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Absorbent Metal Crash Stop Against Rebound Disclosure Number: IPCOM000014871D
Original Publication Date: 2000-Jul-01
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 93K

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Absorbent Metal Crash Stop Against Rebound


Absorbent Metal Crash Stop against Rebound

M. Ohta
J. Hatazawa
K. Kuroki
K. Takahashi

     This article describes an absorbent metal crash stop for load/unload
type Hard Disk Drive (HDD). In case of a super small HDD such that back-emf
of spindle motor is too low to retract actuator, discharge current of cpacitor
is applied to Voice Coil Motor (VCM) at power off. A good safety margin
discharge current is required so that actuator must be retracted at any time.
Therefore, very occasionally actuator hits the outer crash stop and bounces
back to the disk. In this case, spindle motor cannot be rotated again because
head of actuator is stuck on the disk strongly.

     The outer crash stop made of magnetic body helps actuator rebound. This
magnetic body crash stop is pulled by VCM leakage flux ([Fig.1 detail-A).
This magnetic force and the friction absorb the retract impact. After
absorbing enerby, the crash stop is back to original posision by magnetic


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Ram p

Pow er off retract by capacitor discharge


Pulled by V C M leakage flux




m agnetic body outer crash stop

Sw ay to absorb retract energy

Fixed pin

Detail-A (original position)


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