Hole center detecting apparatus, straightness measuring apparatus and residual torsion measuring apparatus

摘要

A hole center detecting apparatus for positioning the hole of a spool and a cord accurately by determining the coordinates of two points of intersection between the inner circumference of the spool hole and a virtual straight line to compute the coordinates of the center of the hole and by moving the cord according to the computed coordinates of the hole center. A straightness measuring apparatus for measuring the curvature of a cord automatically by detecting the coordinates of three longitudinal points of the cord. A measurement apparatus for measuring a residual torsion automatically by measuring the rotation angle of the end portion of the cord before and after clamped, electrically.