Patent ID: 7856642

Claim:
A chucking mechanism operable to detachably mount thereon a disk including an upper disk base, a lower disk base pasted with the upper disk base and a central opening portion, and rotate the disk in a concentric manner with a predetermined rotary axis, the chucking mechanism comprising: a center case arranged above a turn table, including a cylindrical portion which fits the central opening portion of the disk and a top plate covering an upper end of the cylindrical portion; an elastic member arranged radially inside the cylindrical portion; and a plurality of claw members receiving a radial force from the elastic member, radially projecting from the cylindrical portion, and supporting the central opening portion, each of the claw members comprising: a sliding surface; and a disk retaining surface separate from the sliding surface, the disk retaining surface being provided with a tip portion at a radially outmost area of each of the claw members; the sliding surface determining an axially lowest point of the tip portion, a first face extending from the sliding surface being below the tip portion; wherein the turn table includes a disk mounting portion on which the disk is mounted, wherein the tip portion moves, when the disk makes contact with the chucking mechanism, axially downwardly and radially inwardly, and wherein the tip portion is axially above a bottom surface of the upper disk base when the disk is mounted on the disk mounting portion, wherein an axial distance between the tip portion and a top surface of the disk mounting portion is, when the tip portion is at the axially lowest point, greater than at least approximately 1.08 mm.