SHAPE DETECTING APPARATUS

PURPOSE:To effect stabilized shape detection of a surface of plate, by mounting a hollow multi-division rotor of nonmagnetic material provided with heat-resisting property so that a gap is maintanined by air injection between shaft and outerperiphery of the shaft. CONSTITUTION:On a hollow fixed shaft 1 a hollow multi-division rotor of heat- resistant and nonmagnetic material is mounted free to rotate in such a way that the required gap is maintained between the shaft and the outer periphery of the shaft 1. A number of injection holes 4 are perforated along the peripheral direction of the shaft 1 and air introduced under pressure to the inside of the shaft 1 is made to blow out from each holes 4 to form an air bearing with the aid of a cap 2 and a good conductive layer 5 is constructed on the inner surface of each rotor 3. Further, an eddy current system displacement-meters 6, 6 utilizing impedance changes are fixed on top and bottom position of the shaft 1 and wires connected with these meters 6, 6 are led to a computer 8 and then to a display apparatus 9.