Browse Prior Art Database

Normally Closed Inertia Latch for a Disk Drive Rotary Actuator

IP.com Disclosure Number: IPCOM000115792D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Albrecht, D: AUTHOR [+2]

Abstract

An inertia latch system for a disk drive rotary actuator is disclosed that is normally closed (latched position) such that when a rotational shock input is applied to the drive, an additional latching force proportional to the applied rotational acceleration provides an instantaneous additional latching or holding force. Thus when the drive is not in use, the actuator is prevented from moving from the "parked" position into the data band where the head sliders could cause physical damage that would result in loss of data. In the past, other latching techniques have included devices such as costly and unreliable active solenoids, low force permanent magnet latches, and normally open inertia latches.

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Normally Closed Inertia Latch for a Disk Drive Rotary Actuator

      An inertia latch system for a disk drive rotary actuator is
disclosed that is normally closed (latched position) such that when a
rotational shock input is applied to the drive, an additional
latching force proportional to the applied rotational acceleration
provides an instantaneous additional latching or holding force.  Thus
when the drive is not in use, the actuator is prevented from moving
from the "parked" position into the data band where the head sliders
could cause physical damage that would result in loss of data.  In
the past, other latching techniques have included devices such as
costly and unreliable active solenoids, low force permanent magnet
latches, and normally open inertia latches.  In the latter case, when
an external rotational shock is applied, the inertia device must
rotate into the latch position before the actuator can rotate out of
the park zone.  This requires that the parking zone be wide enough to
accommodate this displacement which in turn adversely affects the
amount of available data storage area.

      The disclosed inertia latch system is shown in the latched
position in Fig. 1A and the unlatched position in Fig. 1B.  In the
normally closed position, the latching lever bias force is generated
by the magnetic attraction between the lever or a magnetic member on
the lever and the Voice Coil Magnet (VCM).  The latching surfaces on
the inertia mass and actuator...