Abstract:
A universal tape path subassembly that forms a data storage tape supply and path and fits within tape cartridge housings of varying form factors. The universal subassembly includes registration datum features and surfaces that can be made accessible externally to a tape cartridge (containing the tape path subassembly) for aligning the tape path subassembly relative to a drive unit adapted to receive the tape cartridge.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 09/440,459, filed Nov. 15, 1999, now U.S. Pat. No. 6,267,313 and claims priority from U.S. Provisional Patent Application Ser. No. 60/247,405, filed Nov. 10, 2000, both of which are incorporated herein by reference in their entirety for all purposes. 
     This application is related to co-pending U.S. patent application Ser. No. 09/577,637, filed May 24, 2000, which is incorporated herein by reference in its entirety for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to data storage devices and more particularly to tape storage devices using a wide tape cartridge. 
     Various types of tape cartridges are known in the art. One common type of tape cartridge includes a plastic box containing a feed reel for feeding a supply of magnetic tape spooled thereon, and a take-up reel for collecting the spooled tape from the feed reel after the tape has passed by an externally mounted write/read head assembly. Another type includes a plastic box containing a single feed reel having an end with a tape buckling mechanism for buckling onto a leader and then being drawn along a tape path within a tape drive. The latter type has typically employed one-half inch wide magnetic tape, and has been widely and successfully marketed under the Quantum DLT brand. 
     SUMMARY OF THE INVENTION 
     In one aspect of the invention, a universal tape path subassembly includes a chassis and a tape transport structure coupled to and supported by the chassis. Together, the chassis and tape transport structure form a data storage tape supply and path for use with tape cartridge housings of differing form factors. 
     Particular implementations of the invention may provide one or more of the following advantages. 
     The universal tape path subassembly can be used in different tape cartridges regardless of the external form factors of the tape cartridges. Moreover, the universal transport assembly can contain and use wide magnetic recording tape within a variety of tape cartridges having exterior form factors equivalent to, and compatible with, existing tape cartridge libraries and gripper-picker handling devices and systems. 
     In addition, precision registration datum points on the universal tape path subassembly and exposed by the housing can be used to ensure that the subassembly is in a correct position for accurately reading and writing on media. A tape drive transport can therefore be designed to accommodate these features instead of using the sides of the cartridge housing as is customary. These features and registration points can be standardized between different drive and cartridge manufacturers, enabling interchangeability with different styles and capacity cartridges. 
     Other features and advantages of the invention will be apparent from the following detailed description and from the claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric top view of a wide tape cartridge. 
     FIG. 2 is an isometric cut-away bottom view of a wide tape cartridge shown in FIG. 1 
     FIG. 3 is an exploded view of the wide tape cartridge of FIGS. 1-2 showing a universal tape path subassembly housed within. 
     FIG. 4 is a top view of a tape drive assembly for the wide tape cartridge of FIGS. 1-3. 
     FIG. 5 is an exploded isometric view of a wide tape cartridge subassembly within a DLT-style tape cartridge and form factor. 
     FIG. 6 is an exploded isometric view of a wide tape cartridge subassembly within an IBM 3480-style tape cartridge and form factor. 
     FIG. 7 is an isometric top view of a tape path subassembly in accordance with a second embodiment, similar to the FIG. 3 embodiment, with an extended height dimension to enable a greater supply of data storage tape to be stored and transported. 
     FIG. 8 is an isometric bottom view of the FIG. 7 subassembly. 
     FIG. 9 is an isometric top-front view of a media cartridge including the FIG. 7 subassembly. 
     FIG. 10 is an isometric bottom-rear view of the FIG. 9 media cartridge. 
     FIG. 11 is an exploded isometric view of the FIG. 9 media cartridge in a DLT-style tape cartridge. 
     FIG. 12A is a top plan view; 
     FIG. 12B is a right side elevational view; 
     FIG. 12C is a rear elevational view; and, 
     FIG. 12D is bottom plan view, of the FIG. 9 media cartridge. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1-2, a tape cartridge  10  includes a housing  11  having a lower housing member  12 , an upper housing member  14  and a head access opening  15  adapted to receive a head actuator (not shown). The access opening  15  may be closeable with an access door  16 . The tape cartridge  10  includes a number of cartridge identification and registration features, such as one or more or interposer notches  18  and a write-protect tab (not shown). The upper housing member  14  may be secured to the lower housing member  12 , for example, mechanically through snap-in connections with fasteners  20  which may be conventional screws, rivets and the like. In one practice, the upper housing  14  may include a number of holes  22  mating with respective screw bosses  24  or holes provided on the lower housing  12  and adapted to receive fasteners  20  for connecting the upper housing member  14  to the lower housing member  12 . Alternatively, or in addition, the upper and lower housing member may also be joined using an adhesive or by a welding process, or by other processes known in the art. 
     As seen in FIGS. 2 and 3, the upper and lower housing members  12 ,  14  enclose a tape path subassembly  30 . The tape path subassembly  30  includes a chassis  32  (having side members  32   a ,  32   b ) and a tape transport structure or mechanism  34  that is coupled to the chassis  32 . The tape transport structure  34  supports a wide tape  36  having a width of, for example, approximately 3½ inches. The tape transport structure  34  further includes a supply reel  38  and a take-up reel  40 . The tape  36  may be initially wound on the supply reel  38 , with the free end of the tape  36  to be wound onto the take-up reel  40  to transport the tape  36  in a transport direction indicated by the arrow  42 . Preferably, the chassis  32  is a precision chassis formed of a suitable rigid material such as plastic or metal. The tape reels  38 ,  40  are mounted on ball bearings (not shown), which provide journals between the reels  38 ,  40  and the chassis  32 , and have integrated flanges that hold the tape  36  in place during operation and prevent unwanted side-to-side motion of the tape  36 . 
     The reels  38 ,  40  are supported for rotation by the chassis  32  and have respective drive gears (or sockets)  44 ,  46  adapted to engage with respective motor driven couplings of a tape drive (not shown) for transporting the tape  36  in the longitudinal transport direction. Typically, one reel  38  or  40  may be driven by a drive motor, and the other reel  40 ,  38  braked, under the control of a drive motor controller. The drive gears are rigidly mounted to the reels, preferably along a common edge of the chassis  32  as shown in FIG.  3 . Also attached to each gear  44 ,  46  is a spring-loaded brake mechanism that locks each reel from rotating whenever a cartridge including the subassembly  30  is unloaded from/external to a drive apparatus. The top and bottom portion of the cartridge  10  may have a key, such as an exemplary transverse slot  48  located on the lower housing member  12  to ensure proper insertion and guiding of the cartridge relative to a head assembly of a tape drive within which the cartridge  10  is employed. Tape guides  50 ,  52  are positioned between the reels  38 ,  40  to define a reference plane of the tape  36  so that a head assembly can be inserted into the opening  15  for travel between the chassis side members  32   a  and  32   b  of the tape path subassembly. 
     In one embodiment, as shown in FIG. 3, the chassis  32  is a formed metal part that holds the two tape reels  38 ,  40  in precise position by virtue of aligned slots machined in the chassis side members  32   a ,  32   b . The slots hold the reels and thus the tape path of the tape transport structure  34  precisely parallel to each other, thereby ensuring smooth operation of the tape path. 
     Referring now to FIGS. 3 and 4, the cartridge  10  is shown inserted into a tape slot of a tape drive assembly  60 . The cartridge  10  is enclosed by a platform  62   a , top cover  62   b  and side covers  62   c  and  62   d . The platform  62   a  is attached to a cartridge lift mechanism  64  which can raise and lower the platform  62   a  and thereby also the cartridge  10  with respect to the chassis of the drive assembly  60  in a vertical direction indicated by the arrow  66 . The tape drive assembly  60  further includes drive couplings  68 ,  70  which are adapted to engage with the respective drive sockets  44 ,  46  to rotate the tape reels  38 ,  40 . Each of the drive couplings is secured together with a respective drive pulley  72 ,  74  on a common drive shaft (not shown) which is rotatably mounted in bearing supports  76 ,  78  secured to the drive assembly. Drive motors  80  having motor pulleys  82  are mounted on the assembly  60 . The motor pulleys may be coupled to the drive pulleys via conventional belts  84 . Other force-transmitting mechanisms, such as friction or toothed gears, may also be used. The cartridge lift mechanism  64  may be driven by a motor and a geared transmission or by other lifting mechanism known in the art. A head actuator (not shown) for actuating a head assembly attached thereto may also be mounted, for example, a surface  88  on the assembly  60 . The head actuator moves the head assembly bi-directionally in a direction indicated by arrow  89 . A head assembly enters the tape cartridge  10  through the opening  15 . A head actuator may be operated, for example, by a motor and/or a voice coil mechanism which provides coarse and/or fine positioning of the head assembly. The drive assembly  60  may also include a cartridge receiver mechanism  90  for sensing the presence and possibly also information about the type of a cartridge  10  in the drive assembly  60  as well as for opening the door  16  and locking the cartridge  10  in place. 
     The location of the tape path subassembly  30  and therefore also the tape  36  relative to the tape cartridge housing  11  may be subject to, among others, manufacturing tolerances. To provide a more precise registration between the tape  36  and a drive assembly chassis and thereby also a head assembly chassis, the tape path subassembly may be supported in the drive assembly  60  on datum surfaces  92 ,  94 ,  96  (of registration datum features or points  98 ) which are accessible from outside the tape cartridge housing. In the exemplary tape cartridge  10  of FIGS. 2 and 3, features are arranged essentially coplanar with a major surface of the lower housing member  12  and define a horizontal reference plane for aligning the tape cartridge  10  vertically relative to a drive chassis  60 . Additional datum surfaces engaging with reference surfaces located on the drive assembly chassis  60  may be used for registering the tape path subassembly  30  in the horizontal reference plane. 
     Referring to FIGS. 2-3, in the embodiment illustrated, there are three features  98 , which are formed on the chassis  32 , one on side member  32   a (feature  98   a ) and the other two on side member  32   b  (features  98   b  and  98   c ). Each of the features  98   a ,  98   b  and  98   c  includes a respective primary registration datum surface  92 . The features  98   b  and  98   c  on the side member  32   b  also include a respective secondary registration datum surface  94 . The feature  98   b  on the side member  32   b  also includes a tertiary registration datum surface  96 . Thus, the subassembly  10  is registered precisely along x, y and z axes of the drive apparatus  60 . These datum features align the complete assembly to corresponding features in the drive apparatus. This precision arrangement ensures that the subassembly  10  is in a correct position for accurately reading and writing on the wide tape  36 . The features  98   a ,  98   b  and  98   c  are exposed to a tape drive assembly in which the subassembly  30  resides via corresponding openings  99   a ,  99   b  and  99   c  in the lower housing member  12 . In the embodiment shown, the openings  99   b  and  99   c  are “T” shaped openings which enable contact with the features  98   b  and  98   c , respectively, on different surfaces of those features. 
     FIG. 5 illustrates the tape path subassembly  30  inserted into a digital linear tape (DLT) type plastic enclosure  100  that includes a base  102  and cover  104 . The enclosure  100  is similar in design to the enclosure  11  shown in FIGS. 1-3. FIG. 6 illustrates the tape path subassembly  10  inserted into an IBM 3480 style tape cartridge  110  that includes a base  112  and cover  114 . The DLT style enclosure  100  and the IBM 3480 style enclosure  110  are notably different in external form factor, with the IBM 3480 style cartridge  110  being longer and wider, and with the DLT style cartridge  100  being thicker. With the universal tape path subassembly  10  as thus described and assuming both enclosures  100  and  110  are designed to expose the registration features of the subassembly  10 , the enclosure form factors are irrelevant beyond the exposed datum surfaces ( 92 ,  94 ,  96 ) and features  98  (shown in FIGS.  2  and  3 ). A tape drive transport can therefore be designed to accommodate these features, eliminating the need to use the sides of the cartridge enclosure (for purposes of registration). These features and registration points can be standardized between different drive and cartridge manufacturers, enabling interchangeability with different styles and capacity cartridges. 
     FIG. 7 illustrates an alternative embodiment  200  of a wide tape path subassembly. The subassembly  200  includes a formed metal precision chassis  202 , flanged tape reels  204  and  206 , wide magnetic tape  208 , an access door  210 , a feed reel gear  212 , a take-up reel gear  214 , a feed reel brake  216  and a take-up reel brake  218 . As shown in the figure, the formed metal chassis  202  is most preferably an open truss-like structure that provides suitable strength and rigidity while using a minimum of metal, thereby reducing weight. As formed, the subassembly  200  has a form factor suitable for inclusion within a standard width and depth DLT tape cartridge housing, but requires an extended height dimension to enable a larger diameter supply of storage tape to be spooled on reels  204  and  206  and transported therebetween. 
     As with the subassembly  10 , the chassis  202  holds the two tape reels  204  and  206  in accurate position by means of slots machined in chassis endwall portions  220  and  222 . The slots hold the reels and thus the tape path precisely parallel to each other, ensuring smooth operation of the tape path. Also located with great precision to the reel slots are registration features and datum surfaces, as shown in FIG.  8 . In FIG. 8, primary registration points  224 , secondary registration points  226 , and at least one tertiary registration point  228  (like the surfaces or points  92 ,  94 ,  96  of features  98  shown in FIG. 3) provide datum surfaces and features for registering the subassembly  200  with the drive mechanism. 
     The tape reels  204  and  206  are most preferably mounted on ball bearings. The tape reels  204  and  206  have integrated flanges that hold the magnetic media  208  in place during tape travel operations and prevent undesirable side-to-side motion of the tape. Each drive gear  212 ,  214  is rigidly attached to its corresponding tape reel  204 ,  206 , and mates with an aligned, complementary gear provided in the drive mechanism. A motor in the drive mechanism rotates one of the reels acting as a tape pickup reel, while another motor in the drive mechanism brakes the feed reel under control of a motors controller operating in a manner well known in the tape transport art. Attached to each drive gear  212 ,  214  is a brake mechanism  216 ,  218  which locks the associated reel from inadvertent rotation when a cartridge including the subassembly  200  is removed from the tape drive unit. Most preferably, each brake mechanism is actuated when the door  210  is slid to an open position which occurs when the subassembly (and cartridge) are fully loaded into a tape drive unit. 
     FIGS. 9,  10  and  11  show the subassembly  200  being inserted into a DLT-style plastic tape cartridge  300 . The cartridge  300  includes a base  302  and a cover  304 . As shown in FIG. 9, the cartridge  300  includes a series of drive orientation notches  306 , drive registration datum points  308 , a door assembly  310  cooperating with door  210 , a set of drive docking notches  312 , a write protect switch  314 , a bar code label area  316 , and a manufacturer&#39;s brand/label area  318 . The write protect switch can be moved to enable or disable the ability of the drive unit to write onto the magnetic media  208  within the cartridge  300 . The bar code label area provides a standardized location for bar codes of the type that is automatically scanned by a tape cartridge library system to identify each cartridge. The manufacturers&#39; label area enables the cartridge manufacturer to install a desired identification label or logo. The drive orientation notches are used by the drive unit to grab hold of the cartridge  300  and force it downwards into a fully loaded position within the tape drive. They also provide a “flipped notch” function to prevent the cartridge  300  from being inserted upside down into the drive unit and thereby protect the fragile head components of the drive unit from being damaged. The drive registration features are most preferably exposed metal features of the chassis  202  which protrude from the cartridge enclosure  300 . These features are precisely machined and establish accurate reference datum points for head assembly positioning and also ensure that the cartridge is aligned repeatably inside the drive unit for accurate media interchange, as mentioned above. The drive docking notches are used by the drive unit and other robotic tape cartridge handling mechanisms to securely grip and manipulate the cartridge  300 . FIGS. 12A,  12 B,  12 C and  12 D show other views of the cartridge  300 . FIG. 12A is a top plan view and FIG. 12D is a bottom plan view. FIGS. 12B and 12C provide a right side elevational view and a rear elevational view, respectively. 
     Other embodiments are within the scope of the following claims. For example, although only DLT and 3480 style cartridges have been described herein, it will be understood that the universal subassembly could also be used with other cartridge styles, such as Linear Tape-Open (LTO), as well.