Lens blocking apparatus

摘要

A blocking mechanism comprises a similified rotary dial mechanism and a lens clamp which automatically depressurizes a molten alloy tank in response to a release of the lens clamp pressure. A lens seat is provided with a raised resilient pad to accommodate the recessed portion of a bifocal lens. The application of final lens clamping pressure cannot occur until the lens clamp contacts the lens in order to assure that an operator's finger cannot become accidentally pinched.