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A Bistable, Zero Steady-State Power, Rotary-Actuator Lock for DASD

IP.com Disclosure Number: IPCOM000104044D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 4 page(s) / 114K

Publishing Venue

IBM

Related People

Sri-Jayantha, M: AUTHOR [+2]

Abstract

Disclosed is a design of a DASD actuator lock that utilizes a bistable mechanism such that power is required only to switch it from the locked to the unlocked state and vice versa. A hook mechanism is used to provide reliable locking even under very high shock conditions.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

A Bistable, Zero Steady-State Power, Rotary-Actuator Lock for DASD

      Disclosed is a design of a DASD actuator lock that utilizes a
bistable mechanism such that power is required only to switch it from
the locked to the unlocked state and vice versa.  A hook mechanism is
used to provide reliable locking even under very high shock
conditions.

      An actuator lock is a device that is used to hold the slider
assembly over a specific region of the disk during powered-down and
powered-off conditions.  The region of the disk so designated is
usually the landing zone so that, in the case of an external shock to
the system, damage to the disk can be minimized.

      The use of DASDs in battery operated portable and laptop
computers has seen their exposure to shock greatly increased.  In
addition, the need to increase battery life has made the minimization
of power very important.  Actuator locks now need to provide stronger
locking mechanisms with a minimal consumption of power.

      The locks currently in use do not provide both conditions
simultaneously.  One type has a magnetic latch to hold the actuator
at its rest position.  The actuator is unlocked by applying a
suitable force via it's voice coil motor to break loose from the
stop.  This lock has a limited holding force.  The other type is one
where a lever hooks onto the actuator at its rest position.  Such a
lock is capable of withstanding very high shocks without releasing
the actuator.  The actuator is unlocked via a solenoid that attracts
the lever away from it.  The solenoid needs to be continuously
energized and so consumes a lot of power.

      This article presents the design of a lock that can provide the
positive locking needed to protect against very high shock conditions
and which has a bistable operating mode such that it consumes no
power other than to switch from one state to the other.  The lock has
been designed for small rotary actuator DASD but in principal could
be used for locks for larger systems and for DASDs using linear
actuators.

      Fig. 1 shows a top-view schematic of the lock as incorporated
in a small disk file that has a rotary actuator.  The lock assembly
is highlighted by an arrow.  It is shown here as being integral with
the voice-coil-motor (VCM) actuator.  Alternatively it could have
been made as a separate assembly and positioned adjacent to the...