# US 2021/0239584 A1 · Edge strength testing of free-form glass panel > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0239584 A1 - Document ID: US20210239584A1 - Status: Published application - Kind: A1 - Application number: 17/237,437 - Filed: 2021-04-22 - Published: 2021-08-05 - Earliest claimed: 2019-05-15 - Assignees: Corning Incorporated - Applicants: Corning Incorporated - Inventors: Gabriel Pierce Agnello; Chong Pyung An; Zhenxing Hu; Bosun Jang; Peter Knowles; Balamurugan Meenakshi Sundaram; Douglas Miles Noni, JR.; Richard Sean Priestley; Jamie Todd Westbrook - Web page: https://patentgrep.com/patent/US20210239584A1 ## CPC - G01N 3/20: by applying steady bending forces (G01N3/26, G01N3/28 take precedence) - G01N 3/068: {with optical indicating or recording means} - G01N 2203/0023: Bending - G01N 2203/0282: Two dimensional, e.g. tapes, webs, sheets, strips, disks or membranes - G01N 2203/0647: Image analysis - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract An apparatus for testing the edge strength of a discrete sheet of material such as glass where the sheet has an irregular free-form shaped outline is disclosed. The apparatus can include a plurality of assemblies configured for selectively applying a 3-point bending load on an edge of the sheet of material in a test region of the apparatus, a detection mechanism that optically measures strain in the sheet of material in the region, and a processor that determines the stress in the sheet based on the measured strain by calculating the stress that would be required to produce the measured strain in the sheet of material. ## Claims ### Claim 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; and a processor that is configured to determine stress in the sheet of material based on the measured strain. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the single roller member is vertically aligned between the two spaced-apart roller members. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the detection mechanism comprises a first pair of cameras positioned to acquire one or more images of surface of the second side of the sheet in the test region between the two spaced-apart roller members, wherein the detection mechanism optically measures the strain in the sheet of material from the image of the surface of the second side of the sheet acquired using the first pair of cameras. ### Claim 4 (depends on 1) The apparatus of claim 1, 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. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the detection mechanism further comprises a second pair of cameras positioned to acquire an image of the surface of the second side of the sheet at a region other than the test region. ### Claim 6 (depends on 1) The apparatus of claim 1, further comprising two additional roller members positioned on the same side of the sheet as the single roller member and engaging the first side of the sheet of material. ### Claim 7 An apparatus for testing edge strength of a sheet of material comprising: a plurality of assemblies configured to selectively applying a 3-point bending load along an edge of 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 the plurality of assemblies comprises two opposing assemblies for applying the 3-point bending load, wherein a first of the two opposing assemblies comprises a single arcuate member for engaging a first side of the sheet and a second of the two opposing assemblies comprises two spaced-apart arcuate members for engaging a second side of the sheet opposite the first side, wherein the two spaced-apart arcuate members define the test region between the two spaced-apart arcuate members; a linear cam representing a linear map of the 3-point bending load along the edge of the sheet of material, wherein the linear cam is configured to move linearly in synchronization with the sheet of material; and a follower that rides on the linear cam, wherein the follower is connected to the single arcuate member to vary the 3-point bending load on the sheet of material as the sheet of material moves through the test region. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the single arcuate member is vertically aligned between the two spaced-apart arcuate members. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein the arcuate members are spherical bearings that enable in-plane translation of the sheet of material. ### Claim 10 (depends on 7) The apparatus of claim 7, further comprising: a detection mechanism configured for optically measuring 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; and a processor that is configured for determining stress in the sheet of material based on the measured strain. ### Claim 11 (depends on 8) The apparatus of claim 8, wherein the detection mechanism comprises a first pair of cameras positioned to acquire one or more images of the surface of the second side of the sheet in the test region between the two spaced-apart arcuate members, wherein the detection mechanism optically measures the strain in the sheet of material from the image of the surface of the second side of the sheet acquired using the first pair of cameras. ### Claim 12 (depends on 8) The apparatus of claim 8, wherein a pattern provided on the surface of the sheet in the test region facilitates optically measuring the strain in the sheet of material. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein the detection mechanism further comprises a second pair of cameras positioned to acquire an image of the surface of the second side of the sheet at a region other than the test region. ### Claim 14 An apparatus for testing edge strength of a sheet of material comprising: a plurality of assemblies configured for selectively applying a 3-point bending load along an edge of 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 the plurality of assemblies comprises two opposing assemblies for applying the 3-point bending load, wherein a first of the two opposing assemblies comprises a single arcuate member for engaging a first side of the sheet and a second of the two opposing assemblies comprises two spaced-apart arcuate members for engaging a second side of the sheet opposite the first side, wherein the two spaced-apart arcuate members are separated by a predefined spacing, wherein the two spaced-apart arcuate members define the test region between the two spaced-apart arcuate members; wherein the single arcuate member is vertically aligned between the two spaced-apart arcuate members; wherein the two spaced-apart arcuate members are configured to dynamically adjust the predefined spacing between the two spaced-apart arcuate members to adjust the stress induced in the sheet in the test region while maintaining the vertical alignment of the single arcuate member with respect to the two spaced-apart arcuate member. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the arcuate members are spherical bearings that enable in-plane translation of the sheet of material. ### Claim 16 (depends on 14) The apparatus of claim 14, further comprising: 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; and a processor that is configured for determining stress in the sheet of material based on the measured strain. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the detection mechanism comprises a first pair of cameras positioned to acquire one or more images of the surface of the second side of the sheet in the test region between the two spaced-apart arcuate members, wherein the detection mechanism optically measures the strain in the sheet of material from the image of the surface of the second side of the sheet acquired using the first pair of cameras. ### Claim 18 (depends on 16) The apparatus of claim 16, wherein a pattern provided on the surface of the sheet in the test region facilitates optically measuring the strain in the sheet of material. ### Claim 19 (depends on 17) The apparatus of claim 17, wherein the detection mechanism further comprises a second pair of cameras positioned to acquire an image of the surface of the second side of the sheet at a region other than the test region. ### Claim 20 An apparatus for testing edge strength of a sheet of material having an irregular shaped outline that defines a continuous edge along the irregular shaped outline, the apparatus comprising: a plurality of assemblies configured to selectively applying a 3-point bending load on a portion of the edge of 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 the plurality of assemblies comprises two opposing assemblies for applying the 3-point bending load, wherein a first of the two opposing assemblies comprises a single arcuate member for engaging a first side of the sheet and a second of the two opposing assemblies comprises two spaced-apart arcuate members for engaging a second side of the sheet opposite the first side, wherein the two spaced-apart arcuate members define the test region between the two spaced-apart arcuate members; a holder configured to holding the sheet of material while the 3-point bending load is being applied on the sheet of material; wherein the holder is configured to move the sheet of material so that a defined testing channel region along the edge of the sheet can be moved through the test region of the apparatus so that the 3-point bending load can be applied at different locations along the edge of the sheet; and wherein the holder is configured to guide the movement of the sheet material to maintain the defined region along the edge of the sheet within the test region as the defined region of the sheet is being moved through the test region. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the holder comprises a top side and a bottom side, wherein the top side is configured to receive and hold the sheet of material; and the holder comprises an outline of its periphery that mimics the irregular shaped periphery of the sheet of material in a proportionally smaller scale so that when the sheet of material is centered on the top side, a portion of the sheet of material overhangs the holder around the irregular shaped periphery, wherein the portion of the sheet that overhangs forms the defined testing channel region. ### Claim 22 (depends on 21) The apparatus of claim 21, wherein the holder comprises a guiding groove around its perimeter side wall, and the plurality of assemblies comprise a complementary stylus that follows the guiding groove, whereby the two opposing assemblies for applying the 3-point bending load can follow and maintain the defined testing channel region in the test region. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the holder is configured to hold the sheet material by vacuum, adhesive, or mechanical restraints. ### Claim 24 An apparatus for testing edge strength of a sheet of material having an irregular shaped periphery that defines a continuous edge along the irregular shaped periphery, the apparatus comprising: a holder configured to holding the sheet of material, wherein when the holder is holding the sheet of material a testing channel region is defined along the continuous edge of the sheet; and a plurality of assemblies configured to selectively applying a 3-point bending load on a portion of the testing channel region of the continuous edge of 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 the plurality of assemblies comprises two opposing assemblies for applying the 3-point bending load on the portion of the continuous edge of the sheet of material in the test region while the portion of the continuous edge of the sheet of material is positioned between the two opposing assemblies, wherein a first of the two opposing assemblies comprises a single arcuate member for engaging a first side of the sheet and a second of the two opposing assemblies comprises two spaced-apart arcuate members for engaging a second side of the sheet opposite the first side, wherein the two spaced-apart arcuate members define the test region between the two spaced-apart arcuate members, and wherein the plurality of assemblies are configured to be moved around the perimeter of the discrete sheet of material following the irregular shaped periphery, whereby the testing channel region of the continuous edge of the sheet of material is maintained between the two opposing assemblies during the movement. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein the apparatus comprises a computer processor and the movement of the plurality of assemblies is controlled by the computer processor. ### Claim 26 (depends on 25) The apparatus of claim 25, wherein the apparatus comprises a non-transitory computer readable medium storing information on the irregular shaped periphery of the sheet of material, wherein the computer processor controls the movement of the plurality of assemblies based on the information on the irregular shaped periphery of the sheet of material. ### Claim 27 (depends on 24) The apparatus of claim 24, wherein the movement of the plurality of assemblies can be continuous or stepped. ### Claim 28 (depends on 24) The apparatus of claim 24, wherein the holder comprises a vacuum plate for holding the discrete sheet of material.