| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a protective ring from sliding down by a nonskid uneven strip part when the protective ring is gripped and held up, to prevent the protective ring from horizontally sliding and jumping out because of the presence of the nonskid uneven strip part by gripping a plurality of nonskid grip parts, and to prevent the protective ring and a reference gauge hole of a ring gauge from being damaged by an external force of collision or the like.SOLUTION: A protective ring 3 is disposed in an outer peripheral part of a ring gauge 1 including a reference gauge hole 2 to be a reference for various measuring instruments. On an outer peripheral surface of the protective ring, an annular nonskid uneven strip part 4 is formed for preventing the protective ring from sliding down when the protective ring is held up by gripping its outer peripheral surface. On the outer peripheral surface of the protective ring, a plurality of nonskid grip parts 5 are formed for preventing the protective ring from horizontally sliding and jumping out because of the presence of the annular nonskid uneven strip part when the outer peripheral surface of the protective ring placed on a surface plate J is gripped.</p> |
