Abstract:
The invention provides an improved robotic handler for multi-well plates. The handler comprises a vertical elevator with integral mounts for instruments used in cellular experiments. This solution reduces overall mechanical complexity while reducing the working volume of previous collections of devices with similar function.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of provisional patent application Ser. No. 61/797,413, filed Dec. 6, 2012. 
     
    
     FEDERALLY SPONSORED RESEARCH 
       [0002]    Not applicable 
       SEQUENCE LISTING OR PROGRAM 
       [0003]    Not applicable 
       FIELD OF THE INVENTION 
       [0004]    This invention relates to a vertical storage rack with an integrated material handler. The system provides multiple mounting locations for instruments including instruments used for cellular measurements and a robotic elevator for supplying the instruments with suitable materials for measurement. 
       BACKGROUND OF THE INVENTION 
       [0005]    A robot, designed as an automated material handler, is an effective way of increasing the efficiency and throughput of an industrial process. In particular, robots have been very useful in cellular biology by taking over much of the material handling requirements for large scale experiments. In many cases, these experiments are further enabled by using microtiter plates in which many different experiments can be performed in a standard form factor. 
         [0006]    The prior art documents many examples of robots capable of handling microtiter plates and being mechanically integrated near instruments so as to move the plates to and from different process steps or instruments. To date, automated, plate handling systems have provided arrangements that attempt to integrate a general purpose robot with conventional instruments. Thus, it is common to see a multi-degree-of-freedom robotic arm in the midst of and serving plates to many different stations arrayed around itself. Some common arrangements will also lay out stations in a linear fashion along a laboratory bench. All these solutions have required a large working volume. In other words, the volume used by the robot to move plates plus the volume occupied by the array of instruments is large. 
         [0007]    However, laboratory space is expensive and moving plates large distances is cumbersome and requires safety considerations. Methods to reduce the working volume and complexity of systems are important. High-throughput cell research needs a compact, scalable format for handling microtiter plates among multiple plate-based instruments. 
         [0008]    The present invention provides a novel solution that uniquely combines automated plate handling and instrument mounting. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is a robotic system for transporting microtiter plates. The system is configured with a support structure that has mounting locations for multiple instruments used in conjunction with microtiter plates. 
         [0010]    The robotic plate transporting system is comprised of several sub-assemblies including a support structure adjacent to a plate elevator. The system components are vertically integrated to conserve lab and bench space. This orientation is a convenient layout for the linear elevator subassembly. The support structure provides the mechanical stability for the plate elevator which is attached to the support at several locations. 
         [0011]    The construction of the support structure can be accomplished with a variety of mechanical assemblies. The preferred embodiment includes four vertical struts of extruded aluminum with connective cross-members and sheet components to tie the struts together mechanically forming a stable frame/rack with shelf positions. 
         [0012]    The elevator subassembly includes a plate gripper for grabbing and releasing plates and a gripper mount that can move vertically with a carriage along a linear rail. A motor driven belt pulls the carriage along the rail under command from control electronics. 
         [0013]    The present invention is constructed and arranged to simplify the task of automating cellular experiments and more particularly to simplify the task of manipulating large numbers of microtiter plates among instrumentation. The robotic system is extremely compact and moves microtiter plates along a well defined trajectory. It combines the tasks of instrument storage and plate handling typically carried out by separate and distinct structures. As a result, it is more space efficient than previous general purpose robotic solutions. 
         [0014]    Further objects and advantages will become apparent from the detailed descriptions that follow. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  shows an illustration of several instruments mounted in a robotic rack assembly with support struts. 
           [0016]      FIG. 2  shows a preferred embodiment of a rack and robotic strut assembly 
           [0017]      FIG. 3  shows detail of a instrument shelf with vibration damping 
           [0018]      FIG. 4  shows an illustration of a stack of instruments with locating features, an integrated elevator, and vibration damping means. 
           [0019]      FIG. 5  shows a robotic rack assembly with safety shield. 
           [0020]      FIG. 6  shows a robotic strut assembly 
           [0021]      FIG. 7  shows an exploded view of a robotic strut assembly 
           [0022]      FIG. 8  shows a preferred gripper assembly 
           [0023]      FIG. 9  shows a preferred gripper mount assembly 
           [0024]      FIG. 10  shows a side view of a robotic strut assembly 
           [0025]      FIG. 11  shows an enlarged side view of a robotic strut assembly 
           [0026]      FIG. 12  shows a side view including details for a vertical drive mechanism 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    A preferred embodiment of the present invention is illustrated in  FIG. 1  with mounted instruments. In this view, instruments, for example  21 , are mounted in a rack. The rack structure includes four struts, two of which are visible  11  and  24 . Strut  11  is a robotic strut providing both structural support for the rack and serving as a plate elevator. The robotic strut assembly includes a gripper  13  for grasping microtiter plates and a gripper mount  12  which supports the gripper and is mounted to movable components of strut  11 . In this case, the movable components move vertically  along a linear rail. 
         [0028]    Each mounted instrument is supported by two shelves; an example is shown as  15 . Each instrument is further characterized by having a port  23 , aligned with the vertical path  22  of the gripper, and positioned to receive microtiter plates. The vertical alignment reduces the required working volume of the robotic strut. 
         [0029]    An alternative embodiment uses a plate elevator that is not disposed to move vertically along a linear rail but instead grips a plate and moves it among instruments in the vertical rack along a path that is not linear. 
       Instrument Rack Assembly  
       [0030]    The preferred embodiment  10  is shown in  FIG. 2 . Robotic rack portion or strut  11  and three additional non-robotic struts including  24  are mechanically bound together with a top plate  18 , a bottom plate  19 , and a back plate  16  using threaded fasteners, welding, or a combination of both. Robotic strut  11  is configured with a gripper mount  12  and gripper  13 . The gripper mount is arranged to move vertically on a carriage and linear rail (not visible) which is mounted on the inside length of U-channel  33 , visible in  FIG. 6 . The U-channel is fixed to an additional vertical support  11   a  constructed from an extruded aluminum profile. The gripper mount, in turn, provides a means for horizontal linear motion for gripper  13 . Instrument mounting shelves, including  15 , span rack struts from front to back providing mounting locations and additional structural rigidity to the rack assembly. A fixed platform  14  provides a holding tray for microtiter plates and is used as a hand-off location when interacting with additional robotic plate handlers. For clarity,  FIG. 3  shows the preferred embodiment of a mounting shelf  15 . The shelf includes a fixed portion  102  which rigidly connects front and back struts. A floating portion  105  is isolated from  102  and external vibration sources by compliant locating structures  101  (e.g. urethane dampers). An instrument (not shown) can be mounted on the shelf lip  103  of floating portion  105  and further located and fastened in place using mounting holes  104 . 
         [0031]    An alternative configuration of instruments is shown in  FIG. 4 . In this embodiment, instruments, such as  21 ′, are stacked vertically and both supported and constrained in location by features integral to each instrument. For example, raised feature  25 ′ is received and interlocked with receptacle feature  24 ′. Thus, each instrument and its corresponding receiving port  23 ′ are positioned accurately for subsequent interaction with a robotic elevator assembly including a base structure  19 ′, vertical riser  11 ′, gripper mount  12 ′, and gripper  13 ′. Interstitial mounting features  15 ′ provide vibration damping between instruments. 
         [0032]    Thus, the present invention provides the functionality of a number of instruments as well as automated material handling for those instruments in only a bit more bench or floor space than a single instrument would take. 
       Safety Shield  
       [0033]    Furthermore, the volume swept out by robot motion is compact and easily and conveniently enclosed by an external or integrated safety shield. A safety shield is desirable to protect persons working near automated equipment from the hazards of the equipment as well as potential hazards associated with biological specimens. Such a shield also reduces contamination from reaching the specimens from the nearby sources.  FIG. 5  shows an integrated safety shield  110  composed of tiles  111 . The tiled construction is convenient for access to individual instruments, e.g. for maintenance. 
       Robotic Rack for Handling Microtiter Plates  
       [0034]    The robotic strut  11  is uniquely designed to share a structural role with an instrument rack and to provide a means for precisely handling microtiter plates. 
         [0035]      FIG. 6  isolates the robotic strut assembly from the rack mounting positions for clarity and  FIG. 7  shows an exploded view of the strut assembly. Gripper  13  is screwed onto drive nut  63  which can be controllably moved. Similarly, gripper mount  12  is screwed to carriage  40 , of  FIG. 7 , which in turn travels along rail  41  sliding on polymer bearing surfaces. The rail  41  is constructed from extruded aluminum and is fastened to the recessed channel of U-channel  33 . Carriage  40  is mechanically connected to drive belt  95  by belt clamp  94 . Belt  95  is pulled by a drive assembly  30 . The relative position of the drive assembly  30  including stepper motor  31  and motor driver  34  is also visible in  FIG. 7 . The drive assembly  30  is bolted to strut  11  using mount holes  42   a  and  42   b.    
         [0036]    In operation, the robotic strut delivers or removes a microtiter plate from a receiving position in a mounted instrument. A microtiter plate  20  (shown in  FIG. 2 ) is gripped by gripper  13  and translated vertically along strut  11  until it is suitably aligned with a receiving port (not shown) of a mounted instrument. The plate then moves horizontally along gripper mount  12  and is deposited in an instrument receptacle (not shown). 
       Robotic Rack Components  
       [0037]    The robotic strut assembly is composed of several sub-assemblies including a gripper  13 , a gripper mount  12  and a drive assembly  30  shown in greater detail in  FIG. 8  through  FIG. 12 . 
         [0038]    The top view of the preferred gripper assembly  13  is shown in  FIG. 8 . A left  32   a  and right  32  jaw are mounted to movable carriages  56  and  57  respectively. Each carriage moves along a portion of a single linear rail  58  mounted to a base platform  59  and is threaded onto a portion of a lead screw. The left lead screw  54  is mechanically coupled to rotate in unison with the right lead screw  55  but is oppositely threaded. A DC motor  50  is coupled to the left lead screw portion  54  and controlled by control board  51 . The control board includes optical limit switches  53  and  53   a  to signal jaw position and gripper assembly position relative to the gripper mount (not shown in  FIG. 8 ). The control board is connected to a power source and central control assembly  71  (shown in  FIG. 10 ) using a suitable cable inserted into receptacle  52 . 
         [0039]    In operation, a command signal is sent to control board  51  to turn on motor  50 . As the motor rotates, coupled lead screws  54  and  55  rotate causing the gripper jaws  32   a  and  32  to move by driving the carriages  56  and  57  along the rail  58 . The direction of jaw motion either increases or decreases the separation of the jaws and is determined by the direction of the motor rotation and relative threading of the lead screws  54  and  55 . The jaw motion continues until the optical limit switch  53  is triggered. The arrangement is intended to provide two controlled positions for the jaws: open or closed. In the open position, the jaws can release a microtiter plate or be positioned around a plate. In the closed position, the jaws grip a microtiter plate. 
         [0040]    The gripper assembly  13  is in turn mounted to a linearly actuated arrangement on gripper mount  12 .  FIG. 9  shows the gripper mount and linear actuator assembly. A DC motor  60  is mounted by flange  67  to a structural base  66 . A pulley  68  is mounted to the motor and rotates when electrical power is applied to the motor. The motor receives power through cable  65  threaded down through a cable port  64  and connected to control board  51  (not shown in this view). A toothed belt  61  delivers motion from the motor to a pulley  69  attached to lead screw  62  which is also mounted to structural base  66 . A drive nut  63  is threaded onto lead screw  62  and mounted to gripper assembly  13 . 
         [0041]    In operation, electrical current is applied to the motor  60  causing the rotation of pulley  68  which is transferred to pulley  69  by the belt  61 . Rotation of pulley  69  turns lead screw  62  and causes drive nut  63  to move linearly along the screw. Thus, attached gripper  13  moves linearly forward or backward as indicated by the arrow. 
         [0042]    The preferred gripper mount  12  is attached to a movable carriage  40  housed in strut assembly  11  and driven vertically along the rail  41 .  FIG. 10  is a sideview of strut assembly  11  showing its orientation relative to components of the vertical drive arrangement  72  and central control assembly  71 . 
         [0043]      FIG. 11  is an enlarged view of vertical drive components and the central control assembly. The vertical drive is comprised of a stepper motor  31  (not visible) on whose shaft is mounted a drive pulley  90  and an optical encoder disk  85 . A toothed drive belt  95  engages pulley  90  and is guided around several idler pulleys including pulley  92 . Motor driver and encoder electronics are arranged on driver board  84  which receives power and communication via cable  81  additionally connected to the central control assembly  71 . System power and programmatic communication with a personal computer (not shown) are provided by cables  82  and  83  respectively. 
         [0044]    In operation, commands are sent from the central control assembly  71  to driver board  84  and subsequently instruct the stepper motor  31  to rotate. The motor&#39;s rotation causes rotation of mounted drive pulley  90  which effectively pulls belt  95 . The complete belt path for the vertical drive assembly  95   a  is shown in  FIG. 12 . The belt is pulled around idlers  91 ,  92 , and  93  and is attached to carriage  40  by belt clamp  94 . Thus, as the belt is pulled, the carriage is pulled vertically along its rail  41 . Mechanical friction in the assembly including holding torque of the stepper motor  maintains position of the carriage with plate payload. 
       ALTERNATIVE DESIGNS AND ASSEMBLIES 
       [0045]    Additional alternative designs and assemblies are within the scope of this disclosure and although several are described they are not intended to define the scope of the invention or to be otherwise limiting.