PURPOSE: To enable a position of an attracting portion to be changed correspondingly to the shape and working portion of a workpiece without limiting the working portion by providing movably and fixedly a plurality of vacuum adsorbing portions for holding the workpiece in a chuck body.
CONSTITUTION: A chuck body 11 is formed radially with dovetail grooves 14. vacuum attracting portions 12aW12d are fromed on the respective under surfaces with projections to be inserted into the dovetail grooves 14 respectively which guide the athracting portion 12aW12d. A lock screw is vertically threaded into the dovetail 14 to abut against the projection on the under surface of the vacuum attracting portions 12aW12d and fix said portions 12aW12d to the chuck body 11. The vacuum attracting portions 12aW12d are located correspondingly to the shape of a workpiece 24 and the working portion of a tool 25 to hold the workpiece 24. The vacuum attracting portions 12aW12d may be replaced by electromagnetic attracting portions if necessary.
KANAMARU TOSHIMI
SHIGA TOMOYA
IKEGAMI KENZOU
