Patent Publication Number: US-6215614-B1

Title: Cartridge loading method and apparatus

Description:
This is a divisional of application Ser. No. 09/387,608 filed on Aug. 31, 1999 now U.S. Pat. No. 6,108,161, which is a divisional of Ser. No. 09/103,436 filed on Jun. 24, 1998 now U.S. Pat. No. 6,057,980. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a cartridge loading device with a novel cartridge receiving and indexing scheme. 
     BACKGROUND ART 
     Cartridge loading devices for use in a media system can be highly complex and expensive, particularly due to the accurate repeatability required in locating the cartridge with respect to the read/write head. In particular, it is desirable that the cartridge be located within +/−1 minute of skew (side-to-side of cartridge); +/−0.0005 inch of tilt (front-to-rear of cartridge); +/−0.6 degrees of wrap (+/−0.005 penetration onto read/write head); with a load time of less than 500 milliseconds. 
     In the prior art, the tape is usually lifted away from the read/write head by blowing air against the tape to lift it away from the head during high speed tape functions, such as rewind or fast-forward. However, the structure required for such pneumatics is typically large and heavy, and therefore expensive. Accordingly, it is desirable to provide an improved tape lifter function without pneumatics and without posing risk of damage to the tape. It is also desirable that the tape be engaged with or disengaged from the read/write head within 70 milliseconds by a repeatable tape lifter function. 
     It is also desirable to provide a means for accurately engaging the reel motors which drive the cassette tape reels, without backlash. Additionally, the read/write head must be protected from robotic or manual loading impacts when the cartridge is inserted into position within the loading device. 
     Preferably, such functions would be provided within a load/drive unit which may be packaged in a small area, such as a 5¼ inch form factor drive. 
     DISCLOSURE OF INVENTION 
     The present invention improves upon the prior art and achieves the above-stated design criteria by providing an improved cartridge loading device with a novel cartridge registration scheme which accurately locates the cartridge while preventing loading impacts, provides an accurate and repeatable tape lifter function, and provides repeatable reel motor engagement without backlash, while minimizing product cost. 
     Specifically, one aspect of the invention provides an apparatus for moving a tape cartridge with respect to a read/write head in a media system, wherein the tape cartridge includes a tape stored on tape reels. The apparatus includes a housing having a base, and a plurality of flexures extending substantially perpendicularly with respect to the base and having first and second ends. The first ends are attached to the housing. A deck is configured for holding a tape cartridge with the tape exposed at one end of the deck. The deck is attached to the second ends of the flexures. The flexures are sufficiently rigid to support the deck and sufficiently flexible to allow movement of the deck with respect to the base for moving the tape toward and away from the read/write head. 
     Preferably, a movable shuttle is positioned within the deck for moving the tape cartridge with respect to the deck. A shuttle interlock mechanism is positioned between the deck and the shuttle for selectively locking the shuttle with respect to the deck to prevent damage to the read/write head from loading impacts when cartridges are inserted. 
     The tape cartridge preferably includes primary, secondary, and tertiary locating features, and the cartridge loading device includes a plurality of springs for providing a preload against each of such locating features. Also, preferably a head cleaner brush is actuated by a rotary drum with a helical cam path for cleaning the read/write head during loading and unloading of the cartridge. 
     Preferably, a vertically movable motor plate is positioned adjacent the deck and includes first and second reel motors mounted thereon for driving the tape reels. A substantially flat flexible flexure member is connected at opposing ends to the deck and motor plate, respectively, to allow relative vertical movement of the motor plate and deck while preventing reel motor backlash. The flexure member is preferably a substantially H-shaped steel structure. 
     Another aspect of the invention provides a method of engaging a tape cartridge with a read/write head in a media system. The method includes: a) receiving the tape cartridge within a movable shuttle which is locked in a position spaced from the read/write head; b) unlocking the shuttle; and c) moving the shuttle toward the read/write head to engage the tape cartridge with the read/write head. The tape cartridge includes a three-point primary datum, a two-point secondary datum, and a one-point tertiary datum, and the method further includes providing a spring load against each such datum point. 
     Accordingly, an object of the invention is to provide a structure and method for repeatedly locating a tape cartridge with respect to a read/write head in a media system. 
     Another object of the invention is to provide a tape lifter function which does not require pneumatics, and does not risk damage to the media. 
     A further object of the invention is to provide a means of accurately engaging the reel motors of a media system without backlash. 
     Still another object of the invention is to provide a cartridge loading device which protects the read/write head From robotic and manual loading impacts. 
     A further object of the invention is to provide a cartridge loading device which includes structure for cleaning the read/write head on each load/unload cycle. 
     The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 shows a partially exploded perspective view of a shuttle in accordance with the present invention; 
     FIG. 2 shows a perspective view of a motor plate assembly in accordance with the present invention; 
     FIG. 3 shows a perspective view of a cam plate secured to a housing in accordance with the present invention; 
     FIG. 4 shows a perspective view of vertical flexures secured to the housing base in accordance with the present invention; 
     FIG. 5 shows a perspective view of a movable deck assembly in accordance with the present invention; 
     FIG. 5 a  shows a cut-away perspective view of an interior rear corner of the deck of FIG. 5; 
     FIG. 5 b  shows a cut-away perspective view of an opposing interior dear corner of the deck of FIG. 5; 
     FIG. 6 shows a front perspective view of the cartridge loading device in accordance with the present invention; 
     FIG. 7 shows a rear perspective view of the cartridge loading device in accordance with the invention; 
     FIG. 8 shows a rear perspective view of the cartridge loading device of FIG. 7 including a read/write head; 
     FIG. 9 shows a front view of the read/write head of FIG. 8 with the tape thereon; 
     FIG. 10 shows a perspective view of the read/write head of FIG. 7; 
     FIGS. 11 a - 11   g  show schematic plan views of the cam plate in sequentially rotated positions; 
     FIG. 12 shows a perspective view of a tape cartridge for use with the present invention; and 
     FIG. 13 shows a reverse perspective view of the tape cartridge of FIG.  12 . 
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Referring to FIGS. 6-8, a cartridge loading device  10  is shown in accordance with the present invention for receiving a tape cartridge, such as that shown in FIGS. 12 and 13. The various components of the cartridge loading device are shown in FIGS. 1-5 and  9 - 11 . The structure of the cartridge loading device  10  will be described in a cartridge loading sequence for loading the cartridge  12  for engagement with the read/write head assembly  14  shown in FIGS. 9 and 10 (specifically item  126  in FIG.  10 ). 
     As shown in FIGS. 12 and 13, the tape cartridge  12  includes drive reels  16  which hold a tape  18  (shown in FIG. 9) within the tape cartridge  12 . The cartridge  12  includes a tape door  20  for covering the tape  18 , and a plurality of cartridge ID recesses  22 . 
     The cartridge  12  also includes primary datums A 1 , A 2 , A 3 ; secondary datums B 1 , B 2 ; and a tertiary datum C 1  for properly locating the tape cartridge  12  with respect to the read/write head  126 . 
     The first step in loading the cartridge  12  is to insert the cartridge  12  into the drive opening  24 , shown in FIG.  6 . The insertion of the cartridge  12  into the drive opening  24  may be performed by a robotic arm with a hand assembly for manipulating the cartridge  12 , or it may be manually inserted. As the cartridge  12  is inserted, a keying feature  26  (shown in FIG. 13) is engaged to verify correct orientation of the cartridge  12 . 
     As the cartridge  12  is further inserted, a cartridge-in-slot sensor  28 , shown in FIG. 1, is tripped so that the storage library system knows that a cartridge has been inserted so that the robotics do not attempt to load another cartridge. Detent arms  30 , shown in FIG. 1, then engage the recesses  32  of the cartridge  12 , shown in FIG. 13, so that the cartridge  12  is grasped by the shuttle assembly  34 , shown in FIG. 1, for manipulating the cartridge  12 . 
     The cartridge seated slide  44 , shown in FIG. 1, is then engaged by the cartridge, and an optical sensor is tripped by movement of the slide  44 . At this point, the loader motor  46 , shown in FIG. 4, begins rotation of the cam plate  48 , shown in FIG.  3 . The can position sensor  50 , shown in FIG. 6, then changes state. 
     With the detent arms  30  engaged in the recesses  32  of the cartridge  12 , as described above, the cartridge  12  is secured in the shuttle assembly  34 , which is movable within the deck  54 , shown in FIG. 5. A shuttle interlock feature  61 , shown in FIGS. 1 and 5, is provided for selectively locking the shuttle  34  to the deck  54  for preventing damage to the read/write head  14  and tape if a robotic arm assembly were to inadvertently slam a cartridge into the shuttle  34 . As the detent plates  56 , shown in FIG. 1, begin to move, the shuttle interlock pin  58  is disengaged from the interlock notch  60 , shown, in FIG. 5, by means of an interlock cam  57  in the detent plate  56 , driving the interlock actuator pin  59  which pivots the interlock arm  61  about the shuttle pin  63  for disengagement from the interlock notch  60 . 
     Movement of the detent plate  56  permits the detent arm pin  62  to move within the slot  64 , shown in FIG. 1, which actuates locking and unlocking of the detent arms  30  for loading and unloading the cartridge. As shown in FIG. 1, the detent arm pin  62  is locked within the slot  64  to lock the cartridge detent arms  30  to secure the cartridge (not shown) within the shuttle  34 . 
     As shown in FIG. 1, the detent plates  56  are engaged with a center stable spring  66  for allowing the shuttle assembly  34  to move in and out with respect to the deck  54 . A slot  64  in the cam plates  56  provide a locking and release function for the detent arms  30  via the detent arm pin  62 . The detent plates  56  also provide a preloading function or holding the cartridge on the B 1  and B 2  datums, shown in FIGS. 5 a  and  5   b.    
     The shuttle  34  then pulls the cartridge  12  approximately 1 inch into the deck  54 . During this motion, the head cleaner mechanism  68 , shown in FIG. 4, swipes across the read/write head  126 . The head cleaner mechanism  68  includes a head cleaner linear slide  72  which is actuated by the rotary drum  74  with a helical path  76  therein. The rotary drum  74  is rotated by the motor  46 . The head cleaner mechanism  68  moves the cleaning brush  70  across the read/write head  126  once during each load/unload sequence. During this 1 inch movement of the shuttle, the door opener  36 , shown in FIG. 1, opens the cartridge door  20  via the cam slot  40 , shown in FIG. 5, and cam pin  42 , shown in FIG.  1 . 
     During the one inch shuttle motion, the cartridge door opener  36 , shown in FIG. 1, engages the cartridge  12  to begin opening the cartridge door  20 , shown in FIG.  13 . The cartridge door opener  36  is actuated laterally by the door opener cam  38 , shown in FIG. 5, which includes a cam slot  40  for guiding the cam pin  42 , shown in FIG. 1, which is connected to the door opener  36 . When the door opener  36  is fully actuated at the end of the one inch motion, the cartridge door  20  is opened, and the tape within the cartridge  12  as exposed for read/write functions. 
     The cam position sensor  50 , shown in FIG. 6, then chances state again, which triggers a sensor check to verify that the cartridge was not lost during the loading motion. After verification that the cartridge is present, the loader motion continues. 
     Next, the cartridge datum C 1 , shown in FIG. 13, which is the tertiary datum, engages an alignment slot C on the moving deck  54 , shown in FIG. 5 a.    
     The B 1  and B 2  datums of the cartridge  12 , shown in FIG. 13, then contact the alignment features b 1 , b 2  on the moving deck  54 , shown in FIG. 5 a  and  5   b . The detent plates  56 , shown in FIG. 1, move along with the cartridge  12 , and the spring  66  corresponding with each detent plate  56  preloads the cartridge  12  against the datums b 1 , b 2 . 
     At this point, the motor plate assembly  80 , shown in FIG. 2, is moved vertically toward the deck  54 . The motor plate assembly  80  includes reel motors  82  for driving the couplings  84 , which drive the tape reels  16 , shown in FIG. 12. A substantially flat, generally H-shaped flexible flexure member  86 , shown in FIG. 2, secures the motor plate assembly  80  to the deck  54 . The first end  88  of the flexure member  86  is connected to the motor plate assembly  80 , and the second end  90  is connected to the deck  54 . This configuration allows relative vertical movement of the motor plate assembly  80  and deck  54  while aligning the reel motors to the tape reels  16  and preventing reel motor backlash. The flexure member  86  is preferably a thin stainless steel component to provide sufficient bending flexibility to allow vertical movement of the motor plate assembly  80  with respect to the deck  54 , while preventing torsional flexion as the reel motors  82  rotate the couplings  84 . As the motor plate assembly is lifted up toward the deck  54 , the three datum pads  92 ,  94 ,  96  contact the deck  54  in order to control engagement of the couplings  84  with the tape reels  16 . The datum pads  92 ,  94 ,  96  are shown in FIG.  2 . Simultaneously, the cartridge identification sensors  98 , shown in FIG. 2, engage the cartridge ID recesses  22 , shown in FIG. 12, to verify the model of cartridge inserted. 
     As the couplings  84 , shown in FIG. 2, engage the tape reels  16 , shown in FIG. 12, spool locks are released. The cartridge  12  is lifted onto the a 1 , a 2  and a 3  datums of the moving deck  54 , shown in FIGS. 5 a ,  5   b  and  7 . The cartridge is preloaded against the a 1 , a 2 , and a 3  datums by spring-loaded plungers  100 , shown in FIG. 2, extending from the motor plate assembly  80 . 
     As shown in FIG. 2, the motor plate assembly  80  includes a motor plate preload arm  102  pivotally connected to the motor plate assembly  80  at the pivot joint  104 , and including a preload spring  106  for preloading the datums  92 ,  94 ,  96  against the deck, spring loading the plungers  100  against the cartridge  12  and reel motor couplings  84  against the cartridge reel  16 . Pivotal movement of the motor plate preload arm  102  is provided by engagement of the pin  108  in the elevator cam path  110 , shown in FIG.  3 . 
     Accordingly, the motor plate assembly provides a platform for accurately mounting the motors  82 , provides a location for the cartridge identification sensor  98 , provides a preload to the cartridge shell via spring-loaded plungers  100 , controls the engagement depth of the couplings  84  into the cartridge  12 , and preloads the entire drive mechanism against the deck and the cartridge through the preload arm  102 . 
     Again, the cam position sensor  50 , shown in FIG. 6, changes state at the detented unwrapped position, and motion stops. The reel motors  82 , shown in FIG. 2, take up slack between the tape spools  16  inside the cartridge  12 , and locate the middle of the tape. 
     Upon command, the deck  54  moves forward approximately 0.16 inches to wrap the tape onto the read/write head assembly  14 , as shown in FIG.  9 . The moving deck  54  is mounted on four vertical flexures  112 , shown in FIG. 4, which extend substantially perpendicular with respect to the base  114  of the housing  116 . The flexures  112  have first and second ends  118 , 120 , respectively, and are attached at the first end  118  to the base  114 . The second end  120  of each flexure  112  is attached to the deck  54 . The flexures  112  are sufficiently rigid in all the degrees of freedom (up-down, side-to-side) except for motion normal to their plane of attachment (which is a vertical plane as viewed in FIG. 4) to support and maintain alignment of the deck  54 , and sufficiently flexible in the direction normal to their plane of attachment for allowing movement of the deck  54  with respect to the base  114  for moving the cartridge  12  toward and away from the read/write head  14 . The flexures  112  are preferably thin, stainless steel components. This structure permits the deck  54  to move in and out without losing alignment to the read/write head  126 . 
     The vertical flexures  112  are operative to provide a tape lifter function or tape wrap function which allows the tape  18 , shown in FIG. 9, to be moved into contact with the read/write head assembly  14  for read/write operations and out of contact with the read/write head assembly  14  for high speed tape operations, such as fast-forward and rewind. 
     The vertical flexures  112  are supported on the base plate assembly  122  (which includes the base  114 ), shown in FIG.  4 . The base plate assembly  122  is considered to be part of the housing  116 . The base plate assembly  122  contains the drive motor  46 , the idler cross-shaft  124 , and the head cleaner assembly  68 . 
     As shown in FIGS. 8-10, the read/write head  126  is positioned at the rear of the cartridge loading device  10  so that the tape  18  may be exposed against the read/write head assembly  14  when the cartridge is advanced to the rear of the cartridge loading device  10 . As viewed in FIG. 9, the head  126  is movable vertically on guide shafts  128 , which ride on bearings  130 . The head assembly  14  includes a position encoder  134 , flex circuits  136 ,  138 ,  140 , a coil actuator  142 , and skew adjustment features  144 , 146 . 
     As the deck  54  continues to move, it contacts a hard stop on the read/write head assembly  14 , which sets the tape wrap angle and penetration. Again, the cam position sensor  50  of FIG. 6 changes state. 
     In this position, read/write functions can now be performed by the read/write head assembly  14  on the tape  18 , and the moving deck  54  can be toggled back and forth between the wrap and unwrap position to provide a tape lifter function. 
     The cartridge unload process occurs in the reverse order of the above-defined process. 
     Referring to FIGS. 3 and 11 a - 11   g , the motions of the motor plate assembly  80 , moving deck  54 , and shuttle  34  are all defined by the cam paths  110 ,  150  and  148 , respectively, formed in the cam plate  48 , shown in FIG.  3 . The elevator cam path  110  engages the motor plate pin  108  shown in FIG. 2, the shuttle cam path  148  engages the shuttle pin  152 , shown in FIG. 1, and the deck cam path  150  engages the deck pin  154 , shown in FIG.  5 . 
     The sequence of movement of the respective pins within the three cam paths is illustrated sequentially in FIGS. 11 a - 11   g . In FIG. 11 a , each pin  108 ,  152 ,  154  is at the end of its respective cam path  110 ,  148 ,  150 . In this position, the cartridge loading device  10  is in the open position and the detent arms  30  are unlocked for receiving the cartridge  12 . After 20° of clockwise rotation to the position shown in FIG. 11 b , the shuttle pin  152  engages the radial portion  156  of the shuttle cam path  148  to actuate movement of the shuttle  34 . As shown in FIGS. 11 b - 11   d , in this cam plate rotational range of 71.3°, the shuttle pin  152  is retained within the radial portion  156  of the shuttle cam path  148 , which causes the 1 inch movement of the shuttle  34 . 
     In the 60 20   of rotational movement between the positions of FIGS. 11 d  and  11   e , the movement of the pin  108  within the elevator cam path  110  causes the motor plate assembly  80  to rise vertically for engagement with the deck  54 . 
     The movement represented between FIGS. 11 e  and  11   f  of the pin  108  within the elevator cam path  110  compresses the motor plate preload arm spring  106  to load the motor plate assembly  80  against the datums  92 ,  94 ,  96 . 
     The movement represented between FIGS. 11 f  and  11   g  is 40° of rotational movement. In this range, movement of the deck pin  154  within the deck cam path  150  causes tape lifter movement of the deck of approximately 0.160 inch to wrap the tape against the read/write head  14 . The vertical flexures  112 , shown in FIG. 4, flex to allow such movement. 
     All such movement is actuated by the single motor  46 , shown in FIG. 4, which drives rotation of the cam plate  48 , shown in FIG.  3 . 
     The invention also provides a method of engaging a tape cartridge  12  with a read/write head  14  in a media system, comprising: a) receiving the tape cartridge  12  within a movable shuttle  34  which is locked in a position spaced from the read/write head assembly  14 ; b) unlocking the shuttle  34 ; c) moving the shuttle  34  toward the read/write head assembly  14  to position the tape cartridge  12  against the primary, secondary and tertiary datums in the deck; d) raising the motor plate to engage the reel motors with the cartridge reels; e) bringing the reel motion and tape tension under servo-control; and f) moving the deck with the shuttle and cartridge an additional distance to engage the tape  18  in the cartridge with the read/write head  126 . The tape cartridge  12  includes a three-point primary datum A 1 , A 2 , A 3 ; a two-point secondary datum B 1 , B 2 ; and a one-point tertiary datum C 1 , and the method further comprises providing a spring preload against each such datum. 
     While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.