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Direct Access Storage Device Head Retraction Using Bias Force of Flex Cable

IP.com Disclosure Number: IPCOM000111060D
Original Publication Date: 1994-Feb-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Boutaghou, Z: AUTHOR [+2]

Abstract

A method to yield additional torque needed to unload the sliders in load/unload systems is described. The proposed solution positions the flex cable such that a net torque is biasing the actuator towards the load/unload ramp. The net torque is substantial and should be taken advantage of during parking of the slider.

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Direct Access Storage Device Head Retraction Using Bias Force of
Flex Cable

      A method to yield additional torque needed to unload the
sliders in load/unload systems is described.  The proposed solution
positions the flex cable such that a net torque is biasing the
actuator towards the load/unload ramp.  The net torque is substantial
and should be taken advantage of during parking of the slider.

      In load/unload devices, the spindle motor back-EMF, capacitive
storage devices, and battery storage devices are methods used to
unload the sliders from the recording surfaces onto the load/unload
ramp.  Most load/unload systems use the back-EMF from the spindle
motor to drive the actuator onto the ramp in case of power loss.  The
back-EMF voltage must be sufficient to generate enough force to
overcome the bearing stiction torque, the torque necessary to park
two sliders onto the ramp, and an additional bias torque.    Fig. 1
portrays an example of the required force at the the tip of the
slider versus several spindle motor torque constants for various
actuator designs to overcome bearing stiction forces and friction
forces from the sliders/ramp contact.  Low profile DASD have low
profile spindles incapable of producing enough back-EMF to park the
sliders onto the ramp.

Ka = Actuator torque constant
 Kem = Motor torque constant
 1 Slider refers to parking 1 slider
 2 Sliders refers to parking 2 sliders

      Furthermore, Fig. 2 shows the decay of th...