US3773983A - Lateral strip control apparatus - Google Patents

Lateral strip control apparatus Download PDF

Info

Publication number
US3773983A
US3773983A US00260602A US3773983DA US3773983A US 3773983 A US3773983 A US 3773983A US 00260602 A US00260602 A US 00260602A US 3773983D A US3773983D A US 3773983DA US 3773983 A US3773983 A US 3773983A
Authority
US
United States
Prior art keywords
strip
guide bar
bars
guide
frame
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00260602A
Other languages
English (en)
Inventor
D Larson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Control Data Corp
Original Assignee
Control Data Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Control Data Corp filed Critical Control Data Corp
Application granted granted Critical
Publication of US3773983A publication Critical patent/US3773983A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • G11B5/48—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
    • 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
    • G11B15/602—Guiding record carrier for track selection, acquisition or following
    • 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

Definitions

  • ABSTRACT Apparatus for transversely moving and positioning a segment of a flexible magnetizeable strip to permit access to a specified one of a plurality of data tracks thereon by a data transducer.
  • the transducer is mounted in a rotating drum partially encircled by the strip and the strip segment is transversely moved by two pairs of parallel bars or cylinders through which the strip runs. In each pair, the strip partially encircles each bar in opposite directions by passing between them. By angling the pairs of bars with respect to the strip itself the portion of the strip between the pairs of bars may be caused to move to desired transverse positions.
  • Field of the Invention involves apparatus for mass storage of data which is automatically retrievable under computer or other control.
  • this invention relates to devices having as the storage medium a recording surface such as iron oxide, and transducers for reading and writing information on the surface, which moves relative to the transducers. This definition of the field is probably the most important, since it includes the devices which will be the competitors of this invention in the market place. In-
  • disc and drum memories noted more for their capacity than their access speed although data rates, once the desired physical area is addressed, may be quite high. More narrowly still, the field relates to such devices having a flexible, magnetizeable surface on which the reading and writing occurs.
  • the essence of this invention is apparatus which performs the multiple track addressing by shifting the strip relative to the head path more effectively and efficiently than heretofor has been possible. It borrows a technique which has long been used in controlling webs, such as paper, polyethelene film, and cloth.
  • Such devices are described in, among other references, U. S. Pat. Nos. 2,7 l6,026, Axworthy; 2,797,091, Fife; and 3,024,955, Powers.
  • Each of these patents describe variations ofa device common to all of them, a pair of parallel guide rollers over which the web passes in a particular way, viz. between the rollers and partially encircling each.
  • the position of the exiting web can be changed with respect to that of the web entering the guide rollers.
  • the rollers may be set at an angle to web motion and the transverse web position varied by varying the distance between the pair of rollers.
  • This invention utilizes a rotating drum or other means to support a conventional data transducer adja:
  • the transducer may be embedded within the curved surface of the drum with its transcribing surface facing outwardly therefrom.
  • a flexible strip having a plurality of recording tracks may then be used as the recording medium.
  • the strip partially encircles the drum and is supported by an air bearing interface thereon.
  • the circle described by the transcribing surface of the data transducer traces out a data track when adjacent the strip surface encircling the drum.
  • both pairs of rollers are pivoted so as to cause the strip section between them to be shifted toward a desired end of the drum, a second track on the strip may be accessed by the data transducer.
  • the shifted portion will remain parallel to the unshifted part, and tension across the width of the strip will be uniform, preventing asymetrical stretching or scalloping of the strip.
  • the data transducer may be made to access a plurality of adjacent and closely spaced recording tracks.
  • Various means may be used to tension the strip to keep the strip positioned properly and sufficiently close to the transducer to permit transcription of data.
  • each roller a cylinder or bar having a curved convex surface encircled by the strip and provided with means for creating an air bearing contact between the strip and the guide cylinder surface encircled by the strip.
  • An air bearing interface between the strip and a bar reduces friction to very nearly zero between them.
  • the strip need not be short, but may be made as long as several thousand feet.
  • the length of strip not in current use may be stored on a pair of take-up spools which can be rotated when it is desirable to present a fresh surface with a new set of tracks for accessing to the drum. Widths up to 60 cm. may be easily accommodated.
  • the guide bars may .be hollow, and hence of low mass.
  • Low mass means low acceleration forces when pivoting them.
  • the section of the strip transversely accelerated is also of very low mass.
  • Both the strip and the guide bars move but a short distance, a matter of a very few inches at the most. For all these reasons, a new track may be accessed very rapidly.
  • the conventional method of accessing a new track involves either moving the drum, the heads or the strip ends themselves.
  • FIG. 1 is a left side perspective view of a simplified embodiment of the invention.
  • FIG. 2 is a right side perspective view of a fully useable eembodiment of the invention.
  • FIG. 3 is a cross-sectional view of the strip position control system of FIG. 2 and a block diagram of the control electronics.
  • FIG. 4 is a top view of the apparatus of FIG. 2.
  • FIG. 5 is an alternative embodiment of the apparatus, employing a different means of shifting strip position on the drum.
  • FIG. 6 is a cross-sectional view of the drum surface showing the arrangement of a transducer head.
  • FIGS. 70 and 7b display the means for creating an air bearing contact between a bar and the strip.
  • FIGS. 9a and 9b are orthogonal views of the strip passing over a pair of guide bars and display the dimensions which determine the amount of strip offset.
  • FIG. 8 displays an alternative means for mounting and pivoting a pair of guide bars.
  • FIG. 10 displays a block diagram of the strip position control system.
  • FIGS. 1 and 2 shown therein is a frame 100 on which, or relative to which, are located all the essential mechanical components of this invention.
  • the outside housing of motor 103 is attached to frame 100.
  • Drum 101 mounted on the output shaft of motor 103 and rotated thereby, may be supported at the right, or free end by a bearing 240 not shown for clarity in FIG. 1.
  • Data transducer head 111 is embedded within and held by drum 101 with its transcribing surface facing outwardly from the surface of drum 101,
  • FIG. 6 The dotted lines labeled 111 in FIG. 2 indicate position of the heads when a plurality of them are employed.
  • Guide bar holders 104a and 104k are pivotably attached to frame 100 by pivots 122a and 122b.
  • Held rigidly with respect to each other by holder 104a are a pair of guide bars 105a and 106a, the surface of each comprising a convexly cylindrical surface.
  • plane i.e., the plane perpendicular to the axis of drum 101, are controlled by solenoids or voice coils 114a and 114b, setting the angular position of assemblies 121a and 1211) respectively.
  • Voice coils 114a and 114k are pivotally attached to frame by members 118a and 1l8b respectively.
  • the surfaces perpendicular to the axis of rotation of holder pivots 122a and 122b must be planes perpendicular to the vertical plane and for convenience. will be referred to as horizontal planes (although those associated with pivot 122a need not be parallel to the apparent horizontal plane of FIGS. 1 and 2 or to those of pivot 122b, and vice versa).
  • Voice coil 114b has a sliding armature 115b attached by pivot 124b to bracket 116b, which is in turn attached to the end of bars and 106b.
  • armature llSb varies the angular position of bars 105b and 106b with respect to the vertical plane.
  • the position of armature llSb is controlled by voice coil input 119b, shown in FIG. 2 as supplied by control unit 205.
  • voice coil input 119b shown in FIG. 2 as supplied by control unit 205.
  • voice coil 114a A similar arrangement is made for voice coil 114a and the elements associated with it.
  • Strip 102 is the actual recording medium on which data is transcribed by data transducer head 111.
  • the ends of strip 102 are held with respect to frame 100 by means allowing little or no movement of them perpendicular to the vertical plane while permitting slight extensions of strip 102 to accommodate variations in the length of its path as supports 104a and 104b are pivoted. By allowing slight extension of the strip at least at one end, more uniform tension may be maintained as the length of the path of strip 102 varies.
  • strip 102 has parallel edges, is symmetrical, or uniform, in cross section, and is of material of uniform modulus of elasticity, although these conditions are not necessary for operation of.the device. In FIG.
  • the holder of the near end of strip 102 comprises a simple clamp or bracket ll3b attached by springs 112 to frame 100.
  • the far end of strip 102 may be rigidly attached to frame 100 by a similar bracket 113a (not visible).
  • Each bracket clamps its end of strip 102 across the entire width of the strip to insure uniform tension across the width, thereby preventing skewing and curling of the strip.
  • FIG. 2 displays an alternative embodiment comprising capstans or spools-208a and 208b on which portions of strip 102 not in current use may be stored pending the need to transcribe data onto surfaces of the strip stored on spools 208a or 208b.
  • strip 102 tension is great enough to form flat surfaces or segments where strip 102 passes between the various bars.
  • Each segment has its own reference number designation.
  • Strip 102 partially encircles the convex cylindrical surface of guide bar 106b, passes between guide bars l05b and 106b forming segment 102a, and partially encircles the convex cylindrical surface of bar 105b.
  • the path of strip 102 further extends from bar 105b and around idler bar b, passing between it and drum 101 and forming strip segment 102d.
  • the part of bar 1 10b encircled by strip 102 is a part of a convex cylindrical surface of bar 110b, whose axis is parallel to that of drum 10. Part of segment 102a of strip 102 encircles drum 101, as shown.
  • strip 102 is seen to pass between drum 101 and idler bar 110a and partially encircle idler bar 1 10a, whose encircled surface is, as with idler 110b, convexly cylindrical with its axis parallel to the axis of drum 101.
  • the strip further extends to form flat segment 102f by partially encircling guide bar 105a, passing between it and guide bar 106a (FIG. 2). It partially encircles bar 106a, and passes over idler bar 202a to takeup spool 208a, forming strip segments 1023, 102k and 102i respectively as shown.
  • Bars 105a, 106a and 202a all have smooth, convexly cylindrical surfaces where encircled by strip 102.
  • Takeup spools 208a and 208b store that portion of strip 102 not containing tracks needed for immediate addressing by heads 111.
  • Idler bars 202a and 20212 are needed when takeup spools such as 208a and 208b are used. Thus, neither idler bar 202a or 20212 are present in the embodiment of FIG. 1.
  • strip segments 102b and 102d both are parallel to the horizontal plane associated with guide bar assembly 121b.
  • strip segments l02f and 10211 are parallel to the horizontal plane associated with assembly 121a.
  • the axial or lateral position of strip 102 with respect to head 111 is accurately measured and the measurement is employed in feedback apparatus to precisely position strip 102 on drum
  • Strip position is determined by position of strip edge sensor 220 which is carried by arm 218, slidably attached to and moved by voice coil 219 in turn attached to frame 100.
  • no edge sensor is used. Instead, it is assumed that individual tracks are spaced apart sufficiently to permit individual track addressing by merely placing the angular position of guide bar assemblies 121a and 121b at preset orientations.
  • data is transmitted to and received from heads 111 via slip rings 117.
  • slip rings 117 may be mechanical, employing brushes, or operate inductively.
  • the stationary elementof the slip rings may be connected via a conductor (not shown) to a central computer or other data processing device.
  • the moving element of each slip ring 117 may be connected to a single head Ill.
  • switching circuitry may be included within drum 101 to multiplex several heads 111 into one slip ring 117.
  • drum 101 In operation, power supplied to motor 103 causes drum 101 to spin at a speed causing the exterior surface of the drum to have a circumferential speed around 2,500 in/sec. This speed permits short access time and high data rate and also creates a natural foil or air bearing clearance between strip 102e and drum 101.
  • the curved surface of drum 101 may be provided with holes through which air is forced. thereby creating an air bearing interface if lower speeds are used.
  • the guide and idler bars may be mounted to rotate aboutthelr longitudinal axes. Preferably, however, they are non-rotating, and have holes 703 (FIGS. 74 and 7b) placed 5 interior to the lines. of tangency of strip 102 on the surface encircled by strip 102. Compressed air is forced through these holes, thereby creating the air bearing interface between strip 102 and the surfaces with respect to which it may slide.
  • a track on strip 102 can be specified in terms of the angular position of the assemblies 121a and 1211).
  • the angular position for guide bar assembly 121b will be measured in the horizontal plane containing the axis of the convex cylindrical surface of bar 106b clockwise from the vertical plane to this axis. This angle will be referred to as angle B.
  • angle A the equivalent angle
  • angle A the equivalent angle
  • Strip segment 102e may be placed at any position along the entire length of drum 101 properly setting angles A and B. However oriented, it is important that these angles be equal. In the position shown in FIG. 1, these angles are near a minimum and segment 102e is nearly as far to the right on drum 101 as possible. If strip 101 is bilaterally symmetrical, or uniform, in cross section and has uniform modulus of elasticity a single equilibrium position of segment 102e exists for any specific angle assumed by assemblies 121a and 121b. If strip segment 102e is not at the equilibrium position for the values of angles A and B, unequal tension in strip 102 exists caused by differences in the path length across the width of strip 102. This creates lateral forces which tend to shift segment 102e to the equilibrium position.
  • FIGS. and 9b Shown therein is a part of guide bars 10512 and 106b over which an edge of strip 102 is shown wrapped. For' ease in analysis, bars 106b and b are shown as cylindrical and having equal diameters.
  • FIG. 9a shows aprojected view of these three elements in a plane parallel to the horizontal plane of assembly 121b, and FIG. 9b
  • a is a signed distance measured from the center of bar 105! on FIG. 9b, positive upwards.
  • a is negative.
  • a second dimension is used for purposes of simplifying the expression.
  • the devices of FIGS. I and 2 vary a to change A to the desired value.
  • A is seen to be a function of sin a only, once a geometrical configuration has been chosen.
  • a is easily written in terms of the amount armatures 115a and 115b are extended, and A can then be expressed as a function of armature position only.
  • the positions for a number of tracks over the width of strip l02e are selected, the amount of offset required for each can be easily determined, and the formulae solved for the armature position required for addressing each track.
  • the external controller (205 in FIG. 2) supplying strip shifting or voice-coil signals on lines 1190 and ll9b can be easily programmed to supply the desired one, of a discrete set of signals which. positions armatures 114a and 11411 to allow addressing the desired track.
  • FIG. 2 a complete, operational system is displayed.
  • the means employed in shifting stripsection 102e are exactly the same as in FIG. 1.
  • the apparatus of FIG. 1 does not store a sufficient amount of data to be competitive with alternative storage means. Since the two systems are similar, FIG. 2 will be described in terms of the differences between the apparatus it displays and that of FIG. I.
  • FIG. 2 The apparatus of FIG. 2 is almost identical to a prototype device now in operation, differing only in that guide bar assembly pivots 122a and l22b (see FIG. 1) are positioned midway between the ends of assemblies 121a and l2lb. This change was made for ease in displaying and explaining the operation of the invention by not obscuring the assemblies.
  • FIG. 8 displays the preferred arrangement.
  • Drum 101 of FIG. 2 has been changed inthat, as previously explained, a plurality of heads 111 are present, the pair of dotted lines indicating their position on drum 101. Addition of several heads to drum 101 permits more rapid accessing of a desired track because strip section 102 need not be moved as great a distance, on the average, in each accessing operation.
  • Strip 102 in the device of FIG. 2 is long enough to have many blocks of data on it, a block being the designation for all the data that may be accessed by heads 111 by only moving strip segment 102s laterally.
  • the excess length of the strip 102 is stored on spools or capstans 208a and 208!).
  • Driving reels 208a and 208! are reel drive motors 210a and 2l0b respectively (see FIG. 4).
  • Strip segment 102a, immediately adjacent strip roll 20lb on reel 208b, extends to, and partially encircles idler bar 202b. Idler bar 202b is necessary in this embodiment to preserve the parallel relationship between strip segments l02b and 102d.
  • Idler bar 202a is added adjacent strip roll 201a for the identical reason.
  • Strip edge sensors 212a and 2l2b are attached to frame 100 and placed adjacent the edges of strip segments 202i and 102a, respectively. Sensors 212a and 212b detect the position of the edge of the adjacent strip segments; and transmit signals encoding the lateral position of strip segments 102i and 102a via data lines 238a and 238b respectively, to controller 205.
  • drive motors 210a and 21% cooperate to keep proper tension on strip 102.
  • drive motors 210a and 21% By providing for opposing torques from drive motors 210a and 21% creating equal and opposing forces at the unrolled strip section adjacent rolls 201a and 201b, the proper tension on strip 102 is maintained.
  • a wide range of tension may be suitable for a given strip 102, with a strip comprising a 0.0015 in. MYLAR (registered DuPont trademark) plastic film base 22 in. wide, tension ranging from 50 to lbs. has been found satisfactory.
  • Controller 205 in addition to providing all the various control functions necessary in operating the apparatus, also receives commands and status information from an external data processor 225, for which this invention forms a piece of peripheral equipment.
  • the controller per se, does not constitute any part of this invention. Design ofa controller providing the proper control signals to the apparatus and correctly interpret the command status signals received by it, is a matter of design techniques well known in the art. Therefore, controller 205 will be discussed only in terms of the block diagram of FIG. 3, in conjunction with the overall discussion of the operation of this embodiment.
  • FIG. 2 has greater capacity than that of FIG. 1 not only because of the greatly enlarged area available for data storage, but also because of increased density at which data is stored.
  • One of the significant advantages of the invention lies in the fact that very accurate lateral positioning of strip segment 102e is possible if feedback techniques are used.
  • a strip position sensor is therefore provided.
  • the strip position sensor comprises voice coil 21% attached to frame with armature 2l8b projecting toward strip segment l02e and generally parallel to the axis of drum 101. Attached to the end of armature 218b adjacent strip 102e is sensing element 220b.
  • Sensing element 220b senses the position of strip segment 102a relative to it and transmits data encoding this position in the form of a sensing element position signal to controller 205 via data line 221b.
  • the position of armature 2l8b is sensed by sensing element position sensor 217b which is attached near voice coil 21% in such a manner that the distance armature 218b is extended can be sensed and the position encoded and transmitted via data line 227b to controller 205.
  • a similar means for detecting the position of the right-hand portion of strip segment 102e is shown in FIG. 4 as comprising voice coil 219a with armature 218a, strip position sensor 220a, sensing element position sensor 217a and data lines 221a, 236a and 227a.
  • FIG. 2 in terms of differences from FIG. 1, several more variations are necessary to realize the improved operation of which the embodiment of FIG. 2 is capable. Since a plurality of heads 111 are employed, it is unnecessary to shift strip segment 102e laterally a distance greater than the greatest distance between a pair of adjacent heads 111 to permit access to every track on strip segment 1022. Thus, the variation in angles A and B is also greatly reduced, as is the maximum movement of armatures 115a and ll5b. Not only is track addressing thereby speeded up by the use of multiple heads, but data rates may also be increased, since it is a simple matter to arrange for all or several of the heads 111 to simultaneously transcribe data.
  • each head is aligned on the surface of drum 101 as indicated by reference numeral 111 in FIG. 2.
  • Track density i.e., the distance between the centers of adjacent tracks, is 0.01 inch in a preferred design.
  • I30 tracks are accessed by a single transducing head 111.
  • the location of each track on strip segment l02e can be specified in terms of a fixed distance from the left edge of strip segment 102e.
  • Sensing elements 220a see FIG.
  • sensing element position sensors 217a and 2171 precisely measure the distance of the left edge of strip segment 102:: from a vertical datum plane when sensing elements 220a and 220b are at a preferred position with respect to an edge of strip segment l02e.
  • This vertical datum plane fixed with respect to heads 111, is perpendicular to the axis of drum 101- and passes through the sensing element position sensors 217a and 2I7b.
  • the known distance of a desired track from the left edge of strip segment l02e plus the measured distance of this edge from the datum plane i.e., armature length
  • the known distance of a desired track from the left edge of strip segment l02e plus the measured distance of this edge from the datum plane i.e., armature length
  • angles A and B are adjusted by signals from controller 205 to voice coils 114a and 1141; to cause strip segment l02e to move laterally and equalize these two measurements.
  • controller 205 adjusts the angle of the appropriate guide bar assembly by changing the position of the armature of voice coil 114a or 11411 only.
  • FIG. 3 discloses the elements of controller 205 and a preferred embodiment of the strip edge sensor assembly.
  • Block numbers of the strip are transmitted to control unit 302 from an external source, such as data processor 225 (FIG. 2), via line 230b.
  • Track and head numbers are transmitted to address decoder 301 via line 230a from the external source.
  • the track address is transmitted from address decoder 301 to sensor position control 302 via line 304.
  • armature 2l8b still carries sensing element 220b. But bracket 222b has been changed to enable it to carry a second sensing element 228b on the opposite side of strip 102.
  • the sensing element signals are transmitted on lines 2161: (for sensor 228b) and 22111 to strip control unit 302.
  • the distance separating the sensitive areas of sensing elements 220b and 228b is approximately equal to the width of strip 102 so as to allow the outputs of the sensing elements to simultaneously vary with relative motion between bracket 222b and strip segment 102a.
  • the balance position the output of elements 220b and 228b are equal. Normally, this will be when segment 102e is located symmetrically between them, covering an equal part of the sensing area of each.
  • Sensor 217b detects movement of scale 2l5b-and transmits sensing element position signals via line 227b to sensor position control 303.
  • Strip control unit 302 receives signals from block sensor 211 mounted adjacent sensor 220b (see also FIG.
  • Strip control unit 302 supplies control signals to voice coils 114a and l14b via lines 119 a and 119b, respectively, and to the left and right reel motors 2101) and 210a, via lines 232b and 232a respectively.
  • Sensor position control 303 supplies sensor shifting signals to voice coil 21% via line 236b.
  • Control of track selection is one of the functions of controller 205.
  • 16 heads present on drum 101 may be numbered left to right, 0 through 15.
  • Each head is used to accessthe already-mentioned group of I30 side-by-side tracks.
  • the tracks accessed by head 0 are the leftmost I30
  • those referenced by head 1 are the lying closest to those accessed by head 0, etc.
  • Each individual track in a contiguous group of I30 accessed by a single head 111 may be given an identifying number 0 through 129 from left to right as shown in FIG. 3.
  • each track may be uniquely identified on the basis of its head and track numbers.
  • Each track address received from data processor 225 on data line 230a contains this information.
  • Address decoder 301 computes the distance the left edge of strip segment 3102b must be from the vertical datum plane to permit the specified head 111 to reference the desired track. This is done by forming the product of the track number and 0.01 inch, and summing this product with the known distance of track of head 0 from the left edge of strip segment 102a. As previously explained, the sum of this distance plus the distance of the left edge of strip segment l02e from the datum plane as measured by sensors 21712 and 217a must equal the fixed distance that head 0 is from the datum plane to permit addressing the desired track.
  • the sensing elements are photocells. Accordingly, it is necessary to have light sources supplying light to them.
  • light source 229b is located on bracket 222b so that its output is directed across the right-hand channel in bracket 22212 and onto the sensing area of photocell 228b.
  • a similar arrangement is present for photocell 220k. As bracket 222b and strip segment 102e shift relative to each other, none, part, or all of the light directed toward a photocell will strike the sensitive area, thereby varying the sensing element signal being sent from the photocell to strip control unit 302. Photocells are but one kind of sensing element which will provide the accuracy needed.
  • a pair of air jets located in the positions occupied by the photocells are an acceptable alternative.
  • Mechanical fingers or feelers driving a potentiometer are another possibility.
  • Voice coil 21%, armature 218b, edge sensors 228b and 220b, and sensor control 303 comprise a servo system.
  • Strip control unit 302 endeavors to maintain strip 102 in the balance position with respect to photocells 228b and 220b at all times.
  • sensor control unit 303 keeps a sensor shifting signal on line 236b to voice coil 2l9b keeping the position of armature 218k fixed. If strip 102 shifts to the right relative to photocells 220!) and 228b (perhaps caused by a slight error in the strip shifting signal received by voice coil ll4b), photocell 22% will become more uncovered and photocell 228b will become less covered.
  • strip control unit 302 detects this difference and varies the strip shifting signal to voice coil 21% to shift strip segment 102e further to the left, tending to cause sensor 220b to be more covered, and sensor 228b to be less covered. As strip segment 102s approaches the balance point, the difference between the two signals from sensor 228b and 220b decreases, and when perfectly balanced, voice coil 114k ceases movement of armature 2l8b except for possible slight hunting inherent in the servo loop.
  • sensors 220b and 228b can be considered to provide signals to control unit 302 exactly specifying the movement of strip segment 102e necessary for precise addressing of the desired track.
  • a similar assembly controls the position of the end of strip segment 102a adjacent idler bar 110a.
  • a second servo loop is energized.
  • the output of the address decoder on line 305 to sensor position control 303 specifies the position which armature 21% should assume to place strip segment 102e in position to permit addressing of the specified track when strip segment l02e is in its balance position with respect to bracket 222b. This signal is the set point.
  • sensor position control 303 changes the sensing element position signal to voice coil 21% to start driving bracket 22212 to the desired position. The movement of armature 2l8b destroys the balance position.
  • Strip control unit 302 detects the lack of balance between the output of sensing elements 220b and 228b (the feedback, or error, signal) and immediately reacts as explained above, to restore the balance position. Ideally, the response by strip control unit 302 and voice coils 114a and 1114b is so rapid, that strip 102 will follow along bracket 222k without getting more thana few hundredths of an inch away from the balance position.
  • armature 2l8b reaches the position which will place the end of strip segment 102a in proper position when strip segments 21% reaches the balance position, this'fact will be detected by sensor position control 303 from the sensing element position signal on line 227b. The sensor shifting signal is then changed to halt movement of armature 218 b.
  • a similar arrangement positions the end of strip segment 102e adjacent idler bar a.
  • Both the feedback and set point signals maybe digitized in which case a digital comparison is performed.
  • a preselected difference between them may be designed into the controls which must be exceeded before either strip or sensor position is corrected.
  • Mechanisms such as this have been employed for many years in, e.g., disc memories for track selection. Thus no great difficulty is presented to a skilled designer in adapting such controllers to the present device.
  • FIG. 10 therein is shown an alternate embodiment of the controller.
  • the apparatus of FIG. 3 causes strip 102 to follow the strip position sensors as it moves responsive to a change in the track specified. It is also possible to move strip segment 102e responsive to the track address signal, and follow the moving strip with sensors 220a and 220b, relying on the sensing element position signal to indicate when the specified track is in position for addressing. In this situation, it is necessary that strip segment 102a move slowly enough to permit voice coils 119a and 11% to keep up3[ with it. Accordingly, in H0. 10 is shown a strip control unit 302 receiving the track address signal online 304, and supplying strip shifting signals on lines 119a and 11% to voice coils 114a and 1114b.
  • sensing elements 22% and 228b will lose their balance position and change the sensing element signal on 22lb and 2l6b.
  • Sensor position control 303 reacts by transmitting a sensor shifting signal on line 236b to voice coil 21% to cause armature 21812 to move bracket 222b back into the balance position. This movement is detected by sensing element position sensor 217b and transmitted to strip control unit 302 on line 227b. This signal closes the loop. If the sensing element position signal on line 227b is an accurate measure of the actual position of strip segment 102e, then by merely comparing it to the track address signal, the movement of strip segment 102e can be stopped at the position allowing addressing of the specified track.
  • each block on strip 102 may be assigned a number, the numbers starting with l for the innermost block on spool 208b, and increasing consecutively toward the innermost block on spool 208a.
  • control unit 302 When a new block number is received by control unit 302, it must compare this number with the number of the block currently in addressable position. Accordingly, there is provided within controller 205 means for storing the current block number of the currently addressable block. By comparison of the relative magnitudes of the two values, the direction and the number of blocks to travel to reach the new block may be easily determined.
  • Control unit 302 issues signals to left and right reel motors 21% and 210a causing these reel motors to simultaneously pay out the correct length of strip from the correct reel and take up a similar length of strip on the opposite reel.
  • strip rolls 201a and 20lb be accurately rolled up, i.e., that the edges of successive.
  • both guide bar assembly angles A and B may be positioned so no offset at all exists in the position of strip segment l02e.
  • Strip edge sensor 212b continuously monitors the position of strip segment 102a and signals the occurrence of any detectable deviation from the preselected position to control unit 302 via line 238b. Control unit 302 reacts by causing voice coil 114!) to change angle B very slightly as needed to correct this deviation.
  • a marker must be present between each block of data on strip 102 for detection by interblock marking sensor 211. As each marker passes beneath sensor 211, a signal transmitted to control unit 302 permits the updating of the current block number register.
  • Sensor 211 may conveniently be a photocell and have an adjacent light source shining onto strip 102.
  • each interblock marking may be a small, silvered piece of tape attached adhesively to strip 102 so as to pass beneath sensor 211 as the strip is unwound from one reel and wound up on the other and reflect light from the source to the photocell.
  • the interblock markers may encode the actual block number of the adjacent block, thereby permitting direct detection of each block number.
  • FIG. 5 therein is shown an alternative strip-shifting means.
  • Guide bars 105b and 105a slide in slots 501k and 501a respectively.
  • the position of guide bar 105k is controlled by voice coil 114k and armature 1l5b supported by bracket 503b.
  • the force from armature 1l5b to move bar 10511 in slots 501b is exerted through bracket 502b.
  • bracket 502b Only the slots 501a are shown for bar 105a, but the construction for the elements not shown is identical.
  • the apparatus of FIG. 5 depends for the shifting of strip 102 on a fixed slight angle which each pair of guide bars make with the vertical plane. Arbitrarily, these angles have both been chosen as obtuse,
  • the distance between guide bars 10512 and 106b is near its maximum.
  • offset can be controlled by varying dimension a. Since an gles A and B are both obtuse, the strip is offset to the left near its maximum amount when guide bars 105a and 1051; are in the positions displayed. As dimension a is decreased for each pair of guide bars, offset decreases and strip segment 102e shifts to the right. Thus, by simply positioning guide bars 105a and l05b properly, strip segment 102e may be shifted axially on drum 101. Depending on the distance which segment 102e must be shifted, the obtuseness of angles A and B, and the change possible in dimension a may have a wide range of variation.
  • the position of the movable guide bar adjacent the takeup spool can be slid back and forth in its slots to precisely steer strip 102 onto the takeup spool.
  • the remainder of the operation is identical in concept to that of the device of FIG. 2.
  • FIGS. 7a and 7b detail the means for creating the air bearing interface between strip 102 and those surfaces over which it slides axially.
  • Guide bar l05b has been arbitrarily selected for purposes of illustration.
  • Line 701 forms the center lines of orifices 703 placed on the surface of guide cylinder 1051:.
  • Line 702 is the tangent line which strip segment 102d forms with cylinder l05b.
  • the arc subtended by lines 701 and 702 should be 5. It should of course be understood that two sets of orifices 703 are necessary, adjacent each tangent line formed by strip 102 with the bar.
  • orifices 703 are each 0.03 inches in diameter and are spaced at 0.8 inch intervals.
  • An external compressed air source provides a pressure of 8 psig at each orifice.
  • FIG. 8 displays the previously mentioned alternative embodiment for pivoting a pair of guide bars.
  • a pair of voice coils 806 and 808 are provided at opposite ends of guide bar assembly l2lb.
  • Pivot 805 is located central to the ends of the guide bars.
  • Voice coils 806 and 808 are arranged to assist each other in pivoting guide bar assembly 121a. That is, when the armature of one extends to pivot guide bar assembly 121b, the armature of the other is being simultaneously retracted by the signals from controller 205.
  • the guide bars may be moved to a new angle more rapidly in this configuration, because the rotational inertia of the guide bar assembly about the pivot is decreased with a central pivot. Vibration of the guide bar assembly is decreased as well, because the guide bar assemblies are supported at three rather than two places.
  • apparatus for accessing with a data transducer having a transcribing surface, a longitudinal recording track on an elongate flexible recording strip and specified by a track address signal comprising:
  • first and second strip holders attached to the frame at spaced apart locations and holding the strip at, respectively, first and second areas on the strip between which is located a first strip section having at least two recording tracks on its surface;
  • transducer holding means for maintaining the transcribing surface of the data transducer within a predetermined data transcribing distance of the first strip section and moving the transducer relative to the first strip section in a path having a shape substantially the same as the recording tracks;
  • control means receiving the track address signal, for determining the strip position placing the track specified by the track address signal within the predetermined data transcribing distance of the transcribing surface of the transducer, and supplying a strip shifting signal to the strip shifting means spcifying this position.
  • strip shifting means comprises:
  • first through fourth guide bars at least a part of the exterior of each being a convexly curved cylindrical surface
  • a first adjustable guide bar support attached to the frame in a position holding the first and second guide bars againstopposite strip surfaces between the transducer and the first holder with the convex surface of these two bars at least partially encircled by the strip, and forming the strip into second, third, and fourth flat sections tangent to the convex surface of the first, second, and both guide bars respectively, with the tangent lines of the fourth sec tion with the first and second convex guide bar surfaces being parallel;
  • a second adjustable guide bar support attached to the frame in a position holding the third and fourth guide bars against opposite strip surfaces between the transducer and the second holder with the convex surface of each bar at least partially encircled by the strip, and forming the strip, into fifth, sixth and seventh flat sections tangent to the convex surfaces of the third, fourth and both guide bars respectively with the tangent lines of the seventh section with the third and fourth convex guide bar surfaces being parallel;
  • first and second means moving the first and second guide bar supports respectively and changing the positions of the guide bars relative to the transducer holding means for shifting the strip transversely with respect to the recording tracks thereon to the position specified by the strip position signal.
  • first and second guide bar supports include respectively first and second pivots attached to the frame and positioning the bars to make the second and fifth strip sections parallel respectively to the fourth and seventh strip sections and perpendicular respectively to the axes of rotation of the first and second pivots; and wherein the support moving means includes means for pivoting the first and second guide bar supports about their respective pivots.
  • guide bar support pivoting means further comprises means for pivoting the first and second guide bar supports substantially equal amounts.
  • each support pivoting means further comprises a voice coil connected between the support and the frame.
  • first and second guide bar supports further comprise respectively first and second pivots attaching their respective supports to the frame at points between the ends of the bars held by each support, and wherein each support pivoting means comprises a pair of elements each having a pair of spaced apart control points whose distance apart varies responsive to the strip position signal, a control point of one element attached to its associated support with the other control point of each element attached to the frame.
  • each element comprises a voice coil having one control point on the armature and the other on the field.
  • each pair of elements comprising a support pivoting means comprises positioning devices whose distance between control points varies equally responsive to identical strip position signals.
  • each positioning device comprises a voice coil attached so as to substantially form a right angle with a line connecting the points of attachment of the voice coils to the support when the strip is approximately midway between its extreme positions.
  • first and second guide support moving means each include respectively means for causing the distance between the first and second and the third and fourth bars to change maintaining meanwhile the specified geometric relationships, and further comprising means for attaching the guide bar supports to the frame in a position placing the lines of tangency formed by the fourth, and seventh strip sections at predetermined angles to a plane perpendicular to the drum axis, and placing the second and fifth strip sections parallel respectively to the third and sixth strip sections.
  • bar distance changing means further comprises means for maintaining the distances between the first and third, and second and fourth, guide bar substantially equal.
  • support attaching means further comprises means for attaching the guide bar supports so as to place the bars at substantially equal angles to the data track.
  • transducer holding means comprises a circular drum rotatably mounted on the frame and partially encircled by the first strip section, and having the transcribing surface of the data transducer embedded in and facing outwardly from its curved surface.
  • the apparatus of claim 14 further comprising a. first and second idler bars, at least a part of the exterior of each being a convexly curved cylindrical surface;
  • a first idler bar support attaching the first idler bar to the frame immediately adjacent the drum with the convex surface of the first idler bar at least partially encircled by the strip and the lines of tangency formed by the strip section between the first idler bar and the drum substantially parallel;
  • a second idler bar support attaching the second idler bar to the frame immediately adjacent the drum on the side opposite that of the first idler bar with the convex surface of the second idler bar at least partially encircled by the strip and the lines of tangency formed by the strip section between the first idler bar and the drum substantially parallel.
  • the apparatus of claim 14 including means for maintaining an air bearing interface between the strip and at least one surface with respect to which it slides.
  • the air bearing means comprises a plurality of areas on the surface upon which the strip slides, each containing at least one aperture, and means for forcing air through the apertures.
  • the strip holders include means for applying tension within a predetermined range between them to the first strip segment.
  • strip holders each further comprise means for maintaining equal tension across the width of the strip and total tension within a predetermined range in the strip.
  • equal tensioning means further comprises first and second clamps, each non-slippingly gripping one end of the strip across substantially its entire width and attached respectively to the first and second strip holders.
  • first and second strip holders comprise, respectively, first and second storage spools rotatably attached to the frame; and means receiving the track address signal, for rotating each spool to unwind a length of the strip from one spool and concurrently take up a similar length on the other spool, responsive to the track address signal.
  • the apparatus of claim 22 further comprising third and fourth idler bars, at least a part of the surface of each having a convexly cylindrical shape and both attached to the frame, the cylindrical surface of the third always at least partially encircled by the strip portion immediately adjacent the second takeup spool, the tangent lines of each strip section between each idler bar and its associated storage spool being parallel and coplanar.
  • the apparatus of claim 22 further comprising third and fourth idler bars, each having a partially convex cylindrical surface and each attached to the frame to allow the strip segments immediately adjacent the first and second storage spools to at least partially encircle the convex surfaces of the first and second idler bars respectively.
  • the strip has a plurality of block markers at predetermined intervals, and wherein the track address signal includes a block address signal; wherein the spool rotating means further comprises means receiving a block location signal for taking up on one spool and unwinding on the other spool, a sufficient length of strip to position an addressed block to partially encircle the drum;
  • control means further comprises means sensing the current position of the strip for supplying a block location signal to the spool rotating means.
  • control means comprises:
  • a strip position sensor including a strip sensing element, attached to the frame, and supplying a strip position signal specifying the strip position
  • a controller receiving the strip position signal and the track address signal, comparing them to determine the strip shifting signal to move the strip to the position for addressing the specified track, and supplying this strip shifting signal to the strip shifting means.
  • the strip position sensor comprises a strip edge sensor issuing a strip position signal specifying the position of the edge of the first strip segment.
  • the strip position sensor includes a carrier movably attaching the sensing element to the frame and shifting the element in a path substantially parallel to the axis of the drum responsive to a sensor shifting signal, and supplying a signal specifying the position of the sensing element.
  • controller further comprises means for shifting the sensing element responsive to the track address signal to a position causing the strip position signal to have a predetermined value when the specified track is being addressed, and for supplying a strip shifting signal to the strip shifting means causing the strip to shift until the predetermined strip position signal value is reached.
  • the strip position sensor comprises a pair of strip edge sensors each furnishing a strip position signal varying as the strip moves between a pair of predetermined positions relative to the edge sensors.
  • each edge sensor comprises a photocell.
  • controller further comprises:
  • a. means supplying a strip shifting signal to the strip shifting means responsive to the track address signal, for causing the strip to move laterally toward the position permitting addressing of the specified track by the head and to stop the lateral strip movement responsive to an accessing value of the sensor c.
  • the strip position sensor includes means for supplying the accessing value of the sensor posi tion signal to the controller when the strip approaches the specified position.
  • the transducer holding means comprises a circular drum rotatably mounted on the frame and positioned to be partially encircled by the first strip section, and having the transcribing surface of the data transducer embedded in and facing outwardly from its curved surface
  • the strip shifting means comprises:
  • first through fourth guide bars at least a part of the exterior of each being a convexly curved cylindrical surface
  • a first guide bar support movably attached to the frame and positioned to hold the first and second guide bars against opposite strip surfaces between the transducer and the first holder with the convex surface of each bar at least partially encircled by the strip, and forming the strip into second, third, and fourth flat sections tangent to the convex surfaces of the first, second, and both guide bars, respectively, with the tangent lines of the fourth section with the first and second guide bar convex surfaces being parallel;
  • a second guide bar support movably attached to the frame and positioned to hold the third and fourth guide bars against opposite strip surfaces between the transducer and the second holder with the convex surface of each bar at least partially encircled by the strip, and forming the strip into fifth, sixth and seventh flat sections tangent to the convex surfaces of the third, fourth and both guide bars, respectively with the tangent lines of the seventh section with the third and fourth guide bar convex surfaces being parallel;
  • first and second means moving the first and second guide bar supports respectively and changing the positions of the guide bars relative to the transducer holding means for shifting the strip transversely with respect to the recording tracks thereon to the position specified by the strip position signal.
  • first and second guide bar supports include respectively-first and second support pivots attached to the frame and positioning the bars to make the second and fifth strip section parallel respectively to the third and sixth strip sections and perpendicular respectively to the axes of rotation of the first and second pivots; and wherein the support moving means includes means for pivoting the first and second guide bar supports to cause the first strip section to shift responsive to the strip position signal to a position relative to the transducer permitting the addressed track to be traversed by the transducer as it moves relative to the first strip section.
  • the support pivoting means further comprises means for maintaining the axes of the bars supported by the first support at an angle measured clockwise from the axes to a plane perpendicular to the drum axes, equal to the angle measured counterclockwise from the axes of the bars supported by the second support, to the plane.
  • first and second strip holders comprise respectively, first and second storage spools rotatably attached to the frame and means receiving the track address signal, for rotating each spool to unwind a predetermined length of the strip from one spool and concurrently take up a similar length on the other spool, responsive to the track address signal; and to maintain a predetermined tension in the strip section between the taken-up lengths on the spools during transducing operations.
  • the apparatus of claim 37 including a strip position sensor mounted on the frame and supplying a signal specifying the location of the first strip segment relative to the data transducer path to the strip position control means; and wherein the strip position control means further comprises a comparator receiving the track address signal and determining therefrom the transverse position of the strip permitting the data transducer to access the track, comparing the strip location to the strip location permitting track access, and issuing the strip position signal to the strip shifting means.
  • strip position sensor comprises a strip edge sensor issuing a strip edge position signal specifying the position of the edge of the first section relative to the data transducer path.
  • At least one guide bar includes means for creating an air bearing contact between the strip portion encircling it and the guide bar.
  • the air bearing creating means comprises a plurality of areas on the strip-encircled surface of the guide bar having orifices therein, and means for supplying compressed air to these orifices.
  • strip shifting means comprise:
  • first and second guide bars and third and fourth guide bars comprising first and second guide bar pairs respectively, at least a portion of each guide bar being a convexly curved cylindrical surface;
  • c. means receiving the strip shifting signal for varying the positions of the guide bars to change the offset of the strip between the pairs of guide bars, responsive to the strip shifting signal.
  • the guide bar position varying means comprising means for varying the angle of the guide bars to the longitudinal axis of the strip.
  • the guide bar positioning means comprises means for varying the distance between the first and second, and between the third and fourth, guide bars.
  • the strip shifting means comprises means for bendingly changing the plane of the strip a plurality of times adjacent to the first strip section thereby transversely shifting the position of the first strip segment an amount specified by the strip-shifting signal, and further bendingly changing the plane of the strip a plurality of times adjacent the first strip segment and on the side of the first section opposing that of the first plane changings, to restore the strip to its original position.
  • Apparatus for shifting a segment of an elongate flexible strip transversely with respect to its longitudinal axis comprising:
  • first and second guide bars and third and fourth guide bars comprising first and second guide bar pairs respectively, at least a portion of each guide bar being a convexly curved cylindrical surface;
  • first and second strip holders attached to the frame at spaced apart locations and adopted to grip the strip at spaced apart areas on the strip;
  • each guide bar mount further comprises means for varying the angle of the guide bars supported thereby, to the longitudinal axis of the strip.
  • each guide bar support comprises means for varying the distance between the guide bars supported thereby.
  • each guide bar support comprises means for changing the position of the guide bar pairs relative to the frame.

Landscapes

  • Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)
  • Registering, Tensioning, Guiding Webs, And Rollers Therefor (AREA)
  • Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
US00260602A 1972-06-07 1972-06-07 Lateral strip control apparatus Expired - Lifetime US3773983A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US26060272A 1972-06-07 1972-06-07

Publications (1)

Publication Number Publication Date
US3773983A true US3773983A (en) 1973-11-20

Family

ID=22989832

Family Applications (1)

Application Number Title Priority Date Filing Date
US00260602A Expired - Lifetime US3773983A (en) 1972-06-07 1972-06-07 Lateral strip control apparatus

Country Status (8)

Country Link
US (1) US3773983A (hu)
JP (1) JPS4957823A (hu)
AU (1) AU475281B2 (hu)
CA (1) CA1003564A (hu)
DE (1) DE2327390A1 (hu)
FR (1) FR2188232A1 (hu)
GB (1) GB1431949A (hu)
NL (1) NL7304826A (hu)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881414A (en) * 1973-08-20 1975-05-06 American Bank Note Co Apparatus for controlling the lateral position of an elongated web
US4740849A (en) * 1985-07-17 1988-04-26 Sony Corporation Guide arrangements for maintaining magnetic tape in proper position relative to a head

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2716026A (en) * 1951-10-25 1955-08-23 Union Wadding Company Web guiding device
US2797091A (en) * 1955-08-05 1957-06-25 Irwin L Fife Web shifting apparatus
US2919314A (en) * 1956-10-16 1959-12-29 Teletrak Corp Means for recording and/or reproducing recorded high frequency signals
US3024955A (en) * 1958-09-15 1962-03-13 Irwin L Fife System for centering a moving web
US3104789A (en) * 1963-09-24 figures
US3243089A (en) * 1963-01-18 1966-03-29 Reynolds Metals Co Sidewise alignment of a longitudinally moving strip and the like
US3570735A (en) * 1968-11-18 1971-03-16 Gpe Controls Inc Method and apparatus of guiding moving webs

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3104789A (en) * 1963-09-24 figures
US2716026A (en) * 1951-10-25 1955-08-23 Union Wadding Company Web guiding device
US2797091A (en) * 1955-08-05 1957-06-25 Irwin L Fife Web shifting apparatus
US2919314A (en) * 1956-10-16 1959-12-29 Teletrak Corp Means for recording and/or reproducing recorded high frequency signals
US3024955A (en) * 1958-09-15 1962-03-13 Irwin L Fife System for centering a moving web
US3243089A (en) * 1963-01-18 1966-03-29 Reynolds Metals Co Sidewise alignment of a longitudinally moving strip and the like
US3570735A (en) * 1968-11-18 1971-03-16 Gpe Controls Inc Method and apparatus of guiding moving webs

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3881414A (en) * 1973-08-20 1975-05-06 American Bank Note Co Apparatus for controlling the lateral position of an elongated web
US4740849A (en) * 1985-07-17 1988-04-26 Sony Corporation Guide arrangements for maintaining magnetic tape in proper position relative to a head

Also Published As

Publication number Publication date
NL7304826A (hu) 1973-12-11
AU475281B2 (en) 1976-08-19
CA1003564A (en) 1977-01-11
JPS4957823A (hu) 1974-06-05
AU5658273A (en) 1974-12-12
GB1431949A (en) 1976-04-14
DE2327390A1 (de) 1974-01-03
FR2188232A1 (hu) 1974-01-18

Similar Documents

Publication Publication Date Title
US3861619A (en) Magnetic tape position sensing
US4970612A (en) Magnetic tape apparatus comprising a control unit for controlling tape buffers, the tape tension and the tape-transport
US4863114A (en) Magnetic tape cartridge identification
US4913328A (en) Active tape tracking system with crown guide rollers for magnetic recorder/players
US3845500A (en) Head to track alignment in a rotating head magnetic tape unit
JPS5855574B2 (ja) テ−プロクオンサイセイソウチ
US4389600A (en) Tape media interlayer tension check
US5566039A (en) Read/write head positioning device
US3720930A (en) Thermal expansion compensator
US3773983A (en) Lateral strip control apparatus
US6633449B1 (en) High bandwidth tape positioning system and servo controlled rollers for active tape positioning
US4097005A (en) Web transport system
US6450438B1 (en) Apparatus and methods for forming a tape pack
US4652946A (en) Fast deploying tape transport
US3347437A (en) Tape guidance system
US4764826A (en) Tape cassette and cooperating apparatus
US3731890A (en) Digital magnetic tape transports
US6622113B2 (en) Method and apparatus for detecting and computing tape reel radius using low-resolution angular position sensors
JPH0896456A (ja) 情報記録再生装置
US7474498B2 (en) Tape recording system
KR900016986A (ko) 비디오 테이프 기록 및 재생장치
EP1691364A2 (en) Passive air bearing tape guide
JPS5870466A (ja) 磁気テ−プカセツト
US3439850A (en) Tape handling method and apparatus
JPH02201759A (ja) テーププレーヤのテープテンション制御装置