Patent attributes
An inner diameter measuring device comprises an object to be measured supporting carriage, being arranged movably along a rail installed on an upper surface of a bed and used for holding a hollow pipe to be measured, a supporting shaft extended from a base end to a forward end of the bed, being insertable into the pipe to be measured and being cantilever-supported, and an inner diameter measuring unit installed on a forward end of the supporting shaft, being insertable into the pipe to be measured and for measuring the inner surface of the pipe to be measured. The inner diameter measuring unit is adapted to be inserted into the pipe to be measured, and is adapted to measure an inner diameter of the pipe to be measured in a process where the object to be measured supporting carriage is moved toward the base end of the supporting shaft.