Disc cartridge having variable gap

Dynamic information storage or retrieval – Storage medium structure – Adjuncts or adapters

Reexamination Certificate

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Details

C206S308100

Reexamination Certificate

active

06233220

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a disc cartridge, for installing a disc-like information recording medium into an information recording and reproducing device which is used for recording information onto a disc-like information recording medium and for reproducing information from the disc-like information recording medium, and for keeping the disc-like information recording medium that is out of the information recording and reproducing device.
As a typical disc-like information recording medium, a flexible disc is known well, which is widely used as an information memorizing means for a personal computer and a word processor. Generally speaking, a flexible disc is housed in a plastic cartridge having a metal shutter that can slide for exposing a part of the flexible disc. When the cartridge including the flexible disc is installed into the information recording and reproducing device, this shutter is moved to slide by a shutter opening and closing mechanism disposed in the device.
In recent years, an optical disc and a magneto-optical disc are developed, which has extremely large memory capacity compared with the flexible disc. The optical disc and the magneto-optical disc are also housed in a plastic cartridge in the same manner as the flexible disc, for protecting recorded information, i.e., for preventing the information recording surface of the disc from being scratched or having adhesion of fingerprints.
The thickness of the optical disc or the magneto-optical disc is larger than the flexible disc. In addition, the optical disc or the magneto-optical disc rotates at a very high speed in the cartridge when recording or reproducing information. Furthermore, distortion of the disc surface and an eccentricity of the disc should be considered. For such reasons, sufficient clearance between the disc and the inner surface of the cartridge must be secured. Therefore, the cartridge including the optical disc or the magneto-optical disc is wide and thick compared with the disc itself.
In addition, the cartridge of the optical disc or the magneto-optical disc has a shutter in the same manner as that of the flexible disc. This shutter can be moved to slide on the cartridge so that the information recording and reproducing surface of the disc is exposed. This shutter is different from that of the flexible disc cartridge in that the sliding movement of the shutter is restricted by a lock mechanism provided to the cartridge. Thus, undesired exposure of the information recording and reproducing surface of the disc due to the sliding of the shutter is prevented when the disc cartridge is out of the information recording and reproducing device.
However, this lock mechanism of the cartridge needs tiny components for downsizing and thinning of the cartridge. Therefore, manufacturing of the cartridge requires a skill. In addition, a special mechanism for releasing the lock state of the lock mechanism is required to the information recording and reproducing device in which the cartridge is installed. Thus, cost increase cannot be avoided.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the problems mentioned above. A disc cartridge in accordance with the present invention is small and thin when it is out of the information recording and reproducing device, while a sufficient clearance between the disc and the inner surface of the cartridge is secured when it is installed in the information recording and reproducing device.
A disc cartridge in accordance with the present invention includes an upper lid and a lower lid for receiving a disc-like information recording medium therebetween, and variable means for making a gap between the upper lid and the lower lid variable.
Preferably, the variable means includes a cam portion provided to either one of the upper lid and the lower lid, and an engaging portion provided to the other, moving along the cam portion.
More preferably, the variable means further includes a hinge portion provided to either one of the upper lid and the lower lid.
It is also preferable that the upper lid and the lower lid be detachably connected to each other via the cam portion and the engaging portion.
Preferably, the disc cartridge in accordance with the present invention further includes at least a pair of guide means contacting the outer rim of the disc-like information recording medium held at the center portion in the disc cartridge. One of the guide means is provided to the upper lid, and the other is provided to the lower lid.
Still preferably, the disc cartridge in accordance with the present invention further includes a shutter sliding with respect to the upper and lower lids. The upper and lower lids have a first position where the gap therebetween is small, and a second position where the gap therebetween is large. The sliding movement of the shutter is restricted by the upper lid when the upper and lower lids are in the first position, and is performed when the upper and lower lids are in the second position.
It is also preferable that the shutter be moved away from the surface of the disc-like information recording medium housed in the disc cartridge along with the relative movement of the upper lid with respect to the lower lid.
In an embodiment, the variable means increases a clearance between the surface of the disc-like information recording medium and the inner surface of at least one of the upper and lower lids when the disc cartridge is inserted in an information recording and reproducing device.
In another embodiment, the variable means increases a clearance between the outer rim of the disc-like information recording medium and the inner wall of the disc cartridge contacting therewith when the disc cartridge is inserted in an information recording and reproducing device.
The disc cartridge according to the present invention is preferably used for an optical disc or a magneto-optical disc as the disc-like information recording medium.
These and other objects and advantages of the present invention will become clear from the description with reference to the accompanying drawings.


REFERENCES:
patent: 5208802 (1993-05-01), Suzuki et al.
patent: 5255251 (1993-10-01), Fitgerald et al.
patent: 5548577 (1996-08-01), Miyazaki et al.
patent: 5561657 (1996-10-01), Ogawa
patent: 5570337 (1996-10-01), Dang
patent: 5579297 (1996-11-01), Childers et al.
patent: 5719851 (1998-02-01), Yen
patent: 5903542 (1999-05-01), Sandell et al.

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