To detect a blade from being displaced promptly with no errors by forming an eddy current sensor with high oscillating frequency and an eddy current sensor with low oscillating frequency so as to revolve near an inner periphery cutting edge on the back side of a blade and on the center line in the cut direction of a work depending upon the difference in the specific resistance of the work.
A sensor revolving plate 14 is provided with the first and second blade displacement detecting sensors consisting of an eddy current sensor at a prescribed angle to the revolving center respectively. The first blade displacement detecting sensor 9a, whose oscillating frequency is high, is used for a work with high specific resistance. The second blade displacement detecting sensor, whose oscillating frequency is low, is used for a work with low specific resistance. The work 7 is set to face the inside of the opening 4 of a blade 3. An engagement shaft is moved to the central part of a stroke, and the first and second blade displacement detecting sensors are positioned out of a moving area at the time of cutting a slice piece for the initial cutting.
NISHIYORI TOMOYUKI
HAMAZAKI TATSUMI
