Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/008—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires
  • G11B5/00813—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires magnetic tapes
  • G11B5/00847—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires magnetic tapes on transverse tracks
  • G11B5/0086—Recording on, or reproducing or erasing from, magnetic tapes, sheets, e.g. cards, or wires magnetic tapes on transverse tracks using cyclically driven heads providing segmented tracks
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
  • G11B15/60—Guiding record carrier
  • G11B15/61—Guiding record carrier on drum, e.g. drum containing rotating heads
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
  • G11B15/60—Guiding record carrier
  • G11B15/61—Guiding record carrier on drum, e.g. drum containing rotating heads
  • G11B15/615—Guiding record carrier on drum, e.g. drum containing rotating heads inside container
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
  • G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means
  • G11B23/04—Magazines; Cassettes for webs or filaments
  • G11B23/08—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends
  • G11B23/087—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends using two different reels or cores
  • G11B23/08707—Details
  • G11B23/08757—Guiding means
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B23/00—Record carriers not specific to the method of recording or reproducing; Accessories, e.g. containers, specially adapted for co-operation with the recording or reproducing apparatus ; Intermediate mediums; Apparatus or processes specially adapted for their manufacture
  • G11B23/02—Containers; Storing means both adapted to cooperate with the recording or reproducing means
  • G11B23/04—Magazines; Cassettes for webs or filaments
  • G11B23/08—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends
  • G11B23/087—Magazines; Cassettes for webs or filaments for housing webs or filaments having two distinct ends using two different reels or cores
  • G11B23/08707—Details
  • G11B23/08778—Driving features, e.g. belt
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
  • G11B5/52—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with simultaneous movement of head and record carrier, e.g. rotation of head
  • G11B5/53—Disposition or mounting of heads on rotating support
  • G11B5/531—Disposition of more than one recording or reproducing head on support rotating cyclically around an axis
  • G11B5/535—Disposition of more than one recording or reproducing head on support rotating cyclically around an axis perpendicular to the direction of movement of the tape, e.g. for longitudinal scanning
  • G11B5/537—Disposition of more than one recording or reproducing head on support rotating cyclically around an axis perpendicular to the direction of movement of the tape, e.g. for longitudinal scanning with all the heads disposed in a plane substantially parallel to the plane of the tape, e.g. for circular scanning
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
  • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
  • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
  • G11B5/584—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes
  • G11B5/588—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for track following on tapes by controlling the position of the rotating heads

Definitions

• the present invention relates to arcuate scanning head assemblies, and in particular to mechanisms for improving the tape- head interface.
• Tape drives conventionally have used either a fixed head (often used on audio and computer data tapes) or a Vertical Helical Scan (VHS) head (often used on video tapes and sometimes on computer data tapes).
• VHS Vertical Helical Scan
• a fixed head the head stays still, and the tape moves linearly past it.
• VHS head one or more heads are located on the outside of a rotating cylinder or drum. The tape moves past the side of the cylinder, wrapping slightly around the cylinder as it does. The cylinder is angled, so that the path of each head along the tape is a helix. In both of these conventional designs, contact between the head(s) and the tape can be maintained simply by having the tape wrap part way around the head or drum.
• ASHA Arcuate Scanning Head Assembly
• a VHS drive an ASHA 20 has magnetic heads 21 mounted to a cylinder 22 (see Figs. 1A, 1 B), which rotates in the direction of arrow 23.
• the heads 21 are mounted to the end 24 of the cylinder 22 rather than the side 26, and the end 24 is in a_plane parallel to the plane of the tape 28.
• the heads 21 protrude slightly from the end 24 of the cylinder 22, so they come into contact with the tape 28 as it moves past the ASHA in the direction of the arrow 29.
• the cylinder 22 rotates at very high speeds, e.g., 15,000 RPM, so the path of each head 21 across the tape 28 is essentially an arc. While just one head could be used, typically a plurality of heads would be preferable to increase the density of the tracks on the tape, e.g., eight heads as shown in the drawings.
• the ASHA 20 includes a vacuum tube, shown schematically at 34, to pull the tape 28 down onto the heads 21.
• the ASHA makes contact with the tape 28 as shown schematically in Fig. 1 C.
• the vacuum tube 34 pulls the tape down most strongly at 36, corresponding to the center of the ASHA 20, while the heads 21 push the tape up at 38, 40, corresponding to the paths of the heads 21 on the front side 30 and back side 32 of the ASHA, respectively.
• the heads 21 strike the edge of the tape 28 at locations 44 and 46 each time they rotate.
• This striking of the tape edge could result in high wear on the tape 28.
• the present invention tilts the ASHA by a slight angle ⁇ relative to the plane of the tape along the center axis of the tape.
• the heads are either completely out of contact with the tape on the back side of the cylinder, or make only slight contact.
• the problems of contact between the back side heads and the tape are eliminated or substantially reduced by doing this.
• the tape since the tape is no longer subjected to significant twisting forces due to heads moving past it in both directions, it can be wrapped slightly around the front side heads to improve head to tape contact. Of course, the greater the degree of wrapping, the larger the angle ⁇ must be to avoid problems.
• angling the ASHA also eliminates or reduces problems with the heads striking the edge of the tape.
• the heads move up into and then down out of the plane of the tape as the ASHA cylinder rotates.
• the heads simply are not in the plane of the tape when they are positioned below the tape edge, so they do not make contact with it. They then make initial contact some distance ⁇ in from the edge of the tape as they move up into the plane of the tape, completely eliminating the problem of striking the edge.
• the distance ⁇ increases as the angle ⁇ is increased.
• the heads will just graze the edge, but the problem will be significantly diminished.
• An alternative embodiment of the present invention is to leave the ASHA straight, but change the angle of presentation of the tape by the tape cartridge so that instead of running straight across the media access opening of the tape cartridge, the tape is presented at an angle ⁇ .
• the net effects of changing the tape presentation angle within the cartridge are substantially the same as those from changing the ASHA angle, since the relative geometry of the tape and ASHA are the same in either embodiment.
• angling the tape instead of the ASHA may allow a simpler design for the tape drive, since the ASHA can be positioned perpendicular to the face of the cartridge.
• FIG. 1 A is a schematic front view of a prior art ASHA with a tape moving past it.
• Fig. 1B is a schematic bottom view of the device of Fig. 1 A.
• Fig. 1 C is a schematic representation of the deformation effects on the tape of the prior art ASHA of Fig. 1 A.
• Fig. 2A is a schematic front view of an angled ASHA according to the present invention with a tape moving past it.
• Fig. 2B is a schematic top view of the device of Fig. 2A.
• Fig. 2C is a schematic representation of the deformation effects on the tape of the ASHA of Fig. 2A according to the present invention.
• Fig. 2D is a schematic view of a tape cartridge with a conventional straight tape presentation used with the angled ASHA of Fig. 2A.
• Fig. 3 is a schematic representation of an alternative embodiment of the invention in which the ASHA is left perpendicular to the front face of the cartridge, but the tape cartridge presents the tape at an angle.
• FIGs. 2A, 2B the structure and function of the cylinder 122, heads 121 and the like are substantially the same as the prior art ASHA 20 described above.
• Features substantially the same as in ASHA 20 therefore have been labeled in the figures with the same reference numerals with the addition of 100, and will not be described further here.
• the absolute sizes of the head protrusion, the angle ⁇ , and the resultant tape deformation have been grossly exaggerated in all of the drawings for clarity of explanation.
• the ASHA 120 differs from the prior art ASHA 20 in that it is angled relative to the plane of the tape 128 by an angle ⁇ between the center line of the ASHA 120 and a line perpendicular to the tape 128.
• angle ⁇ between the center line of the ASHA 120 and a line perpendicular to the tape 128.
• relative sizes of the angle ⁇ , the diameter of the cylinder 122 and how much the heads 121 protrude from the end face 124 of the cylinder 122 will control the degree to which the heads 121 contact the tape 128 on the back side 132 of the ASHA 120.
• the relative sizes are such that the heads 121 do not make contact with the tape 128 on their return path along the back side 132 of the ASHA 120.
• the relative sizes can allow minimal contact. Largely due to the angling, the tape 128 itself wraps slightly around the heads 121 on the front side 130 of the ASHA 120 .
• Fig. 2C illustrates the effects of the ASHA 120 on the tape 128.
• the heads 121 push the tape up along the path 150 corresponding to the path of the head when it is on the front side 130 of the ASHA 120.
• the path 150 differs from path 38 because it does not extend all the way to the edges of the tape 128.
• each head 121 moves up into, then down out of the plane of the tape 128. As it does this, it first makes contact with the tape 128 some distance ⁇ -
• the exact size of the distances ⁇ * * and ⁇ will depend upon the relative sizes of the angle ⁇ , the width of the tape 128, the diameter of the cylinder 122 and the degree to which the heads 121 protrude from the cylinder end face 124. It also will be apparent that the relative sizes of distances ⁇ -j and ⁇ will depend upon whether the tape is centered about the center line of the cylinder 122. Under most circumstances, the tape preferably will be centered, so that the distances ⁇ * * and 82 will be substantially equal.
• Fig. 2C assumes that sizes of the heads 121 , angle ⁇ and the diameter of cylinder 122 are such that there is no contact between the heads 121 and the tape 128 on the back side 132 of the ASHA 120. As a result, there is no deformation of the tape along the back side 132 of the ASHA 120 to correspond to the path 40 with the prior art ASHA 20. If the dimensions were such that there was some minimal contact between the heads 121 and the tape 128, there would be a path analogous to path 40. However, this path also would contact only part of the tape 128, near the edges, as the heads 121 moved into and out of the plane of the tape 128.
• FIG. 2C shows no dimpling around the vacuum tube 134. Such dimpling is substantially eliminated since the end of the vacuum tube 134 is not in contact with the tape 128. Indeed, while a vacuum tube 134 is shown in Figs. 2A, 2B, it may well be possible to eliminate it entirely with the present ASHA 120.
• the ASHA cylinder 120 might be 1.77 ⁇ .05 cm in diameter and the heads 121 might protrude.02 ⁇ .005 mm above the cylinder end face 124.
• an angle of just 2/3 degrees would be sufficient to prevent the heads 121 from contacting the tape 128 on the back side 132 of the cylinder 122, though an angle of about 2 degrees might be preferable to ensure there is no contact.
• Fig. 2D illustrates a tape cartridge 160 with a conventional straight line presentation of the tape 128, shown positioned for use with the angled ASHA 120 just described.
• guide rollers or pins 162, 164 typically are positioned to present the tape 128 in a straight line across the media access opening 168 of the tape cartridge 160.
• the small angling of the ASHA 120 in the first embodiment generally may be expected to have little effect on other elements, e.g., the positioning mechanism, of the drive (shown schematically in Fig. 2B as 155) in which the ASHA 120 is mounted, while having a large impact on the tape to head interface.
• the present invention therefore can very easily be adapted for use with prior ASHA drive designs.
• the alternative embodiment shown in Fig. 3 may be useful in those situations where even limited angling of the ASHA 120 is difficult, e.g., due to space considerations in the drive.
• an ASHA 20 is shown conventionally positioned with its axis perpendicular to the tape cartridge 170.
• the cartridge 170 includes the usual baseplate 172 and front face 174, with a reference plane defined proximate the front face 174 and perpendicular to the baseplate 172 (i.e., proximate the front face 174 and perpendicular to the plane of the drawing) for accurate positioning of the cartridge with respect to the reference plane of the drive.
• the guide pin or roller 175 has been shifted relative to the guide pin or roller 176 so that the tape 178 is presented at an angle ⁇ across the media access opening 179.
• the net effect is the same as in the first embodiment -- the ASHA 20 makes contact with the tape 178 at an angle ⁇ . It will be noted that with the geometry shown in Fig.

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• Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=23013312

Family Applications (1)

Country Status (4)

Cited By (6)

Citations (4)

• 1995
  • 1995-06-15 CN CN 95193800 patent/CN1151220A/zh active Pending
  • 1995-06-15 WO PCT/US1995/007681 patent/WO1996000437A1/en not_active Application Discontinuation
  • 1995-06-15 JP JP8503242A patent/JPH10502478A/ja active Pending
  • 1995-06-15 EP EP95923931A patent/EP0767951A1/en not_active Withdrawn

Patent Citations (4)

Non-Patent Citations (2)

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