Abstract: A lens generator device is provided with a dynamic electronic braking circuit for instantaneously interrupting operation of the lens generated under certain conditions to prevent injury to an operator. The lens generator includes a chamber structure having an access cover and having a power driven grinding tool therein. A photoelectric switch is mounted on the tailstock in confronting relation with the chamber structure cover and is operable when the cover is raised or when the tailstock is retracted to operate the dynamic braking circuit and instantaneously stop operation of the grinding tool.

Abstract: A process and apparatus for dry lens generation of a plastic optical lens includes a chamber structure in which the lens grinding tool and the lens blank holder are positioned. The chamber is provided with a large unobstructed inlet and an outlet connected in communicating relation to a vacuum system so that the high volume, high velocity stream of ambient air is directed across the interface between the grinding tool and the lens blank to thereby entrain the cut plastic material in the stream for evacuation through the outlet. The grinding tool is diamond plated and the spacing between the diamond elements is of a sufficient magnitude to permit single point cutting of the material to thereby eliminate any tendency of the material to adhere to the grinding tool. A misting nozzle discharges a fine lubricating mist across the lens blank grinding tool interface when a lens is being formed from polycarbonate.

Abstract: A process and apparatus for dry lens generation of a plastic optical lens includes a chamber structure in which the lens grinding tool and the lens blank holder are positioned. The chamber is provided with a large unobstructed inlet and an outlet connected in communicating relation to a vacuum system so that the high volume, high velocity stream of ambient air is directed across the interface between the grinding tool and the lens blank to thereby entrain the cut plastic material in the stream for evacuation through the outlet. The grinding tool is diamond plated and the spacing between the diamond elements is of a sufficient magnitude to permit single point cutting of the material to thereby eliminate any tendency of the material to adhere to the grinding tool. A misting nozzle discharges a fine lubricating mist across the lens blank grinding tool interface when a lens is being formed from polycarbonate.