Dynamic information storage or retrieval – Dynamic mechanism subsystem – Specific detail of storage medium support or motion production
Reexamination Certificate
2001-02-22
2003-05-27
Cao, Allen (Department: 2652)
Dynamic information storage or retrieval
Dynamic mechanism subsystem
Specific detail of storage medium support or motion production
Reexamination Certificate
active
06570836
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a disk clamping mechanism, more precisely relates to a disk clamping mechanism for a disk drive unit, which drives a disk-shaped memory medium, e.g., a CD-ROM, a CD-R, a CD-RW, a DVD-ROM.
A conventional disk clamping mechanism of a disk player will be explained with reference to
FIGS. 4 and 5
.
The disk clamping mechanism
10
includes: a turntable
12
on which a disk-shaped medium (not shown), e.g., a compact disk, will be mounted; and a clamper
14
, which is magnetically drawn toward and held on the turntable
12
so as to clamp the disk-shaped medium between the turntable
12
and the clamper
14
.
The turntable
12
is formed into a disk shape. A columnar section
16
is provided to a center of an upper face of the turntable
12
. The columnar section
16
will be fitted into a center hole of the disk-shaped medium so as to coincide an axial line of the disk-shaped medium with that of the turntable
12
. A circular supporting section
18
, which is capable of supporting a bottom face of the disk-shaped medium, is formed in the upper face and along an outer edge of the turntable
12
. The turntable
12
is usually directly connected to an output shaft (not shown) of a spindle motor
20
. The spindle motor
20
rotates the turntable
12
.
A circular hole
22
is bored in an upper end face of the columnar section
16
. The circular hole
22
is coaxial with the columnar section
16
and the turntable
12
. A ring magnet
24
is fixed in the upper end face of the columnar section
12
and encloses the circular hole
22
. Tongue pieces
26
are provided in an outer circumferential face of the columnar section
16
with regular angular separation's. The tongue pieces
26
are capable of engaging with the center hole of the disk-shaped medium when the disk-shaped medium is inserted into the disk drive unit
40
(see FIGS.
6
and
7
). Therefore, the disk-shaped medium can be clamped without play.
The supporting section
18
is usually made of a rubber ring so as to increase frictional force between the supporting section
18
and a bottom face of the disk-shaped medium, so that the disk-shaped medium can be securely clamped.
The damper
14
is formed into a circular disk. The clamper
14
has a circular pressing section
28
, which is formed in a bottom face and along an outer edge of the clamper
14
. The clamper
14
is magnetically drawn toward the upper face of the turntable
12
so as to clamp the disk-shaped medium between the supporting section
18
of the turntable
12
and the pressing section
28
of the clamper
14
. Namely, the disk-shaped medium will be held in a space “A”.
A planar ring
30
, which is made of a magnetizable metal, is provided and exposed in the bottom face of the clamper
14
. The planar ring
30
is coaxial with the axial line of the clamper
14
. The planar ring
30
is fixed in a circular groove
32
, which is formed in a center part of the bottom face of the clamper
14
.
A positioning boss
34
is formed into a columnar shape and projected downward from the center of the bottom face of the clamper
14
. The positioning boss
34
is coaxial with the clamper
14
. The planar ring
30
encloses the positioning boss
34
. The positioning boss
34
can be inserted into the circular hole
22
when the clamper
14
is magnetically drawn toward the turntable
12
, so that the axial line of the clamper
14
can be coincided with that of the turntable
12
. Outer diameter of the positioning boss
34
is nearly equal to inner diameter of the circular hole
22
so as to smoothly go into and out from the circular hole
22
.
In
FIG. 4
, the spindle motor
20
is attached to a circuit board
36
, to which stator coils (not shown) of the spindle motor
20
are electrically connected. Rotation detecting elements, e.g., haul elements, are provided to the circuit board so as to detect rotational speed of a rotor of the spindle motor
20
. Cables
38
, which are capable of supplying electric power to the spindle motor
20
and sending signals of the rotation detecting elements, etc. outside, are electrically connected to the circuit board
36
.
As shown in
FIGS. 6 and 7
, in the disk clamping mechanism having the turntable
12
and the clamper
14
, a clamper holding plate
44
is usually fixed to an upper part of a casing
42
of the disk drive unit
40
. The clamper
14
is rotatably attached to the clamper holding plate
44
and is capable of slightly moving up and down with respect to the clamper holding plate
44
.
A tilt table
46
is provided under the damper holding plate
44
. The turntable
12
, the spindle motor
20
and the circuit board
36
are fixed to the tilt table
46
.
The tilt table
46
is tilted downward and upward when a disk tray, which conveys the disk-shaped medium to a position corresponding to an optical pickup of the disk drive unit
40
, is set into and taken out from the disk drive unit
40
. Namely, the tilt table
46
is tilted down when the disk tray is taken out from the disk drive unit
40
; the tilt table
46
is tilted up after the disk tray is set in the disk drive unit
40
.
When the tilt table
46
is tilted up, the turntable
12
, which is attached to the tilt table
46
, is moved close to the clamper
14
. Then, the clamper
14
is magnetically drawn toward and held on the turntable
12
. After that, the tilt table
46
is further slightly tilted up and stopped. With this action, the turntable
12
holds the clamper
14
. In this state, the clamper
14
is slightly floated from the clamper holding plate
44
and capable of freely rotating with respect to the clamper holding plate
44
. If the disk-shaped medium is mounted on the disk tray when the tilt table
45
is tilted up, the disk-shaped medium is firstly mounted onto the turntable
12
, then the disk-shaped medium, which has been supported by the turntable
12
, is moved close to the clamper
14
, so that the disk-shaped medium is clamped between the turntable
12
and the clamper
14
, which is magnetically drawn toward the turntable
12
. With this action, the disk-shaped medium can be rotatable held on the turntable
12
.
On the other hand, when the tilt table
46
is tilted down, the clamper
14
, which has been magnetically held by the turntable
12
, is moved away therefrom, against the magnetic force of the ring magnet
24
, by moving the turntable
12
away from the clamper holding plate
44
.
As described above, even if the disk-shaped medium is not mounted on the disk tray, the clamper
14
is moved close to and away from the turntable
12
when the disk tray is set into and taken out from the disk drive unit
40
.
In the conventional disk clamping mechanism
10
having the turntable
12
and the lamper
14
, a distance between a surface of the ring magnet
24
of the turntable
12
and a surface of the planar ring
30
of the clamper
14
is quite different in a first state, in which the disk-shaped medium is mounted on the turntable
12
, and a second state, in which no disk-shaped medium is mounted on the turntable
12
. The reason is that outer diameter of the positioning boss
34
, which is formed at the center of the bottom face of the clamper
14
, is wholly shorter than inner diameter of the circular hole
22
, which is bored in the upper face of the columnar section
16
of the turntable
12
, a base section of the positioning boss
34
is fully inserted into the circular hole
22
when the clamper
14
is magnetically held by the turntable
12
, and the upper end of the columnar section
16
, in which the ring magnet
24
is provided, nearly contacts the bottom face of the planar ring
30
.
In the case that the no disk-shaped medium is clamped between the turntable
12
and the clamper
14
and the distance “B” (see
FIG. 5
) between the surface of the ring magnet
24
of the turntable
12
and the surface of the planar ring
30
of the clamper
14
is very short, greater force is required to move the clamper
14
away from the turntable
12
because magnetic force is in inv
Cao Allen
Shinano Kenshi Kabushiki Kaisha
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