Abstract:
A method for replacing a first sample carried on a moving secondary conveyor onto a moving primary conveyor at a potential interference point while the primary conveyor is transporting a second sample

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an automated clinical sample handling worksystem with two or more independent processing stations having samples supplied thereto by an automated conveyor system. More particularly, the present invention relates to a method for enabling samples to return to the conveyor from a processing station without interfering with samples on the conveyor. 
       BACKGROUND OF THE INVENTION 
       [0002]    Clinical diagnostic analyzers are being developed with increasing levels of complexity and sophistication in order to fully automated the performance of chemical assays and immunoassays of biological fluid samples such as urine, blood serum, plasma, cerebrospinal liquids and the like, these fluid samples almost universally being contained in open or capped sample tubes. Generally, chemical reactions between an analyte in a patient&#39;s biological sample and reagents used during performing the assay result in generating various signals that can be measured by the analyzer. From these signals the concentration of the analyte in the sample may be calculated. 
         [0003]    A wide variety of automated chemical analyzers are known in the art and are continually being improved to increase analytical menu and throughput, reduce turnaround time, and decrease requisite sample volumes. See for example, U.S. Pat. Nos. 6,103,193, and 6,027,691 and 5,482,861. Such improvements, while necessary in themselves, may be hampered if sufficient corresponding advances are not made in the automation of pre-analytical sample preparation and handling operations like sorting, batch preparation, centrifugation of sample tubes to separate sample constituents, cap removal to facilitate fluid access, and the like. 
         [0004]    Automated sample pre-treatment systems generally include the use of conveyor systems for conveying specimens to analyzers, such as those described in U.S. Pat. Nos. 5,178,834, and 5,209,903. Typical of such systems, a sample is transported to an analyzer by a primary conveyor and either removed from the primary conveyor by a robotic-like device and placed into a sampling area of an adjacent analyzer or may be shuttled onto an analyzer-specific conveyor that transports the sample to the sampling area of an adjacent analyzer. In the later instance, when sufficient sample aliquots have been removed from the sample, the sample is returned to the primary conveyor and transferred thereto from the analyzer-specific conveyor. 
         [0005]    As automated clinical chemistry sample handling workstations become increasingly complex, the number of instances wherein samples interfere with one another during transportation processes also increase. Clearly, a problem to be avoided is any form of interference between the sample transferring from the analyzer-specific conveyor with samples already on the primary conveyor and being transported thereby. 
         [0006]    U.S. Pat. No. 6,019,945 discloses a transfer mechanism for transferring a sample container holder between a conveyor line and a sampling area formed in each of several analyzers, the transfer mechanism being connectable to each one of the plurality of analyzers. At least two analyzers units are different from one other in either the types of reagent supply means, the number of analysis items that can be analyzed, the number of tests that can be processed in a unit time, or the species of samples to be processed. 
         [0007]    U.S. Pat. No. 5,087,423 discloses a plurality of analyzing modules, a plurality of analyzing routes and at least one bypass route bypassing at least one analyzing module are arranged. Each analyzing module is capable of analyzing samples with respect to one or more items, and samples successively supplied from the introduction sides of the modules are selectively delivered into each module. 
         [0008]    U.S. Pat. No. 6,060,022, automatically presents pre-treated samples in open containers to robotic devices operated in conjunction with independent stand-alone analyzers. In order to provide precise and accurate handling of the sample tubes, it is critical to position and align the tubes within a sample tube carrier accurately so that the various robotic handling devices may automatically and consistently remove or replace tubes from tube carriers as needed. 
         [0009]    Although these prior art systems have advanced sample handling and processing throughput, what has not been addressed is the challenge of replacing a sample onto a moving conveyor belt while the belt is conveying other samples without adversely affecting either of the two samples. 
       SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a method for replacing a sample onto a moving primary conveyor while the conveyor is conveying other samples without adversely affecting either of the two samples. As a first step, any samples transported on the primary conveyor are stopped or slowed down at a position upstream of the sample transferring from an analyzer-specific conveyor onto a primary conveyor. As a second step, samples on the primary conveyor are stopped or slowed down in a manner that eliminates abrupt or uncontrolled motions that might otherwise disturb the sample. This new method for operating a sample handling worksystem provides an improved capability to operate a clinical laboratory&#39;s automated sample handling worksystem by improving the overall reliability and efficiency of moving and processing samples. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    For a better understanding of the invention as well as other objects and further features thereof, reference is made to the following detailed description of various preferred embodiments thereof, taken in connection with the accompanying drawings wherein: 
           [0012]      FIG. 1  is a simplified schematic plan view of an automated sample handling system including a conveyor controlled in cooperation with several chemical analysis pre-treatment devices and analyzers in which the present invention may be employed advantageously; 
           [0013]      FIG. 2  is a simplified elevation view of a sample tube carrier adapted for use in the sample handling system of  FIG. 1 ; 
           [0014]      FIG. 3  is a simplified plan view of a prior art approach to handle samples within the sample handling system of  FIG. 1 ; 
           [0015]      FIG. 4  is an enlarged view of a portion of  FIG. 3  illustrating a first failure mode of the prior art; 
           [0016]      FIG. 5  is an enlarged view of a portion of  FIG. 3  illustrating a second failure mode of the prior art; 
           [0017]    FIGS.  6 - 6 A- 6 B- 6 C is a schematic view of the present invention for handling sample within the automated sample handling system of  FIG. 1 ; 
           [0018]      FIG. 7  is a cut-away perspective view of the sample handling device of  FIG. 6 ; 
           [0019]      FIG. 8  is an enlarged perspective view of the sample handling device of  FIG. 6 ; 
           [0020]      FIG. 9  is an exploded perspective view of the sample handling device of  FIG. 6 ; 
           [0021]      FIG. 10  is top plan view of a key feature of the sample handling device of  FIG. 6 ; and, 
           [0022]      FIG. 11  illustrates the sample handling device of  FIG. 6  installed on the sample handling system of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    Referring to  FIG. 1 , there is illustrated an automated clinical chemistry sample handling worksystem  10  capable of automatically pre-processing as necessary multiple sample containers  20 , typically sample test tubes, contained in multiple sample racks  18  so as to practice the present invention. Typically, patient specimens to be automatically processed are provided to sample handling system  10  in multiple containers, such as test tubes, which can be capped. Each of the sample containers  20  is provided with container identification indicia, such as a bar code, indicating a patient&#39;s identification, as well as, optionally, the assay procedures to be accomplished upon the sample therein. The containers are generally held in one or more holders such as racks that may have additional identification indicia thereon. 
         [0024]    The sample handling worksystem  10  comprises an operating base  12  on which a belt-like conveyor track  14  transports a plurality of individual sample tube containers  20  carried in sample tube carriers  22  from a sample tube loading/unloading station  16  to an automated centrifuge  24  to an automated tube de-capper  30  for automatically removing caps from capped sample containers  20  and to one or more conventional clinical analyzers  32 ,  38 , and  42  before returning each sample container  20  to the sample tube loading/unloading robotic station  16 . It will be understood that more than three analyzers  32 ,  38 , and  42  may be linked by conveyor track  14 , but for purposes of simplicity, only three are shown. The sample handling worksystem  10  has a number of sensors, not illustrated, for detecting the location of a sample tube container  20  by means of identifying indicia placed on or within each sample tube carrier  22 . Conventional bar-code readers may be employed in such tracking operations. 
         [0025]    Centrifuge  24  and each analyzer  38 ,  42  and  32  are generally equipped with various robotic mechanisms  26  and  28 ,  40  and  44  or analyzer tracks  34  and  36 , respectively, for removing a sample tube carrier  22  from conveyor track  14 , moving the sample tube carrier  22  to and from centrifuge  24 , to and from or into and out from analyzers  38 ,  42  and  32 , respectively. Typically, the loading/unloading station  16  includes at least two robotic arms  21  conventionally equipped with clamping robotic hands. 
         [0026]    The sample handling worksystem  10  is controlled by a conventional computer  15  preferably a microprocessor based central processing unit CPU  15  housed as part of or separate from the system  10  to move the sample tube carrier  22  to each operating station  24 ,  30 ,  32 ,  38 ,  42  and  16  whereat various types of assay processing occurs. CPU  15  controls sample handling system  10  according to software, firmware, or hardware commands or circuits like those used on the Dimension® clinical chemistry analyzer sold by Dade Behring Inc. of Deerfield, Ill., and are typical of those skilled in the art of computer-based electromechanical control programming. 
         [0027]      FIG. 2  is an elevation view of an exemplary sample tube carrier  22  for transporting a cylindrical sample tube container  20  shown in phantom lines having a tube diameter and a tube longitudinal height, the carrier comprising a generally cylindrical lower carrier body  50  having a central axis  50 A and a cylindrical hole  52  formed along said axis depending from a top surface  51  of the carrier body  50  towards a bottom surface  49  of the carrier body  50 . An optional recess  53  centered along axis  50 A may be seen, recess  53  provided to accommodate the rounded bottom typically found on clinical sample tube containers  20 . Carrier body  50  has at least two vertically oriented arms  54  symmetrically disposed within the cylindrical hole  52  and extending a distance upwards above the top surface  51 . The vertically oriented arms  54  include a tapered upper end  56  seen tapered downwardly towards the central axis  50 A. 
         [0028]      FIG. 3  illustrates a typical instance addressed by the present invention in which a sample tube carrier  22 A, having been analyzed as requested by clinical analyzer  32 , is being returned along analyzer track  36  to conveyor track  14  (illustrated herein as moving in a counter-clockwise direction) before being additionally tested and/or removed from conveyor track  14  and/or retained in storage within system  10 . Conventional sensors S, typically light beam or proximity type, are positioned strategically along conveyor track  14  in a manner to anticipate a potential interference at interference point  35  between sample tube carrier  22 A entering conveyor track  14  and sample tube carrier  22 C being transported along conveyor track  14 . In prior art systems, illustrated in  FIG. 3 , it is common practice to install a sensor-actuated plunger  23  adjacent conveyor track  14  and adapted to extend above the surface of conveyor track  14  stopping movement of sample tube carrier  22 C prior to reaching interference point  35 . Alternately sensor-actuated plunger  23  may be installed adjacent analyzer track  36  and adapted to extend above the surface of analyzer track  36  stopping movement of sample tube carrier  22 A prior to reaching interference point  35 . As seen in enlarged  FIG. 4 , a problem encountered in such prior art solutions is that the plunger  23  may be “late” and physically contact sample tube carrier  22 C in a glancing manner that causes the sample tube  20  to be tilted and possibly spill liquid patient sample contained therein. Alternately, as seen in  FIG. 5 , plunger  23  may be “even later” and physically contact sample tube carrier  22 C in a pinning manner that causes sample tube carrier  22 C to be pinned against a wall or rail normally positioned alongside conveyor track  14 . 
         [0029]    These and similar problems are eliminated by the present invention in which each and every sample tube carrier  22 C that is transported along conveyor track  14  is led through a generally propeller-shaped turnstile  60  ( FIG. 10 ) as it approaches a potential interference point  35 . The generally propeller-shaped turnstile  60  acts to cradle sample tube carriers  22 C and is adapted with a suitable plunger so that its rotation may be stopped at any time a sample tube carrier  22 A approaches potential interference point  35 . What has been discovered is that if a fast lateral force is applied to the sample, the potential for re-suspension and/or spill (along with the potential for cross contamination of samples) is increased. Prior art stop gates that have motion generally perpendicular to the sample path potentially causes such problems. The present invention avoids such problems by providing a gate that has that a gate orientation designed to slow down the gate speed or to provide some degree of elasticity to the plunger so that there is not enough force to cause spills or re-suspension. This is achieved in the present invention by having the stop cylinder stop or slow down the turnstile thereby stopping or slowing down the sample. By using the turnstile of the present invention, the sample may be slowed down by reducing the drag of the braking force. 
         [0030]      FIG. 6  schematically illustrates generally propeller-shaped rotatably mounted adjacent conveyor track  14  around a mounting pin  61  that is exemplary of the present invention. FIGS.  6 A- 6 B- 6 C schematically illustrate how generally propeller-shaped  60  rotates “clockwise” as sample tube carrier  22 C traverses along conveyor track  14 . 
         [0031]      FIG. 7  is a cut-away perspective illustration showing sample tube carrier  22 C cradled within turnstile  60  in an orientation comparable to the schematic illustration in  FIG. 6B . A turnstile locking mechanism  62  ( FIG. 9 ) is provided in order to arrest rotation of turnstile  60  so that movement of sample tube carrier  22 C may be stopped at any time a sample tube carrier  22 A approaches potential interference point  35 . Alternately, an adjustable drag force may be applied to turnstile  60  so that sample tube carrier  22 C may be slowed down. Drag forces may be applied using the plunger  65  ( FIG. 9 ) adjusted to slow the turnstile  60  ( FIG. 9 ) with pin  66  ( FIG. 9 ) rather than stop it completely.  FIG. 8  is a simplified view of  FIG. 7  illustrating turnstile  60  in position beneath locking mechanism  62 , the locking mechanism  62  comprising a mounting bracket  64  for supporting an actuatable plunger  65  positioned so that pin  66  of plunger  65  may be thrust through opening  67  in bracket  64  and locking rotation of turnstile  60 . 
         [0032]      FIG. 10  is an exemplary illustration of turnstile  60  comprising two pairs of radially extending blades  67  symmetrically disposed about a central axis  60 A. A mounting pin hole  69  sized to accept pin  61  is centered in a circular mounting pad  70  also symmetrically disposed about central axis  60 A. 
         [0033]    In operation, described in conjunction with  FIGS. 9 and 11 , actuatable plunger  65  of turnstile locking mechanism  62  is normally un-activated so that turnstile  60  may freely rotate on pin  61  allowing sample tube carriers  22 C to be transported along conveyor track  14  through interference point  35  without being stopped. Alternately, a braking force may be applied to turnstile  60  so that it slowly rotates on pin  61  causing sample tube carriers  22 C to be slowed down as they are transported along conveyor track  14  through interference point  35 . In the event sensor S 1  detects another sample tube carrier  22 A released from analyzer  32  and approaching interference point  35 , plunger  65  of turnstile locking mechanism  62  is activated so that pin  66  is thrust through opening  67 , thereby and locking rotation of turnstile  60  and preventing sample tube carriers  22 C from being transported along conveyor track  14  through interference point  35 . Plunger  65  may be activated by conventional means such as by air pressure or electromagnetic solenoid. After sample tube carrier  22 A has passed through interference point  35 , plunger  65  is un-activated so that turnstile  60  may again freely rotate and sample tube carriers  22 C may be freely transported along conveyor track  14 . 
         [0034]    Those skilled in the art will appreciate that the embodiments of the invention disclosed herein are illustrative of the principles of the invention and that other modifications may be employed which are still within the scope of the invention. For example, obvious variants of the invention would include turnstile  60  comprising three radially extending blades  67  as might be preferable in the instance of larger diameter sample tube carriers  20 . Another obvious variant of the invention would include any propeller-shaped turnstile comprising multiple blades rotatably mounted proximate the primary conveyor.