Abstract:
An expandable tape cartridge has a housing with a top and a bottom that are movable relative to each other between a minimum spacing and a maximum spacing. A tape reel with magnetic recording tape wound thereon is rotatably mounted in the housing for rotation around an axis proceeding substantially perpendicularly between the top and the bottom of the housing. The tape reel has insufficient clearance for free rotation within the housing when the spacing between the top and the bottom is at the minimum, and is freely rotatable when the spacing is at the maximum. This allows the width of the recording tape measured in a direction parallel to the rotational axis, to be increased, thereby increasing the storage area available on the recording tape without increasing the linear length of the recording tape.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention is directed to a cartridge of the type suitable for containing one or more wound reels of magnetic recording tape.  
           [0003]    2. Description of the Prior Art  
           [0004]    Due to the standardized design of tape drives, tape cartridges which are respectively used with the various types of tape drives have standardized form factors, which means that the cartridges have standardized exterior dimensions so as to be able to fit within the drive for which it is intended. As an example, a commonly used single reel cartridge has exterior dimensions of approximately 4″×4″×1″ and contains a tape pack having a tape of ½″.  
           [0005]    Since the exterior dimensions of the cartridge are fixed, efforts are continually being made to increase the interior volume that is available for containing the magnetic recording tape, since an ability to contain more magnetic tape within the cartridge means that more data can be stored.  
           [0006]    Some of these efforts have been directed to allowing a longer length of magnetic tape to be wound on one or more reels within the cartridge. Although increasing the linear length of the tape which can be contained in a cartridge having a given form factor will enlarge the total amount of surface area of the tape that is available for recording data, and thus will allow more data to be recorded on the tape, increasing the length of the tape also increases the access time to the data since the read/write head must be move linearly along the tape length in order to access the recorded data. If the tape has a longer length, this unavoidably results in a longer access time since a longer length of tape must be wound or unwound in order to bring the desired data adjacent to the read/write head.  
           [0007]    Expandable housings for tape cartridges have recently been developed to address the related problem of providing enough room within the interior of a tape cartridge to allow all, or substantially all, of the magnetic recording tape in a dual reel configuration to be wound on only one of the reels. When all of the tape is wound on only one of the reels, the resulting tape pack has an extremely large diameter. Co-pending U.S. application Ser. No. 10/052,839, filed Nov. 7, 2001 (“Wide Tape Holding Frame,” Rudi et al.) and co-pending U.S. application Ser. No. 09/859,328, filed May 16, 2001 (“Tape Cartridge With Expandable Cover,” Rudi et al.) have been developed to allow all or substantially all of a tape pack of wide tape to be contained on a single reel in a dual reel arrangement.  
         SUMMARY OF THE INVENTION  
         [0008]    It is an object of the present invention to provide a cartridge for magnetic recording tape having a standard form factor which allows an increased amount (surface area) of recording tape to be contained in the cartridge, thereby increasing the data storage capacity of the tape contained within the cartridge without deviating from the standardized form factor.  
           [0009]    It is a further object of the present invention to provide such a tape cartridge which allows more magnetic recording tape to be contained therein without increasing the linear length of the recording tape.  
           [0010]    It is further object of the present invention to provide such a tape cartridge wherein the ability to contain more tape within the cartridge does not result in a decrease in the structural strength or integrity of the overall tape cartridge.  
           [0011]    The above object is achieved in accordance with the principles of the present invention in an expandable tape cartridge having a housing with a relatively movable top and bottom having a spacing therebetween, wherein the spacing can be varied between a minimum spacing and a maximum spacing dependent on the relative movement between the top and bottom of the housing. A tape reel with magnetic recording tape wound thereon is rotatably mounted in the housing, so as to rotate around an axis that proceeds substantially perpendicularly between the top and bottom of the housing. The tape reel has a height parallel to the aforementioned axis. When the spacing between the top and bottom of the housing is at the minimum, the tape reel has insufficient clearance to freely rotate within the housing, but when the cartridge is expanded to the maximum spacing, the reel is able to freely rotate.  
           [0012]    As used herein, “freely rotate” means rotation in the manner necessary to wind or unwind the tape in a tape drive.  
           [0013]    The invention is in part based on the recognition that it is only necessary that the cartridge housing have interior dimensions permitting free rotation of the tape or reels therein when the cartridge is actually inserted in a tape drive. When the cartridge is removed from the tape drive, it is of no consequence if the interior dimensions are so small that free rotation is impeded by insufficient clearance between the tape reel and one or more of the interior walls of the cartridge.  
           [0014]    The top and bottom of the cartridge, therefore, are relatively movable (i.e., at a minimum, one moves relative to the other). By suitable loading, such as spring loading, the top and bottom are caused to be compressed when the cartridge is not in a tape drive, so that the aforementioned minimum spacing between the top and bottom results. When the cartridge is inserted into a tape drive, the loading mechanisms, such as the spring mechanisms are operated by suitable components within the drive so as to force the top and bottom apart, to the aforementioned maximum spacing, thereby allowing free rotation of the tape reel within the housing.  
           [0015]    This cartridge structure allows the width of the magnetic recording tape to be increased, the width being measured parallel to the rotational axis of the reel, and this contributing to the overall height of the reel. The total height is determined by the width of the tape and the thickness of the top and bottom flanges of the reel. The width of the tape can be additionally increased by providing a recess in one or both of the top and bottom of the cartridge housing, so that when the top and bottom are at the minimum spacing, one or both of the flanges are received into this recess. The height of the reel therefore is increased, and thus the spacing between the flanges is increased, thereby allowing for wider tape to be used. This recess causes a portion of the top or the bottom of the housing to become relatively thin in thickness and thus, by itself, this thinned region of the top or the bottom would not exhibit particularly high strength, and may be subject to damage when exposed to a force acting on the top or the bottom of the housing from the exterior of the housing. Protection against such forces, however, is necessary only when the cartridge is not located within the drive, i.e., when it is being handled or stored outside of the drive. When the inventive cartridge is outside of the drive, as noted above, the top and bottom exhibit the minimum spacing from each other, and therefore the thinned region of the top or the bottom is virtually directly adjacent one of the flanges of the tape reel. This flange of the tape reel, fitting into the recess, provides sufficient mechanical support and strength so that the overall structural integrity, in terms of its ability to protect the tape from exterior forces, is not significantly compromised.  
           [0016]    In the context of the above example of a single reel cartridge having a form factor of approximately 4″×4″×1″, the width of the magnetic recording tape can be increased from ½″ to ¾″. This means that the total tape surface area is increased by 50%, thereby also increasing the storage capacity by 50%, but without any necessity of adding to the linear length of the tape. Other common form factors are 102.00 mm×105.40 mm×21.50 mm, 105.79 mm×105.41 mm×25.40 mm and 125.00 mm×109.00 mm×24.50 mm. The width of the magnetic recording tape can be increased by a comparable amount in cartridges having these form factors as well. Measured in millimeters, this means the tape will have a width of approximately 19 mm in cartridges having these form factors. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1A is a perspective view of an expandable tape cartridge in accordance with the invention, in the embodiment of a single reel cartridge.  
         [0018]    [0018]FIG. 1B is a bottom view of the cartridge shown in FIG. 1A.  
         [0019]    [0019]FIG. 1C is a sectional view taken along line B-B of FIG. 1B.  
         [0020]    [0020]FIG. 1D is a side view of the cartridge in the expanded state shown in FIGS. 1A and 1B.  
         [0021]    [0021]FIG. 2A is a sectional view of the inventive cartridge, taken along line D-D of FIG. 2D.  
         [0022]    [0022]FIG. 2B is a plan view of the inventive expandable cartridge.  
         [0023]    [0023]FIG. 2C is a sectional view taken along line C-C of FIG. 2B showing the inventive cartridge in a non-expanded state.  
         [0024]    [0024]FIG. 2D is a side view of the inventive cartridge in the non-expanded state.  
         [0025]    [0025]FIG. 3 is an exploded view of the inventive expandable cartridge.  
         [0026]    [0026]FIG. 4A is a side view of a lock spring assembly used in the inventive expandable cartridge.  
         [0027]    [0027]FIG. 4B is a sectional view taken along line A-A of FIG. 4A.  
         [0028]    [0028]FIG. 4C is a perspective view of the lock spring assembly of FIG. 4A.  
         [0029]    [0029]FIG. 4D is a schematic representation of the lock spring assembly shown in FIG. 4A, indicating spacing which exist when the cartridge is in the expanded condition. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    The inventive expandable cartridge is explained below on the basis of a single reel embodiment, however, it will be apparent to those of ordinary skill in the art that the inventive principles can be employed in a dual reel cartridge as well.  
         [0031]    [0031]FIGS. 1A through 1D illustrate the inventive cartridge in the expanded state. The cartridge has a top cover  1  and a bottom cover  2 , which also has sidewalls integrated therewith. Magnetic tape is wound on a tape reel contained within the cartridge (neither the tape nor the reel being visible in FIGS. 1A through 1D). The free end of the magnetic tape has a leader block  3  allowing the tape to be pulled out of the cartridge housing in a known manner. The exterior of the cartridge has a notch  5  for loading the cartridge into a drive and a notch  6  for robotic handling of the cartridge. These notches are located at standardized positions so that a standardized load/unload mechanism (except for differences noted herein) can be used in the drive and standard robotic equipment can be used for handling the cartridge.  
         [0032]    The cartridge has four access holes  7  which allow access to four lift posts  19 . The hub of the tape reel has a toothed rim  8  which is accessible through an opening in the bottom cover  2 , as can be seen in FIG. 1B. Also visible in FIG. 1B is a protrusion of the hub lock part  16  (shown in more detail in FIGS. 2A and 2C).  
         [0033]    In the sectional view shown in FIG. 1C, the overall tape pack  14  is shown wound between two flanges  15  of the reel.  
         [0034]    The cartridge also includes a write inhibit switch  17  which is actuated in a known manner to preclude inadvertent overwriting of data on previously-recorded data on the tape.  
         [0035]    The top cover  1  has four mounting holes  18  for mounting lock spring assemblies, which are described in more detail below. The tape reel  33  has a window  21  for the protrusion  10  of the hub lock part  16 , the bottom cover  2  has a window  22  for the toothed rim  8 . The bottom cover  2  has four mounting holes  23  for the aforementioned lock spring assemblies. The write inhibit switch  17  is accessible via a window  24  in one of the sidewalls of the bottom cover  2 .  
         [0036]    The gripping notch  25  of the leader block  3  also can be shown in FIG. 1B.  
         [0037]    The distance designated Dl indicates the overlap between the top cover  1  and the bottom cover  2  in the expanded state. The distances D2 and D3 are the clearance dimensions between the reel flanges  15  and the top cover  1  and the bottom cover  2  in the read/write mode. The dimension D7 is the height of the cartridge in the expanded state.  
         [0038]    As can be seen in FIG. 1C, the top cover  1  has a recess  32  therein disposed in registration with the adjacent flange  15  of the tape reel. When the cartridge is in the non-expanded state, this flange  15  is received within the recess  32 , so that the thinned portion of the top cover  21  which creates the recess  32  is in extremely close proximity to, if not actually touching, the flange  15 . The flange  15  therefore, in the non-expanded state, serves to reinforce the thinned portion of the top cover  1 . The flange fitted into the recess  32  of the top cover  1  creates an overall effective thickness for the top cover  1  which is sufficient to provide the necessary protection against damage due to exterior forces acting on the cartridge during handling outside of the drive.  
         [0039]    As noted above, FIGS. 2A through 2D show the cartridge in the closed or non-expanded condition.  
         [0040]    In FIG. 2C it can be seen that the reel has a magnetic plate  9  for magnetic coupling to the toothed rim of a motor shaft of the drive motor of a drive in which the cartridge will be inserted. A toothed rim  11  is forced by a coil spring  12  into engagement with a mating toothed rim on the hub reel, thereby preventing rotation of the reel when the cartridge is out of the drive. The aforementioned hub lock part  16  can also be seen in FIG. 2C having a guide portion for the hub lock spring  12 . The cover lock sub-assembly can be seen in FIG. 2A.  
         [0041]    As can also be seen in FIG. 2C, the top cover  1  and the bottom cover  2  have overlapping sidewalls  30  and  29 , which slide relative to each other as the spacing between the top cover  1  and the bottom cover  2  varies. The hub core  31  is also shown in FIG. 2C as well as FIG. 2A.  
         [0042]    The distance D4 is the clearance distance between the inside of the top cover  1  and the outside of the hub reel flange  15 . The distance D5 is the distance between the inside of the bottom cover  2  and the outside of the flange  15 . The hub lock spring  12  forces the hub reel  15  into contact with a portion of the inside of the bottom cover close to the window  22  shown in FIG. 1B. The distance D5, which is approximately 0.1-0.2 mm, is necessary in order to avoid deformation of the flanges  15  when forces are applied against the cartridge housing. The distance D6 is the height dimension of the cartridge in the closed state. The aforementioned components are shown in an exploded view in FIG. 3.  
         [0043]    [0043]FIGS. 4A through 4D illustrate the operation of each of the lock spring assemblies  20 . Each lock spring assembly  20  has two interlocking elements  26  with a spring  27  disposed therebetween so that the opposite ends of the springs  27  are in mechanical engagement with the respective elements  26 . Each element  26  has a threaded hole  28  therein for attaching that element, by a screw, to the top cover  1  or the bottom cover  2 .  
         [0044]    When arranged as a sub-assembly outside of the cartridge, the elements  26  are forced by the spring  27  to a position where they are in contact with each other, i.e. the distance D8 indicated in FIG. 4B is 0. When the respective elements  26  are attached to the top cover  1  and the bottom cover  2  by screws proceeding through the screw holes  28 , the spring  27  will be compressed and the distance between the elements  26  will be D7. The top cover  1  and the bottom cover  2  then will be spring loaded toward each other by a force that is four times the force of the spring  27  (since there are four assembly  20 ) minus the force of the hub lock spring  12 . When the cartridge is fully expanded, each spring lock assembly  20  will appear as shown in FIG. 4D, with the distance D10 being a minimum (close to 0) and the clearance distance D9 being at a maximum.  
         [0045]    Other types of locking assemblies can be employed such as a tension spring, a leaf spring or torsion springs. Magnetic coupling or snap action also can be employed in the locking assembly.  
         [0046]    [0046]FIG. 4C shows the assembly  20  in a perspective view.  
         [0047]    The drive in which the inventive cartridge is intended to be used has two guide ribs for guiding the cartridge along the guide edges  4  shown in FIG. 1A as the cartridge is being loaded into the drive. These guide ribs in the drive are movable in a direction perpendicular to the flanges  15 . The drive also has four static pins which are located in registration with the lift posts  19  on the top cover  1 .  
         [0048]    When the cartridge is fully loaded into the drive, i.e., the center axis of the tape reel coincides with the center axis of the drive motor shaft, the guide ribs in the drive are moved downwardly, so that the lift pins  19  hit the static pins, and the top cover  1  stops its movement. The bottom cover  2  moves further downwardly until the toothed rim  8  on the tape reel engages a correspondingly toothed rim on the motor shaft. During this sequence, the protrusion  10  on the hub lock part  16  will hit the motor hub and the toothed rim  11  is lifted out of engagement. The tape reel is then lifted away from the bottom cover  2 . The vertical movement of the guide ribs stops when the distance D7 is reached. The four lock spring assemblies  20  are now in a position close to the “cartridge expanded” position shown in FIG. 4D. There is now sufficient clearance for rotation of the tape reel within the cartridge housing. The drive motor in the cartridge drive has a motor hub magnet which, in a known manner, exert magnetic forces to pull the steel plate  9  in contact to secure the drive engagement.  
         [0049]    The top cover  1  alternatively can be lifted without making use of the lift posts  19 . In this alternative embodiment, static ribs in the drive are located adjacent to the movable guide ribs. As the cartridge is located into the drive these pairs of ribs fit into the groove between the guiding edges  4  and the edge of the top cover  1 . When the cartridge is loaded and the vertical movement of the cartridge starts, the top cover  1  will hook onto the static ribs and the top cover  1  will remain in the same position as the bottom cover  2  begins its vertical movement. Otherwise the sequence is the same as described above.  
         [0050]    For unloading, the aforementioned sequence is reversed. When the cartridge is ready to be removed from the drive, the tape is tensioned and rotation of the tape reel is locked, and the cartridge is closed by the four lock spring assemblies  20 .  
         [0051]    Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.