Dynamic information storage or retrieval – Storage medium structure – Adjuncts or adapters
Reexamination Certificate
1995-05-01
2001-05-22
Klimowicz, William (Department: 2652)
Dynamic information storage or retrieval
Storage medium structure
Adjuncts or adapters
C360S133000, C206S308100
Reexamination Certificate
active
06236639
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to cartridges for disk-shaped storage media, and more particularly to partitions within such cartridges for enclosing the media in a compartment which protects it from external debris.
BACKGROUND OF THE INVENTION
Disk-shaped data storage media, such as magnetic diskettes and certain types of optical storage discs, e.g., magneto-optic disks, are typically protected by enclosures, or cartridges, which reduce contamination to the disk due to dust and debris. Such enclosures typically provide apertures covered by sliding shutters to allow access to the media by a disk drive.
As shown in
FIG. 1
, a disk-shaped storage medium
40
is usually protected by an upper cartridge shell
12
and a lower cartridge shell
14
which fit together to form a complete cartridge
10
. A drive may gain access to media
40
by sliding shutter
16
on cartridge
10
to an open position. Partitions are provided within the cartridge
10
to subdivide the enclosed space into various compartments. The partitions are typically formed by ribs which are provided on the interior surfaces of shells
12
and
14
. Typically, each rib has a height equal to about half of the distance between the interior surfaces of shells
12
and
14
when the cartridge
10
is assembled. The ribs are aligned so that they mate with each other to form compartments within cartridge
10
. Ribs
20
and
22
form a compartment
30
that separates medium
40
from compartments
18
.
As shown in
FIGS. 1 and 2
, a compartment
30
is a circular space bounded by interior surface
15
of lower cartridge shell
14
and the interior surface of upper cartridge shell
12
, and is within the circular boundary defined by ribs
20
and
22
. Compartment
30
may further include a rib
24
on interior surface
15
of lower cartridge shell
14
which defines a circular boundary concentric with rib
22
for supporting medium
40
in an outer circumferential area
42
of the medium which is not intended to store data. Compartment
30
may also include yet another rib
26
on interior surface
15
of lower cartridge shell
14
which defines a circular boundary concentric with rib
22
for supporting medium
40
in an inner circumferential area
46
of the medium which is not intended to store data.
Rib
22
defines the circumferential boundary of the lower portion of compartment
30
. The radius of the boundary is slightly greater than that of medium
40
.
A cross-sectional view of ribs
20
and
22
, taken along line
3
-
3
′ in
FIG. 1
, is shown as FIG.
3
. Rib
22
extends upward from interior surface
15
of lower cartridge shell
14
and rib
20
extends downward from interior surface
13
of upper cartridge shell
12
to form a smooth continuous wall when the upper and lower cartridge shells are assembled as cartridge
10
. Ribs
20
and
22
may be of a precisely determined height that allows them to contact at their tops at interface
38
, thereby forming continuous rib wall separating compartment
30
housing media
40
from compartments
18
. In the alternative, a small gap may be provided at interface
38
, as shown in FIG.
3
.
Rib walls which contact each other at their tops suffer, however, from the disadvantage of requiring very tight manufacturing tolerances, since the rib edge surfaces forming interface
38
must be in close proximity to each other, yet must have very limited interference to avoid causing a deformation of upper and lower cartridge shells
12
and
14
at locations
50
and
52
, respectively, which might result in unsightly bulges or cause cartridge
10
to malfunction. Alternatively, if a gap is provided between the two rib tops, debris particles may be able to migrate through the gap and onto medium
40
.
Drives for reading and/or writing data on disk-shaped optical storage media have error detection and correction codes (EDCC) incorporated in the drives' system electronics and firmware which allows for a potential loss of data bits by decoding them within the context of the retrievable data. However, should too many consecutive bits of data be lost due to a large debris particle or an accumulation of smaller debris particles, the EDCC system would be unable to decode the lost data. As new media products having increased storage density per unit area of media are developed, the newer media is increasingly sensitive to debris accumulation and smaller debris particles because of the closer spacing of the data bits.
An alternative prior art rib configuration is shown in cross-section in FIG.
4
. Rib
20
′ has a notch on one side of its top, causing the rib to be higher on one side than the other. Rib
22
′ is notched in a complementary fashion, so that the extended portion
62
of rib
20
′ mates with the shorter portion of rib
22
′, and the extended portion
64
of rib
22
′ mates with the shorter portion of rib
20
′. This overlapping design is less sensitive to manufacturing tolerances and thus allows for a relatively wide dimensional variation without causing noticeable deformation of the cartridge at locations
50
and
52
. This configuration also provides a gap that is more convoluted, thereby making it more difficult for debris particles to pass through the gap.
If cartridge
10
is to be formed by the injection molding of a thermoplastic material, it is desirable that ribs
20
′ and
22
′ be relatively thin, since ribs that are thicker than the wall from which they extend can cause defects, called sink marks, at locations
50
and
52
of the cartridge. However, due to the configuration shown in
FIG. 4
, ribs
20
and
22
must be even thinner at their top portions
62
and
64
, respectively. This makes the ribs difficult to fill during molding.
A second alternative prior art rib configuration is shown in FIG.
5
. Ribs
20
′ and
22
″ resemble ribs
20
′ and
22
′ of
FIG. 4
, but differ in that they have a more gradual transition between the shorter and longer portions,
62
′ and
64
′, respectively, of the ribs. This design suffers from some of the same disadvantages as the rib configuration of FIG.
4
.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a configuration for mating partition ribs which gives effective protection from media contamination by debris in the size range to which the particular media is susceptible, while at the same time providing a cartridge which can be easily produced by injection of a thermoplastic material by allowing easy and defect-free filling of the rib portions of the cartridge.
Accordingly, the present invention is directed to a cartridge for data storage media, e.g., disk-shaped recording media, having two cartridge shell halves, each of which has a rib on one surface thereof One rib has a groove in the top of the rib which extends along the length of the rib, while the other rib has a protrusion on the rib top which extends along the length of that rib. When the cartridge shells are assembled together, the two ribs are aligned so that the protrusion in one rib is aligned with and extends into the groove of the other rib. The tops of the two ribs define a gap between them. The gap entrance preferably has a nominal thickness of less than 0.2 mm, and more preferably about 0.1 mm. The ribs preferably have thicknesses of about 0.86 to 1.22 mm, measured radially.
The protrusion and groove are preferably of complementary shape. In one embodiment, the protrusion and groove are V-shaped and are provided along the centerlines of the ribs. The two ribs are aligned to form a rib wall which creates a compartment that separates the disk-shaped storage medium from the rest of the cartridge interior. This wall prevents debris such as dust particles from entering the media storage compartment.
REFERENCES:
patent: 4012011 (1977-03-01), Saito
patent: 4564878 (1986-01-01), Weavers et al.
patent: 4566653 (1986-01-01), Bettinger et al.
patent: 4894673 (1990-01-01), Beach
patent: 5199593 (1993-04-01), Ki
Fairchild John F.
Halberg Walter J.
Selg Donald W.
Turch Steven E.
Imation Corp.
Klimowicz William
Levinson Eric D.
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