A method and apparatus increasing the accuracy of the two ball or wire measurement of pitch diameter, simple pitch diameter and virtual pitch diameter of internal and external screw threads and thread gauges.

摘要

A method and apparatus increasing the accuracy of effective pitch diameter, simple pitch diameter and virtual pitch diameter of internal and external screw threads and thread gauges. The well-known two ball or wire measurement with an one axis universal length measurement machine is combined with the actual pitch and actual flank angles of the thread profile derived from the contour-scan of the thread profile with an one-sided contour scanner. Applied is an one-sided contour scanner for measuring the actual pitch and actual flank angles of the thread profile in combination with the distance over the probing elements as measured with an one-axis length measuring machine. The measuring results from both instruments are transferred to a special computer- and software-system for acquisition and processing to effective pitch diameter, simple pitch diameter and virtual pitch diameter.