperture formed in the second support element such that when the outer convex surface of the anterior mold section abuts the annular surface, a portion of the outer convex surface projects into the aperture, the aperture being sized and shaped so that the outer convex surface remains spaced apart from surfaces defining the aperture.
7. A device as claimed in claim 6 , wherein the aperture of the second support element is in a form of a bore.
8. A device as claimed in claim 7 , wherein the first support element comprises a pair of diametrically opposing shoulders.
9. A device as claimed in claim 8 , wherein the shoulders are arcuate.
10. A device as claimed in claim 9 , wherein each shoulder comprises a slot formed in the radially inwardly directed face, the slot being configured to receive at least a peripheral portion of the flange of the anterior mold section when the anterior mold section rests on the second face upon radial outward deflection of adjacent portions of the skirt of the anterior mold section.
11. A device as claimed in claim 10 , wherein the second support element comprises of a pillar located substantially centrally between the shoulders.
12. A device as claimed in claim 11 , wherein the second face comprises a chamfer formed between an end surface of the pillar and an inner surface defining the aperture.
13. A device as claimed in claim 12 , wherein the pillar comprises a pair of diametrically opposing flats on an outer surface of the pillar so as to provide a clearance for radial inward deformation of the skirt of the anterior mold section when the anterior mold section rests on the second face.
14. A device as claimed in claim 13 , wherein the second support element and the gap between the radially inwardly directed face of the first support element and the radially outwardly directed face of the second support element are configured with respect to the anterior mold section so that when the anterior mold section rests on the second face, the flange of the skirt of the anterior mold section is suspended within the gap.
15. A device as claimed in claim 14 , comprising a means for supplying at least one jet of gas directed at an interface between a rim of excess expelled lens material formed around peripheral regions of the lens and adhered to a surface of the anterior mold section surrounding the lens, the force of the jet being sufficient to break the adhesive bond between the excess lens material and the surface and thereby separate this excess material from the mold section.
16. A device as claimed in claim 15 , comprising a pressing means for applying a longitudinally directed force to a radially extending flange of the skirt of the anterior mold section, when the anterior mold section rests on the second face.
17. A device as claimed in claim 16 , adapted to apply a force sufficient to cause a surface of the anterior mold section surrounding the lens to deflect in the direction of the force thereby at least partially breaking an adhesive bond between the excess lens material and the surface.
18. A device as claimed in claim 17 , wherein the force is sufficient to cause a concave surface of the anterior mold section to which the cured lens is adhered to deflect in the direction of the force thereby breaking the adhesive bond between the lens and the concave surface at least about peripheral regions of the lens, starting from an outer edge of the lens and continuing in the direction of the center of the lens.