Section 3
Principles
of
Operation
3.1.6
AUTOMATIC ACTUATOR LOCK
The ProDri,'e uses a dedicated landing zone to ensure data integrity and prevent damage during shipment.
It also uses AIRLOCK@. Quantum's patented means
of
locking the headstack in the landing zone. The
AIRLOCK consists
of
an airvane mounted close to the edge
of
the disk stack with an
ann
that intersects the
actuator to hold the headstack in the landing zone whenever the disk is not rotating. As DC power is
applied to the motor and the disk stack starts rotating, an airflow is generated around the disk. As airflow
increases with disk rotation, the airvane and its
ann
rotate. enabling the headstack to move freely out
of
the
landing zone. When DC power is removed from the motor, an electronic return mechanism automatically
pulls the actuator into the landing zone so the
AIRLOCK can hold it
in
place.
3.1.7
AIR FILTRATION
The
ProDri~e
Series drives are Winchester type drives and. as such, the heads fly very close to'the media
surface.
The
nominal flying height is 8 microinches - more than 2500 times smaller than the period
at
the
end
of
this sentence.
It is absolutely essential that the air circulating within the drive
be kept free
of
particles.
To
this end, the
drive is assembled in a Class 100 purified air environment, then sealed with a metal cover. During the life
of
the drive. the rotating disks act as an air pump to force the air through an internal filter. Figure 3-2
shows the air flow in the enclosed area
of
the drive.
The lowest pressure area within the drive is at the top in the center
of
the spindle. A 0.3 micron breather
filter is bonded in this area
of
the cover. This filter allows outside air into the sealed area
of
the drive to
equalize internal and external pressures. The highest pressure area within the drive is located at the outer
edge
of
the disk. Another 0.3 micron filter called the circulation filter is mounted to the base casting at
this location. Air is pumped continuously into the side
of
the filter facing the rotating direction
of
the
disks, is filtered, and exits from the side
of
the filter facing away from the rotating direction
of
the disks.
Since this area
of
the drive is at a lower pressure than at the edge
of
the disks, air will circulate through the
filter. This setup ensures a continuous flow
of
filtered air as soon as the disks start to rotate. Due to the
stringent cleanliness required, the cover and seals should not
be tampered with.
FIGURE
3·2
Air
Filtration
3
MICRON
CIRCULATION
FILTER
Principles
of
Operation 3 • 3
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