Dynamic magnetic information storage or retrieval – Record transport with head stationary during transducing – Tape record
Reexamination Certificate
2002-05-14
2003-02-04
Tupper, Robert S. (Department: 2652)
Dynamic magnetic information storage or retrieval
Record transport with head stationary during transducing
Tape record
Reexamination Certificate
active
06515823
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a technique for opening an access door of a data tape cartridge. The invention also relates to a loader mechanism incorporating the door opening device, for example, a mechanism for loading a single-reel magnetic tape cartridge into 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.
A number of manufacturers have recently developed a new format based on a linear tape-open technology. This technology accommodates a range of storage requirements from single server to complex network environments, in both fast-access and high-capacity formats.
Of particular note, the high capacity tape format uses a single reel cartridge to maximize capacity, for example, for backup, restore, and archive applications. The high-capacity linear tape-open format uses a new data cartridge designed to maximize the amount of tape surface area while still enabling use of very small form factors. Present implementations of this cartridge contain 600 meters of half-inch tape and have a native storage capacity of 100 GB. The form factor for this tape cartridge is 105.4 mm wide, by 102 mm long by 21.5 mm high.
The drive mechanism for the linear tape-open high-capacity tape cartridge provides bi-directional tape motion during read/write and locate/rewind operations. The single-reel cartridge design uses a take-up reel located inside the drive. A coupler grabs a leader pin at the start of the tape and draws it out of the cartridge and around the tape head to the take-up reel in the drive. After the leader pin is secured in the take-up reel, the reel rotates and pulls the tape through the tape path. A gear built into the cartridge reel and a gear coupled to the drive reel motor form a clutch enabling the motor to drive the rotation of the tape reel within the cartridge.
A cartridge of the size used for the high-capacity for the linear tape-open format or a similarly sized competing cartridge product, by itself fills a substantial portion of the design envelope for the tape drive. In the past, tape drives for cartridges of such size 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 an operator to grip and remove the cartridge.
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 mechanisms, 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 it 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.
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.
Most data tape cartridges in use today have an access door. The door normally is closed, to protect the tape media and any data stored thereon. The automatic loader for the tape drive therefore must include some mechanism that opens the access door during loading of the cartridge. A wide variety of different access-door opening mechanisms have been tried in the past. To a large extent, these mechanisms have reflected the particular structure and operation of the access door of the tape cartridge.
A number of available cartridge designs, including designs for single-reel cartridges, have used hinged doors. The opening mechanism for such a cartridge must swing the door open and into an unobtrusive position before the front of the tape cartridge gets too near the read/write head(s).
For example, U.S. Pat. No. 5,868,333 to Nayak discloses a single-reel tape cartridge design with a hinged access door, wherein the cartridge incorporates a cable and tab arrangement that serves as part of the door opening mechanism. A finger mounted in the tape drive engages the tab, to apply force through the cable to a reel around the pivot pin of the access door and pivot the door open, as the cartridge is inserted into the drive. This configuration does permit opening of the aperture door without the need for motors or electrical components.
U.S. Pat. No. 5,237,469 discloses a door opening mechanism for use in an automatic cartridge loader. This mechanism, however, utilizes a complex ratchet gear, pivot pin and lever arm arrangement. Such a mechanism requires a large number of parts, making it expensive. Because of the complexity, it would likely serve for only a relatively small number of operation cycles. Also, such a mechanism takes up considerable real estate within the design envelope of the drive.
U.S. Pat. No. 5,495,374 also discloses an automatic tape cartridge loader. This Patent suggests the use of a door opening mechanism that includes a pivotable arm with a pin that engages a slot in the tape access door. The arm pivots the tape access door at the forward end of the cartridge to open the door and expose a segment of the tape, as the cartridge is inserted into a carriage of the loader. After the door is open, the carriage assembly is automatically moved forward to carry the cartridge forward and engage the exposed segment of the tape in the cartridge with a head.
The automatic tape cartridge loader disclosed in U.S. Pat. No. 5,331,485 utilizes a spring loaded pivot member to engage and open the access door. As the cartridge support carriage moves inward, a stud follows an angled cam surface to allow the pivoting member to pivot under the force of a spring. The pivoting member includes a finger, which engages the rear extension of the access door as the pivoting member
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pivots, to thereby push the access door open.
U.S. Pat. No. 5,543,993 discloses a door opening mechanism using a pin to engage a s
McDermott & Will & Emery
Seagate Removable Storage Solutions LLC
Tupper Robert S.
LandOfFree
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