Apparatus for installing a disk

Claim 1

In an apparatus for installing a disk having a through hole formed in the center thereof of the type having a disk support having a supporting surface for supporting one side of the disk; a rotatable shaft having one end fixed to said disk support and having the other end disposed above said support surface; and a disk holder for pressing the disk on its other side toward the supporting surface, thereby causing the disk to be fixed between the disk holder and the disk support, the improvement comprising said disk holder being detachably fitted to the rotatable shaft, and including: a holder body defining a hole into which said rotatable shaft is inserted to permit movement of said holder body along the rotatable shaft; pressure means disposed on the holder body to elastically press the disk on its other side against the supporting surface; and slip preventive means for preventing the holder body from slipping off the rotatable shaft by engaging the holder body with the rotatable shaft, said slip preventive means including (i) an engaging groove formed on the outer periphery of said other end of the rotatable shaft; (ii) at least one engaging lever, one end of which is engageable with said engaging groove and the other end of which protrudes outwardly from the holder body when the disk holder receives the rotatable shaft in its hole and is pushed against the disk disposed on the disk support, said at least one engaging lever being pivotally mounted on the holder body in the middle part thereof so as to be pivotable between a first position wherein said one end thereof is engaged with the engaging groove while the other end thereof protrudes outwardly from the holder body and a second position wherein said one end thereof is disengaged from the engaging groove while the other end thereof is pressed into the holder body; and (iii) biasing means operatively connected to said at least one engaging lever to bias said at least one engaging lever in a direction towards said first position and wherein said holder body defines a cavity, said pressing means including a pressure assembly disposed in said cavity of the holder body to permit movement of said pressure assembly in said cavity, said pressure assembly defining a pressing surface which is pressed against the other side of the disk; and urging means disposed between the holder body and the pressing assembly to urge the pressing surface of the pressure assembly toward the supporting surface.