Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Including threading
Reexamination Certificate
1999-04-16
2001-02-13
Rivera, William A. (Department: 3653)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Including threading
C242S338000, C242S334200, C242S357000, C242S333700
Reexamination Certificate
active
06186430
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to digital tape drive storage devices, and in particular, to the provision in a digital tape drive for determining when a tape cartridge is properly loaded, and more particularly, to a sensing assembly for determining the connection status between magnetic tape within the tape cartridge and a takeup reel within a digital tape drive employing a single reel.
PROBLEM
Digital data is stored on tape drives utilizing a variety of designs, but in all cases, magnetic tape media is wound between a pair of tape reels as data is transferred to or from the tape media. In the art of data storage, the physical space required to store data is an important concern. To conserve space, tape drives often use a single reel tape cartridge design, which utilizes a supply reel located within the tape cartridge and a takeup reel located within the tape drive. After the tape cartridge is inserted into the tape drive, the magnetic tape must be connected to the takeup reel. Various methods have been employed to make this connection. One such method connects the magnetic tape to the takeup reel via a buckle between a tape cartridge leader and a takeup leader as described in U.S. Pat. No. 4,572,460.
The magnetic tape within the tape cartridge is terminated at one end by the tape cartridge leader, which is a strong flexible plastic strip containing an ovular aperture on its distal end. The takeup leader is a similar strong flexible plastic strip attached at one end to the takeup reel. The other end has a stem and tab designed to buckle with the ovular aperture on the tape cartridge leader. When the tape cartridge is inserted into the tape drive, the takeup leader and tape cartridge leader are positioned to buckle together. This system improved on prior art systems employing a combination of vacuum and air pressure to guide the tape through a path, but still results in connection failures due to wear, misalignment or other causes.
In the prior art, connection failures are not always detected by the tape drive. If a connection fails, the takeup leader is free to be drawn into the tape path when the takeup reel is energized. Due to the flexible nature of the takeup leader, it cannot be pushed back out once it has been pulled in, thus rendering the tape drive inoperable. Fixing the tape drive requires removing the drive from its enclosure, disassembly of the drive, and repositioning of the takeup leader. This results in significant downtime and cost for users. In addition, because the connection mechanism wears out over time, the problem of connection failures is most common in high duty cycle applications, where it causes the most damage. For example, in applications such as library tape drive systems, a broken tape results in a load failure. The library then moves the bad tape to a new tape drive, which is in turn rendered inoperable. This process can repeat until the entire system is down.
For these reasons, it is desirable to have a sensing mechanism that detects connection failures and alerts an operator and/or system of the failure, while providing a method of recovery without the need for removal and disassembly of the tape drive unit.
SOLUTION
The present tape drive sensing assembly overcomes the problems outlined above and advances the art by preventing a connection failure in a single reel tape drive from rendering the tape drive inoperable. The sensing assembly prevents connection failures from rendering the tape drive inoperable by determining if magnetic tape within the tape cartridge is properly connected to the takeup reel in the tape drive. More particularly the sensing assembly detects whether the tape cartridge leader is properly connected to the takeup leader. The sensing assembly provides a method for automatically resetting the takeup leader if a connection fails. The sensing assembly comprises a microprocessor and at least one position sensor that detect various movements in the tape drive consistent with specific connection statuses, namely, proper connection and connection failure.
In a first embodiment, a takeup motor energizes the takeup reel to bias the takeup leader on a catch, while the supply reel is allowed to rotate freely. The catch holds the takeup leader as the connection is made. A load motor then rotates the catch from an unloaded position to a loaded position. The torque applied by the takeup motor holds the takeup leader on the catch during rotation of the catch. If the connection is successful, the tape cartridge leader is pulled slightly out of the freely rotating supply reel as the catch rotates. A position sensor detects the movement of the supply reel as a first confirmation of a good buckle. The supply reel is then energized slightly more than the takeup reel in the opposing direction so that the takeup leader is pulled back toward the supply reel and off of the catch. A second position sensor provides a second confirmation that the connection exists by sensing the reverse motion of the takeup leader as the supply reel pulls the takeup leader back and off the catch. If the connection is not confirmed, the takeup leader remains on the catch, and will not move until it is pulled back to the unloaded position with the catch.
In other embodiments, the supply reel is not free to rotate as the catch is rotated to the loaded position. If the connection is made, the takeup leader is held by the tape cartridge leader, and moves only slightly as it releases from the catch during rotation to the loaded position. If the connection is not made, the takeup leader remains on the catch as it rotates, moving the takeup leader further than if the connection was made. The additional movement in the takeup leader is sensed and used to indicate a connection failure. Because the takeup leader remains on the catch, it is not drawn into the drive by the takeup reel, and moves with the catch as it is returned to the unloaded position.
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Benchmark Tape Systems Corporation
Duft, Graziano & Forest, P.C.
Rivera William A.
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