Patent Publication Number: US-11649115-B2

Title: Apparatus and methods for automated picking of items

Description:
This application is a Continuation of U.S. application Ser. No. 15/893,066 filed Feb. 9, 2018, allowed, which is a Continuation of U.S. application Ser. No. 14/859,778, filed Sep. 21, 2015, patented, which is a continuation of U.S. application Ser. No. 12/559,601 filed Sep. 15, 2009, patented, and claims priority to U.S. Provisional Patent Application Ser. No. 61/120,209, filed Dec. 5, 2008, and the entire content of each is hereby incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to a device for the picking of stored items, and more particularly to a system for automatically picking medications, supplements, or other items to fill orders. 
     BACKGROUND 
     Hospitals, long term care and other health care facilities distribute and administer pharmaceutical products to patients in individual doses numerous times per day. Pharmaceutical products such as prescription medications, nutritional supplements and the like are often stored in bulk by pharmacies and are repackaged into containers of multiple doses based on individual prescriptions for retail or outpatient distribution. For inpatient or in-facility distribution, pharmacies also often repackage bulk pharmaceuticals into “unit of use” or “unit dose” packages, for example, multiple blister packs that are connected together in a strip that contain multiple single doses of the pharmaceutical product. 
     The traditional method for distributing individual dosage units of pharmaceutical products to patients begins with the generation of a patient order by a physician for particular medications. The patient order is delivered to the pharmacy. There, the process of interpreting the patient order, pulling the specified medication or supplements from the drug storage areas, packaging the medication or supplements, and labeling the package is routinely done manually by pharmacy support personnel. After a final check by the facility pharmacist, the packaged individual dosage units are ready for distribution. In large facilities, the packages containing the patient&#39;s order are forwarded to individual nursing units where nursing staffers distribute and administer them to the patients. 
     There are several disadvantages associated with the traditional method of distributing individual dosage units of pharmaceutical products. To begin with, the process is labor and cost intensive. Many separate labor steps are required to fill a single patient order. In large facilities servicing hundreds of patients each day, the staffing requirements to rapidly process patient orders are substantial. In addition, with so many human inputs required in the existing process, there may also be a risk of human error. 
     As an attempt to address at least some of the issues with respect to staffing requirements and human error, a variety of automated medication dispensing systems have been developed. The current landscape for automated medication dispensing is dominated by a 30-day system utilizing either “bingo cards” or unit doses supplied in a 30-day box. The known systems provide a 30-day or other multi-day supply for each patient pass-time for each prescription on a relatively long term basis. In the event the patient is discharged or the treatment is changed, the unused portion of the 30-day supply cannot be cost effectively reused even though the product may be labeled appropriately. The labor cost required to reintroduce the pharmaceutical products into the distribution system and to maintain the integrity and traceability of manufacturer and expiration data exceeds the value of the pharmaceutical products, even if the substantial restocking fees are paid by the healthcare system. As a result, such unused pharmaceutical products are returned to the pharmacy for disposal. This disposal of unused pharmaceutical products is a significant waste of those resources as well as a detriment to the environment. 
     One known pharmaceutical package dispensing system automates various aspects of the task of filling patient orders for units of use pharmaceuticals. The system employs a number of storage cartridges arranged in stacked rows on a frame. The cartridges contain strips of unit dose packages of pharmaceutical products. The packages consist of individual unit dose blisters. Each of the blisters contains a unit of use, e.g., a single tablet or capsule. Several blister packages are joined together to form the linear strips such that a given cartridge may contain several such strips stacked vertically or in roll form. Each cartridge is provided with a forward-facing opening through which a portion of the lowermost blister strip contained therein projects. A pick head is movable adjacent a respective row of cartridges to a desired location adjacent a cartridge. The pick head pulls the blister strip out of the cartridge and a cutting blade mounted on the pick head cuts an individual blister from the strip. The severed blister pack free-falls onto a conveyor or into a bin on the pick head or elsewhere and when the pick head has finished picking blisters for the order, it discharges the blisters in the bin onto a tray. The tray serves as an accumulation point servicing multiple pick heads. The tray is moved to a discharge location to dump the blisters by gravity from the tray into a funnel of a packaging station. 
     The drug dispensing machine described above and similar such systems have several disadvantages. To begin with, only one tray and discharge slide for the multiple pick heads is provided. Therefore, a pick head may have to wait for a tray to empty, which significantly reduces the picking efficiency of the pick heads and throughput of the dispensing machine. Second, the cartridge, pick head and bin design can lead to difficulties when a given blister strip is pulled, cut and dropped from the cartridge. The opening through which the blister strips project allows for significant lateral play by the strips. Further, the size of the unit doses may vary greatly and pick head retrieval and cutting mechanisms must be adjusted to accommodate unit doses of different sizes. This can lead to misalignments with the cutting blade. The gravity free-fall of the severed unit doses often results in missing or jammed unit doses producing incomplete orders and requiring manual intervention to dislodge, retrieve and/or collect the errant unit doses. 
     There is a continuing need to improve a system and overall methodology for dispensing medication orders for individual patients in health care facilities. 
     SUMMARY 
     The present invention overcomes the foregoing and other shortcomings and drawbacks of dispensing systems heretofore known for use in filling orders for medications and/or supplements. While the invention will be described in connection with certain embodiments, it will be understood that the invention is not limited to these embodiments. On the contrary, the invention includes all alternatives, modifications and equivalents as may be included within the spirit and scope of the present invention. 
     According to one aspect of the present invention, a system for assembling and dispensing an order made up of one or more individually packaged items from a plurality of different individually packaged items includes a storage module containing one or more packages of each of the items, and a conveyor having selectively assignable spaces configured to receive the packaged items associated with a particular order and to transport the packaged items to a processing location. The system further includes a pick device that is movable relative to the storage module and configured to retrieve a package from the storage module. A transfer station adjacent the conveyor receives one or more of the packaged items from the pick device and an actuator associated with the transfer station moves the packaged items from the transfer station to the conveyor when the assigned space associated with the order is in registration with the transfer station. 
     In another aspect, the system further includes a transfer nest that is movable with the pick device and which receives the packaged items from the pick device and transfers the packaged items to the transfer station. The transfer nest and/or the transfer station may have slots or channels that are shaped complimentary to the shape of the packages containing the items such that the packages are constrained for movement only along longitudinal directions of the slots or channels. Movement of the packages between the storage module and the processing location is positively controlled and the packages are not permitted to move in an unconstrained manner. 
     In another aspect, a method of filling an order that includes one or more individually packaged items selected from a plurality of different individually packaged items includes assigning a dedicated space on a conveyor for receiving one or more of the packaged items, moving the conveyor toward a processing location, picking a packaged item from a storage location, moving the item to a transfer station, and moving the item from the transfer station to the dedicated space on the conveyor when the dedicated space is in registration with the transfer station. 
     The above and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an exemplary system for storing and dispensing medications and supplements in accordance with the present disclosure. 
         FIG.  2    is a perspective view of an exemplary package for containing a single dose of a medication/supplement in accordance with the present disclosure. 
         FIG.  3    is a perspective view of an exemplary carrier of a conveyor in accordance with the present disclosure. 
         FIG.  3 A  is an end elevation view of the carrier of  FIG.  3   . 
         FIG.  4    is an enlarged perspective view of the storage module, conveyor, gantry, and pick device of  FIG.  1   . 
         FIG.  5    is an enlarged perspective view of a portion of the storage module of  FIG.  4   . 
         FIG.  6    is a partial exploded view of the storage module of  FIG.  5   . 
         FIG.  7    is an enlarged perspective view of the storage module depicted in  FIG.  6   . 
         FIG.  8    is a perspective view depicting the pick device and transfer station of the low-demand module of the dispensing system. 
         FIG.  9    is an enlarged perspective view of the pick device of  FIG.  8   . 
         FIG.  9 A  is a partial detail view along line  9 A- 9 A of  FIG.  16   . 
         FIG.  10 A  is a partial cross-sectional view depicting the pick device and transfer nest taken generally along line  10 A- 10 A of  FIG.  9   . 
         FIG.  10 B  is an enlarged cross-sectional detail view of  FIG.  10 A , illustrating a gripper and a storage tube. 
         FIG.  11    is a partial cross-sectional view, similar to  FIG.  10 A , and depicting a vacuum manifold of the pick device. 
         FIG.  12 A  is a partial cross-sectional view, similar to  FIG.  10 A , and depicting the rotating cam in a second position wherein a gripper is extended to engage a package. 
         FIG.  12 B  is an enlarged detail view of the gripper and storage tube of  FIG.  12 A . 
         FIG.  12 C  is a partial cross-sectional view, similar to  FIG.  12 A , and depicting the vacuum manifold. 
         FIG.  12 D  is a partial cross-sectional view, similar to  FIG.  12 A , and depicting an indexing mechanism of the pick device. 
         FIG.  13 A  is a partial cross-sectional view, similar to  FIG.  12 D , wherein the grippers have been indexed to the next position. 
         FIG.  13 B  is a partial cross-sectional view, similar to  FIG.  13 A , wherein the grippers have been retracted by the cam. 
         FIG.  13 C  is a partial cross-sectional top view, similar to  FIG.  13 B , illustrating the vacuum applied to the grippers. 
         FIG.  14 A  is a partial cross-sectional view, similar to  FIG.  13 B , wherein the grippers are indexed to a successive position. 
         FIG.  14 B  is a partial cross-sectional view, similar to  FIG.  14 A , depicting the grippers extended and retracted by the cam. 
         FIG.  14 C  is a partial cross-sectional view, similar to  FIG.  14 B , illustrating the vacuum pressure applied to the grippers. 
         FIG.  15    is a partial cross-sectional view, similar to  FIG.  14 B , depicting the grippers of the pick device indexed to the next position. 
         FIG.  16    is a partial cross-sectional view depicting the transfer of packages from the transfer nest to the transfer station. 
         FIG.  17    is a partial cross-sectional view, similar to  FIG.  16   , depicting the packages in the queue support of the transfer station. 
         FIG.  18    is a partial cross-sectional view, similar to  FIG.  17   , depicting the packages transferred between the queue support and a carrier on the conveyor. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    depicts an exemplary automated dispensing system  10  in accordance with the principles of the present disclosure. In the embodiment shown, the dispensing system  10  is configured to store and dispense individually packaged and labeled doses of medications/supplements, and to assemble the dispensed medications/supplements into individual medication orders, such as time-pass medication orders to be delivered to a long-term care facility, for example. It will be appreciated, however, that a dispensing system in accordance with the present disclosure may alternatively be configured to dispense other items. The dispensing system  10  is divided into distinct modules that are dedicated to dispensing the medications/supplements based on the demand, or order frequency, of those items. In the embodiment shown, a first module  12  is configured to dispense medications/supplements having a relatively high demand or order frequency, and a second module  14  of the dispensing system  10  is configured to store and dispense medications/supplements having a relatively lower demand or order frequency. 
     In the embodiment shown and described herein, the medications/supplements are provided in packages  16  sized to receive an individual dose of a particular medication/supplement, commonly referred to as a blister pack. With reference to  FIG.  2   , an exemplary package  16  comprises a base portion  18  defining a cavity for receiving the individual dose of the medication/supplement  20 , and a generally planar closure  22  disposed over an open end of the base portion  18 . The packages  16  may be provided with information  24  related to the medication/supplement  20  contained in the packages  16 , such as the name of the medication/supplement  20 , the manufacturer, the date manufactured, the lot number, and/or other information. In the embodiment shown, information  24  is provided on the closure  22  and includes machine-readable information, such as a bar-code, that may be used to facilitate the automated storing, tracking, dispensing, and packaging of orders. 
     With continued reference to  FIG.  1   , the dispensing system  10  further includes an endless conveyor  30  comprising a plurality of carriers  32  that move past the first, high-demand module  12  and the second, low-demand module  14  to collect ordered medications/supplements and carry them to a designated location for further processing. In the embodiment shown, a first end  34  of the conveyor  30  is positioned adjacent the high-demand module  12 . The carriers  32  are moved along the conveyor  30  past the high-demand module  12  and the low-demand module  14  toward a second end  36  where the medications/supplements are packaged for delivery to a long term care facility. In the embodiment shown in  FIG.  1   , the conveyor  30  comprises a pair of oppositely disposed, longitudinally extending rails  38   a ,  38   b  supporting the plurality of carriers  32 . The conveyor  30  may further comprise cross-members  40  extending between the rails  38   a ,  38   b  and support legs  42  configured to support the longitudinally extending rails  38   a ,  38   b  a distance above a floor surface. 
       FIGS.  3  and  3 A  depict an exemplary carrier  32  comprising an elongate, generally rectangular body  50  having a longitudinal channel  52  formed into one side and extending between the ends of the body  50 . The channel  52  is shaped complementarily to the shape of the packages  16  and includes a deep central portion  54  and shallower side portions  56   a ,  56   b  disposed on opposite sides of the central portion  54 , whereby a package  16  can be received in the channel  52  with the base  18  positioned in the central portion  54  and the sides of the closure  22  supported on the side portions  56   a ,  56   b . The side portions  56   a ,  56   b  are enclosed at their upper ends, such as by top plates  58  or other structure so that packages  16  received in the channel  52  are constrained for movement only along a longitudinal direction of the channel  52 . The focus of this disclosure is the low-demand module  14  of the dispensing system, depicted in more detail in  FIG.  4    and discussed below. 
     Referring now to  FIG.  4   , the low-demand module  14  comprises a storage module  60  for storing the individually packaged and labeled medications/supplements, a pick device  62  for retrieving selected medications/supplements from the storage module  60 , and a transfer station  64  for delivering the selected medications/supplements to the carriers  32  of the conveyor  30  to fill orders. The storage module  60  comprises one or more storage units  66  positioned alongside the conveyor  30 , as may be desired, to accommodate storage of the medications/supplements needed to fill the medical orders. With continued reference to  FIG.  4   , and referring further to  FIGS.  5 - 7   , each storage unit  66  comprises a plurality of generally rectangular, vertically-spaced plates  68  and a plurality of laterally spaced walls  70  disposed between each plate  68  to define an array of elongate bins  72  configured to receive storage tubes  74  containing stacked packages  16  of the individually packaged medications/supplements. The storage tubes  74  are slidably received in the respective bins  72  at first, receiving ends  76  of the bins  74 . 
     In the embodiment shown, the plates  68  and walls  70  of the storage unit  66  are formed from aluminum sheet material. The walls  70  are formed with notches  78  and tabs  80 , and the plates  68  are formed with corresponding slots (not shown) whereby the walls  70  and plates  68  may be assembled together to form the array of bins  72 . In the embodiment shown, the bins  72  have a generally rectangular cross-sectional shape, as do the storage tubes  74  that are received within the respective bins  72 . In this embodiment, the tubes  74  are formed from extruded plastic material and an end cap  82  disposed at one end of the tube  74  facilitates dispensing the packages  16  therefrom. As shown in  FIG.  7   , the end cap  82  includes a slot  84  along an upwardly facing side of the storage tube  74  whereby an individual package  16  may be moved in a direction transverse to the longitudinal axis of the storage tube  74  for removal of the package  16  from the storage tube  74  through the slot  84 . With continued reference to  FIG.  7   , each bin  72  is provided with a registration pin  90  proximate a second, dispensing end  92  that faces the pick device  62 . As the storage tubes  74  are placed within the respective bins  72 , the registration pins  90  engage another slot  94  formed on the end cap  82  to position the end cap  82  at a location that facilitates engagement and retrieval of the individual packages  16  stored in the tube  74  by the pick device  62 , as will be described in more detail below. 
     As depicted in  FIG.  5   , each storage unit  66  is supported on a base  100  so that storage tubes  74  supported in the bins  72  of the storage unit  66  may be positioned for proper access by the pick device  62 . The base  100  comprises a generally flat plate  102  that may be bolted or otherwise secured to the floor surface. The array of bins  72  may be pivotally coupled to the plate  102  by appropriate pin connections  104 ,  106 , and may be adjusted to have a desired inclination angle relative to the floor surface by an adjustable link  108  coupled between the array of bins  72  and the plate  102 . The inclined orientation of the bins  72  of the storage unit  66  places the dispensing ends  92  of the bins  72  at a lower elevation than the receiving ends  76 . 
     The packages  16  of medications/supplements are stacked one atop another within the storage tubes  74 , and the storage tubes  74  are slidably received within the respective bins  72  of the storage unit  66 . The storage tubes  74  are inserted with the end caps  82  positioned at the dispensing ends  92  of the bins  72  such that the stacked packages  16  within the tubes  74  are urged by gravity in a direction toward the end caps  82  at the dispensing ends  92  of the bins  72 . A weight (not shown) may be provided on top of the uppermost package  16  within each storage tube  74  to facilitate movement of the packages  16  toward the end caps  82 . As depicted in  FIG.  10 B , each bin  72  may be provided with a sensor  97  proximate the dispensing end  92  for detecting the presence of packages  16  within the storage tube  74  supported in the bin  72 , and for communicating with a control  240  to indicate when the storage tube  74  needs to be replaced with a storage tube  74  filled with packages  16 . The bins  72  may also be provided with one or more sensors  99  for detecting the presence of a storage tube  74  in the bin, and for communicating with the control  240  when a storage tube  74  is not in the bin  72 . In the embodiment shown, in  FIGS.  10 B and  12 B , sensors  97  for detecting the pressure of packages  16  in a storage tube  74  are located with the registration pin  90 . 
     Each storage tube  74  contains only a single type of medication/supplement, and the storage tubes  74  may be provided with information  96  identifying the particular type of medication/supplement contained within the packages  16  stacked within the tube  74  ( FIG.  7   ). In one embodiment, the information provided on the storage tubes  74  includes machine readable information, such as bar codes, RFID, or other types of machine readable information, to facilitate the automated storage, tracking and dispensing of the medications/supplements. 
     The medications/supplements stored in the array of bins  72  of the storage units  66  of the storage module  60  are retrieved by the pick device  62  and are delivered to a transfer station  64  for subsequent transfer to a designated carrier  32  as the carrier  32  moves past the transfer station  64  on the conveyor  30 , as will be described in more detail below. With reference to  FIGS.  4  and  8   , the pick device  62  comprises a pick head  110  and a transfer nest  112  supported on a transfer frame  114  that moves with the pick head  110 . The pick device  62  is supported on a vertically inclined gantry  116  having vertical frame members  118  and horizontal frame members  120  positioned proximate the dispensing ends  92  of the bins  72  of the storage module  60  for access to the storage tubes  74 . A gantry crossmember  122  is driven by a first motor  124  for movement longitudinally along the horizontal frame members  120 , and a second drive motor  126  moves the pick device  62  vertically along the gantry crossmember  122  so that the pick head  110  can access any of the plurality of storage tubes  74  housed in the storage module  60 . Flexible cable guides  128   a ,  128   b  may be provided adjacent the gantry crossmember  122  and/or the horizontal frame members  120  to house cables or wires extending between the pick device  62  and corresponding power supplies and/or control modules. 
     As shown in  FIGS.  9  and  10 A , the pick head  110  comprises a plurality of grippers  130  extending from a rotatable housing  132  for engaging and retrieving selected packages  16  from the storage tubes  74  supported in the storage module  60 . Four grippers  130   a ,  130   b ,  130   c ,  130   d  are depicted and are collectively referred to as “grippers  130 ” herein. The transfer nest  112  is supported within a transfer frame  114  coupled to the pick head  110  for movement therewith, such that packages  16  selected by the pick head  110  may be received onto the transfer nest  112  and subsequently delivered to the transfer station  64 . In the embodiment shown, the transfer nest  112  includes four slots  134  for receiving the packages  16  of medications/supplements from the grippers  130  of the pick head  110 . It will be appreciated, however, that the transfer nest  112  may alternatively have a fewer number or a greater number of slots  134 , as may be desired. The slots  134  of the transfer nest  112  are configured to receive the packages  16  from the grippers  130  of the pick head  110  and to maintain positive control over the motion of the packages  16  as they are moved to the transfer station  64 . To this end, the slots  134  are shaped complementarily to the shape of the packages  16 , in a manner similar to the channels  52  of carriers  32  and as depicted in  FIG.  9 A . 
     The transfer nest  112  is movable along a shaft  140  in a longitudinal direction relative to the pick head  110  so that the selected packages  16  of medications/supplements may be received in one of the plurality of slots  134  on the transfer nest  112  by aligning a selected slot  134  in registration to receive a package  16  from the grippers  130  of the pick head  110 . The transfer nest  112  is also pivotable about a shaft  142  coupled to the transfer frame  114  to position the transfer nest  112  adjacent the transfer station  64  for delivery of the selected packages  16  of medications/supplements to the transfer station  64 . In the embodiment shown, the transfer nest  112  is pivotally coupled to the transfer frame  114  by a shaft  142  received in shaft supports  144  extending from the transfer frame  114 . A bracket  146  extending from the transfer nest  112  is coupled at a pivot joint  148  to the end of a drive rod  150  of a pneumatic piston  152 , whereby the transfer nest  112  can be pivoted around the shaft  142  by actuation of the pneumatic piston  152 , from a first position wherein the transfer nest  112  is located adjacent the pick head  110  for receiving the selected packages  16  of medications/supplements (depicted in  FIGS.  8  and  9   ), to a second position wherein the transfer nest  112  is positioned adjacent the transfer station  64  (depicted in  FIG.  16   ). 
     Referring again to  FIG.  8   , the transfer station  64  comprises a slide assembly  160  for moving the packages  16  of medications/supplements from the transfer nest  112 , and a queue support  162  for receiving the packages  16  of medications/supplements from the transfer nest  112  and supporting them until the carrier  32  assigned to receive the packages  16  of medications/supplements for a particular order is positioned at the queue support  162  in registration for receiving the packages  16 . The slide assembly  160  comprises a plurality of individually actuatable slide members  164  having upwardly extendable prongs  166  that engage the packages  16  of medications/supplements supported on the transfer nest  112  when the transfer nest  112  has pivoted to the second position. The prongs  166  slide the packages  16  of medications/supplements from the transfer nest  112  into corresponding channels  168  formed in the queue support  162  of the transfer station  64 . In the embodiment shown, the channels  168  formed in the queue support  162  are shaped complementarily to the shape of the packages  16  of medications/supplements, in a manner similar to the channels  52  of carriers  32 , such that the packages  16  received in the respective channels  168  of the queue support  162  are constrained and allow for movement only along longitudinal directions of the channels  168 . 
     With continued reference to  FIG.  9   , and referring further to  FIG.  10 A , operation of the pick device  62  to retrieve selected packages  16  of medications/supplements from the storage tubes  74  supported in the array of bins  72  of the storage units  66  and to place the selected packages  16  in the transfer nest  112  for subsequent transfer to the transfer station  64  will now be described. The pick device  62  comprises a pick head  110  having four grippers  130  disposed generally circumferentially around a housing  132  of the pick head  110  and arranged such that pairs of grippers  130   a ,  130   c  and  130   b ,  130   d  are positioned on diametrically opposite sides of the housing  132 . Each gripper  130  comprises a gripper arm  170  slidably received in guides  172  coupled to the housing  132  to facilitate movement of the gripper arms  170  along radial directions relative to the housing  132 . Springs  174  coupled to the gripper arms  170  and contacting the guides  172  bias the gripper arms  170  in directions radially outwardly from the housing  132 . The housing  132  of the pick head  110  is rotatable to index the grippers  130  from positions adjacent the storage tubes  74 , for engaging and retrieving packages  16  of medications/supplements, to positions adjacent the transfer nest  112  for placing the selected packages  16  into one or more slots  134  of the transfer nest  112 . As depicted in  FIG.  12 D , the pick head  110  of the embodiment shown is rotatably indexed by a Geneva drive mechanism  180  for successive, intermittent positioning of the respective grippers  130  adjacent the storage module  60  and the transfer nest  112 . A driven wheel  182  is rotatably supported on a central shaft  184  of the pick head  110  and is driven for intermittent rotation by a drive wheel  186  supported on a rotating drive shaft  188  spaced from the central shaft  184 . As the drive wheel  186  rotates, engagement rods  190  positioned on diametrically opposed sides of the drive wheel  186  engage corresponding slots  192  formed in the driven wheel  182  to rotate the driven wheel  182 . The driven wheel  182  is coupled to an index plate  194 , which is in turn coupled to the pick head housing  132 , whereby intermittent rotational motion is imparted to the housing  132  to move the grippers  130 . 
     The pick head  110  is also configured to move the gripper arms  170  along directions extending radially from the housing  132  to facilitate engaging the packages  16  of medications/supplements stored in the storage tubes  74  and placing the selected packages  16  within slots  134  on the transfer nest  112 . Radial movement of the gripper arms  170  is controlled by a rotating cam plate  200  disposed within the pick head housing  132 . An aperture  202  formed in the cam plate  200  defines a cam surface  204  that engages follower pins  206  coupled to the proximal ends  208  of the gripper arms  170 . In the embodiment shown, the cam surface  204  is configured to move one pair of diametrically opposed gripper arms  170  radially outwardly (associated with grippers  130   b  and  130   d , for example) while the other oppositely disposed pair of gripper arms  170  is moved radially inwardly (associated with grippers  130   a  and  130   c , for example). The inward/outward motion of the gripper arm pairs is alternated as the cam plate  200  rotates within the pick head housing  132 . 
     The distal end  210  of each gripper arm  170  includes a suction cup  212  for applying vacuum pressure to the planar closure  22  of a package  16  positioned adjacent the dispensing slot  84  of a storage tube  74 . The distal end  210  of each gripper arm  170  may include a pin  214  for positively engaging an edge of the closure  22  of the package  16  to facilitate lifting the package  16  from the dispensing slot  84  of the storage tube  74 . However, the pin  214  may be eliminated to avoid possible damage to the packages  16  during transfer to the slots  134 . Vacuum pressure is supplied to the suction cups  212  by conduits  220  that are operatively coupled to a vacuum manifold  222  disposed within the pick head housing  132  and to a vacuum passage  223  in the gripper arm  170 . As shown in more detail in  FIG.  11   , the vacuum manifold  222  comprises a vacuum passage  224  configured to provide vacuum pressure to the suction cups  212  of the respective grippers  130  at appropriate positions of the grippers  130  relative to the pick head housing  134  to facilitate retaining the packages  16  on the distal ends  210  of the gripper arms  170  from the time that the packages  16  are retrieved from the storage tubes  74  until the packages  16  are placed in the slots  134  of the transfer nest  112 . To this end, the vacuum passage  224  comprises a first portion  224   a  that extends generally circumferentially around a portion of the pick head housing  132 , and a second portion  224   b  extending in a radial direction along the manifold  222  and communicating with an outlet port  226  coupled to a source of vacuum pressure. 
     With continued reference to  FIGS.  10 A and  10 B , the retrieval of a selected package  16  from a storage tube  74  by the pick head  110  will now be described. In  FIG.  10 A , the pick head  110  has been moved to a location relative to the storage module  60  to position a first gripper  130   a  adjacent a storage tube  74  supported in the storage module  60  and containing a plurality of packages  16  of a particular medication/supplement required to fill an order. The distal end  210  of the first gripper arm  170  is spaced from the end cap  82  of the storage tube  74 . With the first gripper  130   a  positioned adjacent the storage tube  74 , vacuum pressure is supplied to the suction cup  212  by the vacuum manifold  222 . The cam plate  200  rotates to move the first gripper arm  170  in a direction toward the end cap  82  of the storage tube  74  such that the suction cup  212  engages the surface of the closure  22  of the lower-most package  16  in the storage tube  74 , and the pin  214  engages the side edge of the package  16 , as depicted in  FIGS.  12 A and  12 B . The vacuum pressure applied at the suction cup  212  draws the package  16  firmly against the distal end  210  of the first gripper  130   a , and lifts the package  16  through the dispensing slot  84  of the end cap  82  as the Geneva drive mechanism  180  is indexed to the next position, as depicted in  FIGS.  12 D and  13 A . 
     Referring now to  FIG.  13 A , the selected package  16  is supported on the distal end  210  of the first gripper  130   a  adjacent a sensor  230  configured to detect the presence of a package  16  on the first gripper  130   a . The sensor  230  may also be configured to read machine readable information provided on the package  16 . The sensor  230  can therefore be used to confirm that a package  16  was retrieved by the first gripper  130   a  and that the selected package  16  is the package  16  intended to be selected to fill the order. Indexing of the Geneva drive mechanism  180  to move the first gripper  130   a  and the package  16  supported thereon adjacent the sensor  230  also moves the second gripper  130   b  into a position for engaging and retrieving another package  16  from the storage tube  74 , in the event that more than one dose of the medication/supplement is required to fill the order. If a different medication/supplement is required, the pick device  62  may be moved on the gantry  116  to position the second gripper  130   b  adjacent an appropriate storage tube  74  containing packages  16  of the desired medication/supplement. 
     The cam plate  200  then rotates to move the first gripper  130   a  supporting the package  16  in a direction radially inwardly toward the pick head housing  132 , while at the same time the second gripper  130   b  is moved radially outwardly to engage a subsequent package  16  supported in a respective storage tube  74  for retrieval of the package  16  as described above.  FIG.  13 C  depicts the vacuum manifold  222  and illustrates how vacuum pressure is maintained at the suction cup  212  of the first gripper  130   a  adjacent the sensors  230 . 
     Referring now to  FIG.  14 A , the Geneva drive mechanism  180  indexes the first gripper  130   a  to a position adjacent the transfer nest  112 , while simultaneously moving the second gripper  130   b  (now supporting a package  16 ) adjacent the sensor  230 , and moving the third gripper  130   c  adjacent the storage module  60  to a position to retrieve a subsequent package  16  from the same storage tube  74 , or from a different storage tube  74 , as may be required. As the drive wheel  186  of the Geneva drive mechanism  180  continues to rotate, the cam plate  200  rotates to move the first gripper  130   a  radially outwardly to position the package  16  in registration with a selected slot  134  of the transfer nest  112 , as depicted in  FIG.  14 B . Simultaneously, the second gripper  130   b  is moved in a direction radially inwardly, while the third gripper  130   c  is moved radially outwardly to engage a subsequent package  16 .  FIG.  14 C  illustrates the vacuum manifold  222  with the first gripper  130   a  adjacent the transfer nest  112  and shows how vacuum pressure is applied to the suction cup  212  at this position. As the first gripper  130   a  is subsequently indexed to the next position, vacuum pressure applied through the first portion  224   a  of the vacuum passage  224  is shut off to the conduit  220 , and the package  16  is released into the slot  134  on the transfer nest  112 , as illustrated in  FIG.  15   , which depicts the pick head  110  indexed to the next successive position by the Geneva drive mechanism  180 , whereby the second gripper  130   b  is in position to place a package  16  supported on the second gripper  130   b  onto the transfer nest  112 . After the last package  16  in an order is picked, the Gantry  116  moves the pick device  62  to a location between the storage units  66 , where there are no storage tubes  74 . Since there are no packages  16  present, the pick device  62  can advance two positions thereby transferring the packages already supported by the remaining two grippers  130  into the slot  134  of the transfer nest  112  without acquiring additional packages  16 , completing the order. 
     After the packages  16  of medications/supplements associated with one or more orders are placed on the transfer nest  112 , the pick device  62  is moved by the gantry  116  to a position adjacent the transfer station  64 . The pneumatic cylinder  152  is then actuated to pivot the transfer nest  112  from the first position adjacent the pick head  110  to the second position adjacent the slide assembly  160  of the transfer station  64 , as depicted in  FIG.  16   . With the transfer nest  112  in the second position, one or more of the slide members  164  may be actuated to push the selected packages  16  from the slots  134  on the transfer nest  112  into corresponding channels  168  on the queue support  162  in registration with the slots  134  of the transfer nest  112 , as depicted in  FIG.  17   . The packages  16  of medications/supplements supported in the queue support  162  are held until the designated carrier  32  assigned to receive the particular order associated with the medications/supplements is in position adjacent the corresponding channel  168  of the queue support  162 . Thereafter, the prongs  166  of the slide member  164  are further actuated to push the corresponding packages  16  of medications/supplements from the queue support  162  into the appropriate carrier  32  on the conveyor  30 , as depicted in  FIG.  18   . 
     After the packages  16  of medications/supplements have been moved from the transfer nest  112  to the slide assembly  160 , the transfer nest  112  is pivoted from the second position back to the first position, adjacent the pick head  110 , and the pick device  62  is moved on the gantry  116  to a position adjacent a selected storage tube  74  for retrieval of a package  16  required for the next order. The process described above is repeated to assemble additional orders. After the packages  16  of medications/supplements for an order have been transferred from the queue support  162  to the assigned carrier or carriers  32 , the slide members  164  return to retracted positions as depicted in  FIG.  16    to await the delivery of the next batch of packages  16  from the pick device  62 . Having received all of the packages  16  of medications/supplements required to fill the orders, the carriers  32  continue along the conveyor  30  to a packaging station for subsequent processing into appropriate containers for delivery to the one or more long-term care facilities. 
     In the embodiment shown, the low-demand module  14  of the dispensing system  10  includes five individual transfer stations  64  configured to receive packages  16  of medications/supplements for transfer to respectively assigned carriers  32  on the conveyor  30 , as described above. it will be appreciated, however, that the dispensing system may alternatively include fewer than five transfer stations  64 , or greater than five transfer stations  64 , as may be desired for the particular requirements of the dispensing system  10 . The provision of multiple transfer stations  64  enables the pick head  110  to preselect the packages  16  of medications/supplements associated with a plurality of orders and transfer the packages  16  into respective queue supports  162  to accommodate substantially continuous operation of the conveyor  30 . In one embodiment, the conveyor  30  is configured to incrementally move the carriers  32  from the first end  34  to the second end  36  such that a carrier  32  is indexed approximately every 3 seconds. 
     The dispensing system  10  further includes a control  240  configured to receive orders for medications/supplements and to process the orders for delivery to a long-term care facility. Orders may be electronically received by the control  240  from one or more long-term care facilities, such as by transmission over a network, or by any other suitable method. Alternatively, orders can be input directly into the control  240  via an appropriate interface, such as a keyboard or other suitable devices. The control  240  identifies which medications/supplements are required from the high-demand module  12  and the low-demand module  14  to fill each order. In one embodiment, the orders corresponding to each medication pass to be administered to a particular patient for that particular day are processed by the control  240  such that the packages  16  of medications/supplements for each medication pass to be administered to the patient are assembled into a package, and the packages of medication passes are then grouped together for delivery to the long-term care facility. 
     The control  240  assigns one or more carriers  32  to receive the packages  16  of medications/supplements for each order. The control  240  then controls the movement of the carriers  32  on conveyor  30  through the high-demand module  12  and the low-demand module  14  to receive the packages  16  as described above and in related U.S. patent application Ser. No. 12/559,630, filed on even date herewith and incorporated herein in its entirety. The control  240  controls operation of the low-demand module  14  to retrieve the packages  16  of medications/supplements for the orders ahead of the arrival of the carriers  32  assigned to the orders and while the carriers  32  are receiving the ordered medications/supplements from the high-demand module  12  as the carriers  32  are moved past the high-demand module  12 . The transfer nests  64  provide a buffer to accumulate the medications/supplements in advance of the arrival of the carrier  32  for the specific order. The control  240  is coupled to an order entry database and via a web service the orders are passed to the dispenser  10  one at a time. Alternatively, multiple orders may be passed at a time, for example, ten orders passed at a time. As such, the remaining, subsequent orders are buffered in the database. 
     In another embodiment, the dispensing system  10  may be configured to receive and process short turn-around time orders (“stat orders”) that are received separately from the periodically received orders from the long-term care facilities. The control  240  integrates the stat orders into the orders being processed and may direct the assembled stat order to a separate location for subsequent handling. 
     The control  240  may also be configured to receive signals from various sensors associated with the dispensing system  10  to facilitate managing operation of the dispensing system  10 . For example, in one embodiment, the control  240  is configured to receive signals from sensors  97 ,  99 ,  230  of the low-demand module  14  related to the detection of packages  16  in a storage tube  74 , the presence of storage tubes  74  in a bin  72 , and the presence of a package  16  supported on a gripper  130 , respectively. When the control  240  receives a signal from a sensor  97  indicating that the storage tube  74  associated with the sensor  97  is empty, control  240  provides a signal to an operator indicating that the storage tube needs to be replaced or replenished. When control  240  receives a signal from a sensor  99  indicating that a storage tube  74  is not detected in the associated bin  72 , the control may provide a signal to an operator indicating the detected absence of a storage tube  74 . Inventory status is maintained in the control  240  and the sensor  230  provides a fail-safe check in case the inventory is not correct in that the control  240  will not direct the pick device  62  to pick from an empty location. When control  240  receives a signal from a sensor  230  indicating that a package  16  was not detected on a gripper  130 , the control may provide a signal to an operator that the package  16  was not detected. The control  240  may also flag the order associated with the detected absence of the package  16  for separate processing to confirm that the order is faulty and, optionally, to correct the error in filling the order. The control  240  may also be configured to stop operation of the dispensing system  10  when a detected error will adversely affect operation of the dispensing system  10  to fill orders. 
     The control  240  may also be configured to optimize the picking of packages  16  from the storage module  60  and the transfer of the packages  16  to the carriers  32 . In particular, the control  240  may be configured to monitor the order frequency of the medications/supplements and to assign locations for the storage tubes  74  in the bins  72  of the storage module  60  based on order frequency. For example, the control  240  may assign locations for storage tubes  74  containing medications/supplements that have a relatively higher order frequency to be placed in bins  72  that are located relatively lower in the storage units  66  and/or are positioned relatively closer to the transfer stations  64  so that the distance required to be traversed by the pick device  62  to retrieve packages  16  of high demand medications/supplements is minimized, thereby decreasing the time required to transfer packages  16  for the orders in the queue supports  162 . Accordingly, the particular locations of the storage tubes  74  within the bins  72  of the storage module  60  can be dynamic and may be modified by the control  240 , as may be desired for efficient processing of orders. 
     In another embodiment, the control  240  may be configured to track the dispensing of medications/supplements from the storage tubes  74  within the storage module and to provide signals to an operator when the supply of packages  16  in a given storage tube  74  is becoming low. This allows replacement of the storage tubes  74  or, alternatively, replenishment of the packages  16  within the storage tubes  74 , at convenient times. The dispensing system  10  is also configured to facilitate replacement of the storage tubes  74  or, alternatively, replenishment of the packages  16  within the storage tubes  74 , on-the-fly while the dispensing system  10  is operating to fill orders. In particular, the configuration of the storage module  60  facilitates access to the receiving ends  76  of the bins  72  for removal and replacement of storage tubes  74  while the dispensing system is operating to fill orders. In the event that the pick device  62  attempts to retrieve a package  16  from a storage tube  74  when the storage tube  74  has been removed for replacement, the control  240  receives a signal from sensor  99  associated with the bin  72  and may control the pick device  62  to wait until the storage tube  74  has been replaced before attempting to retrieve the package  16 . 
     While  FIG.  1    illustrates the dispensing system  10  as having a high-demand module  12  and a low demand module  14  provided on only one side of the conveyor  30 , the dispensing system  10  may alternatively be configured with high-demand modules  12  and low-demand modules  14  provided on both sides of the conveyor  30 , to accommodate the quantity of medications/supplements and throughput requirements of the system, as may be desired. In such a configuration, the high-demand modules  12  and low demand modules  14  on both sides of the conveyor  30  are controlled by a common controller  240  and operate generally as described above and in U.S. patent application Ser. No. 12/559,630, however, the packages  16  of medications/supplements may be transferred to the carriers  32  moving along the conveyor  32  from the high-demand modules  12  and low-demand modules  14  on both sides of the conveyor  30 . 
     While the present invention has been illustrated by the description of one or more embodiments thereof, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features described herein may be utilized alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.