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Continual Flexing of Flexible Disc Stack for Deflection Force Reduction

IP.com Disclosure Number: IPCOM000081568D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Weidenhammer, JA: AUTHOR

Abstract

Laminated disc pack 1 contains a large number (e.g., 300) of thin flexible discs (e.g., oxide coated MYLAR*; 0.0017'' thickness; 12'' diameters) corotating at high speed (e.g., 1800 rpm) on shaft 2. The pack is accessed for recording/reproduction by insertion of splitter blade 3 at randomly selected interfaces.

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Continual Flexing of Flexible Disc Stack for Deflection Force Reduction

Laminated disc pack 1 contains a large number (e.g., 300) of thin flexible discs (e.g., oxide coated MYLAR*; 0.0017'' thickness; 12'' diameters) corotating at high speed (e.g., 1800 rpm) on shaft 2. The pack is accessed for recording/reproduction by insertion of splitter blade 3 at randomly selected interfaces.

When the blade is disengaged from the pack 1, centrifugal force removes air from between the disc layers so that the discs tend to squeeze tightly together. The resulting static friction operates to lock the discs 1 together making the assembly stiff and resistant to deflection by the blade 3. This tends to increase the wear stress on the disc surfaces due to blade operation. This condition can be alleviated by rotating the undeflected (undisturbed) discs 1 in a permanently bent mode.

As indicated in the drawing, stabilizer plate 4, arranged at an acute angle (20- 30 degrees) to the normal path of rotation 5, introduces a bend in the rotational orbit of the undisturbed discs. By locating plate 4 at a suitable position relative to the path of operation of blade 3, a hydrodynamic air film is established between the plate 4 and the undisturbed discs 1 which is not affected by operation of the blade 3. This bend allows blade operations to be carried out with reduced force. * Trademark of E. I. du Pont de Nemours & Co.

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