PURPOSE: To detect the number of works held by a chuck and to pick up one by one works which are loosely loaded without human intervention, by detecting vibration of a chucking shaft.
CONSTITUTION: Because a detecting coil 18 is positioned between the magnetic body section 10 and the nonmagnetic body section 11 of a chucking shaft 9, the magnetic flux made by an attraction coil 20 changes as the chucking shaft 9 vibrates, and it creates in a detecting coil 18 induction electromotive force, which changes periodicaly. Because the cycle of this electromotive force is equal to that of the vibration of the chucking shaft 9, the number of attracted works 22 can be determined by measuring this cycle with a cycle meter 21. As the result of the determination, when one of the works 22 is attracted, the electric current across the coil 20 is continued to be energized and the work 22 is taken out. If two or more than two works are attracted, the electric current across the coil 20 is cut off and the work 22 is returned to loosely stacked works.
SAKATA CHIAKI
YAMADA SHIGERU
