Patent ID: 11906482
Assignee: CORNING INCORPORATED
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An apparatus for testing edge strength of a sheet of material having a maximum width, the apparatus comprising:
a plurality of assemblies comprising two opposing assemblies, wherein a first of the two opposing assemblies comprises a single cylindrical roller member for engaging a first side of the sheet, and a second of the two opposing assemblies comprises two spaced-apart cylindrical roller members for engaging a second side of the sheet opposite the first side and selectively applying a 3-point bending load on the sheet of material in a test region of the apparatus, whereby the plurality of assemblies can establish a loaded condition on the sheet of material in the test region by applying the 3-point bending load and establish a no-load condition on the sheet of material in the test region by not applying the 3-point bending load;
wherein each of the cylindrical roller members are longer than the maximum width of the sheet of material so that the full width of the sheet of material can be engaged by the three rollers;
wherein the cylindrical roller members are arranged so that their rolling axes are parallel to each other and equidistant from each other;
wherein the two spaced-apart roller members define the test region between the two spaced-apart roller members;
a detection mechanism configured to optically measure strain in the sheet of material in the test region when the sheet of material is in the no-load condition and when the sheet of material is in the loaded condition, wherein the strain in the loaded condition is produced by the 3-point bending load, wherein a pattern provided on the surface of the sheet of material in the test region facilitates optically measuring the strain in the sheet of material; and
a processor that is configured to determine stress in the sheet of material based on the measured strain.