Automatic up-and-down disc clamping apparatus with magnets

Electrical generator or motor structure – Dynamoelectric – Rotary

Reexamination Certificate

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Details

C369S270100, C369S075210

Reexamination Certificate

active

06316854

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority benefit of Taiwan application serial no. 88120151, filed Nov. 18, 1999.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a disc clamping apparatus. More particularly, the present invention relates to an automatic up-and-down disc clamping apparatus with magnets.
2. Description of the Prior Art
In 1997, the DVD Alliance published a DVD-RAM standard in which a disc with a cartridge is revealed. A thickness of the cartridge is about 8 mm. Interference between the cartridge and a disc clamp may occur while loading or ejecting the cartridge. Interference means that a position of the disc clamp is not high enough so that the disc clamp touches the cartridge during the loading or ejecting process. Damage to the cartridge may occur or data stored in the disc may even be lost.
Currently designs in disc clamping apparatus for disc players employ an elastic lever mechanism constructed in a chucking plate to lift up a disc clamp. Reference is made to
FIGS. 1A and 1B
, which illustrate schematic views of a prior art disc clamping apparatus and its operating movement. As shown in
FIG. 1A
, when a cartridge holder
10
of a disc player is moved in a loading state outside the disc player, an elastic lever mechanism
30
constructed in the chucking plate
20
begins to operate.
When a contact rod
32
of the elastic lever mechanism
30
is separated from the cartridge body
10
, an elastic device
38
causes a lever rod
36
of the elastic lever mechanism
30
to rotate with a hinge point
34
as a pivot center such that a disc clamp
40
is lifted up. Therefore, interference between the disc clamp
40
and a cartridge is prevented.
Reference is made to
FIG. 1B
, in which the cartridge holder
10
is moved back into the disc player. When the cartridge holder
10
makes contact with the contact rod
32
, the elastic device
38
is compressed. The lever rod
36
is rotated with the hinge point
34
as the pivot center such that the disc clamp
40
is lowered down and clamped onto a disc. Finally, a spindle motor (not shown) is lifted up. The disc is then supported by the spindle motor. At this moment, the disc is secured by the disc clamp
40
and the spindle motor. Rotation of the disc follows and data can be read or written on the rotating disc.
Unfortunately, the prior art elastic lever mechanism
30
has a lot of components. Its assembly is not easy. Moreover, the up-and-down motion of the elastic lever mechanism
30
requires a large operating space. All of these problems increase the complexity of a structural design for a disc player.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides an automatic up-and-down disc clamping apparatus with magnets. A spindle motor is lifted up to an attachment position and a magnetic conductive material inside a disc clamp is then attracted by a circular ring magnet in a turntable on the spindle motor. When the spindle motor is lowered down, the magnetic conductive material is attracted by a circular ring magnet on a chucking plate. Thus, the disc clamp is moved up-and-down automatically, and interference with a cartridge or a disc is prevented.
The present invention provides an automatic up-and-down disc clamping apparatus with magnets, in which an operating space and the number of components are both reduced.
The present invention provides an automatic up-and-down disc clamping apparatus with magnets, in which the complexities of design and assembly are reduced, and collisions between devices can be avoided.
The present invention provides an automatic up-and-down disc clamping apparatus with magnets, which is described as follows.
A spindle motor has a shaft portion, wherein a turntable is fixed on top of the shaft portion such that the shaft portion is encased in a center of the turntable. The turntable is brought into rotation by the spindle motor. A disc is supported by the turntable when the spindle motor is lifted up to an attachment position. A first magnet is fixed to the turntable, and a locking plate has a surface facing the turntable on the spindle motor. A second magnet is fixed to the locking plate. A disc clamp, which has a magnetic conductive material within, is attached to the locking plate by an attraction of the second magnet. When the spindle motor is in the attachment position, the disc clamp is clamped onto the disc by an attraction of the first magnet.
The present invention provides an automatic up-and-down disc clamping apparatus with magnets, which is described as follows.
A spindle motor has a shaft portion, wherein a turntable is fixed on top of the shaft portion such that the shaft portion is encased in a center of the turntable. The turntable is brought into rotation by the spindle motor. A disc is supported by the turntable when the spindle motor is lifted up to an attachment position. A first magnet is fixed to the turntable. A chucking plate has a recess and the recess opening faces the turntable on the spindle motor. A second magnet is fixed to a bottom of the recess. A disc clamp, which has a magnetic conductive material within, is attached to the bottom of the recess by an attraction of the second magnet. When the spindle motor is in the attachment position, the disc clamp is clamped onto the disc by an attraction of the first magnet.


REFERENCES:
patent: 4477894 (1984-10-01), Clurman
patent: 4510592 (1985-04-01), Kanamaru et al.
patent: 4539671 (1985-09-01), Higashihara
patent: 4561084 (1985-12-01), Satake et al.
patent: 4730299 (1988-03-01), Kamoshita et al.
patent: 4823337 (1989-04-01), Van Zanten et al.
patent: 4951277 (1990-08-01), Masunaga et al.
patent: 5001700 (1991-03-01), Rowden et al.
patent: 5388094 (1995-02-01), Park
patent: 5668792 (1997-09-01), Choi
patent: 5671210 (1997-09-01), Goto

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