Patent ID: 7360227

Claim:
A chucking apparatus which coaxially holds a removable recording disk through a central through hole thereof and which is mounted on a rotor to rotates about a rotational axis, the rotor having a shaft, the chucking apparatus comprising: a centering case which is located at a rotational symmetrical location around the rotational axis and which has a radially outer peripheral surface on which the recording disc is to be mounted radially facing an inner periphery of the through hole of the recording disk, the centering case having an inner cylindrical portion which the centering case is fixed to an outer surface of the shaft; a recording disk mounting surface fixedly located on the rotor member on which the recording disk is placed; a plurality of chuck pawls arranged in a radial direction on the centering case, each of chuck pawls located symmetrically about the rotational axis; and a resilient member which is disposed radially inward of the chuck pawl and which biases the chuck pawl radially outward, each of the chuck pawls comprising: a base which is accommodated in the centering case and which receives a biasing force from the resilient member, and a tip end which projects from the radially outer peripheral surface of the centering case radially outward, and which holds the recording disk, wherein the tip end includes: a first inclined surface defined as an upper side of the tip end, and contacted by a lower side of a peripheral edge of the through hole of the recording disk when the recording disk is pushed down to be set on the chucking apparatus, a second inclined surface defined as an outer part on a lower side of the tip end, and contacted by an upper side of the peripheral edge of the through hole of the recording after the recording disk was pushed down; a curved surface defined from an outer portion of the base to an inner potion of the second inclined surface; and a boundary defined between the curved surface and the second inclined surface formed in a form of a stepped recess; wherein an angle formed between the second inclined surface in the contacting portion with the recording disk and the upper surface of the recording disk is smaller than an angle formed between the upper surface of the recording disk and a phantom curved surface connecting the curved surface and an outermost diameter portion of the tip end.