Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Tape record
Reexamination Certificate
1999-05-20
2002-05-21
Ometz, David L. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Tape record
Reexamination Certificate
active
06392836
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a tape cartridge loader mechanism, for example, for loading a single-reel magnetic tape cartridge into a tape drive, to enable reading data from and writing data to the tape, and for unloading the cartridge from the tape drive.
BACKGROUND
Computers utilize a variety of magnetic media devices for the storage of software programs and data. Information recorded on the magnetic medium takes the form of flux transitions that represent the binary “1's” and “0's” that form the digital information. Tape cartridges, such as single-reel tape cartridges, are commonly used in library or other archival data storage applications. In such applications, a user or a robotic mechanism selects a tape cartridge for processing and inserts the cartridge into a tape drive coupled to a computer. In a fully automated system, a mechanism within the tape drive loads the tape from its entry point to a position in which the tape becomes accessible for read-from and write-to operations.
A variety of different size data tape cartridges are available. The drives for the different size cartridges, however, must be substantially the same size, so as to fit within a standard size slot or space available within the framework of a personal computer or the like. Larger cartridges enable storage of more data on the tape within, however, the larger the cartridge the more difficult it is to design a drive mechanism to fit within the design envelope.
For example, some single reel cartridges are 105.4 mm wide, by 102 mm long by 21.5 mm high. Such a cartridge, by itself fills a substantial portion of the design envelope for the tape drive. As a result, tape drives for this type of cartridge have utilized manual loading mechanisms. All movement and operations to load the tape cartridge into the drive, open the tape door for access to the tape leader and engage the tape drive gear to the drive motor gear have been manual in nature. A portion of the cartridge remains outside the drive, even in the fully loaded position.
Data cartridge tape drives have been developed with automatic or “soft” loading and unloading of the cartridge. However, because of the size and complexity of the loading mechanism, these automatic loaders have been used only in drives for smaller tape cartridges.
Also, automatic cartridge tape drives must be able to load and unload cartridges many times without jamming or other failures. A failure of an automatic loader mechanism may damage a tape cartridge and makes the drive unusable until repaired or replaced. Typical design parameters for drives available today call for the loader mechanism to continue to operate successfully for at least 300,000 loading/unloading cycles. For applications with frequent cartridge replacement, such as tape library systems providing access to volumes of data to many users via networks, to have a truly useful life each tape loader mechanism must operate successfully with little or no wear for many more cycles than even this design parameter.
Automatic loader mechanisms have been developed in the past that include some form of conveyor to retract the cartridge entirely within the drive and lower the cartridge for engagement with the tape drive motor gear. These mechanisms are motor driven and must include some means to convert the rotational motion of the motor into a complex motion of the conveyor during loading and unloading operations. The mechanisms for actuating the conveyors in such loaders have used complex linkage systems of two or more pivotal members, to achieve the necessary degrees of motion, to load and unload the cartridge. Such linkage systems take up considerable space within the design envelope of the tape drive, making it impossible to design an automatic drive for a relatively large cartridge. Also, such linkage systems are rather fragile. Such a linkage wears quickly and may be damaged by impact, either when the user inserts the cartridge with too much force or due to an external impact on the drive or computer housing.
It should, therefore, be appreciated that a need exists for an automatic loading mechanism for data tape cartridges that takes up the minimum amount of space within the design envelope of the tape drive, to allow the mechanism and the drive to handle as large a cartridge as possible. Also, a need exists for a loader mechanism of this type that is particularly durable and can operate successfully for a large number of loading/unloading cycles without any jams or other failures.
Furthermore, at least some cartridge tape drives use a magnet and a metal plate to form a magnetic clutch, to engage the cartridge gear to the drive gear associated with the motor. In an automatic loader, the loader motor must supply sufficient torque during unloading to overcome the magnetic clutch forces, in order to separate the cartridge from the cartridge drive motor. This imposes high torque and power requirements on the loader motor. To produce adequate torque typically requires a larger motor and more electrical power. The high torque also tends to wear out drive linkages quickly.
A specific need exists for a technique to reduce the torque requirement on the loader motor needed to separate the magnetic clutch elements, to allow use of a smaller motor and reduce stress and wear on loader components. However, any solution intended to reduce this torque requirement must not inordinately increase size or complexity of the loader or compromise its durability.
SUMMARY OF THE INVENTION
The present invention meets the above-stated needs and overcomes the problems with prior cartridge loader systems.
A tape cartridge loader in accord with a first aspect of the invention includes a moveable shuttle for receiving the tape cartridge and means for actuating the shuttle during loading and unloading operations. The means are adapted to occupy minimal space within the loader. Also, the actuating means require minimal motor torque, particularly during initial operation for unloading a tape cartridge.
Another aspect of the present invention relates to an automatic tape cartridge loader. The loader includes a mechanism for receiving the tape cartridge. In response to a linear actuation, the loader mechanism moves the cartridge into operative engagement with a data tape drive. The loader also includes means for applying the linear actuation to the loader mechanism.
The preferred embodiments include a number of unique elements as part of the actuating means. For example, to actuate a linear motion of the shuttle, the loader includes a rotatable actuator arm. The arm is substantially flat. The arm includes a groove at a distance from its axis of rotation. The groove edges serve as cam profiles, to drive a bearing attached to a conveyor to move the conveyor along a linear path during loading and unloading operations. The groove edges are contoured to maintain substantially 90° contact with a circumference of the bearing, during each linear motion of the bearing and conveyor. The actuator also preferably conveyor interacts through a cam profile and follower arrangement to produce the necessary movement of the shuttle, during loading and unloading operations.
The use of the flat actuator arm and cam follower minimizes the height of the elements for converting the motive force into a linear actuation of the conveyor. Also these elements are relatively simple and durable. The selection of the cam profile contour, to maintain perpendicular force on the follower bearing provides efficient transfer of linear force, preferably to push the follower and the conveyor. The torsion spring may serve a number of different functions. If the cam profile is that used during loading, the spring biases the follower bearing into engagement with the profile and provides impact buffering between the conveyor and the actuator arm, to absorb impacts due to insertion of the tape cartridge. If the cam profile is that used in an unloading operation, the torsion spring actually helps to push the follower bearing and thus the conveyor.
Other unique el
McDermott & Will & Emery
Ometz David L.
Seagate Removable Storage Solutions LLC
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