Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
1998-06-19
2001-08-14
Miller, Brian E. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
Reexamination Certificate
active
06275355
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a magnetic disc cartridge which comprises a large capacity magnetic disc medium contained in a casing and is used in a magnetic recording and reproduction in which the magnetic disc medium is rotated at high speed, and more particularly to such a magnetic disc cartridge which is provided with a means for preventing the magnetic disc cartridge from being loaded in a magnetic disc drive system for smaller capacity magnetic disc cartridges. Further this invention relates to a magnetic disc drive system for driving the large capacity magnetic disc cartridge.
BACKGROUND
There has been known a magnetic disc, a so-called floppy disc, which comprises magnetic layers formed on opposite sides of a flexible disc base of a polyester sheet or the like. Information is recorded on the floppy disc by a magnetic head while rotating the floppy disc at high speed. Such floppy discs have been mainly used as recording media for computers because they are easy to handle and can be produced at low cost.
Recently the magnetic disc of this type is generally held for rotation in a small hard casing and used in the form of a magnetic disc cartridge as represented by a 3.5-inch floppy disc.
In the magnetic disc cartridge with a hard casing, the casing is provided with an opening for giving a magnetic head access to the magnetic disc therein and the opening is normally closed by a shutter urged in one direction so that foreign matters such as dust cannot enter the casing.
There has been constant demand for a magnetic disc cartridge having a larger storage capacity and 3.5-inch floppy discs having a storage capacity of 1 MB or 2 MB have been put into practice. Further even 3.5-inch floppy discs having a storage capacity of not smaller than 100 MB have been provided.
When a magnetic disc cartridge larger than conventional magnetic disc cartridges in storage capacity is developed, a novel disc drive system for driving the magnetic disc cartridge having a larger storage capacity is sometimes provided. Such a novel disc drive system is generally arranged to be able to drive magnetic disc cartridges having smaller storage capacities as well as the newly developed larger capacity magnetic disc cartridge. Such capability of driving magnetic disc cartridges having smaller storage capacities as well as the newly developed larger capacity magnetic disc cartridge will be referred to as “downward compatibilities”, hereinbelow.
In order to provide a disc drive system with such downward compatibilities, the newly developed larger capacity magnetic disc cartridge should be substantially the same as the conventional magnetic disc cartridges in appearance and the like. Accordingly, there is fear that the newly developed larger capacity magnetic disc cartridge is loaded in a disc drive system for the conventional smaller capacity magnetic disc cartridges. The disc drive system for the conventional smaller capacity magnetic disc cartridges will be referred to as “smaller-disc drive system” and the disc drive system for newly developed larger capacity magnetic disc cartridges will be referred to as “larger-disc drive system”, hereinbelow.
Generally the smaller-disc drive system is not provided with function for satisfactorily protecting the newly developed larger capacity magnetic disc cartridge, and when the disc drive system is operated loaded with the newly developed large capacity magnetic disc cartridge, information stored in the magnetic disc can be destroyed.
Though accidental recording or erasure can be prevented by providing, for instance, a hole for distinguishing the storage capacity on cartridges, when a larger capacity magnetic disc cartridge is accidentally loaded in a smaller-disc drive system and a magnetic head of the smaller disc drive system is brought into contact with the magnetic disc medium in the magnetic disc cartridge, there is fear that foreign matters or dust on the magnetic head adhere to the magnetic disc medium.
Since the larger capacity magnetic disc is obtained by increasing the recording density, the recording wavelength is shorter and the recording track is narrower. Accordingly when foreign matters are on the larger capacity magnetic disc medium, errors can be generated in reading out recorded data.
In view of the foregoing observations and description, the primary object of the present invention is to provide a larger capacity magnetic disc cartridge which cannot be loaded in a disc drive system exclusively for a magnetic disc cartridge having a smaller storage capacity.
Another object of the present invention is to provide a disc drive system for larger capacity magnetic disc cartridges.
DISCLOSURE OF THE INVENTION
A larger capacity magnetic disc cartridge in accordance with the present invention comprises a larger capacity magnetic disc medium held for rotation in a casing provided with an opening which gives a magnetic head access to the magnetic disc medium and is normally closed by a shutter. The casing is provided with a first cutaway portion at a front corner between the front edge and one side edge of the casing. The first cutaway portion is common to that of a smaller capacity magnetic disc cartridge for preventing insertion of a smaller capacity magnetic disc cartridge into the disc drive system in a wrong direction. The larger capacity magnetic disc cartridge in accordance with the present invention is characterized in that a second cutaway portion which is adapted to engage with an engagement member of the smaller-disc drive system which is brought into engagement with the first cutaway portion and is displaced is formed on said one side edge of the casing.
When the larger capacity magnetic disc cartridge of the present invention is inserted into the smaller-disc drive system, the engagement member of the disc drive system is displaced laterally or vertically by the first cutaway portion to permit insertion of the larger capacity magnetic disc cartridge to some extent. However when the engagement member comes to engage with the second cutaway portion, further insertion of the magnetic disc cartridge is prevented and accordingly the shutter of the magnetic disc cartridge is not opened.
For example, the second cutaway portion of the casing may comprise an inclined surface inclined inward from the front end of the second cutaway portion, a shoulder portion which extends substantially normal to the side edge at the rear end of the second cutaway portion and a parallel portion substantially parallel to the side edge and is substantially trapezoidal in shape. This arrangement of the second cutaway portion is especially useful in surely bringing the engagement member into engagement with the second cutaway portion when the engagement member is displaced vertically upon abutment against the first cutaway portion.
The engagement member can be more surely brought into engagement with the second cutaway portion when the distance of the parallel portion from the side edge of the casing is substantially equal to or larger than the length by which the corner of the casing is cut to form the first cutaway portion as measured in the direction normal to the side edge and the length of the parallel portion as measured in the direction of the side edge is substantially equal to or larger than the width of the engagement member of the smaller-disc drive system as measured in the direction of the side edge of the magnetic disc cartridge.
Further when the second cutaway portion has said inclined surface, the engagement member in engagement with the second cutaway portion can be easily disengaged from the second cutaway portion when the magnetic disc cartridge is drawn.
When the casing is not provided on its front edge with a recess for inserting a shutter opening lever, the larger capacity magnetic disc cartridge can also be prevented from being loaded in a smaller-disc drive system in which insertion of a smaller capacity magnetic disc cartridge in a wrong direction is prevented not by an engagement member but by a shutter opening lever which is to
Brinks Hofer Gilson & Lione
Fuji Photo Film Co. , Ltd.
Miller Brian E.
Nichols G. Peter
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