Winding – tensioning – or guiding – Unwinding and rewinding a machine convertible information... – Including threading
Reexamination Certificate
2002-07-03
2004-11-09
Nguyen, John Q. (Department: 3654)
Winding, tensioning, or guiding
Unwinding and rewinding a machine convertible information...
Including threading
C242S332800, C360S095000
Reexamination Certificate
active
06814324
ABSTRACT:
FIELD OF THE INVENTION
The present invention broadly concerns methods and apparatus for storing and retrieving data on a tape medium. More specifically, the present invention concerns tape threading apparatus on tape transport apparatus. The invention particularly concerns a leader block that positively locks onto a leader pin of a tape transport medium. The invention also concerns a method of threading the tape medium through the tape transport apparatus using such a leader block.
BACKGROUND OF THE INVENTION
The advent of the computer has already had a profound effect upon human society, and the impact of processing technology is expected to increase. Indeed, the desirability to store information for subsequent retrieval currently grows at an exponential rate. Thus, various types of devices have been developed to store data both for on-line usage as well as for archival purposes.
Where on-line processing requires data to be readily at hand, a significant improvement was provided by the advent of the magnetic disk storage array. Here, one or more magnetic disks are provided, and a read/write recording head is used to record information on the disk as well as to retrieve information or data for use by the computer processor. Significant strides have been made in the ability to increase the density of data stored on such magnetic disk arrays. In order to gain an even higher density for on-line data, the optical disk was developed. These devices record data based upon a very small wavelength of light so that a higher density is obtained due to this technique. Laser light is employed to read the stored information or data on the optical disk.
In early days of the computer, before the advent of the magnetic disks and the optical disk storage assemblies, data was typically stored on magnetic tapes, such as reel-to-reel tapes and later cassettes. In a magnetic tape storage device, a magnetic coil is used as a transducer to imprint data magnetically on a moving band of magnetic film; thereafter, when the film is advanced across the transducer, the data may be read and re-input into a co-processor. Magnetic tape can be erased and rewritten many times and has an advantage of low cost.
Magnetic tape is still a highly desirable format for archiving data for rapid access is of less significance and cost is of concern. However, where vast quantities of data are to be maintained, these tapes can be bulky due to the physical number necessary to store the quantity of data. The capacity for such tapes to store data, of course, is dependent upon the number of “tracks” which can be independently placed across the width of the tape.
The ability to write data rapidly onto a magnetic tape film and the accessibility of data to be read from the film is a function of two variables: (1) the density of storage; and (2) the speed at which the tape medium may be transported across and accurately written/read by the transducer. Thus, for example, a magnetic tape read/write system that is able to read and write nine tracks of data on a single strip of tape will hold four and one-half times the amount of data as a system which only utilizes two tracks. Therefore, efforts to increase the capacity of magnetic tapes to store data have included substantial efforts to increase the number of tracks which can be written on a band of magnetic tape.
In the above-described systems, storage reels of tape, whether flanged or flange-less (for example as used in cartridges) may be placed on the machine during use. A threading assembly engages the free end of the tape and passes it through the machine. Typically, the tape is threaded across air bearings, past the transducer and into a take-up hub or reel. The length of the tape is then passed through the machine so that information may be placed on the tape or retrieved therefrom. During this process, the length of tape is transferred onto a take-up reel or hub that is either a part of the machine itself, included within the cartridge or that is mounted and de-mounted from such machine. After being transported through the machine, the tape may be rewound onto the storage reel and removed from the machine.
As was explained in my earlier U.S. Pat. No. 5,777,823, issued Jul. 7, 1998, it is important that the lateral edge of the tape moving in a transport direction be properly registered along a reference plane, called the datum, so that the data may be accurately input and retrieved from the tape medium. Support of the tape during transport is therefore critical, and typically employs guide rollers, air bearing and the like as is known in the art. Improved air bearings are the subject of U.S. Pat. No. 5,777,823 and U.S. patent application Ser. No. 10/111,728 filed Apr. 26, 2002 (priority date Oct. 28, 1999), the disclosures of which are hereby incorporated by reference. It is also important that the read/write head be accurately positionable. A representative structure for such positioning is shown in U.S. Pat. No. 6,078,478, the disclosure of which is hereby incorporated by reference.
Take-up reels are typically constructed to have a central hub that has annular flanges and a width slightly greater than the width of the tape. It is also known to use flange-less hubs in winding tape media. In either case, the hub is rotated about a central winding axis, and the length of tape is wrapped circumferentially around the hub.
Many tape drives utilize a tape source in the form of a cartridge which may be mounted or demounted into the recording and reading apparatus. These cartridges typically contain a spool of tape media upon which information may be stored. The tape media is then transported across the read/write recording head either to place data on a blank tape which you override existing data, as is the case with a “write” operation or, alternatively, to retrieve information that already exist on the tape media during the “read” state. In either case, the tape is typically attached to a leader pin that is adapted to be engaged by a leader block that is part of the threading mechanism. The threading mechanism engages the leader pin by means of the leader block, and then mechanically threads the tape across air bearings that ore disposed on either side of read/write recording head. The threading mechanism conveys the leader block to a take-up hub.
Traditional leader blocks engage the leader pin of a tape medium from the side, that is, laterally. Thus, traditional leader blocks rely upon constant tension of the tape medium in order to maintain an engaged relationship. This presents a problem in several respects. On one hand, if the leader pin is improperly parked in the tape cartridge, the leader block may not even be able to engage the leader pin to withdraw the tape from the cartridge. In the event that the leader block does engage the leader pin and begins to pull the tape from the cartridge, misregistration of the leader pin in the leader block can result in the leader block's dropping the leader pin during the threading operation. Once the leader pin is lost, it cannot be recovered by the threading apparatus so that the equipment must be serviced or repaired. Not only is this expensive in cost due to the cost of repairs and down time, the lost leader pin can damage the read/write apparatus.
Even where the leader block properly engages the leader pin, there is still always the risk that some other event will cause a release of tension on the tape medium. For example, if a power outage occurs, tension is lost and the leader pin can fall out of the leader block. This results in the same issues of repair and damage noted above.
Accordingly, there is a need for an improved leader block assembly which can selectively releaseably engage the leader pin in a positive manner. There is need for a leader block that can positively engage the leader pin for virtually all types of threading assemblies and for the use of such a leader block in a tape transport apparatus. The present invention is directed to meeting these needs.
SUMMARY OF THE INVENTION
It is an object of the present in
Gavit Stephan E.
Goldsmith Christopher D.
Gegick Rebecca A.
Henson Michael R.
Martin Timothy J.
Nguyen John Q.
Segway Systems, LLC
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