Abstract: A pair of mandrels crossing at a right angle are moved into the center of an O-ring and then spread apart to stretch the O-ring around the mandrels to secure it and to form it into a twisted path. The mandrels are rotated to drive the O-ring through the twisted path so that the angular orientation of any given cross section of the O-ring changes as it advances around the path. An optical measurement apparatus senses cross section diameter of the O-ring at several locations. A support for one of the mandrels accommodates a load cell to measure the force developed by stretching the O-ring to provide a measure of O-ring elasticity.

Abstract: A pair of mandrels crossing at a right angle are moved into the center of an O-ring and then spread apart to stretch the O-ring around the mandrels to secure it and to form it into a twisted path. The mandrels are rotated to drive the O-ring through the twisted path so that the angular orientation of any given cross section of the O-ring changes as it advances around the path. An optical measurement apparatus senses cross section diameter of the O-ring at several locations and frequently repeats the measurement during the O-ring movement. The diameters are electrically compared to determine dimensional anomalies in the O-ring.