Abstract 1. A method of controlling to within a desired tolerance the contour of a thermoplastic sheet shaped while heat-softened by press bending apparatus, comprising the steps of : determining a radius of curvature for preselected regions of a shaped sheet from the coordinates of at least three points associated with a least one of said preselected regions, establishing a reference radius of curvature for corresponding preselected regions and points associated with a reference surface; comparing each said radius of curvature determined for said preselected regions with the radius of curvature established for corresponding regions of said reference surface, selecting a region of said sheet whose radius of curvature so determined differs from the radius of curvature established for its corresponding region of said reference surface sufficiently to make adjustment of the radius of curvature of said selected region desirable, determining an adjustment to said press being apparatus which reduces the difference in radius of curvature for said selected region from the established for said corresponding region while simultaneously maintaining the contour of other regions of said sheet to within said desired tolerance, adjusting said press bending apparatus according to said determination, and shaping subsequent sheets by said adjusted press bending apparatus.
A method of controlling to within a desired tolerance the contour of a thermoplastic sheet shaped while heat-softened by press bending apparatus, comprising the steps of : determining a radius of curvature for preselected regions of a shaped sheet from the coordinates of at least three points associated with a least one of said preselected regions, establishing a reference radius of curvature for corresponding preselected regions and points associated with a reference surface; comparing each said radius of curvature determined for said preselected regions with the radius of curvature established for corresponding regions of said reference surface, selecting a region of said sheet whose radius of curvature so determined differs from the radius of curvature established for its corresponding region of said reference surface sufficiently to make adjustment of the radius of curvature of said selected region desirable, determining an adjustment to said press being apparatus which reduces the difference in radius of curvature for said selected region from the established for said corresponding region while simultaneously maintaining the contour of other regions of said sheet to within said desired tolerance, adjusting said press bending apparatus according to said determination, and shaping subsequent sheets by said adjusted press bending apparatus.
Claim 2
Independent Claim
200 words
A method of controlling to within a desired tolerance the contour of a thermoplastic sheet shaped while heat-softened by press bending apparatus, comprising the steps of : determining a radius of curvature for preselected regions of a shaped sheet from the coordinates of at least three points associated with a least one of said preselected regions, establishing a reference radius of curvature for corresponding preselected regions and points associated with a reference surface; comparing each said radius of curvature determined for said preselected regions with the radius of curvature established for corresponding regions of said reference surface, selecting a region of said sheet whose radius of curvature so determined differs from the radius of curvature established for its corresponding region of said reference surface sufficiently to make adjustment of the radius of curvature of said selected region desirable, determining an adjustment to said press being apparatus which reduces the difference in radius of curvature for said selected region from the established for said corresponding region while simultaneously maintaining the contour of other regions of said sheet to within said desired tolerance, adjusting said press bending apparatus according to said determination, and shaping subsequent sheets by said adjusted press bending apparatus.