Abstract:
A total axis, self adjusting pass-through port for use with library storage modules (LSM) of different heights and placed at different angles and distances. The pass-through port may include one or more hinged library storage module terminal ports, telescopic guide rails, and one or more ball joints associated with the guide rails to facilitate the transport of storage medium from a sending LSM to a receiving LSM when the sending and receiving LSM are placed at non-standard angles, have different radii of curvature, different heights, or are placed at non-standard distances from one another.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention is directed to a total axis, self adjusting pass-through port. Specifically, the present invention is directed to a pass-through port for use with library storage modules that facilitates various angles between the library storage modules, varying distances between the library storage modules, and varying heights of the library storage modules. 
     2. Description of Related Art 
     The use of library storage modules is generally known in the art. Library storage modules allow for the storage and retrieval of thousands of magnetic tape cartridges for use with computing systems. A typical library storage module is described, for example, in U.S. Pat. No. 4,864,511 issued to Moy et al., which is hereby incorporated by reference in its entirety. 
     It is also known to use pass-through ports to facilitate the passing of magnetic tape cartridges from one library storage module to another. FIG. 1 is a diagram illustrating the prior art pass-through port. As shown in FIG. 1, the pass-through port is comprised of multiple storage cells  132  adapted to ride upon a carriage  384  for transference between the library storage modules. The array of storage cells  132  are spring-loaded upon a pivot  386  attached to the carriage  384 , and includes a pair of cam followers  388  adapted to follow a cam surface  390  from one library storage module to the other. The carriage  384  is further coupled to a lead screw  392  by a nut (not shown), which pulls the carriage  384  along the lead screw  392 . In order to guide the carriage  384  along the lead screw  392 , the carriage  384  is further coupled to a pair of guide rods  396 . 
     When a drive motor  398  rotates the lead screw  392 , the carriage  384  is pulled along the lead screw  392  by the nut  394 , but the pivoting array of cells  132  following the cam surface  390  enable the cells  132  to be positioned advantageously for incorporation with either library storage module. That is, the array of cells  132  is initially positioned within one library storage module in a manner similar to each of the other storage cells  132  mounted upon the outer housing of the library storage module for access by a robotic arm. Thereafter, upon rotation of the lead screw  392  by the motor  398 , the array of cells  132  are rotated, as shown by the dashed arrows in FIG. 1, to a position within the interconnected library storage module for access by its respective robotic arm. The carriage  384  does not enter the arm swing space so that motions of the robotic arm may continue during rotation. 
     FIGS. 2 and 3 show another prior art pass-through port in which, instead of guide rods  396 , the carriage  384   a  is guided by a simple groove  395  and pin  397  arrangement which maintains its stability. Like the pass-through port  382  shown in FIG. 1, the pass through port  382   a  includes a pair of cam surfaces  390   a  and  390   b  each of which are referenced to their respective library storage modules. A lead screw  392   a  and nut  394   a  arrangement provides the motive force for translating the carriage  384   a  between the library storage modules. A torsion spring  384  is used to pivot the cells  132  just as in the pass-through port  382  of FIG.  1 . 
     These prior art pass-through ports are limited, however, to a specific angle between library storage modules, a specific distance between library storage modules, and library storage modules that are of the same height. As a consequence, the prior art pass-through ports are very difficult to align due to variations in all directions from one library storage module to another. Thus, there is a need for new technology to allow a library storage module to pass tape cartridges from itself to other dissimilar library storage modules or library modules placed in different positions. 
     SUMMARY OF THE INVENTION 
     The total axis, self adjusting pass-through port according to this invention includes a tape carrier attached to a carriage for movement between two library storage modules (LSMs). The carriage is further coupled to a drive belt and guide rail assembly. The drive belt moves the carriage from one LSM terminal port, associated with a sending LSM, to another, associated with a receiving LSM, when driven by the drive motor. The guide rail assembly guides the carriage along the path between LSM terminal ports. One or both of the LSM terminal ports may be hinged to the guide rail assembly to facilitate varying angles between the LSMs. 
     The LSM terminal ports are two separate devices that may be mounted on respective LSMs and may be mounted in various positions relative to one another. Thus, the use of the two separate LSM terminal ports helps to facilitate the placement of LSMs in various positions relative to one another and also helps to facilitate the use of LSMs having different radii. 
     The tape carrier includes a cam follower which follows cam surfaces in the LSM terminal ports as the tape carrier is moved from one LSM terminal port to the other LSM terminal port, and vice versa. The cam follower engaging the cam surfaces provides a mechanism by which the tape carrier is rotated about a pivot such that the tape carrier may be rotated into a position relative to the LSMs that allows an associated robotic arm to retrieve tape cartridges present in the tape carrier. 
     The guide rail assembly may be comprised of telescopic guide rails having a master guide rail and a slave guide rail which is configured such that it may slide in and out of the master guide rail to thereby provide a telescopic motion of the guide rails. The use of telescopic guide rails in the guide rail assembly allows for varying distances between the LSM terminal ports, and hence varying distances between the LSMs. The varying distances may be a-result of varying angles between the LSMs, varying heights between the LSMs, placement of the LSMs and the like. 
     As a further feature, the guide rail assembly may include a ball joint for attachment of the guide rail assembly to one or more of the LSM terminal ports. The ball joint provides for three degrees of rotation about an attachment point. Thus, by using the ball joint, the LSM terminal ports may be positioned in varying positions relative to one another. The combination of the ball joint, telescoping guide rails, and the hinged LSM terminal port provides for a tape cartridge pass-through port that is capable of facilitating varying heights, angles, and distances between LSMs. 
     In addition, the LSM terminal ports may include orientation devices which help to orient the tape carrier so that the tape carrier is in a proper position when engaged with the LSM terminal port. When the orientation devices contact an orientation device engagement device on the tape carrier, the engagement between the two devices causes the tape carrier to orient to a position from which a robotic arm associated with the receiving LSM may retrieve tape cartridges. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein like numerals identify like elements, and wherein: 
     FIG. 1 is a diagram of a prior art pass-through device; 
     FIGS. 2 and 3 are diagrams of another prior art pass-through device; 
     FIG. 4 is a diagram of the pass-through port device according to one embodiment of the present invention; 
     FIG. 5 is a diagram of the pass-through port device of FIG. 4 from an angle slightly below the pass-through port device; 
     FIG. 6 is a diagram illustrating the telescoping guide rails of one embodiment of the invention; 
     FIG. 7 is a diagram illustrating additional features of the pass-through port device according to the invention; 
     FIGS. 8A-D illustrate the movement of the tape cartridge holder as it moves from one library storage module to another library storage module; 
     FIG. 9 illustrates how the pass-through port device of the present invention may be utilized with libraries of different heights; and 
     FIG. 10 illustrates how the pass-through port device of the present invention may be utilized with library storage modules positioned at different angles and library storage modules having different radii. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 4 is a diagram of the pass-through port device  400  according to one embodiment of the present invention. As shown in FIG. 4, the pass-through port device  400  includes a tape carrier  410  attached to a carriage  440  for movement between two library storage modules (LSMs). The tape carrier  410  is spring-loaded upon a pivot  430  attached to the carriage  440 . 
     The carriage  440  is further coupled to a drive belt  470  and guide rail assembly  450 . The drive belt  470  moves the carriage from one LSM terminal port  420  to another when driven by the drive motor  490 . The guide rail assembly  450  guides the carriage  440  along the path between LSM terminal ports  420  and  425 . 
     The LSM terminal ports  420  and  425  are two separate devices that may be mounted on respective LSMs and may be mounted in various positions relative to one another. Thus, the use of the two separate LSM terminal ports  420  and  425  helps to facilitate the placement of LSMs in various positions relative to one another and also helps to facilitate the use of LSMs having different radii. 
     Although FIG. 4 shows the pass-through port device  400  as having a drive belt  470  to move the carriage  440  from one LSM terminal port  420  to the other LSM terminal port  425 , the invention is not limited to such an embodiment. Rather, as described in the incorporated U.S. Pat. No. 4,864,511 and shown in FIGS. 1 and 2, a nut and screw assembly may be utilized for moving the tape carrier  410  between LSM terminal ports  420  and  425 . Other equivalent driving mechanisms may be employed to drive the taped carrier  410  between LSM terminal ports  420  and  425  without departing from the spirit and scope of the invention. 
     The LSM terminal port  420  is hinged about the hinge axis  480  such that the LSM terminal port  420  may rotate about the vertical axis in a horizontal motion. This hinge allows the LSM terminal port  420  to be placed in various angles relative to LSM terminal port  425 . The LSM terminal ports  420  and  425  are mountable on a LSM such that LSM terminal port  420  may be associated with a first LSM and LSM terminal port  425  is associated with a second LSM. 
     Although the preferred embodiment shown in FIG. 4 utilizes one hinged LSM terminal port  420  and one non-hinged LSM terminal port  425 , the invention is not limited to such an embodiment. To the contrary, both the LSM terminal ports  420  and  425  may be hinged or non-hinged. 
     FIG. 5 shows the pass-through port device  400  from a view point slightly below the pass through port device  400 . As shown in FIG. 5, the tape carrier  410  includes at least one cam follower  510  on the bottom surface of the tape carrier  410 . The cam follower follows the cam surfaces  520  as the tape carrier  410  is moved from one LSM terminal port  420  to the other LSM terminal port  425 , and vice versa, by the carriage  440  being driven by the drive motor  490  and the drive belt  470 . Although only one cam follower  510  is shown in FIG. 5, a plurality of cam followers  510  may be used without departing from the spirit and scope of the invention. 
     The cam follower  510  engaging the cam surfaces  520  provides a mechanism by which the tape carrier  410  is rotated about the pivot  430 . In this way, the tape carrier  410  may be rotated into a position relative to the LSMs that allow an associated robotic arm to retrieve tape cartridges present in the tape carrier  410 . 
     In order to ensure that the cam follower  510  engages the cam surfaces  520  as the tape carrier  410  moves between LSM terminal ports  420  and  425 , the preferred embodiment shown in FIGS. 4 and 5 makes use of one hinged and one non-hinged LSM terminal port  420 ,  425 . To further ensure proper positioning of the tape carrier  410  as it travels between LSM terminal ports  420  and  425 , hinge restriction devices may be employed to limit the angle at which the LSM terminal ports  420  and  425  may be placed relative to one another. Additionally, the LSM terminal ports  420  and  425  may be configured in such a way that a large range of angles between the LSM terminal ports  420  and  425  are accommodated. 
     While the embodiment shown in FIG. 5 depicts the cam follower  510  as being on a bottom surface of the tape carrier  410 , the invention is not limited to such an arrangement. Rather, the cam follower  510  may be placed on any surface of the tape carrier  410  as long as the cam follower is able to follow a cam surface  520  for rotation of the tape carrier  410 . Thus, for example, if a cam surface  520  is mounted above the tape carrier  410 , the cam follower  510  may be positioned on a top surface of the tape carrier  410 . 
     The drive motor  490  drives the drive belt  470  based on control signals sent to the drive motor  490 . These signals may be sent, for example, by a computer associated with an LSM (either the sending or receiving LSM), a switch operated by an operator or a robotic arm, or the like. Any means by which a control signal may be sent to the drive motor  490  is intended to be within the spirit and scope of the present invention. 
     When the drive motor  490  drives the drive belt  470 , the carriage  440  is pulled along the guide rail assembly  450  between the LSM terminal ports  420 . As the carriage  440  moves from one LSM terminal port  420  to the other  425 , for example, the cam follower  510  mounted on the tape carrier  410  follows the cam surfaces  520  in the LSM terminal ports  420  and  425 . In this way, the cam follower  510  causes the tape carrier  410  to rotate from a first position in which an opening in the tape carrier  410  is aligned with the first LSM, to a position in which the opening in the tape carrier  410  is aligned with the second LSM. 
     Thus, with the present invention as shown in FIGS. 4 and 5, when a tape cartridge is to be transported from one LSM to another, the robotic arm associated with the sending LSM loads the tape cartridge into the tape carrier  410 . A control signal is sent to the drive motor  490  which pulls the carriage  440  using the drive belt  470 . As the tape carrier  410  traverses the path between LSM terminal ports  420  and  425 , the cam follower  510  moves along the cam surfaces  520 . 
     While the cam follower  510  moves along the cam surfaces  520 , the tape carrier  410  is caused to rotate about the pivot  430 . As a result, the tape carrier  410  is placed in a proper position relative to the receiving LSM such that a robotic arm associated with the receiving LSM is able to remove the tape cartridge from the tape carrier  410 . 
     FIG. 6 is a diagram illustrating features of a further embodiment of the invention. As shown in FIG. 6, the guide rail assembly  450  may be comprised of telescopic guide rails  600  having a master guide rail  610  and a slave guide rail  620 . The slave guide rail  620  is configured such that it may slide in and out of the master guide rail  610  to thereby provide a telescopic motion of the guide rails  600 . 
     The use of telescopic guide rails  600  in the guide rail assembly  450  allows for varying distances between the LSM terminal ports  420  and  425 , and hence varying distances between the LSMs. The varying distances may be a result of varying angles between the LSMs, varying heights between the LSMs, placement of the LSMs and the like. 
     As a further feature, the guide rail assembly  450  may include a ball joint  630  for attachment of the guide rail assembly  450  to one of the LSM terminal ports  425 , for example. The ball joint  630  provides for free motion about three axes of an attachment point. Thus, by using the ball joint  630 , the LSM terminal ports  420  and  425  may be positioned in varying positions relative to one another. The combination of the ball joint  630 , telescoping guide rails  600 , and the hinged LSM terminal port  420  provides for a tape cartridge pass-through port  400  that is capable of facilitating varying heights, angles, and distances between LSMs. 
     FIG. 7 is a diagram of the guide rail assembly  450  shown in FIG. 6 in conjunction with the carriage  440  and the LSM terminal port  425 . As shown in FIG. 7, the carriage  440  is capable of movement along the telescoping guide rails  600  while the ball joint  630  provides a mechanism by which the LSM terminal port  425  may be positioned at an angle relative to the LSM terminal port  420 . 
     Additional features of the invention shown in FIG. 7 include the opening  720  which is configured to receive the pivot  430 , and orientation devices  730  which help to orient the tape carrier  410  so that the tape carrier  410  is in a proper position when engaged with the LSM terminal port  420  or  425 . Although the opening  720  is shown as being circular, any type of opening may be used without departing from the spirit and scope of the invention. While the orientation devices  730  are shown as being tapering in shape, the invention may make use of orientation devices  730  having any suitable shape for orienting the tape carrier  410 . 
     FIGS. 8A-D depict the tape carrier  410  at various stages during the transport of a tape cartridge from LSM terminal port  420  to LSM terminal port  425 . As shown in FIG. 8A, the tape carrier  410  may be attached to the carriage  440  by way of a free ball joint  810 . The tape carrier  410  may further include a bias spring  820  for returning the tape carrier  410  to a predetermine position, and an orientation device engagement device  830  for engaging the orientation devices  730 . Although a free ball joint  810  is shown in FIGS. 8A-D, the invention may make use of any securing device for securing the tape carrier  410  to the carriage  440  so long as the securing device allows for rotation of the tape carrier  410 . 
     As shown in FIG. 8A, the tape carrier  410  starts in an engaged position with a first LSM associated with LSM terminal port  420 . As the tape carrier  410  moves from the LSM terminal port  420  to the LSM terminal port  425 , the tape carrier  410  is rotated about the pivot  430  by way of the free ball joint  810  and the cam follower  510  following the cam surfaces  520  (FIGS.  8 B and  8 C). As the tape carrier  410  engages the LSM terminal port  425 , the tape carrier  410  is rotated by way of the cam follower  510 , cam surface  520 , and the engagement of the orientation devices  730  with the orientation device engagement device  830 , so that the tape carrier  410  is in a proper position relative to the receiving LSM, for tape cartridge removal by an associated robotic arm (FIG.  8 D). 
     FIG. 9 illustrates how the pass-through port device  400  of the present invention may be used with LSMs having varying heights. As shown in FIG. 9, the pass-through port device  400  is positioned on a top surface of two LSMs  1001  and  1002 . LSM  1001  has a height H 1  and LSM  1002  has a height H 2  with H 1  being greater than H 2 . Thus, as shown in FIG. 9, the pass-through port device  400  of the present invention may be used to transport tape cartridges to and from LSMs having varying heights. 
     FIG. 10 illustrates how the pass-through port device  400  of the present invention may be used with LSMs positioned at various angles. As shown in FIG. 10, LSM  1001  has a radius R 1  and LSM  1002  has a radius R 2  which is smaller than radius R 1 . As a result, LSM  1002  is positioned at an angle difference θ from LSM  1001 . However, due to the novel features of the present invention, the pass-through port device  400  is capable of accommodating the angle difference θ in position between the LSMs  1001  and  1002  as shown in FIG.  10 . 
     While the above embodiments are described with reference to a tape cartridge pass-through port apparatus, the invention is not limited to tape cartridges. Rather, any type of storage medium may be transported using the present invention. For example, the storage medium may be digital versatile disks, floppy disks, magnetic tape reels, ROM or RAM cartridges, ZIP disks, removable hard drives, and the like. 
     The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.