Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
1999-06-11
2001-08-07
Cao, Allen T. (Department: 2754)
Dynamic magnetic information storage or retrieval
Record medium
In container
C360S133000
Reexamination Certificate
active
06271991
ABSTRACT:
BACKGROUND OF THE INVENTION
One device for the storage of electronic data is a single-reel cartridge containing a length of recordable magnetic tape. One common type of cartridge employs a tape-feed reel with teeth disposed along a peripheral edge of the tape-feed reel and a toothed brake which serves to stop rotation of the reel by interlocking with the toothed reel. The tape is fed from the cartridge to a reading device through a hinged door in the surface of the cartridge. These cartridges are widely used throughout many industries, corporations, and similar entities for storage of crucial data, files, and information because they are inexpensive and capable of storing immense quantities of information.
These cartridges, however, can be damaged and rendered unusable by being dropped, or by the ordinary wear that arises from use over an extended period, such as several years. For example, the housing and door of these cartridges are currently composed of a composite material, such as polycarbonate reinforced with glass fibers. While these fibers make the plastic quite strong, they render the plastic brittle and susceptible to breakage. Breakage of either the door or the housing during impact leaves the data inaccessible and may even destroy the tape carrying the data. Additionally, routine use of the cartridge can erode the plastic, generating debris that can damage the tape, the reel or the reading device, resulting in increased errors in reading or recording the data.
Second, the teeth of the tape reel and of the brake can be quite fragile, and can break off when the cartridge is dropped. These loose teeth can damage the tape or the reading device, and can also become wedged under the reel, preventing normal rotation. Also, if the brake is no longer able to stop rotation of the wheel because of broken teeth, the leading end of the tape may get pulled into the reel, making retrieval of the tape impossible to the user.
Although the data can often be retrieved from a damaged cartridge in some cases, the delay incurred by the cartridge failure can be extremely costly to a company in terms of both time and money. In other cases, data critical to the function of a business or other enterprise can be irretrievably lost. Accordingly, a more rugged and durable device for storing such valuable and often irreplaceable data is urgently needed.
SUMMARY OF THE INVENTION
The systems and methods described herein relate to tape cartridges and methods for manufacturing tape cartridges that are resistant to breaking and wear. To this end, cartridges are disclosed that can include reinforcing ribs on the housing and door of the cartridge to protect against breakage. The reinforcing ribs are understood to increase the structural stiffness of the cartridge and to make the cartridge more robust. This allows the cartridge to be made of a material with a reduced glass fiber content. It is understood that glass fibers add to the structural strength of the cartridge, but reduce impact strength, increase the production of debris during normal use, and reduce the life of production tools that shape the cartridge. Additionally, the reel and brake of the cartridge can employ short teeth with widened roots that strengthen the teeth against shear forces which might cleave the teeth from the reel or the brake.
In one embodiment, the housing and the door are made of a material substantially free of glass fibers, increasing the impact strength relative to a material which includes glass fibers. In a related embodiment, the door and housing are further reinforced with at least one raised rib, and the door may be connected to the housing with a reinforced hinge. The raised ribs may be disposed laterally along the door or radially within the cartridge, or in any other disposition which provides structural reinforcement. In an additional embodiment, the housing includes interior walls which further reinforce the housing.
In a further embodiment, the teeth of the tape-feed reel mounted within the housing are connected to the reel by roots that widen to the base to provide resistance to shearing forces. Optionally, the teeth of the brake can also be connected to the brake by roots which widen at the base. The dimensions of the tooth can be selected according to the application, and in one embodiment, the length of a tooth and the width of a tooth at its base may be substantially similar in magnitude. In another embodiment, the widening roots of the teeth are half, or a third of the length of each tooth. In yet another embodiment, the width of a tooth at the base of the tooth is substantially similar to the thickness of the tooth at the base of the tooth, e.g., the cross-section of the base of the tooth is substantially square. In other embodiments, the cross-sectional area of the base of the tooth is greater than the area of the profile of the tooth. The profile of the tooth is the face of the tooth coplanar with the structure carrying the tooth, e.g., the face of the tooth coplanar with the flat surface of a tape-feed reel, as opposed to the edge of the tape-feed reel.
A second aspect of the invention provides methods for manufacturing a tape cartridge. In one practice, the method includes mounting within a housing a rotatable tape-feed reel with a peripheral edge carrying a plurality of teeth. Each tooth has a root coupling the tooth to the reel, and the root widens to render the tooth resistant to shearing. Furthermore, a brake with teeth, each tooth having a root coupling the tooth to the brake and having a shape complementary to a tooth of the reel, may be disposed within the housing such that engagement of the teeth of the brake with the teeth of the reel generates a braking force. Optionally, a door may be mounted to the housing with a hinge constructed for increased durability.
REFERENCES:
patent: 4802045 (1989-01-01), Yamamoto et al.
patent: 5189583 (1993-02-01), Okamura et al.
patent: 5492284 (1996-02-01), Sorensen
patent: 5517377 (1996-05-01), Suzuki et al.
patent: 5529256 (1996-06-01), Takahashi et al.
patent: 5530610 (1996-06-01), Katagiri et al.
patent: 5657936 (1997-08-01), Ohgi et al.
patent: 6038112 (2000-03-01), Kletzl
Hertrich Greg
Kim Chan
Mallick Satya
Saliba George A.
Stamm Stephen
Cao Allen T.
Quantum Corporation
Roeder Steven G.
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