SCREW-HOLE MEASURING APPARATUS

PURPOSE:To make it possible to measure the depth of a screw hole and the like in a machining line without manual working. CONSTITUTION:Light is projected on the surface of the thread ridge of a screw hole 22 from the tip part of an optical fiber sensor 10 at an approximately orthogonally intersecting angle. Then, the reflected light corresponding to the shape (presence or absence of a thread and the like) of the screw hole 22 is obtained. During the movement of the optical fiber sensor, the electric signal indicating the amount of the received reflected light is compared with the threshold value which is set in correspondence with each specified position of the screw hole 22 beforehand. Thus, the arriving position of the tip part of the optical fiber sensor 10 is detected. In this way, the depths of the screw hole and a hole before threading are measured.