Dynamic information storage or retrieval – Dynamic mechanism subsystem – Specified detail of transducer assembly support structure
Reexamination Certificate
1998-04-16
2001-06-19
Miller, Brian E. (Department: 2153)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Specified detail of transducer assembly support structure
Reexamination Certificate
active
06249504
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an anti-vibration mechanism and a disk drive device using the same and, more specifically, to an anti-vibration mechanism suitable for use in a small-sized drive device for driving disks, such as CDs (compact disks), CD-ROMs (CD-read only memories), MO (magneto-optical memories) and DVDs (digital versatile disks), and a disk drive using the same.
2. Description of the Related Art
Generally speaking, external vibrations, impacts, etc. are applied to an optical or a magnetic disk drive device. Such vibrations, etc. applied during reproduction cause reading errors to thereby generate errors in reading data, etc.
Conventionally, such errors in reading data due to external vibrations, etc. have been prevented by a structure as shown in
FIGS. 7 through 9
.
FIG. 7
is an essential-part sectional view illustrating a conventional anti-vibration mechanism;
FIG. 8
is a plan view showing a conventional disk drive device; and
FIG. 9
is a plan view showing a first chassis of a conventional disk drive device. As shown in
FIGS. 7 through 9
, this disk drive device is at least equipped with a first chassis
1
supported by an outer case (not shown), and a second chassis
2
which carries a rotation drive motor
25
to which a turntable
24
is mounted, a reproduction head
20
consisting of an optical head or the like, etc.
Formed in the upper wall
1
a
on the upper side of the first chassis
1
are a substantially rectangular first hole
1
b
, situated at the center thereof, a substantially rectangular second hole
1
c
connected to the first hole
1
b
, and a plurality of circular mounting holes
1
g
arranged along the longitudinal side edges of the first hole
1
b
(for example, two on either side, i.e., four in total).
Arranged on the second chassis
2
are a carriage
21
carrying the reproduction head
20
, a screw shaft
22
for driving this carriage
21
in the X-direction, a stepping motor
23
for rotating this screw shaft
22
intermittently, and the rotation drive motor
25
, to which the turntable
24
is mounted. Further, on opposing longitudinal side edges
2
b
of the second chassis
2
, there are formed a plurality of (for example, two on either side, i.e., four in total) mounting members
2
c
upwardly bent into an L-shape and having a fork-like forward-end configuration.
The first chassis
1
and the second chassis
2
are arranged so as to be opposed to each other, and the positions at which the plurality of mounting holes
1
g
of the first chassis
1
are formed respectively correspond to the positions at which the plurality of mounting members
2
c
of the second chassis
2
are formed, the two chassis
1
and
2
being attached to each other at these positions. The reproduction head
20
, the carriage
21
, the rotation drive motor
25
, etc. are exposed through the first hole
1
b
of the first chassis
1
.
In this disk drive device, the second chassis
2
is suspended from the first chassis
1
by means of an anti-vibration mechanism B using a plurality of (for example, four) vibration proof rubber members, whereby external vibrations, etc. from the first chassis
1
are prevented from being transmitted to the second chassis
2
.
FIG. 7
is an essential-part sectional view illustrating a conventional anti-vibration mechanism B. The fork-shaped mounting member
2
c
of the second chassis
2
is engaged with a peripheral groove
11
a
of a cylindrical vibration proof rubber member
11
. Passed through the circular mounting hole
1
g
of the first chassis
1
is a screw portion
10
b
provided on a support portion
10
a
of a cylindrical bolt
10
passed through a central hole
11
b
of the vibration proof rubber member
11
. The screw portion
10
b
is threadedly engaged with a hexagon nut
12
, whereby the bolt
10
is fastened to the mounting hole
1
g,
thereby enabling the second chassis
2
to be suspended from the first chassis
1
through the intermediation of the vibration proof rubber member
11
.
When the second chassis
2
is thus suspended from the first chassis
1
through the intermediation of the vibration proof rubber members
11
constituting the plurality of anti-vibration mechanisms B, the height dimension between the upper wall (upper surface) of the first chassis
1
and the upper surface of the turntable
24
, mounted to the rotation drive motor
25
arranged on the second chassis
2
, is definitely determined.
The height dimension between the upper wall (upper surface) of the first chassis
1
and the upper surface of the turntable
24
, definitely determined, cannot be adjusted.
Due to their nature, the vibration proof rubber members
11
must be held in a state in which no such stress as torsion or compression is applied thereto since it is difficult to maintain the requisite dimensional accuracy in machining and a predetermined spring constant must be maintained.
The positioning of the first chassis
1
with respect to the second chassis
2
in the X and Y-directions is effected by inserting the cylindrical bolts
10
, which extend through the central holes
11
b
of the plurality of vibration proof rubber members
11
, into the circular mounting holes
1
g
of the first chassis
1
and threadedly engaging the bolts
10
thus inserted with the hexagon nuts
12
.
Nowadays, in disk drive devices required to be thinner and disk drive devices equipped with a changer mechanism in which a plurality of disks are stacked together, there are heavier demands for high accuracy in the dimensions of each member constituting the drive device. In the above-described conventional anti-vibration mechanism B, however, the distance between the first chassis
1
and the second chassis
2
is determined by the machining dimension of the vibration proof rubber members (vibration proof members) arranged between the first chassis
1
and the second chassis
2
. This leads to a problem in that it is difficult to maintain the requisite dimensional accuracy of the vibration proof rubber members, and, consequently, it is difficult to maintain high accuracy in the distance between the first chassis
1
and the second chassis
2
.
Further, the mounting of the vibration proof rubber members to the first chassis is effected by forcing the mounting bolts into the central holes of the vibration proof rubber members and threadedly engaging the bolts with the hexagon nuts, so that, when engaging the hexagon nuts with the bolts, the bolts rotate with the nuts, with the result that torsional stress is applied to the vibration proof rubber members into which the bolts have been forced. This stress applied to the vibration proof rubber members causes variation in the spring constant of the vibration proof rubber members to be generated, with the result that a desired anti-vibration performance cannot be achieved.
Further, due to the deterioration in elasticity as a result of change with time, the height of these vibration proof rubber members increases (i.e., they extend further downwards), so that the position of the turntable mounted to the second chassis is also lowered. Due to the construction in which the distance between the first chassis and the second chassis cannot be adjusted, nothing can be done about this change with time.
Further, the above change with time does not always occur in the same manner in the four vibration proof rubber members. Variation can sometimes occur between the four vibration proof rubber members, with the result that there is variation in the heights of the vibration proof rubber members. As a result, the parallelism of the turntable cannot be maintained, so that the disk is tilted.
Further, when mounting the second chassis to the first chassis, the screw portions of the cylindrical mounting bolts are passed through the circular mounting holes provided in the first chassis, and the hexagon nuts are threadedly engaged therewith. In this mounting operation, the screw portions of the cylindrical bolts are passed through the circular mounting holes, with the
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Fields Kenneth W.
Miller Brian E.
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