Abstract: Coating of the convex side of an optical lens for blocking purposes by spinning the lens about its vertical axis and dipping its downwardly facing convex side in a liquid coating material, stopping the rotation of the lens and upwardly withdrawing the lens above the level of the coating material, and spinning the upwardly withdrawn lens to spread the coating material by centrifugal force as a uniformly thin film over the convex side and to drive the film sufficiently for handling.To facilitate the lens coating operation, the lens is held on its upper concave side by a suction cup having the upper end of its vibration damping stem chucked in the drive shaft of a hand held motor housing. To further facilitate the lens coating operation despite leakage between the suction cup and the lens, the drive shaft has a passage therethrough communicating with a passage from the suction side of the suction cup through the stem and with a flexible suction tube leading to the suction port of a power vacuum motor.

Abstract: A suction cup of resilient rubber-like material having affixed on the peripheral portion of its suction side a ring gasket of soft pliable putty-like material adapted to form a vacuum tight space therewithin when pressed against a non-porous supporting surface despite imperfections or irregularities in the surface to retain the suction cup by vacuum and adhesion, the adhesion being less than the cohesive strength of the gasket to enable removal and reuse of the suction cup by release of vacuum therewithin and pulling away from the surface to which applied.

Abstract: Coating of the convex side of an optical lens for blocking purposes by dipping the downwardly facing convex side in a liquid coating material in a can, upwardly withdrawing the lens above the level of the coating material but below the lip of the can, and spinning the lens about its vertically disposed axis to spread the coating material by centrifugal force as a uniformly thin film over the convex side, to create an edge buildup of coating material to form a thickened bead-like peripheral or rim portion at the periphery of the convex side, and to spin-off excess coating material against the inside of the can for reuse. Upon spin-off of excess coating material the lens is withdrawn out of the can whereupon the film on the spinning lens dries sufficiently for handling within a few seconds time. The spinning operation is then discontinued and the lens may be positioned on a horizontal support with its coated convex side facing upwardly preparatory to blocking.