Patent ID: 6242926
Filing Date: 2001-06-05
Classification: G01B

Abstract:
A method for moving an article relative to and between a pair of distance sensing probes of a thickness measuring apparatus which are spaced apart a known distance D, wherein a line between the probes defines a common measurement axis A.sub.c and wherein the apparatus has means to move the article between the of probes in a plane normal to the common measurement axis A.sub.c and to move the article relative to the probes along the common measurement axis A.sub.c, the method comprising the steps of:(a) providing an article having a surface;(b) continuously moving the article relative to and between the pair of probes in at least one direction in the plane normal to the common measurement axis A.sub.c ;(c) continuously measuring a distance a along the common measurement axis A.sub.c between the first probe of the pair and a point on the surface of the article nearest to the first probe that intersects the common measurement axis A.sub.c and continuously measuring a distance b along the common measurement axis A.sub.c between the second probe and a point on the surface of the article nearest to the second probe that intersects the common measurement axis A.sub.c ; and(d) from the measured distance, continuously moving the article relative to the probes along the common measurement axis A.sub.c so as to minimize any difference between the measured distance a and a desired distance a.sub.d along the common measurement axis A.sub.c between the first probe and a point on the surface of the article nearest to the first probe that intersects the common measurement axis A.sub.c.