PURPOSE: To easily achieve high efficiency of removal work of a grinding wheel and to enable effective response to a grinding wheel with small outer diameter without deteriorating rigidity of the grinding wheel.
CONSTITUTION: A removal assisting device are provided with a cover member 88 which can be drawn in the axial direction of a rotating shaft 52, a shaft body 98 for rotating the cover member 88 around the axis crossing the axial direction and a locking means 124 which is fitted removably in an engagement hole 114 provided at the cover member 88. The locking means 124 is provided with an oscillating lock piece 142 which is interlocked with an action of this locking means 124 engaging with the engagement hole 114 and is engaged with one of groove parts 74a to 74c formed at a boss part 66 of a grinding wheel 52 so that this grinding wheel can be held.
Tatsuya Takeuchi
Ujibashi Koji
