Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
1998-08-11
2001-10-02
Ometz, David L. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
C360S099050, C369S270100
Reexamination Certificate
active
06297931
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a signal recording medium and a disc cartridge holding this signal recording medium.
2. Description of Related Art
Up to now, a signal recording medium, having the major surface of a flexible disc substrate as a signal recording surface and adapted for recording information signals on this signal recording surface, such as a magnetic disc, has been in use.
As a magnetic disc employing a flexible disc substrate, such a disc having the diameter of 3.5 inch is in use. This magnetic disc has a center hub for chucking the magnetic disc to a disc drive device. The magnetic disc, used so extensively, has a recording capacity of 2 megabyte (MB).
The magnetic disc
200
, now in wide use, has a disc substrate
201
of a flexible synthetic resin material, with the major surface of the disc substrate being used as a signal recording surface, as shown in
FIGS. 1 and 2
. The disc substrate
201
has a circular center opening
201
a
which is closed by a hub
202
.
This hub
202
is formed of a magnetic material, such as iron, and has a tubular projection
202
a
fitted in the center opening
201
a
, and is mounted on the disc substrate
201
by having a flange
202
b
on the outer rim side of the projection
202
a
bonded to the rim of the center opening
201
a
, as shown in FIG.
2
. At the center of the hub
202
is formed a rectangular spindle opening
202
b
passed through by a spindle
221
of a rotation driving unit
220
provided on the disc drive device as shown in FIG.
3
. At a position of the hub
202
offset from a driving pin
223
on the disc drive device is bored a rectangular driving pin engagement opening
202
c
engaged by a driving pin
223
on the disc drive device. That is, the driving pin engagement opening
202
c
is formed at a pre-set distance from the spindle opening
202
b.
The spindle opening
202
b
, provided in the hub
202
, substantially has the shape of a square each side being sized to be slightly larger than the diameter of the spindle passed therein. This spindle opening
202
b
has its center C
1
—C
1
offset towards the driving pin engagement opening
202
c
with respect to the center O
2
—O
2
of the hub
202
, as shown in FIG.
2
. The spindle opening
202
b
is formed in the course of drawing the magnetic material of the hub
202
and has an upstanding wall section
202
f
on each side, as shown in FIG.
2
. These upstanding wall sections
202
f
support the peripheral surface of the spindle
221
passed through the spindle opening
202
b
and functions to permit the spindle
221
to pass through the spindle opening
202
b
. The corners of the substantially square-shaped spindle opening
202
b
are arcuately formed, as shown in FIG.
1
.
The hub
202
, mounted on the disc substrate
201
, has the distal end face of the projection
202
a
, in which are formed the spindle opening
202
b
and the driving pin engagement opening
202
c
, as a setting surface
202
e
for a disc supporting surface
222
a
of a disc table
222
of the disc rotation unit
220
. The outer rim side of the setting surface
202
e
is used as a suction portion by a magnet
224
arranged on the outer rim side of the disc supporting surface
222
a.
The magnetic disc
200
, arranged as described above, is rotated in unison with the disc table
222
of the disc rotation unit
220
provided on the disc drive device side, as the hub
202
is checked and centered with respect to the disc table
222
. The information signals are recorded or reproduced for the magnetic disc
200
by the magnetic disc
200
being operated by a magnetic head.
The disc rotation unit
220
, provided on the disc drive device, on which is loaded the magnetic disc
200
, has the disc table
222
integrally mounted on the distal end of the spindle
221
run in rotation by a spindle motor, not shown, as shown in FIG.
3
. The upper surface of the disc table
222
mounted on the distal end of the spindle
221
is a disc supporting surface
222
a
on which is set the hub
202
of the magnetic disc
200
. On the disc table
222
is mounted a driving pin
223
at a position offset from the spindle
221
. The driving pin
223
is mounted for movement in a direction emerging from or receding into the disc supporting surface
222
a
and in a direction towards and away from the disc supporting surface
222
a
. The driving pin
223
is biased by biasing means, not shown, in a direction away from the spindle
221
.
On the disc supporting surface
222
a
of the disc table
222
is arranged a ring-shaped magnet
224
, such as a rubber magnet, arranged for surrounding the disc supporting surface
222
a
. The magnet
224
is mounted on the disc table
222
so that the magnet is lower in level than the disc supporting surface
222
a
on which is set the hub
202
of the magnetic disc
200
so that a pre-set distance H
0
is maintained between the magnet surface and the setting surface
202
e
of the hub
202
set on the disc supporting surface
222
a.
The magnetic disc
200
is chucked on the disc table
222
by having the spindle
221
passed through the spindle opening
202
b
, engaging the driving pin
223
in the driving pin engagement opening
202
c
, setting the setting surface
202
e
on the disc supporting surface
222
a
of the disc table
222
, as shown in FIG.
4
and by having the hub
202
attracted by the magnet
224
.
The state in which the magnetic disc
200
is loaded on the disc table
222
is hereinafter explained.
In an initial state in which the magnetic disc
200
is set on the disc table
222
and the spindle
221
is passed through the spindle opening
202
b
with the driving pin
223
engaging in the driving pin engagement opening
202
c
, the spindle
221
and the driving pin
223
are usually inserted into or engaged with the spindle opening
202
b
and the driving pin engagement opening
202
c
without being thrust from the inner peripheral surface of the spindle opening
202
b
or the driving pin engagement opening
202
c
. At this time, the center-to-center distance F between the spindle
221
and the driving pin
223
is an initial state distance for which the driving pin
223
is not moved towards the outer rim of the magnetic disc
200
.
The spindle opening
202
b
is formed as a square-shaped opening having the length of each side equal to L and having arcuately rounded corners, as shown in FIG.
5
. The spindle
221
, inserted into the spindle opening
202
b
, is formed as a column having a diameter &phgr;E shorter than the length D of one each side of the spindle opening
202
b
. The driving pin engagement opening
202
c
is formed as a rectangle having a length of a long side and a length of a short side equal to A and B, respectively, and arcuately rounded corners, as shown in FIG.
5
. The driving pin
223
, engaged in this driving pin engagement opening
202
c
, is formed as a column having a diameter &phgr;C shorter than the length B of the short side of the driving pin engagement opening
202
c.
If the disc table
222
is run in rotation in the direction indicated by arrow R in
FIG. 5
, from an initial state in which magnetic disc
200
is set on the disc table
222
, with the spindle
221
passed through the spindle opening
202
b
and with the driving pin
223
engaged in the driving pin engagement opening
202
c
, as shown in
FIG. 5
, the driving pin
223
compresses against an outer corner of the driving pin engagement opening
202
c
disposed in the rotating direction of the disc table
222
, as shown in
FIG. 6
, to shift the magnetic disc
200
towards the outer rim of the spindle
221
. By the magnetic disc
200
being moved towards the outer rim of the spindle
221
by the driving pin
223
, the spindle
221
is abutted on the corner of the driving pin engagement opening
202
c
of the spindle opening
202
b
remote from the corner of the driving pin engagement opening
202
c
on which is abutted the driving pin
223
, as shown in
FIG. 6
, thus centering the hub
202
of the magnetic disc
20
Oosato Mamoru
Suzuki Hiroyuki
Tomita Yasushi
Maioli Jay H.
Ometz David L.
Sony Corporation
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