Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Tape record
Reexamination Certificate
1999-09-01
2001-09-18
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Tape record
Reexamination Certificate
active
06292325
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a gear and actuator of a tape cartridge loader mechanism, for example, for a mechanism for loading a single-reel magnetic tape cartridge to and from a tape drive, to enable reading data from and writing data to the tape.
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, to allow a person to grip a portion of the cartridge to pull the cartridge from the drive.
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 such a failure 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.
Also, where the prior mechanisms have utilized gears, the drive gears have been “in-line” with the associated linkages or arms, to transfer motive torque to the cartridge shuttle system. For example, if a gear is in-line with the attached linkage or arm, that is to say in approximately the same plane, the driving of the linkage or arm provides efficient conversion to torque on the linkage or arm, without imparting any moment of force in any direction that is out of the plane. While such gears are generally effective, the in-line arrangement occupies excessive space.
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.
SUMMARY OF THE INVENTION
The present inventions meet the above-stated needs and overcome the problems with prior cartridge loader systems.
A tape cartridge loader in accord with a first aspect of the invention includes a loader means for receiving the tape cartridge and moving the cartridge into operative engagement with a data tape drive in response to a linear actuation. The loader also includes a substantially flat actuator arm, for providing the linear actuation. The arm is mounted for pivotal motion, and it is coupled to the loader means, such that the pivotal motion of the actuator arm provides the necessary linear motion of the loader means. The actuator arm has a step-down sector gear, for rotating the actuator arm in response to a drive gear force applied through the sector gear.
The degree of offset of the sector gear with respect to the substantially flat arm preferably is the minimum needed to fit the arm, the sector gear and the associated drive gear into the minimal design envelope. The offset creates a moment of torque tending to twist the arm during actuation. The larger the offset, the higher this twisting torque moment.
In the preferred embodiment, the centerline of the teeth of the step-down gear is out of line from the central plane of the actuator arm. In fact, the offset may be such that the teeth of the sector gear do not cross the central plane of the actuator arm, and the teeth actually extend out beyond a surface plane, such as the lower surface, of the arm.
The disclosed embodiments also include a guide, for interaction with a distal end of the actuator arm during rotation of the arm, to limit any twisting due to the force moment caused by the offset of the sector gear relative to the arm. Preferably, the guide is a fixed member having a substantially flat section with a leading edge extending over the path of travel of the distal end of the actuator arm.
The preferred embodiments include a number of unique aspects relating to actuation by the sector gear and the arm. For example, the arm preferably includes a groove at a distance from its axis of rotation. The groove edges serve as cam profiles, to drive a bearing attached to the 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 includes an impact buffer spring, to bias the bearing within the groove.
The use of the flat actuator arm and cam follower further helps to minimize 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 t
Heinze Robert R.
Kim William B.
McDermitt, Will & Emery
Seagate Removable Storage Solutions LLC
Tupper Robert S.
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