Patent ID: 9372061
Filing Date: 2016-06-21
CPC Classification: G01B

Claim Text:
1. An inner diameter measuring device for measuring an inner diameter of a hollow object to be measured, wherein said inner diameter measuring device comprises a circulation unit and a measuring head and is insertable into inside of an object to be measured, wherein said measuring head has a contact measuring unit for measuring the inner diameter by contacting an inner surface of the object to be measured and an advancing/retreating unit for making said contact measuring unit to advance and to retreat in a radial direction and a scale unit, and wherein said circulation unit can rotate said measuring head around a center line of said inner diameter measuring device, wherein said advancing/retreating unit has a measuring unit holder which holds said contact measuring unit and is able to move integrally with said contact measuring unit in radial direction and wherein said scale unit comprises a scale sensor movable integrally with said measuring unit holder and a linear scale provided in parallel to moving direction of said contact measuring unit, wherein a measurement of the inner diameter is determined based on an amount of moving of said measuring unit holder in radial direction as detected by said scale sensor and on a detection result of said contact measuring unit.