Browse Prior Art Database

Rigid Disk Clamping System for Magnetic Disks

IP.com Disclosure Number: IPCOM000037024D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Bowen, AJ: AUTHOR [+3]

Abstract

Disclosed is a method for generating a low friction interface between a disk 2 and a cap 1 when clamping disks onto a spindle in a direct- access storage device (DASD) hard file product. In most DASD products, a number of rigid disks are stacked on a spindle and separated with cylindrical spacers. The combination of disks and spacers is stress-loaded by cap 1 screwed to a spindle. As cap 1 is screwed tight to the spindle, it comes in contact with disk 2. The interface between cap 1 and disk 2 is subject to friction as cap 1 is tightened, and plastic deformation of cap 1 begins. This deformation is balanced by deflection of disk 2 in the radial direction. This deflection results in radial curvatures of disk 2 which reduces file performance. The disclosed method minimizes this radial curvature on the surface of disk 2.

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Rigid Disk Clamping System for Magnetic Disks

Disclosed is a method for generating a low friction interface between a disk 2 and a cap 1 when clamping disks onto a spindle in a direct- access storage device (DASD) hard file product. In most DASD products, a number of rigid disks are stacked on a spindle and separated with cylindrical spacers. The combination of disks and spacers is stress-loaded by cap 1 screwed to a spindle. As cap 1 is screwed tight to the spindle, it comes in contact with disk 2. The interface between cap 1 and disk 2 is subject to friction as cap 1 is tightened, and plastic deformation of cap 1 begins. This deformation is balanced by deflection of disk 2 in the radial direction. This deflection results in radial curvatures of disk 2 which reduces file performance. The disclosed method minimizes this radial curvature on the surface of disk 2.

The sooner friction at the interface builds up, the greater the moment is for a given load force and, thus, the greater the disk deflection. By applying a low friction coating, like TEFLON* or electroless polished nickel, to the surface of cap 1, disk 2, or both, friction is reduced, resulting in a smaller deflection and in an improved file performance. Alternatively, a very thin interposer ring with low friction properties, such as MYLAR*, is placed at the interface, yielding the same results.

In the later end of the torque cycle, some moment is applied to disk 2 because plastic deformation must occur at...