PURPOSE: To stop the rotation of a rotary shaft when the vibration of its jutting portion has exceeded a limit vaue, by providing an accelerometer in the jutting portion coaxially to the shaft to always detect the vibration.
CONSTITUTION: An accelerometer 14 is provided in the jutting portion of a mandrel shaft 1 coaxially thereto. The signal takeout wires 15 of the accelerometer 14 are led out through the axial thin hole of the haft 1, a rotary cylinder 9 for the shaft and a slip ring 16. The acceleration signal of the accelerometer 14 is processed through a low-pass filter 17 for passing vibration frequencies not higher than the primary bending natural frequency of the mandrel shaft without a strip, so that the signal is removed of high frequencies of impulse or the like. The magnitude of the acceleration indicated by the signal passed through the filter 17 is compared with that of the signal of a limit level signal generator 19 by a level comparator 18. When the magnitude of the acceleration has exceeded a limit level, an alarm 20 is indicated and the rotation of the mandrel shaft 1 is stopped.
NARAKI YASUSHI
ITANI HIKOTAROU
KATAYAMA KEIICHI
TASHIRO KATSUZOU
YAMAMOTO MICHINORI
