Dynamic information storage or retrieval – With particular cabinet structure
Utility Patent
1997-09-16
2001-01-02
Miller, Brian E. (Department: 2757)
Dynamic information storage or retrieval
With particular cabinet structure
C369S263100
Utility Patent
active
06169718
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a disk drive unit for recording and reproducing information to and from a recording medium, and more particularly to a locking plate within the disk unit for stabilizing insertion of the disk into the disk drive.
2. Description of the Related Art
A recording medium such as, for example, an optical disk unit, is generally used for writing and/or reading an information signal to and/or from the disk rotatably set in a disk cartridge. For example, a “min-disk system” including a loading mechanism is described in
Nikkei Mechanical
, No. 479, Apr. 29, 1996, pp. 64-67. Another type of optical recording system, namely a video camera using a magnetic tape, is described in “Development of
8
mm VCRs”, Jun Hirai,
Technical Meeting of Industrial Precision Society
, Vol. 61; , No. 1, 1995.
Referring back to the optical disk unit, the disk unit comprises a cartridge loading mechanism having a cartridge holder for removably holding a disk cartridge, a disk table positioned under the cartridge loading mechanism to attract and hold an optical disk, a rotary drive mechanism having a spindle motor for driving the disk table at high speed, and an optical pickup device, positioned behind the rotary drive mechanism, having an objective lens.
In operation, the disk cartridge is moved to a predetermined cartridge loading position. An optical disk within the disk cartridge is rotated to the cartridge loading position (e.g., the disk loading position), and an information signal is written to and read from the optical disk.
Because the disk cartridge advantageously has a large memory capacity and superior accessibility, portability, and durability, the optical disk cartridge operates well with, for example, a portable video camera. However, the disk drive must be protected from vibrations and impacts, when recording or reproducing data to or from the cartridge.
As shown in prior art
FIG. 6
, an exemplary portable video camera
1
includes a camera body
2
, a lens barrel
3
, a viewfinder
4
, and a carrying handle
5
. The camera body
2
has a disk unit frame
6
and a cover
7
for pivotally opening or closing an aperture
6
a
of the disk unit frame
6
. The disk unit frame
6
includes a pickup device (illustrated in
FIG. 8
with reference numeral
14
) and a printed circuit board (not illustrated). The cover
7
is connected to a main chassis (not illustrated), via hinges or the like, so as to be rotatable in the directions shown by arrows m
1
and m
2
about an axis line A, shown in FIG.
7
.
A conventional disk unit uses a damper
10
, such as an elastic insulator including a rubber grommet, for elastically securing a sub-chassis
8
, as shown in
FIGS. 6 and 7
. The sub-chassis
8
includes side walls
8
a
and
8
b
facing each other and has a substantially U-shaped cross-section, and is secured to the back of the lid
7
. A disk drive
9
is elastically connected to the sub-chassis by the damper. The damper comprises four rubber grommets
10
inside of the side walls of the sub-chassis
8
, as shown in FIG.
7
. The disk drive
9
includes a disk drive frame
12
having a cartridge inserting/extracting port
12
a
through which a disk cartridge
11
is inserted or extracted. The disk drive frame
12
moves inside and outside of the disk unit
6
by rotating the lid
7
.
As shown in
FIG. 8
, the disk drive includes a spindle motor
13
for rotating a disk
11
a
in the disk cartridge
11
, an optical pickup device
14
for reading and writing data to and from the disk
11
a
, and a pickup device actuator (not illustrated) for moving the optical pickup device
14
forward and backward in a tracking direction, to allow the optical pickup device to read the tracks on the optical disk.
Damper elements
10
in
FIG. 8
function as elastic insulators.
In operation, the disk cartridge
11
is inserted into or extracted from the disk drive frame
12
by rotating the lid
7
in the direction of arrow m
1
or m
2
in FIG.
6
. The rotating of the lid
7
opens or closes the aperture
6
a
of the disk unit frame
6
.
With such a conventional optical disk unit, to protect the disk drive
9
from vibrations and impacts when recording and reproducing data, the disk drive
9
must be secured elastically to the sub-chassis
8
(thereby increasing an allowable amplitude), so that the primary resonance frequency of the disk drive frame
12
is optimally decreased.
However, to increase the disk drive's ability to absorb vibrations (e.g., increasing the allowable amplitude), more movement/compensation (e.g., “play”) must be provided between the disk drive
9
and the sub-chassis
8
. However, such excess movement prevents the disk cartridge
11
from being smoothly inserted into or extracted from the disk drive frame
12
, since the sub-chassis is not fixed (e.g., is movable) during insertion of the disk cartridge.
Hence, a trade-off exists between the ease of insertion/extraction and the ability to absorb vibrations. A conventional disk drive which readily absorbs vibrations is problematic in the disk insertion/extraction operations because of the excessive freedom of movement. While a disk drive that is relatively stable (e.g., fixed) allows easy insertion/extraction of the disk, such a disk drive will not absorb vibrations as readily. Therefore, conventional disk drives are built to compromise (e.g., trade-off) these mutually exclusive objectives. Vibrations exhibited by such a conventional structure are illustrated in FIG.
9
.
Specifically,
FIG. 9
shows a disk rotating frequency transfer function curve (e.g., frequency of vibration) “a” of an optical disk (at a revolution speed of 70 rps) in the focus direction of the optical disk. The focus direction of the optical disk is the direction perpendicular to the tracks of the optical disk and opposed to the objective lens.
The lens actuator movement transfer function of an objective lens actuator of an optical pickup device is shown by curve “b”, frequency curve “c” is a damping mechanism transfer function according to the mass characteristic law (e.g., where m{umlaut over (u)}+c{dot over (u)}+ku=f(t), thereby representing the damping mechanism transfer function), an actual frequency of the disk drive when elastically holding a disk drive by a rubber grommet is shown by frequency curve “d”, and a spectrum curve of the disk drive when an external vibration is applied is shown by curve “e”. g
1
and g
2
represent frequency “spikes” showing outside (external) shock imparted to the system, and represent harmful frequencies to the system.
Thus, curve “a” is the disk rotation frequency transfer function curve, curve “b” is a lens actuator movement transfer function, curve “c” is a damping mechanism transfer function, curve “d” is another damping mechanism transfer function, and curve “e” represents when an external vibration is applied to the disk drive.
As shown in
FIG. 9
, the two large waveforms (“spikes”) g
1
, g
2
appear in the frequency area at an optical-disk revolution speed of approximately 70 rps or less, and the amplitudes of these vibrations have values exceeding the frequency curve “d.” Thus,
FIG. 9
illustrates that the vibration-resistant structure of conventional disk units (e.g., the grommets
10
) are insufficient to maintain such vibrations below the frequency curve “d.”
As a result, the lens and lens actuator do not operate reliably, and the disk drive unit cannot perform high-quality data recording and reproduction, and for smoothly inserting and extracting a disk cartridge in and from a disk unit, and in which the lens and lens actuator operate reliably.
SUMMARY OF THE INVENTION
In view of the foregoing and other problems of the conventional systems, an object of the present invention to provide a structure for performing high-quality data recording and reproduction, and for smoothly inserting and extracting a disk cartridge in and from a disk unit.
In a first aspect, a disk drive according to the present invention includes a
Fields Kenneth W.
McGinn & Gibb, P.C.
Miller Brian E.
NEC Corporation
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