Apparatus for determining hardness of O-rings, subjects O-ring lying on surface to indentation pressure from cylinder with axis parallel to resting surface

摘要

An O-ring, placed on a resting surface, is subjected to indentation pressure from a cylinder with its axis parallel to the resting surface. The curvature of the cylinder or rod, is continuous about the axis. The cylindrical section length is at least three times the minimum radius of curvature of the pressure surface and preferably at least twice the diameter of the O-ring strand. The cylinder length is preferably at least 2 mm. It exceeds the maximum diameter across the largest O-ring test sample. It is unbroken over its entire length. Several cylindrical sections are provided, all of the same curvature. There may be two or more, with axes in alignment, on either side of a central vertical axis. Numbers of cylinders may be pressed simultaneously across the strand of a single O-ring. An independent claim is included for a corresponding process for determining a value for the hardness of O-rings.