Lens impact hammer apparatus and methods
US3999420A · kind A · utility
Inventor
Key dates
| Filing date | Feb 26, 1975 |
| Grant date | Dec 28, 1976 |
| Priority date | — |
| Expiry date | Feb 26, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2203/0039
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Hammer apparatus is provided for impacting an eyeglass lens to test the frangibility of the lens. A hammer arm is pivotally mounted on a base plate for rotation between a vertical position and a horizontal position. A steel ball is connected to the end of the hammer arm to impact the lens. A weight is positioned precisely on the hammer arm to provide the exact amount of impact force required by FDA regulations. A cylindrical pedestal is mounted to the base plate to support the lens horizontally so that the ball strikes substantially in the center of the lens when the hammer arm falls to the horizontal position. A catch member holds the hammer arm in the vertical position and, upon manual actuation, the catch member releases the hammer arm to fall to impact the lens. A removable metal box encloses the pedestal for catching broken glass. The top of the box includes an aperture for the ball to enter as the arm falls to impact the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.