Patent ID: 7389571

Claim:
A retaining ring attaching device for attaching a retaining ring having an opening to a shaft, comprising: chucking arms configured to expand the retaining ring, put the retaining ring on the shaft and contract the retaining ring; a chucking arm moving mechanism configured to move the chuck arms holding the retaining ring so as to move the retaining ring in a first direction in which a gap in the retaining ring moves away from the shaft while the retaining ring is contracting on the shaft, wherein the chucking arm moving mechanism includes: sliders capable of sliding in a second direction in which the retaining ring expands; and a guide mechanism capable of sliding the chucking arms in a third direction inclined to the second direction toward the first direction so that the chucking arms move toward each other, pushing the retaining ring in the first direction; a motor having a rotating shaft; an eccentric cam having an inner eccentric cam and an outer eccentric cam, and fixedly mounted on the rotating shaft of the motor; and cam followers connected to the sliders so as to move along the inner eccentric cam or the outer eccentric cam to slide the sliders.