Dynamic magnetic information storage or retrieval – Record medium – In container
Reexamination Certificate
1999-11-19
2001-09-11
Evans, Jefferson (Department: 2652)
Dynamic magnetic information storage or retrieval
Record medium
In container
C360S130330, C242S346000
Reexamination Certificate
active
06288872
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to magnetic tape cartridges. More particularly, this invention relates to a spring structure, referred to as a “lifter,” which maintains contact between a read/write device and the magnetic tape in a tape cartridge.
BACKGROUND OF THE INVENTION
Magnetic tape cartridges are widely used for data storage. A conventional magnetic tape cartridge comprises reel mounts on which tape reels are held in place. A magnetic tape is attached to two tape reels, and is wound around one or both of the reels. The reels are rotatable on the reel mounts, allowing the reels to transfer the commonly attached magnetic tape from one reel to the other upon rotation. A portion of the tape is exposed to the outside of the cartridge by means of an open bay portion which may comprise a door or other protective lid-type feature for protection of the tape when the cartridge is not in use.
When in use, the bay portion of the cartridge receives an external read/write device which sends information to be recorded onto a tape, or retrieves recorded information from the tape. The read/write device accomplishes this by entering the bay portion, and contacting the tape.
As the tape extends across the bay portion of the cartridge, and is moved from one reel to the other, the tension in the tape is the greatest when each reel is holding equal amounts of tape. However, when any one reel is holding more or less tape than the other reel, the tension in the tape can become insufficient for enabling continuous physical contact between the tape and the read/write device. This lack of tension in the tape, and in turn, lack of physical contact between the tape and the read/write device, causes the transfer of information between the two elements to fail. As a result, some or all of the information intended to be transferred will be missing upon playback or subsequent transferring of information.
Accordingly, there is a need to provide a magnetic tape cartridge which includes means for maintaining a desired level of tension in the magnetic tape, sufficient to enable complete and direct contact between a read/write device and the magnetic tape, thus ensuring accurate and complete transfer of information between the two elements.
There is also a need in the art for means for maintaining a desired range of tension in tapes included in existing magnetic tape cartridges which otherwise fail to transmit information between the tape and the read/write device. The range of tension should be sufficient to enable complete and direct contact between the read/write device and the magnetic tape, thus ensuring accurate and complete transfer of information between the two elements.
SUMMARY OF THE INVENTION
It is an object of the invention to meet the aforementioned needs. In fulfillment of this object, a magnetic tape cartridge having a lifter device is provided according to the present invention. The lifter device bends upward from a surface of the bay portion of the cartridge, beneath the exposed portion of the tape. The lifter device maintains a desired range of tension in the tape when the tape and the lifter device are in contact. This in turn maintains a sufficient amount of pressure between the read/write member and the tape.
It is a further object of the invention to provide a resilient, flexible, relatively rigid lifter device which will provide the desired tension in the magnetic tape over a wide range of temperatures which the cartridge may be subjected to during the normal course of operation. This object is accomplished by providing a lifter device which comprises a resilient, flexible, relatively rigid plastic sheeting, such as polyethylene terephthalate (PET) or teflon.
It is another object of the present invention to provide a lifter device which can be easily introduced into existing magnetic tape cartridges, to provide a desired range of tension in the magnetic tape. This object is accomplished by providing a lifter device which comprises a resilient, flexible, relatively rigid plastic sheeting, such as polyethylene terephthalate (PET) or teflon, which may be attached to the existing magnetic tape cartridge with an adhesive, and which bends upward from a surface of the bay portion of the cartridge beneath the exposed portion of the tape. The lifter device maintains a desired range of tension in the tape when the tape and the lifter device are in contact. This in turn maintains a sufficient amount of pressure between the read/write member and the tape to maintain contact between them.
Another object of the invention is to provide a method for maintaining contact between a magnetic tape in a tape cartridge and an external read/write device, including the steps of providing a bay portion in the tape cartridge wherein the tape is exposed outside the tape cartridge, providing a lifter device, and attaching the lifter device on a surface of the bay portion in a manner wherein the lifter device provides a sufficient range of tension in the tape to maintain said contact. As described above, the lifter device may be made from a resilient, flexible, heat resistant material such as polyethylene terephthalate (PET) or teflon.
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Evans Jefferson
Kananen Ronald P.
Rader Fishman & Grauer
Sony Corporation
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