JPS643866A - Internal edge chuck mechanism for disk - Google Patents

Abstract

PURPOSE:To prevent the burnishing process operation for the periphery of a center hole from being disturbed by engaging a clamp part which has a couple of claw parts at its outer periphery, which is not larger in thickness than a disk, and which expands and contracts radially with the beveled parts of both edges of the center hole of the disk. CONSTITUTION:One surface of the discoid clamp part 15 is integrated to a cylindrical part 19 and has a radial slit 20. When the disk 4 is positioned at the outer periphery and a positioning piston part 22 is moved forth while the piston part 22 is moved to reduce the external diameter of the clamp part 15, the clamp part 15 is pressed and expanded at the time of passing through the slanting surface 19a of the cylindrical part, and the claw parts 16 and 17 engage the internal edge slanting surfaces 4b and 4c of the disk 4 to chuck the disk 4. When the piston part 22 is moved back, the clamp part is contracted and the disk can be detached. The disk is therefore clamped by the expansion and contraction of the clamp part and the thickness of the clamp part is made smaller than or equal to that of the disk, which can be processed from both surfaces nearly to the center hole, and a chuck mechanism is prevented from disturbing the burnishing process.