| 摘要 |
A chuck adapted for releasably securing data discs and the like for processing and testing procedures includes an arbor secured at its proximal end to a rotatable tool, and a cylindrical bore within the arbor houses a reciprocating piston. A spring within the bore biases the piston proximally, and a piston rod extends through an aperture in the distal end of the arbor. The distal end of the arbor includes a neck portion extending axially and distally and dimensioned to extend through the central aperture of a data disc, and an annular land surface extending about the neck portion to impinge upon the disc surface adjacent to the central aperture thereof. A resilient bushing is secured coaxially to the distal end of the piston rod, the bushing having a truncated conical configuration tapering toward the distal end. The proximal end of the bushing is dimensioned to be slightly smaller in diameter than the inner diameter of the annular land surface, and is provided with a bevelled outer edge. Air pressure is provided to the proximal side of the piston to drive the piston and piston rod distally, the bevelled edge of the bushing impinging on the end surface of the neck portion of the arbor when the piston is extended distally. When the air pressure is relieved and a disc has been secured about the neck portion of the arbor, the spring force of the spring within the arbor drives the piston and rod proximally, compressing the bushing axially and causing it to deform and spread at its proximal end. The bevelled proximal edge of the deforming bushing wipes radially outwardly onto the inner annular surface of the disc, urging the disc to impinge on the annular land surface of the arbor and securing the disc thereto. The bevelled edge is significant in creating a trailing edge effect which pushes a disc onto the land surface, even if the disc was not originally placed correctly on the land surface.
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