Patent ID: 7278150

Claim:
A disc-chucking mechanism for fixing a ring-shaped disc, the disc-chucking mechanism comprising: a center shaft having a tapered recess, a hollow section, and a hole extending from the tapered recess to the hollow section, wherein the center shaft is adapted to support the disc; a piston provided in the hollow section; a rod attached to the piston, wherein the piston is operable to move the rod through the hole; a tapered cone having a tapered portion sized and shaped to fit in the tapered recess of the center shaft, wherein the rod extends through the hole and is attached to the tapered cone so that the piston can move the tapered cone; and an elastic O-ring having a variable diameter, wherein the O-ring is disposed between the tapered portion and the tapered recess, wherein, as the piston moves the tapered portion in a first direction, the tapered portion expands the diameter of the O-ring so that the O-ring presses the disc and fixes the disc, and wherein, as the piston moves the tapered portion in a second direction, the tapered portion moves relative to the O-ring such that the diameter of the O-ring contracts to move out of contact with the disc and releases the disc.