Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
2000-03-17
2002-10-15
Davis, David (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
C369S291100
Reexamination Certificate
active
06466406
ABSTRACT:
FILED OF THE INVENTION
The present invention relates generally to data-storage cartridges for storing digital information. More particularly, the invention relates to a data-storage cartridge having surface recesses formed therein to enhance the circulation of air within the cartridge.
BACKGROUND OF THE INVENTION
FIG. 1
is a cross-sectional illustration of a conventional data-storage cartridge
100
. The data-storage cartridge
100
comprises an outer shell
101
having an upper half
102
and a lower half
103
. The data-storage cartridge
100
also includes a circular data-storage medium
104
. The data-storage medium
104
is rotatably disposed within the outer shell
101
. The data-storage medium has an upper recording surface
104
a
, a lower surface recording
104
b
, and an outer edge
104
c
. The data-storage medium
104
also includes a centrally-disposed hub
106
. The hub
106
includes an upper surface
106
a
and a lower surface
106
b
. A fabric liner
110
is disposed on an inner surface
102
a
of the outer shell upper half
102
. A fabric liner
111
is likewise disposed on an inner surface
103
a
of the outer shell lower half
103
.
The lower half
103
of the outer shell
101
includes a hub access opening
107
. A portion of the hub
106
is rotatably disposed within the hub access opening
107
. The hub
106
and the hub access opening
107
are sized so that a gap
108
exists between the hub
106
and the hub access opening
107
. This arrangement allows the hub
106
to freely rotate within the hub access opening
107
. The hub
106
is adapted to engage a spindle of a disk drive (not shown) when the data-storage cartridge
100
is inserted into the disk drive. The spindle is coupled to a spindle motor within the disk drive. The spindle motor rotates the data-storage medium
104
via the spindle and the hub
106
.
The outer shell
101
also includes a head access opening
109
. The head access opening
109
permits the read/write heads of the disk drive to access to the data-storage medium
104
. A spring-loaded shutter (not shown) covers the head access opening
109
when the data-storage cartridge
100
is not inserted in the disk drive.
The rotational motion of the data-storage medium
104
induces various airflow patterns within the data-storage cartridge
100
. In particular, the air in contact with the rotating data-storage medium
104
flows radially outward, i.e., toward the outer edge
104
c
of the medium
104
. This airflow is induced by the combined effect of the rotational motion of the data-storage medium
104
and viscous forces between the medium
104
and the surrounding air. (The airflow patterns within the data-storage cartridge
100
are represented by various arrows
112
shown throughout
FIG. 1.
)
The outward displacement of air along the lower surface
104
b
of the data-storage medium
104
causes air to be drawn into the data-storage cartridge
100
through the gap
108
(see the arrows
112
). Hence, the air that is outwardly displaced along the lower surface
104
b
is replaced by air drawn through the gap
108
. A substantial portion of the outwardly-displaced air eventually exits the data-storage cartridge
100
by way of the head access opening
109
after reaching the outer edge
104
c
of the data-storage medium
104
.
The upper half
102
of the outer shell
101
, by contrast, does not include any openings that allow a substantial volume of ambient air to enter the data-storage cartridge
100
. The lack of such openings, in conjunction with the outward displacement of air along the upper surface
104
a
of the data-storage medium
104
, causes a pressure differential to develop between the top and the bottom of the data-storage medium
104
. In particular, the aerodynamic pressure above the upper surfaces
104
a
and
106
a
decreases in relation to the aerodynamic pressure below the lower surfaces
104
b
and
106
b
. The resulting pressure differential across the medium
104
is greatest proximate the hub
106
, and decreases with increasing radial distance from the hub
106
. The pressure differential is related to the rotational velocity of the data-storage medium
104
. Specifically, higher rotational velocities increase the magnitude of the pressure differential.
The pressure differential across the data-storage medium
104
can produce a number of undesirable effects. For example, the pressure differential tends to lift the data-storage medium
104
upward, i.e., in the z
+
direction (the z
+
direction is denoted on a coordinate system
8
shown in FIG.
1
). This upward displacement can result in inadvertent contact between the medium upper surface
104
a
and a flying read/write head positioned proximate the upper surface
104
a
during data storage and retrieval operations. Furthermore, the upward displacement of the medium
104
can increase the mechanical loading of a non-flying read/write head beyond acceptable levels. Inadvertent head-medium contact and high mechanical loading can result in damage and premature wear of the read/write head and the data-storage medium
104
. These factors can also lead to a loss of data from the data-storage medium
104
.
In addition, the vertical displacement of the data-storage medium
104
can make it difficult to load the read/write head onto the data-storage medium
104
. In particular, substantial vertical displacement of the data-storage medium
104
can cause the read/write head and its supporting structure to contact the data-storage medium
104
as the read/write head is moved from its parked position beside the medium
104
. Such contact can damage the data-storage medium
104
, the read/write head, and the supporting structure of the read/write head. Furthermore, the need to account for the vertical displacement of the data-storage medium
104
may cause the height (z dimension) of the data-storage cartridge
104
to be greater than would otherwise be required. The need to account for this displacement can also cause the height of the disk drive in which the cartridge
104
is utilized to be greater than would otherwise be required.
In addition, low rates of airflow over the upper surface
104
a
of the medium
104
can result in oscillations in the medium
104
. More particularly, low airflow rates across the surface
104
a
exert minimal aerodynamic damping on the data-storage medium
104
. Minimal damping increases the potential for the data-storage medium
104
to oscillate. Oscillation of the medium
104
can result in the problems and disadvantages described above in connection with the vertical displacement of the data-storage medium
104
. Furthermore, low rates of airflow over the upper surface
104
a
may cause a read/write head positioned above the upper surface
104
a
to operate at unacceptably high temperatures.
The above discussion illustrates the existing need for a data-storage cartridge having a data-storage medium that operates with a minimal aerodynamic pressure differential across its upper and lower surfaces. Optimally, the cartridge should operate with sufficient airflow across its upper surface to inhibit substantial oscillation of the medium, and to adequately cool a read/write head positioned above the upper surface. The present invention is directed to these and other objects.
SUMMARY OF THE INVENTION
In accordance with the above-noted objects, a presently-preferred embodiment of the invention comprises a data-storage cartridge having an outer shell. The outer shell includes an upper half having an inner surface. A recess is formed in the inner surface. The recess extends between a first position proximate an outer periphery of the inner surface and a second position proximate a center of the inner surface. The outer shell also includes a lower half. A hub access opening is formed in the lower half of the outer shell. The hub access opening is substantially aligned with the center of the inner surface.
The data-storage cartridge also comprises a data-storage medium. The data-storage medium has a centrally-disposed hub and
Davis David
Iomega Corporation
Woodcock & Washburn LLP
LandOfFree
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